Tumor microvasculature with endothelial fenestrations in VHL null clear cell renal cell carcinomas as a potent target of anti-angiogenic therapy

Cancer Sci. 2012 Nov;103(11):2027-37. doi: 10.1111/j.1349-7006.2012.02412.x. Epub 2012 Oct 10.


Vascular endothelial growth factor (VEGF)-targeted therapies show significant antitumor effects for advanced clear cell renal cell carcinomas (CC-RCCs). Previous studies using VEGF inhibitors in mice models revealed that VEGF-dependent capillaries were characterized by the existence of endothelial fenestrations (EFs). In this study, we revealed that capillaries with abundant EFs did exist, particularly in CC-RCCs harboring VHL mutation. This finding was recapitulated in mice xenograft models, in which tumors from VHL null cells showed more abundant EFs compared to those from VHL wild-type cells. Importantly, treatment with bevacizumab resulted in a significant decrease of tumor size established from VHL null cells. Additionally, a significant reduction of EFs and microvessel density was observed in VHL null tumors. Indeed, xenograft from 786-O/mock (pRC3) cells developed four times more abundant EFs than that from 786-O/VHL (WT8). However, introduction of the constitutively active form of hypoxia-inducible factor (HIF)-2α to WT8 cells failed to either augment the number of EFs or restore the sensitivity to bevacizumab in mice xenograft, irrespective of the equivalent production of VEGF to 786-O/mock cells. These results indicated that HIF-2α independent factors also play significant roles in the development of abundant EFs. In fact, several angiogenesis-related genes including CCL2 were upregulated in 786-O cells in a HIF-2α independent manner. Treatment with CCL2 neutralizing antibody caused significant reduction of capillaries with EFs in 786-O xenograft, indicating that they were also sensitive to CCL2 inhibition as well as VEGF. Collectively, these results strongly indicated that capillaries with distinctive phenotype developed in VHL null CC-RCCs are potent targets for anti-angiogenic therapy.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inhibitors / pharmacology*
  • Animals
  • Antibodies, Monoclonal, Humanized / pharmacology
  • Basic Helix-Loop-Helix Transcription Factors / genetics
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Bevacizumab
  • Capillaries / drug effects
  • Capillaries / metabolism
  • Capillaries / pathology
  • Carcinoma, Renal Cell / blood supply*
  • Carcinoma, Renal Cell / drug therapy*
  • Carcinoma, Renal Cell / genetics
  • Carcinoma, Renal Cell / metabolism
  • Cell Hypoxia / genetics
  • Chemokine CCL2 / genetics
  • Chemokine CCL2 / metabolism
  • Female
  • Humans
  • Kidney Neoplasms / blood supply*
  • Kidney Neoplasms / drug therapy*
  • Kidney Neoplasms / genetics
  • Kidney Neoplasms / metabolism
  • Male
  • Mice
  • Mice, Inbred BALB C
  • Mice, Nude
  • Microvessels / drug effects
  • Microvessels / metabolism
  • Microvessels / pathology
  • Middle Aged
  • Neovascularization, Pathologic / drug therapy
  • Neovascularization, Pathologic / genetics
  • Neovascularization, Pathologic / metabolism
  • Neovascularization, Pathologic / pathology
  • Tumor Cells, Cultured
  • Vascular Endothelial Growth Factor A / antagonists & inhibitors
  • Vascular Endothelial Growth Factor A / metabolism
  • Von Hippel-Lindau Tumor Suppressor Protein / genetics*
  • Von Hippel-Lindau Tumor Suppressor Protein / metabolism


  • Angiogenesis Inhibitors
  • Antibodies, Monoclonal, Humanized
  • Basic Helix-Loop-Helix Transcription Factors
  • CCL2 protein, human
  • Chemokine CCL2
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • endothelial PAS domain-containing protein 1
  • Bevacizumab
  • Von Hippel-Lindau Tumor Suppressor Protein
  • VHL protein, human