Okamoto M, Makino M, Yamada K, Nakade K, Yuasa S, Baba M
Division of Human Retroviruses, Faculty of Medicine, Kagoshima University 8-35-1, Japan.
Antiviral Res. 1996 Jun;31(1-2):69-77. doi: 10.1016/0166-3542(96)00946-1.
We have investigated viral breakthrough during a long-term culture of HIV-1-infected cells with the non-nucleoside reverse transcriptase inhibitors (NNRTIs) 6-benzyl-1-ethoxymethyl-5-isopropyluracil (MKC-442), nevirapine and loviride (alpha-APA). When the compounds were examined for their inhibitory effects on HIV-1 (HE strain) replication in MT-4 cells on day 4 after virus infection, the 50% effective concentrations (EC50) of MKC-442, nevirapine and loviride were 9.4, 98 and 21 nM, respectively. After a 48-day culture period, MKC-442, nevirapine and loviride completely inhibited viral breakthrough at concentrations of 1, 5 and 1 microM, respectively. These concentrations were 50-100-fold higher than their EC50 values. When the cells were treated with either MKC-442 (0.04 and 0.2 microM), nevirapine (0.2 and 1 microM) or loviride (0.04 and 0.2 microM) in combination with AZT (0.005 microM), only the combination of 0.2 microM MKC-442 with 0.005 microM AZT could completely inhibit the breakthrough of HIV-1 after a 68-day culture period. Polymerase chain reaction (PCR) analysis revealed that no proviral DNA was detected in the cells treated with this combination. Except for two combinations (0.04 microM MKC-442 + 0.005 microM AZT and 0.04 microM loviride + 0.005 microM AZT), all of the viruses isolated during combination treatments had various amino acid mutations in their reverse transcriptase (RT). These results indicate that the combination treatment with a relatively high dose of MKC-442 and a low dose of AZT may have potential to suppress the emergence of drug resistance during a long-term treatment in vivo and should be further pursued in HIV-1-infected patients.
我们研究了在非核苷类逆转录酶抑制剂（NNRTIs）6-苄基-1-乙氧基甲基-5-异丙基尿嘧啶（MKC-442）、奈韦拉平和洛维地（α-APA）存在的情况下，HIV-1感染细胞长期培养过程中的病毒突破情况。当在病毒感染后第4天检测这些化合物对MT-4细胞中HIV-1（HE株）复制的抑制作用时，MKC-442、奈韦拉平和洛维地的50%有效浓度（EC50）分别为9.4、98和21 nM。经过48天的培养期后，MKC-442、奈韦拉平和洛维地分别在1、5和1 μM的浓度下完全抑制了病毒突破。这些浓度比它们的EC50值高50至100倍。当细胞用MKC-442（0.04和0.2 μM）、奈韦拉平（0.2和1 μM）或洛维地（0.04和0.2 μM）与齐多夫定（AZT，0.005 μM）联合处理时，只有0.2 μM MKC-442与0.005 μM AZT的组合在68天培养期后能完全抑制HIV-1的突破。聚合酶链反应（PCR）分析显示，用该组合处理的细胞中未检测到前病毒DNA。除了两种组合（0.04 μM MKC-442 + 0.005 μM AZT和0.04 μM洛维地 + 0.005 μM AZT）外，联合处理期间分离出的所有病毒在其逆转录酶（RT）中都有各种氨基酸突变。这些结果表明，相对高剂量的MKC-442与低剂量的AZT联合治疗可能有潜力在体内长期治疗期间抑制耐药性的出现，应在HIV-1感染患者中进一步研究。
