Hsp90 inhibitors to combat antifungal drug resistance.

描述(申请人提供)：真菌感染仍然是艾滋病毒感染者发病和死亡的主要原因。许多对三类抗真菌药物耐药的新兴真菌病原体正在变得越来越常见，并与更高的死亡率有关。抗击耐药真菌病原体应该是当务之急。由于许多非常重要的原因，Hsp90的抑制已经成为一个真正的抗真菌靶点。这些包括IF提高现有抗真菌药物的疗效，阻止耐药性的出现，对广泛的真菌病原体起作用，提高存活率，并在减弱真菌毒力方面发挥重要作用。真菌和哺乳动物Hsp90具有相同的结构和功能，这一事实阻碍了Hsp90真菌抑制剂的开发。因此，已知的Hsp90抑制剂，如格尔达那霉素，可诱导热休克反应，Hsp90、Hsp70和其他辅助伴侣蛋白的过度表达。这种反应既是抗凋亡的，又是存活的，因此潜在地限制了抑制剂作为抗真菌药物的有效性。挑战是找到对真菌Hsp90具有选择性的Hsp90抑制剂。我们发现了两种真菌化合物，它们是念珠菌Hsp90相对于哺乳动物Hsp90的10倍选择性抑制剂。具有这种活性的化合物还没有报道过。使用LifePharms的26,000个担子菌和子囊菌(蘑菇)样本的天然产物库对这些化合物进行筛选，包括几乎所有在美国大陆发现的物种。这项赠款提案的目标如下：1)以分离每个活性化合物2。)鉴定和消除先导化合物3.)为了确定我们的化合物对哺乳动物和真菌细胞中应激标记(Hsp90和Hsp70)的影响。确定我们的抑制剂是否直接与真菌和哺乳动物Hsp90分子上的ATP结合位点相互作用。)确定我们的化合物对临床上重要的真菌物种和6.)以筛选额外的5,000种提取物，以寻找额外的真菌特异性Hsp90抑制剂。目标5的工作将由圣安东尼奥的德克萨斯大学健康科学中心执行。 公共卫生相关性：真菌感染仍然是艾滋病毒感染患者发病和死亡的主要原因。从天然产品中发现了抗真菌化合物。在圣安东尼奥的德克萨斯大学健康科学中心的抗真菌敏感性测试实验室和传染病部门的合作下，我们已经确定了能够恢复先前耐药的念珠菌菌株氟康唑毒性的天然产品。

DESCRIPTION (provided by applicant): Fungal infections continue to be a major cause of morbidity and mortality among HIV-infected patients. Many of the emerging fungal pathogens that are resistant to the three classes of antifungal agents for AID-s-related infections are becoming more common and are associated with higher rates of mortality. Combating drug resistant fungal pathogens should be a top priority. The inhibition of Hsp90 has emerged as a bona fide antifungal target for a number of very important reasons. These include that if increases the efficacy of existing antifungal medications, blocks the emergence of drug resistance, works against a broad spectrum of fungal pathogens, increases survival rates, and pays an important role in attenuating fungal virulence. The development of a Hsp90 fungal inhibitor has been hampered by the fact that fungal and mammalian Hsp90 share structural homology and function. As a result, known Hsp90 inhibitors, such as geldanamycin, induce the heat shock response, an overexpression of Hsp90, Hsp70, and other co-chaperones. This response is both anti-apoptotic and prosurvival, thereby potentially limiting the inhibitors effectiveness as antifungal agents. The challenge is to find inhibitors of Hsp90 that are selective for fungal Hsp90. We have discovered two fungal compounds that are 10X selective inhibitors of Candida Hsp90 relative to mammalian Hsp90. No compounds with this activity have ever been reported. These compounds were screened for using LifePharms' natural product library of 26,000 samples of basidiomycetes and ascomycetes (mushrooms), including nearly every species found in continental United States. The goals of this grant proposal are the following: 1.) to isolate each active compound 2.) to identify and dereplicated lead compounds 3.) to determine the effect of our compounds on stress markers (Hsp90 and Hsp70) in both mammalian and fungal cells 4.) to determine whether our inhibitors interact directly with the ATP binding site on the fungal and mammalian Hsp90 molecule 5.) to determine the in vitro activity and potency of our compounds against panels of clinically important fungal species and 6.) to screen an additional 5,000 extracts for additional fungal-specific Hsp90 inhibitors. The work for goal 5 will be performed by University of Texas Health Science Center at San Antonio. PUBLIC HEALTH RELEVANCE: Fungal infections continue to be a major cause of morbidity and mortality among HIV-infected patients. Antifungal compounds have been discovered from natural products. In collaboration with the Antifungal Susceptibility Testing Laboratory and Division of Infectious Diseases at the University of Texas Health Science Center at San Antonio, we have identified natural products that restore fluconazole toxicity to previously resistant Candida strains.