Hsp90 inhibitors to combat antifungal drug resistance.

描述（由申请人提供）：真菌感染仍然是HIV感染患者发病和死亡的主要原因。许多新出现的真菌病原体对三类抗真菌药物的耐药性越来越普遍，并与较高的死亡率有关。防治耐药真菌病原体应是重中之重。由于许多非常重要的原因，Hsp 90的抑制已经成为真正的抗真菌靶标。这些包括，如果增加现有的抗真菌药物的疗效，阻止耐药性的出现，对广谱真菌病原体的工作，提高生存率，并支付在减弱真菌毒力的重要作用。Hsp 90真菌抑制剂的开发受到真菌和哺乳动物Hsp 90共享结构同源性和功能的事实的阻碍。因此，已知的Hsp 90抑制剂，如格尔德霉素，诱导热休克反应，Hsp 90、Hsp 70和其他辅分子伴侣的过表达。这种反应是抗凋亡和促存活的，从而潜在地限制了抑制剂作为抗真菌剂的有效性。挑战在于找到对真菌Hsp 90具有选择性的Hsp 90抑制剂。我们已经发现了两种真菌化合物，它们是念珠菌Hsp 90相对于哺乳动物Hsp 90的10倍选择性抑制剂。没有报道过具有这种活性的化合物。这些化合物是使用LifePharms的26，000个担子菌和子囊菌（蘑菇）样品的天然产物库筛选的，其中几乎包括在美国大陆发现的所有物种。本基金的目标如下：（1）以分离每种活性化合物2）。以鉴定和去复制先导化合物3.）以确定我们的化合物对哺乳动物和真菌细胞中的应激标志物（Hsp 90和Hsp 70）的影响4）。以确定我们的抑制剂是否与真菌和哺乳动物Hsp 90分子上的ATP结合位点直接相互作用5）。以确定我们的化合物对一组临床上重要的真菌物种的体外活性和效力，以及6.）筛选另外5,000种提取物中的真菌特异性Hsp 90抑制剂。目标5的工作将由位于圣安东尼奥的得克萨斯大学健康科学中心进行。 公共卫生相关性：真菌感染仍然是艾滋病毒感染者发病和死亡的主要原因。抗真菌化合物已从天然产物中发现。我们与圣安东尼奥的德克萨斯大学健康科学中心的抗真菌药敏试验实验室和传染病部门合作，鉴定了恢复氟康唑毒性的天然产物，这些天然产物可使以前耐药的念珠菌菌株恢复毒性。

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.