Phosphoethanolamine Accumulation Protects Cancer Cells under Glutamine Starvation through Downregulation of PCYT2

Cell Rep. 2019 Oct 1;29(1):89-103.e7. doi: 10.1016/j.celrep.2019.08.087.

Abstract

Tolerance to severe tumor microenvironments, including hypoxia and nutrient starvation, is a common feature of aggressive cancer cells and can be targeted. However, metabolic alterations that support cancer cells upon nutrient starvation are not well understood. Here, by comprehensive metabolome analyses, we show that glutamine deprivation leads to phosphoethanolamine (PEtn) accumulation in cancer cells via the downregulation of PEtn cytidylyltransferase (PCYT2), a rate-limiting enzyme of phosphatidylethanolamine biosynthesis. PEtn accumulation correlated with tumor growth under nutrient starvation. PCYT2 suppression was partially mediated by downregulation of the transcription factor ELF3. Furthermore, PCYT2 overexpression reduced PEtn levels and tumor growth. In addition, PEtn accumulation and PCYT2 downregulation in human breast tumors correlated with poor prognosis. Thus, we show that glutamine deprivation leads to tumor progression by regulating PE biosynthesis via the ELF3-PCYT2 axis. Furthermore, manipulating glutamine-responsive genes could be a therapeutic approach to limit cancer progression.

Keywords: PCYT2; PE biosynthesis; amino acids; cancer metabolism; glutamine deprivation; hypoxia; nutrient starvation; phosphoethanolamine; tumor microenvironments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Line, Tumor
  • Disease Progression
  • Down-Regulation / genetics*
  • Ethanolamines / metabolism*
  • Glutamine / metabolism*
  • HeLa Cells
  • Hep G2 Cells
  • Human Umbilical Vein Endothelial Cells
  • Humans
  • MCF-7 Cells
  • Mice, Inbred C57BL
  • Proto-Oncogene Proteins c-ets / genetics
  • RNA Nucleotidyltransferases / genetics*
  • Starvation / metabolism*
  • Transcription, Genetic / genetics

Substances

  • Ethanolamines
  • Proto-Oncogene Proteins c-ets
  • Glutamine
  • phosphorylethanolamine
  • RNA Nucleotidyltransferases
  • Ethanolamine-phosphate cytidylyltransferase