VEGF and TGF-β1 are cytokines that stimulate tissue invasion and angiogenesis. These factors are considered as molecular targets for the therapy of glioblastoma. Bevacizumab, a recombinant humanized monoclonal antibody developed against VEGF, inhibits endothelial cell proliferation and vessel formation. Flavonoids obtained from Dimorphandra mollis and Croton betulaster have been described as proliferation inhibitors of a human glioblastoma derived cell line. VEGF and TGF-β1 levels were dosed by ELISA in a GL-15 cell line treated with bevacizumab and also with the flavonoids rutin, 5-hydroxy-7,4'-dimethoxyflavone, casticin, apigenin and penduletin. Rutin reduced the VEGF and TGF-β1 levels after 24 h but not after 72 h. The other flavonoids significantly reduced TGF-β1 production. Bevacizumab reduced only the VEGF levels in the supernatant from GL-15 cultures. These results suggest that the flavonoids studied, and commonly used in popular medicine, present an interesting subject of study due to their potential effect as angiogenic factor inhibitors.

Neural precursor differentiation from mouse ES (embryonic stem) cells have been demonstrated using EB (embryoid body), co-culture on stromal feeder layers, and in the absence of external inducing signals. Most of available mouse ES cell original research articles have worked with only six different cell lines. Our goals were to isolate one new mouse ES lineage, and perform a detailed immunocytochemistry study during neural differentiation, making use of an EB strategy protocol following the generation of neural progenitors, glial cells and postmitotic neurons. The dynamics of differentiation of ES cell derived neuronal precursors into differentiated glia cells and neurons were followed in vitro and correlated to exposure to specific elements of feeder medium. Morphological aspects of generated cellular types, including its immunocytochemical expression of differentiation markers were studied. Immuno-positivity against β-III tubulin, PGP and TH (tyrosine hydroxylase) was observed from stage I. Approximately 80% of cells were positive for TH at stage I. The first glial cell type appears in stage III. TH, PGP or β-III tubulin-positive cells with neuronal typical morphology only being seen in stage III when TH-positive cells corresponded to approximately 12% of total cells. Variations among other literature findings can be explained by the choice we made to use a newly isolated ES cell line. As colonies may behave differently during neuronal differentiation, it reinforces the necessity of studying original ES cell lines.

12532 Background: Malignant gliomas are typically angiogenic and express greater amounts of angiogenic factors. Vascular endothelial growth factor (VEGF) and platelet derived growth factor (PDGF) are prominent glioblastoma-associated multifunctional cytokines that stimulate migration, invasion and angiogenesis. Their receptor inhibiton is considered an important target for anitumoral therapy. Flavonoids obtained from Dimorphandra mollis and Croton betulaster, native medicinal plants from Bahia-Brazil, have been described as proliferation inhibitors of a human glioblastoma derived cell line and reduce VEGF production by GL-15. In this study, VEGF and PDGF receptors expression by GL-15 cultures treated with bevacizumab and flavonoids were evaluated. Methods: GL-15 cultures were treated or not with pendulitin and rutin flavonoids (100μM) and bevacizumab (1μg/mL). After 24 hours VEGF and PDGF receptors were analyzed by flow cytometry using monoclonal antibodies labeled with FITC. Results: Flow cytometry showed that the GL-15 cells expressed PDGFR alfa (10%), PDGFR beta (52%), VEGFR 1 (26%) and VEGFR 2 (95%). It was observed that the pendulitin and rutin flavonoids treated cells showed a reduction on PDGFR alfa expression (2 and 1,6 % respectively) but the other receptors expression was similar to the non-treated or DMSO treated controls. Conclusions: GL-15 human glioblastoma derived cell line expresses receptors to the angiogenic cytokines studied. VEGFR 2 expression was predominant and bevacizumab didn’t alter the receptors production. Flavonoids extracted from D. mollis and C. betulaster seem to have an inhibitory action on the PDGRF alfa expression but not on the others receptors. No significant financial relationships to disclose.