Varnholt Heike, Drebber Uta, Schulze Falko, Wedemeyer Inga, Schirmacher Peter, Dienes Hans-Peter, Odenthal Margarete
Institute for Pathology, University Hospital Cologne, Cologne, Germany.
Hepatology. 2008 Apr;47(4):1223-32. doi: 10.1002/hep.22158.
MicroRNAs are small noncoding RNAs that regulate gene expression by targeting messenger RNAs (mRNAs) through translational repression or RNA degradation. Many fundamental biological processes are modulated by microRNAs, and an important role for microRNAs in carcinogenesis is emerging. Because understanding the pathogenesis of viral-associated hepatocellular carcinomas is important in developing effective means of classification, prognosis, and therapy, we examined the microRNA expression profiles in a large set of 52 human primary liver tumors consisting of premalignant dysplastic liver nodules and hepatocellular carcinomas by quantitative real-time polymerase chain reaction. All patients were infected with hepatitis C, and most had liver cirrhosis. Initially, the accessibility of microRNAs from formalin-fixed paraffin-embedded archival liver tissue by real-time polymerase chain reaction assays was shown. Subsequently, target parenchyma from routinely processed tissue was macrodissected, RNA was extracted, and reverse transcription followed by quantitative real-time polymerase chain reaction was performed. Relative quantification was performed by the 2(-DeltaDeltaCt) method with normal livers as a calibrator. In order to obtain a comprehensive microRNA gene expression profile, 80 microRNAs were examined in a subset of tumors, which yielded 10 up-regulated and 19 down-regulated microRNAs compared to normal liver. Subsequently, five microRNAs (miR-122, miR-100, miR-10a, miR-198, and miR-145) were selected on the basis of the initial results and further examined in an extended tumor sample set of 43 hepatocellular carcinomas and 9 dysplastic nodules. miR-122, miR-100, and miR-10a were overexpressed whereas miR-198 and miR-145 were up to 5-fold down-regulated in hepatic tumors compared to normal liver parenchyma.
A subset of microRNAs are aberrantly expressed in primary liver tumors, serving both as putative tumor suppressors and as oncogenic regulators.
微小RNA是一类小的非编码RNA，通过翻译抑制或RNA降解作用于信使RNA（mRNA）来调控基因表达。许多基本生物学过程都受微小RNA调控，并且微小RNA在肿瘤发生中的重要作用正逐渐显现。由于了解病毒相关性肝细胞癌的发病机制对于开发有效的分类、预后和治疗方法很重要，我们通过定量实时聚合酶链反应检测了一大组由52例人类原发性肝肿瘤（包括癌前发育异常肝结节和肝细胞癌）组成的样本中的微小RNA表达谱。所有患者均感染丙型肝炎，且大多数患有肝硬化。首先，通过实时聚合酶链反应检测显示了从福尔马林固定石蜡包埋存档肝组织中获取微小RNA的可行性。随后，对常规处理组织中的目标实质进行宏观解剖，提取RNA，并进行逆转录及随后的定量实时聚合酶链反应。以正常肝脏为校准物，采用2（-DeltaDeltaCt）法进行相对定量。为了获得全面的微小RNA基因表达谱，在一部分肿瘤样本中检测了80种微小RNA，与正常肝脏相比，其中10种微小RNA上调，19种微小RNA下调。随后，根据初始结果选择了5种微小RNA（miR-122、miR-100、miR-10a、miR-198和miR-145），并在43例肝细胞癌和9例发育异常结节的扩展肿瘤样本组中进一步检测。与正常肝实质相比，miR-122、miR-100和miR-10a在肝肿瘤中过表达，而miR-198和miR-145下调高达5倍。
一部分微小RNA在原发性肝肿瘤中异常表达，既可以作为潜在的肿瘤抑制因子，也可以作为致癌调节因子。
