Mutagenesis of Single/Combined NRTI Drugs in Human Cells

描述(申请人提供)：高效抗逆转录病毒疗法 (HAART)在减少艾滋病毒从母亲传播到 婴儿，但用于孕妇HAART的药物组合构成了 子宫内暴露于核苷类似物的婴儿发生肿瘤的风险 逆转录酶抑制剂(NRTI)。这项建议的目的是 确定暴露于特定环境中所致的核DNA损伤程度 在人类淋巴母细胞(azh-1)中，NRTI单独或联合使用，并 确定人类突变易感性表型的变异性 脐带血淋巴细胞。将进行实验以测量(通过特定的 齐多夫定(AZT)、拉米夫定(3TC)和/或司他夫定的DNA掺入 (D4T)，并测量和表征HPRT的诱变反应和 AZH-1细胞的APRT基因座和脐血细胞的HPRT基因座(使用细胞 克隆分析)在培养中暴露于临床重要的抗逆转录病毒 药物，作为单一的药剂或组合。这项工作是研究的延伸 之前由我们的小组进行的研究的宫内诱变性 围产期婴儿对AZT的暴露。事实证明，一种直接的 AZT掺入DNA的水平与 在人类细胞中特定位置诱导的突变水平。第二, 联合暴露于AZT和第二次NRTI(DDI)可增强AZT-DNA的掺入 体外诱变。第三，单独使用AZT或联合使用NRTI治疗 3TC对接尘婴儿具有明显的遗传毒性和致突变作用 子宫，诱变反应的增加至少持续一年 出生后。数据表明，这一增长是由 这表明个体易感因素可能会影响儿童的 宫内预防导致的DNA损伤和突变水平。AZT 在暴露的小鼠和大鼠中也是一种经胎盘致癌物质。拟议中的工作 将确定具有最低诱变潜力的药物/药物组合， 将启动研究以确定增加的易感性的基础 在接触AZT-3TC的婴儿中的一组突变，并将形成 围产期预防措施定量风险评估的基础 单独的NRTI或NRTI的组合。

DESCRIPTION (provided by applicant): Highly active antiretroviral therapy (HAART) has been effective at reducing the transmission of HIV from mother to infant, but the combinations of drugs used for HAART in pregnant women poses a risk for neoplasia in the infants exposed in utero to nucleoside analogue reverse transcriptase inhibitors (NRTIs). The purpose of this proposal is to determine the extent of nuclear DNA damage induced by exposure to specific NRTI's, alone or in combination, in human lymphoblastoid cells (AZH-1), and to determine the variability in the mutation susceptibility phenotype in human cord blood lymphocytes. Experiments will be performed to measure (by specific RIAs) DNA incorporation of zidovudine (AZT), lamivudine (3TC), and/or stavudine (d4T), and to measure and characterize the mutagenic response at the HPRT and APRT loci of AZH-1cells and the HPRT locus of cord blood cells (using cell cloning assays) exposed in culture to clinically important antiretroviral drugs, as single agents or combinations. This work is an extension of studies previously conducted by our group to investigate the in utero mutagenicity of perinatal exposure of infants to AZT. It was demonstrated that a direct correlation exists between the level of the AZT incorporated into DNA and the levels of mutations induced at specific loci in human cells. Second, co-exposure to AZT and a second NRTI (ddI) potentiates AZT-DNA incorporation and mutation induction in vitro. Third, NRTI therapy using AZT alone or with 3TC induces significant genotoxic and mutagenic effects in infants exposed in utero, and the increases in mutagenic responses persist for at least one year after birth. Data indicate that this increase is driven by a subset of the children, suggesting that individual susceptibility factors may influence the levels of DNA damage and mutation that results from in utero prophylaxis. AZT is also a transplacental carcinogen in exposed mice and rats. The proposed work will identify the drugs/drug combinations with the lowest mutagenic potential, will initiate studies to define the basis for the increased susceptibility to mutagenesis in a subset of AZT-3TC exposed infants, and will form the foundation for quantitative risk assessments of perinatal prophylaxis using individual NRTIs or combinations of NRTIs.