The chemosensitization effect of quercetin on cisplatin induces the apoptosis of human colon cancer HT-29 cell line

Objectives: The present study is to investigate the effect of quercetin on cisplatin-induced growth inhibition, apoptosis and nuclear factor-kappa B (NF-κB) expression in colon cancer HT-29 cells. Methods: HT-29 cells were treated with quercetin, cisplatin or the combination of both. MTT assay was applied to examine cell viability. Transmission electron microscopy and laser scanning confocal microscopy were used to observe morphological changes of HT-29 cells. Flow cytometry was employed to determine the apoptosis rate of different groups. Immunohistochemical analysis was introduced to measure the expression level of NF-κB. Results: MTT assay showed that the combination of both drugs had the strongest inhibitory effect on cell growth. Cells in the combination group showed typical apoptotic morphological changes under the microscope. Flow cytometry showed that the apoptosis rate in the combination group was the highest, and the cell cycle was blocked in G2/M phase. Immunohistochemistry showed that NF-κB expression in the combination group was significantly lower than that in cisplatin group. Conclusions: Quercetin enhances cisplatin-induced apoptosis of human colon cancer HT-29 cells. The possible mechanism is partially the inhibition of the activation of NF-κB expression, suggesting that quercetin in combination with cisplatin provides a possibly effective approach in the treatment of patients with colon cancer.