Discovery and Characterization of FMN-Binding β-Glucuronidases in the Human Gut Microbiome

Pellock, S.J.; Walton, William G.; Ervin, Samantha M.; Torres-Rivera, Dariana; Creekmore, Benjamin C.; Bergan, Grace; Dunn, Zachary D.; Li, Bo; Tripathy, Ashutosh; Redinbo, Matthew R.

doi:10.1016/j.jmb.2019.01.013

Cited by 26 publications

(35 citation statements)

References 17 publications

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“…2A, colored triangles). These classes have been described in detail previously (27)(28)(29)(30); briefly, the Loop 1 and mini-Loop 1 enzymes contain active site-proximal loops that provide favorable interactions for binding smaller substrate-glucuronides. The Loop 1 and mini-Loop 1 enzymes are most frequently associated with the cleavage of small-molecule glucuronides, including drug-glucuronide substrates.…”

Section: Identification Of Estrogen Glucuronide-processing Gut Microbmentioning

confidence: 99%

Section: Structural Rationale For Estrogen Glucuronide-processing Gutmentioning

confidence: 99%

“…Third, we modeled the estrogens within the active site of a dimer from Ruminococcus gnavus 3 GUS (6MVG), an FMNbinding GUS (30). We have previously shown that although these enzymes have an open, planar active site with few aromatic residues, they contain roughly 150 residues that have yet to be resolved in any of the crystal structures we have determined to date (30). However, a model of this domain has been created based on a Loop 2 GUS from Bacteroides uniformis (5UJ6) (27), and this model places the C-terminal domain roughly 15 Å from the active sites of these enzymes.…”

Section: Structural Rationale For Estrogen Glucuronide-processing Gutmentioning

confidence: 99%

“…To date, these compounds are selective for the Loop 1 group of microbial GUS enzymes (28,29). Of the compounds examined, one inhibitor, UNC10201652, is particularly potent, as it contains a piperazine ring that intercepts the catalytic cycle of Loop 1 microbial GUS enzymes and is capable of forming a long-lived inhibitor-glucuronide moiety that remains bound at the enzyme's active site (30). Thus, we chose to examine UNC10201652 (Fig.…”

Section: In Vitro Inhibition Of Gut Microbial Gus Enzymes That Procesmentioning

confidence: 99%

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Gut microbial β-glucuronidases reactivate estrogens as components of the estrobolome that reactivate estrogens

Ervin

Lim

et al. 2019

Journal of Biological Chemistry

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216

157

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Edited by Wolfgang Peti Gut microbial ␤-glucuronidase (GUS) enzymes have been suggested to be involved in the estrobolome, the collection of microbial reactions involving estrogens. Furthermore, bacterial GUS enzymes within the gastrointestinal tract have been postulated to be a contributing factor in hormone-driven cancers. However, to date, there has been no experimental evidence to support these hypotheses. Here we provide the first in vitro analysis of the ability of 35 human gut microbial GUS enzymes to reactivate two distinct estrogen glucuronides, estrone-3-glucuronide and estradiol-17-glucuronide, to estrone and estradiol, respectively. We show that certain members within the Loop 1, mini-Loop 1, and FMN-binding classes of gut microbial GUS enzymes can reactivate estrogens from their inactive glucuronides. We provide molecular details of key interactions that facilitate these catalytic processes and present the structures of two novel human gut microbial GUS enzymes related to the estrobolome. Further, we demonstrate that estrogen reactivation by Loop 1 bacterial GUS enzymes can be inhibited both in purified enzymes and in fecal preparations of mixed murine fecal microbiota. Finally, however, despite these in vitro and ex vivo data, we show that a Loop 1 GUS-specific inhibitor is not capable of reducing the development of tumors in the PyMT mouse model of breast cancer. These findings validate that gut microbial GUS enzymes participate in the estrobolome but also suggest that the estrobolome is a multidimensional set of processes ongoing within the mammalian gastrointestinal tract that likely involves many enzymes, including several distinct types of GUS proteins.

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Section: Identification Of Estrogen Glucuronide-processing Gut Microbmentioning

confidence: 99%

Section: Structural Rationale For Estrogen Glucuronide-processing Gutmentioning

confidence: 99%

Section: Structural Rationale For Estrogen Glucuronide-processing Gutmentioning

confidence: 99%

Section: In Vitro Inhibition Of Gut Microbial Gus Enzymes That Procesmentioning

confidence: 99%

See 2 more Smart Citations

Gut microbial β-glucuronidases reactivate estrogens as components of the estrobolome that reactivate estrogens

Ervin

Lim

et al. 2019

Journal of Biological Chemistry

Self Cite

216

157

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“…Inhibition. The hundreds of unique gut microbial GUS enzymes mapped to date have been categorized into six functionally distinct groups based on active site architecture (13)(14)(15)(16)(17)(18)(19)(20). GUSs are encoded by Bacteroidetes, Firmicutes, and Proteobacteria; among these phyla, Proteobacteria are unique in encoding only Loop 1 (L1) GUS orthologs, which are most efficient with smaller glucuronidated substrates (14).…”

Section: Gus Loop Architecture Dictates Sn38-g Processing Efficiency Andmentioning

confidence: 99%

Targeted inhibition of gut bacterial β-glucuronidase activity enhances anticancer drug efficacy

Bhatt

Pellock

Biernat

et al. 2020

Proc. Natl. Acad. Sci. U.S.A.

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150

104

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Irinotecan treats a range of solid tumors, but its effectiveness is severely limited by gastrointestinal (GI) tract toxicity caused by gut bacterial β-glucuronidase (GUS) enzymes. Targeted bacterial GUS inhibitors have been shown to partially alleviate irinotecan-induced GI tract damage and resultant diarrhea in mice. Here, we unravel the mechanistic basis for GI protection by gut microbial GUS inhibitors using in vivo models. We use in vitro, in fimo, and in vivo models to determine whether GUS inhibition alters the anticancer efficacy of irinotecan. We demonstrate that a single dose of irinotecan increases GI bacterial GUS activity in 1 d and reduces intestinal epithelial cell proliferation in 5 d, both blocked by a single dose of a GUS inhibitor. In a tumor xenograft model, GUS inhibition prevents intestinal toxicity and maintains the antitumor efficacy of irinotecan. Remarkably, GUS inhibitor also effectively blocks the striking irinotecan-induced bloom of Enterobacteriaceae in immunedeficient mice. In a genetically engineered mouse model of cancer, GUS inhibition alleviates gut damage, improves survival, and does not alter gut microbial composition; however, by allowing dose intensification, it dramatically improves irinotecan's effectiveness, reducing tumors to a fraction of that achieved by irinotecan alone, while simultaneously promoting epithelial regeneration. These results indicate that targeted gut microbial enzyme inhibitors can improve cancer chemotherapeutic outcomes by protecting the gut epithelium from microbial dysbiosis and proliferative crypt damage. microbiome | chemotherapy | cancer | gastrointestinal toxicity I rinotecan (CPT-11) is essential for treating colorectal and pancreatic cancers and is frequently administered as a mixture with 5-fluorouracil and/or oxaliplatin. Ongoing clinical trials seek to extend irinotecan to other forms of cancer. However, irinotecan causes both myelosuppression and gastrointestinal (GI) side effects, including mucositis and late-onset diarrhea, which are often dose limiting: 88% of irinotecan patients develop diarrhea, with 30% experiencing acute grade 3 to 4 diarrhea (1-3). This toxicity is frequently refractory to antimotility drugs. Thus, treating irinotecaninduced diarrhea is a significant clinical need (4, 5).The irinotecan prodrug is activated in vivo to SN38, a potent topoisomerase I inhibitor (6) that retards the growth of rapidly proliferating cells in tumors and the intestinal epithelium, which renews every 5 d. SN38 is detoxified through the addition of glucuronic acid (GlcA) to form SN38-G, a compound marked for elimination via the GI tract. Gut commensal bacterial β-glucuronidase (GUS) proteins remove GlcA from SN38-G. Reactivated SN38 inflicts epithelial damage, resulting in bleeding diarrhea and acute weight loss in animal models (7). We reduced irinotecan-induced gut toxicity using inhibitors that selectively, nonlethally, and potently block the actions of gut bacterial GUS enzymes (8,9). The utility of GUS inhibition also extends to drugs be...

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The role of gut microbial β-glucuronidases in carcinogenesis and cancer treatment: a scoping review

Hillege,

Stevens,

Kristen

et al. 2024

J Cancer Res Clin Oncol

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Introduction The human gut microbiota influence critical functions including the metabolism of nutrients, xenobiotics, and drugs. Gut microbial β-glucuronidases (GUS) enzymes facilitate the removal of glucuronic acid from various compounds, potentially affecting anti-cancer drug efficacy and reactivating carcinogens. This review aims to comprehensively analyze and summarize studies on the role of gut microbial GUS in cancer and its interaction with anti-cancer treatments. Its goal is to collate and present insights that are directly relevant to patient care and treatment strategies in oncology. Methods This scoping review followed PRISMA-ScR guidelines and focused on primary research exploring the role of GUS within the gut microbiota related to cancer etiology and anti-cancer treatment. Comprehensive literature searches were conducted in PubMed, Embase, and Web of Science. Results GUS activity was only investigated in colorectal cancer (CRC), revealing increased fecal GUS activity, variations in the gut microbial composition, and GUS-contributing bacterial taxa in CRC patients versus controls. Irinotecan affects gastrointestinal (GI) health by increasing GUS expression and shifting gut microbial composition, particularly by enhancing the presence of GUS-producing bacteria, correlating with irinotecan-induced GI toxicities. GUS inhibitors (GUSi) can mitigate irinotecan's adverse effects, protecting the intestinal barrier and reducing diarrhea. Conclusion To our knowledge, this is the first review to comprehensively analyze and summarize studies on the critical role of gut microbial GUS in cancer and anti-cancer treatment, particularly irinotecan. It underscores the potential of GUSi to reduce side effects and enhance treatment efficacy, highlighting the urgent need for further research to integrate GUS targeting into future anti-cancer treatment strategies.

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Discovery and Characterization of FMN-Binding β-Glucuronidases in the Human Gut Microbiome

Cited by 26 publications

References 17 publications

Gut microbial β-glucuronidases reactivate estrogens as components of the estrobolome that reactivate estrogens

Gut microbial β-glucuronidases reactivate estrogens as components of the estrobolome that reactivate estrogens

Targeted inhibition of gut bacterial β-glucuronidase activity enhances anticancer drug efficacy

The role of gut microbial β-glucuronidases in carcinogenesis and cancer treatment: a scoping review

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