Loss of fibulin-5 binding to β1 integrins inhibits tumor growth by increasing the level of ROS

Marie K. Schluterman, Shelby L. Chapman, Grzegorz Korpanty, Kiyoshi Ozumi, Tohru Fukai, Hiromi Yanagisawa, Rolf A. Brekken

Research output: Contribution to journalArticlepeer-review

42 Scopus citations

Abstract

Tumor survival depends in part on the ability of tumor cells to transform the surrounding extracellular matrix (ECM) into an environment conducive to tumor progression. Matricellular proteins are secreted into the ECM and impact signaling pathways that are required for pro-tumorigenic activities such as angiogenesis. Fibulin-5 (Fbln5) is a matricellular protein that was recently shown to regulate angiogenesis; however, its effect on tumor angiogenesis and thus tumor growth is currently unknown. We report that the growth of pancreatic tumors and tumor angiogenesis is suppressed in Fbln5-null (Fbln5-/-) mice compared with wild-type (WT) littermates. Furthermore, we observed an increase in the level of reactive oxygen species (ROS) in tumors grown in Fbln5-/- animals. Increased ROS resulted in elevated DNA damage, increased apoptosis of endothelial cells within the tumor, and represented the underlying cause for the reduction in angiogenesis and tumor growth. In vitro, we identified a novel pathway by which Fbln5 controls ROS production through a mechanism that is dependent on b1 integrins. These results were validated in Fbln5RGE/RGE mice, which harbor a point mutation in the integrin-binding RGD motif of Fbln5, preventing its interaction with integrins. Tumor growth and angiogenesis was reduced in Fbln5RGE/RGE mice, however treatment with an antioxidant rescued angiogenesis and elevated tumor growth to WT levels. These findings introduce a novel function for Fbln5 in the regulation of integrin-induced ROS production and establish a rationale for future studies to examine whether blocking Fbln5 function could be an effective anti-tumor strategy, alone or in combination with other therapies.

Original languageEnglish (US)
Pages (from-to)333-342
Number of pages10
JournalDMM Disease Models and Mechanisms
Volume3
Issue number5-6
DOIs
StatePublished - May 2010

ASJC Scopus subject areas

  • Neuroscience (miscellaneous)
  • Medicine (miscellaneous)
  • Immunology and Microbiology (miscellaneous)
  • Biochemistry, Genetics and Molecular Biology(all)

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