CMP-5 hydrochloride is a potent and selective PRMT5 inhibitor, while displays no activity against PRMT1/4/7 enzymes. It selectively blocks S2Me-H4R3 by inhibiting PRMT5 methyltransferase activity on histone preparations.

MTH1 (cells):3.7 μM , hTh2 cells:36.1 μM , MTH2 (cells):9.2 μM , hTh1 cells:26.9 μM

CMP-5 (0-100 μM; 24-72 hours) is selectively toxic to lymphoma cells but shows limited toxicity to normal resting B lymphocytes even after prolonged incubation. CMP-5 (0-40 μM; 24 hours) preferentially suppresses the proliferation of human Th1 cells over Th2 cells (43 versus 9% inhibition, respectively). The sensitivity of Th1 cells over Th2 cells to PRMT5 inhibition is different, the IC50 values are 26.9 μM and 31.6 μM in human Th1 cells and Th2 cells, respectively. CMP-5 (40 μM; 24 hours) decreases p-BTK and pY(416)SRC expression in 60A cells when it compares to the DMSO-treated group. CMP-5 (25 μM; 24 hours) alone inhibits mouse Th1 cell proliferation by 91%, when added different doses IL-2, IL-2 enhances proliferation and reaches a peak at 5 ng/ml [1].