双歧杆菌对大肠癌的抑瘤作用及对其信号转导的影响

发布时间：2018-08-26 13:38

【摘要】： 目的探索双歧杆菌对肿瘤的抑制作用，并从信号转导这一层次探索青春双歧杆菌的抑瘤途径。方法将青春双歧杆菌体外直接作用于大肠癌LoVo细胞，以MTT法、流式细胞仪法和免疫细胞化学方法分别测定了双歧杆菌对肿瘤细胞的杀伤作用及其对肿瘤细胞周期、细胞凋亡、酪氨酸激酶(PTK)的活性以及核因子(NF-κB)的活化状况的影响。结果本实验中MTT结果显示双歧杆菌对体外培养的大肠癌LoVo细胞具有明显的生长抑制作用，且双歧杆菌的浓度越大、作用时间越长，其对肿瘤的抑制作用越强，具有浓度和时间依赖性。经浓度为1×10~7CFU／ml的青春双歧杆菌作用72h后，其对大肠癌LoVo细胞的生长抑制率达到52％，经浓度为1×10~(11)CFU／ml的双歧杆菌作用72h后，，其对大肠癌LoVo细胞的生长抑制率达到78％(P0．05)。流式细胞仪检测发现，浓度为1×10~9CFU／ml的双歧杆菌作用48h后能将肿瘤细胞阻滞于G_0／G_1期，在细胞周期G_1峰的左侧出现了凋亡峰。流式细胞仪法检测细胞凋亡发现，双歧杆菌具有诱导大肠癌细胞凋亡的作用与细胞周期所得结果一致，肿瘤对照组细胞凋亡率为(9．48±0．91)％，经浓度为1×10~7CFU／ml的双歧杆菌作用48h后，肿瘤细胞的凋亡率为(26．37±2．41)％，经浓度为1×10~9CFU／ml的双歧杆菌作用48h后，肿瘤细胞的凋亡率为(40．99±1．66)％(P0．05)。双歧杆菌作用组PTK的荧光强度显著低于肿瘤对照组(P0．01)，表明双歧杆菌能降低大肠癌LoVo细胞PTK的活性。免疫组细胞化学结果显示，双歧杆菌作用组的NF-κB的表达明显低于肿瘤对照组(P0．05)。结论本实验发现双歧杆菌对肿瘤细胞具有生长抑制作用，可以诱导大肠癌LoVo细胞凋亡，将肿瘤细胞阻滞在G_1期，同时降低肿瘤细胞PTK的活性，抑制NF-κB的活化。双歧杆菌抑制肿瘤的途径可能通过诱导肿瘤细胞凋亡及影响肿瘤细胞信号转导途径中的关键信号分子的活性与表达。图[17]表[5]参[59]
[Abstract]:Objective to explore the inhibitory effect of Bifidobacterium on tumor and explore the inhibition pathway of Bifidobacterium pubertii from signal transduction level. Methods Bifidobacterium pubericiae was directly exposed to colorectal cancer LoVo cells in vitro. The killing effect of bifidobacterium on tumor cells, cell cycle and apoptosis were determined by MTT, flow cytometry and immunocytochemistry, respectively. Effects of tyrosine kinase (PTK) activity and activation of NF- 魏 B. Results the results of MTT showed that Bifidobacterium could inhibit the growth of LoVo cells in vitro, and the higher the concentration of Bifidobacterium, the longer the time of action, the stronger the inhibitory effect of Bifidobacterium on the tumor. It is concentration-dependent and time-dependent. After 72 hours of treatment with 1 脳 10~7CFU/ml Bifidobacterium pubernum, the growth inhibition rate of LoVo cells reached 522%. After 72 hours of treatment with 1 脳 10 ~ (11) CFU/ml Bifidobacterium, the growth inhibition rate of LoVo cells was 78% (P0.05). Flow cytometry showed that Bifidobacterium at concentration of 1 脳 10~9CFU/ml could block tumor cells in G_0/G_1 phase after 48 h, and apoptosis peak appeared on the left side of cell cycle G _ (1) peak. The results of flow cytometry showed that Bifidobacterium could induce the apoptosis of colorectal cancer cells, and the apoptosis rate of tumor control group was (9.48 卤0.91). The apoptotic rate of tumor cells was (26.37 卤2.41) after exposure to 1 脳 10~7CFU/ml bifidobacterium for 48 h, and (40.99 卤1.66)% (P0.05) after 48 h treatment with 1 脳 10~9CFU/ml Bifidobacterium. The fluorescence intensity of PTK in Bifidobacterium treated group was significantly lower than that in tumor control group (P0.01), which indicated that Bifidobacterium could reduce the activity of PTK in LoVo cells of colorectal cancer. The expression of NF- 魏 B in the bifidobacterium treated group was significantly lower than that in the tumor control group (P0.05). Conclusion Bifidobacterium can inhibit the growth of tumor cells, induce the apoptosis of LoVo cells, block the tumor cells in G _ 1 phase, decrease the activity of PTK and inhibit the activation of NF- 魏 B. Bifidobacterium inhibits tumor cells by inducing apoptosis and affecting the activity and expression of key signal molecules in the signal transduction pathway of tumor cells. Fig [17] Table [5] Ref [59]
【学位授予单位】：安徽理工大学
【学位级别】：硕士
【学位授予年份】：2008
【分类号】：R371;R735.34

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