A novel synergistic anticancer effect of fungal cholestanol glucoside and paclitaxel: Apoptosis induced by an intrinsic pathway through ROS generation in cervical cancer cell line (HeLa)

Abstract

In the search for efficient therapeutics with economically viable for cancer treatment, combination therapy has developed as a keystone in the pursuit of novel approaches for drug discovery. In this regard, we confirmed the presence of cholestanol glucoside (CG) in Lasiodiplodia theobromae culture filtrate and its production was estimated to be 20.01 mg/l. The purified fungal CG was obtained with a molecular mass of 550.18 m/z. The combination of CG and paclitaxel (PTX) was found to have potent cytotoxicity against HeLa cells. We revealed that the synergistic effect of CG and PTX induced apoptosis through the formation of nuclear fragments, DNA fragmentation and sub G1 cell cycle arrest. Further, it was proven that apoptosis took place by loss of the mitochondrial membrane potential (MMP) through reactive oxygen species (ROS) production and caspase 3/7 activity. Moreover, the data suggests that the synergistic effect of CG and PTX played a role in a mitochondrial intrinsic pathway through the apoptotic gene expression of Bax, caspase-9 and caspase-3. In addition, the down-regulation of Bcl-2 strongly described the induced apoptosis through an intrinsic pathway using the Western blot analysis. The conclusion of this study is that a combination of CG and PTX has synergistic apoptotic effects in HeLa cells, which provides a possible therapeutic strategy for cancer therapy in the future.

Keywords: Apoptosis; Cholestanol glucoside; Combination therapy; Cytotoxicity; HeLa; Paclitaxel.