Department of Gastroenterology, Ruijin Hospital, Shanghai Jiaotong University School of Medicine, 197 Ruijin Second Road, Shanghai 200025, PR China.
Diabetes Res Clin Pract. 2012 May;96(2):187-95. doi: 10.1016/j.diabres.2011.12.028. Epub 2012 Jan 14.
To investigate the effect of metformin on the expression profiles of microRNAs in human pancreatic cancer cells.
MicroRNAs real-time PCR Array was applied to investigate differentially expressed miRNAs in Sw1990 cells treated with or without metformin. Stem-loop real time RT-PCR was used to confirm the results of the array assay in Sw1990 and Panc-1 cells. The effects of miR-26a on cell growth, apoptosis, invasion and migration abilities were respectively examined by CCK8 assay, Apoptosis assay, Matrigel invasion and migration assay. HMGA1 was proved to be a target of miR-26a by Luciferase reporter assay, Real-time PCR and Western-blotting.
Nine miRNAs were significantly up-regulated in metformin treated cells. Metformin up-regulated the expression of miR-26a, miR-192 and let-7c in a dose-dependent manner. Forced expression of miR-26a significantly inhibited cell proliferation, invasion, migration and increased cell apoptosis, whereas knockdown of miR-26a obtained the opposite effect. Furthermore, we demonstrated that HMGA1, an oncogene, is a direct target of miR-26a. Nude mice xenograft models confirmed that metformin up-regulated the level of miR-26a and surpressed the expression of HMGA1 in vivo.
These observations suggested that modulation of miRNA expression may be an important mechanism underlying the biological effects of metformin.
研究二甲双胍对人胰腺癌细胞中 microRNA 表达谱的影响。
应用 microRNA 实时 PCR 阵列研究二甲双胍处理或未处理的 Sw1990 细胞中差异表达的 microRNAs。采用茎环实时 RT-PCR 法在 Sw1990 和 Panc-1 细胞中验证阵列分析的结果。通过 CCK8 检测、凋亡检测、Matrigel 侵袭和迁移检测分别研究 miR-26a 对细胞生长、凋亡、侵袭和迁移能力的影响。通过荧光素酶报告实验、实时 PCR 和 Western blot 实验证明 HMGA1 是 miR-26a 的靶基因。
在二甲双胍处理的细胞中，有 9 个 microRNAs 显著上调。二甲双胍呈剂量依赖性地上调 miR-26a、miR-192 和 let-7c 的表达。强制表达 miR-26a 显著抑制细胞增殖、侵袭和迁移，增加细胞凋亡，而敲低 miR-26a 则获得相反的效果。此外，我们证明 HMGA1，一种癌基因，是 miR-26a 的直接靶基因。裸鼠异种移植模型证实，二甲双胍体内上调 miR-26a 的水平并抑制 HMGA1 的表达。
这些观察结果表明，microRNA 表达的调节可能是二甲双胍生物学效应的重要机制。
