目的 研究miR-338-5p/SIRT1相关信号通路在黑树莓花青素化学预防结直肠癌中的作用。方法 小鼠分为健康对照组，氧化偶氮甲烷（AOM）/葡聚糖硫酸钠（DSS）诱导的炎症相关性结直肠癌小鼠模型组，AOM/DSS诱导联合黑树莓花青素处理组。利用miRNA基因芯片筛选差异表达miRNAs，选定miR-338-5p，采用RT-qPCR确认miR-338-5p在小鼠结肠组织及在人结直肠癌细胞株Caco-2、LoVo、HCT-116、HT29、SW480中的mRNA表达，生物信息学软件预测miR-338-5p和SIRT1靶向调节关系。Western blotting检测小鼠结肠组织中SIRT1蛋白及其下游mTOR等信号通路相关蛋白表达。结果 miRNA基因芯片分析发现，与常规饮食的模型小鼠相比，喂食添加黑树莓花青素的模型小鼠结直肠肿瘤组织中miR-338-5p表达量显著减少，进一步研究几种结肠癌细胞系，确认了miR-338-5p表达趋势；黑树莓花青素处理结直肠癌细胞，miR-338-5p的表达能够显著降低。生物信息学预测miR-338-5p和SIRT1存在靶向调节关系。机制研究发现黑树莓花青素可以促进肠上皮细胞SIRT1蛋白的表达，并对其下游mTOR等相关信号通路分子蛋白水平具有调控作用。结论 黑树莓花青素可能通过靶向调控miR-338-5p/SIRT1相关信号通路而发挥对结直肠癌的化学预防作用，进而为结直肠癌提供新的化学预防策略。

Objective To investigate the role of miR-338-5p/SIRT1-related signaling pathway in the treatment of colorectal cancer by the chemopreventive effects of black raspberry (BRB) anthocyanins. Methods Mice were divided into normal healthy control group, AOM/DSS-induced colorectal cancer groups with or without BRB anthocyanin. miRNA microarray was used to investigate differentially expressed miRNAs and RT-qPCR was applied to verify the expression of selected miR-338-5p/SIRT1 in colon tissue of mice and human colorectal cancer cell lines of Caco-2, LoVo, HCT-116, HT29, and SW480. TargetScan and miRanda bioinformatics software was used to predict the targeted regulation relationships between miR-338-5p and SIRT1. The expression of SIRT1 protein in colon tissue of mice and downstream signaling pathway-related proteins were determined by Western blotting. Results miRNA microarray differential analysis demonstrated that the expression of miR-338-5p was significantly reduced in colon tissues of AOM/DSS induced mice fed with BRB anthocyanin. While after 9 weeks administration of BRB anthocyanins, the level of miR-338-5p in AOM/DSS induced mice was decreased. The expression pattern of miR-338-5p was confirmed in the colon tissue and several colon cancer cell lines. Meanwhile, colorectal cancer cells were treated with BRB anthocyanin, miR-338-5p expression was reduced. TargetScan and miRanda predicted that the SIRT1 was one of target genes of miR-338-5p. BRB anthocyanins could promote the expression of SIRT1 protein in intestinal epithelial cells and regulate the protein levels of downstream moleculars including mTOR et al. Conclusion miR-338-5p/SIRT1-related signaling pathway might involve in the chemoprevention effects of BRB anthocyanin on colorectal cancer, which provided a new strategy for chemoprevention of colorectal cancer.

国家自然科学基金项目（81272333，81472821）