title: Caspase-3: its potential involvement in Cr(III)-induced apoptosis of lymphocytes.
abstract: In this study, we have examined the role of caspase-3 in apoptosis of lymphocytes induced by the chromium(III) complexes viz. tris-(1,10-phenanthroline)chromium(III) chloride (Cr(III)-phen) and trans-diaqua[1,3-bis(salicylideneamino)propanechromium(III)] perchlorate (Cr(III)-salprn). Evidence for caspase-3 activation and poly(ADP-ribose) polymerase (PARP) cleavage in lymphocytes exposed to Cr(III) complexes is revealed through Western blotting analysis. Blocking the activity of caspase-3 with z-DEVD-fmk, prevents apoptosis as evidenced through [3H]-thymidine incorporation, DNA fragmentation assay and measurement of sub-G1 cells by flow cytometry. Pretreatment of lymphocytes with free radical scavengers completely attenuates the activity of caspase-3 suggesting that reactive oxygen species (ROS) are upstream activators of caspase-3. Preincubation of lymphocytes with PP2, a selective Src-family tyrosine kinase inhibitor, abolishes the activation of caspase-3 indicating that Src-family tyrosine kinases viz. p56lck, p59fyn and p53/56lyn are mediators of caspase-3 activation during Cr(III) exposure. Collectively, our findings support a plausible mechanism in which Cr(III) mediates ROS generation that precedes the up-regulation of p56lck, p59fyn and p53/56lyn which eventually activates caspase-3 to promote apoptotic cell death of lymphocytes. To our knowledge, this is the first report suggesting the importance of Src-family tyrosine kinases for the activation of caspase-3 in metal-induced apoptotic cell death.
authors.affiliation: Biochemistry Laboratory, Central Leather Research Institute, Adyar, Chennai, India.
authors.forename: Kuppusamy
authors.initials: K
authors.lastname: Balamurugan
authors.forename: Rama
authors.initials: R
authors.lastname: Rajaram
authors.forename: Thirumalachari
authors.initials: T
authors.lastname: Ramasami
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology*; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D017608:Chromium Compounds / Q000633:toxicity*; D015853:Cysteine Proteinase Inhibitors / Q000494:pharmacology; D004247:DNA / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D016166:Free Radical Scavengers / Q000494:pharmacology; D016193:G1 Phase / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism* / Q000473:pathology; D009842:Oligopeptides / Q000494:pharmacology; D009942:Organometallic Compounds / Q000633:toxicity*; D010618:Phenanthrolines / Q000633:toxicity*; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: C417305:(Cr(salprn)(H2O)2)ClO4; D061945:Caspase Inhibitors; D017608:Chromium Compounds; D015853:Cysteine Proteinase Inhibitors; D016166:Free Radical Scavengers; D009842:Oligopeptides; D009942:Organometallic Compounds; D010618:Phenanthrolines; D017382:Reactive Oxygen Species; C110772:benzoylcarbonyl-aspartyl-glutamyl-valyl-aspartyl-fluoromethyl ketone; C495433:tris(1,10-phenanthroline)chromium(III) chloride; D004247:DNA; D011065:Poly(ADP-ribose) Polymerases; D019061:src-Family Kinases; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases