Inhibition of ultraviolet B (UVB) induced apoptosis in A431 cells by mimosine is not dependent on cell cycle arrest.
Ultraviolet (UV) radiation is a strong apoptotic trigger in many cell types. We have previously reported that a plant amino acid, mimosine (beta [N-(3-hydroxy-4-pyridone)]-alpha-aminopropionic acid), with a well-known reversible G1 cell cycle arrest activity can inhibit apoptosis induced by UV irradiation and RNA polymerase II blockage in human A431 cells. Here, apoptosis was measured with a fluorimetric caspase activation assay. Interestingly, the protective state was effective up to 24 h following removal of mimosine from the culture medium while cells were progressing in the cell cycle. Our results demonstrate that the protective effect of mimosine against UV-induced apoptosis can be dissociated from its G1 cell-cycle arrest activity.
CIHR Group in the Radiation Sciences, Faculté de médecine, Université de Sherbrooke, QC, Canada.
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D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects*; D053148:Caspase 3; D061945:Caspase Inhibitors; D020169:Caspases / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects* / Q000528:radiation effects*; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D006801:Humans; D008898:Mimosine / Q000494:pharmacology*; D012319:RNA Polymerase II / Q000037:antagonists & inhibitors; D011837:Radiation-Protective Agents / Q000494:pharmacology*; D014407:Tumor Cells, Cultured; D014466:Ultraviolet Rays
D061945:Caspase Inhibitors; D011837:Radiation-Protective Agents; D008898:Mimosine; D012319:RNA Polymerase II; C505407:CASP3 protein, human; D053148:Caspase 3; D020169:Caspases