AZD4573 is a highly selective CDK9 inhibitor that suppresses Mcl-1 and induces apoptosis in hematological cancer cells

ABSTRACT: Phosphorylation of RNA polymerase II by cyclin-dependent kinase 9 (CDK9) is crucial for transcriptional regulation, and acute inhibition of CDK9 results in the rapid downregulation of genes with short-lived transcripts and labile proteins. Multiple non-selective CDK9 inhibitors have progressed clinically but were limited by a narrow therapeutic window. This work describes a novel, potent, and highly selective CDK9 inhibitor, AZD4573. Using integrated transcriptomic and proteomic analyses, loss-of-function pathway interrogation, and pharmacological comparisons, Mcl-1 depletion was identified as a major mechanism through which AZD4573 induces cell death in tumor cells. AZD4573 suppresses Mcl-1 in a dose- and time-dependent manner that causes caspase-3 cleavage in sensitive cancer cells, most notably in hematological malignancies. This pharmacodynamic response is observed in vivo as well, which leads to regressions in both subcutaneous tumor xenografts and disseminated models at tolerated doses as monotherapy or in combination with venetoclax. Fully understanding the mechanism, exposure, and anti-tumor activity of AZD4573 also informed the development of a robust PK/PD/efficacy model that helped select and predict the starting and efficacious dose range in man. Accordingly, AZD4573 is currently being evaluated in a phase I clinical trial for patients with hematological malignancies (clinicaltrials.gov identifier: NCT03263637).

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Homo Sapiens (human)

TISSUE(S): Epithelial Cell, Cell Culture

DISEASE(S): Breast Cancer

SUBMITTER: Valar Nila Roamio Franklin  

LAB HEAD: Clive D'Santos

PROVIDER: PXD013796 | Pride | 2020-05-26

REPOSITORIES: Pride