Investigation of the mechanism of apoptosis of the TNF-related apoptosis inducing ligand-susceptible Jurkat cells induced by cross-linking antideath receptor-5 YM366EC

To observe the effect of the cross-linking anti-death receptor-5(DRS)YM366EC on the TNF-related apoptosis in- ducing ligand(TRAIL)and to elucidate the anti-tumor mechanism of their interaction,the morphological changes induced by the cross-linking anti-YM366EC monoclonal antibody were observed microscopically,and its cytotoxic and apoptotic effects were detected with MTT assay and flow cytometry(FCM).Meanwhile,the changes in the expressions of Bcl-2,Cyt-C,Bax, Caspase-3,Caspase-5 and Caspase-9 after different period of time were further determined by Western blotting.The result showed that after treatment with DR5 antibody YM366EC alone,no apoptotic change could be found,but when Jurkat cells were treating with the mouse IgG cross-linking with 366EC,chromatin margination,budding and appearance of the apoptotic bodies could be demonstrated in these cells,and it also induced the apoptosis of the TRAIL-susceptible Jurkat ceils.As dem- onstrated by Western blotting analysis,along with the prolongation of the induction time with antibody,the expression of Bcl- 2 protein in Jurkat cells decreased,and those of Cyt-C,Bax,active Caspase-3 and Caspase-9 proteins increased.It is evident that definite inhibitory effect can be demonstrated on Jurkat cells after treatment with cross-linking anti-DR5 antibody YM366EC,and the molecular mechanism of apoptosis induced by this antibody may involve with Cyt-C,Bax,Caspase-3 and Caspase-9.