Investigation of anti-angiogenic and anti-apoptotic effects of Bevacizumab in breast cancer cell line

Tumor angiogenesis is a complex mechanism consisting of multi-step events including secretion or activation of angiogenic factors by tumor cells, activation of proteolytic enzymes, proliferation and migration of endothelial cells. VEGF may be the rate limiting factor in the tumor-related switch to an angiogenic phenotype that is critical for growth and metastasis. Current approaches to target angiogenesis rely on inhibiting growth factors that stimulate vascular endothelial cells or blocking their receptors. VEGF has become a major target of investigation in this area. Bevacizumab is a monoclonal antibody developed against VEGF. Enhanced COX2-induced synthesis of prostaglandins stimulates cancer cell proliferation, promotes angiogenesis, inhibits apoptosis, and increases metastatic potential. In the present study, we aimed to investigate the antiangiogenic and apoptotic effect of Bevacizumab on MDA-MB-231 cell line and changes of VEGF-A, VEGF-C, VEGFR2 and COX-2 mRNA expressions. In our study, cell viability was detected in the MDA-MB-231 cells by XTT assay method and acridin-orange/ethidium bromide staining, for different dosages and incubation time, following Bevacizumab treatment. Quantitative Real-Time PCR method was used for analysis of mRNA expression levels of VEGF-A, VEGF-C, VEGFR2 genes which take part in same signal pathway and COX-2 acting on this pathway. In this study, although COX-2 mRNA expression was higher in breast cancer cells at 24 and 48h, its expression level was low in MDA-MB-231 at 72 and 96h after the 50 ?g/ml dose. VEGF-A, VEGF-C and VEGFR2 mRNA expression level and invasion ability of MDA-MB-231 cells significantly increased at 24, 48 and 72h in a dose dependent manner. VEGF-A, VEGF-C and VEGFR2 mRNA expression and invasion ability of MDA-MB-231 significantly decreased at 96h in a dose dependent manner. Our data suggest that the long-term application of bevacizumab is required for the suppression of angiogenic properties.