Adenosine Kinase Is a Key Determinant for the Anti-HCV Activity of Ribavirin
Adenosine Kinase Is a Key Determinant for the Anti-HCV Activity of Ribavirin
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DOI：
10.1002/hep.26421
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发表时间：
2013-10-01
期刊：
影响因子：
13.5
通讯作者：
Kato, Nobuyuki
中科院分区：
文献类型：
--
作者：
Mori, Kyoko;Hiraoka, Osamu;Kato, Nobuyuki
利巴韦林（RBV）通常与干扰素联合治疗慢性丙型肝炎患者。在具有RBV抗性表型的HuH-7衍生的测定系统OR 6（50%有效浓度[EC 50]：>100 μ M）和最近发现的具有RBV敏感表型的Li 23衍生的测定系统ORL 8（EC 50：8 μ M;临床可达到的浓度）之间，RBV的抗丙型肝炎病毒（HCV）活性存在显著差异。这是因为RBV的抗HCV活性是通过抑制携带HCV RNA的RBV敏感性ORL 8细胞中的肌苷一磷酸脱氢酶介导的。通过使用RBV抗性OR 6细胞和RBV敏感ORL 8细胞的比较分析，我们试图鉴定决定RBV抗HCV活性的宿主因子。我们发现，腺苷激酶（ADK）的表达在ORL 8细胞显着高于RBV耐药的OR 6细胞携带HCV RNA。OR 6细胞中ADK的异位表达使其从RBV抗性表型转变为RBV敏感表型，ADK的抑制消除了RBV的活性。我们发现，ORL 8和OR 6细胞之间ADK表达的差异不是ADK基因启动子区遗传多态性的结果，也不是由microRNA控制机制介导的。我们发现，ADK信使RNA的5'非翻译区（UTR）在ORL 8细胞中比在OR 6细胞中长，并且只有长的5'非翻译区具有内部核糖体进入位点（IRES）活性。最后，我们证明了长5' UTR在原代人肝细胞中作为IRES发挥作用。结论：这些结果表明，ADK作为RBV活性的决定因素，并提供了新的见解差异药物敏感性的分子机制。（肝病学2013;58：1236-1244）
Ribavirin (RBV) is often used in conjunction with interferon-based therapy for patients with chronic hepatitis C. There is a drastic difference in the anti-hepatitis C virus (HCV) activity of RBV between the HuH-7-derived assay system, OR6, possessing the RBV-resistant phenotype (50% effective concentration [EC50]: >100 mu M) and the recently discovered Li23-derived assay system, ORL8, possessing the RBV-sensitive phenotype (EC50: 8 mu M; clinically achievable concentration). This is because the anti-HCV activity of RBV was mediated by the inhibition of inosine monophosphate dehydrogenase in RBV-sensitive ORL8 cells harboring HCV RNA. By means of comparative analyses using RBV-resistant OR6 cells and RBV-sensitive ORL8 cells, we tried to identify host factor(s) determining the anti-HCV activity of RBV. We found that the expression of adenosine kinase (ADK) in ORL8 cells was significantly higher than that in RBV-resistant OR6 cells harboring HCV RNA. Ectopic ADK expression in OR6 cells converted them from an RBV-resistant to an RBV-sensitive phenotype, and inhibition of ADK abolished the activity of RBV. We showed that the differential ADK expression between ORL8 and OR6 cells was not the result of genetic polymorphisms in the ADK gene promoter region and was not mediated by a microRNA control mechanism. We found that the 5' untranslated region (UTR) of ADK messenger RNA in ORL8 cells was longer than that in OR6 cells, and that only a long 5' UTR possessed internal ribosome entry site (IRES) activity. Finally, we demonstrated that the long 5' UTR functioned as an IRES in primary human hepatocytes. Conclusion: These results indicate that ADK acts as a determinant for the activity of RBV and provide new insight into the molecular mechanism underlying differential drug sensitivity. (Hepatology 2013;58:1236-1244)