Sorafenib Inhibits the Shedding of Major Histocompatibility Complex Class I-Related Chain A on Hepatocellular Carcinoma Cells by Down-Regulating a Disintegrin and Metalloproteinase 9
Sorafenib Inhibits the Shedding of Major Histocompatibility Complex Class I-Related Chain A on Hepatocellular Carcinoma Cells by Down-Regulating a Disintegrin and Metalloproteinase 9
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DOI：
10.1002/hep.23456
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发表时间：
2010-04-01
期刊：
影响因子：
13.5
通讯作者：
Hayashi, Norio
中科院分区：
文献类型：
--
作者：
Kohga, Keisuke;Takehara, Tetsuo;Hayashi, Norio
主要组织相容性复合物I类相关链A（云母）的胞外域从肿瘤细胞中脱落，可能是逃避抗肿瘤免疫的重要手段。本研究探讨了去整合素和金属蛋白酶9（ADAM 9）在人肝细胞癌（HCC）中云母脱落中的作用。小干扰RNA介导的ADAM 9敲低（KD）导致HepG 2和PLC/PRF/5细胞表面膜结合的云母表达上调，培养上清液中可溶性云母水平下调。体外实验表明，ADAM 9在云母的Gln 347和Val 348之间的位点被切割。我们构建了云母基因的质粒，其具有突变或缺失的ADAM 9切割位点，以研究ADAM 9蛋白酶的云母脱落的详细机制。结果表明，云母可能在细胞内的ADAM 9识别的切割位点被切割，并进一步在细胞外的ADAM 9非依赖性切割位点被切割，导致产生可溶性云母。免疫组化分析显示，与正常肝组织相比，ADAM 9在人HCC中过表达。自然杀伤（NK）细胞对ADAM 9 KD-HCC细胞的杀伤活性高于对照细胞，这种杀伤活性的增强依赖于云母/B和NK 2组成员D通路。索拉非尼治疗导致肝癌细胞中ADAM 9表达降低，膜结合云母表达增加，可溶性云母水平降低。添加索拉非尼通过增加膜结合云母的表达来增强HCC细胞的NK敏感性。结论：ADAM 9参与了肝癌细胞云母胞外区的脱落，索拉非尼可调节ADAM 9的表达。索拉非尼治疗可能对HCC患者的抗肿瘤免疫有以前未认识到的作用。（《肝脏学》2010年;51：1264-1273）
The ectodomain of major histocompatibility complex class I related chain A (MICA) is shed from tumor cells, and may be an important means of evading antitumor immunity. This study investigated the roles of a disintegrin and metalloproteinase 9 (ADAM9) in the shedding of MICA in human hepatocellular carcinoma (HCC). Small interfering RNA mediated knockdown (KD) of ADAM9 resulted in up-regulation of membrane-bound MICA expression on the HepG2 and PLC/PRF/5 cellular surfaces and down-regulation of soluble MICA levels in their culture supernatant. ADAM9 was cleaved at a site between Gln347 and Val348 of MICA in vitro. We constructed a plasmid of the MICA gene with mutation or deletion of the ADAM9 cleavage site to examine the detailed mechanism of MICA shedding by ADAM9 protease. The results suggested that MICA might be cleaved at the intracellular ADAM9-recognized cleavage site and was further cleaved at the extracellular ADAM9-independent cleavage site in HCC cells, resulting in the production of soluble MICA. Immunohistochemical analysis revealed that ADAM9 was overexpressed in human HCC compared to normal liver tissues. The cytolytic activity of natural killer (NK) cells against ADAM9KD-HCC cells was higher than that against control cells, and the enhancement of this cytotoxicity depended on the MICA/B and NK group 2, member D pathway. Sorafenib treatment resulted in decreased expression of ADAM9, increased expression of membrane-bound MICA expression, and decreased levels of soluble MICA in HCC cells. Adding sorafenib enhanced the NK sensitivity of HCC cells via increased expression of membrane-bound MICA. Conclusion: ADAM9 is involved in MICA ectodomain shedding in HCC cells, and sorafenib can modulate ADAM9 expression. Sorafenib therapy may have a previously unrecognized effect on antitumor immunity in patients with HCC. (HEPATOLOGY 2010;51: 1264-1273.)