Figure 4. MCF7-Y537S cells are resistant to the pro-apoptotic effects of 4-OHT. Briefly, the transduced MCF7 cell lines were all plated in 6-well plates. On the next day, the cells were treated with 4-OHT (1 µM) for 72 hours. MCF7-EV cells were processed in parallel, as a negative control. Bar-graphs were used to summarize the overall results. Note that annexin V levels were increased in all transfected cell lines; however, MCF7-Y537S cells were specifically resistant to the pro-apoptotic effects of 4-OHT. * p<0.05. In contrast, no changes in Annexin V levels were observed in all transfected cells, in the absence of 4-OHT (1 µM); ns = not significant. (Panel A) Treated (RED) vs. Untreated (BLUE); (Panel B) Untreated; (Panel C) Treated with 4-OHT.