Fig 1: Expression of nuclear transport signature genes are stimulated by 4-OH-TAM in ERα (+) breast cancer cells.A, ERα ligands increase mRNA expression of signature genes in MCF-7 cells. MCF-7 cells were treated with 10 nM E2 or 1 μM 4-OH-TAM for 24 hours. Total RNA was isolated and mRNA expression of signature genes were analyzed using qPCR. B, ERα recruitment to gene-regulatory regions of nuclear transport signature genes upon tamoxifen treatment in MCF-7 cells or in MCF-7 TAM R cells. Dendograms for ERα occupancy in MCF-7 TAM R cells (black) and MCF-7 cells that are treated with 4-OH-TAM (blue) from the University of California, Santa Cruz, Santa Cruz, California) genome browser. BED files are obtained from another report 4). C, Protein expression of nuclear transport signature genes are increased with ligand treatment in MCF-7 cells and MCF-7 TAM R cells. Western blot analysis of XPO1, RANGAP1, NUP205, NUP153, and KPNA2 and ERK2 as the loading control for MCF-7 parental cells or MCF-7 TAM R cells that were kept in media with 4-OH-Tam for indicated times. The experiment was repeated three times. Representative results are shown. D, Comparison of signature gene expression in different cell lines. ERα (+) MCF-7, T47D, BT474, MDA-MB-134, and HCC-1500 cells were cultured as described. Western blot analysis of XPO1, RANGAP1, NUP205, NUP153, and KPNA2 and β-actin as the loading control for all cell lines was performed. Representative results from the Western blot analysis are shown. The experiment was repeated three times. Signal from each antibody is calculated and normalized relative to the β-actin signal. Level of proteins in cell lines is reported relative to MCF-7 cells. For proteins that increase in tamoxifen-resistant cells relative to MCF-7 cells average relative expression and SEM is plotted. Ctrl, control.