Osteopontin-dependent CD44v6 expression and cell adhesion in HepG2 cells.

Published

Journal Article

The interaction of osteopontin (OPN) with CD44 and alphavbeta3-integrin has been implicated in numerous signal transduction pathways that may promote cancer metastasis. CD44v6 is a splice variant of CD44 which has been identified as a marker of cancer progression. In this study, immortalized liver carcinoma cells (HepG2) were used to examine the effect of OPN on two isoforms of CD44: CD44 standard (CD44 s) and CD44v6. Western blots demonstrated that OPN up-regulated plasma membrane CD44v6 protein expression in a concentration- and time-dependent fashion. CD44v6 levels returned to control levels when OPN-alphavbeta3-integrin binding was blocked by an RGD peptide or tyrosine kinase activity was inhibited. OPN significantly increased CD44v6 protein synthesis, while simultaneously decreasing protein degradation. Steady-state mRNA levels of both CD44s and CD44v6 were unaltered in the presence of OPN stimulation. OPN increased HepG2 in vitro adhesion to hyaluronate (HA); excess soluble HA extinguished OPN-mediated HepG2 adhesion, indicating CD44 dependence. In conclusion, OPN binds to the alphavbeta3-integrin to increase plasma membrane CD44v6 expression and augment in vitro adhesion to HA. This may contribute to the mechanism by which OPN enhances metastatic behavior in hepatocellular cancer cells.

Full Text

Duke Authors

Cited Authors

  • Gao, C; Guo, H; Downey, L; Marroquin, C; Wei, J; Kuo, PC

Published Date

  • December 2003

Published In

Volume / Issue

  • 24 / 12

Start / End Page

  • 1871 - 1878

PubMed ID

  • 12949055

Pubmed Central ID

  • 12949055

International Standard Serial Number (ISSN)

  • 0143-3334

Digital Object Identifier (DOI)

  • 10.1093/carcin/bgg139

Language

  • eng

Conference Location

  • England