Cyclin-dependent kinase 1 expression is inhibited by p16(INK4a) at the post-transcriptional level through the microRNA pathway

Oncogene. 2011 Apr 21;30(16):1880-91. doi: 10.1038/onc.2010.570. Epub 2010 Dec 20.


The p16(INK4a) protein regulates cell cycle progression mainly by inhibiting the activity of G1-phase cyclin-dependent kinases (CDKs) 4 and 6, the subsequent retinoblastoma protein (pRb) phosphorylation and E2F transcription factor release. The p16(INK4a) protein can also repress the activity of other transcription factors, such as c-myc, nuclear factor-kappaB and c-Jun/AP1. Here, we report that, in two p16(-/-), pRb(WT) and p53(WT) cell lines (MCF7 and U87), p16(INK4a) overexpression induces a dramatic decrease in CDK1 protein expression. In response to p16(INK4a), the decreased rate of CDK1 protein synthesis, its unchanged protein half-life, unreduced CDK1 mRNA steady-state levels and mRNA half-life allow us to hypothesize that p16(INK4a) could regulate CDK1 expression at the post-transcriptional level. This CDK1 downregulation is mediated by the 3'-untranslated region (3'UTR) of CDK1 mRNA as shown by translational inhibition in luciferase assays and is associated with a modified expression balance of microRNAs (miRNAs) that potentially regulate CDK1, analyzed by TaqMan Human microRNA Array. The p16(INK4a)-induced expression of two miRNAs (miR-410 and miR-650 chosen as an example) in MCF7 cells is confirmed by individual reverse transcription-qPCR. Furthermore, we show the interaction of miR-410 or miR-650 with CDK1-3'UTR by luciferase assays. Endogenous CDK1 expression decreases upon both miRNA overexpression and increases with their simultaneous inhibition. The induction of miR-410, but not miR-650 could be related to the pRb/E2F pathway. These results demonstrate the post-transcriptional inhibition of CDK1 by p16(INK4a). We suggest that p16(INK4a) may regulate gene expression by modifying the functional equilibrium of transcription factors and consequently the expression balance of miRNAs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • CDC2 Protein Kinase / antagonists & inhibitors*
  • CDC2 Protein Kinase / metabolism
  • Cell Line, Tumor
  • Cyclin-Dependent Kinase Inhibitor p16 / physiology*
  • Humans
  • MicroRNAs / metabolism*
  • RNA Processing, Post-Transcriptional*


  • Cyclin-Dependent Kinase Inhibitor p16
  • MicroRNAs
  • CDC2 Protein Kinase