Synergistic anti-cancer effect of pristimerin and docetaxel on human colorectal HCT-116 cells

Pristimerin is a quinonemethide triterpenoid compound that exerts anticancer activities against different cancer cells, including colorectal cancer. The current study aimed to study the cytotoxic and apoptosis-inducing effects of pristimerin alone or in combination with docetaxel on HCT-116 human colorectal cancer cell line. The cytotoxicity of pristimerin, or docetaxel, or the combination on HCT-116 cells were measured using the MTT method. The combination index (CI) was calculated using the isobologram method of Chou and Talalay. Annexin V/PI double staining was used to assess the apoptosis-inducing effect of these agents. Our results showed that both pristimerin and docetaxel showed potent cytotoxic effects against HCT-116 cells in dose-dependent manners. Moreover, the efficacy of docetaxel combined pristimerin was significantly increased, compared to individual treatment. The CI value was (0.55 to 0.89) that indicated the synergistic interaction between two agents to inhibit cell growth of CRC cells. Furthermore, Annexin V/PI assay showed that both agents induced apoptosis in HCT-116 in cancer cells. While treatment with combination resulted in a significant enhancement in apoptosis rates compared to individual treatment. Collectively, the data indicated that pristimerin potentiated the anticancer activities of docetaxel in colon cancer cells by reducing cell viability and promoting apoptosis.