HIF-1α controls keratinocyte proliferation by up-regulating p21(WAF1/Cip1)

Young Suk Cho, Jae Moon Bae, Yang Sook Chun, Jin Ho Chung, Yoon Kyung Jeon, In San Kim, Myung Suk Kim, Jong Wan Park

Research output: Contribution to journalArticlepeer-review

38 Citations (Scopus)


The cyclin-dependent kinase inhibitor p21WAF1/Cip1 plays a central role in a spatial and temporal balance of epidermal keratinocyte proliferation and growth arrest. However, what controls p21 expression in keratinocytes remains uncertain. Hypoxia-inducible factor 1α (HIF-1α) does not only express a variety of genes essential for hypoxic adaptation, but also up-regulates p21 so as to slow down cell cycle under hypoxic conditions. In the present study, we examined the role of HIF-1α in p21-mediated growth arrest of keratinocyte. Keratinocyte proliferation was arrested in the G1 phase at a high cell density. p21 was also up-regulated in a cell density-dependent manner and was found to be highly expressed in epidermal keratinocytes of normal human skins. In addition, in the same specimens and cells, we noted robust HIF-1α expression. HIF-1α siRNAs inhibited p21 expression and released the G1 arrest. In vivo, moreover, the intradermal injection of HIF-1α siRNA attenuated p21 expression in rat epidermis and induced skin hyperplasia. Mechanistically, we propose that the production of mitochondrial reactive oxygen species and the activation of the MEK/ERK pathway are involved in the HIF-1α stabilization in keratinocytes. These results imply that HIF-1α functions as an up-stream player in the p21-mediated growth arrest of keratinocytes.

Original languageEnglish
Pages (from-to)323-333
Number of pages11
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Issue number2
Publication statusPublished - 2008 Feb
Externally publishedYes


  • Cell density
  • Growth arrest
  • Hypoxia-inducible factor 1α
  • Keratinocyte
  • p21

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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