Inhibition of aquaporin-1 dependent angiogenesis impairs tumour growth in a mouse model of melanoma

J Mol Med (Berl). 2013 May;91(5):613-23. doi: 10.1007/s00109-012-0977-x. Epub 2012 Nov 30.


Prohibiting angiogenesis is an important therapeutic approach for fighting cancer and other angiogenic related diseases. Research focused on proteins that regulate abnormal angiogenesis has attracted intense interest in both academia and industry. Such proteins are able to target several angiogenic factors concurrently, thereby increasing the possibility of therapeutic success. Aquaporin-1 (AQP1) is a water channel membrane protein that promotes tumour angiogenesis by allowing faster endothelial cell migration. In this study we test the hypothesis that AQP1 inhibition impairs tumour growth in a mouse model of melanoma. After validating the inhibitor efficacy of two different AQP1 specific siRNAs in cell cultures, RNA interference experiments were performed by intratumoural injections of AQP1 siRNAs in mice. After 6 days of treatment, AQP1 siRNA treated tumours showed a 75 % reduction in volume when compared to controls. AQP1 protein level, in AQP1 knockdown tumours, was around 75 % that of the controls and was associated with a significant 40 % reduced expression of the endothelial marker, Factor VIII. Immunofluorescence analysis of AQP1 siRNA treated tumours showed a significantly lower microvessel density. Time course experiments demonstrated that repeated injections of AQP1 siRNA over time are effective in sustaining the inhibition of tumour growth. Finally, we have confirmed the role of AQP1 in sustaining an active endothelium during angiogenesis and we have shown that AQP1 reduction causes an increase in VEGF levels. In conclusion, this study validates AQP1 as a pro-angiogenic protein, relevant for the therapy of cancer and other angiogenic-related diseases such as psoriasis, endometriosis, arthritis and atherosclerosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Aquaporin 1 / antagonists & inhibitors
  • Aquaporin 1 / genetics*
  • Aquaporin 1 / metabolism
  • Biomarkers / metabolism
  • Cell Proliferation
  • Factor VIII / genetics
  • Factor VIII / metabolism
  • Gene Expression
  • HeLa Cells
  • Humans
  • Injections, Intralesional
  • Male
  • Melanoma, Experimental / blood supply*
  • Melanoma, Experimental / genetics*
  • Melanoma, Experimental / pathology
  • Mice
  • Mice, Inbred C57BL
  • Molecular Targeted Therapy
  • Neovascularization, Pathologic
  • RNA Interference
  • RNA, Small Interfering / genetics*
  • RNA, Small Interfering / metabolism
  • Skin Neoplasms / blood supply*
  • Skin Neoplasms / genetics*
  • Skin Neoplasms / pathology
  • Tumor Burden
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism


  • AQP1 protein, human
  • Biomarkers
  • RNA, Small Interfering
  • Vascular Endothelial Growth Factor A
  • vascular endothelial growth factor A, mouse
  • Aquaporin 1
  • Factor VIII