title: A HERG current sustains a cardiac-type action potential in neuroblastoma S cells.
abstract: From the adrenergic SH-SY5Y human neuroblastoma clone, we isolated a subclone (21S) endowed with a glial-oriented phenotype. At difference from the parental clone, 21S cells responded to depolarizing stimuli with overshooting action potentials, whose repolarization phase was composed of an initial rapid episode, followed by a long-lasting plateau and a slow return to the resting potential (V(REST)). The action potential depolarization phase was sustained by a TTX-sensitive Na(+) current, while the first repolarizing episode was produced by the scanty delayed rectifier potassium current (I(KDR)) expressed in 21S cells. The bulk of repolarization, including the after-hyperpolarization, was sustained by the human eag related (HERG) potassium current (I(HERG)) that also governs V(REST) in 21S cells. This double role of I(HERG), together with the poor expression of I(KDRs), represents a novel finding in electrophysiology, as well as gives a clue to identify a new excitable element of the complex cellular population of neuroblastoma.
authors.affiliation: Department of Experimental Pathology and Oncology, University of Florence, Viale Morgagni 50, Florence 50134, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: D'Amico
authors.forename: Tiziana
authors.initials: T
authors.lastname: Biagiotti
authors.forename: Lucrezia
authors.initials: L
authors.lastname: Fontana
authors.forename: Rita
authors.initials: R
authors.lastname: Restano-Cassulini
authors.forename: Nadia
authors.initials: N
authors.lastname: Lasagna
authors.forename: Annarosa
authors.initials: A
authors.lastname: Arcangeli
authors.forename: Enzo
authors.initials: E
authors.lastname: Wanke
authors.forename: Massimo
authors.initials: M
authors.lastname: Olivotto
mesh_terms: D015153:Blotting, Western; D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; D005455:Fluorescent Antibody Technique; D006321:Heart / Q000502:physiology*; D006801:Humans; D009447:Neuroblastoma / Q000473:pathology / Q000503:physiopathology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000502:physiology*; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG; D014407:Tumor Cells, Cultured
chemical_list: D027682:Cation Transport Proteins; D004268:DNA-Binding Proteins; C072312:ERG protein, human; D000072237:ERG1 Potassium Channel; D051638:Ether-A-Go-Go Potassium Channels; C000606913:KCNH2 protein, human; C092509:KCNH6 protein, human; D015221:Potassium Channels; D024642:Potassium Channels, Voltage-Gated; D015534:Trans-Activators; D000071230:Transcriptional Regulator ERG