Effect of Estrogen, Tamoxifen and Epidermal Growth Factor on the Transcriptional Regulation of Vascular Endothelial Growth Factor in Breast Cancer Cells

Abstract

Background: VEGF (Vascular Endothelial Growth Factor) is a key factor of angiogenesis and high tissue VEGF levels are related to a poor prognosis in breast cancer. Materials and Methods: By semi-quantitative RT-PCR, we determined the relative expressions of VEGF mRNA in MCF-7 (both ER-α+ and ER-β+ (mainly ER-α+), PR+, bcl-2+, EGFR-) and MB-MDA-231 (only ER-β+, PR-, EGFR-) breast cancer cells which were treated with estrogen, tamoxifen and EGF (Epidermal Growth Factor). Results: In MCF-7 cell lines, estrogen induced the expression of VEGF mRNA while tamoxifen reduced its expression. Estrogen and tamoxifen did not confer any significant effect on MB-MDA-231 cells and EGF showed no significant effect on MCF-7 or MB-MDA-231. Conclusion: Reduced VEGF mRNA expression of MCF-7 cells treated with tamoxifen may be related to the antagonistic effect of tamoxifen on ER-positive breast cancer, and this antagonistic effect may be related to ER-α.