Wang Xin, Miyake Hiroshi, Okamoto Mika, Saito Mineki, Fujisawa Jun-Ichi, Tanaka Yuetsu, Izumo Shuji, Baba Masanori
Division of Human Retroviruses, Third Department of Internal Medicine, Faculty of Medicine, Kagoshima University, Kagoshima, Japan.
Mol Pharmacol. 2002 Jun;61(6):1359-65. doi: 10.1124/mol.61.6.1359.
In the search for anti-human T-lymphotropic virus type-I (HTLV-I) compounds, we have evaluated several compounds for their inhibitory effects on HTLV-I replication in cell cultures. Among the test compounds, the fluoroquinolone derivative 7-(3,4-dehydro-4-phenyl-1-piperidinyl)-1,4-dihydro-6-fluoro-1-methyl-8- trifluoromethyl-4-oxoquinoline-3-carboxylic acid (K-37) was found to be a potent and selective inhibitor of HTLV-I replication in persistently infected cells, such as MT-2 and MT-4. When the cells were cultured in the presence of various concentrations of the compound, the 50% effective concentrations of K-37 for HTLV-I p19 antigen production were 0.44 and 0.24 microM in MT-2 and MT-4 cells, respectively. K-37 did not affect the viability and proliferation of these cells at these concentrations, and its 50% cytotoxic concentrations to MT-2 and MT-4 cells were 5.7 and 1.1 microM, respectively. The compound also showed selective inhibition of HTLV-I production in peripheral blood mononuclear cells obtained from patients with HTLV-I-associated myelopathy/tropical spastic paraparesis. Quantitative reverse transcription-polymerase chain reaction analysis revealed that K-37 selectively suppressed viral mRNA synthesis in MT-2 cells in a dose-dependent fashion. Furthermore, K-37 could inhibit the endogenous Tax-induced HTLV-I long terminal repeat (LTR)-driven reporter gene expression in MT-2 cells. Western blot analysis confirmed the reduced expression of Tax in MT-2 cells exposed to K-37. In contrast, when Tax was introduced into cells not infected with HTLV-I with a plasmid under the control of human cytomegalovirus promoter, the compound did not affect Tax-induced HTLV-I LTR-driven reporter gene expression. These results suggest that the inhibition occurred at the level of HTLV-I LTR-driven Tax expression.
在寻找抗人类I型嗜T淋巴细胞病毒（HTLV-I）化合物的过程中，我们评估了几种化合物对细胞培养中HTLV-I复制的抑制作用。在测试的化合物中，氟喹诺酮衍生物7-(3,4-脱氢-4-苯基-1-哌啶基)-1,4-二氢-6-氟-1-甲基-8-三氟甲基-4-氧代喹啉-3-羧酸（K-37）被发现是持续性感染细胞（如MT-2和MT-4）中HTLV-I复制的一种强效且选择性的抑制剂。当细胞在不同浓度的该化合物存在下培养时，K-37对MT-2和MT-4细胞中HTLV-I p19抗原产生的50%有效浓度分别为0.44和0.24微摩尔。在这些浓度下，K-37不影响这些细胞的活力和增殖，其对MT-2和MT-4细胞的50%细胞毒性浓度分别为5.7和1.1微摩尔。该化合物还对外周血单核细胞中HTLV-I的产生显示出选择性抑制作用，这些外周血单核细胞取自患有HTLV-I相关脊髓病/热带痉挛性截瘫的患者。定量逆转录-聚合酶链反应分析表明，K-37以剂量依赖的方式选择性地抑制MT-2细胞中的病毒mRNA合成。此外，K-37可抑制MT-2细胞中内源性Tax诱导的HTLV-I长末端重复序列（LTR）驱动的报告基因表达。蛋白质印迹分析证实，暴露于K-37的MT-2细胞中Tax的表达降低。相反，当用人类巨细胞病毒启动子控制的质粒将Tax导入未感染HTLV-I的细胞时，该化合物不影响Tax诱导的HTLV-I LTR驱动的报告基因表达。这些结果表明，抑制作用发生在HTLV-I LTR驱动的Tax表达水平。
