Investigating the role of Thymoquinone in increasing the rate of Cisplatin-induced apoptosis through oxidative DNA damage in Saso-2 cancer cells

Abstract

Osteosarcoma is a rare disease with a poor prognosis. Fundamental research has enabled a better understanding of osteosarcoma's pathogenesis and the discovery of potential new treatments. Finding therapeutic and prophylactic approaches that can target tumor cells without affecting normal cells and overcoming drug resistance would be miraculously useful. Here, we present new evidence that combination therapy of thymoquinone with cisplatin exacerbates cisplatin's apoptotic effects by inducing oxidative DNA damage in Saos-2 cells. Methods: The cells will be cultured in RPMI-1640 medium containing 10% FBS. It is then treated alone / with a combination of thymoquinone and cisplatin. Their cytotoxic effect on the cells is investigated within 72 hours. Their ideal concentration is determined alone and in combination with each other using MTT assay. Western blot will be performed to evaluate the expression of γ-H2AX protein. The amount of 8-OXO-dG is then measured as a marker of DNA damage by ELISA in groups treated with thymoquinone, cisplatin, and a combination of both. Flow cytometry will be performed to check for cell apoptosis. Results: Thymoquinone significantly increases the cytotoxic effects of cisplatin. Besides, combination therapy of thymoquinone with cisplatin significantly increased γ-H2AX expression levels in the Saos-2 cell line. Also, this combination therapy leads to a dramatic increase in ROS levels and 8-OXO-dG expression levels. Also, thymoquinone exacerbated cisplatin-induced apoptosis in Saos-2 cells compared to cells treated with thymoquinone or cisplatin alone.