Background: The first generation CDK2/7/9 inhibitor seliciclib (CYC202) causes multipolar anaphase and apoptosis in lung cancer cells with supernumerary centrosomes (known as anaphase catastrophe). We investigated a new and potent CDK2/9 inhibitor, CCT68127 (Cyclacel). Methods: CCT68127 was studied in lung cancer cells (three murine and five human) and control murine pulmonary epithelial and human immortalized bronchial epithelial cells. Robotic CCT68127 cell-based proliferation screens were used. Cells undergoing multipolar anaphase and inhibited centrosome clustering were scored. Reverse phase protein arrays (RPPAs) assessed CCT68127 effects on signaling pathways. The function of PEA15, a growth regulator highlighted by RPPAs, was analyzed. Syngeneic murine lung cancer xenografts (n = 4/group) determined CCT68127 effects on tumorigenicity and circulating tumor cell levels. All statistical tests were two-sided. Results: CCT68127 inhibited growth up to 88.5% (SD = 6.4%, P < .003) at 1 lM, induced apoptosis up to 42.6% (SD = 5.5%, P < .001) at 2 lM, and caused G1 or G2/M arrest in lung cancer cells with minimal effects on control cells (growth inhibition at 1 lM: 10.6%, SD = 3.6%, P = .32; apoptosis at 2 lM: 8.2%, SD = 1.0%, P = .22). A robotic screen found that lung cancer cells with KRAS mutation were particularly sensitive to CCT68127 (P = .02 for IC50). CCT68127 inhibited supernumerary centrosome clustering and caused anaphase catastrophe by 14.1% (SD = 3.6%, P < .009 at 1 lM). CCT68127 reduced PEA15 phosphorylation by 70% (SD = 3.0%, P = .003). The gain of PEA15 expression antagonized and its loss enhanced CCT68127-mediated growth inhibition. CCT68127 reduced lung cancer growth in vivo (P < .001) and circulating tumor cells (P = .004). Findings were confirmed with another CDK2/9 inhibitor, CYC065. Conclusions: Next-generation CDK2/9 inhibition elicits marked antineoplastic effects in lung cancer via anaphase catastrophe and reduced PEA15 phosphorylation.
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© The Author 2017. Published by Oxford University Press. All rights reserved.
All Science Journal Classification (ASJC) codes
- Cancer Research