Figure 3.

MST4 protects pituitary cells from hypoxia-induced apoptosis. A, Overexpression of MST4 decreases hypoxia-induced apoptosis. MST4 or control cells were exposed to 1% O₂ for 17 hours, and apoptosis was assessed by TUNEL staining (white arrows). Bar, 20 μm. B, Rates of apoptosis were expressed as percentages of TUNEL-positive cells to total cells (n = 3). C, p38MAPK and AKT mediate protective effects of MST4. In the presence of SB203580 (10 μM), LY294002 (10 μM), and PD98059 (30 μM), cell death was measured by TUNEL after exposure to 1% O₂ for 17 hours. In the upper panel, images represent TUNEL positive staining, and the rates of apoptosis were expressed as percentages of TUNEL cells to total cells (n = 3). Bar, 20 μm. **, P < .01, MST4 cells compared with vector control cells; †, P < .001, rates of apoptosis of vector cells at 7 and 17 hours of hypoxia compared with 0 hours, respectively; #, P < .01, inhibitor-treated MST4 cells compared with DMSO vehicle treatment. DAPI, 4′,6′-diamino-2-phenylindole.