AST suppresses HIF-1α and VEGF induction under hypoxia in colon cancer cells. CoCl2 (100 μM) was added to the culture medium of HCT 116 cells 30 min prior to various drug treatments to mimic hypoxic condition. (A) The induction of HIF-1α and its downstream molecule VEGF by CoCl2 over a 24-hour course was monitored in HCT 116 cells. The effect of AST (80 μg/ml) on HIF-1α and VEGF protein and mRNA expression was then assessed. (B) Combined treatment of AST and rapamycin (50 nM) suppressed HIF-1α and VEGF protein expression under CoCl2-mimicked hypoxic condition in HCT 116 cells. Data represents the mean of at least three independent experiments. β-actin and GAPDH were used as internal control in immunoblot assay and RT-PCR, respectively. Arbitrary data are expressed as mean ± S.E.M., with statistical significance * p < 0.05 when compared with control group; # p < 0.05, ## p < 0.01 when compared with CoCl2 hypoxia group; + p < 0.05 when compared with CoCl2 + rapamycin group.