USP14 and prostate cancer: To determine the basic role of USP14 in prostate cancer, we used the CellTiter 96 Aqueous One Solution reagent (MTS) assay to test the effect of various concentrations of IU1 (6.25, 12.5, 25, 50, 100 μM), a selective and potent inhibitor of USP14, on the cell growth of LNcap cells.