Effect of hypoxia on tissue factor pathway inhibitor expression in breast cancer

J Thromb Haemost. 2016 Feb;14(2):387-96. doi: 10.1111/jth.13206. Epub 2016 Jan 30.


ESSENTIALS: A hypoxic microenvironment is a common feature of tumors that may influence activation of coagulation. MCF-7 and SK-BR-3 breast cancer cells and breast cancer tissue samples were used. The results showed transcriptional repression of tissue factor pathway inhibitor expression in hypoxia. Hypoxia-inducible factor 1α may be a target for the therapy of cancer-related coagulation and thrombosis.

Background: Activation of coagulation is a common finding in patients with cancer, and is associated with an increased risk of venous thrombosis. As a hypoxic microenvironment is a common feature of solid tumors, we investigated the role of hypoxia in the regulation of tissue factor (TF) pathway inhibitor (TFPI) expression in breast cancer.

Objectives: To explore the transcriptional regulation of TFPI by hypoxia-inducible factor (HIF)-1α in breast cancer cells and their correlation in breast cancer tissues.

Methods and results: MCF-7 and SK-BR-3 breast cancer cells were cultured in 1% oxygen or treated with cobalt chloride (CoCl2 ) to mimic hypoxia. Time-dependent and dose-dependent downregulation of TFPI mRNA (quantitative RT-PCR) and of free TFPI protein (ELISA) were observed in hypoxia. Western blotting showed parallel increases in the levels of HIF-1α protein and TF. HIF-1α inhibitor abolished or attenuated the hypoxia-induced downregulation of TFPI. Luciferase reporter assay showed that both hypoxia and HIF-1α overexpression caused strong repression of TFPI promoter activity. Subsequent chromatin immunoprecipitation and mutagenesis analysis demonstrated a functional hypoxia response element within the TFPI promoter, located at -1065 to -1060 relative to the transcriptional start point. In breast cancer tissue samples, gene expression analyses showed a positive correlation between the mRNA expression of TFPI and that of HIF-1α.

Conclusions: This study demonstrates that HIF-1α is involved in the transcriptional regulation of the TFPI gene, and suggests that a hypoxic microenvironment inside a breast tumor may induce a procoagulant state in breast cancer patients.

Keywords: HIF-1α protein; blood coagulation; breast cancer; human; hypoxia; tissue factor pathway inhibitor.

MeSH terms

  • Adult
  • Aged
  • Binding Sites
  • Blood Coagulation*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Cell Hypoxia
  • Down-Regulation
  • Female
  • Gene Expression Regulation, Neoplastic
  • HEK293 Cells
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Lipoproteins / genetics
  • Lipoproteins / metabolism*
  • MCF-7 Cells
  • Middle Aged
  • Oxygen / metabolism*
  • Promoter Regions, Genetic
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Time Factors
  • Transcription, Genetic
  • Transfection
  • Tumor Microenvironment


  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Lipoproteins
  • RNA, Messenger
  • lipoprotein-associated coagulation inhibitor
  • Oxygen