siRNA‐Mediated Down‐regulation of Vascular Endothelial Growth Factor in MCF‐7 cells

Vascular endothelial growth factor (VEGF) promotes angiogenesis and vascularization. Inhibition of angiogenesis results in tumor regression. VEGF induces endothelial cell proliferation, promotes cell migration, and inhibits apoptosis. Deregulated VEGF expression contributes to angiogenesis and tumor growth and the etiology of several other diseases that are characterized by abnormal angiogenesis. VEGF family of genes include VEGF‐A, VEGF‐B, VEGF‐C and VEGF‐D. To investigate targeted degradation of VEGF mRNA using short interference RNA (siRNA) as a means to inhibit VEGF expression, MCF‐7 human breast cancer cells were transfected with phosphothioester siRNAs designed to degrade VEGF mRNAs. RNA was extracted by NP‐40 lysis method and analyzed by Reverse Transcription‐Polymerase Chain Reaction (RT‐PCR) and Northern blotting. Western blot analysis was performed on whole cell lysates. RT‐PCR and Northern blot analysis showed siRNA‐mediated degradation of VEGF mRNA. Western blot analysis showed a corresponding decrease in the expression of VEGF. The above results indicate the potential use of siRNA for the down regulation of VEGF expression and consequently cause tumor regression. This work was supported by science research funds from Arnold and Marie Schwartz College of Pharmacy, Long Island University, Brooklyn, NY.