Anticancer effects of clinacanthus nutans crude extracts in cervical cancer cells

Abstract

Cervical cancer has one of the highest death recorded percentages among women in the world especially in less developed countries. Moreover, the presence of cancer stem cells in cervical cancer tumours is believed to cause resistance to conventional therapies. Previous studies have shown that C. nutans extracts possess antioxidant and anti-proliferative effects towards several cervical cancer cell lines including HeLa cells. This study is focused at examining the anticancer effects of ethanolic C. nutans leave extract on cervical cancer cell viability, proliferation and its ability to induce apoptosis in cervical cancer cells. In order to achieve these objectives, the MTS, CyQuant and active caspase 3/7 assays as well as immunofluorescence microscopy analysis were conducted respectively on Hela cells which represent an invasive form of cervical cancer. Treatment of C. nutans leave extract at concentrations of 0-50 μg/mL showed a significant reduction in cell viability and proliferation in a dose dependent manner on the Hela cells. An IC50 of 40 μg/mL and 20 μg/mL C. nutans were observed respectively in inducing reduction in cell viability and proliferation. Furthermore, Hela cells treated with C. nutans resulted in a reduced expression level of CD133 cervical cancer stem cell maker compared to the untreated cells. A further reduction in cell proliferation compared to cell viability in Hela cells and reduced CD133 expression may suggest that C. nutans may specifically target cervical cancer stem cells. Additionally, an increased caspase-3/7 activity in Hela cells treated with C. nutans indicated that the plant extract induced apoptosis. Apoptosis was also demonstrated through change in Hela cell morphology and formation of apoptotic bodies upon C. nutans. Findings of this study suggest that C. nutans is a potential anticancer agent which can be used in adjuvant chemotherapy treatment of cervical cancer.