Characterization of Basigin Isoforms and the Inhibitory Function of Basigin-3 in Human Hepatocellular Carcinoma Proliferation and Invasion
Characterization of Basigin Isoforms and the Inhibitory Function of Basigin-3 in Human Hepatocellular Carcinoma Proliferation and Invasion
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Basigin 亚型的表征及 Basigin-3 对人肝细胞癌增殖和侵袭的抑制作用
DOI：
10.1128/mcb.05160-11
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发表时间：
2011-07-01
影响因子：
5.3
通讯作者：
Chen, Zhi-Nan
中科院分区：
文献类型：
--
作者：
Liao, Cheng-Gong;Kong, Ling-Min;Chen, Zhi-Nan
Basigin有四种亚型，在肝细胞癌（HCC）的侵袭中起重要作用。详细的转录调控和功能的basigin异构体尚未报道，除了在主要的异构体basigin-2的情况下，作为诱导剂的基质金属蛋白酶（MMP）。在这里，我们确定basigin-2，basigin-3和basigin-4是人类细胞系中最丰富的转录变体。GeneRacer PCR和荧光素酶报告基因分析表明，basigin-3和basigin-4是从另一个启动子启动的。Basigin-3和Basigin-4在mRNA水平上广泛表达于各种正常人体组织中，并且与正常组织相比在HCC组织中上调。Western blotting和共聚焦成像显示糖基化basigin-3和basigin-4表达并定位于质膜。然而，在培养的细胞系中，在蛋白质水平上仅检测到天然basigin-3，而没有检测到basigin-4。basigin-3过表达抑制肝癌细胞增殖，MMP诱导，并在体外和体内细胞侵袭。双分子荧光互补分析和核磁共振（NMR）分析表明，basigin-3与basigin-2相互作用，形成异源寡聚体。总之，我们系统地研究了basigin的选择性剪接，发现basigin-3可以抑制HCC的增殖和侵袭，可能是通过与作为内源性抑制剂的basigin-2通过异源寡聚化相互作用。
ABSTRACT Basigin, which has four isoforms, plays an important role in invasion of hepatocellular carcinoma (HCC). Detailed transcriptional regulation and functions of the basigin isoforms have not been reported except in the case of the predominant isoform basigin-2, which act as inducer of matrix metalloproteinases (MMPs). Here we determined that basigin-2, basigin-3, and basigin-4 were the most abundant transcript variants in human cell lines. GeneRacer PCR and luciferase reporter assays showed that basigin-3 and basigin-4 were initiated from an alternative promoter. Basigin-3 and basigin-4 were widely expressed in various normal human tissues at the mRNA level and were upregulated in HCC tissues compared to in normal tissues. Western blotting and confocal imaging showed that glycosylated basigin-3 and basigin-4 were expressed and localized to the plasma membrane. However, in cultured cell lines, only native basigin-3, and not basigin-4, was detected at protein level. Overexpression of basigin-3 inhibited HCC cell proliferation, MMP induction, and cell invasion in vitro and in vivo. Bimolecular fluorescence complementation assays and nuclear magnetic resonance (NMR) analysis indicated that basigin-3 interacted with basigin-2 to form hetero-oligomers. In conclusion, we systematically investigated the alternative splicing of basigin and found that basigin-3 could inhibit HCC proliferation and invasion, probably through interaction with basigin-2 as an endogenous inhibitor via hetero-oligomerization.