Yamada Yasutaka, Arai Takayuki, Kato Mayuko, Kojima Satoko, Sakamoto Shinichi, Komiya Akira, Naya Yukio, Ichikawa Tomohiko, Seki Naohiko
Department of Functional Genomics, Chiba University Graduate School of Medicine Chiba, Japan.
Department of Urology, Chiba University Graduate School of Medicine Chiba, Japan.
Am J Clin Exp Urol. 2019 Feb 18;7(1):11-30. eCollection 2019.
Analyses of our previously determined microRNA (miRNA) expression signature of renal cell carcinoma (RCC) and The Cancer Genome Atlas (TCGA) database revealed that both strands of the pre- (the guide strand) and (the passenger strand)- are closely associated with poor prognosis of RCC patients ( = 0.0411 and = 0.022, respectively). In this study we investigated the functional significance of these miRNAs and identified gene targets involved in RCC pathogenesis. Ectopic expression of these miRNAs significantly attenuated the malignant phenotypes including proliferation, migration and invasion of two RCC cell lines, 786-O and A498. A combination of genome-wide gene expression and database analyses revealed 36 and 34 genes as putative target oncogenes regulated by and , respectively, in RCC cells. Among these targets, expression of aquaporin9 (), a water channel protein, was directly regulated by both and , and high expression levels of were significantly associated with poor prognosis of RCC patients ( = 2.03e-05). Multivariate analysis indicated that expression is an independent prognostic factor for RCC patients. Aberrant AQP9 expression at both the gene and protein level was detected in RCC clinical specimens. siRNA-mediated knockdown of by si- inhibited the malignant phenotypes of RCC cells. Rescue assays of overexpression showed that the axis was closely involved in RCC oncogenesis. The identification of antitumor miRNAs and their targets will contribute to an increased understanding of the molecular pathogenesis of RCC.
对我们之前确定的肾细胞癌（RCC）的微小RNA（miRNA）表达特征以及癌症基因组图谱（TCGA）数据库的分析显示，前体miRNA的两条链（引导链）和（过客链）均与RCC患者的不良预后密切相关（分别为P = 0.0411和P = 0.022）。在本研究中，我们调查了这些miRNA的功能意义，并确定了参与RCC发病机制的基因靶点。这些miRNA的异位表达显著减弱了包括两种RCC细胞系786 - O和A498的增殖、迁移和侵袭在内的恶性表型。全基因组基因表达与数据库分析相结合，分别揭示了36个和34个基因作为RCC细胞中受和调控的假定靶癌基因。在这些靶点中，水通道蛋白水通道蛋白9（AQP9）的表达直接受和调控，且AQP9的高表达水平与RCC患者的不良预后显著相关（P = 2.03e - 05）。多变量分析表明，AQP9表达是RCC患者的独立预后因素。在RCC临床标本中检测到基因和蛋白水平的异常AQP9表达。通过si - AQP9介导的siRNA敲低抑制了RCC细胞的恶性表型。AQP9过表达的挽救实验表明，AQP9轴与RCC肿瘤发生密切相关。抗肿瘤miRNA及其靶点的鉴定将有助于加深对RCC分子发病机制的理解。
