Liu, Xiangrui, Shi, Shenhua, Lam, Frankie, Pepper, Christopher John, Fischer, Peter M. and Wang, Shudong 2012. CDKI-71, a novel CDK9 inhibitor, is preferentially cytotoxic to cancer cells compared to flavopiridol. International Journal of Cancer 130 (5) , pp. 1216-1226. 10.1002/ijc.26127 |
Abstract
Cancer cells appear to depend heavily on antiapoptotic proteins for survival and so targeted inhibition of these proteins has therapeutic potential. One innovative strategy is to inhibit the cyclin-dependent kinases (CDKs) responsible for the regulation of RNA polymerase II (RNAPII). In our study, we investigated the detailed cellular mechanism of a novel small-molecule CDK inhibitor (CDKI-71) in cancer cell lines, primary leukemia cells, normal B - & T- cells, and embryonic lung fibroblasts and compared the cellular and molecular responses to the clinical CDK inhibitor, flavopiridol. Like flavopiridol, CDKI-71 displayed potent cytotoxicity and caspase-dependent apoptosis induction that were closely associated with the inhibition of RNAPII phosphorylation at serine-2. This was caused by effective targeting of cyclinT–CDK9 and resulted in the downstream inhibition of Mcl-1. No correlation between apoptosis and inhibition of cell-cycle CDKs 1 and 2 was observed. CDKI-71 showed a 10-fold increase in potency in tumor cell lines when compared to MRC-5 human fibroblast cells. Significantly, CDKI-71 also demonstrated potent anti-chronic lymphocytic leukemia activity with minimal toxicity in normal B- and T-cells. In contrast, flavopiridol showed little selectivity between cancer and normal cells. Here, we provide the first cell-based evidence that flavopiridol induces DNA double-strand breaks: a fact which may explain why flavopiridol has such a narrow therapeutic window in preclinical and clinical settings. Taken together, our data provide a rationale for the development of selective CDK inhibitors as therapeutic agents and CDKI-71 represents a promising lead in this context.
Item Type: | Article |
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Date Type: | Publication |
Status: | Published |
Schools: | Medicine |
Subjects: | R Medicine > R Medicine (General) R Medicine > RC Internal medicine > RC0254 Neoplasms. Tumors. Oncology (including Cancer) |
Publisher: | John Wiley & Sons |
ISSN: | 0020-7136 |
Last Modified: | 04 Jun 2017 04:35 |
URI: | https://orca.cardiff.ac.uk/id/eprint/41415 |
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