Improving CPT-11 Efficacy Using Structural and Chemical Biology

描述(由申请人提供)：我们正在通过调节胃肠道微生物组的成分来减轻抗癌药物CPT-11的毒性。CPT-11在治疗结直肠癌和胰腺癌中是必不可少的，但剂量限制毒性严重降低了其疗效。这种毒性是由肠道微生物共生体中的一种细菌酶引起的。这种酶-葡萄糖醛酸苷酶从CPT-11‘S关键代谢物中去除失活的葡萄糖醛酸糖，从而使GI中的药物重新激活，导致上皮细胞死亡和急性腹泻。我们假设，选择性、非致命性地抑制微生物的β-葡萄糖醛酸苷酶可以减轻这种副作用。这一假设在前一个项目期间进行的分子到动物的概念验证研究中得到了验证。我们现在将从三个关键方面推进该项目。首先，我们将使用结构生物学和生物化学来表征存在于GI微生物组中的具有活性的β-葡萄糖醛酸苷酶的范围。其次，我们将通过结构和化学生物学创造不同优化的细菌β-葡萄糖醛酸酶抑制剂。第三，使用深度测序和元基因组学，我们将揭示这种方法如何影响胃肠道微生物组的组成和活性。综上所述，我们试图推进一种新的范式-抑制特定的微生物酶以获得治疗收益，而不损害对人类健康至关重要的细菌共生体。

DESCRIPTION (provided by applicant): We are alleviating the toxicity of the anticancer drug CPT-11 by modulating components of the GI microbiome. CPT-11 is essential in treating colorectal and pancreatic cancer, but dose-limiting toxicity severely reduces its efficacy. This toxicity is caused by a bacterial enzyme in enteric microbial symbiotes. The enzyme, ß-glucuronidase, removes the inactivating glucuronic acid sugar from CPT-11's key metabolite, which reactivates the drug in the GI and produces epithelial cell death and acute diarrhea. We hypothesized that the selective, non-lethal inhibition of microbial ß-glucuronidases would alleviate this side effect. This hypothesis tested true in proof-of-concept molecular-to-animal studies conducted in the previous project period. We will now advance the project in three crucial ways. First, we will characterize the range of active ß-glucuronidases present in the GI microbiome using structural biology and biochemistry. Second, we will create differentially optimized bacterial ß-glucuronidase inhibitors via structural and chemical biology. Third, using deep-sequencing and metagenomics, we will unravel how this approach impacts the composition and activity of the GI microbiome. In summary, we seek to advance a novel paradigm - inhibiting specific microbial enzymes for therapeutic gain without harming the bacterial symbiotes essential for human health.