Etoposide activates caspase-3 via a caspase-1 independent mechanism in cancer cells

It is known that caspase-1 is activated before caspase-3 activation when the cells were treated with anti-Fas-antibody. In present study the activities of these two proteases in etoposide-treated cells were examined. It has been shown that whilst treatment of U937 and Jurkat cells with etoposide results in caspase-3 activation it did not influence caspase-1 activity. At the same time treatment of U937 cells with anti-Fas antibody induces caspase-1 activity. These results demonstrate that etoposide transmits the death signal to caspase-3 directly, suggesting that caspase-3 was activated by a caspase-1 independent mechanism during etoposide-induced apoptosis.