Investigation of the Inhibitory Effect of Platycodin D in Human Transitional Cell Carcinoma Cell Line 5637

Platycodin D is an active component isolated from Chinese herb Platycodonis radix with various pharmacological activities, such as antitussive, expectorant, anti-inflammatory, and analgesic effects. Interestingly, platycodin D also exerts anticancer effects against several types of cancer. However, few studies on the anti-tumour effects of platycodin against urinary bladder cancer have been reported. In this study, we explored the anti-tumour effect of platycodin D against human bladder cancer and its mechanisms in vitro and in vivo. We found that platycodin D had significant anti-proliferative effects on four types of cancer cells, especially the 5637 bladder cancer cell line, and exerted these effects by preventing cell cycle progression from G0/G1 to S phase, down-regulating Ki-67 and cyclin D1 protein expression and up-regulating P21 protein expression. Furthermore, platycodin D inhibited 5637 cell migration by decreasing twist-related protein 1 (Twist1) and matrix metallopeptidase 2 (MMP2) expression and exerted significant tumour-suppressive effects in tumour-bearing nude mice. Platycodin D also increased caspase-9, caspase-8, caspase-3, and p53 expression and decreased Bcl-2 expression in tumour tissues. Taken together, our results provide a theoretical basis for application of platycodin D in treating urinary bladder cancer.