Effects of curcumin on bladder cancer cells and development of urothelial tumors in a rat bladder carcinogenesis model

Curcumin, a well-known dietary pigment derived from Curcuma longa, inhibited growth of several types of malignant cells both in vivo and in vitro. Its effects on cell proliferation and the induction of apoptosis in human bladder cancer cell lines and intravesical activity in a rat bladder tumor model were studied. Exposure of human bladder cancer cells to curcumin resulted in the induction of apoptotic cell death and caused cells to arrest in the G2/M phase. The anti-apoptotic Bcl-2 and Survivin protein was downregulated by the curcumin treatment together with enhancement of the Bax and p53 expression. The inhibitory activities of curcumin were stronger than those of cisplatin and could not be prevented by catalase pretreatment in T24 cells. Clonal assay indicated large-dose and short-term curcumin was lethal to bladder cancer cells. Moreover, the in vivo study revealed curcumin did induce apoptosis in situ, inhibit and slow the development of bladder cancer. These observations suggest that curcumin could prove an effective chemopreventive and chemotherapy agent for bladder cancer.