Takahashi Kenji, Koyama Kazuya, Ota Yu, Iwamoto Hidetaka, Yamakita Keisuke, Fujii Satoshi, Kitano Yohei
Division of Metabolism and Biosystemic Science, Department of Medicine, Asahikawa Medical University, Asahikawa, Japan.
Department of Laboratory Medicine, Asahikawa Medical University, Asahikawa, Japan.
Front Oncol. 2020 Jun 23;10:1013. doi: 10.3389/fonc.2020.01013. eCollection 2020.
Although non-coding RNAs (ncRNAs) are involved in disease pathogenesis, their contributions to pancreatic ductal adenocarcinoma (PDAC) remain unclear. Recently, the interrelationship between two classes of ncRNA, long non-coding RNAs (lncRNAs), and microRNAs (miRNAs), has been reported to contribute to the epigenetic regulation of gene expression in several diseases including cancers. Moreover, some ncRNAs can be transferred by extracellular vesicles (EVs) from their donor cells to recipient cells. We previously verified that lncRNA HULC is up-regulated in PDAC cells and the intercellular transfer of HULC by EVs can promote PDAC cell invasion and migration through the induction of epithelial-mesenchymal transition (EMT). Therefore, we identified the miRNA that could target HULC and investigated the functional contributions of the miRNA-HULC interaction and EV transfer of miRNA to the EMT pathway in PDAC. Microarray analysis revealed 187 miRNAs that were decreased to <0.87-fold in Panc-1 cells treated with TGF-β compared with the control. Of these, miR-622 was predicted to target HULC directly by bioinformatics analysis. Expression of miR-622 was significantly down-regulated by TGF-β in a panel of PDAC cells. miR-622 overexpression by a miRNA mimic significantly decreased HULC expression, increased E-cadherin expression, and decreased expression of Snail, N-cadherin, and vimentin. Moreover, overexpression of miR-622 significantly reduced cell invasion and migration whereas inhibition of miR-622 increased HULC expression and promoted EMT signaling, invasion, and migration of PDAC cells. Furthermore, incubation with miR-622-overexpressing EVs could transfer miR-622, which significantly elevated miR-622 expression and decreased cell invasion and migration via inhibition of the EMT pathway in recipient PDAC cells. These results provide mechanistic insights into the development of PDAC by demonstrating that miR-622, as a miRNA downregulated by TGF-β, could target HULC and suppress invasion and migration by inhibiting EMT signaling via EV transfer. These observations may identify EV-encapsulated miRNA as a novel therapeutic target for human PDAC.
尽管非编码RNA（ncRNA）参与疾病发病机制，但其在胰腺导管腺癌（PDAC）中的作用仍不清楚。最近，据报道，两类ncRNA，即长链非编码RNA（lncRNA）和微小RNA（miRNA）之间的相互关系，在包括癌症在内的几种疾病中有助于基因表达的表观遗传调控。此外，一些ncRNA可以通过细胞外囊泡（EV）从供体细胞转移到受体细胞。我们之前证实lncRNA HULC在PDAC细胞中上调，并且EV介导的HULC细胞间转移可通过诱导上皮-间质转化（EMT）促进PDAC细胞的侵袭和迁移。因此，我们鉴定了可靶向HULC的miRNA，并研究了miRNA-HULC相互作用以及miRNA的EV转移对PDAC中EMT途径的功能贡献。微阵列分析显示，与对照相比，用TGF-β处理的Panc-1细胞中有187种miRNA降低至<0.87倍。其中，通过生物信息学分析预测miR-622可直接靶向HULC。在一组PDAC细胞中，TGF-β可显著下调miR-622的表达。通过miRNA模拟物过表达miR-622可显著降低HULC表达，增加E-钙黏蛋白表达，并降低Snail、N-钙黏蛋白和波形蛋白的表达。此外，miR-622过表达可显著降低细胞侵袭和迁移，而抑制miR-622则增加HULC表达并促进PDAC细胞的EMT信号传导、侵袭和迁移。此外，与过表达miR-622的EV共孵育可转移miR-622，这可显著提高miR-622表达，并通过抑制受体PDAC细胞中的EMT途径降低细胞侵袭和迁移。这些结果通过证明miR-622作为一种被TGF-β下调的miRNA，可靶向HULC并通过EV转移抑制EMT信号传导来抑制侵袭和迁移，从而为PDAC的发展提供了机制性见解。这些观察结果可能将EV包裹的miRNA鉴定为人类PDAC的新型治疗靶点。
