Genomic deletion of malic enzyme 2 confers collateral lethality in pancreatic cancer

Prasenjit Dey, Joelle Baddour, Florian Muller, Chia Chin Wu, Huamin Wang, Wen Ting Liao, Zangdao Lan, Alina Chen, Tony Gutschner, Yaan Kang, Jason Fleming, Nikunj Satani, Di Zhao, Abhinav Achreja, Lifeng Yang, Jiyoon Lee, Edward Chang, Giannicola Genovese, Andrea Viale, Haoqiang YingGiulio Draetta, Anirban Maitra, Y. Alan Wang, Deepak Nagrath, Ronald A. Depinho

Research output: Contribution to journalArticlepeer-review

111 Scopus citations

Abstract

The genome of pancreatic ductal adenocarcinoma (PDAC) frequently contains deletions of tumour suppressor gene loci, most notably SMAD4, which is homozygously deleted in nearly one-third of cases. As loss of neighbouring housekeeping genes can confer collateral lethality, we sought to determine whether loss of the metabolic gene malic enzyme 2 (ME2) in the SMAD4 locus would create cancer-specific metabolic vulnerability upon targeting of its paralogous isoform ME3. The mitochondrial malic enzymes (ME2 and ME3) are oxidative decarboxylases that catalyse the conversion of malate to pyruvate and are essential for NADPH regeneration and reactive oxygen species homeostasis. Here we show that ME3 depletion selectively kills ME2-null PDAC cells in a manner consistent with an essential function for ME3 in ME2-null cancer cells. Mechanistically, integrated metabolomic and molecular investigation of cells deficient in mitochondrial malic enzymes revealed diminished NADPH production and consequent high levels of reactive oxygen species. These changes activate AMP activated protein kinase (AMPK), which in turn directly suppresses sterol regulatory element-binding protein 1 (SREBP1)-directed transcription of its direct targets including the BCAT2 branched-chain amino acid transaminase 2) gene. BCAT2 catalyses the transfer of the amino group from branched-chain amino acids to α-ketoglutarate (α-KG) thereby regenerating glutamate, which functions in part to support de novo nucleotide synthesis. Thus, mitochondrial malic enzyme deficiency, which results in impaired NADPH production, provides a prime 'collateral lethality' therapeutic strategy for the treatment of a substantial fraction of patients diagnosed with this intractable disease.

Original languageEnglish (US)
Pages (from-to)119-123
Number of pages5
JournalNature
Volume542
Issue number7639
DOIs
StatePublished - Feb 2 2017

ASJC Scopus subject areas

  • General Medicine
  • General

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