Lee Daniel Y, Deng Zhaoqun, Wang Chia-Hui, Yang Burton B
Sunnybrook Health Sciences Centre and Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, ON, Canada.
Proc Natl Acad Sci U S A. 2007 Dec 18;104(51):20350-5. doi: 10.1073/pnas.0706901104. Epub 2007 Dec 11.
MicroRNAs are single-stranded RNA of 18-24 nt expressed endogenously that play important roles in cancer development. Here, we show that expression of miR-378 enhances cell survival, reduces caspase-3 activity, and promotes tumor growth and angiogenesis. Proteomic analysis indicates reduced expression of suppressor of fused (Sufu), a potential target of miR-378, which was confirmed in vitro and in vivo. Expression of a luciferase construct containing the target site in Sufu was repressed when cotransfected with miR-378. Transfection of a Sufu construct reversed the effect of miR-378, suggesting an important role for miR-378 in tumor cell survival. We also discovered that miR-378 targets Fus-1. Expression of luciferase constructs harboring the target sites in Fus-1 was repressed by miR-378. Fus-1 constructs with or without its 3' UTR were also generated. Cotransfection experiments showed that the presence of miR-378 repressed Fus-1 expression. Suppression of Fus-1 expression by siRNA against Fus-1 enhanced cell survival. Transfection of the Fus-1 construct reversed the function of miR-378 in cell survival. Our results suggest that miR-378 transfection enhanced cell survival, tumor growth, and angiogenesis through repression of the expression of two tumor suppressors, Sufu and Fus-1.
微小RNA是内源性表达的18 - 24个核苷酸的单链RNA，在癌症发展中发挥重要作用。在此，我们表明miR - 378的表达增强细胞存活、降低半胱天冬酶 - 3活性，并促进肿瘤生长和血管生成。蛋白质组学分析表明，miR - 378的潜在靶标融合抑制因子（Sufu）表达降低，这在体外和体内均得到证实。当与miR - 378共转染时，含有Sufu中靶位点的荧光素酶构建体的表达受到抑制。转染Sufu构建体可逆转miR - 378的作用，表明miR - 378在肿瘤细胞存活中起重要作用。我们还发现miR - 378靶向Fus - 1。miR - 378抑制含有Fus - 1中靶位点的荧光素酶构建体的表达。还构建了带有或不带有其3'非翻译区的Fus - 1构建体。共转染实验表明，miR - 378的存在抑制Fus - 1表达。针对Fus - 1的小干扰RNA抑制Fus - 1表达可增强细胞存活。转染Fus - 1构建体可逆转miR - 378在细胞存活中的功能。我们的结果表明，miR - 378转染通过抑制两种肿瘤抑制因子Sufu和Fus - 1的表达来增强细胞存活、肿瘤生长和血管生成。
