Regulation of apoptosis by androgens in prostate cancer cells.

The balance between proliferation and cell death is often disrupted in cancer leading to tumor growth. In prostate cancer, these events are regulated, at least in part, through androgen signaling. Prostate cancer is dependent on androgens for growth in the initial stages where apoptosis is simultaneously inhibited. Androgen signaling remains important in later stages of prostate cancer as well. Here, we provide methods to study apoptosis in prostate cancer cells and its regulation by androgens. In prostate cancer cells grown in vitro, apoptosis can be induced by different stimuli, such as the endoplasmic reticulum Ca2+ ATPase inhibitor Thapsigargin (TG) through the intrinsic apoptosis pathway, or tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) plus the inhibition of PI3K, through the extrinsic signaling pathway; both of these apoptotic events can be blocked by androgens. Here, we provide protocols to assess apoptosis triggered by TG or TRAIL plus PI3K inhibitor LY294002, in prostate cancer cells in vitro using nuclear fragmentation and TUNEL assays aided by fluorescence microscopy or flow cytometry.