HLCL-61 is a potent and selective PRMT5 inhibitor for treatment of acute myeloid leukemia. HLCL-61 resulted in significantly increased expression of miR-29b and consequent suppression of Sp1 and FLT3 in AML (acute myeloid leukemia) cells. As a result, significant antileukemic activity was achieved. The increased PRMT5 activity enhanced AML growth in vitro and in vivo while PRMT5 downregulation reduced it. In AML cells, PRMT5 interacted with Sp1 in a transcription repressor complex and silenced miR-29b preferentially via dimethylation of histone 4 arginine residue H4R3.

HLCL-61 hydrochloride is a first-in-class small-molecule inhibitor of PRMT5.