MODULATION OF THE RADIATION-INDUCED APOPT OSIS BY AC-DEVD-CHO AN ICE-LIKE PROTEASES INHIBITOR

The ''ICE-like'' proteases, recently renamed caspases, are the human h omologues of the Caenarhabditis elegans ced-3 gene product and are act ivated in the early steps of apoptosis. The aim of this work is to det ermine whether the inhibition of one of these proteases, namely caspas e-3, is able to modify the cell sensitivity toward radiation-induced a poptosis. Murine spleen lymphocytes submitted to gamma-radiations in p resence of Ac-DVED-CHO, a caspase-3 specific inhibitor, exhibit a shar ply reduced number of radiation-induced hypodiploid particules as comp ared to the controls and an almost total inhibition of the internucleo somal DNA fragmentation. However, both the anionic phospholipids exter nalisation, another specific hallmark of apoptosis, and the viability remain unchanged.