AST acts by modulation of PI3K/Akt/mTOR signaling but does not involve the MAPK pathway. HCT 116 cells were treated with AST (80 μg/ml) and Western blotting was performed to analyze the level of (A) PTEN, p-Akt, Akt, p-mTOR, mTOR and (B) p-JNK, JNK, p-p38 and p38 in a 72-hour time course study. (C) Combined effects of AST and rapamycin on the pro-angiogenic factors bFGF and VEGF. HCT 116 cells were incubated with AST (80 μg/ml) either in the absence or presence of the mTOR inhibitor rapamycin for 72 h. Rapamycin (50 nM) was added 30 min prior to the AST treatment. Representative immunoblots from at least three independent experiments are shown. β-actin was used as internal control in immunoblot assay. Arbitrary data are expressed as mean ± S.E.M., with statistical significance * p < 0.05, ** p < 0.01 when compared with the untreated group at 0 h (A) or control group (B); + p < 0.05 when compared with rapamycin group.