An autocrine loop directed by the vascular endothelial growth factor promotes invasiveness of human melanoma cells

Int J Oncol. 2005 Dec;27(6):1625-32.

Abstract

The vascular endothelial growth factor-A (VEGF-A) is a cytokine that promotes angiogenesis through the activation of two tyrosine kinase receptors, VEGFR-1 and VEGFR-2, on vascular endothelial cells. Moreover, several experimental evidences indicate that VEGF-A may also play a role in tumor progression by acting on neoplastic cells expressing VEGFRs. In this study we show that human melanoma cells that simultaneously produce VEGF-A and express VEGFRs exhibit a higher spontaneous ability to invade the extracellular matrix (ECM) than melanoma cells not expressing either VEGF-A or VEGFRs. Exposure of VEGFR expressing melanoma cells to exogenous VEGF-A further increases their ability to invade the ECM. Moreover, an inhibitor of VEGFR tyrosine kinase activity is able to abrogate VEGF-A-induced stimulation of ECM invasion. A cell clone (13443/N2) derived from a VEGF-A responsive melanoma cell line and expressing high levels of VEGFR-2 invades the ECM eight-fold more efficiently than a cell clone derived from the same cell line and expressing extremely low levels of the receptor. Exposure of 13443/N2 cells to VEGF-E, which selectively binds and activates VEGFR-2, increases their ability to invade the ECM. Finally, the expression of the VEGF-A mRNA antisense sequence in 13443/N2 cells markedly reduces the release of VEGF-A and ECM invasion. In conclusion, our data show for the first time that a VEGF-A-driven autocrine loop promotes human melanoma cell ability to invade the ECM, and strongly support the hypothesis that activation of VEGFR-2 plays a primary role in this process.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Line, Tumor
  • Cell Movement / drug effects
  • Cell Movement / physiology*
  • Dose-Response Relationship, Drug
  • Extracellular Matrix / metabolism
  • Gene Expression Regulation
  • Humans
  • Melanoma / metabolism
  • Melanoma / pathology
  • Melanoma / physiopathology
  • Neoplasm Invasiveness
  • Oligonucleotides, Antisense / genetics
  • Plasmids / genetics
  • Protein Kinase Inhibitors / pharmacology
  • Receptors, Vascular Endothelial Growth Factor / antagonists & inhibitors
  • Receptors, Vascular Endothelial Growth Factor / physiology*
  • Transfection
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor A / pharmacology*
  • Vascular Endothelial Growth Factor Receptor-1 / antagonists & inhibitors
  • Vascular Endothelial Growth Factor Receptor-1 / physiology
  • Vascular Endothelial Growth Factor Receptor-2 / antagonists & inhibitors
  • Vascular Endothelial Growth Factor Receptor-2 / physiology

Substances

  • Oligonucleotides, Antisense
  • Protein Kinase Inhibitors
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Receptors, Vascular Endothelial Growth Factor
  • Vascular Endothelial Growth Factor Receptor-1
  • Vascular Endothelial Growth Factor Receptor-2