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Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors
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CR8, a potent and selective, roscovitine-derived inhibitor of cyclin-dependent kinases

K Bettayeb1, N Oumata, A Echalier

  • 1CNRS, Cell Cycle Group, Station Biologique, Bretagne, France.

Oncogene
|June 25, 2008
PubMed

Insights

A new drug, CR8, is a more potent analog of roscovitine, effectively inhibiting cyclin-dependent kinases (CDKs) and inducing cancer cell death. This discovery offers improved antitumor potential for cancer treatment strategies.

Area of Science:

  • Medicinal Chemistry
  • Molecular Biology
  • Cancer Research

Background:

  • Cyclin-dependent kinases (CDKs) are crucial regulators of the cell cycle, and their dysregulation is implicated in various cancers.
  • Roscovitine (Seliciclib) is a purine-based CDK inhibitor in clinical trials for non-small-cell lung and nasopharyngeal cancers.
  • There is a need for more potent and selective CDK inhibitors to enhance anti-cancer therapeutic efficacy.

Purpose of the Study:

  • To design and synthesize novel, more potent analogues of roscovitine.
  • To evaluate the selectivity and potency of the new analogues against a panel of kinases.
  • To assess the cellular effects and anti-cancer potential of the lead compound in preclinical models.

Main Methods:

  • Extensive medicinal chemistry efforts focused on optimizing the N6 position of roscovitine.
  • In vitro kinase inhibition assays were performed against 108 kinases to determine selectivity.
  • Cocrystallography was used to elucidate the binding mode of inhibitors with CDK2/cyclin A.
  • Cellular assays were conducted in human neuroblastoma SH-SY5Y cells and 25 other cell lines to assess effects on CDK substrate phosphorylation and apoptosis.

Main Results:

  • Compound CR8, an optimized N6-substituted roscovitine analogue, was identified.
  • CR8 demonstrated exquisite selectivity for CDK1/2/3/5/7/9, showing 2- to 4-fold greater potency than (R)-roscovitine.
  • Cocrystal structures revealed that CR8 and (R)-roscovitine bind to CDK2/cyclin A in virtually identical poses.
  • In cellular studies, CR8 was 25-50 times more potent than (R)-roscovitine in inhibiting CDK1 and CDK9 substrate phosphorylation.
  • CR8 exhibited significantly enhanced potency in inducing various apoptotic cell death parameters (40-68 fold) across 25 cell lines.

Conclusions:

  • Second-generation analogues of (R)-roscovitine, such as CR8, can be designed with significantly improved potency and selectivity.
  • CR8 displays enhanced antitumor potential compared to (R)-roscovitine due to its superior ability to inhibit CDK activity and induce cancer cell apoptosis.
  • These findings support the further development of CR8 as a potential anti-cancer therapeutic agent.

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