Mitochondrial control by DRP1 in brain tumor initiating cells

Nat Neurosci. 2015 Apr;18(4):501-10. doi: 10.1038/nn.3960. Epub 2015 Mar 2.

Abstract

Brain tumor initiating cells (BTICs) co-opt the neuronal high affinity glucose transporter, GLUT3, to withstand metabolic stress. We investigated another mechanism critical to brain metabolism, mitochondrial morphology, in BTICs. BTIC mitochondria were fragmented relative to non-BTIC tumor cell mitochondria, suggesting that BTICs increase mitochondrial fission. The essential mediator of mitochondrial fission, dynamin-related protein 1 (DRP1), showed activating phosphorylation in BTICs and inhibitory phosphorylation in non-BTIC tumor cells. Targeting DRP1 using RNA interference or pharmacologic inhibition induced BTIC apoptosis and inhibited tumor growth. Downstream, DRP1 activity regulated the essential metabolic stress sensor, AMP-activated protein kinase (AMPK), and targeting AMPK rescued the effects of DRP1 disruption. Cyclin-dependent kinase 5 (CDK5) phosphorylated DRP1 to increase its activity in BTICs, whereas Ca(2+)-calmodulin-dependent protein kinase 2 (CAMK2) inhibited DRP1 in non-BTIC tumor cells, suggesting that tumor cell differentiation induces a regulatory switch in mitochondrial morphology. DRP1 activation correlated with poor prognosis in glioblastoma, suggesting that mitochondrial dynamics may represent a therapeutic target for BTICs.

Publication types

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

MeSH terms

  • Apoptosis / drug effects
  • Apoptosis / physiology
  • Brain Neoplasms / metabolism*
  • Cell Line, Tumor
  • GTP Phosphohydrolases / antagonists & inhibitors
  • GTP Phosphohydrolases / metabolism*
  • Glioblastoma / metabolism*
  • Humans
  • Microtubule-Associated Proteins / antagonists & inhibitors
  • Microtubule-Associated Proteins / metabolism*
  • Mitochondria / metabolism*
  • Mitochondria / ultrastructure
  • Mitochondrial Proteins / antagonists & inhibitors
  • Mitochondrial Proteins / metabolism*
  • Neoplastic Stem Cells / drug effects
  • Neoplastic Stem Cells / metabolism*
  • Phosphorylation / drug effects
  • Phosphorylation / physiology
  • Prognosis

Substances

  • Microtubule-Associated Proteins
  • Mitochondrial Proteins
  • GTP Phosphohydrolases
  • DNM1L protein, human