title: Cancer Stem Cells are Depolarized Relative to Normal Stem Cells Derived from Human Livers.
abstract: The inability to distinguish cancer (CSCs) from normal stem cells (NSCs) has hindered attempts to identify safer, more effective therapies for hepatocellular carcinoma (HCC). The aim of this study was to document and compare cell membrane potential differences (PDs) of CSCs and NSCs derived from human HCC and healthy livers respectively and determine whether altered GABAergic innervation could explain the differences.
  
  
  
  Epithelial cell adhesion molecule (EpCAM) positive stem cells were isolated from human liver tissues by magnetic bead separations. Cellular PDs were recorded by microelectrode impalement of freshly isolated cells. GABAA receptor subunit expression was documented by reverse transcriptase polymerase chain reaction (RT-PCR) and immunofluorescence.
  
  
  
  CSCs were significantly depolarized (-7.0 ± 1.3 mV) relative to NSCs (-23.0 ± 1.4 mV, p &amp;lt; 0.01). The depolarized state was associated with different GABAA receptor subunit expression profiles wherein phasic transmission, represented by GAGAA α3 subunit expression, was prevalent in CSCs while tonic transmission, represented by GABAA α6 subunit expression, prevailed in NSCs. In addition, GABAA subunits α3, β3, ϒ3 and δ were strongly expressed in CSCs while GABAA π expression was dominant in NSCs. CSCs and NSCs responded similarly to GABAA receptor agonists (ΔPD: 12.5 ± 1.2 mV and 11.0 ± 3.5 mV respectively).
  
  
  
  The results of this study indicate that CSCs are significantly depolarized relative to NSCs and these differences are associated with differences in GABAA receptor subunit expression. Together they provide new insights into the pathogenesis and possible treatment of human HCC.
authors.affiliation: Section of Hepatology, Department of Medicine.
authors.forename: Wendy
authors.initials: W
authors.lastname: Bautista
authors.affiliation: Department of Surgery, ***Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Jeremy
authors.initials: J
authors.lastname: Lipschitz
authors.affiliation: Department of Surgery, ***Department of Pharmacology and Therapeutics, University of Manitoba, Winnipeg, Manitoba, Canada.
authors.forename: Andrew
authors.initials: A
authors.lastname: McKay
authors.affiliation: Section of Hepatology, Department of Medicine.
authors.forename: Gerald Y
authors.initials: GY
authors.lastname: Minuk
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D000071858:Epithelial Cell Adhesion Molecule / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D058785:GABA-A Receptor Agonists / Q000494:pharmacology; D006801:Humans; D018189:Immunomagnetic Separation; D008099:Liver / Q000166:cytology*; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects; D014411:Neoplastic Stem Cells / Q000187:drug effects / Q000378:metabolism*; D010641:Phenotype; D021122:Protein Subunits; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011963:Receptors, GABA-A / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*
chemical_list: D015415:Biomarkers; C499379:EPCAM protein, human; D000071858:Epithelial Cell Adhesion Molecule; D058785:GABA-A Receptor Agonists; D021122:Protein Subunits; D012333:RNA, Messenger; D011963:Receptors, GABA-A
keywords: Cancer Stem Cell; GABA; Liver; Normal stem cell; Stem Cells; hepatocellular carcinoma; membrane potential