Plexin-B2 promotes invasive growth of malignant glioma

Oncotarget. 2015 Mar 30;6(9):7293-304. doi: 10.18632/oncotarget.3421.

Abstract

Invasive growth is a major determinant of the high lethality of malignant gliomas. Plexin-B2, an axon guidance receptor important for mediating neural progenitor cell migration during development, is upregulated in gliomas, but its function therein remains poorly understood. Combining bioinformatic analyses, immunoblotting and immunohistochemistry of patient samples, we demonstrate that Plexin-B2 is consistently upregulated in all types of human gliomas and that its expression levels correlate with glioma grade and poor survival. Activation of Plexin-B2 by Sema4C ligand in glioblastoma cells induced actin-based cytoskeletal dynamics and invasive migration in vitro. This proinvasive effect was associated with activation of the cell motility mediators RhoA and Rac1. Furthermore, costimulation of Plexin-B2 and the receptor tyrosine kinase Met led to synergistic Met phosphorylation. In intracranial glioblastoma transplants, Plexin-B2 knockdown hindered invasive growth and perivascular spreading, and resulted in decreased tumor vascularity. Our results demonstrate that Plexin-B2 promotes glioma invasion and vascularization, and they identify Plexin-B2 as a potential novel prognostic marker for glioma malignancy. Targeting the Plexin-B2 pathway may represent a novel therapeutic approach to curtail invasive growth of glioblastoma.

Keywords: glioma invasion; plexin; semaphorin; tumor vasculature.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomarkers, Tumor
  • Brain Neoplasms / pathology*
  • Cell Line, Tumor
  • Cell Movement
  • Computational Biology
  • GTP Phosphohydrolases / metabolism
  • Gene Expression Profiling
  • Gene Expression Regulation, Neoplastic*
  • Glioblastoma
  • Glioma / metabolism*
  • Humans
  • Neoplasm Invasiveness
  • Nerve Tissue Proteins / metabolism*
  • Oligonucleotide Array Sequence Analysis
  • Phosphorylation
  • Semaphorins / metabolism
  • Up-Regulation
  • rho-Associated Kinases / metabolism

Substances

  • Biomarkers, Tumor
  • Nerve Tissue Proteins
  • SEMA4A protein, human
  • Semaphorins
  • plexin B2 protein, human
  • rho-Associated Kinases
  • GTP Phosphohydrolases