title: Bcl-x(S) induces an NGF-inhibitable cytochrome c release.
abstract: Bcl-x(S), a pro-apoptotic member of the Bcl-2 protein family, is localized in the mitochondrial outer membrane and induces caspase-dependent and nerve growth factor (NGF)-inhibitable apoptosis in PC12 cells. The mechanism of action of Bcl-x(S) and how NGF inhibits this death are not fully understood. It is still unknown whether Bcl-x(S) induces mitochondrial cytochrome c release, and which apoptotic step NGF inhibits. We show that Bcl-x(S) induces cytochrome c release and caspase-3 activation in several cell types, and that in PC12 cells, these events are inhibited by NGF treatment. The survival effect of NGF was inhibited by inhibitors of protein kinase C (PKC), phosphatidylinositol-3-kinase (PI 3-kinase), and the mitogen-activated protein kinase kinase (MEK) inhibitors GF109203X, LY294002, and U0126. These findings show that cytochrome c release and caspase-3 activation participate in Bcl-x(S)-induced apoptosis, and that NGF inhibits Bcl-x(S)-induced apoptosis at the mitochondrial level via the PKC, PI 3-kinase, and MEK signaling pathways.
authors.affiliation: Department of Neurobiochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv 69978, Israel.
authors.forename: Liora
authors.initials: L
authors.lastname: Lindenboim
authors.forename: Sarah
authors.initials: S
authors.lastname: Schlipf
authors.forename: Thomas
authors.initials: T
authors.lastname: Kaufmann
authors.forename: Christoph
authors.initials: C
authors.lastname: Borner
authors.forename: Reuven
authors.initials: R
authors.lastname: Stein
mesh_terms: D000818:Animals; D017209:Apoptosis; D002070:Butadienes / Q000494:pharmacology; D019556:COS Cells; D020169:Caspases / Q000378:metabolism; D002470:Cell Survival; D002522:Chlorocebus aethiops; D002867:Chromones / Q000494:pharmacology; D045304:Cytochromes c / Q000378:metabolism*; D004789:Enzyme Activation; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D015870:Gene Expression; D007211:Indoles / Q000494:pharmacology; D008301:Maleimides / Q000494:pharmacology; D020929:Mitogen-Activated Protein Kinase Kinases / Q000037:antagonists & inhibitors / Q000187:drug effects; D009025:Morpholines / Q000494:pharmacology; D020932:Nerve Growth Factor / Q000494:pharmacology*; D009570:Nitriles / Q000494:pharmacology; D016716:PC12 Cells; D019869:Phosphatidylinositol 3-Kinases / Q000187:drug effects; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D051020:bcl-X Protein
chemical_list: D002070:Butadienes; D020169:Caspases; D002867:Chromones; D045304:Cytochromes c; D007211:Indoles; D008301:Maleimides; D020929:Mitogen-Activated Protein Kinase Kinases; D009025:Morpholines; D020932:Nerve Growth Factor; D009570:Nitriles; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011493:Protein Kinase C; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; C494813:Bcl2l1 protein, rat; C113580:U 0126; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one; C070515:bisindolylmaleimide I