title: Therapeutic concentrations of valproate but not amitriptyline increase neuropeptide Y (NPY) expression in the human SH-SY5Y neuroblastoma cell line.
abstract: Neuropeptide Y (NPY) is a peptide found in the brain and autonomic nervous system, which is associated with anxiety, depression, epilepsy, learning and memory, sleep, obesity and circadian rhythms. NPY has recently gained much attention as an endogenous antiepileptic and antidepressant agent, as drugs with antiepileptic and/or mood-stabilizing properties may exert their action by increasing NPY concentrations, which in turn can reduce anxiety and depression levels, dampen seizures or increase seizure threshold. We have used human neuroblastoma SH-SY5Y cells to investigate the effect of valproate (VPA) and amitriptyline (AMI) on NPY expression at therapeutic plasma concentrations of 0.6mM and 630nM, respectively. In addition, 12-O-tetradecanoylphorbol-13-acetate (TPA) known to differentiate SH-SY5Y cells into a neuronal phenotype and to increase NPY expression through activation of protein kinase C (PKC) was applied as a positive control (16nM). Cell viability after drug treatment was tested with a 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. NPY expression was measured using immunofluorescence and quantitative RT-PCR (qRT-PCR). Results from immunocytochemistry have shown NPY levels to be significantly increased following a 72h but not 24h VPA treatment. A further increase in expression was observed with simultaneous VPA and TPA treatment, suggesting that the two agents may increase NPY expression through different mechanisms. The increase in NPY mRNA by VPA and TPA was confirmed with qRT-PCR after 72h. In contrast, AMI had no effect on NPY expression in SH-SY5Y cells. Together, the data point to an elevation of human NPY mRNA and peptide levels by therapeutic concentrations of VPA following chronic treatment. Thus, upregulation of NPY may have an impact in anti-cancer treatment of neuroblastomas with VPA, and antagonizing hypothalamic NPY effects may help to ameliorate VPA-induced weight gain and obesity without interfering with the desired central effects of VPA.
authors.affiliation: Department of Anatomy and Neuroscience, University College Cork, Cork, Ireland.
authors.forename: Lorna A
authors.initials: LA
authors.lastname: Farrelly
authors.forename: Niall T P
authors.initials: NT
authors.lastname: Savage
authors.forename: Cristina
authors.initials: C
authors.lastname: O'Callaghan
authors.forename: André
authors.initials: A
authors.lastname: Toulouse
authors.forename: Deniz M
authors.initials: DM
authors.lastname: Yilmazer-Hanke
mesh_terms: D000639:Amitriptyline / Q000494:pharmacology*; D000927:Anticonvulsants / Q000494:pharmacology*; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects; D015870:Gene Expression / Q000187:drug effects*; D006801:Humans; D009447:Neuroblastoma; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014635:Valproic Acid / Q000494:pharmacology*
chemical_list: D000927:Anticonvulsants; D009478:Neuropeptide Y; D000639:Amitriptyline; D014635:Valproic Acid; D013755:Tetradecanoylphorbol Acetate
keywords: 12-O-tetradecanoylphorbol-13-acetate; 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; AMI; AP-1; Atoh1; BDNF; Bone metabolism; CREB; Cancer; Cp; DMEM/F12 Ham; Depression; Dulbecco's Modified Eagle's Medium F12 Ham; ERK; Epilepsy; FCS; GSK3; HBSS; HDAC; Hanks balanced salt solution; MAPK; MTT; NA; NADPH diaphorase; NADPHd; NOS; NPY; Neuropeptide Y; Ngn1; Obesity; PBS; PI3K; PIMT; PKC; PP; PYY; RT; SDHA; SSRI; TPA; VPA; activator protein 1; amitriptyline; atonal homolog-1; base pair; bp; brain-derived neurotrophic factor; cAMP response element-binding protein; crossing point; extracellular signal-regulated kinase; fetal calf serum; glycogen synthase kinase-3; histone deacetylase; mitogen-activated protein kinase; neurogenin-1; neuropeptide Y; nitric oxide synthase; noradrenalin; pancreatic polypeptide; phosphate buffered saline; phosphatidylinositide 3-kinase; polypeptide YY; protein kinase C; protein l-isoaspartyl methyltransferase; qRT-PCR; quantitative reverse transcription polymerase chain reaction; reverse transcription; selective serotonin reuptake inhibitor; sodium valproate; succinate dehydrogenase complex, subunit A, flavoprotein; trk; tropomyosin-receptor kinase