Experimental cell research
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Brefeldin A (BFA) has recently been shown to induce apoptosis in human tumor cells in a p53-independent fashion. In this study, BFA-induced apoptosis was analyzed in the human Jurkat T-cell line. Apoptosis occurred 8 h after treatment with BFA and at concentrations as low as 10 ng/ml and increased with the duration of BFA exposure. ⋯ Z-Phe-Ala-FMK, a cysteine protease inhibitor lacking aspartate at the P1 position, did not have any impact on BFA-induced apoptosis. Furthermore, Jurkat cells transfected with the proto-oncoprotein Bcl-2, which is able to block various apoptotic conditions, showed remarkable resistance to the apoptotic effect of BFA. Thus, the data indicate that BFA-induced apoptosis requires caspase(s) activation, primarily the activation of caspase-3, and is inhibited by overexpression of Bcl-2.