title: Roles of Ras-Erk in apoptosis of PC12 cells induced by trophic factor withdrawal or oxidative stress.
abstract: To understand the role of Ras-MAPK (mitogen-activated protein kinase) in trophic factor withdrawal- and oxidative stress-induced apoptotic cell death processes, undifferentiated rat pheochromocytoma PC12 cells and a PC12 variant cell line stably expressing the Ras dominant-negative mutant (M-M17-26) were subjected to serum withdrawal in the absence or presence of H2O2 treatment. The extent of cell death was analyzed by lactate dehydrogenase release, internucleosomal DNA fragmentation, and caspase-3 assays. Both serum withdrawal and H2O2 treatment induced apoptotic cell death in PC12 cells, and the extent of cell death was greatly enhanced in M-M17-26 cells. DNA fragmentation induced by serum withdrawal or H2O2 treatment was blocked completely by a general caspase inhibitor, Z-VAD-FMK. A selective MAPK kinase inhibitor, U0126, blocked the H2O2-induced phosphorylation of Erk1/2 (extracellular signal-regulated kinase) in PC12 cells and increased the levels of active caspase-3 in M-M17-26 under serum withdrawal or H2O2 treatment. In addition, the short-term H2O2 treatment (5-30 min) was sufficient to cause DNA fragmentation in M-M17-26 cells even though H2O2 was removed and cells were incubated in regular growth medium with complete serum for 24 h. However, similar, short-term H2O2 treatment of PC12 cells did not induce DNA fragmentation 24 h later. These results suggest that the Ras-Erk pathway is critical in mediating protection against apoptotic cell death induced by either trophic factor withdrawal or increased oxidative stress.
authors.affiliation: William T. Gossett Neurology Laboratories, Henry Ford Health System, Detroit, MI 48202. USA.
authors.forename: Hao
authors.initials: H
authors.lastname: Jiang
authors.forename: Lijie
authors.initials: L
authors.lastname: Zhang
authors.forename: David
authors.initials: D
authors.lastname: Koubi
authors.forename: Jarret
authors.initials: J
authors.lastname: Kuo
authors.forename: Laurent
authors.initials: L
authors.lastname: Groc
authors.forename: Alba I
authors.initials: AI
authors.lastname: Rodriguez
authors.forename: Tangella Jackson
authors.initials: TJ
authors.lastname: Hunter
authors.forename: Stephen
authors.initials: S
authors.lastname: Tang
authors.forename: Philip
authors.initials: P
authors.lastname: Lazarovici
authors.forename: Subhash C
authors.initials: SC
authors.lastname: Gautam
authors.forename: Robert A
authors.initials: RA
authors.lastname: Levine
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D002070:Butadienes / Q000494:pharmacology; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D016895:Culture Media, Serum-Free / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D015870:Gene Expression; D011905:Genes, ras / Q000235:genetics / Q000502:physiology*; D006861:Hydrogen Peroxide / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D009474:Neurons / Q000166:cytology* / Q000201:enzymology; D009570:Nitriles / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D018384:Oxidative Stress / Q000502:physiology*; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats
chemical_list: D002070:Butadienes; D016895:Culture Media, Serum-Free; D004791:Enzyme Inhibitors; D009570:Nitriles; D016877:Oxidants; C113580:U 0126; D006861:Hydrogen Peroxide; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020930:MAP Kinase Kinase Kinases; C505410:Casp3 protein, rat; D053148:Caspase 3; D020169:Caspases