title: Apoptosis induced by extracellular ATP in the mouse neuroblastoma cell line N1E-115: studies on involvement of P2 receptors and adenosine.
abstract: Adenosine triphosphate (ATP) can be released in large amounts from (damaged) cells, leading to locally high concentrations. In this study, we investigated the effect of such high concentrations of ATP on neuroblastoma cells. ATP (>or=30 microM) induced apoptosis in the mouse neuroblastoma cell line N1E-115. Activation of the ATP receptor P2X(7) is one of the routes via which ATP has been shown to induce apoptosis. Although the P2X(7) receptor was present in N1E-115 cells, both at the protein and mRNA level, studies with the P2X(7) receptor agonist benzoyl-benzoyl ATP showed that this receptor was not involved in ATP-induced apoptosis. It has been shown previously that adenosine induces apoptosis in N1E-115 cells after transport inside the cell. In this study, both dipyridamole, a nucleoside transport protein blocker, and uridine, a substrate for this transporter, were able to block ATP-induced apoptosis. This indicated that ATP had to be broken down to adenosine to induce apoptosis. The ecto-nucleotidase inhibitors 6-N,N-diethyl-beta-dibromomethylene-D-adenosine-5'-triphosphate (ARL67156) and alpha,beta-methylene adenosine 5'-diphosphate (AOPCP) commonly used to slow breakdown of ATP did not inhibit ATP breakdown appreciably, while the ATP antagonist PPADS inhibited the breakdown of AMP to adenosine; PPADS was also the only compound capable of inhibiting ATP-induced apoptosis. We conclude that the main route of ATP-induced apoptosis in N1E-115 cells was via breakdown to adenosine.
authors.affiliation: Department of Toxicology, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
authors.forename: S Mariëtte
authors.initials: SM
authors.lastname: Schrier
authors.forename: Bogdan I
authors.initials: BI
authors.lastname: Florea
authors.forename: Gerard J
authors.initials: GJ
authors.lastname: Mulder
authors.forename: J Fred
authors.initials: JF
authors.lastname: Nagelkerke
authors.forename: Ad P
authors.initials: AP
authors.lastname: IJzerman
mesh_terms: D000241:Adenosine / Q000502:physiology*; D000244:Adenosine Diphosphate / Q000494:pharmacology; D000248:Adenosine Kinase / Q000037:antagonists & inhibitors; D000249:Adenosine Monophosphate / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology*; D000818:Animals; D017209:Apoptosis; D051379:Mice; D009447:Neuroblastoma / Q000473:pathology; D018048:Receptors, Purinergic P2 / Q000502:physiology*; D058486:Receptors, Purinergic P2X7; D014407:Tumor Cells, Cultured
chemical_list: C546469:P2rx7 protein, mouse; D018048:Receptors, Purinergic P2; D058486:Receptors, Purinergic P2X7; D000249:Adenosine Monophosphate; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D000248:Adenosine Kinase; D000241:Adenosine