Mitochondrial permeability transition is a central coordinating event in N-(4-hydroxyphenyl)retinamide-induced apoptosis.
The inhibitory effects of N-(4-hydroxyphenyl)retinamide (4HPR) on the process of carcinogenesis are not fully understood and may result from its ability to induce apoptosis in transformed cells. This study investigated the apoptotic properties of 4HPR in four human cutaneous squamous cell carcinoma cell lines. Apoptosis induction, detected by the terminal deoxynucleotidyl transferase dUTP nick end labeling method, occurred in a dose- and time-dependent fashion after treatment with 4HPR. 4HPR promoted reactive oxygen species (ROS) determined by oxidation of 2',7'-dichlorofluorescin. 4HPR-induced ROS, and apoptosis could be inhibited by L-ascorbic acid. Rhodamine 123 retention revealed that 4HPR treatment promoted a gradual dissipation of mitochondrial inner transmembrane potential, and this could be inhibited by L-ascorbic acid, implying that mitochondrial permeability transition was involved in apoptosis induction. Cyclosporin A and bongkrekic acid inhibited dissipation of mitochondrial inner transmembrane potential, ROS production, and DNA fragmentation after exposure to 4HPR, demonstrating that mitochondrial permeability transition was a central coordinating feature of 4HPR-induced apoptosis.
Hail
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Department of Thoracic/Head and Neck Medical Oncology, The University of Texas M. D. Anderson Cancer Center, Houston 77030-4095, USA.
Lotan
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D016588:Anticarcinogenic Agents / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D001205:Ascorbic Acid / Q000494:pharmacology; D002294:Carcinoma, Squamous Cell / Q000503:physiopathology; D002455:Cell Division / Q000187:drug effects; D016572:Cyclosporine / Q000494:pharmacology; D053938:DNA Fragmentation; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D004791:Enzyme Inhibitors / Q000494:pharmacology; D017313:Fenretinide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D005452:Fluoresceins / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D006801:Humans; D007425:Intracellular Membranes / Q000187:drug effects* / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008928:Mitochondria / Q000187:drug effects* / Q000502:physiology; D010084:Oxidation-Reduction; D010539:Permeability; D017382:Reactive Oxygen Species / Q000378:metabolism; D020112:Rhodamine 123 / Q000378:metabolism; D012878:Skin Neoplasms / Q000503:physiopathology; D014407:Tumor Cells, Cultured / Q000187:drug effects
D016588:Anticarcinogenic Agents; D004791:Enzyme Inhibitors; D005452:Fluoresceins; D005456:Fluorescent Dyes; D017382:Reactive Oxygen Species; D017313:Fenretinide; D020112:Rhodamine 123; C037631:2',7'-dichlorofluorescein; D016572:Cyclosporine; D001205:Ascorbic Acid