A novel Cdk9 inhibitor preferentially targets tumor cells and synergizes with fludarabine

作者:Wal**y Elisabeth; Pratt Guy; Shao Hao; Abbas Abdullah Y; Fischer Peter M; Bradshaw Tracey D; Brennan Paul; Fegan Chris; Wang Shudong; Pepper Chris*
来源:Oncotarget, 2014, 5(2): 375-385.
DOI:10.18632/oncotarget.1568

摘要

Cdk9 is a key elongation factor for RNA transcription and functions by phosphorylating the C-terminal domain of RNA polymerase II. Here we present direct evidence that cdk9 is important for cancer cell survival and describe the characterization of the potent cdk9 inhibitor CDKI-73 in primary human leukemia cells. CDKI-73 induced caspase-dependent apoptosis that was preceded by dephosphorylation of cdk9 and serine 2 of RNA polymerase II. CDKI-73 was more potent than the pan-cdk inhibitor flavopiridol and showed %26gt; 200-fold selectivity against primary leukemia cells when compared with normal CD34+ cells. Furthermore, CDKI-73 was equipotent in poor prognostic sub-groups of leukemia patients and showed cytotoxic synergy with the nucleoside analog fludarabine. The Mechanism of synergy was associated with CDKI-73-mediated transcriptional inhibition of MCL1 and XIAP that was maintained when used in combination with fludarabine. Our data present a strong rationale for the development of cdk9 inhibitors such as CDKI-73 as anticancer therapeutics.

  • 出版日期2014-1