5-氟尿嘧啶通过促进miR-22表达抑制肝癌细胞增殖

5-Fluorouracil suppresses human hepatocellular carcinoma cell growth via promoting miR-22 expression

目的研究5-氟尿嘧啶(5-FU)对miR-22在肝癌细胞中表达的影响及其抑制肝癌细胞增殖的分子机制。方法用Real-time PCR法检测肝细胞癌组织及细胞系中miR-22的表达;用Real-Time PCR法检测经不同浓度5-FU处理的肝癌细胞HepG2和Huh7中miR-22及其初始转录产物pri-miR-22的表达;用miR-22类似物及5-FU处理肝癌细胞HepG2和Huh7,并用Western blot法检测miR-22靶基因HDAC4的表达;设计拯救实验(rescue assay)研究5-FU、miR-22与肝癌细胞增殖的关系。结果 miR-22在肝细胞癌组织及细胞系中表达下调;5-FU可以诱导肝癌细胞系HepG2、Huh7内源性miR-22、pri-miR-22表达水平明显上调(P<0.01);miR-22过表达及5-FU处理可以抑制HepG2、Huh7,HDAC4蛋白表达水平(P<0.01)。结论 5-FU通过调控miR-22介导的HDAC4信号通路发挥抑制肝癌细胞增殖的作用。

Objective To investigate the impact of 5-fluorouracil（ 5-FU） on miR-22 expression in human hepatocellular carcinoma（ HCC） cell lines and to elucidate the molecular mechanism of 5-fluorouracil for HCC chemotherapy. Methods Real-time PCR analysis was conducted to determine the expression levels of miR-22 in HCC tissue specimens and HCC cell lines. The expression of miR-22 and pri-miR-22（ primary miR-22） was evaluated in HepG2 and Huh7 cells with 5-FU treatment by using real-time PCR and we also performed Western blot analysis to detect the protein level of HDAC4 in HCC cells with the same treatment. A rescue assay was employed by using5-FU treatment in combination with miR-22 inhibitor（ Anti-22） to further investigate the correlation among 5-FU,miR-22,and HCC cell growth. Results miR-22 expression depicted a significant downregulation in HCC tissues and cell lines（ P〈0. 01）. 5-FU treatment led to an augment of miR-22 expression in HepG2 and Huh7 cells（ P〈0. 001） and resulted in a decrease of HDAC4 protein levels,which was verified as a direct target of miR-22 in HCC cells（ P〈0. 01）. Conclusions 5-FU has suppressive effect on HCC growth which could be potentially explained by miR-22-mediated HDAC4 axis.