| Summary: | 碩士 === 國立交通大學 === 生物科技學系 === 99 === Vitamin K derivatives have been shown to exert anticancer activities. In this report, we found a novel vitamin K derivative, CR-108, which studied its molecular mechanism on apoptosis induction in the human breast cancer cells. Treatment with 2-8 μM CR-108 for 24 h reduced the cell viability via a concentration-dependent manner in both the non-HER-2-overexpressed MCF-7 and HER-2-overexpressed BT-474 breast cancer cells. Interestingly, CR-108 highly elicited the intracellular reactive oxygen species (ROS) level by staining with H2DCF-DA and detected using flow cytometer and confocal microscope in MCF-7 cells. CR-108 markedly induced the loss of mitochondrial membrane potential (ΔΨm) analysed by fluorescence intensities of JC-1 and DiOC6. CR-108 induced cytochrome c release from mitochondria to cytosol, elevated the levels of cleaved PARP proteins, and increased apoptotic induction. Treatment with a ROS scavenger NAC (5 mM for 24 h) completely blocked the CR-108-induced ROS generation, mitochondrial damage, and apoptosis. Meantime, CR-108 elicited the phosphorylations of p38 mitogen-activated protein (MAP) kinase and p53 (Ser-15) but conversely inhibited survivin protein expression. Treatment with NAC reduced the phosphorylated p38 MAP kinase and p53 (Ser-15) proteins and restored the survivin protein level. SB202190, a specific p38 MAP kinase inhibitor, restored the survivin protein level and attenuated CR-108-induced cytotoxicity. However, treatment with a specific p53 inhibitor, pifithrin-α, enhanced the CR-108-induced cancer cell death. In addition, CR-108 induced cell cycle arrest in MCF-7 cells and NAC restored the CR-108-induced cell cycle arrest. Taken together, we suggest that CR-108 induces apoptosis through ROS generation and mitochondrial damage pathway, and p38 MAP kinase, p53 and survivin play important roles in regulating apoptosis in the human breast cancer cells.
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