| Summary: | 碩士 === 國立陽明大學 === 醫學生物技術研究所 === 89 === ABSTRACT
Induction of apoptosis and necrosis by paclitaxel was investigated on human leukemic U937 cells. To explore the role of paclitaxel-induced apoptosis and necrosis in cell cycle, synchronized cells in G1, S and G2/M stages were employed for comparative analysis. Our investigations suggest that the cells of G1 and S stages treated with paclitaxel died predominantly through apoptosis, whereas G2/M-stage cells died through both apoptosis and necrosis. This phenomenon was verified by colony formation assay. Conditioned medium of paclitaxel-treated U937 cells, especially in G2/M stage, may inhibit cell growth. These results suggest that necrosis was involved in the paclitaxel-treated G2M-cells which may release certain substances to induce cell death. In the process of necrosis, proteins released from cytoplasm due to the disruption of membrane. The released inhibitory substances were possibly proteins and their activity required the aid of certain low molecular weight substances. Our studies also demonstrated that the mitochondrial events involved in apoptosis after paclitaxel treatment occur more significantly in S stage than in G1 and G2/M stages. This supports that the cells of G1 and S stages treated with paclitaxel died predominantly through apoptosis, whereas G2/M-phase cells died through both apoptosis and necrosis.
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