Development of a Peptide-Drug Conjugate for Topically Treating the Viral Skin Disease Molluscum Contagiosum

摘要 传染性软骨病是由痘病毒MCV引起的一种高度传染性皮肤病。它 由于缺乏批准的抗病毒药物，仍是一个未得到满足的医疗需求。MC在上显示为病变 身体和脸可以持续几个月到几年才能解决。皮损最常见于儿童 (5%)和免疫功能受损的个人(5%-18%)。感染仅限于表皮皮肤层； 这不是系统性的。传播直接通过人与人之间的接触、自动接种或间接传播 与异类接触。目前的治疗方法可能是痛苦的，会造成疤痕和心理痛苦。没有一个 目前包括一系列物理、化学和药物干预的治疗方法是统一的 接受或FDA批准。为什么没有被批准的治疗MCV的药物被开发出来 因为病毒不能在组织培养中培养出来进行检测。我们现在已经做了四个主要的 突破：首先，我们已经确定了MCV的一个蛋白质靶点(MD4)，它是 复制。MD4蛋白作为连接病毒聚合酶(POL)的加工性因子(PF)发挥作用 到模板以实现DNA的连续合成。第二，我们已经构建了一个MD4- 代理病毒(MD4-VV)，提供了第一个基于细胞的系统来筛选化合物以对抗 感染细胞中的基本MCV靶蛋白(MD4)。第三，我们合成了一种小分子 (7269)，这结合了MD4目标蛋白的一个精确区域，导致它展开，不再 功能。虽然7269可以阻止代理病毒的感染，但我们无法提高其效力或 尽管进行了激烈的药物化学运动，但仍可消除其轻微毒性。第四，我们克服了这个 通过偶联一个肽来产生TriValine-7269，它与MD4结合的效力是 比未结合的7269大6.3倍，没有明显的毒性。自TriValine-7269以来 不改变与MD4靶的直接结合，其增强的效力是由于细胞穿透和/或 稳定性。阻碍进一步药物开发的挑战是Trivaline-7269与 同等或更大效力的类似物，以降低药物开发下一个阶段的风险。我们的目标是 确定效价相同或更高的曲瓦林-7269类似物作为基本备份。目标1将利用 药物化学合成曲瓦林-7269类似物。重点将是改变这两种多肽 和TriValine-7269的连接物部分。7269部分不会被修改，因为它已经 最优化。我们将生产30-40个类似的产品。AIM 2将评估新类似物的抗病毒效力 替代病毒；细胞毒性；阻断体外进行的DNA合成；与MD4靶点结合。 AIM 3将评估与局部用药相关的体外ADME活性的结构不同的类似物 应用包括代谢稳定性、溶解性和细胞通透性。与以下条件相结合： 超过或匹配TriValine-7269将为未来的药物开发提供最低数量的类似物。

ABSTRACT Molluscum contagiosum (MC) is a highly contagious skin disease caused by the poxvirus, MCV. It remains an Unmet Medical Need due to lack of an approved antiviral drug. MC appears as lesions on the body and face that can last months-years before resolving. Lesions occur most frequently in children (5%) and immune compromised individuals (5-18%). The infection is confined to the epidermal skin layers; it is not systemic. Transmission spreads directly from person-person contact, autoinoculation or indirect contact with fomites. Current treatments can be painful, cause scarring, and psychological distress. None of the current treatments that include a range of physical, chemical and medicinal interventions are uniformly accepted or FDA approved. The reason why no approved drug against MCV has been developed is because the virus cannot be grown in tissue culture for testing. We have now made four major breakthroughs: First, we have identified a protein target (mD4) of MCV that is essential for replication. The mD4 protein functions as a processivity factor (PF) that tethers the viral Polymerase (Pol) to the template to enable continuous synthesis of DNA. Second, we have constructed a mD4- surrogate virus (mD4-VV), providing the first cell-based system for screening compounds against an essential MCV target protein (mD4) in infected cells. Third, we have synthesized a small molecule (7269) that that binds a precise region of the mD4 target protein, causing it to unfold and no longer function. While 7269 can block infection by the surrogate virus, we were unable to improve its potency or eliminate its slight toxicity despite an intense medicinal chemistry campaign. Fourth, we overcame this impasse by conjugating a peptide to produce TriValine-7269 that binds the mD4 with a potency that is 6.3-fold greater than that of unconjugated 7269 and has no measurable toxicity. Since TriValine-7269 does not alter direct binding to the mD4 target, its increased potency is due to cellular penetration and/or stability. The challenge that impedes further drug development is that TriValine-7269 has no related analog of equal or greater potency to mitigate risk in the next stages of drug development. The GOAL is to identify analogs of TriValine-7269 of equal or greater potency as essential backups. AIM 1 will utilize medicinal chemistry to synthesize analogs of TriValine-7269. The focus will be to vary both the Peptide and Linker portions of TriValine-7269. The 7269 portion will not be modified since it has already been optimized. We will produce 30-40 analogs. AIM 2 will evaluate new analogs for antiviral potency against the surrogate virus; cytotoxicity; blocking in vitro processive DNA synthesis; binding to the mD4 target. AIM 3 will evaluate structurally distinct analogs for in vitro ADME activities that are relevant for topical application including metabolic stability, solubility and cell permeability. Conjugates with criteria that exceed or match TriValine-7269 will provide the minimum number of analogs for future drug development.