Figure 1

TamR cells are resistant to Tamoxifen. a: TamR cells were larger, flatter and exhibited a more mesenchymal phenotype than the parental cell line MCF7. 10X magnification. b: MTT proliferation assays were performed on parental MCF7 cells and TamR cells treated with increasing doses of Tamoxifen(0.0–15.0 μM) over 24 hours. 50% DMSO was used as a control as it is known to eliminate cells independent of ER status. TamR cells were successfully selected for acquired Tamoxifen resistance from its parental cell line MCF7 as they continued to proliferate in Tamoxifen concentrations, 5 μM, 7.5 μM, 10 μM, 11.5 μM and 13.5 μM, that eliminate MCF7 cells. Graph represents the average cell proliferation in percentage of 10 replicates with standard deviation represented by error bars. *** P<0.001. Abbreviation: Dimethyl sulfoxide (DMSO). c: mRNA expression of ER and HER2 was measured using qPCR. Graph represents the mRNA fold-regulation values of TamR cells relative to MCF7 cells, normalized against three housekeeping genes with standard deviation of triplicate experiments represented by error bars** P<0.01. Abbreviations: Estrogen receptor alpha (ER), Human Epidermal Growth Factor Receptor 2 (HER2).