Escin induces apoptosis in human bladder cancer cells: An in vitro and in vivo study

Escin (beta-escin) is used as traditional folk medicine. The anti-tumour effects of escin have been demonstrated in vitro in certain cell lines, but its effect on bladder cancer has not been well investigated. In this study, the apoptotic activity of escin dissolved in dimethyl sulfoxide (DMSO) in bladder cancer cells and normal peripheral blood mononuclear cells (PBMC) and SV-HUC1 cells (controls) was determined. Cell cytotoxicity was assessed using the MTT assay. Cell cycle, Reactive oxygen species (ROS) generation, annexin V-FITC staining (for detecting early apoptosis), and changes in mitochondrial membrane potential were evaluated using flow cytometry. Expression of apoptosis-related proteins such as Fas (CD95) death receptor/FADD (Fas-associated protein with death domain) and BCL2 family of proteins was assessed using immunoblotting. Escin dose-dependently inhibited the growth of human bladder cancer cells, and showed IC50 of similar to 40 mu M. The cell population in the sub-G1 phase, annexin-V staining, Fas expression, ratio of BAX/BCL2, cleavage of activated caspase-3/-8/-9, increase in poly (ADP-ribose) polymerase (PARP) levels, and suppression of nuclear factor kappa B (NF-kappa B) were observed after 24 h of escin treatment. Escin decreased mitochondrial membrane potential and increased cytochrome C release via generation of reactive oxygen species, which led to apoptosis of bladder cancer cells. Furthermore, escin effectively inhibited bladder tumour growth in a xenograft mouse model. Together, these results demonstrate that escin induces apoptosis in human bladder cancer cells through the Fas death receptor and mitochondrial pathways and inhibits bladder tumour growth. Escin is a potential chemotherapeutic agent for bladder cancer.