The following is a selective (not exhaustive) collection of abstracts related to invasion of GBM and other gliomas.  The abstracts are presented in reverse chronological order (most recent first).  Note that there is also an extensive literature on tumor invasion for other types of tumors, or tumors in general, additional to the literature on invasion of GBM or gliomas in particular.

Also see Tumor Angiogenesis & Anti-Angiogenic Treatment for related information.

____________________

Expert Rev Neurother. 2009 Apr;9(4):519-34.

Therapeutic strategies for inhibiting invasion in glioblastoma.

Drappatz J, Norden AD, Wen PY.

Center for Neuro-Oncology, Dana Farber Cancer Institute, 44 Binney Street, Boston
MA 02115, USA. jdrappatz@partners.org

Glioblastomas are the most common and lethal form of malignant primary brain
tumors. Although some progress has been made, the impact of recent advances in
multimodality therapies on clinical outcome has been disappointing, with a median
survival of less than 15 months. A major challenge in patients with glioblastomas
is the propensity of the tumor to invade into adjacent brain tissue. Invasive
tumor cells escape surgical removal and, because of their reduced proliferation
rate and increased resistance to apoptosis, they are relatively resistant to
radiation therapy and chemotherapy. Recently, there has been important progress
in understanding the molecular determinants of glioma invasion and migration.
This review will summarize some of the therapeutic strategies for inhibiting
invasion in glioblastomas.

PMID: 19344303 [PubMed - in process]

____________________

Cancer Res. 2009 Apr 14. [Epub ahead of print]

Multiparameter Computational Modeling of Tumor Invasion.

Bearer EL, Lowengrub JS, Frieboes HB, Chuang YL, Jin F, Wise SM, Ferrari M, Agus
DB, Cristini V.

Department of Pathology and Laboratory Medicine, and Division of Engineering,
Brown University, Providence, Rhode Island; Department of Biology, California
Institute of Technology, Pasadena, California; Departments of Mathematics and
Biomedical Engineering, University of California, Irvine, California; School of
Health Information Sciences, Division of Nanomedicine, and Department of
Biomedical Engineering, University of Texas Health Science Center; Departments of
Experimental Therapeutics and Systems Biology, The University of Texas M. D.
Anderson Cancer Center; Department of Bioengineering, Rice University, Houston,
Texas; Department of Biomedical Engineering, The University of Texas, Austin,
Texas; Department of Mathematics, University of Tennessee, Knoxville, Tennessee;
and USC Center for Applied Molecular Medicine, University of Southern California,
Los Angeles, California.

Clinical outcome prognostication in oncology is a guiding principle in
therapeutic choice. A wealth of qualitative empirical evidence links disease
progression with tumor morphology, histopathology, invasion, and associated
molecular phenomena. However, the quantitative contribution of each of the known
parameters in this progression remains elusive. Mathematical modeling can provide
the capability to quantify the connection between variables governing growth,
prognosis, and treatment outcome. By quantifying the link between the tumor
boundary morphology and the invasive phenotype, this work provides a quantitative
tool for the study of tumor progression and diagnostic/prognostic applications.
This establishes a framework for monitoring system perturbation towards
development of therapeutic strategies and correlation to clinical outcome for
prognosis. [Cancer Res 2009;69(10):OF1-9].

PMID: 19366801 [PubMed - as supplied by publisher]

____________________

Expert Opin Ther Targets. 2009 Apr;13(4):455-68.

Anti-VEGF therapies for malignant glioma: treatment effects and escape
mechanisms.

Miletic H, Niclou SP, Johansson M, Bjerkvig R.

Department of Biomedicine, University of Bergen, NorLux Neuro-Oncology, Bergen,
Norway. Hrvoje.Miletic@biomed.uib.no

BACKGROUND: Glioblastoma multiforme (GBM) has a very poor prognosis and novel
treatment strategies are urgently needed. GBM appears to be an optimal target for
anti-angiogenic therapy as the tumour shows a high degree of endothelial cell
proliferation and pro-angiogenic growth factor expression. OBJECTIVE: To examine
the role of angiogenic factors (particularly VEGF) in glioma and whether
inhibition of these factors can be used as a treatment. METHODS: A review of
relevant literature. RESULTS/CONCLUSIONS: Anti-angiogenic therapy has fulfilled
the proof of concept in glioma animal models. In glioma patients, the efficacy of
anti-angiogenic mono-therapies initially has been disappointing. However recent
clinical trials combining bevacizumab, an anti-VEGF antibody, with chemotherapy
reported very encouraging response rates. Although randomized phase III clinical
trials with anti-angiogenic molecules are not yet available for GBM patients,
this treatment regimen is already applied off protocol in several clinical
centers. It should be kept in mind though that tumours can develop escape
mechanisms. In particular invasive cells, which migrate away from the highly
vascularized tumour core, are not targeted by anti-angiogenic therapies. In our
opinion, the future of anti-angiogenic therapy will rely on a combination
strategy including chemotherapy and drugs that target invasive glioma cells.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 19335067 [PubMed - in process]

____________________

Int J Oncol. 2009 Apr;34(4):1051-60.

SNS-032 prevents hypoxia-mediated glioblastoma cell invasion by inhibiting
hypoxia inducible factor-1alpha expression.

Ali MA, Reis A, Ding LH, Story MD, Habib AA, Chattopadhyay A, Saha D.

Department of Radiation Oncology, Division of Molecular Radiation Biology,
University of Texas Southwestern Medical Center, Dallas, TX 75390-9187, USA.

Hypoxia and hypoxia inducible factor-1alpha (HIF-1alpha) play a critical role in
glioblastoma (GBM) which is characterized by highly aggressive and widespread
cell invasion into adjacent normal brain tissue. The purpose of this study was to
investigate the effect of the novel aminothiazole com-pound SNS-032 in
glioblastoma cell invasion under hypoxic condition. SNS-032 is a potent and
selective inhibitor of cyclin-dependent kinases 2, 7 and 9 and inhibits both cell
cycle and transcription. We analyzed the effect of SNS-032 (0.5 microM) on
HIF-1alpha expression and its major trans-regulating factors including COX-2,
VEGF, MMP-2 and uPAR that are involved in cellular invasion in tumor hypoxia. Our
observations demonstrate SNS-032: i) inhibited hypoxia-induced U87MG cell
invasion and among all the other inhibitors tested, SNS-032 is the most
effective, ii) blocked HIF-1alpha mediated transcription of COX-2, MMP-2, VEGF
and uPAR expression in U87MG cells in response to hypoxia, iii) blocked
HIF-1alpha expression by a proteasome independent pathway. The effects were
similar to those observed with HIF-1alpha siRNA which prevented cellular invasion
by blocking HIF-1alpha expression and its downstream effectors. Taken together,
our data suggest that SNS-032 prevents hypoxia-mediated U87MG cell invasion by
blocking the expression of HIF-1alpha and its trans-regulating factors. Our
results present an opportunity in controlling highly invasive tumors such as
glioblastoma using this novel class of compounds.

PMID: 19287962 [PubMed - in process]

____________________

Neoplasia. 2009 Apr;11(4):377-87.

NHERF-1: modulator of glioblastoma cell migration and invasion.

Kislin KL, McDonough WS, Eschbacher JM, Armstrong BA, Berens ME.

Cancer and Cell Biology Division, Translational Genomics Research Institute,
Phoenix, AZ 85004, USA.

The invasive nature of malignant gliomas is a clinical problem rendering tumors
incurable by conventional treatment modalities such as surgery, ionizing
radiation, and temozolomide. Na(+)/H(+) exchanger regulatory factor 1 (NHERF-1)
is a multifunctional adaptor protein, recruiting cytoplasmic signaling proteins
and membrane receptors/transporters into functional complexes. This study
revealed that NHERF-1 expression is increased in highly invasive cells that
reside in the rim of glioblastoma multiforme (GBM) tumors and that NHERF-1
sustains glioma migration and invasion. Gene expression profiles were evaluated
from laser capture-microdissected human GBM cells isolated from patient tumor
cores and corresponding invaded white matter regions. The role of NHERF-1 in the
migration and dispersion of GBM cell lines was examined by reducing its
expression with small-interfering RNA followed by radial migration,
three-dimensional collagen dispersion, immunofluorescence, and survival assays.
The in situ expression of NHERF-1 protein was restricted to glioma cells and the
vascular endothelium, with minimal to no detection in adjacent normal brain
tissue. Depletion of NHERF-1 arrested migration and dispersion of glioma cell
lines and caused an increase in cell-cell cohesiveness. Glioblastoma multiforme
cells with depleted NHERF-1 evidenced a marked decrease in stress fibers, a
larger cell size, and a more rounded shape with fewer cellular processes. When
NHERF-1 expression was reduced, glioma cells became sensitized to temozolomide
treatment resulting in increased apoptosis. Taken together, these results provide
the first evidence for NHERF-1 as a participant in the highly invasive phenotype
of malignant gliomas and implicate NHERF-1 as a possible therapeutic target for
treatment of GBM.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

PMID: 19308292 [PubMed - in process]

____________________

J Cancer Res Clin Oncol. 2009 Mar 10. [Epub ahead of print]

Recurrence pattern in glioblastoma multiforme patients treated with anti-angiogenic chemotherapy.

Tuettenberg J, Grobholz R, Seiz M, Brockmann MA, Lohr F, Wenz F, Vajkoczy P.

Department of Neurosurgery, Universitätsmedizin Mannheim, University of
Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167, Mannheim, Germany,
jochen.tuettenberg@nch.ma.uni-heidelberg.de.

PURPOSE: Glioblastoma multiforme is the prototype of an angiogenic tumour. Under
experimental conditions, anti-angiogenic therapy strategies lead to an increased
invasion. Here we report on the pattern of tumour recurrence in glioblastoma
patients treated with an anti-angiogenic chemotherapy. PATIENTS AND METHODS: A
total of 32 patients with glioblastoma multiforme and a residual tumour mass
after operation were treated with a continuous low-dose chemotherapy with
temozolomide and a COX-II inhibitor, a presumably anti-angiogenic therapy.
RESULTS: While anti-tumour activity of this therapy regimen was excellent with a
mean overall time to progression of 10.4 (+/-0.9) months and a mean overall
survival of 17.8 (+/-1.5) months, an unusually high rate of distant recurrences
was observed (62.5%). CONCLUSION: Patients treated with an anti-angiogenic
chemotherapy experience distant recurrences at a higher rate than reported for
conventional therapies. This may reflect an anti-angiogenic therapy-induced
activation of glioma invasion confirming similar recently published experimental
results.

PMID: 19277712 [PubMed - as supplied by publisher]

____________________

Cancer Cell. 2009 Mar 3;15(3):220-31.

Comment in:
    Cancer Cell. 2009 Mar 3;15(3):167-70.

Antiangiogenic therapy elicits malignant progression of tumors to increased local
invasion and distant metastasis.

Pàez-Ribes M, Allen E, Hudock J, Takeda T, Okuyama H, Viñals F, Inoue M, Bergers
G, Hanahan D, Casanovas O.

Translational Research Laboratory, Catalan Institute of Oncology, IDIBELL, 08907
L'Hospitalet de Llobregat, Spain.

Multiple angiogenesis inhibitors have been therapeutically validated in
preclinical cancer models, and several in clinical trials. Here we report that
angiogenesis inhibitors targeting the VEGF pathway demonstrate antitumor effects
in mouse models of pancreatic neuroendocrine carcinoma and glioblastoma but
concomitantly elicit tumor adaptation and progression to stages of greater
malignancy, with heightened invasiveness and in some cases increased lymphatic
and distant metastasis. Increased invasiveness is also seen by genetic ablation
of the Vegf-A gene in both models, substantiating the results of the
pharmacological inhibitors. The realization that potent angiogenesis inhibition
can alter the natural history of tumors by increasing invasion and metastasis
warrants clinical investigation, as the prospect has important implications for
the development of enduring antiangiogenic therapies.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

PMID: 19249680 [PubMed - indexed for MEDLINE]

____________________

Glia. 2009 Feb 3. [Epub ahead of print]

Imaging glioma cell invasion in vivo reveals mechanisms of dissemination and
peritumoral angiogenesis.

Winkler F, Kienast Y, Fuhrmann M, Von Baumgarten L, Burgold S, Mitteregger G,
Kretzschmar H, Herms J.

Department of Neurology, Ludwig-Maximilians University, Munich, Germany.

Infiltration of cancer cells into normal tissue is a hallmark of malignant
gliomas and compromises treatment options. A lack of appropriate models limits
the study of this invasion in vivo, which makes it difficult to fully understand
its anatomy and the role of dynamic interactions with structures of the normal
brain. We developed a novel methodology by utilizing multiphoton laser scanning
microscopy (MPLSM) to image the movement of glioma cells deep within the normal
brain of live mice in real time. This allowed us to track the invasion of
individual RFP-expressing GL261 cells in relation to perfused vasculature or
GFP-labeled endothelial cells repetitively over days, up to a depth of 0.5 mm.
Glioma cells moved faster and more efficiently when the abluminal site of a blood
vessel was utilized for invasion. Cells that invaded perivascularly were
frequently found next to (a) multiple capillary structures where microvessels run
parallel to each other, (b) capillary loops or glomeruloid-like bodies, and (c)
dilated capillaries. Dynamic MPLSM for more than 48 h revealed that single
invasive glioma cells induced intussusceptive microvascular growth and capillary
loop formation, specifically at the microvascular site with which they had
contact. As the main tumor grew by cooption of existing brain vessels, these
peritumoral vascular changes may create a beneficial environment for glioma
growth. In conclusion, our study revealed new mechanisms of peritumoral
angiogenesis and invasion in gliomas, providing an explanation for their
interdependence. (c) 2009 Wiley-Liss, Inc.

PMID: 19191326 [PubMed - as supplied by publisher]

____________________

J Neurosurg. 2009 Jan;110(1):173-80.

Antiangiogenic therapy using bevacizumab in recurrent high-grade glioma: impact on local control and patient survival.

Narayana A, Kelly P, Golfinos J, Parker E, Johnson G, Knopp E, Zagzag D, Fischer
I, Raza S, Medabalmi P, Eagan P, Gruber ML.

Department of Radiation Oncology, New York University Medical Center, New York,
New York, USA. ashwatha.narayana@nyumc.org

OBJECT: Antiangiogenic agents have recently shown impressive radiological
responses in high-grade glioma. However, it is not clear if the responses are
related to vascular changes or due to antitumoral effects. The authors report the
mature results of a clinical study of bevacizumab-based treatment of recurrent
high-grade gliomas. METHODS: Sixty-one patients with recurrent high-grade gliomas
received treatment with bevacizumab at 10 mg/ kg every 2 weeks for 4 doses in an
8-week cycle along with either irinotecan or carboplatin. The choice of
concomitant chemotherapeutic agent was based on the number of recurrences and
prior chemotherapy. RESULTS: At a median follow-up of 7.5 months (range 1-19
months), 50 (82%) of 61 patients relapsed and 42 patients (70%) died of the
disease. The median number of administered bevacizumab cycles was 2 (range 1-7
cycles). The median progression-free survival (PFS) and overall survival (OS)
were 5 (95% confidence interval [CI] 2.3-7.7) and 9 (95% CI 7.6-10.4) months,
respectively, as calculated from the initiation of the bevacizumab-based therapy.
Radiologically demonstrated responses following therapy were noted in 73.6% of
cases. Neither the choice of chemotherapeutic agent nor the performance of a
resection prior to therapy had an impact on patient survival. Although the
predominant pattern of relapse was local, 15 patients (30%) had diffuse disease.
CONCLUSIONS: Antiangiogenic therapy using bevacizumab appears to improve survival
in patients with recurrent high-grade glioma. A possible change in the
invasiveness of the tumor following therapy is worrisome and must be closely
monitored.

PMID: 18834263 [PubMed - indexed for MEDLINE]

____________________

Cell Prolif. 2008 Dec;41(6):980-7.

Evolutionary game theory elucidates the role of glycolysis in glioma progression
and invasion.

Basanta D, Simon M, Hatzikirou H, Deutsch A.

Zentrum für Informationsdienste und Hochleistungsrechnen, Technische Universität
Dresden, Dresden, Germany. david.basanta@moffitt.org

OBJECTIVES: Tumour progression has been described as a sequence of traits or
phenotypes that cells have to acquire if the neoplasm is to become an invasive
and malignant cancer. Although genetic mutations that lead to these phenotypes
are random, the process by which some of these mutations become successful and
cells spread is influenced by tumour microenvironment and the presence of other
cell phenotypes. It is thus likely that some phenotypes that are essential in
tumour progression will emerge in the tumour population only with prior presence
of other different phenotypes. MATERIALS AND METHODS: In this study, we use
evolutionary game theory to analyse the interactions between three different
tumour cell phenotypes defined by autonomous growth, anaerobic glycolysis, and
cancer cell invasion. The model allows us to understand certain specific aspects
of glioma progression such as the emergence of diffuse tumour cell invasion in
low-grade tumours. RESULTS: We have found that the invasive phenotype is more
likely to evolve after appearance of the glycolytic phenotype which would explain
the ubiquitous presence of invasive growth in malignant tumours. CONCLUSIONS: The
result suggests that therapies, which increase the fitness cost of switching to
anaerobic glycolysis, might decrease probability of the emergence of more
invasive phenotypes.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 19040573 [PubMed - indexed for MEDLINE]

____________________

Proc Inst Mech Eng [H]. 2008 Oct;222(7):1149-60.

Engineering of clinical glioma treatment: prediction of pro-invasive molecular
events in treated gliomas.

Trog D, Yeghiazaryan K, Schild HH, Golubnitschaja O.

Department of Radiology, University of Bonn, Bonn, Germany.

The diffusely infiltrative nature of malignant gliomas is the main obstacle to
successful treatment approaches. Advanced simulation models of the in vivo
response to therapy conditions are expected to improve malignant glioma treatment
substantially. In parallel experiments, human malignant glioma cells underwent
either radiation or chemotherapy treatment (chemotreatment) with temozolomide
alone, or combined chemoradiation. Cells were treated according to diverse,
clinically relevant, therapeutic algorithms. Quantitative 'real-time' polymerase
chain reaction (PCR) measurements were performed for target genes, namely
vascular endothelial growth factor, p53, and cyclooxygenase-2, which allow a
comparative evaluation of pro-invasive molecular events in treated gliomas. The
proof-of-principle study simulated variable intratumoural regional conditions.
Pro-invasive molecular patterns were strongly dependent on the treatment
algorithm, cellular density, and drug delivery. The highest pro-invasive
potential was demonstrated for simulated peripheral regions under continued
chemoradiation. This result strongly supports the clinical observations of
increased aggressiveness and relatively poor response to second-line therapies in
post-operatively chemoradiation-treated malignant gliomas at the time of relapse.
Individualized and potentially the most effective treatment algorithms can be
designed using established gene expression patterns applied on primary cell
cultures obtained from individual patients. Individual drug toxicity and response
to anti-cancer therapy can be predicted.

PMID: 19024162 [PubMed - indexed for MEDLINE]

____________________

Neuro Oncol. 2008 Oct;10(5):690-9. Epub 2008 Aug 20.

Lithium inhibits invasion of glioma cells; possible involvement of glycogen
synthase kinase-3.

Nowicki MO, Dmitrieva N, Stein AM, Cutter JL, Godlewski J, Saeki Y, Nita M,
Berens ME, Sander LM, Newton HB, Chiocca EA, Lawler S.

Dardinger Laboratory for Neuro-oncology and Neurosciences, Department of
Neurological Surgery, The Ohio State University Medical Center, Columbus, OH
43210, USA.

Therapies targeting glioma cells that diffusely infiltrate normal brain are
highly sought after. Our aim was to identify novel approaches to this problem
using glioma spheroid migration assays. Lithium, a currently approved drug for
the treatment of bipolar illnesses, has not been previously examined in the
context of glioma migration. We found that lithium treatment potently blocked
glioma cell migration in spheroid, wound-healing, and brain slice assays. The
effects observed were dose dependent and reversible, and worked using every
glioma cell line tested. In addition, there was little effect on cell viability
at lithium concentrations that inhibit migration, showing that this is a specific
effect. Lithium treatment was associated with a marked change in cell morphology,
with cells retracting the long extensions at their leading edge. Examination of
known targets of lithium showed that inositol monophosphatase inhibition had no
effect on glioma migration, whereas inhibition of glycogen synthase kinase-3
(GSK-3) did. This suggested that the effects of lithium on glioma cell migration
could possibly be mediated through GSK-3. Specific pharmacologic GSK-3 inhibitors
and siRNA knockdown of GSK-3alpha or GSK-3beta isoforms both reduced cell
motility. These data outline previously unidentified pathways and inhibitors that
may be useful for the development of novel anti-invasive therapeutics for the
treatment of brain tumors.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

PMID: 18715951 [PubMed - indexed for MEDLINE]

____________________

Cancer Res. 2008 Jul 1;68(13):5267-72.

Nitrosoureas inhibit the stathmin-mediated migration and invasion of malignant
glioma cells.

Liang XJ, Choi Y, Sackett DL, Park JK.

Surgical and Molecular Neuro-oncology Unit, National Institute of Neurological
Disorders, National Institute of Child Health and Human Development, NIH,
Bethesda, Maryland, USA.

Malignant gliomas are the most common primary intrinsic brain tumors and are
highly lethal. The widespread migration and invasion of neoplastic cells from the
initial site of tumor formation into the surrounding brain render these lesions
refractory to definitive surgical treatment. Stathmin, a
microtubule-destabilizing protein that mediates cell cycle progression, can also
regulate directed cell movement. Nitrosoureas, traditionally viewed as DNA
alkylating agents, can also covalently modify proteins such as stathmin. We
therefore sought to establish a role for stathmin in malignant glioma cell
motility, migration, and invasion and determine the effects of nitrosoureas on
these cell movement-related processes. Scratch wound-healing recovery, Boyden
chamber migration, Matrigel invasion, and organotypic slice invasion assays were
performed before and after the down-regulation of cellular stathmin levels and in
the absence and presence of sublethal nitrosourea
([1-(2-chloroethyl)-3-cyclohexyl-l-nitrosourea]; CCNU) concentrations. We show
that decreases in stathmin expression lead to significant decreases in malignant
glioma cell motility, migration, and invasion. CCNU, at a concentration of 10
micromol/L, causes similar significant decreases, even in the absence of any
effects on cell viability. The direct inhibition of stathmin by CCNU is likely a
contributing factor. These findings suggest that the inhibition of stathmin
expression and function may be useful in limiting the spread of malignant gliomas
within the brain, and that nitrosoureas may have therapeutic benefits in addition
to their antiproliferative effects.

Publication Types:
    Research Support, N.I.H., Intramural

PMID: 18593927 [PubMed - indexed for MEDLINE]

____________________

Cancer. 2008 Aug 15;113(4):841-6.

Invasive tumor cells and prognosis in a selected population of patients with
glioblastoma multiforme.

Mangiola A, de Bonis P, Maira G, Balducci M, Sica G, Lama G, Lauriola L, Anile C.

Department of Neurological Sciences, Institute of Neurosurgery, Catholic
University School of Medicine, Rome, Italy.

BACKGROUND: After surgical resection, the residual, invasive glioblastoma (GBM)
cells give rise to a recurrent tumor, which, in 96% of patients, arises adjacent
to the resection margin. METHODS: In this study, the authors prospectively
enrolled 25 patients with GBM who underwent gross total resection followed by
adjuvant radiochemotherapy (with temozolomide). Tumor removal was achieved with
resection margins that included the neighboring, apparently normal tissue
(between 1 cm and 2 cm from the tumor border [B area]) and the tumor. RESULTS:
Patients who had an absence of tumor cells in the neighboring, apparently normal
white matter (B area) had better survival than patients who had the presence of
tumor cells in the B area (21 months vs 12 months). This difference was
statistically significant in univariate analysis (P = .005) and in multivariate
analysis (P = .01). CONCLUSIONS: Aggressive tumor removal may improve survival,
but the current results indicated that biologic commitment of 'penumbra' cells
appear to be the most relevant factor for tumor recurrence and accounts for the
fatal outcome of the disease. 2008 American Cancer Society

Publication Types:
    Clinical Trial

PMID: 18618580 [PubMed - indexed for MEDLINE]

____________________

J Clin Neurosci. 2008 Jul;15(7):725-37. Epub 2008 May 12.

Invadopodia: at the cutting edge of tumour invasion.

Stylli SS, Kaye AH, Lock P.

Department of Surgery, University of Melbourne, Cell Signaling Laboratory, Level
5, Clinical Sciences Building, Royal Melbourne Hospital, Parkville, Victoria
3050, Australia.

Invasion of tissues by malignant tumours is facilitated by tumour cell migration
and degradation of extracellular matrix (ECM) barriers. Several invasive
neoplasms, including head and neck squamous cell carcinoma, breast carcinoma,
melanoma and glioma, contain tumour cells that can form actin-rich protrusions
with ECM proteolytic activity called invadopodia. These dynamic organelle-like
structures adhere to, and digest, collagens, laminins and fibronectin.
Invadopodia are dependent on multiple transmembrane, cytoplasmic and secreted
proteins engaged in cell adhesion, signal transduction, actin assembly, membrane
regulation and ECM proteolysis. Strategies aimed at disrupting invadopodia could
form the basis of novel anti-invasive therapies for treating patients. Here we
review the molecular basis of invadopodia formation with particular emphasis on
the intracellular signaling networks that are essential for invadopodia activity
and examine the potential role of these structures in glioma invasion.

Publication Types:
    Research Support, Non-U.S. Gov't
    Review

PMID: 18468901 [PubMed - indexed for MEDLINE]

____________________

Cancer Res. 2008 Mar 15;68(6):1945-52.

Cannabinoids inhibit glioma cell invasion by down-regulating matrix
metalloproteinase-2 expression.

Blázquez C, Salazar M, Carracedo A, Lorente M, Egia A, González-Feria L, Haro A,
Velasco G, Guzmán M.

Department of Biochemistry and Molecular Biology I, School of Biology,
Complutense University, Madrid, Spain.

Cannabinoids, the active components of Cannabis sativa L. and their derivatives,
inhibit tumor growth in laboratory animals by inducing apoptosis of tumor cells
and impairing tumor angiogenesis. It has also been reported that these compounds
inhibit tumor cell spreading, but the molecular targets of this cannabinoid
action remain elusive. Here, we evaluated the effect of cannabinoids on matrix
metalloproteinase (MMP) expression and its effect on tumor cell invasion. Local
administration of Delta(9)-tetrahydrocannabinol (THC), the major active
ingredient of cannabis, down-regulated MMP-2 expression in gliomas generated in
mice, as determined by Western blot, immunofluorescence, and real-time
quantitative PCR analyses. This cannabinoid-induced inhibition of MMP-2
expression in gliomas (a) was MMP-2-selective, as levels of other MMP family
members were unaffected; (b) was mimicked by JWH-133, a CB(2) cannabinoid
receptor-selective agonist that is devoid of psychoactive side effects; (c) was
abrogated by fumonisin B1, a selective inhibitor of ceramide biosynthesis; and
(d) was also evident in two patients with recurrent glioblastoma multiforme. THC
inhibited MMP-2 expression and cell invasion in cultured glioma cells.
Manipulation of MMP-2 expression by RNA interference and cDNA overexpression
experiments proved that down-regulation of this MMP plays a critical role in
THC-mediated inhibition of cell invasion. Cannabinoid-induced inhibition of MMP-2
expression and cell invasion was prevented by blocking ceramide biosynthesis and
by knocking-down the expression of the stress protein p8. As MMP-2 up-regulation
is associated with high progression and poor prognosis of gliomas and many other
tumors, MMP-2 down-regulation constitutes a new hallmark of cannabinoid
antitumoral activity.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 18339876 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 2008 Feb;86(3):297-309. Epub 2007 Oct 11.

Autotaxin: a secreted autocrine/paracrine factor that promotes glioma invasion.

Hoelzinger DB, Nakada M, Demuth T, Rosensteel T, Reavie LB, Berens ME.

Cancer and Cell Biology Division, Translational Genomics Research Institute, 445
North 5th Street, 5th floor, Phoenix, AZ 85004, USA.

Glioblastoma multiforme (GBM) is inherently invasive, and it is from the invasive
cell population that the tumor recurs. The GBM invasion transcriptome reveals
over-expression of various autocrine factors that could act as motility drivers,
such as autotaxin (ATX). Some of these factors could also have paracrine roles,
modulating the behavior of cells in the peri-tumoral brain parenchyma. ATX
generates lysophosphatidic acid (LPA), which signals through LPA receptors
expressed by GBM as well as in astrocytes, oligodendrocytes (ODC) and microglia;
their activation manifest cell specific effects. ATX stimulates invasion of GBM
cells in vitro and ex vivo invasion assays. ATX activity enhances GBM adhesion in
cells expressing the LPA1 receptor, as well as stimulating rac activation. GBM
secreted ATX can also have paracrine effects: ATX activity results in reduced ODC
adhesion. ODC monolayer invasion showed that U87 and U251 GBM cells expressing
ATX invaded through an ODC monolayer significantly more than cells depleted of
ATX or cells expressing inactive ATX, suggesting that GBM cells secreting ATX
find ODCs less of a barrier than cells that do not express ATX. Secreted factors
that drive GBM invasion can have autocrine and paracrine roles; one stimulates
GBM motility and the other results in ODC dis-adhesion.

Publication Types:
    In Vitro

PMID: 17928955 [PubMed - indexed for MEDLINE]

____________________

Neurosci Res. 2008 Jan;60(1):40-9. Epub 2007 Sep 29.

Expression of matrix metalloproteinases MMP-1, MMP-11 and MMP-19 is correlated
with the WHO-grading of human malignant gliomas.

Stojic J, Hagemann C, Haas S, Herbold C, Kühnel S, Gerngras S, Roggendorf W,
Roosen K, Vince GH.

University of Würzburg, Department of Neurosurgery, Tumorbiology Laboratory,
Josef-Schneider-Strasse 11, D-97080 Würzburg, Germany.

Glioblastomas (GBM) are the most prevalent type of malignant primary brain tumor
in adults. They may manifest de novo or develop from low-grade astrocytomas (LGA)
or anaplastic astrocytomas. They are characterized by an aggressive local growth
pattern and a marked degree of invasiveness, resulting in poor prognosis. Tumor
progression is facilitated by an increased activity of proteolytic enzymes such
as matrix metalloproteinases (MMPs). Elevated levels of several MMPs were found
in glioblastomas compared to LGA and normal brain (NB). However, data for some
MMPs, like MMP-1, are controversially discussed and other MMPs like MMP-11 and
MMP-19 have as yet not been analysed in detail. We examined the expression of
MMP-1, MMP-9, MMP-11 and MMP-19 in NB, LGA and GBM by semiquantitative RT-PCR,
Western blotting and immunohistochemistry and found an enhanced expression of
these MMPs in GBM compared to LGA or NB in signal strength and in the percentage
of tumors displaying MMP expression. The transition from LGA to GBM was
characterized by a shift of pro-MMP-11 to expression of the active enzyme.
Therefore, MMP-1, MMP-11 and MMP-19 might be of importance for the development of
high-grade astrocytic tumors and may be promising targets for therapy.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 17980449 [PubMed - indexed for MEDLINE]

____________________

Acta Neuropathol. 2007 Nov;114(5):443-58. Epub 2007 Sep 6.

Diffuse glioma growth: a guerilla war.

Claes A, Idema AJ, Wesseling P.

Department of Pathology, Radboud University Nijmegen Medical Centre, PO Box 9101,
6500 HB, Nijmegen, The Netherlands. a.claes@pathol.umcn.nl

In contrast to almost all other brain tumors, diffuse gliomas infiltrate
extensively in the neuropil. This growth pattern is a major factor in therapeutic
failure. Diffuse infiltrative glioma cells show some similarities with guerilla
warriors. Histopathologically, the tumor cells tend to invade individually or in
small groups in between the dense network of neuronal and glial cell processes.
Meanwhile, in large areas of diffuse gliomas the tumor cells abuse pre-existent
"supply lines" for oxygen and nutrients rather than constructing their own.
Radiological visualization of the invasive front of diffuse gliomas is difficult.
Although the knowledge about migration of (tumor)cells is rapidly increasing, the
exact molecular mechanisms underlying infiltration of glioma cells in the
neuropil have not yet been elucidated. As the efficacy of conventional methods to
fight diffuse infiltrative glioma cells is limited, a more targeted ("search &
destroy") tactic may be needed for these tumors. Hopefully, the study of original
human glioma tissue and of genotypically and phenotypically relevant glioma
models will soon provide information about the Achilles heel of diffuse
infiltrative glioma cells that can be used for more effective therapeutic
strategies.

Publication Types:
    Research Support, Non-U.S. Gov't
    Review

PMID: 17805551 [PubMed - indexed for MEDLINE]

____________________

J Natl Cancer Inst. 2007 Nov 7;99(21):1583-93. Epub 2007 Oct 30.

Autocrine factors that sustain glioma invasion and paracrine biology in the brain
microenvironment.

Hoelzinger DB, Demuth T, Berens ME.

Cancer and Cell Biology Division, Translational Genomics Research Institute, 445
North Fifth Street, Phoenix, AZ 85004, USA.

Invasion is a defining hallmark of glioblastoma multiforme, just as metastasis
characterizes other high-grade tumors. Glial tumors invariably recur due to the
regrowth of invasive cells, which are unaffected by standard treatment
modalities. Drivers of glioma invasion include autocrine signals propagated by
secreted factors that signal through receptors on the tumor. These secreted
factors are able to diffuse through the peritumoral stroma, thereby influencing
parenchymal cells that surround the tumor mass. Here we describe various
autocrine motility factors that are expressed by invasive glioma cells and
explore the effects that they may have on normal cells present in the path of
invasion. Conversely, normal brain parenchymal cells secrete ligands that can
stimulate receptors on invasive glioma cells and potentially facilitate glioma
invasion or create a permissive microenvironment for malignant progression.
Parallel observations have been made for solid tumors of epithelial origin, in
which parenchymal and stromal cells either support or suppress tumor invasion.
Most autocrine and paracrine interactions involved in glioma invasion constitute
known signaling systems in stages of central nervous system development that
involve the migration of precursor cells that populate the developing brain. Key
paracrine interactions between glioma cells and the brain microenvironment can
influence glioma pathobiology and therefore contribute to its poor prognosis.
Current therapies for glioma that could have an impact on paracrine communication
between tumors and normal cells are discussed. We suggest that cells in the
normal brain parenchyma be considered as potential targets for adjuvant therapies
to control glioma growth because such cells are less likely to develop resistance
than glioma cells.

Publication Types:
    Research Support, N.I.H., Extramural
    Review

PMID: 17971532 [PubMed - indexed for MEDLINE]

____________________

Neuro Oncol. 2007 Oct;9(4):424-9. Epub 2007 Jul 10.

Relationship of glioblastoma multiforme to neural stem cell regions predicts
invasive and multifocal tumor phenotype.

Lim DA, Cha S, Mayo MC, Chen MH, Keles E, VandenBerg S, Berger MS.

Department of Neurological Surgery, University of California, San Francisco, CA
94143, USA. limd@neurosurg.ucsf.edu

Neural stem cells with astrocyte-like characteristics exist in the human brain
subventricular zone (SVZ), and these cells may give rise to glioblastoma
multiforme (GBM). We therefore analyzed MRI features of GBMs in specific relation
to the SVZ. We reviewed the preoperative and serial postoperative MR images of 53
patients with newly diagnosed GBM. The spatial relationship of the
contrast-enhancing lesion (CEL) with the SVZ and cortex was determined
preoperatively. Classification was as follows: group I, CEL contacting SVZ and
infiltrating cortex; group II, CEL contacting SVZ but not involving cortex; group
III, CEL not contacting SVZ but involving cortex; and group IV, CEL neither
contacting SVZ nor infiltrating cortex. Patients with group I GBMs (n = 16) were
most likely to have multifocal disease at diagnosis (9 patients, 56%, p = 0.001).
In contrast, group IV GBMs (n = 14) were never multifocal. Group II (n = 14) and
group III (n = 9) GBMs were multifocal in 11% and 29% of cases, respectively.
Group I GBMs always had tumor recurrences noncontiguous with the initial
lesion(s), while group IV GBM recurrences were always bordering the primary
lesion. Group I GBMs may be most related to SVZ stem cells; these tumors were in
intimate contact with the SVZ, were most likely to be multifocal at diagnosis,
and recurred at great distances to the initial lesion(s). In contrast, group IV
GBMs were always solitary lesions; these may arise from non-SVZ, white matter
glial progenitors. Our MRI-based classification of GBMs may further our
understanding of GBM histogenesis and help predict tumor recurrence pattern.

PMID: 17622647 [PubMed - indexed for MEDLINE]

____________________

Cancer Res. 2007 Oct 1;67(19):9463-71.

Erratum in:
    Cancer Res. 2007 Nov 1;67(21):10624.

Autocrine glutamate signaling promotes glioma cell invasion.

Lyons SA, Chung WJ, Weaver AK, Ogunrinu T, Sontheimer H.

Department of Neurobiology, Center for Glial Biology in Medicine, University of
Alabama at Birmingham, Birmingham, Alabama 35294, USA.

Malignant gliomas have been shown to release glutamate, which kills surrounding
brain cells, creating room for tumor expansion. This glutamate release occurs
primarily via system xC, a Na+-independent cystine-glutamate exchanger. We show
here, in addition, that the released glutamate acts as an essential
autocrine/paracrine signal that promotes cell invasion. Specifically, chemotactic
invasion and scrape motility assays each show dose-dependent inhibition of cell
migration when glutamate release was inhibited using either S-(4)-CPG or
sulfasalazine, both potent blockers of system xC. This inhibition could be
overcome by the addition of exogenous glutamate (100 micromol/L) in the continued
presence of the inhibitors. Migration/invasion was also inhibited when
Ca2+-permeable alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors
(AMPA-R) were blocked using GYKI or Joro spider toxin, whereas CNQX was
ineffective. Ca2+ imaging experiments show that the released glutamate activates
Ca2+-permeable AMPA-R and induces intracellular Ca2+ oscillations that are
essential for cell migration. Importantly, glioma cells release glutamate in
sufficient quantities to activate AMPA-Rs on themselves or neighboring cells,
thus acting in an autocrine and/or paracrine fashion. System xC and the
appropriate AMPA-R subunits are expressed in all glioma cell lines,
patient-derived glioma cells, and acute patient biopsies investigated.
Furthermore, animal studies in which human gliomas were xenographed into scid
mice show that chronic inhibition of system xC-mediated glutamate release leads
to smaller and less invasive tumors compared with saline-treated controls. These
data suggest that glioma invasion is effectively disrupted by inhibiting an
autocrine glutamate signaling loop with a clinically approved candidate drug,
sulfasalazine, already in hand.

Publication Types:
    Research Support, N.I.H., Extramural

PMID: 17909056 [PubMed - indexed for MEDLINE]

____________________

Neuroimage. 2007;37 Suppl 1:S59-70. Epub 2007 Mar 23.

Computer simulation of glioma growth and morphology.

Frieboes HB, Lowengrub JS, Wise S, Zheng X, Macklin P, Bearer EL, Cristini V.

School of Health Information Sciences, University of Texas Health Science Center
at Houston, USA.

Despite major advances in the study of glioma, the quantitative links between
intra-tumor molecular/cellular properties, clinically observable properties such
as morphology, and critical tumor behaviors such as growth and invasiveness
remain unclear, hampering more effective coupling of tumor physical
characteristics with implications for prognosis and therapy. Although molecular
biology, histopathology, and radiological imaging are employed in this endeavor,
studies are severely challenged by the multitude of different physical scales
involved in tumor growth, i.e., from molecular nanoscale to cell microscale and
finally to tissue centimeter scale. Consequently, it is often difficult to
determine the underlying dynamics across dimensions. New techniques are needed to
tackle these issues. Here, we address this multi-scalar problem by employing a
novel predictive three-dimensional mathematical and computational model based on
first-principle equations (conservation laws of physics) that describe
mathematically the diffusion of cell substrates and other processes determining
tumor mass growth and invasion. The model uses conserved variables to represent
known determinants of glioma behavior, e.g., cell density and oxygen
concentration, as well as biological functional relationships and parameters
linking phenomena at different scales whose specific forms and values are
hypothesized and calculated based on in vitro and in vivo experiments and from
histopathology of tissue specimens from human gliomas. This model enables
correlation of glioma morphology to tumor growth by quantifying interdependence
of tumor mass on the microenvironment (e.g., hypoxia, tissue disruption) and on
the cellular phenotypes (e.g., mitosis and apoptosis rates, cell adhesion
strength). Once functional relationships between variables and associated
parameter values have been informed, e.g., from histopathology or intra-operative
analysis, this model can be used for disease diagnosis/prognosis, hypothesis
testing, and to guide surgery and therapy. In particular, this tool identifies
and quantifies the effects of vascularization and other cell-scale glioma
morphological characteristics as predictors of tumor-scale growth and invasion.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, U.S. Gov't, Non-P.H.S.

PMID: 17475515 [PubMed - indexed for MEDLINE]

____________________

Cell Mol Life Sci. 2007 Feb;64(4):458-78.

Molecular targets of glioma invasion.

Nakada M, Nakada S, Demuth T, Tran NL, Hoelzinger DB, Berens ME.

Cancer and Cell Biology Division, The Translational Genomics Research Institute,
445 North Fifth Street, Phoenix, Arizona, 85004, USA.

Glioblastoma multiforme is the most common and lethal primary malignant brain
tumor. Although considerable progress has been made in technical proficiencies of
surgical and radiation treatment for brain tumor patients, the impact of these
advances on clinical outcome has been disappointing, with median survival time
not exceeding 15 months. Over the last 30 years, no significant increase in
survival of patients suffering from this disease has been achieved. A fundamental
source of the management challenge presented in glioma patients is the insidious
propensity of tumor invasion into distant brain tissue. Invasive tumor cells
escape surgical removal and geographically dodge lethal radiation exposure and
chemotherapy. Recent improved understanding of biochemical and molecular
determinants of glioma cell invasion provide valuable insight into the underlying
biological features of the disease, as well as illuminating possible new
therapeutic targets. These findings are moving forward to translational research
and clinical trials as novel antiglioma therapies.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't
    Review

PMID: 17260089 [PubMed - indexed for MEDLINE]

____________________

J Neuropathol Exp Neurol. 2007 Jan;66(1):1-9.

The evolution of mathematical modeling of glioma proliferation and invasion.

Harpold HL, Alvord EC Jr, Swanson KR.

Department of Pathology, University of Washington, Seattle, Washington, USA.

Gliomas are well known for their potential for aggressive proliferation as well
as their diffuse invasion of the normal-appearing parenchyma peripheral to the
bulk lesion. This review presents a history of the use of mathematical modeling
in the study of the proliferative-invasive growth of gliomas, illustrating the
progress made in understanding the in vivo dynamics of invasion and proliferation
of tumor cells. Mathematical modeling is based on a sequence of observation,
speculation, development of hypotheses to be tested, and comparisons between
theory and reality. These mathematical investigations, iteratively compared with
experimental and clinical work, demonstrate the essential relationship between
experimental and theoretical approaches. Together, these efforts have extended
our knowledge and insight into in vivo brain tumor growth dynamics that should
enhance current diagnoses and treatments.

Publication Types:
    Research Support, Non-U.S. Gov't
    Review

PMID: 17204931 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 2006 Sep;79(2):135-42. Epub 2006 Apr 6.

Inhibition of matrix degrading enzymes and invasion in human glioblastoma (U87MG)
cells by isoflavones.

Puli S, Lai JC, Bhushan A.

Department of Pharmaceutical Sciences, College of Pharmacy and Biomedical
Research Institute, Idaho State University, Pocatello, ID 83209, USA.

Glioblastoma multiforme is a primary brain tumor associated with extensive
invasion into surrounding brain tissue. Matrix metalloproteinases (MMPs) and
urokinase plasminogen activation (uPA) system are shown to be involved in tumor
invasion as they help in degradation of extracellular matrix (ECM) proteins and
thus assist in the movement of cells. MMP-2 and 9 were shown to be upregulated in
gliomas, suggesting their involvement in invasion. Genistein and biochanin A are
isoflavones commonly known as phytoestrogens and have some anticancer properties.
We hypothesize that these two isoflavones can induce a lowering of tumor invasion
by decreasing the activity of matrix degrading enzymes. In this study we
investigated the effects of genistein and biochanin A on invasive activity of
U87MG cells using the Calbiochem in vitro invasion assay system. Our results
suggest that genistein and biochanin A induced a decrease in invasive activity of
U87MG cells in a dose-related manner. Genistein also induced a decrease in
EGF-stimulated invasion thereby implicating an involvement of EGF-mediated
signaling in invasion. Our results also show that treatment of U87MG cells with
the two isoflavones induced decreases in the enzymatic activity of MMP-9 and the
protein levels of MT1-MMP and uPAR.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

PMID: 16598420 [PubMed - indexed for MEDLINE]

____________________

Eur J Pharmacol. 2006 Aug 7;542(1-3):8-15. Epub 2006 May 24.

Pro-invasive gene regulating effect of irradiation and combined
temozolomide-radiation treatment on surviving human malignant glioma cells.

Trog D, Yeghiazaryan K, Fountoulakis M, Friedlein A, Moenkemann H, Haertel N,
Schueller H, Breipohl W, Schild H, Leppert D, Golubnitschaja O.

Department of Radiology, Friedrich-Wilhelms-University of Bonn, D-53105 Germany.

The current chemotherapeutic treatment of glioblastoma patients has minor
success. Little is known about the molecular and cellular mechanisms of the
resistance of gliomas towards current therapies. This study investigated both
suppressive cellular effects and regulation of extracellular matrix remodeling
proteins with pro-invasive activity in surviving human glioblastoma cells under
clinically relevant treatments. All cellular and molecular biological
investigations were performed on the genetically well-defined and clinically
relevant p53-wild type U87Mg glioma cells. Malignant glioma cells underwent
either radiation or temozolomide treatments alone, or combined chemo/radio
treatment. Protein expression patterns were investigated by two-dimensional
polyacrylamide gel electrophoresis followed by protein spot identification using
tandem mass spectrometry analysis. Specific expression levels were quantified by
Western-blotting. Extracellular gelatinase activities for both metalloproteinases
MMP-2 and MMP-9 were determined by zymogramms. Survival curves indicated no
effective suppression of glioma cells under all treatment conditions tested.
Morphological changes demonstrated sub-lethal effect of both temozolomide and
combined treatment. Expression of MMP-2, MMP-9, and membrane type 1 matrix
metalloproteinases (MT1-MMP) was differentially up-regulated by increasing
cellular density and treatment conditions. A significantly enhanced extracellular
degrading activity under all treatment conditions tested was demonstrated for
MMP-2 only. Being a marker for brain tumour progression and angiogenesis,
lysozyme c was highly up-regulated under the combined chemo/radio treatment. The
activation of proteins with pro-invasive activity indicates an increasing
malignancy grade of surviving glioma cells under treatment conditions tested
correlating well with more aggressive tumour phenotypes observed clinically in
recurrences of treated glioblastomas.

PMID: 16806166 [PubMed - indexed for MEDLINE]

____________________

Expert Rev Mol Diagn. 2006 Jul;6(4):613-26.

Molecular pathways triggering glioma cell invasion.

Salhia B, Tran NL, Symons M, Winkles JA, Rutka JT, Berens ME.

The Arthur & Sonia Labatt Brain Tumour Research Center, The Hospital for Sick
Children, The University of Toronto, Toronto, Ontario, Canada.
bodour.salhia@utoronto.ca

The efficacy of treating malignant gliomas with adjuvant therapies remains
largely unsuccessful due to the inability to effectively target invading cells.
Although our understanding of glioma oncogenesis has steadily improved, the
molecular mechanisms that mediate glioma invasion are still poorly understood. It
is clear that genetic alterations in malignant gliomas affect cell proliferation
and cell cycle control, which are the targets of most chemotherapeutic agents.
However, effective therapy against cell invasion has been less successful. Future
treatment protocols must incorporate pharmacotherapeutic strategies that target
resistant infiltrative glioma cells as well as proliferating ones. Thus,
delineating the point of convergence of signaling pathways, which mediate glioma
invasion, proliferation and apoptosis, may identify novel targets that can serve
as possible points of therapeutic intervention. The optimization of novel
strategies will require reliable preclinical testing using an in vivo animal
model of brain invasion. Current applications of existing animal models are not
currently optimized or characterized for use in glioma invasion research. As
such, the development of a bona fide brain invasion model in vivo must be
established. Progress in understanding molecular mechanisms driving glioma
invasion will be critical to the success of managing and improving the outcome of
patients with this grave disease.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't
    Review

PMID: 16824034 [PubMed - indexed for MEDLINE]

____________________

Glia. 2006 Jun;53(8):799-808.

Transplanted glioma cells migrate and proliferate on host brain vasculature: a
dynamic analysis.

Farin A, Suzuki SO, Weiker M, Goldman JE, Bruce JN, Canoll P.

Department Neurological Surgery, Columbia University, College of Physicians and
Surgeons, New York, NY 10032, USA.

Glioma cells have a remarkable capacity to infiltrate the brain and migrate long
distances from the tumor, making complete surgical resection impossible. Yet,
little is known about how glioma cells interact with the complex microenvironment
of the brain. To investigate the patterns and dynamics of glioma cell
infiltration and migration, we stereotactically injected eGFP and DsRed-2 labeled
rat C6 glioma cells into neonatal rat forebrains and used time-lapse microscopy
to observe glioma cell migration and proliferation in slice cultures generated
from these brains. In this model, glioma cells extensively infiltrated the brain
by migrating along the abluminal surface of blood vessels. Glioma cells
intercalated their processes between the endothelial cells and the perivascular
astrocyte end feet, but did not invade into the blood vessel lumen. Dynamic
analysis revealed notable similarities between the migratory behavior of glioma
cells and that previously observed for glial progenitor cells. Glioma cells had a
characteristic leading process and migrated in a saltatory fashion, with bursts
of migration separated by periods of immobility, and maximum speeds of over 100
microm/h. Migrating glioma cells proliferated en route, pausing for as short as
an hour to divide before the daughter cells resumed migrating. Remarkably, the
majority of glioma cell divisions took place at or near vascular branch points,
suggesting that mitosis is triggered by local environmental cues. This study
provides the first dynamic analysis of glioma cell infiltration in living brain
tissue and reveals that the migration and proliferation of transplanted glioma
cells is directed by interactions with host brain vasculature.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

PMID: 16541395 [PubMed - indexed for MEDLINE]

____________________

Phys Rev Lett. 2006 May 12;96(18):188103. Epub 2006 May 11.

Dynamics and pattern formation in invasive tumor growth.

Khain E, Sander LM.

Department of Physics and Michigan Center for Theoretical Physics, The University
of Michigan, Ann Arbor, Michigan 48109, USA.

We study the in vitro dynamics of the malignant brain tumor glioblastoma
multiforme. The growing tumor consists of a dense proliferating zone and an outer
less dense invasive region. Experiments with different types of cells show
qualitatively different behavior: one cell line invades in a spherically
symmetric manner, but another gives rise to branches. We formulate a model for
this sort of growth using two coupled reaction-diffusion equations for the cell
and nutrient concentrations. When the ratio of the nutrient and cell diffusion
coefficients exceeds some critical value, the plane propagating front becomes
unstable with respect to transversal perturbations. The instability threshold and
the full phase-plane diagram in the parameter space are determined. The results
are in a qualitative agreement with experimental findings for the two types of
cells.

Publication Types:
    Research Support, N.I.H., Extramural

PMID: 16712401 [PubMed - indexed for MEDLINE]

____________________

Cancer Res. 2006 Feb 1;66(3):1597-604.

An integrated computational/experimental model of tumor invasion.

Frieboes HB, Zheng X, Sun CH, Tromberg B, Gatenby R, Cristini V.

Department of Biomedical Engineering, University of California-Irvine, Irvine, CA
92697-2715, USA.

The intracellular and extracellular dynamics that govern tumor growth and
invasiveness in vivo remain poorly understood. Cell genotype and phenotype, and
nutrient, oxygen, and growth factor concentrations are key variables. In previous
work, using a reaction-diffusion mathematical model based on variables that
directly describe tumor cell cycle and biology, we formulated the hypothesis that
tumor morphology is determined by the competition between heterogeneous cell
proliferation caused by spatial diffusion gradients, e.g., of cell nutrients,
driving shape instability and invasive tumor morphologies, and stabilizing
mechanical forces, e.g., cell-to-cell and cell-to-matrix adhesion. To test this
hypothesis, we here obtain variable-based statistics for input to the
mathematical model from in vitro human and rat glioblastoma cultures. A linear
stability analysis of the model predicts that glioma spheroid morphology is
marginally stable. In agreement with this prediction, for a range of variable
values, unbounded growth of the tumor mass and invasion of the environment are
observed in vitro. The mechanism of invasion is recursive subspheroid component
development at the tumor viable rim and separation from the parent spheroid.
Results of computer simulations of the mathematical model closely resemble the
morphologies and spatial arrangement of tumor cells from the in vitro model. We
propose that tumor morphogenesis in vivo may be a function of marginally stable
environmental conditions caused by spatial variations in cell nutrients, oxygen,
and growth factors, and that controlling these conditions by decreasing spatial
gradients could benefit treatment outcomes, whereas current treatment, and
especially antiangiogenic therapy, may trigger spatial heterogeneity (e.g., local
hypoxia), thus causing invasive instability.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, U.S. Gov't, Non-P.H.S.

PMID: 16452218 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 2006 Feb;76(3):227-37.

Radiation enhances the invasive potential of primary glioblastoma cells via
activation of the Rho signaling pathway.

Zhai GG, Malhotra R, Delaney M, Latham D, Nestler U, Zhang M, Mukherjee N, Song
Q, Robe P, Chakravarti A.

Department of Radiation Oncology, Massachusetts General Hospital/Harvard Medical
School, Boston, MA, 02114, USA.

Glioblastoma multiforme (GBM) is among the most treatment-refractory of all human
tumors. Radiation is effective at prolonging survival of GBM patients; however,
the vast majority of GBM patients demonstrate progression at or near the site of
original treatment. We have identified primary GBM cell lines that demonstrate
increased invasive potential upon radiation exposure. As this represents a novel
mechanism by which radiation-treated GBMs can fail therapy, we further
investigated the identity of downstream signaling molecules that enhance the
invasive phenotype of irradiated GBMs. Matrigel matrices were used to compare the
extent of invasion of irradiated vs. non-irradiated GBM cell lines UN3 and GM2.
The in vitro invasive potential of these irradiated cells were characterized in
the presence of both pharmacologic and dominant negative inhibitors of
extracellular matrix and cell signaling molecules including MMP, uPA, IGFR, EGFR,
PI-3K, AKT, and Rho kinase. The effect of radiation on the expression of these
signaling molecules was determined with Western blot assays. Ultimately, the in
vitro tumor invasion results were confirmed using an in vivo 9L GBM model in
rats. Using the primary GBM cell lines UN3 and GM2, we found that radiation
enhances the invasive potential of these cells via activation of EGFR and IGFR1.
Our findings suggest that activation of Rho signaling via PI-3K is required for
radiation-induced invasion, although not required for invasion under physiologic
conditions. This report clearly demonstrates that radiation-mediated invasion is
fundamentally distinct from invasion under normal cellular physiology and
identifies potential therapeutic targets to overcome this phenomenon.

Publication Types:
    Research Support, N.I.H., Extramural
    Research Support, Non-U.S. Gov't

PMID: 16200346 [PubMed - indexed for MEDLINE]

___________________

Clin Cancer Res. 2005 Oct 1;11(19 Pt 1):6772-9.

Morphologic instability and cancer invasion.

Cristini V, Frieboes HB, Gatenby R, Caserta S, Ferrari M, Sinek J.

Department of Biomedical Engineering, University of California, Irvine,
California 92697-2715, USA. cristini@math.uci.edu

PURPOSE: A solid tumor embedded in host tissue is a three-dimensional arrangement
of cells and extracellular matrix that acts as a sink of oxygen and cell
nutrients, thus establishing diffusional gradients. This and variations in
vascular density and blood flow typically produce intratumoral regions of hypoxia
and acidosis, and may result in spatially heterogeneous cell proliferation and
migration. Here, we formulate the hypothesis that through these mechanisms,
microenvironmental substrate gradients may drive morphologic instability with
separation of cell clusters from the tumor edge and infiltration into surrounding
normal tissue. EXPERIMENTAL DESIGN: We used computer simulations and in vitro
experiments. RESULTS: We provide evidence that morphologic instability could be
suppressed in vivo by spatially homogeneous oxygen and nutrient supply because
normoxic conditions act both by decreasing gradients and increasing cell adhesion
and, therefore, the mechanical forces that maintain a well-defined tumor
boundary. A properly working tumor microvasculature can help maintain compact
noninfiltrating tumor morphologies by minimizing oxygen and nutrient gradients.
In contrast, antiangiogenic therapy, by increasing microenvironmental
heterogeneity, may promote morphologic instability, leading to invasive patterns
even under conditions in which the overall tumor mass shrinks. CONCLUSIONS: We
conclude that therapeutic strategies focused solely on reduction of vascular
density may paradoxically increase invasive behavior. This theoretical model
accounts for the highly variable outcome of antiangiogenic therapy in multiple
clinical trials. We propose that antiangiogenic strategies will be more
consistently successful when aimed at "normalizing" the vasculature and when
combined with therapies that increase cell adhesion so that morphologic
instability is suppressed and compact, noninvasive tumor morphologies are
enforced.

PMID: 16203763 [PubMed - indexed for MEDLINE]

____________________
 

Math Med Biol. 2005 Sep;22(3):247-64. Epub 2005 Jul 25.

A mathematical model of dynamic glioma-host interactions: receptor-mediated
invasion and local proteolysis.

MacArthur BD, Please CP, Pettet GJ.

Bone and Joint Research Group, University of Southampton, Southampton General
Hospital, Southampton SO16 6YD, UK. b.d.macarthur@soton.ac.uk

We present a mathematical model of glioma spread based on cellular movement by
receptor-mediated haptotaxis, local proteolysis of healthy tissue components by
glioma-derived proteinases, malignant proliferative enhancement and host
up-regulation of specific key extracellular matrix (ECM) components in response
to the invading glioma. We subsequently consider the nature of glioma-host
interactions as predicted by our model in order to test the hypothesis given in
(Knott et al. (1998) that production of adhesive ECM components by the brain in
response to the invading glioma may have the counter-intuitive effect of
enhancing glioma invasion by assisting haptotactic migration. We suggest that
host production of certain adhesive ECM chemicals can have a profound effect on
both glioma invasion speed and the character of the glioma-host interface. In
particular, we conclude that up-regulation of host ECM production in the vicinity
of the glioma may produce a less diffuse glioma, providing clearer demarcation
between glioma and healthy tissue, and thus improving the possibility of surgical
resection within reasonable bounds.

PMID: 16043631 [PubMed - indexed for MEDLINE]

____________________

Proc Natl Acad Sci U S A. 2005 Jul 26;102(30):10528-33. Epub 2005 Jul 15.

Proliferation and invasion: plasticity in tumor cells.

Gao CF, Xie Q, Su YL, Koeman J, Khoo SK, Gustafson M, Knudsen BS, Hay R,
Shinomiya N, Vande Woude GF.

Laboratory of Molecular Oncology, Van Andel Research Institute, 333 Bostwick
Avenue Northeast, Grand Rapids, MI 49503, USA.

Invasive and proliferative phenotypes are fundamental components of malignant
disease, yet basic questions persist about whether tumor cells can express both
phenotypes simultaneously and, if so, what are their properties. Suitable in
vitro models that allow characterization of cells that are purely invasive are
limited because proliferation is required for cell maintenance. Here, we describe
glioblastoma cells that are highly invasive in response to hepatocyte growth
factor/scatter factor (HGF/SF). From this cell population, we selected subclones
that were highly proliferative or displayed both invasive and proliferative
phenotypes. The biological activities of invasion, migration, urokinase-type
plasminogen activation, and branching morphogenesis exclusively partitioned with
the highly invasive cells, whereas the highly proliferative subcloned cells
uniquely displayed anchorage independent growth in soft agar and were highly
tumorigenic as xenografts in immune-compromised mice. In response to HGF/SF, the
highly invasive cells signal through the MAPK pathway, whereas the selection of
the highly proliferative cells coselected for signaling through Myc. Moreover, in
subcloned cells displaying both invasive and proliferative phenotypes, both
signaling pathways are activated by HGF/SF. These results show how the
mitogen-activated protein kinase and Myc pathways can cooperate to confer both
invasive and proliferative phenotypes on tumor cells and provide a system for
studying how transitions between invasion and proliferation can contribute to
malignant progression.

Publication Types:
    Comparative Study
    Research Support, Non-U.S. Gov't

PMID: 16024725 [PubMed - indexed for MEDLINE]

____________________

Clin Cancer Res. 2005 Jul 1;11(13):4934-40.

Inhibition of glioblastoma angiogenesis and invasion by combined treatments
directed against vascular endothelial growth factor receptor-2, epidermal growth
factor receptor, and vascular endothelial-cadherin.

Lamszus K, Brockmann MA, Eckerich C, Bohlen P, May C, Mangold U, Fillbrandt R,
Westphal M.

Department of Neurosurgery, Institute for Anatomy II, University Hospital
Hamburg-Eppendorf, Hamburg, Germany. lamszus@uke.uni-hamburg.de

PURPOSE: Inhibition of angiogenesis can influence tumor cell invasion and
metastasis. We previously showed that blockade of vascular endothelial growth
factor receptor-2 (VEGFR-2) with the monoclonal antibody DC101 inhibited
intracerebral glioblastoma growth but caused increased tumor cell invasion along
the preexistent vasculature. In the present study, we attempted to inhibit glioma
cell invasion using a monoclonal antibody against the epidermal growth factor
receptor (EGFR), which in the context of human glioblastomas, has been implicated
in tumor cell invasion. In addition, we analyzed whether blockade of vascular
endothelial (VE)-cadherin as a different antiangiogenic target could also inhibit
glioblastoma angiogenesis and growth. EXPERIMENTAL DESIGNS: Nude mice who
received intracerebral glioblastoma xenografts were treated using monoclonal
antibodies against VEGFR-2 (DC101), EGFR (C225), and VE-cadherin (E4G10) either
alone or in different combinations. RESULTS: Increased tumor cell invasion
provoked by DC101 monotherapy was inhibited by 50% to 66% by combined treatment
with C225 and DC101. C225 inhibited glioblastoma cell migration in vitro, but had
no effect on the volume of the main tumor mass or on tumor cell proliferation or
apoptosis in vivo, either alone or in combination with DC101. The
anti-VE-cadherin monoclonal antibody E4G10 was a weaker inhibitor of tumor
angiogenesis and growth than DC101, and also caused a weaker increase in tumor
cell invasion. CONCLUSIONS: Inhibition of angiogenesis achieved by blocking
either VEGFR-2 or VE-cadherin can cause increased glioma cell invasion in an
orthotopic model. Increased tumor cell invasion induced by potent inhibition of
angiogenesis with DC101 could be inhibited by simultaneous blockade of EGFR.

Publication Types:
    Comparative Study
    Research Support, Non-U.S. Gov't

PMID: 16000592 [PubMed - indexed for MEDLINE]

____________________

Lab Invest. 2005 Mar;85(3):328-41.

Downregulation of major histocompatibility complex antigens in invading glioma
cells: stealth invasion of the brain.

Zagzag D, Salnikow K, Chiriboga L, Yee H, Lan L, Ali MA, Garcia R, Demaria S,
Newcomb EW.

Microvascular and Molecular Neuro-oncology Laboratory, New York University School
of Medicine, New York, NY, USA. dz4@nyu.edu

Invasion into surrounding brain tissue is a fundamental feature of gliomas and
the major reason for treatment failure. The process of brain invasion in gliomas
is not well understood. Differences in gene expression and/or gene products
between invading and noninvading glioma cells may identify potential targets for
new therapies. To look for genes associated with glioma invasion, we first
employed Affymetrix microarray Genechip technology to identify genes
differentially expressed in migrating glioma cells in vitro and in invading
glioma cells in vivo using laser capture microdissection. We observed
upregulation of a variety of genes, previously reported to be linked to glioma
cell migration and invasion. Remarkably, major histocompatiblity complex (MHC)
class I and II genes were significantly downregulated in migrating cells in vitro
and in invading cells in vivo. Decreased MHC expression was confirmed in
migrating glioma cells in vitro using RT-PCR and in invading glioma cells in vivo
by immunohistochemical staining of human and murine glioblastomas for beta2
microglobulin, a marker of MHC class I protein expression. To the best of our
knowledge, this report is the first to describe the downregulation of MHC class I
and II antigens in migrating and invading glioma cells, in vitro and in vivo,
respectively. These results suggest that the very process of tumor invasion is
associated with decreased expression of MHC antigens allowing glioma cells to
invade the surrounding brain in a 'stealth'-like manner.

Publication Types:
    Research Support, U.S. Gov't, P.H.S.

PMID: 15716863 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 2005 Mar;72(1):1-9.

Inhibition of cell invasion by indomethacin on glioma cell lines: in vitro study.

Wang M, Yoshida D, Liu S, Teramoto A.

Department of Neurosurgery, The First Hospital, Xi'an Jiaotong University, No.1
Jiankang Road, Xi'an, China. maodewang@yahoo.com.cn

Malignant glioma invasion into the surrounding brain tissue is still a major
problem for any therapeutical methods. Matrix metalloproteinases (MMPs) have been
implicated as important factors in this pathological process. In this study, one
of the non-steroidal anti-inflammatory drugs (NSAIDs) indomethacin was employed
to investigate the effect of inhibition of cell invasion mediated by MMP-2 and
MMP-9 in human malignant glioma cell lines, A172, U87MG, U251MG, and U373MG in
vitro. MTT assay was firstly examined to determine non-cytotoxic dose range, then
gelatin zymography, matrigel invasion assay, migration assay and MMP-2 activity
assay for 24 h exposure in indomethacin were employed to assess the inhibitory
effect of indomethacin. MTT assay revealed that dose with 0, 50, and 500
microM/ml were non-cytotoxic. Zymography demonstrated: (a) expression of MMP-2
and MMP-9 activity was downregulated along with elevated dose of indomethacin.
(b) MMP-2 activity that changed from pro-MMP-2 to active form of MMP-2 in
supernatants of cell lines could not be inhibited by indomethacin. Invasion assay
disclosed that the number of invading cells through the matrigel were
significantly decreased in a dose dependent manner. Migration assay indicated
indomethacin did not affect cells migration. MMP-2 activity assay showed the
total and active MMP-2 secretion was suppressed by 500 microM/ml of indomethacin.
Our present study is the first report on inhibitive effect of indomethacin
mediated by MMP-2 and MMP-9 in invasion assay of glioma cell lines. The current
study suggested that non-cytotoxic level of indomethacin was able to reduce the
cell invasion of malignant gliomas mediated by MMP-2 and MMP-9, but it did not
affected on cell motility. It also lowered down the activity of MMP-2 and MMP-9,
and could reduce of MMP-2 secretion of cell lines. Thus, high concentration of
indomethacin within non-cytotoxic dose might offer a new therapeutic strategy to
impair cell invasion of gliomas.

Publication Types:
    Comparative Study

PMID: 15803368 [PubMed - indexed for MEDLINE]

____________________

Neoplasia. 2005 Jan;7(1):7-16.

Gene expression profile of glioblastoma multiforme invasive phenotype points to
new therapeutic targets.

Hoelzinger DB, Mariani L, Weis J, Woyke T, Berens TJ, McDonough WS, Sloan A,
Coons SW, Berens ME.

Translational Genomics Research Institute (TGen), Phoenix, AZ 85004, USA.

The invasive phenotype of glioblastoma multiforme (GBM) is a hallmark of
malignant process, yet molecular mechanisms that dictate this locally invasive
behavior remain poorly understood. Gene expression profiles of human glioma cells
were assessed from laser capture-microdissected GBM cells collected from paired
patient tumor cores and white matter-invading cell populations. Changes in gene
expression in invading GBM cells were validated by quantitative reverse
transcription polymerase chain reaction (QRT-PCR) and immunohistochemistry in an
independent sample set. QRT-PCR confirmed the differential expression in 19 of 21
genes tested. Immunohistochemical analyses of autotaxin (ATX), ephrin B3, B-cell
lymphoma-w (BCLW), and protein tyrosine kinase 2 beta showed them to be expressed
in invasive glioma cells. The known GBM markers, insulin-like growth factor
binding protein 2 and vimentin, were robustly expressed in the tumor core. A
glioma invasion tissue microarray confirmed the expression of ATX and BCLW in
invasive cells of tumors of various grades. GBM phenotypic and genotypic
heterogeneity is well documented. In this study, we show an additional layer of
complexity: transcriptional differences between cells of tumor core and invasive
cells located in the brain parenchyma. Gene products supporting invasion may be
novel targets for manipulation of brain tumor behavior with consequences on
treatment outcome.

Publication Types:
    Research Support, U.S. Gov't, P.H.S.

PMID: 15720813 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 2004 Nov;70(2):217-28.

Molecular mechanisms of glioma cell migration and invasion.

Demuth T, Berens ME.

TGen, The Translational Genomics Research Institute, Phoenix, Arizona 85004, USA.

Gliomas are the most common intracranial tumors. In the US, approximately 15,000
patients die with glioblastoma per year (CBTRUS 2002). Despite modern diagnostics
and treatments the median survival time does not exceed 15 months. However, it
has long been observed that after surgical removal, tumors recur predominantly
within 1 cm of the resection cavity. This is mainly due to the fact that at the
time of surgery, cells from the bulk tumor have already invaded normal brain
tissue. Decades ago Matsukado showed that more than 50% of untreated brain tumors
had already reached the contralateral hemisphere (J Neurosurg 18: 636-644, 1961).
Therefore one of the most important hallmarks of malignant gliomas is their
invasive behavior. Dandy already recognized the highly invasive characteristics
of this tumor type and performed hemispherectomy in patients with preoperative
hemiplegia (J Am Med Assoc 90: 823-825, 1928). Despite his and others' heroic
efforts, recurrence was detected as early as 3 months after surgery (Bell, LJ: J
Neurosurg 6: 285-293, 1949), leading to the discontinuation of this radical
approach. Diffuse gliomas remain a particularly challenging clinical management
problem. Over the last 20 years no significant increase in survival of patients
suffering from this disease has been achieved. Even drugs directed against newly
identified targets like MMPs or angiogenesis-related targets fail to increase
survival duration (Tonn, Goldbrunner: Acta Neurochir Suppl 88: 163-167, 2003)
Furthermore, anti-angiogenic drugs have been shown to increase glioma
invasiveness, finally leading to gliomatosis cerebri. (Lamszus et al.: Acta
Neurochir Suppl 88: 169-177, 2003). In this review we focus on the main features
which may underlie the invasive phenotype of human gliomas, and offer a
biological basis for optimism towards therapeutic advances to come.

Publication Types:
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, P.H.S.
    Review

PMID: 15674479 [PubMed - indexed for MEDLINE]

____________________

Clin Cancer Res. 2004 Jul 1;10(13):4527-37.

Combinatorial administration of molecules that simultaneously inhibit
angiogenesis and invasion leads to increased therapeutic efficacy in mouse models
of malignant glioma.

Bello L, Lucini V, Costa F, Pluderi M, Giussani C, Acerbi F, Carrabba G, Pannacci
M, Caronzolo D, Grosso S, Shinkaruk S, Colleoni F, Canron X, Tomei G, Deleris G,
Bikfalvi A.

Neurosurgery, Department of Neurological Sciences, University of Milano, Ospedale
Maggiore di Milano, Istituto di Ricovero e Cura a Carattere Scientifico, Milan,
Italy. lorenzo.bello@unimi.it

PURPOSE: We investigated the ability of the combinatorial administration of
different inhibitors with activities on glioma angiogenesis, migration, and
proliferation to produce a prolonged inhibition of glioma growth. EXPERIMENTAL
DESIGN: We combined inhibitors affecting solely tumor angiogenesis (PF-4/CTF,
cyclo-VEGI) or inhibitors affecting both angiogenesis and invasion together (PEX,
PF-4/DLR). RESULTS: When administered in combination, these drugs produced a
prolonged and increased inhibition of glioma growth independently from the type
of inhibitor used. The combinatory administration was more effective than the
administration of a single inhibitor alone, and a strong therapeutic response was
reached with a significantly lower amount of protein. The strongest inhibition
was observed when human PEX and PF-4/DLR, which affect both glioma angiogenesis
and invasion by separate mechanisms, were combined. CONCLUSIONS: This supports
the concept that prolonged glioma growth inhibition can be achieved by
simultaneous delivery of molecules that target both tumor and endothelial cells
and acting by separate mechanisms.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 15240545 [PubMed - indexed for MEDLINE]

____________________

J Neurobiol. 2004 Jul;60(1):71-88.

Evidence for a secreted chemorepellent that directs glioma cell invasion.

Werbowetski T, Bjerkvig R, Del Maestro RF.

Brain Tumour Research Centre, Montreal Neurological Institute, McGill University,
Quebec, Canada.

Secreted chemotropic cues guide the migration of neuronal and glial cell
precursors during neural development. It is not known if chemotropism contributes
to directing the invasion of brain tissue by glioma cells. A model system has
been developed that allows quantification of invasive behavior using gliomas
spheroids embedded in collagen gels. Here we provide evidence that glioma
spheroids secrete a chemorepellent factor(s) that directs cells away from the
spheroid and into the collagen matrix. The relationship between total invasion,
cell number, and implantation distance suggests that glioma cells respond to a
gradient of the chemorepellent cue(s) that is well established at 48 h. C6
astrocytoma cells normally invade the collagen at an angle perpendicular to the
spheroid edge. In contrast, an adjacent spheroid causes cells to turn away from
their normal trajectory and slow their rate of invasion. Astrocytoma cells are
repelled by an adjacent glioma spheroid but rapidly infiltrate astrocyte
aggregates, indicating that astrocytes do not express the repellent cue. Uniform
concentrations of repellent factor(s) in spheroid conditioned medium overwhelm
endogenous gradients and render glioma cells less able to exhibit this
chemotropic response. Concentration gradients of spheroid conditioned medium in
cell migration assays also demonstrate the chemorepellent cue(s)'s tropic effect.
Our findings indicate that glioma spheroids produce a secreted diffusible cue(s)
that promotes glioma cell invasion. Identification of this factor(s) may advance
current therapies that aim to limit tumor cell invasion. Copyright 2004 Wiley
Periodicals, Inc. J Neurobiol 60: 71-88, 2004

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 15188274 [PubMed - indexed for MEDLINE]

____________________

Int J Biochem Cell Biol. 2004 Jun;36(6):1046-69.

Microregional extracellular matrix heterogeneity in brain modulates glioma cell
invasion.

Bellail AC, Hunter SB, Brat DJ, Tan C, Van Meir EG.

Laboratory of Molecular Neuro-Oncology, Department of Neurosurgery,
Hematology/Oncology, Winship Cancer Institute and Brain Tumor Program, Emory
University, Atlanta, GA 30322, USA.

The invasion of neoplastic cells into healthy brain tissue is a pathologic
hallmark of gliomas and contributes to the failure of current therapeutic
modalities (surgery, radiation and chemotherapy). Transformed glial cells share
the common attributes of the invasion process, including cell adhesion to
extracellular matrix (ECM) components, cell locomotion, and the ability to
remodel extracellular space. However, glioma cells have the ability to invade as
single cells through the unique environment of the normal central nervous system
(CNS). The brain parenchyma has a unique composition, mainly hyaluronan and is
devoid of rigid protein barriers composed of collagen, fibronectin and laminin.
The integrins and the hyaluronan receptor CD44 are specific adhesion receptors
active in glioma-ECM adhesion. These adhesion molecules play a major role in
glioma cell-matrix interactions because the neoplastic cells use these receptors
to adhere to and migrate along the components of the brain ECM. They also
interact with the proteases secreted during glioma progression that degrade ECM
allowing tumor cells to spread and diffusely infiltrate the brain parenchyma. The
plasminogen activators (PAs), matrix metalloproteinases (MMPs) and lysosomal
cysteine peptidases called cathepsins are also induced during the invasive
process. Understanding the mechanisms of tumor cell invasion is critical as it
plays a central role in glioma progression and failure of current treatment due
to tumor recurrence from micro-disseminated disease. This review will focus on
the impact of microregional heterogeneity of the ECM on glioma invasion in the
normal adult brain and its modifications in tumoral brain.

Publication Types:
    Research Support, U.S. Gov't, P.H.S.
    Review

PMID: 15094120 [PubMed - indexed for MEDLINE]

 

____________________

Acta Neurochir (Wien). 2003 Nov;145(11):999-1008.

Soluble factors involved in glioma invasion.

Mueller MM, Werbowetski T, Del Maestro RF.

Division of Carcinogenesis and Differentiation, German Cancer Research Centre,
Heidelberg, Germany. ma.mueller@dkfz-heidelberg.de

Recent studies using molecular and cellular techniques of the factors regulating
the invasion process have revealed a crucial role for a number of growth factors
and cytokines. Their function lies on the one hand in the autocrine stimulation
of the tumor cells themselves, resulting in the stimulation of protease
expression and an enhancement of migratory potential. On the other hand, the
growth factors and cytokines seem to play a major role in the paracrine
activation of the tumor surrounding stroma. Through stimulation of the strong
angiogenic response that is characteristic for gliomas and also of the expression
of proteases in the stromal cells, they contribute critically to the generation
of a stromal environment that is permissive or even inductive for tumor cell
invasion. Understanding of the mechanisms by which soluble factors modulate
glioma cell invasion therefore will help to determine targets for the
modification of existing therapies and lead to the development of novel
therapeutic strategies in the management of gliomas.

Publication Types:
    Review

PMID: 14628206 [PubMed - indexed for MEDLINE]

____________________

Acta Neurochir Suppl. 2003;88:169-77.

Invasion as limitation to anti-angiogenic glioma therapy.

Lamszus K, Kunkel P, Westphal M.

Department of Neurosurgery, University Hospital Hamburg-Eppendorf, Hamburg,
Germany. lamszus@uke.uni-hamburg.de

The inhibition of tumor angiogenesis could be an efficient therapeutic strategy
for the treatment of malignant gliomas. Prominent neovascularization is induced
by these tumors, and microvascular proliferation is a malignancy grading
criterion. However, glioma cells can also invade the brain diffusely over long
distances without necessarily requiring angiogenesis. Experimentally, it was
shown that especially during early stages of growth in rodent brain, glioma cells
can coopt the preexistent host vasculature to recruit their blood supply in the
absence of neovascularization. This phenomenon was only observed in orthotopic
models in which the tumor cells were implanted into the brain which is a densely
vascularized environment, but not in subcutaneous models in which tumor cells are
implanted into a virtual space. Using an orthotopic mouse model, we analyzed
whether systemic anti-angiogenic therapy with an antibody against the vascular
endothelial growth factor receptor-2 (VEGFR-2) could inhibit intracerebral growth
of xenografted human glioblastoma cells and what effect this treatment had on
tumor morphology and invasiveness. We found that anti-angiogenic therapy
inhibited tumor growth by 80% compared to buffer-treated controls. The
intratumoral microvessel density was reduced by at least 40% in treated animals
compared to controls. However, in mice treated with the anti-VEGFR-2 antibody, we
noticed a striking increase in the number and total area of small satellite
tumors clustered around the primary mass. These satellites usually contained
central vessel cores, and tumor cells often had migrated along blood vessels over
long distances to eventually reach the surface and spread in the subarachnoid
space. Systemic anti-angiogenic therapy can thus apparently increase the
invasiveness of gliomas in the orthotopic model. Tumor cell invasion was tightly
associated with preexistent blood vessels, suggesting that increased cooption of
the host vasculature could represent a compensatory mechanism that is selected
for by inhibiting adequate tumor vascularization.

Publication Types:
    Review

PMID: 14531575 [PubMed - indexed for MEDLINE]

____________________

Neurosurg Rev. 2003 Jul;26(3):198-205. Epub 2003 Feb 12.

Proliferation, migration, and invasion of human glioma cells exposed to
fractionated radiotherapy in vitro.

Gliemroth J, Feyerabend T, Gerlach C, Arnold H, Terzis AJ.

Department of Neurosurgery, Medical University of Lübeck, Ratzeburger Allee 160,
23538, Lübeck, Germany. jan.gliemroth@t-online.de

Radiotherapy is a well established treatment for malignant gliomas. This study
describes the migration, proliferation, and invasion behaviour of two human
glioma cell lines (GaMg and U-87 Mg) grown as multicellular tumour spheroids
after radiotherapy. Migration and proliferation studies were performed using
conventional and accelerated fractionation up to 60 Gy and 59.4 Gy, respectively.
A dose-dependent growth and migratory response to irradiation independent of the
type of fractionation was observed. A coculture system in which tumour spheroids
were confronted with foetal rat brain aggregates was used for invasion studies.
Marked invasion of the glioma spheroids into the brain aggregates occurred with
or without radiotherapy. For the GaMg cells, flow cytometric DNA histograms after
treatment with 10 Gy and 40 Gy showed an accumulation of cells in the G2/M phase
of the cell cycle. Radiotherapy inhibits tumour cell growth and migration, but
the invasiveness of the remaining tumour cells seems to be unaffected.

Publication Types:
    In Vitro
    Research Support, Non-U.S. Gov't

PMID: 12845549 [PubMed - indexed for MEDLINE]

____________________

Front Biosci. 2003 May 1;8:e289-304.

Mechanisms of tumor cell invasion and angiogenesis in the central nervous system.

Visted T, Enger PO, Lund-Johansen M, Bjerkvig R.

Department of Anatomy and Cell Biology, University of Bergen, Aarstadveien 19,
N-5009, Bergen, Norway.

Despite extensive progress in characterizing the genetic events involved in the
development of gliomas, the cellular origin and the defined molecular mechanisms
that lead to their occurrence are still unclear. It is known that tumours are of
monoclonal origin. This is contrasted by the fact that gliomas frequently express
features of different glial cell lineages. With the identification of pluripotent
neural stem cells and the growth factors that control neural cell development, we
are now making early inroads towards understanding glial cell migration as well
as the neural cell plasticity within the adult central nervous system (CNS).
Gliomas share several fetal antigens with immature brain cells. It is therefore
tempting to speculate that the migration of neural precursor cells actually
represents the normal counterpart of glioma cell migration. The migratory
behavior of gliomas may be due to a predetermined interplay between normal brain
tissue and the migrating cells, where the brain represents a permissive tissue
for guiding cells with certain phenotypic traits to migrate along specific
anatomical structures. Malignant progression is also accompanied by extensive
angiogenesis which is especially prominent in glioblastoma multiforme (GBM). For
cell proliferation to take place, several cell signaling cues mediated by
specific growth factors are shared between the glioma cells and the endothelial
cells while others are unique for endothelial cells. Therefore the endothelial
cell compartment represents a promising target for novel therapeutic strategies
including gene therapy and cell-based therapies.

Publication Types:
    Review

PMID: 12700036 [PubMed - indexed for MEDLINE]

____________________

Front Biosci. 2003 Jan 1;8:e261-9.

The role of matrix metalloproteinases in glioma invasion.

Nakada M, Okada Y, Yamashita J.

Department of Neurosurgery, Division of Neuroscience, Graduate School of Medical
Science, Kanazawa University, 13-1 Takara-machi, Kanazawa, Ishikawa 920-0934,
Japan. nakada@ns.m.ksnszawa-u.ac.jp

The matrix metalloproteinase (MMP) family plays an important role in the
degradation of extracellular matrix (ECM) in various physiological and
pathological conditions. Accumulated evidence has suggested that MMPs contribute
to cancer cell invasion of the surrounding normal tissues and metastasis through
the cell-surface ECM degradation. Strong correlations have been reported between
elevated MMP levels and tumor cell invasiveness in human gliomas. Among them,
attention has been focused on gelatinases (MMP-2 and MMP-9) and membrane type
MMPs (MT-MMPs). We discuss here the biological significance of these MMPs in the
glioblastoma invasion processes. A better understanding of cell-ECM interactions
will help in developing therapeutic strategies to decrease the invasion of
gliomas.

Publication Types:
    Research Support, Non-U.S. Gov't
    Review

PMID: 12456313 [PubMed - indexed for MEDLINE]

____________________

Cancer Res. 2002 Jun 15;62(12):3335-9.

Mutant epidermal growth factor receptor up-regulates molecular effectors of tumor
invasion.

Lal A, Glazer CA, Martinson HM, Friedman HS, Archer GE, Sampson JH, Riggins GJ.

Department of Pathology, Duke University Medical Center, Durham, North Carolina
27710, USA.

The gene most commonly altered in human glioblastomas is the epidermalgrowth
factor receptor (EGFR). We profiled transcripts induced by mutantEGFR to better
understand its role in tumor progression. The pattern found suggested enhanced
tumor invasion. The highly induced genes included extracellular matrix
components, metalloproteases, and a serine protease. We confirmed that mutant
EGFR did make glioblastoma cells both more motile and invasive using in vitro
assays. Furthermore, inhibitors of EGFR (OSI-774 and Tyrphostin AG1478)
selectively down-regulated these molecular effectors in glioblastoma cells,
eliminating enhanced invasion.

Publication Types:
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, P.H.S.

PMID: 12067969 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 2002 Jan;56(2):149-58.

Proteases and the biology of glioma invasion.

Binder DK, Berger MS.

Department of Neurological Surgery, University of California, San Francisco
94143-0112, USA. dbinder@itsa.ucsf.edu

Despite optimal clinical treatment, the prognosis for malignant gliomas remains
poor. One of the primary reasons for treatment failure is not diffuse
dissemination, but local invasion. Recently, there has been an increase in
information regarding specific molecules that determine the aggressiveness and
invasion potential of high-grade astrocytic tumors. In particular, expression of
matrix metalloproteases in high-grade gliomas appears to correlate with tissue
invasiveness. It is the purpose of the present review to describe the connection
between alterations in growth-related genes, protease activity, and tumor
biology, and how these connections may suggest potential novel therapeutic
targets.

Publication Types:
    Review

PMID: 11995816 [PubMed - indexed for MEDLINE]

____________________

Neoplasia. 2001 Nov-Dec;3(6):469-79.

Bromelain reversibly inhibits invasive properties of glioma cells.

Tysnes BB, Maurer HR, Porwol T, Probst B, Bjerkvig R, Hoover F.

Department of Anatomy and Cell Biology, University of Bergen, Bergen N-5009,
Norway. bert.tysnes@pki.uib.no

Bromelain is an aqueous extract from pineapple stem that contains proteinases and
exhibits pleiotropic therapeutic effects, i.e., antiedematous, antiinflammatory,
antimetastatic, antithrombotic, and fibrinolytic activities. In this study, we
tested bromelain's effects on glioma cells to assess whether bromelain could be a
potential contributor to new antiinvasive strategies for gliomas. Several
complementary assays demonstrated that bromelain significantly and reversibly
reduced glioma cell adhesion, migration, and invasion without affecting cell
viability, even after treatment periods extending over several months.
Immunohistochemistry and immunoblotting experiments demonstrated that alpha3 and
beta1 integrin subunits and hyaluronan receptor CD44 protein levels were reduced
within 24 hours of bromelain treatment. These effects were not reflected at the
RNA level because RNA profiling did not show any significant effects on gene
expression. Interestingly, metabolic labelling with 35-S methionine demonstrated
that de novo protein synthesis was greatly attenuated by bromelain, in a
reversible manner. By using a transactivating signaling assay, we found that
CRE-mediated signaling processes were suppressed. These results indicate that
bromelain exerts its antiinvasive effects by proteolysis, signaling cascades, and
translational attenuation.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 11774029 [PubMed - indexed for MEDLINE]

____________________

J Neurooncol. 1999;44(3):223-31.

Effects of radiation on a model of malignant glioma invasion.

Bauman GS, MacDonald W, Moore E, Ramsey DA, Fisher BJ, Amberger VR, Del Maestro
RM.

Department of Radiation Oncology, London Regional Cancer Clinic, University of
Western Ontario, Canada. glenn_bauman@lrcc.on.ca

We sought to characterize the effects of radiation alone and in combination with
BCNU and dexamethasone on malignant glioma invasion. A model of malignant glioma
invasion into a gel matrix of collagen type I was used to characterize response
to radiation treatment for four malignant glioma cell lines (C6, U251, U373,
A172) and nine primary human glioblastoma explants. A radiation dose dependent
inhibition of invasion was noted for the C6 astrocytoma cell line but not the
other cell lines or explants. Addition of BCNU and dexamethasone to radiation
produced additional inhibition of invasion among the cell lines and explants but
could not suppress invasion entirely.

Publication Types:
    In Vitro

PMID: 10720202 [PubMed - indexed for MEDLINE]

____________________

J Neurosurg. 1999 Dec;91(6):989-96.

Effects of N-6 essential fatty acids on glioma invasion and growth: experimental
studies with glioma spheroids in collagen gels.

Bell HS, Wharton SB, Leaver HA, Whittle IR.

Department of Clinical Neurosciences, Western General Hospital, Edinburgh,
Scotland.

OBJECT: Intracranial infusions of gamma-linolenic acid (GLA), an essential fatty
acid, have been used as an adjuvant therapy following malignant glioma resection;
however, little is known about the dose response of glioma cells to this therapy.
In this in vitro study the authors address this important pharmacological
question. METHODS: Glioma spheroids derived from U87, U373, MOG-G-CCM, and C6
cell lines were grown in collagen gel and exposed to a range of GLA
concentrations (0-1 mM) for 5 days. The diameter of glioma spheroids was
measured, the apoptotic index was assessed using both the terminal
deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling
technique and cell morphological testing, and the levels of proliferating cell
nuclear antigen were also measured. CONCLUSIONS: The dose-response patterns were
similar for all four glioma spheroids. Low concentrations of GLA (<100 microM)
increased both apoptosis and proliferation with a net increase in tumor growth
and invasion, whereas high-dose GLA (>100 microM) significantly impaired spheroid
cell growth. The proliferative effects of low-dose GLA could be a hazard in the
clinical treatment of malignant glioma; however, because of the low toxicity of
GLA against normal cells, local delivery of millimolar doses of GLA could
significantly reduce tumor size.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 10584845 [PubMed - indexed for MEDLINE]

____________________

Neoplasia. 1999 Aug;1(3):208-19.

"...those left behind." Biology and oncology of invasive glioma cells.

Berens ME, Giese A.

Neuro-Oncology Laboratory, Barrow Neurological Institute, Saint Joseph's Hospital
and Medical Center, Phoenix, AZ 85013-4496, USA. mberens@chw.edu

Although significant technical advances in surgical and radiation treatment for
brain tumors have emerged in recent years, their impact on clinical outcome for
patients has been disappointing. A fundamental source of the management challenge
presented by glioma patients is the insidious propensity of the malignant cells
to invade into adjacent normal brain. Invasive tumor cells escape surgical
removal and geographically dodge lethal radiation exposure. Recent improved
understanding of the biochemistry and molecular determinants of glioma cell
invasion provide valuable insight to the underlying biological features of the
disease, as well as illuminating possible new therapeutic targets. Heightened
commitment to migrate and invade is accompanied by a glioma cell's reduced
proliferative activity. The microenvironmental manipulations coincident to
invasion and migration may also impact the glioma cell's response to cytotoxic
treatments. These collateral aspects of the glioma cell invasive phenotype should
be further explored and exploited as novel antiglioma therapies.

Publication Types:
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, P.H.S.
    Review

PMID: 10935475 [PubMed - indexed for MEDLINE]

____________________

Anticancer Res. 1999 Mar-Apr;19(2A):941-50.

Doxorubicin-induced cell death in highly invasive human gliomas.

Stan AC, Casares S, Radu D, Walter GF, Brumeanu TD.

Department of Microbiology, Mount Sinai School of Medicine, New York, NY
10029-6574, USA.

Glioblastoma is the most invasive form of primary brain tumors, and is often
refractory to chemotherapy. Herein, we provide evidence that two highly invasive
human glioma cell lines U-87 MG and U-373 MG, entered apoptosis after 48 hours
following 24 h growth arrest induced by Doxorubicin (10 micrograms/2 x 10(5)
cells/ml). Apoptosis depended solely on the level of intracellular drug
accumulation, and it was not related to a functional p53 tumor suppressor factor.
The multidrug resistance gene 1 (mdr-1) encoded P-glycoprotein (P-gp) was weakly
expressed in these cells upon exposure to Doxorubicin, and exerted no influence
on the extent of cellular drug efflux. Drug efflux occurred only in U-373 MG
glioma cells subsequent to physical damage of the membrane upon exposure to
Doxorubicin. Pretreatment of tumor cells with 10 micrograms/ml Doxorubicin
precluded tumor formation on the chorioallantoic membrane (CAM) of embryonated
hen eggs. Single-dose application of 0.4 microgram Doxorubicin on CAM/U-87 MG and
CAM/U-373 MG tumor transplants inhibited tumor invasion in CAM tissue by 40 to
50%. These data suggest that highly invasive glioblastomas can be driven to
apoptosis following growth arrest induced by Doxorubicin, providing that
intracellular drug accumulation suffices cytotoxic levels.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 10368637 [PubMed - indexed for MEDLINE]

____________________

Can J Neurol Sci. 1997 Feb;24(1):3-15.

Mechanisms of glioma invasion: role of matrix-metalloproteinases.

Uhm JH, Dooley NP, Villemure JG, Yong VW.

Department of Neurology & Neurosurgery, Montreal Neurological Institute, McGill
University, Canada.

One of the most lethal properties of high grade gliomas is their ability to
invade the surrounding normal brain tissue, as infiltrated cells often escape
surgical resection and inevitably lead to tumour recurrence. The consequent poor
prognosis and survival rate underscore the need to further understand and target
the cellular mechanisms that underly tumour invasiveness. Proteases which degrade
the surrounding stromal cells and extracellular matrix proteins have been
demonstrated to be critical effectors of invasion for tumours of both central and
peripheral origin. Within the nervous system, the role of metalloproteinases as
well as other classes of proteases in mediating the invasive phenotype of high
grade gliomas has been an intense area of research. We present in this article a
review of this literature and address the possibility that these proteases and
the biochemical pathways that regulate their expression, such as protein kinase
C, may represent potential targets in the therapy of high grade gliomas.

Publication Types:
    Research Support, Non-U.S. Gov't
    Review

PMID: 9043741 [PubMed - indexed for MEDLINE]

____________________

Anticancer Res. 1997 Jan-Feb;17(1A):61-9.

Cell proliferation and invasion in malignant gliomas.

Schiffer D, Cavalla P, Dutto A, Borsotti L.

Department of Neuroscience, University of Turin, Italy.

Cell proliferation and invasion were studied in sixty biopsies of malignant
gliomas selected to reproduce the spreading modalities identified in ninety
autopsy cases of glioblastoma. Cell proliferation was studied by the
immunohistochemical demonstration of PCNA and MIB-1 and by the calculation of
their labeling indexes (LI). The main finding was that cell proliferation and
cell invasion are not necessarily associated. The interface between the solid
tumor and the adjacent brain was represented either by a gradient of tumor cell
density or by a clearcut demarcation of the tumor. In the first case the LI
either did not change in the infiltration area in comparison with solid tumor or
it was much lower, whereas in the second case there was a ring with a high
density of labeled nuclei at the tumor periphery. Perineuronal satellites were
usually positive for proliferation markers. Cells accumulated in the outer
cortical layers, from a deeply located tumor, were almost negative, whereas those
originating from subarachnoidal or subpial invasion showed a high LI. High LIs
were also found in subarachnoidal and subpial growths, and in a cell population
descending into the brain parenchyma around meningeal penetrating vessels. The
relationship between cell proliferation and invasion from in vivo studies is not
a direct and a simple one.

Publication Types:
    Research Support, Non-U.S. Gov't

PMID: 9066631 [PubMed - indexed for MEDLINE]

____________________

Neurosurgery. 1997 Jan;40(1):141-51.

Inhibition of epidermal growth factor receptor-associated tyrosine kinase blocks
glioblastoma invasion of the brain.

Penar PL, Khoshyomn S, Bhushan A, Tritton TR.

Division of Neurosurgery, University of Vermont College of Medicine, Burlington,
USA.

OBJECTIVE: Glioblastoma multiforme is a malignant primary brain tumor associated
with short patient survival despite aggressive treatment, in part because of its
propensity to aggressively infiltrate into brain tissue. Glioblastoma multiforme
is also unique because it is the only nonepithelial human tumor for which
excessive activation of epidermal growth factor receptor (EGFR) has been
consistently linked to tumor growth and patient survival, and EGFR activation
promotes glioblastoma multiforme infiltration in vitro. METHODS: Cocultures of
human glioblastoma spheroids (derived from three separate patients) and fetal rat
brain aggregates were examined for infiltration using confocal microscopy, in the
presence of 0 to 100 mumol/L genistein, a tyrosine kinase (TK) inhibitor, and 3
mumol/L tyrphostin A25, a specific EGFR-TK inhibitor. RESULTS: Infiltration (not
attachment) was completely inhibited by genistein at 10 mumol/L, the IC20 for
monolayer growth inhibition in two cell lines. Tyrphostin A25 at 3 mumol/L (the
IC20 for monolayers) reduced invasion in a third cell line from 38.8 +/- 6.1%
invasion-hour per hour (n = 5) to 2.9 +/- 1.2% invasion-hour per hour (n = 6) (P
= 0.0002, two-tailed t test, 93% inhibition), and from 0.54 +/- 0.065% per hour
(slope) to 0.028 +/- 0.018% per hour (P = 0.00001, 95% inhibition). Maximal
percent invasion was reduced from 100 +/- 0 to 7.4 +/- 5.6% of the fetal rat
brain aggregate. No change was detected in EGFR-associated tyrosine
phosphorylation at those doses in monolayers by 32P immunolabeling, consistent
with the known effects of low concentrations of TK inhibitors. An increase in
expression of wild-type and truncated EGFR was demonstrated by Western blotting.
Invasion was equally well inhibited by a monoclonal antibody to the high-affinity
ligand binding domain of EGFR and not by antibody to an inactive domain.
CONCLUSION: Our observations support the role of EGFR activation as a determinant
by which glioblastoma invades normal brain tissue, and we show that invasion can
be effectively inhibited at much lower concentrations of TK inhibitors than are
necessary for growth suppression.

PMID: 8971836 [PubMed - indexed for MEDLINE]

____________________

Anticancer Res. 1996 Sep-Oct;16(5A):2917-22.

Hyaluronic acid facilitates glioma cell invasion in vitro.

Nakagawa T, Kubota T, Kabuto M, Kodera T.

Department of Neurosurgery, Fukui Medical School, Japan.

We investigated the effects of hyaluronic acid (HA) on the invasiveness of three
human glioma cell lines (A172, T98G and U251) and their secretion of matrix
metalloproteinases (MMPs), plasminogen activators (PAs), and hyaluronidase. The
invasion of all three glioma cell lines was enhanced by the impregnation of
Matrigel with HA in an in vitro invasion assay using 12 microns porosity
polycarbonate filter transwells. The secretion of MMPs and PAs was not influenced
by the presence of HA. Hyaluronidase activity was not detected in the culture
media of any glioma cell line. HA also enhanced the motility of A172 and U251
glioma cells, but did not influence the motility of T98G glioma cells. The
adhesion and spreading of all glioma cell lines were inhibited on HA-coated
plates. HA, however, did not influence the proliferation of any of the glioma
cell line. These results suggest that the presence of HA contributes to glioma
cell invasion, which involves the stimulation of detachment and motility of
glioma cells and the maintenance of proteinase secretion by glioma cells.

PMID: 8917407 [PubMed - indexed for MEDLINE]

____________________

Neurosurgery. 1996 Aug;39(2):235-50; discussion 250-2.

Glioma invasion in the central nervous system.

Giese A, Westphal M.

Department of Neurosurgery, University Hospital Eppendorf, Hamburg, Germany.

Invading glioma cells seem to follow distinct anatomic structures within the
central nervous system. Tumor cell dissemination may occur along structures, such
as the basement membranes of blood vessels or the glial limitans externa, that
contain extracellular matrix (ECM) proteins. Frequently, invasive glioma cells
are also found to migrate along myelinated fiber tracts of white matter. This
behavior is most likely a consequence of using constitutive extracellular ligands
expressed along the pathways of preferred dissemination. The extracellular space
in anatomic structures, such as blood vessel basement membranes or between
myelinated axons, is profoundly different, thus suggesting that glioma cells may
be able to use a multiplicity of matrix ligands, possibly activating separate
mechanisms for invasion. In addition, enzymatic modification of the extracellular
space or deposition of ECM by the tumor cells may also create a more permissive
environment for tumor spread into the adjacent brain. Tumor cell invasion is
defined as translocation of neoplastic cells through host cellular and ECM
barriers. This process has been studied in other cancers, in which a cascade of
events has been described that involves receptor-mediated matrix adhesion,
degradation of matrix by tumor-secreted metalloproteinases, and, subsequently,
active cell locomotion into the newly created space. Although some of these
mechanisms may play an important role in glioma invasion, there are some
significant differences that are mainly the result of the profoundly different
composition of the extracellular environment within the brain. This review
focuses on the composition of central nervous system ECM and the recent evidence
for the use by glioma cells of multiple invasion mechanisms in response to this
unique environment.

Publication Types:
    Research Support, Non-U.S. Gov't
    Review

PMID: 8832660 [PubMed - indexed for MEDLINE]

____________________

Cancer Res. 1990 Sep 15;50(18):6039-44.

Effect of epidermal growth factor on glioma cell growth, migration, and invasion
in vitro.

Lund-Johansen M, Bjerkvig R, Humphrey PA, Bigner SH, Bigner DD, Laerum OD.

Gade Institute, Department of Pathology, University of Bergen, Haukeland
Hospital, Norway.

Effects of epidermal growth factor (EGF) and an antibody (Ab-528) reactive
against the binding site for EGF on human EGF receptors were studied on
multicellular tumor spheroids obtained from three human glioma cell lines with
high (D-37 MG), medium (D-247 MG), and low (D-263 MG) levels of EGF receptor
expression. The D-247 MG and D-263 MG spheroids grew slowly or not at all in the
absence of EGF, while in the presence of EGF they were growth stimulated. Tumor
cell migration, as measured by the spread of cells from spheroids on a plastic
substratum, was increased by the addition of EGF for all three cell lines.
Stimulation of migration could be blocked by a subsequent addition of Ab-528 to
the medium at a concentration of 50 micrograms/ml. Invasiveness of glioma cell
spheroids into fetal rat brain aggregates was related to EGF receptor expression;
the two lines with medium to high receptor expression (D-247 MG and D-37 MG) were
invasive, while the line with low EGF receptor expression (D-263 MG) was
noninvasive, as assessed by an in vitro coculture assay. In the D-247 MG cell
line, morphometry revealed EGF-enhanced invasiveness of the tumor cells. The
addition of the Ab-528 to EGF-treated cocultures reduced invasion in both D-247
MG and D-37 MG cell lines. Antibody Ab-528 alone did not affect glioma cell
growth or migration but did inhibit invasiveness. The present study suggests
that, in brain tumors with an increased number of normal-sized Mr 170,000 EGF
receptors, EGF or an EGF-like ligand such as transforming growth factor-alpha may
selectively facilitate expansive tumor growth and tumor cell invasion. This
effect may in part be blocked or retarded by specific antibodies to the EGF
receptor.

Publication Types:
    Research Support, Non-U.S. Gov't
    Research Support, U.S. Gov't, P.H.S.

PMID: 2393868 [PubMed - indexed for MEDLINE]