Nicotinamide nucleotide transhydrogenase (NNT) deficiency dysregulates mitochondrial retrograde signaling and impedes proliferation

Hung Yao Ho*, Yu Ting Lin, Gigin Lin, Pei Ru Wu, Mei Ling Cheng

*Corresponding author for this work

Research output: Contribution to journalJournal Article peer-review

53 Scopus citations

Abstract

To study the physiological roles of NADH and NADPH homeostasis in cancer, we studied the effect of NNT knockdown on physiology of SK-Hep1 cells. NNT knockdown cells show limited abilities to maintain NAD+ and NADPH levels and have reduced proliferation and tumorigenicity. There is an increased dependence of energy production on oxidative phosphorylation. Studies with stable isotope tracers have revealed that under the new steady-state metabolic condition, the fluxes of TCA and glycolysis decrease while that of reductive carboxylation increases. Increased [α-ketoglutarate]/[succinate] ratio in NNT-deficient cells results in decrease in HIF-1α level and expression of HIF-1α regulated genes. Reduction in NADPH level leads to repression of HDAC1 activity and an increase in p53 acetylation. These findings suggest that NNT is essential to homeostasis of NADH and NADPH pools, anomalies of which affect HIF-1α- and HDAC1-dependent pathways, and hence retrograde response of mitochondria.

Original languageEnglish
Pages (from-to)916-928
Number of pages13
JournalRedox Biology
Volume12
DOIs
StatePublished - 01 08 2017

Bibliographical note

Publisher Copyright:
© 2017 The Authors

Keywords

  • HDAC1
  • HIF-1α
  • Metabolomics
  • Mitochondria
  • Transhydrogenase

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