Systems and carcinogenic impact assessment of topical microbicides on human mucosa

 说明(申请人提供)：几种抗逆转录病毒药物正在作为预防艾滋病毒性传播的局部杀微生物剂进行测试。由于有效的艾滋病毒预防需要健康人频繁使用局部抗逆转录病毒药物，因此这种使用必须是安全的。然而，最近在MTN-007试验中进行的1%替诺福韦凝胶的体内综合评估中，我们发现它对直肠粘膜的基因表达有深远的影响，表明肠道免疫和自我修复动态平衡发生了重要变化。当我们用人类原代阴道上皮细胞跟踪这些结果时，我们发现了非常相似的变化。这些变化，特别是线粒体功能的显著损害和致癌的前景，有可能禁止使用替诺福韦，并可能禁止使用相同DNA链终止剂类别的其他药物作为局部杀菌剂。因此，有必要立即广泛地扩大这些发现，以证实替诺福韦对粘膜的副作用，确定围手术期使用是否比日常使用更安全，并比较其对体内直肠和阴道粘膜的影响。在这项提案的目标1中，我们将使用系统生物学方法在两个试验中解决这些问题，使用直肠和阴道组织标本测试1%替诺福韦凝胶MTN-014和MTN-017。除了我们的数据中间接暗示替诺福韦可以增加粘膜中的肿瘤过程外，大量数据已经证明，DNA链终止剂，如替诺福韦和叠氮胸苷，是致癌和突变的，并具有剂量依赖关系。由于这种作用的潜在严重性，以及局部应用后在粘膜组织中获得的高浓度活性药物(&gt；2比口服剂量高出2个对数)，我们在目标2中建议直接研究外用替诺福韦的粘膜致癌作用，并确定是否非DNA链终止剂如达匹韦林可能是更安全的替代品。我们提出了创新的方法，旨在克服传统的啮齿动物致癌模型的局限性，纳入人类原代粘膜上皮细胞，并包括评估人乳头瘤病毒(HPV)作为替诺福韦诱导的致癌的辅助因素。这些研究将有助于确定像替诺福韦这样的药物作为局部预防药物与像达匹韦林这样的非DNA链终止剂相比的相对适宜性，并为评估候选杀微生物剂的粘膜安全性提供新的工具，包括致癌的可能性。如果我们的研究证实DNA链终止剂药物对于粘膜应用来说风险太大，我们希望能找到像达匹韦林这样的药物作为有效和更安全的替代品。

 DESCRIPTION (provided by applicant): Several antiretroviral drugs are being tested as topical microbicides for the prevention of sexual HIV transmission. Because effective HIV prophylaxis would entail frequent use of topical antiretroviral drugs by healthy individuals, such use would need to be safe. However, in a recent comprehensive assessment of 1% tenofovir gel in vivo, conducted in the MTN-007 trial, we uncovered that it had profound effects on gene expression in the rectal mucosa, suggesting important changes in gut immune and self-repair homeostasis. When we followed up on these results using human primary vaginal epithelial cells, we found very similar changes. These changes, in particular pronounced impairment of mitochondrial function and the prospect of carcinogenicity, have the potential to contraindicate the use of tenofovir, and potentially of other drugs of the same DNA chain terminator class, as a topical microbicide. It is therefore imperative to extensively and immediately expand on these findings in order to corroborate tenofovir's side effects on the mucosa, to determine whether pericoital use is safer than daily use, and to compare its effects on the rectal and vaginal mucosa in vivo. In Aim 1 of this proposal we will address these issues using systems biology approaches in two trials testing 1% tenofovir gel, MTN-014 and MTN-017, using rectal and vaginal tissue specimens. Besides indirect suggestions in our data that tenofovir could increase neoplastic processes in the mucosa, a large body of data has demonstrated that DNA chain terminator drugs, like tenofovir and azidothymidine, are carcinogenic and mutagenic in a dose-dependent manner. Because of the potential gravity of this effect and the high concentrations of active drug achieved in mucosal tissues after topical application (>2 logs higher than achieved by oral dosing), we propose in Aim 2 to directly investigate the mucosal carcinogenicity of topical tenofovir and to determine whether non-DNA chain terminators like dapivirine might be safer alternatives. We propose innovative approaches designed to overcome the limitations of traditional rodent carcinogenicity models, incorporate human primary mucosal epithelial cells, and include an assessment of human papilloma virus (HPV) as a co-factor in tenofovir-induced carcinogenesis. These studies will help determine the relative suitability of drugs like tenofovir as topical prevention agents in comparison to non-DNA chain terminators like dapivirine, and provide novel tools for the assessment of the mucosal safety profile of candidate microbicide drugs, including the likelihood of carcinogenicity. Should our study confirm that DNA chain terminator drugs are too risky for mucosal application, it is hoped that we will find drugs like dapivirine to be effective and safer alternatives.