MAPK8 and urinary bladder cancer: In this study, we demonstrated that flaccidoxide-13-acetate induces apoptosis in RT4 and T24 bladder cancer cells, and the process is mediated by induction of mitochondrial dysfunction and activation of ER stress, which also involves initiation of the p38 and JNK pathways and inhibition of the PI3K/AKT pathway (Figure 6).