SIRT4 and urinary bladder cancer: These results suggest that UNC5B and SIRT4 are required at least in part for CDDP-induced apoptotic cell death of bladder cancer cells, and that miR-424 confers CDDP resistance on bladder cancer cells through down-regulation of UNC5B and SIRT4. In support of this notion, miR-424 mimics-mediated decrease in CDDP sensitivity of T24 and 5637 cells was partially restored by forced expression of UNC5B or SIRT4 lacking miR-424-responsive 3′-UTR (Fig. 4d).