Similar Datasets
Project description:To elucidate whether Enterotoxigenic Bacteroides fragilis (ETBF) plays a role in intestinal inflammation and colorectal carcinogenesis, a RNA-seq analysis was performed to compare the microRNA profiles of exosomes derived from ETBF-treated HCT116 colorectal cancer cell lines.
2023-11-08 | GSE161048 | GEO
Project description:To elucidate whether Enterotoxigenic Bacteroides fragilis (ETBF) plays a role in intestinal inflammation and colorectal carcinogenesis, a RNA-seq analysis was performed to compare the microRNA profiles of ETBF treated HCT116 colorectal cancer cell lines.
2023-11-08 | GSE161047 | GEO
Project description:Long noncoding RNAs (lncRNAs) contribute to many steps in carcinogenesis and often serve as biomarkers or therapeutic targets for tumor diagnosis and therapy. Although the role of lncRNAs in tumor formation is becoming clear, whether lncRNAs mediate gut microbiota-induced colorectal cancer (CRC) is largely unknown. Enterotoxigenic Bacteroides fragilis (ETBF) is a well-known tumor-inducing bacterium in the human gut; however, its tumorigenic effect remains to be explored. In the present study, we revealed the mechanism by which a lncRNA participates in gut bacteria-induced carcinogenesis: Bacteroides fragilis-associated lncRNA1 (BFAL1) in CRC tissues mediates ETBF carcinogenesis. BFAL1 was highly expressed in CRC tissues compared with that in adjacent normal tissues. In vitro, BFAL1 was upregulated in ETBF-treated CRC cells. Mechanistically, ETBF promoted tumor growth via BFAL1 by activating the Ras homolog, which is the MTORC1 binding/mammalian target of the rapamycin (RHEB/mTOR) pathway. Furthermore, BFAL1 regulated RHEB expression by competitively sponging microRNAs miR-155-5p and miR-200a-3p. Clinically, both high expression of BFAL1 and high abundance of ETBF in CRC tissues predicted poor outcomes for patients with CRC. Thus, BFAL1 is a mediator of ETBF-induced carcinogenesis and may be a potential therapeutic target for ETBF-induced CRC.
| S-EPMC6742644 | biostudies-literature
Project description:To elucidate whether Enterotoxigenic Bacteroides fragilis (ETBF) plays a role in colorectal cancer tumorigenesis, a RNA-seq analysis was performed to compare the gene expression profiles of ETBF treated DLD-1 colorectal cancer cell lines.
2020-04-13 | GSE130152 | GEO
Project description:Many epithelial cancers are associated with chronic inflammation. However, the features of inflammation that are procarcinogenic are not fully understood. Regulatory T cells (Treg) typically restrain overt inflammatory responses and maintain intestinal immune homeostasis. Their immune-suppressive activity can inhibit inflammation-associated cancers. Paradoxically, we show that colonic Tregs initiate IL17-mediated carcinogenesis in multiple intestinal neoplasia mice colonized with the human symbiote enterotoxigenic Bacteroides fragilis (ETBF). Depletion of Tregs in ETBF-colonized C57BL/6 FOXP3(DTR) mice enhanced colitis but diminished tumorigenesis associated with shifting of mucosal cytokine profile from IL17 to IFN?; inhibition of ETBF-induced colon tumorigenesis was dependent on reduced IL17 inflammation and was independent of IFN?. Treg enhancement of IL17 production is cell-extrinsic. IL2 blockade restored Th17 responses and tumor formation in Treg-depleted animals. Our findings demonstrate that Tregs limit the availability of IL2 in the local microenvironment, allowing the Th17 development necessary to promote ETBF-triggered neoplasia, and thus unveil a new mechanism whereby Treg responses to intestinal bacterial infection can promote tumorigenesis.Tregs promote an oncogenic immune response to a common human symbiote associated with inflammatory bowel disease and colorectal cancer. Our data define mechanisms by which mucosal Tregs, despite suppressing excessive inflammation, promote the earliest stages of immune procarcinogenesis via enhancement of IL17 production at the expense of IFN? production.
| S-EPMC4592451 | biostudies-literature
Project description:BACKGROUND:Enterotoxigenic Bacteroides fragilis (ETBF) is a toxin-producing bacteria thought to possibly promote colorectal carcinogenesis by modulating the mucosal immune response and inducing epithelial cell changes. Here, we aim to examine the association of colonic mucosal colonization with ETBF and the presence of a range of lesions on the colonic neoplastic spectrum. METHODS:Mucosal tissue from up to four different colonic sites was obtained from a consecutive series of 150 patients referred for colonoscopy. The presence and relative abundance of the B. fragilis toxin gene (bft) in each tissue sample was determined using quantitative PCR, and associations with clinicopathological characteristics were analysed. FINDINGS:We found a high concordance of ETBF between different colonic sites (86%). Univariate analysis showed statistically significant associations between ETBF positivity and the presence of low-grade dysplasia (LGD), tubular adenomas (TA), and serrated polyps (P-values of 0.007, 0.027, and 0.007, respectively). A higher relative abundance of ETBF was significantly associated with LGD and TA (P-values of < 0.0001 and 0.025, respectively). Increased ETBF positivity and abundance was also associated with left-sided biopsies, compared to those from the right side of the colon. CONCLUSION:Our results showing association of ETBF positivity and increased abundance with early-stage carcinogenic lesions underlines its importance in the development of colorectal cancer, and we suggest that detection of ETBF may be a potential marker of early colorectal carcinogenesis.
| S-EPMC5289627 | biostudies-other
Project description:This SuperSeries is composed of the SubSeries listed below.
2018-04-18 | GSE113220 | GEO
Project description:Enterotoxigenic (ETBF) strains of Bacteroides fragilis are the subset of strains that secrete a toxin called fragilysin (Bft). Although ETBF strains are known to cause diarrheal disease and have recently been associated with colorectal cancer, they have not been well characterized. By sequencing the complete genome of four ETBF strains, we found that these strains exhibit considerable variation at the genomic level. Only a small number of genes that are located primarily in the Bft pathogenicity island (BFT PAI) and the flanking CTn86 conjugative transposon are conserved in all four strains and a fifth strain whose genome was previously sequenced. Interestingly, phylogenetic analysis strongly suggests that the BFT PAI was acquired by non-toxigenic (NTBF) strains multiple times during the course of evolution. At the phenotypic level, we found that the ETBF strains were less fit than the NTBF strain NCTC 9343 and were susceptible to a growth-inhibitory protein that it produces. The ETBF strains also showed a greater tendency to form biofilms, which may promote tumor formation, than NTBF strains. Although the genomic diversity of ETBF strains raises the possibility that they vary in their pathogenicity, our experimental results also suggest that they share common properties that are conferred by different combinations of non-universal genetic elements.
| S-EPMC4922554 | biostudies-literature
Project description:Enterotoxigenic Bacteroides fragilis (ETBF) is human intestinal commensal bacterium and a potent initiator of colitis through secretion of the metalloprotease Bacteroides fragilis toxin (BFT). BFT induces cleavage of E-cadherin in colon cells, which subsequently leads to NF-κB activation. Zerumbone is a key component of the Zingiber zerumbet (L.) Smith plant and can exhibit anti-bacterial and anti-inflammatory effects. However, whether zerumbone has anti-inflammatory effects in ETBF-induced colitis remains unknown. The aim of this study was to determine the anti-inflammatory effect of orally administered zerumbone in a murine model of ETBF infection. Wild-type C57BL/6 mice were infected with ETBF and orally administered zerumbone (30 or 60 mg/kg) once a day for 7 days. Treatment of ETBF-infected mice with zerumbone prevented weight loss and splenomegaly and reduced colonic inflammation with decreased macrophage infiltration. Zerumbone treatment significantly decreased expression of IL-17A, TNF-α, KC, and inducible nitric oxide synthase (iNOS) in colonic tissues of ETBF-infected mice. In addition, serum levels of KC and nitrite was also diminished. Zerumbone-treated ETBF-infected mice also showed decreased NF-κB signaling in the colon. HT29/C1 colonic epithelial cells treated with zerumbone suppressed BFT-induced NF-κB signaling and IL-8 secretion. However, BFT-mediated E-cadherin cleavage was unaffected. Furthermore, zerumbone did not affect ETBF colonization in mice. In conclusion, zerumbone decreased ETBF-induced colitis through inhibition of NF-κB signaling.
| S-EPMC6770904 | biostudies-other
Project description:Consumption of a Western-type diet has been linked to gut-microbiota-mediated colon inflammation that constitutes a risk factor for colorectal cancer. A high salt diet (HSD) exacerbates IL-17A-induced inflammation in inflammatory bowel disease and other autoimmune diseases. Enterotoxigenic Bacteroides fragilis (ETBF) is a gut commensal bacterium and reported to be a potent initiator of colitis via secretion of the Bacteroides fragilis toxin (BFT). BFT induces ectodomain cleavage of E-cadherin in colonic epithelial cells, consequently leading to cell rounding, epithelial barrier disruption, and the secretion of IL-8, which promotes tumorigenesis in mice via IL-17A-mediated inflammation. A HSD is characteristic of the Western-type diet and can exhibit inflammatory effects. However, a HSD induces effects in ETBF-induced colitis and tumorigenesis remain unknown. In this study, we investigated HSD effects in ETBF-colonized mice with azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced tumorigenesis as well as ETBF colitis mice. Unexpectedly, ETBF-infected mice fed a HSD exhibited decreased weight loss and splenomegaly and reduction of colon inflammation. The HSD significantly decreased the expression of IL-17A and inducible nitric oxide synthase (iNOS) in the colonic tissues of ETBF-infected mice. In addition, serum levels of IL-17A and nitric oxide (NO) were also diminished. However, HT29/C1 colonic epithelial cells treated with sodium chloride showed no changes in BFT-induced cellular rounding and IL-8 expression. Furthermore, HSD did not affect ETBF colonization in mice. In conclusion, HSD decreased ETBF-induced tumorigenesis through suppression of IL-17A and iNOS expression in the colon. HSD also inhibited colonic polyp numbers in the ETBF-infected AOM/DSS mice. Taken together, these findings suggest that a HSD consumption inhibited ETBF-promoted colon carcinogenesis in mice, indicating that a HSD could have beneficial effects under certain conditions.
| S-EPMC7663446 | biostudies-literature