Targeting SRPK1 to control VEGF-mediated tumour angiogenesis in metastatic melanoma

Br J Cancer. 2014 Jul 29;111(3):477-85. doi: 10.1038/bjc.2014.342. Epub 2014 Jul 10.


Background: Current therapies for metastatic melanoma are targeted either at cancer mutations driving growth (e.g., vemurafenib) or immune-based therapies (e.g., ipilimumab). Tumour progression also requires angiogenesis, which is regulated by VEGF-A, itself alternatively spliced to form two families of isoforms, pro- and anti-angiogenic. Metastatic melanoma is associated with a splicing switch to pro-angiogenic VEGF-A, previously shown to be regulated by SRSF1 phosphorylation by SRPK1. Here, we show a novel approach to preventing angiogenesis-targeting splicing factor kinases that are highly expressed in melanomas.

Methods: We used RT-PCR, western blotting and immunohistochemistry to investigate SRPK1, SRSF1 and VEGF expression in tumour cells, and in vivo xenograft assays to investigate SRPK1 knockdown and inhibition in vivo.

Results: In both uveal and cutaneous melanoma cell lines, SRPK1 was highly expressed, and inhibition of SRPK1 by knockdown or with pharmacological inhibitors reduced pro-angiogenic VEGF expression maintaining the production of anti-angiogenic VEGF isoforms. Both pharmacological SRPK1 inhibitors and SRPK1 knockdown reduced growth of human melanomas in vivo, but neither affected cell proliferation in vitro.

Conclusions: These results suggest that selective blocking of pro-angiogenic isoforms by inhibiting splice-site selection with SRPK1 inhibitors reduces melanoma growth. SRPK1 inhibitors may be used as therapeutic agents.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inhibitors / pharmacology
  • Animals
  • Cell Line, Tumor
  • Gene Knockdown Techniques
  • Humans
  • Melanoma / drug therapy
  • Melanoma / metabolism*
  • Melanoma / secondary
  • Mice
  • Mice, Nude
  • Molecular Targeted Therapy
  • Neovascularization, Pathologic / metabolism*
  • Niacinamide / analogs & derivatives
  • Niacinamide / pharmacology
  • Piperidines / pharmacology
  • Protein Serine-Threonine Kinases / antagonists & inhibitors
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism*
  • RNA Splicing
  • Skin Neoplasms / drug therapy
  • Skin Neoplasms / metabolism*
  • Skin Neoplasms / pathology
  • Tumor Burden
  • Vascular Endothelial Growth Factor A / physiology*
  • Xenograft Model Antitumor Assays


  • Angiogenesis Inhibitors
  • Piperidines
  • SRPIN340
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Niacinamide
  • SRPK1 protein, human
  • Protein Serine-Threonine Kinases