Targeting Regorafenib-Induced Toxicity through Inhibition of Gut Microbial β-Glucuronidases
Targeting Regorafenib-Induced Toxicity through Inhibition of Gut Microbial β-Glucuronidases
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DOI：
10.1021/acschembio.9b00663
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发表时间：
2019-12-01
影响因子：
4
通讯作者：
Redinbo, Matthew R.
中科院分区：
文献类型：
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作者：
Ervin, Samantha M.;Hanley, Ronan P.;Redinbo, Matthew R.
瑞戈非尼（Stivarga）是一种口服小分子激酶抑制剂，用于治疗转移性结直肠癌、肝细胞癌和胃肠道间质瘤。腹泻是最常见的瑞格非尼相关不良反应之一。这种毒性可能是由于胃肠道中的肠道微生物β-葡萄糖醛酸苷酶（GUS）将无活性的瑞戈非尼-葡萄糖醛酸苷重新激活为瑞戈非尼所致。我们试图揭示人肠道GUS酶对瑞戈非尼-葡糖苷酸加工的分子基础，并检测这些酶的潜在抑制作用。使用一组31种独特的肠道微生物GUS酶（来自人类肠道微生物组的279种酶），我们发现只有4种酶能够进行瑞格非尼-葡糖苷酸加工。以晶体结构为指导，我们精确定位了这些赋予瑞戈非尼-葡萄糖醛酸苷加工活性的酶所特有的分子特征。此外，一项初步筛选确定了FDA批准的药物雷洛昔芬作为发现的GUS蛋白再激活瑞格非尼的抑制剂。新型合成雷洛昔芬类似物在体外和离体研究中均表现出改善的效力。综上所述，这些数据确定了瑞格非尼的再活化仅由肠道微生物酶催化，并且这些酶易于靶向抑制。我们的研究结果揭示了瑞格非尼在胃肠道中重新激活的关键分子细节，并提供了一种改善瑞格非尼临床结局的潜在途径。
Regorafenib (Stivarga) is an oral small molecule kinase inhibitor used to treat metastatic colorectal cancer, hepatocellular carcinomas, and gastrointestinal stromal tumors. Diarrhea is one of the most frequently observed adverse reactions associated with regorafenib. This toxicity may arise from the reactivation of the inactive regorafenib-glucuronide to regorafenib by gut microbial beta-glucuronidase (GUS) enzymes in the gastrointestinal tract. We sought to unravel the molecular basis of regorafenib-glucuronide processing by human intestinal GUS enzymes and to examine the potential inhibition of these enzymes. Using a panel of 31 unique gut microbial GUS enzymes derived from the 279 mapped from the human gut microbiome, we found that only four were capable of regorafenib-glucuronide processing. Using crystal structures as a guide, we pinpointed the molecular features unique to these enzymes that confer regorafenib-glucuronide processing activity. Furthermore, a pilot screen identified the FDA-approved drug raloxifene as an inhibitor of regorafenib reactivation by the GUS proteins discovered. Novel synthetic raloxifene analogs exhibited improved potency in both in vitro and ex vivo studies. Taken together, these data establish that regorafenib reactivation is exclusively catalyzed by gut microbial enzymes and that these enzymes are amenable to targeted inhibition. Our results unravel key molecular details of regorafenib reactivation in the GI tract and provide a potential pathway to improve clinical outcomes with regorafenib.