Upregulation of autophagy by hypoxia-inducible factor-1α promotes EMT and metastatic ability of CD133+ pancreatic cancer stem-like cells during intermittent hypoxia

Oncol Rep. 2014 Sep;32(3):935-42. doi: 10.3892/or.2014.3298. Epub 2014 Jul 2.

Abstract

Epithelial-to-mesenchymal transition (EMT) facilitates the escape of pancreatic cancer cells from the primary tumor site, which is a key early event in metastasis. In the present study, we examined if intermittent hypoxia facilitates the invasiveness of human pancreatic cancer cell lines (Panc-1 and BxPC-3) by Transwell assay. We used western blotting and flow cytometry analysis to quantify stem-like cells in the migratory cells during intermittent hypoxia in the human pancreatic cancer cells. Under normoxia or intermittent hypoxia, the expression of autophagy-related proteins (LC3-II and Beclin), hypoxia-inducible factor-1α (HIF-1α) and EMT-related markers (E-cadherin, Vimentin and N-cadherin) was examined by western blotting. siRNA and the autophagic inhibitor were used to access the role of HIF-1α and autophagy in promoting metastasis and EMT. Under intermittent hypoxia, pancreatic cancer cells demonstrated enhanced invasive ability and enriched stem-like cells. The migratory cells displayed stem-like cell characteristics and elevated the expression of LC3-II and Beclin-1, HIF-1α, E-cadherin, Vimentin and N-cadherin under intermittent hypoxia conditions. Moreover, enhanced autophagy was induced by the elevated level of HIF-1α. The metastatic ability and EMT of pancreatic cancer stem cells was associated with HIF-1α and autophagy. This novel finding may indicate the specific role of HIF-1α and autophagy in promoting the metastatic ability of pancreatic cancer stem cells. Additionally, it emphasizes the importance of developing therapeutic strategies targeting cancer stem cells and autophagy to reduce metastasis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • AC133 Antigen
  • Antigens, CD / metabolism*
  • Autophagy*
  • Cell Hypoxia
  • Cell Line, Tumor
  • Cell Movement
  • Epithelial-Mesenchymal Transition
  • Glycoproteins / metabolism*
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Neoplasm Metastasis
  • Neoplastic Stem Cells / metabolism
  • Neoplastic Stem Cells / pathology*
  • Pancreatic Neoplasms / metabolism
  • Pancreatic Neoplasms / pathology*
  • Peptides / metabolism*
  • Up-Regulation

Substances

  • AC133 Antigen
  • Antigens, CD
  • Glycoproteins
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • PROM1 protein, human
  • Peptides