R-Roscovitine simultaneously targets both the p53 and NF-kappaB pathways and causes potentiation of apoptosis: implications in cancer therapy

Cell Death Differ. 2008 Feb;15(2):263-73. doi: 10.1038/sj.cdd.4402257. Epub 2007 Nov 2.

Abstract

Seliciclib (CYC202, R-Roscovitine) is a 2, 6, 9-substituted purine analog that is currently in phase II clinical trials as an anticancer agent. We show in this study that R-Roscovitine can downregulate nuclear factor-kappa B (NF-kappaB) activation in response to tumor necrosis factor (TNF)alpha and interleukin 1. Activation of p53-dependent transcription is not compromised when R-Roscovitine is combined with TNFalpha. We characterize the molecular mechanism governing NF-kappaB repression and show that R-Roscovitine inhibits the IkappaB kinase (IKK) kinase activity, which leads to defective IkappaBalpha phosphorylation, degradation and hence nuclear function of NF-kappaB. We further show that the downregulation of the NF-kappaB pathway is also at the level of p65 modification and that the phosphorylation of p65 at Ser 536 is repressed by R-Roscovitine. Consistent with repression of canonical IKK signaling pathway, the induction of NF-kappaB target genes monocyte chemoattractant protein, intercellular adhesion molecule-1, cyclooxygenase-2 and IL-8 is also inhibited by R-Roscovitine. We further show that treatment of cells with TNFalpha and R-Roscovitine causes potentiation of cell death. Based on these results, we suggest the potential use of R-Roscovitine as a bitargeted anticancer drug that functions by simultaneously causing p53 activation and NF-kappaB suppression. This study also provides mechanistic insight into the molecular mechanism of action of R-Roscovitine, thereby possibly explaining its anti-inflammatory properties.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Apoptosis / drug effects*
  • Cell Line, Tumor
  • Dose-Response Relationship, Drug
  • Humans
  • I-kappa B Kinase / antagonists & inhibitors
  • I-kappa B Kinase / metabolism
  • I-kappa B Proteins / metabolism
  • Interleukin-1 / metabolism
  • NF-KappaB Inhibitor alpha
  • NF-kappa B / antagonists & inhibitors
  • NF-kappa B / metabolism*
  • Phosphorylation / drug effects
  • Purines / pharmacology*
  • Roscovitine
  • Transcription Factor RelA / antagonists & inhibitors
  • Transcription Factor RelA / metabolism
  • Tumor Necrosis Factor-alpha / antagonists & inhibitors
  • Tumor Necrosis Factor-alpha / metabolism*
  • Tumor Suppressor Protein p53 / metabolism*

Substances

  • I-kappa B Proteins
  • Interleukin-1
  • NF-kappa B
  • NFKBIA protein, human
  • Purines
  • Transcription Factor RelA
  • Tumor Necrosis Factor-alpha
  • Tumor Suppressor Protein p53
  • Roscovitine
  • NF-KappaB Inhibitor alpha
  • I-kappa B Kinase