Aberrant Splicing of Hugl-1 Is Associated with Hepatocellular Carcinoma Progression
Aberrant Splicing of Hugl-1 Is Associated with Hepatocellular Carcinoma Progression
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Hugl-1 的异常剪接与肝细胞癌进展相关
DOI：
10.1158/1078-0432.ccr-08-2078
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发表时间：
2009-05-15
影响因子：
11.5
通讯作者：
Chen, Zhengjun
中科院分区：
文献类型：
--
作者：
Lu, Xuefeng;Feng, Xiujing;Chen, Zhengjun
目的：果蝇巨幼虫是一种细胞极性调节因子和肿瘤抑制因子。它的进化保守性意味着其人类同源物Hugl-1的肿瘤抑制作用。本研究的目的是描述Hugl-1的特征，并确定Hugl-1改变在肝细胞癌（HCC）中的临床意义。试验设计：采用逆转录-PCR和序列分析方法对80例肝癌标本和5株肝癌细胞系的Hugl-1基因进行了序列分析。Western blot检测Hugl-1的表达。通过3-（4，5-二甲基噻唑-2-基）-2，5-二苯基四氮唑溴化试验、伤口愈合试验、Boyden小室试验和致瘤性试验检测Hugl-1及其异常变体的生物学活性。结果如下：在32.5%（26/80）的标本和20.0%（1/5）的HCC细胞系中，鉴定出23种独特的异常Hugl-1转录物，其中大部分是由于跳过部分和/或整个外显子或插入内含子序列。这些异常Hugl-1转录物中的大多数编码缺乏一个或多个保守WD-40重复基序的截短蛋白。两个截断Hugl-1蛋白被发现专门在肝癌组织。异常Hugl-1转录本（78.3%，23个中的20个）在其缺失区域的侧翼具有短的“直接重复”序列。Hugl-1的异常表达与HCC的分化程度低、肿瘤体积大密切相关。两种代表性肝癌衍生的异常Hugl-1变体的过表达促进了肝癌细胞在裸鼠中的迁移、侵袭和致瘤性。结论：我们提供的第一个证据表明，Hugl-1 mRNA经常突变的异常剪接专门在肝癌，这可能涉及肝癌的进展。
Purpose: Lethal giant larvae functions as a cell polarity regulator and a tumor suppressor in Drosophila. Its evolutionary conservation implies a tumor suppressor role for its human homologue, Hugl-1. The aims of this study were to characterize Hugl-1 and to determine the clinical significance of Hugl-1 alterations in hepatocellular carcinoma (HCC). Experimental Design: Sequence alterations of Hugl-1 from 80 HCC specimens and 5 HCC cell lines were characterized by reverse transcription-PCR and sequence analysis. Western blot was used for determining Hugl-1 expression. The biological activities of Hugl-1 and its aberrant variants were examined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, wound healing assay, Boyden chamber assay, and tumorigenicity assay. Results: In 32.5% (26 of 80) of the specimens and 20.0% (one of five) of HCC cell lines, 23 unique aberrant Hugl-1 transcripts were identified, most of which resulted from skipping part of and/or entire exon or insertion of intron sequences. The majority of these aberrant Hugl-1 transcripts encoded truncated proteins lacking one or more conserved WD-40 repeat motifs. Two truncated Hugl-1 proteins were found exclusively in HCC tissues. Aberrant Hugl-1 transcripts (78.3%, 20 of 23) had a short “direct repeat” sequence flanking their deleted regions. The abnormal Hugl-1 was significantly correlated with poor differentiation and large tumor size of HCC. Overexpression of two representative HCC-derived aberrant Hugl-1 variants promoted HCC cell migration, invasion, and tumorigenicity in nude mice. Conclusions: We provide the first evidence that Hugl-1 mRNA is frequently mutated by aberrant splicing exclusively in HCC, which may be involved in HCC progression.