Thyroid Transcription Factor 1 Reprograms Angiogenic Activities of Secretome

Sci Rep. 2016 Feb 25;6:19857. doi: 10.1038/srep19857.

Abstract

Through both gain- and loss-of-TTF-1 expression strategies, we show that TTF-1 positively regulates vascular endothelial growth factor (VEGF) and that the VEGF promoter element contains multiple TTF-1-responsive sequences. The major signaling receptor for VEGF, i.e VEGFR2, also appears to be under a direct and positive regulation of TTF-1. The TTF-1-dependent upregulation of VEGF was moderately sensitive to rapamycin, implicating a partial involvement of mammalian target of rapamycin (mTOR). However, hypoxia did not further increase the secreted VEGF level of the TTF-1(+) lung cancer cells. The TTF-1-induced VEGF upregulation occurs in both compartments (exosomes and exosome-depleted media (EDM)) of the conditioned media. Surprisingly, the EDM of TTF-1(+) lung cancer cells (designated EDM-TTF-1(+)) displayed an anti-angiogenic activity in the endothelial cell tube formation assay. Mechanistic studies suggest that the increased granulocyte-macrophage colony-stimulating factor (GM-CSF) level in the EDM-TTF-1(+) conferred the antiangiogenic activities. In human lung cancer, the expression of TTF-1 and GM-CSF exhibits a statistically significant and positive correlation. In summary, this study provides evidence that TTF-1 may reprogram lung cancer secreted proteome into an antiangiogenic state, offering a novel basis to account for the long-standing observation of favorable prognosis associated with TTF-1(+) lung adenocarcinomas.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • A549 Cells
  • Angiogenic Proteins / genetics
  • Angiogenic Proteins / metabolism
  • Antibodies / pharmacology
  • Blotting, Western
  • Cell Hypoxia
  • Cell Line, Tumor
  • Cell Survival
  • Culture Media, Conditioned / pharmacology
  • Cytokines / genetics
  • Cytokines / metabolism
  • Enzyme-Linked Immunosorbent Assay
  • Exosomes / metabolism
  • Granulocyte-Macrophage Colony-Stimulating Factor / immunology
  • Granulocyte-Macrophage Colony-Stimulating Factor / pharmacology
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Indoles / toxicity
  • Lung Neoplasms / blood supply
  • Lung Neoplasms / metabolism
  • Lung Neoplasms / pathology
  • Neovascularization, Physiologic / drug effects
  • Nuclear Proteins / antagonists & inhibitors
  • Nuclear Proteins / metabolism*
  • Promoter Regions, Genetic
  • Pyrroles / toxicity
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Real-Time Polymerase Chain Reaction
  • TOR Serine-Threonine Kinases / metabolism
  • Thyroid Nuclear Factor 1
  • Transcription Factors / antagonists & inhibitors
  • Transcription Factors / metabolism*
  • Up-Regulation / drug effects
  • Vascular Endothelial Growth Factor A / analysis
  • Vascular Endothelial Growth Factor A / genetics
  • Vascular Endothelial Growth Factor A / metabolism
  • Vascular Endothelial Growth Factor Receptor-1 / metabolism
  • Vascular Endothelial Growth Factor Receptor-2 / antagonists & inhibitors
  • Vascular Endothelial Growth Factor Receptor-2 / immunology
  • Vascular Endothelial Growth Factor Receptor-2 / metabolism

Substances

  • Angiogenic Proteins
  • Antibodies
  • Culture Media, Conditioned
  • Cytokines
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Indoles
  • NKX2-1 protein, human
  • Nuclear Proteins
  • Pyrroles
  • RNA, Small Interfering
  • Thyroid Nuclear Factor 1
  • Transcription Factors
  • Vascular Endothelial Growth Factor A
  • Semaxinib
  • Granulocyte-Macrophage Colony-Stimulating Factor
  • TOR Serine-Threonine Kinases
  • Vascular Endothelial Growth Factor Receptor-1
  • Vascular Endothelial Growth Factor Receptor-2