The study was initiated in bladder cancer cell lines UMUC-3 and RT-4 because of our previous report showing DMAPT-mediated cell cycle arrest and apoptosis of UMUC-3 cells in vitro and inhibition of tumor growth in xenograft models.25 DMAPT reduced the levels of HDAC-1 in UMUC-3 cells but had a modest effect in RT-4 cells (Figure 1a). Here, HDAC1 is linked to urinary bladder cancer.