Disruption of intracerebral progression of C6 rat glioblastoma by in vivo treatment with anti-CD44 monoclonal antibody.
ABSTRACT Glioblastoma multiforme (GBM) invasiveness is a complex process that involves recognition and attachment of GBM cells to particular extracellular matrix (ECM) molecules before migrating into proteolytically modified matrix and inducing angiogenesis. The CD44 molecule, which is a transmembrane adhesion molecule found on a wide variety of cells including GBM, has been suggested as the principal mediator of migration and invasion. The aim of the present study was to demonstrate whether an antibody specific to the standard form of CD44 (CD44s, 85-90 kD) might prevent invasion and thus disrupt progression of C6 GBM in vivo.
Immunostaining demonstrated homogeneous expression of CD44s on the surface of C6 GBM cells and tumors. Flow cytometric analysis demonstrated binding saturation of anti-CD44s monoclonal antibody (mAb) to the receptor at 1 microg/5 x 10(5) cells. Blocking of CD44s in vitro resulted in a dose-dependent progressive (up to 94+/-2.7%; mean +/- standard deviation [SD]) detachment of C6 cells from ECM-coated culture. Blocking of CD44s in vivo resulted in significantly reduced C6 brain tumors (3.6+/-0.4% [SD])--measured as the quotient: tumor surface (mm2)/brain surface (mm2) x 100--compared with untreated (19.9+/-0.9%) or sham-treated (19.2+/-1.1 to 19.3+/-2.5% [SD]) rats. Disruption of C6 GBM progression correlated with an improved food intake; treated rats were significantly less cachectic (166.6+/-16.4 g [SD]) than those that were untreated (83+/-2.7 g [SD]) or sham-treated (83.4+/-1.1 to 83+/-2.2 g [SD]) rats.
The authors conclude that CD44s-targeted treatment with specific mAb may represent an effective means for preventing progression of highly invasive GBMs.
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ABSTRACT: Therapeutic efforts for human glial tumors have over the past years been redirected towards a compartmental treatment concept. The diffusely infiltrative nature of the disease calls for therapeutic agents to reach single cells far beyond the focus of attention which present therapies like surgery and radiation are able to treat. Specific drug discovery approaches which seek to define targets which are specific for gliomas have generated therapeutic options which allow for a highly selective development of new reagents. Combined with new modalities for compartmental drug delivery, systemic complications might be reduced and advantage taken of a compartmental specificity of a target which otherwise in the context of systemic application would not be as specific or burdened with side effects. From the present status of therapeutic developments in neuro-oncology it can be expected that a sufficient number of drug targets emerge which can be exploited by means of interstitial or intracavitary delivery, which are not neurotoxic and which may even be imaged in their action with the new metabolic imaging modalities. Convection enhanced delivery, conditionally replicating oncolytic viruses and motile, genetically engineered neural stem cells all seem to fulfill the distribution requirements which an effective therapeutic for gliomas will need to overcome the very limited efficacy which surgery, conventional chemotherapy and radiation have to offer. Whereas the genomics based discovery approaches are not specific for neuro-oncology, the development of delivery strategies is highly specific for the central nervous system, thus creating a unique set of organ and disease specific therapies.Journal of Neuro-Oncology 12/2004; 70(2):255-69. · 3.21 Impact Factor
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ABSTRACT: This study examines the functional relationship between glioma cell production of hyaluronan (HA), known to play a role in glioma invasion, expression of its CD44 receptor, and glioma cell viability. Production of HA by CD44 positive mouse G26 and human U373 glioma cell lines was evaluated and compared to that of a CD44 positive mouse fibroblast-like L929 cell line. We found that both G26 and U373 MG glioma cells, but not L929 fibroblast-like cells, synthesized HA. The synthesis of HA by glioma cells was found during the proliferative phase as well as post-confluency, as detected by fluorophore-assisted carbohydrate electrophoresis. Eighty to ninety percent of the HA synthesized was secreted into the medium and 10-20% remained associated with the cells. To examine a possible mechanistic link between the CD44-HA interaction and endogenous HA production, glioma cells were treated with either anti-CD44 antibodies (clones KM201 or IM7) or HA oligosaccharides (hexamer oligoHA-6 or decamer oligoHA-10). We found that oligoHA-10, which was previously shown to compete effectively with the CD44-HA interaction, enhanced glioma HA synthesis by approximately 1.5-fold, without affecting cell viability. IM7 treatment of human U373 glioma cells resulted in over 50% decrease of HA production, which was associated with changes in cell size and apoptosis. Taken together, these data show that CD44 specific ligands, such as the IM7 antibody or oligoHA-10 could down-regulate or up-regulate glioma HA production, respectively. Our results suggest that interference with CD44/HA may lead to the discovery and development of new treatment modalities for glioma.International Journal of Cancer 12/2009; 127(3):532-42. · 5.44 Impact Factor
Article: Glioma Cell Motility is Associated with Reduced Transcription of Proapoptotic and Proliferation Genes: A cDNA Microarray Analysis[show abstract] [hide abstract]
ABSTRACT: Microarray analysis of complementary DNA (cDNA) allows large-scale, comparative, gene expression profiling of two different cell populations. This approach has the potential for elucidating the primary transcription events and genetic cascades responsible for increased glioma cell motility in vitro and invasion in vivo. These genetic determinants could become therapeutic targets.We compared cDNA populations of a glioma cell line (G112) exposed or not to a motility-inducing substrate of cell-derived extracellular matrix (ECM) proteins using two sets of cDNA microarrays of 5700 and 7000 gene sequences. The data were analyzed considering the level and consistency of differential expression (outliers) and whether genes involved in pathways of motility, apoptosis, and proliferation were differentially expressed when the motility behavior was engaged. Validation of differential expression of selected genes was performed on additional cell lines and human glioblastoma tissue using quantitative RT-PCR.Some genes involved in cell motility, like tenascin C, neuropilin 2, GAP43, PARG1 (an inhibitor of Rho), PLC, and CD44, were over expressed; other genes, like adducin 3 and integrins, were down regulated in migrating cells. Many key cell cycle components, like cyclin A and B, and proliferation markers, like PCNA, were strongly down regulated on ECM. Interestingly, genes involved in apoptotic cascades, like Bcl-2 and effector caspases, were differentially expressed, suggesting the global down regulation of proapoptotic components in cells exposed to cell-derived ECM. Overall, our findings indicate a reduced proliferative and apoptotic activity of migrating cells. cDNA microarray analysis has the potential for uncovering genes linking the phenotypic aspects of motility, proliferation, and apoptosis.Journal of Neuro-Oncology 05/2001; 53(2):161-176. · 3.21 Impact Factor