title: Role of TRPM2 in cell proliferation and susceptibility to oxidative stress.
abstract: The transient receptor potential (TRP) channel TRPM2 is an ion channel that modulates cell survival. We report here that full-length (TRPM2-L) and short (TRPM2-S) isoform expression was significantly increased in human neuroblastoma compared with adrenal gland. To differentiate the roles of TRPM2-L and TRPM2-S in cell proliferation and survival, we established neuroblastoma SH-SY5Y cell lines stably expressing either TRPM2 isoform or empty vector. Cells expressing TRPM2-S showed significantly enhanced proliferation, downregulation of phosphatase and tensin homolog (PTEN), and increased protein kinase B (Akt) phosphorylation and cell surface glucose transporter 1 (Glut1) compared with cells expressing TRPM2-L or empty vector. ERK phosphorylation was increased, and forkhead box O 3a (FOXO3a) levels were decreased. Inhibitor studies demonstrated that enhanced proliferation was dependent on phosphatidylinositol 3-kinase/Akt, ERK, and NADPH oxidase activation. On the other hand, TRPM2-S-expressing cells were significantly more susceptible to cell death induced by low H2O2 concentrations (50-100 μM), whereas TRPM2-L-expressing cells were protected. This was associated with a significant increase in FOXO3a, MnSOD (SOD2), and membrane Glut1 in TRPM2-L-expressing cells compared with TRPM2-S expressing cells. We conclude that TRPM2 channels occupy a key role in cell proliferation and survival following oxidative stress in neuroblastoma. Our results suggest that overexpression of TRPM2-S results in increased proliferation through phosphatidylinositol 3-kinase/Akt and ERK pathways, while overexpression of TRPM2-L confers protection against oxidative stress-induced cell death through FOXO3a and SOD. TRPM2 channels may represent a novel future therapeutic target in diseases involving oxidative stress.
authors.affiliation: Department of Pediatrics, Pennsylvania State University College of Medicine, Milton S. Hershey Medical Center, PO Box 850, Hershey, PA 17033, USA.
authors.forename: Shu-jen
authors.initials: SJ
authors.lastname: Chen
authors.forename: Wenyi
authors.initials: W
authors.lastname: Zhang
authors.forename: Qin
authors.initials: Q
authors.lastname: Tong
authors.forename: Kathleen
authors.initials: K
authors.lastname: Conrad
authors.forename: Iwona
authors.initials: I
authors.lastname: Hirschler-Laszkiewicz
authors.forename: Michael
authors.initials: M
authors.lastname: Bayerl
authors.forename: Jason K
authors.initials: JK
authors.lastname: Kim
authors.forename: Joseph Y
authors.initials: JY
authors.lastname: Cheung
authors.forename: Barbara A
authors.initials: BA
authors.lastname: Miller
mesh_terms: D000311:Adrenal Glands / Q000378:metabolism*; D016923:Cell Death; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival; D015536:Down-Regulation; D004789:Enzyme Activation; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors / Q000096:biosynthesis; D051272:Glucose Transporter Type 1 / Q000096:biosynthesis; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D019255:NADPH Oxidases / Q000378:metabolism; D009447:Neuroblastoma / Q000378:metabolism*; D018384:Oxidative Stress; D051059:PTEN Phosphohydrolase / Q000096:biosynthesis; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D010766:Phosphorylation; D020033:Protein Isoforms / Q000096:biosynthesis; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D013482:Superoxide Dismutase / Q000096:biosynthesis; D050053:TRPM Cation Channels / Q000378:metabolism*; D000099156:Superoxide Dismutase 2
chemical_list: D048049:Extracellular Signal-Regulated MAP Kinases; D000071316:Forkhead Box Protein O3; D051858:Forkhead Transcription Factors; D051272:Glucose Transporter Type 1; D006861:Hydrogen Peroxide; D019255:NADPH Oxidases; D051059:PTEN Phosphohydrolase; D058539:Phosphatidylinositol 3-Kinase; D020033:Protein Isoforms; D051057:Proto-Oncogene Proteins c-akt; D013482:Superoxide Dismutase; D050053:TRPM Cation Channels; D000099156:Superoxide Dismutase 2; C499517:FOXO3 protein, human; C495677:SLC2A1 protein, human; C121934:TRPM2 protein, human; C494929:PTEN protein, human