CDK7 inhibition induces apoptosis in acute myeloid leukemia cells and exerts synergistic antileukemic effects with azacitidine in vitro and in vivo

THZ1, a CDK7 inhibitor, has potent antitumor effects in several cancers; however, its role in Acute myeloid leukemia (AML) is unclear. We explored the effects and potential mechanisms of THZ1, alone and in combination with azacitidine (AZA), in AML cells and xenograft models. THZ1 decreased cell viability, induced apoptosis in a dose and time-dependent manner, induced G0/G1 cell cycle arrest, decreased phosphorylated CDK1 and CDK2 expression, and inhibited RNA Pol II phosphorylation at multiple serine sites. The combination of AZA and THZ1 exhibited synergistic antileukemic effects in AML cell lines and primary cells with MCL1 and c-MYC downregulation. Moreover, the combination therapy significantly decreased tumor burden and prolonged animal survival in xenograft mice models. Our data demonstrate that CDK7 inhibition induces the apoptosis of AML cells and exerts a synergistic antileukemia effect with AZA in vitro and in vivo, which supports future exploration of this combination in clinical studies.