title: Redox control of G(1)/S cell cycle regulators during nitric oxide-mediated cell cycle arrest.
abstract: Redox regulation of cell cycle progression during nitric oxide (NO) mediated cytostasis is not well-understood. In this study, we investigated the role of the intracellular antioxidant glutathione (GSH) in regulating specific signaling events that are associated with NO-mediated cell cycle arrest. Manipulation of intracellular GSH content through pharmacological inhibition of glutamate-cysteine ligase (GCL) indicated that GSH depletion potentiated nitrosative stress, DNA damage, phosphorylation of the tumor suppressor p53 (Ser-18) and upregulation of p21(cip1/waf1) upon NO stimulation. However, we found that neither overexpression of a dominant negative p53 nor pharmacological inhibition of p53 with cyclic pifithrin-alpha (cPFT-alpha) was sufficient to reverse NO-mediated cell cycle arrest or hypophosphorylation of retinoblastoma protein (Rb). We found that the decrease in cyclin D1 levels induced by NO was GSH-sensitive implying that the redox regulation of NO-mediated cytostasis was a multifaceted process and that both p53/p21(cip1/waf1) and p53 independent cyclin D1 pathways were involved. Together, our results demonstrate that GSH serves as an important component of cellular protective mechanisms against NO-derived nitrosative stress to regulate DNA damage checkpoint.
authors: Center for Cardiovascular Sciences, Albany Medical College, Albany, NY 12208, USA.
authors: Qi
authors: Q
authors: Lu
authors: Frances L
authors: FL
authors: Jourd'Heuil
authors: David
authors: D
authors: Jourd'Heuil
mesh_terms: D000818:Animals; D052160:Benzothiazoles / Q000494:pharmacology; D019328:Buthionine Sulfoximine / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D049109:Cell Proliferation / Q000187:drug effects*; D056741:Cyclin D; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D004249:DNA Damage; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005347:Fibroblasts / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D016193:G1 Phase / Q000187:drug effects; D005721:Glutamate-Cysteine Ligase / Q000037:antagonists & inhibitors / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism*; D051379:Mice; D041681:NIH 3T3 Cells; D009569:Nitric Oxide / Q000378:metabolism*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D010084:Oxidation-Reduction; D010766:Phosphorylation; D016160:Retinoblastoma Protein / Q000378:metabolism; D016196:S Phase / Q000187:drug effects; D014050:Toluene / Q000031:analogs & derivatives / Q000494:pharmacology; D014162:Transfection; D014226:Triazenes / Q000494:pharmacology*; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: C105351:1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene; D052160:Benzothiazoles; C493957:Cdkn1a protein, mouse; D018797:Cell Cycle Proteins; D056741:Cyclin D; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004791:Enzyme Inhibitors; D020030:Nitric Oxide Donors; D016160:Retinoblastoma Protein; D014226:Triazenes; D016159:Tumor Suppressor Protein p53; D009569:Nitric Oxide; D014050:Toluene; D019328:Buthionine Sulfoximine; C121565:pifithrin; D005721:Glutamate-Cysteine Ligase; D005978:Glutathione