Ichimi Takahiro, Enokida Hideki, Okuno Yasushi, Kunimoto Ryo, Chiyomaru Takeshi, Kawamoto Ken, Kawahara Kazuya, Toki Kazuki, Kawakami Kazumori, Nishiyama Kenryu, Tsujimoto Gozoh, Nakagawa Masayuki, Seki Naohiko
Department of Urology, Graduate School of Medical and Dental Sciences, Kagoshima University, Kagoshima, Japan.
Int J Cancer. 2009 Jul 15;125(2):345-52. doi: 10.1002/ijc.24390.
MicroRNAs (miRNAs) are small noncoding RNAs that negatively regulate protein-coding genes. To identify miRNAs that have a tumor suppressive function in bladder cancer (BC), 156 miRNAs were screened in 14 BCs, 5 normal bladder epithelium (NBE) samples and 3 BC cell lines. We identified a subset of 7 miRNAs (miR-145, miR-30a-3p, miR-133a, miR-133b, miR-195, miR-125b and miR-199a*) that were significantly downregulated in BCs. To confirm these results, 104 BCs and 31 NBEs were subjected to real-time RT-PCR-based experiments, and the expression levels of each miRNA were significantly downregulated in BCs (p < 0.0001 in all). Receiver-operating characteristic curve analysis revealed that the expression levels of these miRNAs had good sensitivity (>70%) and specificity (>75%) to distinguish BC from NBE. Our target search algorithm and gene-expression profiling in BCs (Kawakami et al., Oncol Rep 2006;16:521-31) revealed that Keratin7 (KRT7) mRNA was a common target of the downregulated miRNAs, and the mRNA expression levels of KRT7 were significantly higher in BCs than in NBEs (p = 0.0004). Spearman rank correlation analysis revealed significant inverse correlations between KRT7 mRNA expression and each downregulated miRNA (p < 0.0001 in all). Gain-of-function analysis revealed that KRT7 mRNA was significantly reduced by transfection of 3 miRNAs (miR-30-3p, miR-133a and miR-199a*) in the BC cell line (KK47). In addition, significant decreases in cell growth were observed after transfection of 3 miRNAs and si-KRT7 in KK47, suggesting that miR-30-3p, miR-133a and miR-199a* may have a tumor suppressive function through the mechanism underlying transcriptional repression of KRT7.
微小RNA（miRNA）是一类对蛋白质编码基因起负调控作用的小非编码RNA。为了鉴定在膀胱癌（BC）中具有肿瘤抑制功能的miRNA，我们在14例膀胱癌、5例正常膀胱上皮（NBE）样本和3种膀胱癌细胞系中筛选了156种miRNA。我们鉴定出了7种miRNA组成的一个子集（miR-145、miR-30a-3p、miR-133a、miR-133b、miR-195、miR-125b和miR-199a*），它们在膀胱癌中显著下调。为了证实这些结果，我们对104例膀胱癌和31例正常膀胱上皮样本进行了基于实时逆转录-聚合酶链反应（RT-PCR）的实验，并且每种miRNA的表达水平在膀胱癌中均显著下调（所有p值均<0.0001）。受试者工作特征曲线分析显示，这些miRNA的表达水平对区分膀胱癌和正常膀胱上皮具有良好的敏感性（>70%）和特异性（>75%）。我们的靶标搜索算法以及在膀胱癌中的基因表达谱分析（Kawakami等人，《肿瘤学报道》2006年；16：521 - 31）显示，角蛋白7（KRT7）mRNA是下调的miRNA的一个共同靶标，并且KRT7的mRNA表达水平在膀胱癌中显著高于正常膀胱上皮（p = 0.0004）。Spearman等级相关分析显示KRT7 mRNA表达与每种下调的miRNA之间存在显著的负相关（所有p值均<0.0001）。功能获得分析显示，在膀胱癌细胞系（KK47）中转染3种miRNA（miR-30-3p、miR-133a和miR-***）*可使KRT7 mRNA显著降低。此外，在KK47中转染3种miRNA和si-KRT7后观察到细胞生长显著下降，这表明miR-30-3p、miR-133a和miR-199a可能通过KRT7转录抑制的潜在机制发挥肿瘤抑制功能。 原文中此处miR-199a表述有误，推测应为miR-199a-3p，译文在号处按推测修改后翻译
