Yang S S, Fliakas-Boltz V, Bader J P, Buckheit R W
Antiviral Evaluation Branch, National Cancer Institute, Bethesda, MD 20892, USA.
Leukemia. 1995 Oct;9 Suppl 1:S75-85.
Current thrust in controlling the Acquired Immune Deficiency Syndrome (AIDS) focuses on antiviral drug development targeting the infection and replication of the human immunodeficiency virus (HIV), the causative agent of AIDS. To date, treatment of AIDS has relied on nucleoside reverse transcriptase inhibitors such as AZT, ddI, and ddC, which eventually become ineffective upon the emergence of resistant mutants bearing specific nucleotide substitutions. The Anti-AIDS Drug Screening Program of the NCI conducts and coordinates a high-capacity semi-robotic in vitro screening of synthetic or natural compounds submitted by academic, research and pharmaceutical institutions world-wide. About 10,000 synthetic compounds are screened annually for anti-HIV activity. Confirmed active agents are subjected to in-depth studies on range and mechanism of action. Emerging from this intense screening activity were a number of potentially promising categories of nonnucleoside reverse transcriptase inhibitors (NNRTI) with structural diversity but strong and reproducible anti-HIV activity. Over 2500 active compounds were evaluated for their inhibitory activity against a panel of both laboratory and clinical virus isolates in the appropriate established cell line or fresh human peripheral blood leukocyte and macrophage preparations. Out of these, 40 agents could be placed structurally in nine categories with an additional 16 unique compounds that share the characteristics of NNRTI. These NNRTIs were shown to inhibit reverse transcriptase enzymatically using homopolymeric or ribosomal RNA as templates. NNRTIs demonstrated similarity in their inhibitory pattern against the HIV-1 laboratory strains IIIB and RF, and an AZT-resistant strain; all were inactive against HIV-2. These compounds were further tested against NNRTI-resistant HIV-1 isolates. NNRTI-resistant HIV-1 isolates were selected and characterized with respect to the change(s) in the viral reverse transcriptase nucleotide sequence. Also, differential cross-resistance or sensitivity patterns to NNRTIs were studied in detail among NNRTI-resistant mutants. When tested in combination with AZT, all of the NNRTI's uniformly exhibited synergistic inhibition of HIV-1, suggesting that combination antiviral therapy of NNRTIs with AZT may be therapeutically promising for AIDS treatment.
当前控制获得性免疫缺陷综合征（艾滋病）的重点在于开发针对人类免疫缺陷病毒（HIV，即艾滋病致病原）感染与复制的抗病毒药物。迄今为止，艾滋病治疗依赖于核苷类逆转录酶抑制剂，如齐多夫定（AZT）、去羟肌苷（ddI）和双脱氧胞苷（ddC），但最终会因携带特定核苷酸替代的耐药突变体出现而失效。美国国立癌症研究所的抗艾滋病药物筛选项目开展并协调对全球学术、研究和制药机构提交的合成或天然化合物进行高容量半自动化体外筛选。每年大约筛选10000种合成化合物以检测其抗HIV活性。确认有活性的药物会针对作用范围和作用机制进行深入研究。从这种高强度筛选活动中涌现出了一些潜在有前景的非核苷类逆转录酶抑制剂（NNRTI）类别，它们结构多样但具有强大且可重复的抗HIV活性。超过2500种活性化合物在合适的既定细胞系或新鲜人外周血白细胞及巨噬细胞制剂中，针对一组实验室和临床病毒分离株评估其抑制活性。其中，40种药物在结构上可归为九类，另有16种独特化合物具有NNRTI的特征。这些NNRTI被证明以同聚体或核糖体RNA为模板，能酶促抑制逆转录酶。NNRTI对HIV-1实验室菌株IIIB和RF以及一株AZT耐药菌株的抑制模式相似；对HIV-2均无活性。这些化合物进一步针对NNRTI耐药的HIV-1分离株进行测试。选择并鉴定了NNRTI耐药的HIV-1分离株，以确定病毒逆转录酶核苷酸序列的变化。此外，还详细研究了NNRTI耐药突变体对NNRTI的交叉耐药或敏感性差异模式。当与AZT联合测试时，所有NNRTI均一致表现出对HIV-1的协同抑制作用，这表明NNRTI与AZT联合抗病毒疗法可能对艾滋病治疗具有治疗前景。
