Abstract 700: Gene expression profiling of cyclin-dependent kinase (CDK) inhibition in cancer cells.

Proceedings: AACR 104th Annual Meeting 2013; Apr 6-10, 2013; Washington, DC Cyclin-dependent kinases (CDKs) form complexes with partner cyclins to regulate cell cycle progression and transcription. CDK1, CDK2, CDK4 and CDK6 all regulate cell cycle progression and CDK8 and CDK9 are regulators of transcription. CDK7 is a unique member of this family because it can regulate the cell cycle CDKs as part of the CDK-activating kinase (CAK) and also transcription in conjunction with the TFIIH transcription factor by phosphorylating the COOH-terminal domain of RNA polymerase II (Pol II CTD). A hallmark of cancer is deregulated cell cycle progression and many cancers have abnormal CDK activity which makes CDKs a good target for cancer therapy. Here we show BS-194, a selective and potent CDK inhibitor, which inhibits CDK2, CDK1, CDK5, CDK7 and CDK9 (IC50 = 3, 30, 30, 250 and 90nmol/L, respectively). In vitro cell based assays have shown that BS-194 inhibits the phosphorylation of CDK substrates, Rb and RNA Poll II, down regulation of cyclins A, E and D1 and cell cycle arrest in the S and G2/M phases. BS-194 also has potent anti-proliferative activity in 60 cancer cell lines tested (mean GI50 = 28nmol/L). BS-194 is orally bioavailable and shows potent in vivo tumour growth inhibition of xenograft models of MCF7 and HCT116 cells. We have used BS-194 as a potent inhibitor of CDK activity in HCT116 cells and performed gene microarray analysis to determine novel pathways and identify novel biomarkers associated with CDK inhibition. In summary, the gene microarray has identified genes differentially expressed in response to BS-194 treatment that are primarily involved in cell cycle, apoptosis and transcription pathways. Citation Format: Silvia Ottaviani, Sean Delaney, Hetal Patel, Manikandan Periyasamy, Alexander Bondke, Brian Slafer, Richard Starkey, Sebastian H.B. Kroll, Matthew J. Fuchter, Anthony G.M. Barrett, R. Charles Coombes, Simak Ali. Gene expression profiling of cyclin-dependent kinase (CDK) inhibition in cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 700. doi:10.1158/1538-7445.AM2013-700