Department of Urology, the First Hospital of China Medical University, Shenyang, People's Republic of China.
Onco Targets Ther. 2013 Apr 10;6:349-54. doi: 10.2147/OTT.S41343. Print 2013.
BACKGROUNDOBJECTIVE: MicroRNAs (miRNAs) are small noncoding RNAs (ribonucleic acids), approximately 22 nucleotides in length, that function as regulators of gene expression. Dysregulation of miRNAs has been associated with the initiation and progression of oncogenesis in humans. The cell division cycle (CDC)25 phosphatases are important regulators of the cell cycle. Their abnormal expression detected in a number of tumors implies that their dysregulation is involved in malignant transformation.
Using miRNA target prediction software, we found that miR-141 could target the 3' untranslated region (3'UTR) sequence of CDC25B. To shed light on the role of miR-141 in renal cell carcinogenesis, the expression of miR-141 was examined by real-time polymerase chain reaction (RT-PCR) in renal cell carcinoma and normal tissues. The impact of miR-141 re-expression on 769-P cells was analyzed using 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and colony-forming assay. A luciferase reporter assay was applied to prove the functionality of the miR-141 binding site.
miR-141 is significantly downregulated in renal cell carcinoma. miR-141 re-expression suppressed cell growth in 769-P cells. Luciferase expression from a reporter vector containing the CDC25B-3'UTR was decreased when this construct was transfected with miR-141 in 769-P cells. The overexpression of miR-141 suppressed the endogenous CDC25B protein level in 769-P cells.
For the first time, we demonstrated that CDC25B is a direct target of miR-141 in renal cell carcinoma. The transcriptional loss of miR-141 and the resultant increase in CDC25B expression facilitates increased genomic instability at an early stage of renal cell carcinoma development.
背景
microRNAs（miRNAs）是长度约为 22 个核苷酸的小非编码 RNA（核糖核酸），可作为基因表达的调节剂。miRNAs 的失调与人类肿瘤的发生和发展有关。细胞分裂周期（CDC）25 磷酸酶是细胞周期的重要调节剂。它们在许多肿瘤中的异常表达表明其失调参与了恶性转化。
使用 miRNA 靶标预测软件，我们发现 miR-141 可以靶向 CDC25B 的 3'非翻译区（3'UTR）序列。为了阐明 miR-141 在肾细胞癌发生中的作用，通过实时聚合酶链反应（RT-PCR）检测肾细胞癌和正常组织中的 miR-141 表达。使用 3-（4,5-二甲基噻唑-2-基）-2,5-二苯基四氮唑溴盐（MTT）和集落形成测定分析 miR-141 再表达对 769-P 细胞的影响。应用荧光素酶报告基因检测证实了 miR-141 结合位点的功能。
miR-141 在肾细胞癌中显著下调。miR-141 再表达抑制 769-P 细胞的细胞生长。当将包含 CDC25B-3'UTR 的报告载体转染到 769-P 细胞中时，来自荧光素酶表达载体的表达降低。miR-141 的过表达抑制了 769-P 细胞中内源性 CDC25B 蛋白水平。
我们首次证明 CDC25B 是肾细胞癌中 miR-141 的直接靶标。miR-141 的转录丢失和 CDC25B 表达的增加促进了肾细胞癌早期基因组的不稳定性增加。
