Hsp90 inhibitors to combat antifungal drug resistance.

描述（由申请人提供）：真菌感染仍然是艾滋病毒感染者发病和死亡的主要原因。许多对艾滋病相关感染的三种抗真菌药物具有耐药性的新出现的真菌病原体正变得越来越普遍，并与更高的死亡率相关。与耐药真菌病原体作斗争应成为当务之急。由于一些非常重要的原因，抑制Hsp90已经成为一个真正的抗真菌靶点。其中包括，它提高了现有抗真菌药物的疗效，阻止了耐药性的出现，对广泛的真菌病原体起作用，提高了存活率，并在减轻真菌毒力方面发挥了重要作用。Hsp90真菌抑制剂的开发一直受到真菌和哺乳动物Hsp90具有结构同源性和功能这一事实的阻碍。因此，已知的Hsp90抑制剂，如格尔达霉素，诱导热休克反应，Hsp90、Hsp70和其他共同伴侣蛋白的过表达。这种反应既具有抗凋亡作用，又具有促存活作用，因此可能限制了抑制剂作为抗真菌药物的有效性。挑战在于找到对真菌Hsp90有选择性的Hsp90抑制剂。我们已经发现了两种真菌化合物，它们是念珠菌Hsp90的10倍选择性抑制剂，相对于哺乳动物Hsp90。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26000个担子菌和子囊菌（蘑菇）样本的天然产物库进行筛选的，这些样本几乎包括在美国大陆发现的所有物种。本奖助金提案的目标如下：1)隔离每个活动化合物2。)识别和dereplicated铅化合物3。)来确定我们的压力标记化合物的影响(以及Hsp70)在哺乳动物和真菌细胞4。)来确定我们的抑制剂相互作用直接与ATP结合位点在真菌和哺乳动物一半分子5。)来确定化合物的体外活性和效力与面板临床上重要的真菌物种和6)屏幕上一个额外的5000提取其他真菌特异性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进行。

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.