title: Involvement of the nitric oxide/protein kinase G pathway in polychlorinated biphenyl-induced cell death in SH-SY 5Y neuroblastoma cells.
abstract: Polychlorinated biphenyls (PCB) are persistent environmental contaminants whose chronic exposure can affect nervous system development and function. The cellular and molecular mechanisms underlying neuronal damage are not yet clear. In the present study, we investigated whether nitric oxide (NO) could be involved in aroclor 1254 (A1254; a PCB mixture)-induced cytotoxicity in SH-SY5Y human neuroblastoma cells. Prolonged exposure (24 hr) to A1254 (10-100 microg/ml) caused a dose-dependent reduction of cell viability that was attenuated in the presence of a calcium entry blocker, gadolinum (Gd(3+)) at 10 microM, a concentration able to block voltage-sensitive calcium channels. In addition, A1254 caused an increase of cytosolic calcium that was dependent on extracellular calcium, as measured by fura-2 videomicroscopy. A1254-induced calcium rise may stimulate NO production through an activation of neuronal NOS (nNOS). Indeed, the concomitant addition of the selective nNOS inhibitor N(omega)-propyl-L-arginine (NPLA) and A1254 prevented cell injury, suggesting that NO production plays a major role in A1254-evoked cell injury. Furthermore, the exposure (14 hr) to A1254 (30 microg/ml) produced an up-regulation of the expression of beta isoform of nNOS. This up-regulation was calcium dependent and was accompanied by an enhancement of NO production as demonstrated by an increase of nitrite formation. Moreover, A1254-induced cell injury was prevented when KT 5823, a selective cGMP/PKG inhibitor, was added concomitantly to 30 microg/ml A1254. These results suggest that PCB-induced cell death in neuroblastoma cells is mediated by an activation of the cGMP/PKG pathway triggered by NO production.
authors.affiliation: Department of Biological and Environmental Sciences, University of Sannio, Benevento, Italy.
authors.forename: Lorella M T
authors.initials: LM
authors.lastname: Canzoniero
authors.forename: Annagrazia
authors.initials: A
authors.lastname: Adornetto
authors.forename: Agnese
authors.initials: A
authors.lastname: Secondo
authors.forename: Simona
authors.initials: S
authors.lastname: Magi
authors.forename: Carmela
authors.initials: C
authors.lastname: Dell'aversano
authors.forename: Antonella
authors.initials: A
authors.lastname: Scorziello
authors.forename: Salvatore
authors.initials: S
authors.lastname: Amoroso
authors.forename: Gianfranco
authors.initials: G
authors.lastname: Di Renzo
mesh_terms: D002121:Calcium Channel Blockers / Q000494:pharmacology; D015220:Calcium Channels / Q000187:drug effects / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects / Q000502:physiology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D020111:Chlorodiphenyl (54% Chlorine) / Q000633:toxicity; D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004781:Environmental Exposure / Q000009:adverse effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D009410:Nerve Degeneration / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D009498:Neurotoxins / Q000633:toxicity*; D009569:Nitric Oxide / Q000378:metabolism*; D052248:Nitric Oxide Synthase Type I / Q000187:drug effects / Q000378:metabolism; D018384:Oxidative Stress / Q000187:drug effects / Q000502:physiology; D011078:Polychlorinated Biphenyls / Q000633:toxicity*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D015854:Up-Regulation / Q000187:drug effects / Q000502:physiology
chemical_list: D002121:Calcium Channel Blockers; D015220:Calcium Channels; D004791:Enzyme Inhibitors; D009498:Neurotoxins; D020111:Chlorodiphenyl (54% Chlorine); D009569:Nitric Oxide; D011078:Polychlorinated Biphenyls; D052248:Nitric Oxide Synthase Type I; D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP