Lupeol induces S-phase arrest and mitochondria-mediated apoptosis in cervical cancer cells

Abstract

Cervical cancer is fourth most common fatal cancer in women worldwide. Lupeol is a dietary triterpenoid and has shown its anticancer efficacy against various cancer types with selectivity in targeting cancer cells. In the present study, anticancer efficacy and mechanism of action of a phytochemical, lupeol, in human cervical carcinoma (HeLa) cells has been examined. The anticancer efficacy of lupeol was assessed by trypan blue cell counting, annexin Vassay, cell cycle analysis, expression of apoptotic proteins by RT-PCR and Western blotting and assessment of mitochondrial ROS generation by mitosox and mitotracker assays. Our results demonstrated that lupeol decreased cell proliferation and viability of HeLa cells significantly (p less than 0.001). Lupeol induced S-phase cell cycle arrest and also decreased the expression of S-phase Cyclins and CDKs and increased the expression of cyclin-dependent kinase inhibitors, p21 at transcriptional and translational level. Further, lupeol induced apoptosis and increased the expression of apoptosis markers such as cleaved PARP and Bax:Bcl-2 ratio. Furthermore, mitosox and mitotracker dye incubation followed by FACS analysis showed an increase in mitochondrial superoxide generation and reduction in healthy mitochondrial mass. These results suggest that lupeol could be an effective chemotherapeutic agent against cervical carcinoma due to its growth inhibitory activity through induction of S-phase cell cycle arrest and apoptosis.