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Critical role for matrix metalloproteinase-9 in platelet-activating factor-induced experimental tumor metastasis

Hyun-Mi Ko1, Jee-Hae Kang, Bongnam Jung

  • 1Department of Biological Sciences, College of Natural Sciences, Chonnam National University, Kwangju 500-757, Republic of Korea.

International Journal of Cancer
|December 26, 2006
PubMed

Insights

Platelet-activating factor (PAF) promotes melanoma lung metastasis by increasing matrix metalloproteinase-9 (MMP-9) expression. Inhibiting MMP-9 effectively blocks this PAF-induced metastasis, highlighting MMP-9

Area of Science:

  • Biochemistry
  • Oncology
  • Cell Biology

Background:

  • Platelet-activating factor (PAF) is implicated in inflammatory and metastatic processes.
  • Matrix metalloproteinases (MMPs), particularly MMP-2 and MMP-9, are crucial in extracellular matrix remodeling and cancer metastasis.
  • The specific roles of MMP-2 and MMP-9 in PAF-induced pulmonary metastasis require elucidation.

Purpose of the Study:

  • To investigate the involvement of matrix metalloproteinase (MMP)-2 and MMP-9 in platelet-activating factor (PAF)-induced experimental pulmonary metastasis of B16F10 melanoma cells.
  • To determine the regulatory pathways (NF-kappaB, AP-1) controlling MMP expression in this model.
  • To assess the therapeutic potential of MMP inhibitors in preventing PAF-mediated lung metastasis.

Main Methods:

  • Murine melanoma cells (B16F10) were used in an experimental pulmonary metastasis model.
  • Platelet-activating factor (PAF) was administered to induce metastasis.
  • mRNA expression, protein levels, and enzymatic activities of MMP-2 and MMP-9 were quantified.
  • Inhibitors of NF-kappaB and AP-1 signaling pathways were employed.
  • Immunohistochemistry was used to localize MMP-9 and MMP-2 expression.
  • The effect of specific MMP-2 and MMP-9 inhibitors on B16F10 metastasis was evaluated.

Main Results:

  • PAF administration significantly increased lung mRNA, protein levels, and activity of both MMP-2 and MMP-9.
  • MMP-9 expression was notably stronger than MMP-2 and was regulated by both NF-kappaB and AP-1.
  • MMP-2 expression was regulated solely by AP-1.
  • Immunohistochemistry showed MMP-9 in bronchial epithelial cells and blood vessel walls, while MMP-2 was confined to bronchial epithelial cells.
  • PAF-induced B16F10 pulmonary metastasis was significantly inhibited by NF-kappaB and c-jun (AP-1) inhibitors.
  • A specific MMP-9 inhibitor completely abolished PAF-induced B16F10 metastasis, whereas an MMP-2 inhibitor had no effect.

Conclusions:

  • Matrix metalloproteinase-9 (MMP-9), regulated by NF-kappaB and AP-1 signaling, plays a critical role in PAF-induced enhancement of pulmonary melanoma metastasis.
  • MMP-9 is a key mediator in the process of PAF-driven melanoma cell dissemination to the lungs.
  • Targeting MMP-9 presents a potential therapeutic strategy for inhibiting PAF-mediated melanoma lung metastasis.

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