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Hypoxia-inducible factor 1{alpha} is a new target of microphthalmia-associated transcription factor (MITF) in

Roser Buscà1, Edurne Berra, Cédric Gaggioli

  • 1INSERM U597, Biologie et physiopathologie des cellules mélanocytaires, Faculty of Medicine, 06107 Nice cedex 2, France. busca@unice.fr

The Journal of Cell Biology
|June 29, 2005
PubMed

Insights

Alpha-melanocyte stimulating hormone (alpha-MSH) activates the Hif1a gene in melanocytes via cAMP and microphthalmia-associated transcription factor (MITF). This pathway, involving HIF1alpha, promotes melanoma cell survival and progression.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Cancer Research

Background:

  • Alpha-melanocyte stimulating hormone (alpha-MSH) regulates melanocyte differentiation and melanoma development through the cAMP pathway.
  • The hypoxia-inducible factor 1alpha (HIF1alpha) pathway is implicated in cancer progression.

Purpose of the Study:

  • To investigate the role of the cAMP pathway and microphthalmia-associated transcription factor (MITF) in regulating Hif1a gene expression in melanocytes and melanoma cells.
  • To determine if HIF1alpha plays a role in melanoma cell survival.

Main Methods:

  • Investigated the effect of cAMP on Hif1a gene transcription in melanocytes.
  • Analyzed the binding of MITF to the Hif1a promoter using luciferase assays.
  • Assessed the impact of MITF knockdown and overexpression on Hif1a expression.
  • Evaluated the role of HIF1alpha in melanoma cell survival.

Main Results:

  • cAMP transcriptionally activates Hif1a in a melanocyte-specific manner, increasing HIF1alpha protein and stimulating Vegf expression.
  • MITF directly binds to the Hif1a promoter and enhances its transcriptional activity.
  • MITF mediates the cAMP-induced stimulation of Hif1a expression.
  • HIF1alpha plays a pro-survival role in melanocytes and melanoma cells.

Conclusions:

  • Hif1a is a novel MITF target gene, and MITF acts as a signal transducer for the alpha-MSH/cAMP pathway in melanocytes and melanoma.
  • The alpha-MSH/cAMP/MITF/HIF1alpha axis may contribute to melanoma progression by promoting cell survival.

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