中文摘要：

目的探讨氟喹诺酮类化合物三甲氧基苯甲醛环丙沙星席夫碱诱导人肝癌SMMC-7721细胞凋亡作用。方法用不同浓度的1-环丙基-6-氟-7-（哌嗪-1-基）-3-[5．苄硫基-4-（3，4，5．三甲氧苯甲叉基氨基）-1，2，4-三唑．3．基]-喹啉（1-日）4硼（M27）与人肝癌SMMC-7721细胞、结肠癌HCT-116细胞株、白血病JURKET细胞株体外培养。M1Tr法检测M27及其前体化合物环丙沙星盐酸盐对肿瘤细胞的增殖抑制作用；Hoechst33258荧光染色法、TUNEL法检测细胞凋亡变化；以pBR322DNA为底物，琼脂糖电泳法检测M27对拓扑异构酶Ⅱ的活性的影响；高内涵活细胞成像系统测定线粒体跨膜电位（AtOm）变化；Westernblotting法检测D53、Caspase-9、Caspase-3、Caspase-8、Bcl-2和Bax等凋亡相关蛋白的表达以及细胞色素c在线粒体内外分布的变化。结果M27在lO～60μmol·L-1内抑制肿瘤细胞增殖，呈浓度、时间依赖性。作用于5MMC-7721细胞、HCT-116细胞、JURKET细胞24hIC50值分别为37．97、46．07、44．33μmol·L-1，而环丙沙星盐酸盐对SMMC-7721细胞增殖抑制作用不显著。各组M27作用于SMMC-7721细胞24h，细胞凋亡率显著高于对照组（P〈0．05），并伴有细胞线粒体膜电位（△Фm）降低。与对照组比较，M27能够抑制DNA拓扑异构酶Ⅱ的活性，使细胞p53、Bax、Caspase-8、Caspase-9和Caspase．3蛋白表达及活性片段增加，Bcl-2的表达量降低；线粒体细胞色素C减少，胞浆细胞色素C增多。结论三甲氧基苯甲醛环丙沙星席夫碱能够抑制拓扑异构酶Ⅱ的活性，造成DNA损伤，诱导人肝癌SMMC．772l细胞凋亡。

英文摘要：

OBJECTIVE To investigate the effect of 1-cyclopropyl-6-fluoro-7-（piperazin-l-yl）-3-[5-benzylsulfanyl-4-（3,4,5-tri- methoxybenzylidene） amino-4H-1,2,4-triazol-3-yl ] -quinolin-4 （ 1 H） -one （M27） on apoposis in hepatocarcinoma SMMC-7721 cells in vitro. METHODS SMMC-7721 cells, colon adenocarcinoma cells （HCT-116）and leukemia cell line JURKET were treated by M27 with different concentrations for different time in vitro, the inhibitory effect of M27 and its precursor ciprofloxacin on the cell prolifera- tion were examined by MTT assay. Cell apoptosis was determined by Hoechst 33258 fluorescence staining and TUNEL assay. The effect of M27 on topoisomerase lI activity was measured using agarose gel electrophoresls by Plasmid pBPt322 DNA as the substrate. Mito- chondrial membrane potential（/tt~m） was measured by high content screening imaging system. The p53,Caspase-9,Caspase-3,Caspase- 8, Bcl-2,Bax and cytochrome C protein expressions were determined by Western blotting analysis. RESULTS The proliferation of the cancer cells was inhibited by M27 at 10 -60 μmol·L-1 in time-and dose-dependent manner. Ciprofloxacin showed weak cytotoxicity against SMMC-7721 cell. SMMC-7721 cells treated by M27 with different concentrations for 24 h increased the percentage of apoptosis ceils obviously （P 〈 0. 05 ） with a decrease in the mitochondrial membrane potential. Compared with control group, M27 influenced ob- viously DNA topoisomerase Ⅱ activity, stimulated DNA cleavage and inhibited DNA reunion mediated by topoisomerase Ⅱ. In addi- tion, M27 increased protein expression of p53, Bax, Caspase-8, Caspase-9, Caspase-3, as well as the cleaved activated forms of Caspase-9, Caspase-8 and Caspase-3 significantly, whereas the expression of Bcl-2 decreased. There was a significant increase of cyto- chrome C in the cytosol after 24 h of treatment with M27 and a decrease in the mitoehondrial compartment. CONCLUSION M27 as a fluoroquinolone derivative exerted potent anticancer activity through the mechanis