Dual kinase inhibitor Lapatinib downregulates ER-α36 expression and sensitizes MCF7/TAM cells to tamoxifen.

<p>A. Western blot analysis of the expression of ER-α36 and 66 as well as EGFR and HER2, and levels of EGFR and HER2 phosphorylation in parental MCF7 (MCF7/P) and MCF7/TAM cells treated with indicated concentrations of Lapatinib for 12 hours. B. Cells were treated with indicated concentrations of TAM together with vehicle or 1 µM of Lapatinib (LAP) for seven days and the numbers of survived cells were counted. The columns represent the means of three experiments; bars, SE. *, P<0.05 for MCF/TAM cells treated with vehicle vs cells treated with 1 µM of tamoxifen and Lapatinib.