摘要Background Estrogen receptor (ER)-negative breast cancer cells are more aggressive than ER-positive cells. Elevated levels of cyclooxygenase-2 (COX-2) and vascular endothelial growth factor-C (VEGF-C) expression have been detected in cultured human breast cancer cells and are associated with negative hormone receptor status. In this study, we created ERα stable transfectants in MDA-MB-231 cells to explore the effect of ERα on cell growth and COX-2 and VEGF-C expression.Methods The green fluorescent protein (GFP)-ERα plasmids were stably transfected into ER-negative MDA-MB-231 cells. The proliferation and migration of untransfected MDA-MB-231 cells, ERα-transfected MDA-MB-231 cells and ER-positive MCF-7 cells were determined. The expression of COX-2, and the levels of VEGF-C mRNA and the VEGF-C secretion concentration were assayed in these cell lines.Results The proliferation and migration capacities of ERα-tranfected MDA-MB-231 cells were significantly decreased (P <0.05). The expression of COX-2 was significantly lower in ERa-tranfected MDA-MB-231 cells than in untranfected MDA-MB-231 cells. The mRNA and protein levels of VEGF-C were lower in ERa-tranfected MDA-MB-231 cells than in untransfected MDA-MB-231 cells (P<0.05).Conclusions ERα stable transfection inhibits proliferation and migration capacities of MDA-MB-231 cells and decreases expression of COX-2 and VEGF-C. The decreases of proliferation and migration capacities may be related to suppression of COX-2 and VEGF-C expression.