Human U87 astrocytoma cell invasion induced by interaction of βig-h3 with integrin α5β1 involves calpain-2

PLoS One. 2012;7(5):e37297. doi: 10.1371/journal.pone.0037297. Epub 2012 May 21.

Abstract

It is known that βig-h3 is involved in the invasive process of many types of tumors, but its mechanism in glioma cells has not been fully clarified. Using immunofluorescent double-staining and confocal imaging analysis, and co-immunoprecipitation assays, we found that βig-h3 co-localized with integrin α5β1 in U87 cells. We sought to elucidate the function of this interaction by performing cell invasion assays and gelatin zymography experiments. We found that siRNA knockdowns of βig-h3 and calpain-2 impaired cell invasion and MMP secretion. Moreover, βig-h3, integrins and calpain-2 are known to be regulated by Ca(2+), and they are also involved in tumor cell invasion. Therefore, we further investigated if calpain-2 was relevant to βig-h3-integrin α5β1 interaction to affect U87 cell invasion. Our data showed that βig-h3 co-localized with integrin α5β1 to enhance the invasion of U87 cells, and that calpain-2, is involved in this process, acting as a downstream molecule.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Astrocytes / metabolism*
  • Astrocytoma / metabolism*
  • Calpain / genetics
  • Calpain / metabolism*
  • Cell Adhesion / physiology
  • Cell Line, Tumor
  • Cell Movement / physiology*
  • Extracellular Matrix Proteins / genetics
  • Extracellular Matrix Proteins / metabolism*
  • Humans
  • Integrin alpha5beta1 / genetics
  • Integrin alpha5beta1 / metabolism*
  • RNA, Small Interfering
  • Transforming Growth Factor beta / genetics
  • Transforming Growth Factor beta / metabolism*

Substances

  • Extracellular Matrix Proteins
  • Integrin alpha5beta1
  • RNA, Small Interfering
  • Transforming Growth Factor beta
  • betaIG-H3 protein
  • Calpain
  • CAPN2 protein, human