Inhibition of Prostaglandin Reductase 2, a Putative Oncogene Overexpressed in Human Pancreatic Adenocarcinoma, Induces Oxidative Stress-Mediated Cell Death Involving xCT and CTH Gene Expressions through 15-Keto-PGE2

PLoS One. 2016 Jan 28;11(1):e0147390. doi: 10.1371/journal.pone.0147390. eCollection 2016.

Abstract

Prostaglandin reductase 2 (PTGR2) is the enzyme that catalyzes 15-keto-PGE2, an endogenous PPARγ ligand, into 13,14-dihydro-15-keto-PGE2. Previously, we have reported a novel oncogenic role of PTGR2 in gastric cancer, where PTGR2 was discovered to modulate ROS-mediated cell death and tumor transformation. In the present study, we demonstrated the oncogenic potency of PTGR2 in pancreatic cancer. First, we observed that the majority of the human pancreatic ductal adenocarcinoma tissues was stained positive for PTGR2 expression but not in the adjacent normal parts. In vitro analyses showed that silencing of PTGR2 expression enhanced ROS production, suppressed pancreatic cell proliferation, and promoted cell death through increasing 15-keto-PGE2. Mechanistically, silencing of PTGR2 or addition of 15-keto-PGE2 suppressed the expressions of solute carrier family 7 member 11 (xCT) and cystathionine gamma-lyase (CTH), two important providers of intracellular cysteine for the generation of glutathione (GSH), which is widely accepted as the first-line antioxidative defense. The oxidative stress-mediated cell death after silencing of PTGR2 or addition of 15-keto-PGE2 was further abolished after restoring intracellular GSH concentrations and cysteine supply by N-acetyl-L-cysteine and 2-Mercaptomethanol. Our data highlight the therapeutic potential of targeting PTGR2/15-keto-PGE2 for pancreatic cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 15-Oxoprostaglandin 13-Reductase
  • Alcohol Dehydrogenase / genetics*
  • Alcohol Dehydrogenase / metabolism
  • Amino Acid Transport System y+ / genetics
  • Amino Acid Transport System y+ / metabolism
  • Apoptosis
  • Carcinoma, Pancreatic Ductal / enzymology*
  • Cell Line, Tumor
  • Cell Proliferation
  • Cell Survival
  • Cystathionine gamma-Lyase / genetics
  • Cystathionine gamma-Lyase / metabolism
  • Dinoprostone / analogs & derivatives*
  • Dinoprostone / physiology
  • Gene Expression
  • Gene Expression Regulation, Neoplastic
  • Gene Knockdown Techniques
  • Glutathione / metabolism
  • Humans
  • Oxidative Stress*
  • PPAR gamma / metabolism
  • Pancreatic Neoplasms / enzymology*
  • Reactive Oxygen Species / metabolism

Substances

  • Amino Acid Transport System y+
  • PPAR gamma
  • Reactive Oxygen Species
  • SLC7A11 protein, human
  • 15-ketoprostaglandin E2
  • Alcohol Dehydrogenase
  • 15-Oxoprostaglandin 13-Reductase
  • PTGR2 protein, human
  • Cystathionine gamma-Lyase
  • Glutathione
  • Dinoprostone

Grants and funding

This work was done with a grant (NSC 100-2314-B-002 -068 -MY3) from the National Science Council of Taiwan (https://www.most.gov.tw/), and it did not require any external funding. LMC received the funding. The funder had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.