Hypoxia-induced secretion of platelet-derived growth factor-BB by hepatocellular carcinoma cells increases activated hepatic stellate cell proliferation, migration and expression of vascular endothelial growth factor-A

Mol Med Rep. 2015 Jan;11(1):691-7. doi: 10.3892/mmr.2014.2689. Epub 2014 Oct 17.

Abstract

Angiogenesis has an important function in the proliferation and metastasis of hepatocellular carcinoma (HCC) under a hypoxic tumor microenvironment. Activated hepatic stellate cells (HSCs) infiltrate the stroma of liver tumors and potently increase angiogenesis through tumor-stromal interactions, however, the exact mechanism by which this occurs is unknown. The present study aimed to investigate the paracrine effects of HCC-derived platelet-derived growth factor-BB (PDGF-BB) on HSCs under hypoxic conditions. It was demonstrated that PDGF-BB expression was markedly increased in HepG2 cells exposed to hypoxia. Conditioned medium (CM) from HepG2 cells stimulated LX-2 cell proliferation, migration and vascular endothelial growth factor-A (VEGF-A) expression. It was then determined that blocking PDGF-BB expression in HepG2-CM abolished these effects on LX-2 cells. The ectopic expression of PDGF-BB in HepG2 cells strongly affected LX-2 cell proliferation, migration and VEGF-A expression. In conclusion, the present study suggests that hypoxia-induced PDGF-BB secretion by HCC cells stimulates HSCs to accumulate and proliferate in the tumor stroma and the enhanced VEGF-A expression in HSCs may promote HCC angiogenesis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Becaplermin
  • Carcinoma, Hepatocellular / genetics
  • Carcinoma, Hepatocellular / metabolism*
  • Carcinoma, Hepatocellular / pathology
  • Cell Line, Tumor
  • Cell Movement
  • Cell Proliferation
  • Coculture Techniques
  • Gene Expression
  • Hepatic Stellate Cells / metabolism*
  • Humans
  • Hypoxia
  • Liver Neoplasms / genetics
  • Liver Neoplasms / metabolism*
  • Liver Neoplasms / pathology
  • Proto-Oncogene Proteins c-sis / genetics
  • Proto-Oncogene Proteins c-sis / metabolism*
  • Receptor, Platelet-Derived Growth Factor beta / genetics
  • Receptor, Platelet-Derived Growth Factor beta / metabolism
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism*

Substances

  • Proto-Oncogene Proteins c-sis
  • Vascular Endothelial Growth Factor A
  • Becaplermin
  • Receptor, Platelet-Derived Growth Factor beta