Figure 8.

Protesterone (P₄) induced cell death of the MDA-MB-231 cells. MDA-MB-231 cells were transfected with the scrambled (Mock) or the small hairpin siRNA against the progesterone receptor membrane component 1 (shPGRMC1) plasmids for 48 h. After confirmation of the efficiency of the silencing protocol by Western blotting, cells were cultured for an additional 24 h in the absence or presence of P₄ (1 μM). Following this, cells were incubated on the day of the experiment with 4 μM of propidium iodide (PI) for 45 min at 37 °C inside the incubator. Cell images were acquired at 555/624 nm of wavelength (excitation/emission, respectively), by using a 40× objective mounted in a fluorescence microscope. The percentage of positive PI loaded cells with respect to the total counted cells in the fields was estimated, considering the mean ± Standard error of the mean (S.E.M.) of 3–4 independent experiments, and was represented in the bar chart. ***: represents p < 0.001 with respect to the mock resting cells; meanwhile, ^$$$: represents p < 0.001 with respect to the cells expressing PGRMC1 and treated with P₄. The bar in the images represents 50 μm.