Assessment of the Synergic Effect of Avastin and VEGF Sirna on Inhibition of Cell Proliferation and Angiogenic Factor Expression of Human Breast Cancer Cells

Abstract Angiogenesis is an important process in tumor growth and metastasis and vascular endothelial growth factor (VEGF) plays an important role in this process. Several VEGF inhibitors have been developed as anticancer agents including humanized monoclonal antibodies, and various small molecules. The aim of this work was to investigate the effect of combination of VEGF siRNA and Avastin on breast cancer MCF-7 cell line behavior. For this purpose, the cells were treated with different concentrations of Avastin and/or VEGF siRNA and their combination. The cell survival and cell proliferation were assayed by cell counting, trypan blue and MTT tests. The cell migration was assayed by scratching test. VEGF expression was assayed by RT and real-time PCR and ELISA methods. Results indicated the significant increase in cell death following treatment with Avastin (50% cell death at 100 µg/ml). Cell death with VEGF siRNA transfection was lower than Avastin, however, it was significant. This result in VEGF siRNA + Avastin (100 µg/ml) treatment was greater compared to treatment with each of these compounds alone (47%). Scratching results also showed the synergic effect of VEGF siRNA and Avastin (57% decrease). Real-time PCR results showed that Avastin at concentrations of ≥ 50 µg/ml led to 2.5 to 7.5-fold decrease in VEGF expression levels. Also, treatment with VEGF siRNA led to 15.5-fold decrease in VEGF expression. Finally, VEGF expression following VEGF siRNA + Avastin treatment led to a significant 47.5-fold decrease in VEGF expression. It could be concluded that combination of VEGF siRNA and Avastin have a more significant impact on the inhibition of cell growth and migration and it can probably be used as an effective therapeutic approach.