PTEN regulates p300-dependent hypoxia-inducible factor 1 transcriptional activity through Forkhead transcription factor 3a (FOXO3a)

Brooke M. Emerling, Frank Weinberg, Juinn Lin Liu, Tak W. Mak, Navdeep S. Chandel

Research output: Contribution to journalArticle

138 Scopus citations

Abstract

The tumor suppressor PTEN is mutated or deleted in many tumors, causing the activation of the PI3K pathway. Here, we show that the loss of PTEN increases the transcriptional activity of hypoxia-inducible factor 1 (HIF-1) through the inactivation of Forkhead transcription factors (FOXO) in PTEN-null cells. Reintroduction of PTEN into the nucleus, overexpression of a nonphosphorylatable FOXO3a, which accumulates in the nucleus, or inhibition of nuclear export of FOXO3a by leptomycin B represses HIF-1 transcriptional activity in PTEN-null cells. HIF-1 transcriptional activity increases in PTEN-positive cells depleted of FOXO3a with siRNA. PTEN and FOXO3a regulate the transactivation domain of HIF-1α. Chromatin immunoprecipitation indicates that FOXO3a complexes with HIF-1α and p300 on the Glut-1 promoter, a HIF-1 target gene. Overexpression of p300 reverses FOXO3a-mediated repression of HIF-1 transcriptional activity. Coimmunoprecipitation and GAL4-HIF-1α transactivation assays reveal that FOXO3a interferes with p300-dependent HIF-1 transcriptional activity. Thus, FOXO3a negatively regulates HIF-1 transcriptional activity.

Original languageEnglish (US)
Pages (from-to)2622-2627
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume105
Issue number7
DOIs
StatePublished - Feb 19 2008

Keywords

  • Glioblastoma
  • Pi3-kinase
  • VEGF

ASJC Scopus subject areas

  • General

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