Inhibition of hypoxic response decreases stemness and reduces tumorigenic signaling due to impaired assembly of HIF1 transcription complex in pancreatic cancer

Sci Rep. 2017 Aug 11;7(1):7872. doi: 10.1038/s41598-017-08447-3.


Pancreatic tumors are renowned for their extremely hypoxic centers, resulting in upregulation of a number of hypoxia mediated signaling pathways including cell proliferation, metabolism and cell survival. Previous studies from our laboratory have shown that Minnelide, a water-soluble pro-drug of triptolide (anti-cancer compound), decreases viability of cancer cells in vitro as well as in vivo. However, its mechanism of action remain elusive. In the current study we evaluated the effect of Minnelide, on hypoxia mediated oncogenic signaling as well as stemness in pancreatic cancer. Minnelide has just completed Phase 1 trial against GI cancers and is currently awaiting Phase 2 trials. Our results showed that upon treatment with triptolide, HIF-1α protein accumulated in pancreatic cancer cells even though hypoxic response was decreased in them. Our studies showed even though HIF-1α is accumulated in the treated cells, there was no decrease in HIF-1 binding to hypoxia response elements. However, the HIF-1 transcriptional activity was significantly reduced owing to depletion of co-activator p300 upon treatment with triptolide. Further, treatment with triptolide resulted in a decreased activity of Sp1 and NF-kB the two major oncogenic signaling pathway in pancreatic cancer along with a decreased tumor initiating cell (TIC) population in pancreatic tumor.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Carcinogenesis / drug effects*
  • Carcinogenesis / genetics
  • Carcinogenesis / metabolism
  • Cell Hypoxia
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Cell Proliferation / genetics
  • Diterpenes
  • Epoxy Compounds
  • Gene Expression Regulation, Neoplastic / drug effects
  • Humans
  • Hypoxia
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism*
  • Mice, SCID
  • Neoplastic Stem Cells / drug effects*
  • Neoplastic Stem Cells / metabolism
  • Organophosphates / pharmacology*
  • Pancreatic Neoplasms / drug therapy*
  • Pancreatic Neoplasms / genetics
  • Pancreatic Neoplasms / metabolism
  • Phenanthrenes / pharmacology*
  • Signal Transduction / drug effects
  • Signal Transduction / genetics
  • Xenograft Model Antitumor Assays*


  • Diterpenes
  • Epoxy Compounds
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Organophosphates
  • Phenanthrenes
  • 14-O-phosphonooxymethyltriptolide disodium salt