The mysterious human epidermal cell cycle, or an oncogene-induced differentiation checkpoint

Cell Cycle. 2012 Dec 15;11(24):4507-16. doi: 10.4161/cc.22529. Epub 2012 Oct 31.

Abstract

Fifteen years ago, we reported that proto-oncogene MYC promoted differentiation of human epidermal stem cells, a finding that was surprising to the MYC and the skin research communities. MYC was one of the first human oncogenes identified, and it had been strongly associated with proliferation. However, it was later shown that MYC could induce apoptosis under low survival conditions. Currently, the notion that MYC promotes epidermal differentiation is widely accepted, but the cell cycle mechanisms that elicit this function remain unresolved. We have recently reported that keratinocytes respond to cell cycle deregulation and DNA damage by triggering terminal differentiation. This mechanism might constitute a homeostatic protection face to cell cycle insults. Here, I discuss recent and not-so-recent evidence suggesting the existence of a largely unexplored oncogene-induced differentiation response (OID) analogous to oncogene-induced apoptosis (OIA) or senescence (OIS). In addition, I propose a model for the role of the cell cycle in skin homeostasis maintenance and for the dual role of MYC in differentiation.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Apoptosis / genetics
  • Apoptosis / physiology
  • Cell Cycle / genetics
  • Cell Cycle / physiology*
  • Cell Differentiation / genetics
  • Cell Differentiation / physiology
  • Cellular Senescence / genetics
  • Cellular Senescence / physiology
  • Epidermal Cells*
  • Humans
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-myc / genetics
  • Proto-Oncogene Proteins c-myc / metabolism

Substances

  • MAS1 protein, human
  • Proto-Oncogene Mas
  • Proto-Oncogene Proteins c-myc