Zhu Liye, Gao Jing, Huang Kunlun, Luo Yunbo, Zhang Boyang, Xu Wentao
Laboratory of Food Safety, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing, China, 100083.
Beijing Laboratory for Food Quality and Safety, Beijing, P. R. China.
Sci Rep. 2015 Nov 16;5:16732. doi: 10.1038/srep16732.
Aflatoxin-B1 (AFB1), a hepatocarcinogenic mycotoxin, was demonstrated to induce the high rate of hepatocellular carcinoma (HCC). MicroRNAs (miRNAs) participate in the regulation of several biological processes in HCC. However, the function of miRNAs in AFB1-induced HCC has received a little attention. Here, we applied Illumina deep sequencing technology for high-throughout profiling of microRNAs in HepG2 cells lines after treatment with AFB1. Analysis of the differential expression profile of miRNAs in two libraries, we identified 9 known miRNAs and 1 novel miRNA which exhibited abnormal expression. KEGG analysis indicated that predicted target genes of differentially expressed miRNAs are involved in cancer-related pathways. Down-regulated of Drosha, DGCR8 and Dicer 1 indicated an impairment of miRNA biogenesis in response to AFB1. miR-34a was up-regulated significantly, down-regulating the expression of Wnt/β-catenin signaling pathway by target gene β-catenin. Anti-miR-34a can significantly relieved the down-regulated β-catenin and its downstream genes, c-myc and Cyclin D1, and the S-phase arrest in cell cycle induced by AFB1 can also be relieved. These results suggested that AFB1 might down-regulate Wnt/β-catenin signaling pathway in HepG2 cells by up-regulating miR-34a, which may involve in the mechanism of liver tumorigenesis.
黄曲霉毒素B1（AFB1）是一种具有肝癌致癌性的霉菌毒素，已被证明可诱发高发性肝细胞癌（HCC）。微小RNA（miRNA）参与肝癌中多种生物学过程的调控。然而，miRNA在AFB1诱导的肝癌中的作用鲜受关注。在此，我们应用Illumina深度测序技术对经AFB1处理后的HepG2细胞系中的微小RNA进行高通量分析。通过分析两个文库中miRNA的差异表达谱，我们鉴定出9个已知miRNA和1个新的miRNA，它们均呈现异常表达。KEGG分析表明，差异表达miRNA的预测靶基因参与癌症相关通路。Drosha、DGCR8和Dicer 1的下调表明miRNA生物合成在响应AFB1时受损。miR-34a显著上调，通过靶基因β-连环蛋白下调Wnt/β-连环蛋白信号通路的表达。抗miR-34a可显著缓解AFB1诱导的β-连环蛋白及其下游基因c-myc和细胞周期蛋白D1的下调，同时也可缓解细胞周期中的S期阻滞。这些结果表明，AFB1可能通过上调miR-34a下调HepG2细胞中的Wnt/β-连环蛋白信号通路，这可能参与了肝脏肿瘤发生的机制。
