Puppo Margherita, Bucci Gabriele, Rossi Martina, Giovarelli Matteo, Bordo Domenico, Moshiri Arfa, Gorlero Franco, Gherzi Roberto, Briata Paola
Gene Expression Regulation Laboratory, IRCCS AOU San Martino-IST, 16132 Genova, Italy; DIMES Sezione Biochimica-Università di Genova, 16132 Genova, Italy.
Center for Translational Genomics and Bioinformatics, San Raffaele Scientific Institute, 20132 Milano, Italy.
Cell Rep. 2016 Jul 26;16(4):967-978. doi: 10.1016/j.celrep.2016.06.055. Epub 2016 Jul 7.
Epithelial-to-mesenchymal transition (EMT) confers several traits to cancer cells that are required for malignant progression. Here, we report that miR-27b-3p-mediated silencing of the single-strand RNA binding protein KHSRP is required for transforming growth factor β (TGF-β)-induced EMT in mammary gland cells. Sustained KHSRP expression limits TGF-β-dependent induction of EMT factors and cell migration, whereas its knockdown in untreated cells mimics TGF-β-induced EMT. Genome-wide sequencing analyses revealed that KHSRP controls (1) levels of mature miR-192-5p, a microRNA that targets a group of EMT factors, and (2) alternative splicing of a cohort of pre-mRNAs related to cell adhesion and motility including Cd44 and Fgfr2. KHSRP belongs to a ribonucleoprotein complex that includes hnRNPA1, and the two proteins cooperate in promoting epithelial-type exon usage of select pre-mRNAs. Thus, TGF-β-induced KHSRP silencing is central in a pathway leading to gene-expression changes that contribute to the cellular changes linked to EMT.
上皮-间质转化（EMT）赋予癌细胞几种恶性进展所需的特性。在此，我们报告，miR-27b-3p介导的单链RNA结合蛋白KHSRP沉默是转化生长因子β（TGF-β）诱导乳腺细胞发生EMT所必需的。持续的KHSRP表达限制了TGF-β依赖的EMT因子诱导和细胞迁移，而在未处理细胞中敲低该蛋白则模拟了TGF-β诱导的EMT。全基因组测序分析表明，KHSRP控制（1）成熟miR-192-5p的水平，这是一种靶向一组EMT因子的微小RNA，以及（2）与细胞黏附和运动相关的一组前体mRNA（包括Cd44和Fgfr2）的可变剪接。KHSRP属于一种核糖核蛋白复合体，其中包括hnRNPA1，这两种蛋白在促进特定前体mRNA的上皮型外显子使用方面相互协作。因此，TGF-β诱导的KHSRP沉默在导致基因表达变化的途径中起核心作用，这些变化促成了与EMT相关的细胞变化。
