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A proprotein convertase/MMP-14 proteolytic cascade releases a novel 40 kDa vasculostatin from tumor suppressor BAI1

S M Cork1, B Kaur, N S Devi

  • 1Department of Neurosurgery, Laboratory of Molecular Neuro-Oncology, Emory University School of Medicine, Atlanta, GA, USA.

Oncogene
|February 15, 2012
PubMed

Insights

Brain-specific angiogenesis inhibitor 1 (BAI1) is cleaved to release Vasculostatin-40, a fragment that inhibits tumor angiogenesis. This novel processing involves specific proteases, offering new therapeutic targets for cancer and vascular diseases.

Area of Science:

  • Molecular Biology
  • Oncology
  • Biochemistry

Background:

  • Brain-specific angiogenesis inhibitor 1 (BAI1) is a seven-transmembrane protein implicated as a tumor suppressor.
  • BAI1's role in cancer is recognized, but its regulatory mechanisms and anti-cancer effects are poorly understood.

Purpose of the Study:

  • To elucidate the post-translational regulation of BAI1.
  • To identify the molecular mechanisms underlying BAI1's anti-cancer properties.

Main Methods:

  • Investigated BAI1 proteolytic processing using biochemical assays.
  • Identified proteases involved in BAI1 cleavage, including furin and matrix metalloproteinase-14 (MMP-14).
  • Assessed the anti-angiogenic activity of the released BAI1 fragment.

Main Results:

  • Demonstrated extracellular N-terminal cleavage of BAI1 to yield Vasculostatin-40 (40-kDa fragment).
  • Established a two-step protease cascade: proprotein convertases (furin) activate MMP-14, which then cleaves BAI1.
  • Confirmed Vasculostatin-40 inhibits angiogenesis.

Conclusions:

  • BAI1 activity is regulated by a novel proteolytic processing pathway involving cancer-associated proteases.
  • This mechanism provides new insights into BAI1 function and regulation in cancer.
  • Identified potential therapeutic strategies targeting BAI1 processing for cancer and vascular diseases.

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