Regulation of pro-angiogenic tissue factor expression in hypoxia-induced human lung cancer cells

Oncol Rep. 2013 Jul;30(1):462-70. doi: 10.3892/or.2013.2413. Epub 2013 Apr 22.

Abstract

Alternative splicing is a key regulatory mechanism for cellular metabolism controlling cell proliferation and angiogenesis, both of which are crucial processes for tumorigenesis under hypoxia. Human cells express two tissue factor (TF) isoforms, alternatively spliced TF (asTF) and 'full length' TF (flTF). flTF is the major source of thrombogenicity whereas, the function of soluble asTF, particularly in cancer, is widely unknown. In the present study, we examined the impact of alternative splicing on the pro-angiogenic potential and the TF expression pattern of A549 cells under hypoxia. We focused our efforts toward alternative splicing factors, such as Clk1, and pro-angiogenic proliferation-regulating factors, such as Cyr61. We further examined the influence of asTF overexpression on the expression of MCP-1, Cyr61 and VEGF, as well as on cell number and pro-angiogenic properties of A549 cells. Notably, we found hypoxia to induce the expression of alternative splicing factors (Clk1 and Clk4) as well as proliferation- and angiogenesis-promoting factors (Cyr61 and flTF). asTF overexpression in A549 cells also increased both cell number and tube formation. These effects were mediated by the induction of Cyr61, MCP-1 and VEGF, as well as by integrin α(v)β(3). Taken together, our results suggest that the pro-angiogenic potential of A549 lung cancer cells is modulated under hypoxic conditions via modulation of TF isoform expression which in turn is controlled by alternative splicing.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Alternative Splicing / genetics*
  • Cell Hypoxia*
  • Cell Line, Tumor
  • Cell Proliferation
  • Chemokine CCL2 / biosynthesis
  • Chemokine CCL2 / metabolism
  • Cysteine-Rich Protein 61 / biosynthesis
  • Cysteine-Rich Protein 61 / metabolism
  • Humans
  • Integrin alphaVbeta3 / biosynthesis
  • Integrin alphaVbeta3 / metabolism
  • Lung Neoplasms / metabolism*
  • Neovascularization, Pathologic / metabolism*
  • Protein Isoforms / metabolism
  • Protein-Serine-Threonine Kinases / biosynthesis
  • Protein-Tyrosine Kinases / biosynthesis
  • Thromboplastin / metabolism*
  • Vascular Endothelial Growth Factor A / biosynthesis
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • CCL2 protein, human
  • CCN1 protein, human
  • Chemokine CCL2
  • Cysteine-Rich Protein 61
  • Integrin alphaVbeta3
  • Protein Isoforms
  • VEGFA protein, human
  • Vascular Endothelial Growth Factor A
  • Thromboplastin
  • Clk dual-specificity kinases
  • Protein-Tyrosine Kinases
  • Protein-Serine-Threonine Kinases