Guangdong Provincial Key Laboratory of Translational Cancer Research of Chinese Medicines, Joint International Research Laboratory of Translational Cancer Research of Chinese Medicines, International Institute for Translational Chinese Medicine, School of Pharmaceutical Sciences, Guangzhou University of Chinese Medicine, Guangzhou, Guangdong, 510006, China.
Department of Pharmacological and Pharmaceutical Sciences, College of Pharmacy, University of Houston, 4349 Martin Luther King Boulevard, Houston, Texas 77204, United States.
Phytomedicine. 2023 Nov;120:155040. doi: 10.1016/j.phymed.2023.155040. Epub 2023 Aug 19.
Irinotecan (CPT-11, Camptosar) is a first-line drug for metastatic colorectal cancer. CPT-11-induced diarrhea, which is closely related to the concentrations of β-glucuronidase (β-GUS) and SN-38 in the gut, largely limits its clinical application.
Herein, Xiao-Chai-Hu-Tang (XCHT), a traditional Chinese formula, was applied to mitigate CPT-11-induced toxicity. This study initially explored the mechanism by which XCHT alleviated diarrhea, especially for β-GUS from the gut microbiota.
First, we examined the levels of the proinflammatory cytokines and the anti-inflammatory cytokines in the intestine. Furthermore, we researched the community abundances of the gut microbiota in the CPT-11 and XCHT-treated mice based on 16S rRNA high-throughput sequencing technology. Meanwhile, the level of SN-38 and the concentrations of β-GUS in intestine were examined. We also resolved the 3D structure of β-GUS from gut microbiota by X-ray crystallography technology. Moreover, we used virtual screening, SPR analysis, and enzyme activity assays to confirm whether the main active ingredients from XCHT could selectively inhibit β-GUS.
In XCHT-treated mice, the levels of the proinflammatory cytokines decreased, the anti-inflammatory cytokines increased, and the community abundances of beneficial Firmicutes and Bacteroidota improved in the gut microbiota. We also found that the concentrations of β-GUS and the level of SN-38, the major ingredient that induces diarrhea in the gut, significantly decreased after coadministration of XCHT with CPT-11 in the intestine. Additionally, we revealed the structural differences of β-GUS from different gut microbiota. Finally, we found that EcGUS had good affinity with baicalein and meanwhile could be selectively inhibited by baicalein from XCHT.
Overall, XCHT could relieve the delayed diarrhea induced by CPT-11 through improving the abundance of beneficial gut microbiota and reduced inflammation. Furthermore, based on the three-dimensional structure, baicalein, especially, could be used as a candidate EcGUS inhibitor to alleviate CPT-11-induced diarrhea.
伊立替康（CPT-11，开普拓）是转移性结直肠癌的一线药物。CPT-11 引起的腹泻与肠道中β-葡萄糖醛酸酶（β-GUS）和 SN-38 的浓度密切相关，在很大程度上限制了其临床应用。
本文应用小柴胡汤（XCHT）减轻 CPT-11 引起的毒性。本研究初步探讨了 XCHT 缓解腹泻的机制，特别是对肠道微生物群中β-GUS 的作用。
首先，我们检测了肠道中促炎细胞因子和抗炎细胞因子的水平。此外，我们基于 16S rRNA 高通量测序技术研究了 CPT-11 和 XCHT 处理小鼠的肠道微生物群的群落丰度。同时，检测了 SN-38 和肠道中β-GUS 的浓度。我们还通过 X 射线晶体学技术解析了肠道微生物群中β-GUS 的 3D 结构。此外，我们使用虚拟筛选、SPR 分析和酶活性测定来确认 XCHT 的主要活性成分是否能选择性抑制β-GUS。
在 XCHT 处理的小鼠中，肠道中促炎细胞因子的水平降低，抗炎细胞因子的水平升高，有益的厚壁菌门和拟杆菌门的群落丰度增加。我们还发现，CPT-11 与 XCHT 联合使用后，肠道中β-GUS 的浓度和导致腹泻的主要成分 SN-38 的水平显著降低。此外，我们揭示了不同肠道微生物群中β-GUS 的结构差异。最后，我们发现 EcGUS 与黄芩素具有良好的亲和力，同时黄芩素可被 XCHT 中的黄芩苷选择性抑制。
总的来说，XCHT 通过改善有益肠道微生物群的丰度和减轻炎症来缓解 CPT-11 引起的迟发性腹泻。此外，基于三维结构，黄芩素，特别是，可作为缓解 CPT-11 引起的腹泻的候选 EcGUS 抑制剂。
