University Bordeaux, Physiopathologie du cancer du foie, U1053, F-33000 Bordeaux, France.
Hepatology. 2013 Jan;57(1):195-204. doi: 10.1002/hep.25994.
Hepatocellular carcinoma (HCC) is the major primary liver cancer. Glypican-3 (GPC3), one of the most abnormally expressed genes in HCC, participates in liver carcinogenesis. Based on data showing that GPC3 expression is posttranscriptionally altered in HCC cells compared to primary hepatocytes, we investigated the implication of microRNAs (miRNAs) in GPC3 overexpression and HCC. To identify GPC3-regulating miRNAs, we developed a dual-fluorescence FunREG (functional, integrated, and quantitative method to measure posttranscriptional regulations) system that allowed us to screen a library of 876 individual miRNAs. Expression of candidate miRNAs and that of GPC3 messenger RNA (mRNA) was measured in 21 nontumoral liver and 112 HCC samples. We then characterized the phenotypic consequences of modulating expression of one candidate miRNA in HuH7 cells and deciphered the molecular mechanism by which this miRNA controls the posttranscriptional regulation of GPC3. We identified five miRNAs targeting GPC3 3'-untranslated region (UTR) and regulating its expression about the 876 tested. Whereas miR-96 and its paralog miR-1271 repressed GPC3 expression, miR-129-1-3p, miR-1291, and miR-1303 had an inducible effect. We report that miR-1271 expression is down-regulated in HCC tumor samples and inversely correlates with GPC3 mRNA expression in a particular subgroup of HCC. We also report that miR-1271 inhibits the growth of HCC cells in a GPC3-dependent manner and induces cell death.
Using a functional screen, we found that miR-96, miR-129-1-3p, miR-1271, miR-1291, and miR-1303 differentially control GPC3 expression in HCC cells. In a subgroup of HCC, the up-regulation of GPC3 was associated with a concomitant down-regulation of its repressor miR-1271. Therefore, we propose that GPC3 overexpression and its associated oncogenic effects are linked to the down-regulation of miR-1271 in HCC.
肝细胞癌（HCC）是原发性肝癌的主要类型。磷脂酰聚糖蛋白-3（GPC3）是 HCC 中异常表达最严重的基因之一，参与肝癌的发生。基于 HCC 细胞中 GPC3 表达较原代肝细胞发生转录后改变的研究数据，我们研究了 microRNAs（miRNAs）在 GPC3 过表达和 HCC 中的作用。为了鉴定 GPC3 调控的 miRNAs，我们开发了一种双荧光 FunREG（功能性、综合和定量测量转录后调控的方法）系统，允许我们筛选 876 种单独 miRNAs 的文库。在 21 个非肿瘤性肝脏和 112 个 HCC 样本中测量候选 miRNAs 和 GPC3 信使 RNA（mRNA）的表达。然后，我们在 HuH7 细胞中表征了一种候选 miRNA 表达调节的表型后果，并阐明了该 miRNA 控制 GPC3 转录后调控的分子机制。我们鉴定了 5 个靶向 GPC3 3'-非翻译区（UTR）并调节其表达的 miRNA。miR-96 和其同源物 miR-1271 抑制 GPC3 表达，而 miR-129-1-3p、miR-1291 和 miR-1303 具有诱导作用。我们报告说，miR-1271 在 HCC 肿瘤样本中表达下调，并且在 HCC 的特定亚组中与 GPC3 mRNA 表达呈负相关。我们还报告说，miR-1271 以 GPC3 依赖性方式抑制 HCC 细胞的生长并诱导细胞死亡。
使用功能筛选，我们发现 miR-96、miR-129-1-3p、miR-1271、miR-1291 和 miR-1303 以不同方式控制 HCC 细胞中的 GPC3 表达。在 HCC 的一个亚组中，GPC3 的上调与与其抑制剂 miR-1271 的同时下调相关。因此，我们提出 GPC3 过表达及其相关的致癌作用与 HCC 中 miR-1271 的下调有关。
