Combinational Synergistic Role of Thymoquinone and Celastrol in Colon Carcinoma Cell Line

Colon carcinoma (HCT-116) cells are highly aggressive cell line and cell proliferation of colon carcinoma cells are rapid and uncontrolled. Treatment of colorectal cancer cells can be achieved through the use of chemotherapeutic agents. However, the treatment with a single type of chemical may require high dosages, which leads to toxicity. To resolve this issue, synergistic combinational treatment of Thymoquinone (TQ) and Celastrol (CLS) can be promising strategy to reduce proliferation and cell viability of the colorectal cancer cells. Evaluation of cell viability and cell growth were determined fort he combinational and alone treatments of TQ and CLS using MTT assay. Combinational concentrations and the combination indexes of these two agents were determined by the CompuSYN software program. Half maximal inhibitory concentrations (IC50) of TQ and CLS were determined as 102 µM and 7 µM, respectively. Four different combinations of these two chemical agents were tested and the results revealed strong synergistic effect against HCT-116 colon cancer cells. Reactive oxygen species production was also evaluated by monitoring the production of highly fluorescent DCF from DCFH-DA. Compared to the alone treatments of the both drugs, overproduction of ROS in combinational treatments supported the results obtained from cell viability. Our findings demonstrated that combinational strategy of TQ and CLS has strong synergistic activity against the HCT-116 cancer cells and it can be a promising strategy to increase the effect of the drugs.