title: Induction of apoptosis by 1,4-benzothiazine analogs in mouse thymocytes.
abstract: 1,4-benzothiazine (1,4-B) derivatives exert numerous effects in vivo and in vitro, including neurotoxicity and antitumor cytotoxicity. To analyze the mechanisms responsible for 1,4-B-induced cytotoxicity, we performed experiments to evaluate the possible apoptotic effect. For that purpose, we used mouse thymocytes, a cell population well sensitive to induction of apoptosis that has been used to assay apoptosis in many experimental systems. Results indicate that a number of 1,4-B analogs are able to induce both thymocyte apoptosis in vitro and thymus cell loss in vivo. Moreover, analysis of the structure-activity relationship indicate that the sulfur (S) oxidation state, the presence of the carbonyl group, and the nature and position of the side chain modulate the apoptotic efficacy. Moreover, results of in vitro experiments show that the 1,4-B-induced apoptosis associates with different biochemical events including phosphatidylcholine-specific phospholipase C activation, acidic sphingomyelinase activation and ceramide generation, loss of mitochondrial membrane potential (DeltaPsi(m)) and cytochrome c release, and caspase-8, -9, and -3 activation. These results indicate that 1,4-B analogs induce apoptosis through a complex of biochemical events.
authors.affiliation: Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Marchetti
authors.forename: S
authors.initials: S
authors.lastname: Ulisse
authors.forename: S
authors.initials: S
authors.lastname: Bruscoli
authors.forename: F P
authors.initials: FP
authors.lastname: Russo
authors.forename: G
authors.initials: G
authors.lastname: Migliorati
authors.forename: F
authors.initials: F
authors.lastname: Schiaffella
authors.forename: M G
authors.initials: MG
authors.lastname: Cifone
authors.forename: C
authors.initials: C
authors.lastname: Riccardi
authors.forename: R
authors.initials: R
authors.lastname: Fringuelli
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects*; D020169:Caspases / Q000378:metabolism; D002518:Ceramides / Q000096:biosynthesis; D003574:Cytochrome c Group / Q000378:metabolism; D053938:DNA Fragmentation; D004789:Enzyme Activation / Q000187:drug effects; D005470:Fluorometry; D008564:Membrane Potentials / Q000187:drug effects; D051379:Mice; D008809:Mice, Inbred C3H; D008928:Mitochondria / Q000187:drug effects; D013108:Sphingomyelin Phosphodiesterase / Q000378:metabolism; D013268:Stimulation, Chemical; D013329:Structure-Activity Relationship; D013601:T-Lymphocytes / Q000187:drug effects* / Q000378:metabolism; D013843:Thiazines / Q000737:chemistry / Q000494:pharmacology*; D010738:Type C Phospholipases / Q000378:metabolism
chemical_list: C446962:1,4-benzothiazine; D002518:Ceramides; D003574:Cytochrome c Group; D013843:Thiazines; D010738:Type C Phospholipases; D013108:Sphingomyelin Phosphodiesterase; D020169:Caspases