Glioma cell proliferation controlled by ERK activity-dependent surface expression of PDGFRA

PLoS One. 2014 Jan 29;9(1):e87281. doi: 10.1371/journal.pone.0087281. eCollection 2014.

Abstract

Increased PDGFRA signaling is an essential pathogenic factor in many subtypes of gliomas. In this context the cell surface expression of PDGFRA is an important determinant of ligand sensing in the glioma microenvironment. However, the regulation of spatial distribution of PDGFRA in glioma cells remains poorly characterized. Here, we report that cell surface PDGFRA expression in gliomas is negatively regulated by an ERK-dependent mechanism, resulting in reduced proliferation of glioma cells. Glioma tumor tissues and their corresponding cell lines were isolated from 14 patients and analyzed by single-cell imaging and flow cytometry. In both cell lines and their corresponding tumor samples, glioma cell proliferation correlated with the extent of surface expression of PDGFRA. High levels of surface PDGFRA also correlated to high tubulin expression in glioma tumor tissue in vivo. In glioma cell lines, surface PDGFRA declined following treatment with inhibitors of tubulin, actin and dynamin. Screening of a panel of small molecule compounds identified the MEK inhibitor U0126 as a potent inhibitor of surface PDGFRA expression. Importantly, U0126 inhibited surface expression in a reversible, dose- and time-dependent manner, without affecting general PDGFRA expression. Treatment with U0126 resulted in reduced co-localization between PDGFRA and intracellular trafficking molecules e.g. clathrin, RAB11 and early endosomal antigen-1, in parallel with enhanced co-localization between PDGFRA and the Golgi cisternae maker, Giantin, suggesting a deviation of PDGFRA from the endosomal trafficking and recycling compartment, to the Golgi network. Furthermore, U0126 treatment in glioma cells induced an initial inhibition of ERK1/2 phosphorylation, followed by up-regulated ERK1/2 phosphorylation concomitant with diminished surface expression of PDGFRA. Finally, down-regulation of surface PDGFRA expression by U0126 is concordant with reduced glioma cell proliferation. These findings suggest that manipulation of spatial expression of PDGFRA can potentially be used to combat gliomas.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Butadienes / pharmacology
  • Cell Membrane / metabolism
  • Cell Proliferation*
  • Cytoskeleton / metabolism
  • Extracellular Signal-Regulated MAP Kinases / metabolism*
  • Gene Expression Regulation, Neoplastic
  • Glioma / metabolism*
  • Glioma / pathology
  • Humans
  • Nitriles / pharmacology
  • Protein Kinase Inhibitors / pharmacology
  • Protein Transport
  • Receptor, Platelet-Derived Growth Factor alpha / metabolism*
  • Tumor Cells, Cultured
  • Vesicular Transport Proteins / metabolism
  • rab GTP-Binding Proteins / metabolism

Substances

  • Butadienes
  • Nitriles
  • Protein Kinase Inhibitors
  • U 0126
  • Vesicular Transport Proteins
  • early endosome antigen 1
  • Receptor, Platelet-Derived Growth Factor alpha
  • Extracellular Signal-Regulated MAP Kinases
  • rab11 protein
  • rab GTP-Binding Proteins

Grants and funding

This study was supported by National Natural Science Foundation of China (grant 81072080), international collaborative program of the Ministry of Science and Technology of China (grant 2012DFA30470), and the Hans and Marit Rausing Charitable Foundation. The study was also supported by grants to E.R. from the Swedish Research Council (project 12234), clinical research grants (ALF). EZ’s position receives funding from the EU Integrated project BetaBat and a collaborative SRC grant, as well as the Swedish Strategic Research EXODIAB. This work was done using imaging equipment financed by the Knut and Alice Wallenberg foundation. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.