Next-Generation CDK2/9 Inhibitors and Anaphase Catastrophe in Lung Cancer

J Natl Cancer Inst. 2017 Jun 1;109(6):djw297. doi: 10.1093/jnci/djw297.

Abstract

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 μM, induced apoptosis up to 42.6% (SD = 5.5%, P < .001) at 2 μM, and caused G1 or G2/M arrest in lung cancer cells with minimal effects on control cells (growth inhibition at 1 μM: 10.6%, SD = 3.6%, P = .32; apoptosis at 2 μM: 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 IC 50 ). CCT68127 inhibited supernumerary centrosome clustering and caused anaphase catastrophe by 14.1% (SD = 3.6%, P < .009 at 1 μM). 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.

MeSH terms

  • Adenosine / analogs & derivatives*
  • Adenosine / pharmacology
  • Adenosine / therapeutic use
  • Anaphase / drug effects*
  • Animals
  • Apoptosis / drug effects
  • Apoptosis Regulatory Proteins
  • Cell Cycle Checkpoints / drug effects
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Centrosome / drug effects
  • Cyclin-Dependent Kinase 2 / antagonists & inhibitors*
  • Gene Knockdown Techniques
  • Humans
  • Intracellular Signaling Peptides and Proteins / genetics*
  • Intracellular Signaling Peptides and Proteins / metabolism
  • Lung Neoplasms / drug therapy*
  • Lung Neoplasms / genetics
  • Male
  • Mice
  • Phosphoproteins / genetics*
  • Phosphoproteins / metabolism
  • Phosphorylation / drug effects
  • Protein Kinase Inhibitors / pharmacology*
  • Protein Kinase Inhibitors / therapeutic use
  • Proto-Oncogene Proteins p21(ras) / genetics
  • Purines / pharmacology
  • Roscovitine
  • Signal Transduction / drug effects

Substances

  • Apoptosis Regulatory Proteins
  • CCT68127
  • CYC065
  • Intracellular Signaling Peptides and Proteins
  • PEA15 protein, human
  • Pea15 protein, mouse
  • Phosphoproteins
  • Protein Kinase Inhibitors
  • Purines
  • Roscovitine
  • Cyclin-Dependent Kinase 2
  • Hras protein, mouse
  • Proto-Oncogene Proteins p21(ras)
  • Adenosine