The anti-proliferative and apoptotic effects of crocin on chemosensitive and chemoresistant cervical cancer cells

Cervical cancer is the fourth cause of cancer-related mortality among females worldwide. Although current therapies reduce disease symptoms, resistance of tumor cells to chemotherapy agents after a while is a serious problem. Therefore, utilization of novel adjuvant agents to increase efficiency of chemotherapy is essential. In the last two decades, botanicals with effective anticancer activities have been studied. Among them, the anticancer properties of crocin have been more attended. In this study, the molecular mechanism of crocin action was investigated in sensitive human cervical cancer cell line (OV2008) in comparison with the resistant one (C13). A 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyltetrazolium bromide (MTT) assay showed that crocin inhibits proliferation of sensitive cells (OV2008) at a time- and dose-dependent manner at 48 and 72 h. Also, this inhibitory effect has been shown on resistant cells (C13) at 72 h. Hoechst staining and flow cytometry assay also confirmed these results and revealed that antiproliferative effect of crocin might be due to the induction of apoptosis. Moreover, the genetic mechanism of crocin-induced apoptosis was accomplished by studying the relative expressions of P53, Bax, Bcl2 and miR-365, an upstream regulator of the last two ones. Real-time PCR analysis indicated that 1.5 and 3 mg/ml crocin led to up-regulation of Bax and P53 and down-regulation of Bcl2 and miR-365 at all time intervals in both two cell lines. However, OV2008 cell line was more sensitive to crocin, and alternation of gene expretion was more obvious in this cell line. In this regard, the present study demonstrated the anti-proliferative and apoptotic activities of crocin against both sensitive and resistant cervical cancer cells that may benefit cervical cancer treatment as an adjuvant agent to decrease chemoresistance and increase the efficiency of therapy.