Room temperature-induced apoptosis of Jurkat cells sensitive to both caspase-1 and caspase-3 inhibitors

We recently reported that HL-60 cells underwent apoptosis when exposed to room temperature (RT) (21 degrees C). RT-induced apoptosis of HL-60 cells is inhibited by the caspase-1 inhibitor (YVAD-CMK), but not by the caspase-3 inhibitor (DEVD-CHO). In this study, we studied RT-induced apoptosis in 15 human cell lines of hematopoietic lineage and found that the Jurkat cell line also responded to RT by a different apoptotic process. RT-induced apoptosis of Jurkat cells was attenuated by YVAD-CMK as well as DEVD-CHO. Increased caspase activity on DEVD-AMC, which was inhibited by both YVAD-CMK and DEVD-CHO added to the cell culture, was also detected. The involvement of caspase-3 itself, however, was not recognized by Western blot analysis. In contrast, the processing of caspase-3 was observed in the apoptotic HL-60 cells. These data implicate the presence of the redundant processes of apoptosis induced by RT treatment.