title: Hypoxia sensitizes cells to nitric oxide-induced apoptosis.
abstract: Nitric oxide (NO) can induce apoptosis in a variety of cell types. A non-toxic concentration of nitric oxide under normal oxygen conditions triggered cell death under hypoxic conditions (1.5% O(2)) in fibroblasts. Nitric oxide administered during hypoxia induced the release of cytochrome c, caspase-9 activation, and the loss of mitochondrial membrane potential followed by DNA fragmentation and lactate dehydrogenase release (markers of cell death). Bcl-X(L) protected cells from nitric oxide-induced apoptosis during hypoxia by preventing the release of cytochrome c, caspase-9 activation, and by maintaining a mitochondrial membrane potential. Murine embryonic fibroblasts from bax(-/-) bak(-/-) mice exposed to nitric oxide during hypoxia did not die, indicating that pro-apoptotic Bcl-2 family members are required for NO-induced apoptosis during hypoxia. The nitric oxide-induced cell death during hypoxia was independent of cGMP and peroxynitrite. Cells devoid of mitochondrial DNA (rho secondary-cells) lack a functional electron transport chain and were resistant to nitric oxide-induced cell death during hypoxia, suggesting that a functional electron transport chain is required for nitric oxide-induced apoptosis during hypoxia.
authors.affiliation: Division of Pulmonary and Critical Care Medicine, Department of Medicine, Northwestern University Medical School, Chicago, Illinois 60611, USA.
authors.forename: Vivian Y
authors.initials: VY
authors.lastname: Lee
authors.forename: David S
authors.initials: DS
authors.lastname: McClintock
authors.forename: Matthew T
authors.initials: MT
authors.lastname: Santore
authors.forename: G R Scott
authors.initials: GR
authors.lastname: Budinger
authors.forename: Navdeep S
authors.initials: NS
authors.lastname: Chandel
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D015687:Cell Hypoxia / Q000502:physiology*; D002460:Cell Line; D003847:Deoxyglucose / Q000494:pharmacology; D004622:Embryo, Mammalian; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D005354:Fibrosarcoma; D051379:Mice; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000494:pharmacology*; D051381:Rats; D014226:Triazenes / Q000494:pharmacology; D014407:Tumor Cells, Cultured
chemical_list: C105351:1-hydroxy-2-oxo-3,3-bis(2-aminoethyl)-1-triazene; D020030:Nitric Oxide Donors; D014226:Triazenes; D009569:Nitric Oxide; D003847:Deoxyglucose