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Hypoxia and RAS-signaling pathways converge on, and cooperatively downregulate, the RECK tumor-suppressor protein

F Loayza-Puch1, Y Yoshida, T Matsuzaki

  • 1Department of Molecular Oncology, Kyoto University Graduate School of Medicine, Kyoto, Japan.

Oncogene
|February 16, 2010
PubMed

Insights

Tumor suppressor RECK is downregulated by microRNAs (miRNAs) activated by hypoxia and RAS signaling. This miRNA-mediated repression promotes cancer cell malignancy and metastasis.

Area of Science:

  • Oncology
  • Molecular Biology
  • Gene Regulation

Background:

  • Cancer cells exhibit distinct gene expression profiles.
  • MicroRNA (miRNA) signatures are emerging as crucial biomarkers and therapeutic targets in cancer.
  • RECK, a membrane-anchored protease regulator, is frequently downregulated in cancers and suppresses tumor malignancy.

Purpose of the Study:

  • To investigate the regulatory mechanisms controlling RECK expression in cancer.
  • To identify specific miRNAs targeting RECK.
  • To elucidate the signaling pathways that modulate these miRNAs and impact RECK levels.

Main Methods:

  • Bioinformatic analysis to predict miRNA target sites on RECK.
  • Reporter assays to validate miRNA targeting of RECK.
  • Mutation analysis of RECK to assess the impact of miRNA binding sites on its tumor-suppressor function.
  • Analysis of miRNA expression in response to hypoxia and RAS/ERK signaling.

Main Results:

  • RECK was identified as a direct target of miR-15b/16, miR-21, and miR-372/373.
  • RECK mutants lacking miRNA target sites exhibited enhanced tumor and metastasis suppression.
  • Hypoxia upregulates miR-372/373 via HIF1alpha and TWIST1.
  • RAS/ERK signaling upregulates miR-21.
  • These pathways converge to downregulate RECK through specific miRNAs.

Conclusions:

  • Hypoxia and RAS signaling pathways cooperatively suppress the tumor suppressor RECK via specific miRNAs.
  • This miRNA-mediated downregulation of RECK promotes malignant cell behavior and metastasis.
  • Targeting these miRNA-RECK interactions could offer novel therapeutic strategies for cancer.

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