肝螺杆菌对肝癌细胞侵袭能力的影响及其可能分子机制

Molecular mechanism study of the effects of Helicobacter hepaticus on human hepatoma cell invasion

目的探讨肝螺杆菌(H.hepaticus)对肝癌细胞侵袭能力的影响及其可能分子机制。方法采用人肝癌细胞株HEPG2和HCCLM3作为研究对象,用Transwell实验检测H.hepaticus刺激肝癌细胞后侵袭细胞的数量;用Western Blot方法和荧光定量PCR分析经H.hepaticus刺激后,HEPG2和HCCLM3细胞内Toll样受体4(TLR4)及其下游髓样分化因子88(My D88)、Toll样受体相关干扰素活化子(TRIF)表达的变化;用si RNA干扰方法下调TLR4或My D88在HEPG2和HCCLM3细胞中的表达水平,再检测其经H.hepaticus刺激后的侵袭能力。结果 H.hepaticus刺激HEPG2和HCCLM3后,肝癌细胞的侵袭能力增加,可显著增加细胞中TLR4及My D88的表达,不影响TRIF的表达,在几乎不表达TLR4或My D88的肝癌细胞中,H.hepaticus不能增强肝癌细胞侵袭能力,此时肝癌细胞的侵袭能力下降。结论 H.hepaticus能增强肝癌细胞侵袭能力并且是依赖TLR4/My D88信号通路而实现的。

Objective To investigate the effect of H.hepaticus on liver cancer cell invasive ability and its possible molecular mechanisms. Methods Using human liver cancer cell lines HEPG2 and HCCLM3 as the research object, we treated them with H.hepaticus, checked the number of invasive cells by transwell invasion assay in vitro; then through Western blot and real time PCR, we examined the expression levels of TLR4, myeloid differentiation factor 88（MyD88）, and TIR-domain-containing adaptor-inducing interferon-[3（TR1F）; last, we tested the cancer cell invasive ability after knocking down TLR4 or MyD88 in HEPG2 and HCCLM3 cells treated with H.hepaticus. Results The invasive ability of HEPG2 and HCCLM3 cells was increased after H.hepaticus stimulation. H.hepaticus could significantly increase the expression of TLR4 and MyD88 in liver cancer cells, but did not affect the expression of TRIF. Since there was almost no expression of TLR4 or MyD88 in liver cancer cells, H.hepaticus could not enhance the invasive ability of them. Conclusion H.hep- aticus can enhance the invasive ability of liver cancer cells which is dependent on the TLR4/MyD88 signaling pathway.