Figure 4. ONC201 activates an integrated stress response, decreases cyclin D1 expression, and causes an accumulation of cells in G1 in TNBC cells sensitive to the compounds anti-proliferative effects.
A) Western blot analysis of MDA-MB-231 cells for EIF2α phosphorylation, ATF4 expression, and cyclin D1 expression and following treatment with a vehicle control, 5 μM, or 10 μM ONC201 for 72 hours. Densitometry was performed using NIH ImageJ software. The ratio represents the intensity of the phospho-EIF2α band divided by the intensity of the total EIF2α band. B) Quantification of cells in G0/G1, S, and G2 phases of the cell cycle using flow cytometric analysis of propidium iodide stained MDA-MB-231 cells at 24 and 48 hours following treatment with a vehicle control or 10 μM ONC201. ns: p≥0.05; *p≤0.05, **p≤0.01, ***p≤0.001, ****p≤0.0001.