VEGF-C differentially regulates VEGF-A expression in ocular and cancer cells; promotes angiogenesis via RhoA mediated pathway

Angiogenesis. 2011 Sep;14(3):371-80. doi: 10.1007/s10456-011-9221-5. Epub 2011 Jun 23.

Abstract

Vascular angiogenesis is regulated by a number of cytokines of which vascular endothelial growth factor (VEGF)-A/and its receptor vascular endothelial growth factor receptor 2 (VEGFR2) play an indisputable role. Similarly lymphangiogenesis is regulated by VEGF-C and its receptor VEGFR3. Currently for treating vasculogenesis diseases such as proliferative retinopathies and cancer, a number of anti-VEGF-A therapies are approved for clinical use. Although clinical efficacies achieved are remarkable, they are found to be transitory in nature, followed by restoration of anti-VEGF therapy resistant angiogenesis. Recently the regulatory role of VEGF-C in initiating and potentiating neo-angiogenesis has been uncovered. Although the interactive nature of VEGF-A and C is known, the dynamics of their expression under knockdown conditions is yet to be established. Here in this study we have utilized siRNA to knockdown both VEGF-A and C either independently or in combination. Analysis of VEGF-A and C expression (only in cancer cell lines MCF7, A549 and H460 but not in the ocular cell line RPE19) has shown enhanced expression levels of VEGF-C with increase in knockdown of VEGF-A. However, VEGF-C knockdown has resulted in decreased expression levels of VEGF-A both in RPE19 and MCF7 cells in a dose dependent manner. In addition, VEGF-C knockdown also resulted in decreased expression of RhoA. Further, knockdown studies of RhoA even with supplementation of VEGF-C or A has resulted in decreased endothelial cell proliferation and stress fiber formation, indicating that VEGF-C does promote angiogenesis via RhoA mediated pathway.

MeSH terms

  • Cell Line, Tumor
  • Cell Proliferation
  • Eye / metabolism*
  • Eye / pathology
  • Eye Proteins / genetics
  • Eye Proteins / metabolism*
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Neoplasms / genetics
  • Neoplasms / metabolism*
  • Neoplasms / pathology
  • Neovascularization, Pathologic / genetics
  • Neovascularization, Pathologic / metabolism*
  • Neovascularization, Pathologic / pathology
  • RNA, Small Interfering / genetics
  • Vascular Endothelial Growth Factor A / biosynthesis*
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor C / genetics
  • Vascular Endothelial Growth Factor C / metabolism*
  • rhoA GTP-Binding Protein / genetics
  • rhoA GTP-Binding Protein / metabolism*

Substances

  • Eye Proteins
  • Neoplasm Proteins
  • RNA, Small Interfering
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Vascular Endothelial Growth Factor C
  • RHOA protein, human
  • rhoA GTP-Binding Protein