The effects of the compounds on cell viability. The anti-proliferation of HeLa and HEK293 cells were examined using WST-1® solution after treatment with each compound and EGF. The HEK293 (A) and HeLa (B) cells were treated with the indicated concentrations (0, 1, 5, 10, 25, 50, 100 and 200 μg/mL) of each compound for 40 min, and then exposed to EGF (10 ng/mL for 10 min). Values are expressed relative to that of vehicle-treated cells (DMSO), normalized to 100%. Values shown in the graphs are mean ± SEM and were obtained from three independent experiments.