Expression and functional role of vacuolar H+-ATPase in human hepatocellular carcinoma
Expression and functional role of vacuolar H+-ATPase in human hepatocellular carcinoma
复制标题
人肝细胞癌中液泡H-ATP酶的表达及其功能作用
DOI：
10.1093/carcin/bgs277
复制
发表时间：
2012-12-01
期刊：
影响因子：
4.7
通讯作者：
Tuo, Biguang
中科院分区：
文献类型：
--
作者：
Xu, Jingyu;Xie, Rui;Tuo, Biguang
肿瘤细胞通常存在于缺氧的微环境中，其产生酸性代谢物。为了在这种恶劣的环境中生存，肿瘤细胞必须表现出动态的胞质pH调节系统。研究发现，胞内H-腺苷三磷酸酶（V-ATPase）在调节某些肿瘤的酸性微环境中起重要作用。在本研究中，我们研究了V-ATPase在原发性人肝细胞癌（HCC）中的表达和功能作用。结果表明，与正常肝组织相比，V-ATP酶亚基ATP 6L的mRNA和蛋白表达水平在人原发性肝癌组织中明显增高。免疫组化分析进一步证实了V-ATP酶ATP 6L在人肝癌细胞中的表达增强，并显示V-ATP酶ATP 6L分布于肝癌细胞的胞浆和质膜。免疫荧光和细胞表面蛋白生物素化的结果表明，V-ATP酶ATP 6L明显定位于人肝癌细胞的质膜。巴弗洛霉素A1（Bafilomycin A1）是一种特异性的V-ATP酶抑制剂，它能显著地减缓人肝癌细胞在酸负荷后细胞内pH（pHi）的恢复，并抑制原位异种移植模型中人肝癌的生长。这些结果表明，V-ATP酶在人HCC中上调，并参与调节人HCC细胞的pHi。抑制V-ATP酶可有效抑制肝癌的生长，提示V-ATP酶在肝癌的发生发展中可能起重要作用，靶向V-ATP酶可能是一种有前景的肝癌治疗策略。
Tumor cells often exist in a hypoxic microenvironment, which produces acidic metabolites. To survive in this harsh environment, tumor cells must exhibit a dynamic cytosolic pH regulatory system. Vacuolar H-adenosine triphosphatase (V-ATPase) is considered to play an important role in the regulation of the acidic microenvironment of some tumors. In this study, we made an investigation on the expression and functional role of V-ATPase in native human hepatocellular carcinoma (HCC). The results showed that the messenger RNA and protein expression levels of V-ATPase subunit ATP6L in native human HCC tissues were markedly increased, compared with normal liver tissues. Immunohistochemical analysis further confirmed the enhanced expression of V-ATPase ATP6L in human HCC cells and revealed that V-ATPase ATP6L was distributed in the cytoplasm and plasma membrane of HCC cells. The results from immunofluorescence and biotinylation of cell surface protein showed that V-ATPase ATP6L was conspicuously located in the plasma membrane of human HCC cells. Bafilomycin A1, a specific V-ATPase inhibitor, markedly slowed the intracellular pH (pHi) recovery after acid load in human HCC cells and retarded the growth of human HCC in orthotopic xenograft model. These results demonstrated that V-ATPase is up-regulated in human HCC and involved in the regulation of pHi of human HCC cells. The inhibition of V-ATPase can effectively retard the growth of HCC, indicating that V-ATPase may play an important role in the development and progression of human HCC, and targeting V-ATPase may be a promising therapeutic strategy against human HCC.