HSulf-1 deficiency dictates a metabolic reprograming of glycolysis and TCA cycle in ovarian cancer
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Susmita Mondal1, Debarshi Roy1, Juliana Camacho-Pereira2,7, Ashwani Khurana1, Eduardo Chini2, Lifeng Yang3, Joelle Baddour3, Katherine Stilles3, Seth Padmabandu3 , Sam Leung4, Steve Kalloger4 , Blake Gilks4, Val Lowe5, Thomas Dierks6, Edward Hammond8, Keith Dredge8, Deepak Nagrath3 and Viji Shridhar1
1 Department of Experimental Pathology, Mayo Clinic College of Medicine, Rochester, MN, USA
2 Department of Anesthesiology, Mayo Clinic College of Medicine, Rochester, MN, USA
3 Department of Chemical and Biomolecular Engineering, Rice University, Houston, TX, USA
4 Department of Pathology and Laboratory Medicine, University of British Columbia, Canada
5 Department of Nuclear Medicine, Mayo Clinic College of Medicine, Rochester, MN, USA
6 Department of Chemistry, Biochemistry I, Bielefeld University, Bielefeld, Germany
7 Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, RJ, Brazil
8 Progen Pharmaceuticals Ltd, Brisbane, Queensland, Australia
Viji Shridhar, email:
Keywords: HSulf-1, Warburg effect, HB-EGF, ovarian cancer, c-Myc, PG545
Received: May 05, 2015 Accepted: August 27, 2015 Published: September 10, 2015
Warburg effect has emerged as a potential hallmark of many cancers. However, the molecular mechanisms that led to this metabolic state of aerobic glycolysis, particularly in ovarian cancer (OVCA) have not been completely elucidated. HSulf-1 predominantly functions by limiting the bioavailability of heparan binding growth factors and hence their downstream signaling. Here we report that HSulf-1, a known putative tumor suppressor, is a negative regulator of glycolysis. Silencing of HSulf-1 expression in OV202 cell line increased glucose uptake and lactate production by upregulating glycolytic genes such as Glut1, HKII, LDHA, as well as metabolites. Conversely, HSulf-1 overexpression in TOV21G cells resulted in the down regulation of glycolytic enzymes and reduced glycolytic phenotype, supporting the role of HSulf-1 loss in enhanced aerobic glycolysis. HSulf-1 deficiency mediated glycolytic enhancement also resulted in increased inhibitory phosphorylation of pyruvate dehydrogenase (PDH) thus blocking the entry of glucose flux into TCA cycle. Consistent with this, metabolomic and isotope tracer analysis showed reduced glucose flux into TCA cycle. Moreover, HSulf-1 loss is associated with lower oxygen consumption rate (OCR) and impaired mitochondrial function. Mechanistically, lack of HSulf-1 promotes c-Myc induction through HB-EGF-mediated p-ERK activation. Pharmacological inhibition of c-Myc reduced HB-EGF induced glycolytic enzymes implicating a major role of c-Myc in loss of HSulf-1 mediated altered glycolytic pathway in OVCA. Similarly, PG545 treatment, an agent that binds to heparan binding growth factors and sequesters growth factors away from their ligand also blocked HB-EGF signaling and reduced glucose uptake in vivo in HSulf-1 deficient cells.
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