title: Dual-targeting of aberrant glucose metabolism in glioblastoma.
abstract: BACKGROUND
  Glioblastoma (GBM) is the most common and malignant primary brain tumor. In contrast to some other tumor types, aberrant glucose metabolism is an important component of GBM growth and chemoresistance. Recent studies of human orthotopic GBM in mice and in situ demonstrated GBM cells rely on both glycolysis and mitochondrial oxidation for glucose catabolism. These observations suggest that the homeostasis of energy metabolism of GBM cells might be further disturbed by dual-inhibition of glucose metabolism. The present study aimed to evaluate the efficacy and the mechanisms of dual-targeting therapy in GBM cells.
  
  
  METHODS
  Representative GBM cells (immortalized GBM cell lines and patient-derived GBM cells) and non-cancerous cells were treated with 4-(N-(S-penicillaminylacetyl)amino) phenylarsonous acid (PENAO), an in-house designed novel arsenic-based mitochondrial toxin, in combination with dichloroacetate (DCA), a pyruvate dehydrogenase kinase inhibitor. The efficacy of this combinatorial therapy was evaluated by MTS assay, clonogenic surviving assay and apoptotic assays. The underlying mechanisms of this dual-targeting treatment were unraveled by using mitochondrial membrane potential measurements, cytosol/mitochondrial ROS detection, western blotting, extracellular flux assay and mass spectrometry.
  
  
  RESULTS
  As monotherapies, both PENAO and DCA induced proliferation arrest in a panel of GBM cell lines and primary isolates. PENAO inhibited oxygen consumption, induced oxidative stress and depolarized mitochondrial membrane potential, which in turn activated mitochondria-mediated apoptosis. By combining DCA with PENAO, the two drugs worked synergistically to inhibit cell proliferation (but had no significant effect on non-cancerous cells), impair the clonogenicity, and induce mitochondria-mediated apoptosis. An oxidative stress of mitochondrial origin takes a prominent place in the mechanism by which the combination of PENAO and DCA induces cell death. Additionally, PENAO-induced oxidative damage was enhanced by DCA through glycolytic inhibition which in turn diminished acid production induced by PENAO. Moreover, DCA treatment also led to an alteration in the multidrug resistance (MDR) phenotype of GBM cells, thereby leading to an increased cytosolic accumulation of PENAO.
  
  
  CONCLUSIONS
  The findings of this study shed a new light with respect to the dual-targeting of glucose metabolism in GBM cells and the innovative combination of PENAO and DCA shows promise in expanding GBM therapies.
authors: Cure Brain Cancer Neuro-Oncology Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, 2052, Australia. han.shen@unsw.edu.au.
authors: Han
authors: H
authors: Shen
authors: Tumour Metabolism Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, 2052, Australia. s.decollogne@unsw.edu.au.
authors: Stephanie
authors: S
authors: Decollogne
authors: Tumour Metabolism Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, 2052, Australia. p.dilda@unsw.edu.au.
authors: Pierre J
authors: PJ
authors: Dilda
authors: Cure Brain Cancer Neuro-Oncology Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, 2052, Australia. helloerico@yahoo.com.|Cancer Care Centre, St George Hospital, Kogarah, NSW, 2217, Australia. helloerico@yahoo.com.
authors: Eric
authors: E
authors: Hau
authors: Cure Brain Cancer Neuro-Oncology Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, 2052, Australia. sylvia.chung@student.unsw.edu.au.
authors: Sylvia A
authors: SA
authors: Chung
authors: Tumour Metabolism Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, 2052, Australia. peter.luk@unswalumni.com.
authors: Peter P
authors: PP
authors: Luk
authors: Tumour Metabolism Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, NSW, 2052, Australia. p.hogg@unsw.edu.au.
authors: Philip J
authors: PJ
authors: Hogg
authors: Cure Brain Cancer Neuro-Oncology Group, Adult Cancer Program, Lowy Cancer Research Centre and Prince of Wales Clinical School, University of New South Wales, Sydney, 2052, Australia. k.mcdonald@unsw.edu.au.
authors: Kerrie L
authors: KL
authors: McDonald
mesh_terms: D001152:Arsenicals / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D003999:Dichloroacetic Acid / Q000494:pharmacology; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects; D015870:Gene Expression; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D027425:ATP-Binding Cassette, Sub-Family C Proteins / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D001152:Arsenicals; D003999:Dichloroacetic Acid; D005947:Glucose; D027425:ATP-Binding Cassette, Sub-Family C Proteins; D017382:Reactive Oxygen Species; C046652:phenylarsonous acid; C421109:multidrug resistance-associated protein 1
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