The Significance and Establishment of Cell Cycle Specific Apoptosis Model Induced by Recombinant Human Fas Ligand in Vitro

Abstract: The target cells—leukaemia cell lines (Molt-4 and Jurkat) and peripheral blood lymphocyte were incubated with recombinant human Fas ligand for 6 to 36 hours， apoptosis was detected by sub-G₁， traditional annexin-V/PI and modified API methods. Meanwhile， Fas expression in such cells'' membrane was labelled and the rule of cyclin expression in Fas-mediated apoptosis was studied as well， so as to clarifying the correlation of Fas-mediated apoptosis and cell cycle progression. The data showed that apoptosis induced by recombinant human Fas ligand was cell cycle specific and initiated at G₁-phase in the leukaemia cell lines and activated peripheral blood lymphocyte stimulated by phytohemagglutinin， whereas apoptosis in peripheral blood lymphocyte at G₀-phase could not be induced effectively. Moreover， cyclin D3 expression increased and cyclin E expression decreased evidently during the induction of apoptosis while the expression of cyclins A and B1 was unaltered. These findings indicated that Fas-mediated apoptosis was located at late G₁-phase and determined by whether the target cells had passed through the restriction point to cell division cycle or not. And the cell cycle specificity of Fas-mediated apoptosis was the result of the cells with DNA damage being blocked at late G₁-phase， due to the decrease of cyclin E expression and under the surveillance of G₁-phase check point.
    

CSTR: 32200.14.cjcb.2007.01.0022