Abstract
Treatment of Jurkat T cells with Fas-activating antibody (CH-11) facilitated rapid cell death that was shown to be caspase-dependent apoptosis. The expression of miR-143 was up-regulated during the apoptosis with time. The increased expression of miR-143 emerged from 1 to 2h after the treatment, at which time the caspases-8 and -3 were also activated; and this increase was almost canceled by the pretreatment with an inhibitor of caspase-3 or -8. Furthermore, the transfection of Jurkat cells with mature miR-143 induced a significant growth suppression and enhancement of CH-11-induced apoptosis. On the contrary, an extracellular signal-regulated protein kinase 5 (ERK5), which was determined to be a target of miR-143 in colon cancer DLD-1 cells, was time-dependently down-regulated at the translational level after the treatment. During the apoptosis, the expression level of FasL was maintained and the level of nuclear-Foxo3a was increased in the early phase. These data suggest that the up-regulation of miR-143 could be related to the apoptosis in part by targeting ERK5, which leads to promotion of Foxo3a/FasL positive feedback loop.