Small Molecule E6 Inhibitors to Treat Dysplasia Caused by HPV Infections

人乳头瘤病毒(HPV)引起非常常见的皮肤和 粘膜上皮细胞。感染特定的高危HPV基因型会进展到前 称为异型增生的恶性病变，在一段时间内，可最终发展为侵袭性和 转移性上皮性恶性肿瘤。我们的治疗目标是治疗早期感染的 宫颈、生殖器和肛门，在这些进展到侵入性之前，折磨着数百万的女性和男性 癌症。 Kovina治疗公司的策略是通过选择性地靶向E6来消除HPV感染 蛋白质和阻止与其细胞结合伙伴的相互作用。E6对于病毒来说是必要的 基因组复制和维持，并总是在HPV相关的异型增生和 恶性肿瘤。我们对小分子的化学库进行了电子筛选， 将类似于E6与其几个蜂窝合作伙伴的接口。我们的化验结果集中在 E6与泛素连接酶E6AP的蛋白质-蛋白质相互作用 蛋白酶体介导的肿瘤抑制蛋白P53的破坏。使用这个模型，我们 设计和合成的1)与HPV-16 E6结合的化合物和2)配备了“弹头” 与E6AP的HPV-16E6结合口袋中的特定半胱氨酸形成共价键。这个 识别装备有反应弹头的分子的方法，这些反应弹头调解共价和 与半胱氨酸的不可逆结合在几种新的临床可用药物中得到了例证 以前被认为不能下药的蛋白质。我们发现了几种共价结合的化合物 通过这个半胱氨酸残基，阻断E6与E6AP的相互作用，恢复P53功能，诱导 表达HPV-16的细胞死亡。包括X射线结晶学在内的多种生化分析 证明这些抑制剂占据靶向E6口袋，并与半胱氨酸形成单一加合物。 共晶数据引导下的迭代优化设计与合成&GT；80新化合物 化合物，并导致化学类型的活性增加。这项为期一年的第一阶段SBIR 提案计划筛选我们现有的E6抑制剂集合，以确定它们的生物活性 在基于细胞的分析和药代动力学特性中，符合FDA的局部应用指南 探员。我们将开展药物开发研究，包括外用配方和 早期药代动力学和毒理学特征。第一阶段研究的成功将 验证此抗病毒策略，并使我们能够继续申请第二阶段SBIR以执行 支持IND的研究。

Human papillomaviruses (HPV) cause exceedingly common infections of cutaneous and mucosal epithelia. Infection with specific “high risk” HPV genotypes can progress to pre- malignant lesions called dysplasias, which over a period of years, can eventuate in invasive and metastatic epithelial malignancies. Our therapeutic goal is to treat early stage infections of the cervix, genitalia, and anus that afflict millions of women and men before these progress to invasive cancers. Kovina Therapeutics strategy is to eliminate HPV infection by selectively targeting the E6 protein and preventing interactions with its cellular binding partners. E6 is necessary for viral genome replication and maintenance and is always expressed in HPV-associated dysplasia and malignancies. We performed in silico screening of chemical libraries for small molecules that would resemble the interface of E6 with several of its cellular partners. Our assays focused on the protein-protein interaction of E6 with the ubiquitin ligase E6AP, which mediates ubiquitination and proteasome mediated destruction of the tumor suppressor protein p53. Using this model, we designed and synthesized compounds that 1) bind to HPV-16 E6 and 2) are armed with a ‘warhead’ to make a covalent bond with a specific cysteine in HPV-16 E6 binding pocket for E6AP. The approach to identify molecules equipped with reactive warheads that mediate covalent and irreversible binding to cysteine is exemplified in several new clinically available drugs that target proteins previously considered undruggable. We discovered several compounds covalently bound to E6 via this cysteine residue, block E6 interaction with E6AP, restore P53 function, and induce death of HPV-16 expressing cells. Multiple biochemical analyses including X-ray crystallography prove these inhibitors occupy the targeted E6 pocket and form a single adduct with this cysteine. Iterative optimization guided by the co-crystal data enabled design and synthesis of >80 novel compounds and has resulted chemotypes with increased activity. This one-year Phase I SBIR proposal plans to screen our existing E6 inhibitor collection to determine their biological activities in cell-based assays and pharmacokinetic properties that would meet FDA guidelines for a topical agent. We will initiate drug development studies including formulation for topical application and early stage pharmacokinetic and toxicology characterization. The success of Phase I study will validate this antiviral strategy and position us to proceed to apply for a Phase II SBIR to perform IND-enabling studies.