Icariin inhibits the growth of human cervical cancer cells by inducing apoptosis and autophagy by targeting mTOR/PI3K/AKT signalling pathway

Purpose: Cervical cancer causes significant morbidity and mortality among women worldwide. The currently available treatment options are not efficacious and also create severe adverse effects. It is apparent that new therapeutic approaches are needed for this cancer. In this study, we examined the anticancer effects of a natural flavonoid, Icariin, against human cervical cancer cells. Methods: The anti-proliferative effects of Icariin were evaluated on cervical cancer HeLa cell line and normal HCvEpC cells by cell counting assay. The effect of Icariin on colony formation was assessed by colony formation assay. Apoptotic effects were determined by acridine orange/ethidium bromide (AO/EB) and DAPI staining. Autophagy was investigated by electron microscopy. Reactive oxygen species (ROS) and mitochondrial membrane potential (MMP) levels were estimated by flow cytometry. Protein expression was evaluated by western blotting. Results: Icariin inhibited the growth of HeLa cervical cancer cells dose-dependently. IC50 of Icariin was 20 mu M against the HeLa cells with comparatively negligible toxic effects on normal HCvEpC cells. The anticancer effects of Icariin were due to induction of apoptosis which was accompanied with cleavage of caspase 3 and 9, upregulation of Bax and downregulation of Bcl-2. Icariin also prompted autophagy in HeLa cells and enhanced the LC3 II expression concentration-dependently. Icariin also induced the generation of ROS and diminished the MMP levels in HeLa cells and blocked the mTOR/PI3K/AKT signalling cascade, suggestive of its potent anticancer activity. Conclusions: Taken together Icariin may prove potent and efficacious lead molecule for the development of therapy for cervical cancer.