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Research article2010Peer reviewedOpen access

Phosphorylation by Cdk2 is required for Myc to repress Ras-induced senescence in cotransformation

Hydbring, Per; Bahram, Fuad; Su, Yingtao; Tronnersjö, Susanna; Högstrand, Karl; Von Der Lehr, Natalie; Sharifi, Hamid Reza; Lilischkis, Richard; Hein, Nadine; Wu, Siqin; Vervoorts, Jorg; Henriksson, Marie; Grandien, Alf; Luscher, Bernhard; Larsson, Lars-Gunnar

Abstract

The MYC and RAS oncogenes are frequently activated in cancer and, together, are sufficient to transform rodent cells. The basis for this cooperativity remains unclear. We found that although Ras interfered with Myc-induced apoptosis, Myc repressed Ras-induced senescence, together abrogating two main barriers of tumorigenesis. Inhibition of cellular senescence required phosphorylation of Myc at Ser-62 by cyclin E/cyclin-dependent kinase (Cdk) 2. Cdk2 interacted with Myc at promoters, where it affected Myc-dependent regulation of genes, including Bmi-1, p16, p21, and hTERT, which encode proteins known to control senescence. Repression of senescence by Myc was abrogated by the Cdk inhibitor p27Kip1, which is induced by antiproliferative signals like IFN-gamma or by pharmacological inhibitors of Cdk2 but not by inhibitors of other Cdks. In contrast, a phospho-mimicking Myc-S62D mutant was resistant to these manipulations. Inhibition of cyclin E/Cdk2 reversed the senescence-associated gene expression pattern imposed by Myc/cyclin E/Cdk2. This indicates a role of Cdk2 as a transcriptional cofactor and activator of the antisenescence function of Myc and provides mechanistic insight into the Myc-p27Kip1 antagonism. Finally, our findings highlight that pharmacological inhibition of Cdk2 activity is a potential therapeutical principle for cancer therapy, in particular for tumors with activated Myc or Ras.

Keywords

oncogenes; transcription; cell cycle; p27Kip1; cyclin E

Published in

Proceedings of the National Academy of Sciences
2010, Volume: 107, number: 1, pages: 58-63
Publisher: NATL ACAD SCIENCES

      SLU Authors

            • Sustainable Development Goals

              Ensure healthy lives and promote well-being for all at all ages

              UKÄ Subject classification

              Animal and Dairy Science
              Veterinary Science

              Publication identifier

              DOI: https://doi.org/10.1073/pnas.0900121106

              Permanent link to this page (URI)

              https://res.slu.se/id/publ/61011