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Induction of apoptosis by 1,4-benzothiazine analogs in mouse thymocytes
C Marchetti1, S Ulisse, S Bruscoli
1Department of Clinical and Experimental Medicine, University of Perugia, Perugia, Italy.
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.
Insights
1,4-benzothiazine derivatives induce apoptosis in mouse thymocytes, impacting thymus cell loss. Structure-activity relationships reveal key chemical features influencing this apoptotic effect.
Area of Science:
- Biochemistry
- Toxicology
- Cell Biology
Background:
- 1,4-benzothiazine (1,4-B) derivatives exhibit diverse biological activities, including neurotoxicity and antitumor effects.
- Understanding the mechanisms of 1,4-B-induced cytotoxicity is crucial for therapeutic development.
Purpose of the Study:
- To investigate the apoptotic mechanisms underlying 1,4-benzothiazine-induced cytotoxicity.
- To evaluate the structure-activity relationship of 1,4-B analogs regarding their apoptotic potential.
Main Methods:
- Experiments were conducted using mouse thymocytes, a sensitive model for apoptosis induction.
- In vitro and in vivo assays were employed to assess thymocyte apoptosis and thymus cell loss.
- Biochemical analyses were performed to identify key events in the apoptotic pathway.
Main Results:
- Several 1,4-B analogs induced thymocyte apoptosis in vitro and thymus cell loss in vivo.
- Apoptotic efficacy was modulated by the sulfur oxidation state, carbonyl group, and side chain characteristics of 1,4-B derivatives.
- 1,4-B-induced apoptosis involved phosphatidylcholine-specific phospholipase C and acidic sphingomyelinase activation, ceramide generation, mitochondrial membrane potential loss, cytochrome c release, and caspase activation.
Conclusions:
- 1,4-benzothiazine derivatives trigger apoptosis through a complex cascade of biochemical events.
- The findings provide insights into the cytotoxic mechanisms of 1,4-B compounds and their structure-activity relationships.