Preclinical and clinical evidence of the association of colibactinproducing Escherichia coli with anxiety and depression in colon cancer

BACKGROUND The association between the intestinal microbiota and psychiatric disorders is becoming increasingly apparent.The gut microbiota contributes to colorectal carcinogenesis(CRC),as demonstrated with colibactin-producing Escherichia coli(CoPEC).AIM To evaluate the association between CoPEC prevalence and anxiety-and depressive-like behaviors with both preclinical and clinical approaches.METHODS Patients followed after a CRC surgery and for whom the prevalence of CoPEC has been investigated underwent a psychiatric interview.Results were compared according to the CoPEC colonization.In parallel C57BL6/J wild type mice and mice with a CRC susceptibility were chronically infected with a CoPEC strain.Their behavior was assessed using the Elevated Plus Maze test,the Forced Swimming Test and the Behavior recognition system PhenoTyper®.RESULTS In a limited cohort,all patients with CoPEC colonization presented with psychiatric disorders several years before cancer diagnosis,whereas only one patient(17%)without CoPEC did.This result was confirmed in C57BL6/J wildtype mice and in a CRC susceptibility mouse model(adenomatous polyposis colimultiple intestinal neoplasia/+).Mice exhibited a significant increase in anxiety-and depressive-like behaviors after chronic infection with a CoPEC strain.CONCLUSION This finding provides the first evidence that CoPEC infection can induce microbiota-gut-brain axis disturbances in addition to its procarcinogenic properties.

Gut microbiota imbalance and colorectal cancer

The gut microbiota acts as a real organ. The symbiotic interactions between resident micro-organisms and the digestive tract highly contribute to maintain the gut homeostasis. However, alterations to the microbiome caused by environmental changes(e.g., infection, diet and/or lifestyle) can disturb this symbiotic relationship and promote disease, such as inflammatory bowel diseases and cancer. Colorectal cancer is a complex association of tumoral cells, non-neoplastic cells and a large amount of micro-organisms, and the involvement of the microbiota in colorectal carcinogenesis is becoming increasingly clear. Indeed, many changes in the bacterial composition of the gut microbiota have been reported in colorectal cancer, suggesting a major role of dysbiosis in colorectal carcinogenesis. Some bacterial species have been identified and suspected to play a role in colorectal carcinogenesis, such as Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis, Enterococcus faecalis, Clostridium septicum, Fusobacterium spp. and Escherichia coli. The potential pro-carcinogenic effects of these bacteria are now better understood. In this review, we discuss the possible links between the bacterial microbiota and colorectal carcinogenesis, focusing on dysbiosis and the potential pro-carcinogenic properties of bacteria, such as genotoxicity and other virulence factors, inflammation, host defenses modulation, bacterial derived metabolism, oxidative stress and anti-oxidative defenses modulation. We lastly describe how bacterial microbiota modifications could represent novel prognosis markers and/or targets for innovative therapeutic strategies.

Microbial markers in colorectal cancer detection and/or prognosis

Colorectal cancer(CRC) is the second leading cause of cancer worldwide. CRC is still associated with a poor prognosis among patients with advanced disease. On the contrary, due to its slow progression from detectable precancerous lesions, the prognosis for patients with early stages of CRC is encouraging. While most robust methods are invasive and costly, actual patient-friendly screening methods for CRC suffer of lack of sensitivity and specificity. Therefore, the development of sensitive, non-invasive and cost-effective methods for CRC detection and prognosis are necessary for increasing the chances of a cure. Beyond its beneficial functions for the host, increasing evidence suggests that the intestinal microbiota is a key factor associated with carcinogenesis. Many clinical studies have reported a disruption in the gut microbiota balance and an alteration in the faecal metabolome of CRC patients, suggesting the potential use of a microbialbased test as a non-invasive diagnostic and/or prognostic tool for CRC screening. This review aims to discuss the microbial signatures associated with CRC known to date, including dysbiosis and faecal metabolome alterations, andthe potential use of microbial variation markers for noninvasive early diagnosis and/or prognostic assessment of CRC and advanced adenomas. We will finally discuss the possible use of these markers as predicators for treatment response and their limitations.

Colon cancer-associated B2 Escherichia coli colonize gut mucosa and promote cell proliferation

AIM:To provide further insight into the characterization of mucosa-associated Escherichia coli(E.coli)isolated from the colonic mucosa of cancer patients.METHODS:Phylogroups and the presence of cyclomodulin-encoding genes of mucosa-associated E.coli from colon cancer and diverticulosis specimens weredetermined by PCR.Adhesion and invasion experiments were performed with I-407 intestinal epithelial cells using gentamicin protection assay.Carcinoembryonic antigen-related cell adhesion molecule 6(CEACAM6)expression in T84 intestinal epithelial cells was measured by enzyme-linked immunosorbent assay and by Western Blot.Gut colonization,inflammation and procarcinogenic potential were assessed in a chronic infection model using CEABAC10 transgenic mice.Cell proliferation was analyzed by real-time mRNA quantification of PCNA and immunohistochemistry staining of Ki67.RESULTS:Analysis of mucosa-associated E.coli from colon cancer and diverticulosis specimens showed that whatever the origin of the E.coli strains,86%of cyclomodulin-positive E.coli belonged to B2 phylogroup and most harbored polyketide synthase(pks)island,which encodes colibactin,and/or cytotoxic necrotizing factor(cnf)genes.In vitro assays using I-407 intestinal epithelial cells revealed that mucosa-associated B2 E.coli strains were poorly adherent and invasive.However,mucosa-associated B2 E.coli similarly to Crohn’s disease-associated E.coli are able to induce CEACAM6expression in T84 intestinal epithelial cells.In addition,in vivo experiments using a chronic infection model of CEACAM6 expressing mice showed that B2 E.coli strain11G5 isolated from colon cancer is able to highly persist in the gut,and to induce colon inflammation,epithelial damages and cell proliferation.CONCLUSION:In conclusion,these data bring new insights into the ability of E.coli isolated from patients with colon cancer to establish persistent colonization,exacerbate inflammation and trigger carcinogenesis.

Association of colorectal cancer with pathogenic Escherichia coli: Focus on mechanisms using optical imaging

AIM: To investigate the molecular or cellular mechanisms related to the infection of epithelial colonic mucosa by pks-positive Escherichia coli(E. coli) using optical imaging.METHODS: We choose to evaluate the tumor metabolic activity using a fluorodeoxyglucose analogue as 2-deoxyglucosone fluorescent probes and to correlate it with tumoral volume(mm^3). Inflammation measuring myeloperoxidase(MPO) activity and reactive oxygen species production was monitored by a bioluminescent(BLI) inflammation probe and related to histological examination and MPO levels by enzyme-linked immunosorbent assay(ELISA) on tumor specimens. The detection and quantitation of these two signals were validated on a xenograft model of human colon adenocarcinoma epithelial cells(HCT116) in nude mice infected with a pks-positive E. coli. The inflammatory BLI signal was validated intra-digestively in the colitisCEABAC10 DSS models, which mimicked Crohn's disease. RESULTS: Using a 2-deoxyglucosone fluorescent probe, we observed a high and specific HCT116 tumor uptake in correlation with tumoral volume(P = 0.0036). Using the inflammation probe targeting MPO, we detected a rapid systemic elimination and a significant increase of the BLI signal in the pks-positive E. coli-infected HCT116 xenograft group(P < 0.005). ELISA confirmed that MPO levels were significantly higher(1556 ± 313.6 vs 234.6 ± 121.6 ng/m L P = 0.001) in xenografts infected with the pathogenic E. coli strain. Moreover, histological examination of tumor samples confirmed massive infiltration of pks-positive E. coli-infected HCT116 tumors by inflammatory cells compared to the uninfected group. These data showed that infection with the pathogenic E. coli strain enhanced inflammation and ROS production in tumors before tumor growth. Moreover, we demonstrated that the intra-digestive monitoring of inflammation is feasible in a reference colitis murine model(CEABAC10/DSS).CONCLUSION: Using BLI and fluorescence optical imaging, we provided tools to better understand hostpathogen interactions at the early stage of disease, such as inflammatory bowel disease and colorectal cancer.

Impact of time to diagnosis on the occurrence of cardiogenic shock in MIS‑C post‑COVID-19 infection

Background In multisystem inflammatory syndrome in children(MIS-C),diagnostic delay could be associated with severity.This study aims to measure the time to diagnosis in MIS-C,assess its impact on the occurrence of cardiogenic shock,and specify its determinants.Methods A single-center prospective cohort observational study was conducted between May 2020 and July 2022 at a tertiary care hospital.Children meeting the World Health Organization MIS-C criteria were included.A long time to diagnosis was defined as six days or more.Data on time to diagnosis were collected by two independent physicians.The primary outcome was the occurrence of cardiogenic shock.Logistic regression and receiver operating characteristic curve analysis were used for outcomes,and a Cox proportional hazards model was used for determinants.Results Totally 60 children were assessed for inclusion,and 31 were finally analyzed[52%males,median age 8.8(5.7-10.7)years].The median time to diagnosis was 5.3(4.2-6.2)days.In univariable analysis,age above the median,time to diagnosis,high C-reactive protein,and high N-terminal pro-B-type natriuretic peptide(NT-proBNP)were associated with cardiogenic shock[odds ratio(OR)6.13(1.02-36.9),2.79(1.15-6.74),2.08(1.05-4.12),and 1.70(1.04-2.78),respectively].In multivariable analysis,time to diagnosis≥6 days was associated with cardiogenic shock[adjusted OR(aOR)21.2(1.98-227)].Time to diagnosis≥6 days had a sensitivity of 89% and a specificity of 77% in predicting cardiogenic shock;the addition of age>8 years and NT-proBNP at diagnosis≥11,254 ng/L increased the specificity to 91%.Independent determinants of short time to diagnosis were age<8.8 years[aHR 0.34(0.13-0.88)],short distance to tertiary care hospital[aHR 0.27(0.08-0.92)],and the late period of the COVID-19 pandemic[aHR 2.48(1.05-5.85)].Conclusions Time to diagnosis≥6 days was independently associated with cardiogenic shock in MIS-C.Early diagnosis and treatment are crucial to avoid the use of inotropes and limit morbidity,especially in older children.