Transforming growth factor-β promotes aggressiveness and invasion of clear cell renal cell carcinoma

Oncotarget. 2016 Jun 14;7(24):35917-35931. doi: 10.18632/oncotarget.9177.

Abstract

The molecular mechanisms whereby transforming growth factor-β (TGF-β) promotes clear cell renal cell carcinoma (ccRCC) progression is elusive. The cell membrane bound TGF-β type I receptor (ALK5), was recently found to undergo proteolytic cleavage in aggressive prostate cancer cells, resulting in liberation and subsequent nuclear translocation of its intracellular domain (ICD), suggesting that ALK5-ICD might be a useful cancer biomarker. Herein, the possible correlation between ALK5 full length (ALK5-FL) and ALK5-ICD protein, phosphorylated Smad2/3 (pSmad2/3), and expression of TGF-β target gene PAI-1, was investigated in a clinical ccRCC material, in relation to tumor grade, stage, size and cancer specific survival. Expression of ALK5-FL, ALK5-ICD, pSmad2/3 and PAI-1 protein levels were significantly higher in higher stage and associated with adverse survival. ALK5-ICD, pSmad2/3 and PAI-1 correlated with higher grade, and ALK5-FL, pSmad2/3 and PAI-1 protein levels were significantly correlated with larger tumor size. Moreover, the functional role of the TGF-β - ALK5-ICD pathway were investigated in two ccRCC cell lines by treatment with ADAM/MMP2 inhibitor TAPI-2, which prevented TGF-β-induced ALK5-ICD generation, nuclear translocation, as well as cell invasion. The present study demonstrated that canonical TGF-β Smad2/3 pathway and generation of ALK5-ICD correlates with poor survival and invasion of ccRCC in vitro.

Keywords: ALK5; PAI-1; TGF-β signaling pathway; ccRCC; pSmad2/3.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Carcinoma, Renal Cell / genetics*
  • Carcinoma, Renal Cell / metabolism
  • Carcinoma, Renal Cell / pathology
  • Cell Line, Tumor
  • Female
  • Gene Expression Regulation, Neoplastic / drug effects*
  • Humans
  • Kaplan-Meier Estimate
  • Kidney Neoplasms / genetics*
  • Kidney Neoplasms / metabolism
  • Kidney Neoplasms / pathology
  • Male
  • Middle Aged
  • Neoplasm Invasiveness
  • Plasminogen Activator Inhibitor 1 / genetics
  • Plasminogen Activator Inhibitor 1 / metabolism
  • Protein Serine-Threonine Kinases / genetics
  • Protein Serine-Threonine Kinases / metabolism
  • Receptor, Transforming Growth Factor-beta Type I
  • Receptors, Transforming Growth Factor beta / genetics
  • Receptors, Transforming Growth Factor beta / metabolism
  • Smad2 Protein / genetics
  • Smad2 Protein / metabolism
  • Smad3 Protein / genetics
  • Smad3 Protein / metabolism
  • Transforming Growth Factor beta / pharmacology*

Substances

  • Plasminogen Activator Inhibitor 1
  • Receptors, Transforming Growth Factor beta
  • SERPINE1 protein, human
  • SMAD2 protein, human
  • SMAD3 protein, human
  • Smad2 Protein
  • Smad3 Protein
  • Transforming Growth Factor beta
  • Protein Serine-Threonine Kinases
  • Receptor, Transforming Growth Factor-beta Type I
  • TGFBR1 protein, human