Toona sinensis (aqueous leaf extracts) induces apoptosis through the generation of ROS and activation of intrinsic apoptotic pathways in human renal carcinoma cells

Toona sinensis has been shown to have anti-proliferative effects on several human cancer cell lines. In the present study, we used two clear cell types of renal cell carcinoma (ccRCC) cell lines to study the anti-tumour effect of the T. sinensis leaf extract (TSL-1). TSL-1 was shown to be cytotoxic to ccRCC cells in a concentration- and time-dependent manner. We found that treatment with TSL-1 induced apoptotic characteristics, reactive oxygen species accumulation, and mitochondrial membrane potential reduction in ccRCC cells. Furthermore, treatment with TSL-1 increased the expression of activated caspase-3, -7, -9, and cleaved PARP. TSL-1 also caused cytochrome c release from mitochondria and down-regulation of Bcl-2 and heat shock proteins. We suggest that the TSL-1-induced cytotoxic effects may be due to quercetin, gallic acid, and tannic acid. Taken together, the present study suggests that TSL-1 induces apoptosis in ccRCC cell lines by activating mitochondrial-dependent caspases and inhibiting anti-apoptotic proteins.