Hypoxia-induced nucleophosmin protects cell death through inhibition of p53

June Li, Xiaoling Zhang, Daniel P. Sejas, Grover C. Bagby, Qishen Pang

Research output: Contribution to journalArticlepeer-review

129 Scopus citations


Nucleophosmin (NPM) is a multifunctional protein that is overexpressed in actively proliferating cells and cancer cells. Here we report that this proliferation-promoting protein is strongly induced in response to hypoxia in human normal and cancer cells. Up-regulation of NPM is hypoxia-inducible factor-1 (HIF-1)-dependent. The NPM promoter encodes a functional HIF-1-responsive element that can be activated by hypoxia or forced expression of HIF-1α. Suppression of NPM expression by small interfering RNA targeting NPM increases hypoxia-induced apoptosis, whereas overexpression of NPM protects against hypoxic cell death of wild-type but not p53-null cells. Moreover, NPM inhibits hypoxia-induced p53 phosphorylation at Ser-15 and interacts with p53 in hypoxic cells. Thus, this study not only demonstrates hypoxia regulation of a proliferation-promoting protein but also suggests that hypoxia-driven cancer progression may require increased expression of NPM to suppress p53 activation and maintain cell survival.

Original languageEnglish (US)
Pages (from-to)41275-41279
Number of pages5
JournalJournal of Biological Chemistry
Issue number40
StatePublished - Oct 1 2004
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology


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