siRNA Inhibition of ER-α Expression Reduces KGF-induced Proliferation of Breast Cancer Cells

Background: Keratinocyte growth factor (KGF) produces a rapid increase in the proliferation and motility of estrogen receptor (ER)-positive breast cancer cells which is abolished by estrogen deprivation and/or anti-estrogen treatment. The present study examined the hypothesis that ER-α is involved in the KGF proliferation in MCF-7 cancer cells using small interfering RNA (siRNA) to selectively inhibit ER-α expression. Materials and Methods: At 48 hours following ER-α siRNA transfection, the MCF-7 cells were treated with KGF (50 ng/ml) or vehicle for 24 hours. Cell proliferation was measured using a MTT assay. ER-α protein levels were quantified by Western blotting. Results: ER-α siRNA transfection significantly reduced ER-α expression and MCF-7 cell proliferation. KGF-mediated enhancement of cell proliferation and motile cell morphology were reduced or absent in the siRNA transfected MCF-7 cells. Conclusion: ER-α expression is associated with KGF-induced proliferation of breast cancer cells.