Figure 4

mTOR and PI3K inhibition promotes survivin expression in TSC2^−/− cells. Twenty-four h after plating, the cells were incubated with rapamycin (Rapa, 100 ng/mL) or LY294002 (LY, 10 µM) for 48 h. A: Western blot detection of survivin and procaspase-3 expression. Under control conditions, the TSC2^−/− A⁺ cells did not express detectable levels of survivin, which only became apparent after mTOR and PI3K blockade; procaspase-3 was expressed under all experimental conditions. The R⁺ and A549 cells show survivin and procaspase-3 expression under all experimental conditions. B: Immunocytochemical detection of survivin. The A⁺ cells became positive to antibody labeling after exposure to rapamycin and LY. C: Twenty-four h after plating in specific standard medium, VSMC cells were treated with rapamycin (100 ng/mL), LY (100µM), wortmannin (W, 320 nM) and staurosporine (St, 1 µM) for 48 h, and survivin and procaspase-3 expression was assessed by means of Western blotting. The VSMCs showed the expression of procaspase-3, but not survivin.