Energy metabolism during anchorage-independence. Induction by osteopontin-c

PLoS One. 2014 Aug 26;9(8):e105675. doi: 10.1371/journal.pone.0105675. eCollection 2014.

Abstract

The detachment of epithelial cells, but not cancer cells, causes anoikis due to reduced energy production. Invasive tumor cells generate three splice variants of the metastasis gene osteopontin, the shortest of which (osteopontin-c) supports anchorage-independence. Osteopontin-c signaling upregulates three interdependent pathways of the energy metabolism. Glutathione, glutamine and glutamate support the hexose monophosphate shunt and glycolysis and can feed into the tricarboxylic acid cycle, leading to mitochondrial ATP production. Activation of the glycerol phosphate shuttle also supports the mitochondrial respiratory chain. Drawing substrates from glutamine and glycolysis, the elevated creatine may be synthesized from serine via glycine and supports the energy metabolism by increasing the formation of ATP. Metabolic probing with N-acetyl-L-cysteine, L-glutamate, or glycerol identified differential regulation of the pathway components, with mitochondrial activity being redox dependent and the creatine pathway depending on glutamine. The multiple skewed components in the cellular metabolism synergize in a flow toward two mechanisms of ATP generation, via creatine and the respiratory chain. It is consistent with a stimulation of the energy metabolism that supports anti-anoikis. Our findings imply a coalescence in cancer cells between osteopontin-a, which increases the cellular glucose levels, and osteopontin-c, which utilizes this glucose to generate energy.

Publication types

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

MeSH terms

  • Adenosine Triphosphate / metabolism
  • Amino Acid Sequence
  • Breast / metabolism
  • Breast / pathology*
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Breast Neoplasms / pathology
  • Energy Metabolism*
  • Female
  • Gene Expression Regulation, Neoplastic
  • Glutamine / metabolism
  • Glycerol / metabolism
  • Glycolysis
  • Humans
  • MCF-7 Cells
  • Molecular Sequence Data
  • Mutation
  • Neoplasm Invasiveness / genetics
  • Neoplasm Invasiveness / pathology
  • Osteopontin / chemistry
  • Osteopontin / genetics
  • Osteopontin / metabolism*
  • Oxidation-Reduction
  • Oxidoreductases / genetics
  • Peroxides / metabolism
  • Protein Isoforms / chemistry
  • Protein Isoforms / genetics
  • Protein Isoforms / metabolism
  • Signal Transduction

Substances

  • Peroxides
  • Protein Isoforms
  • Glutamine
  • Osteopontin
  • Adenosine Triphosphate
  • Oxidoreductases
  • Glycerol

Associated data

  • GEO/GSE55193