Anticancer effects of a novel chroman analog in HeLa cells are associated with G2­phase arrest and mitochondrial­mediated apoptosis.

ABSTRACT

In the present study, the anticancer activity of 1­[(3S,4R)­2,2­dimethyl­3­oxo­4­(2­piperidonyl)chroman­6­yl]­3­phenylurea (S32) was investigated by testing its effect in vitro on the growth of HeLa cells. First, we showed that the IC50 value of S32 was ~70 µM by using WST­8 assay, and that it significantly inhibited the proliferation and viability of HeLa cells in a dose­dependent manner after 48 h. Morphological changes in apoptotic cells included cellular shrinkage and nuclear condensation. The results of [3H]­thymidine incorporation and flow cytometric analysis indicated that S32 induced inhibition of DNA replication and G2­phase cell cycle arrest. Moreover, S32 induced the levels of reactive oxygen species (ROS) and decreased the mitochondrial membrane potential (MMP) in a time­dependent manner. Using Annexin V­FITC/propidium iodide (PI) dual staining assay, we found that S32 noticeably increased early apoptosis in HeLa cells in a time­dependent manner. The result of western blot analysis showed that the apoptotic induction was associated with an increase in Bax levels and a decrease in Bcl­2 levels, which led to activation of caspase­8, ­9 and ­3. Taken together, our findings demonstrated that S32 induces mitochondrial­mediated apoptosis in HeLa cells and suggest that S32 has potential as an anticancer drug.