The human intestine retains a complex microbial ecosystem, which performs crucial functions that impact on host health. Several studies have indicated that intestinal dysbiosis may impact on the establishment of life-threatening intestinal diseases such as colorectal cancer. An adenomatous polyp is the result of abnormal tissue growth, which is benign but is considered to be associated with a high risk of developing colorectal cancer, based on its grade of dysplasia. Development of diagnostic tools that are based on surveying the gut microbiota and are aimed at early detection of colorectal cancer represent highly desirable target. For this purpose, we performed a pilot study in which we applied a metataxonomic analysis based on 16S rRNA gene sequencing approach to unveil the composition of microbial communities of intestinal polyps. Moreover, we performed a meta-analysis involving the reconstructed microbiota composition of adenomatous polyps and publicly available metagenomics datasets of colorectal cancer. These analyses allowed the identification of microbial taxa such as Faecalibacterium, Bacteroides and Romboutsia, which appear to be depleted in cancerogenic mucosa as well as in adenomatous polyps, thus representing novel microbial biomarkers associated with early tumor formation. Furthermore, an absolute quantification of Fusubacterium nucleatum in polyps further compounded the important role of this microorganism as a valuable putative microbial biomarker for early diagnosis of colorectal cancer.

Background: The 'adenoma-carcinoma sequence' is a well-recognized model of colorectal cancer (CRC) development. However, the interaction between gut microbiota and genetic variation in the initiation of CRC is not clear. Our study attempts to demonstrate the relationship between gut microbiota and host genetics in patients with intestinal adenomatous polyps. Method: The entire exon region of the APC gene was sequenced in 35 patients with pathologically diagnosed adenomatous polyps. Patients with highly pathogenic APC mutation were classified as the case group, while the others were classified as the control group. The patients'stool and serum samples were respectively collected for metagenomics and metabolomics measurements. Results: In the analysis of gut microbiome, there were three most important species, in which Fusobacterium_mortiferum was significantly increased while Faecalibacterium_prausnitzii and Bifidobacterium_pseudocatenulatum were significantly decreased in the case group. The significantly low abundance of the Photosynthesis pathway in patients with APC mutation was due to the low abundance of species Faecalibacterium_prausnitzii and Bifidobacterium_pseudocatenulatum. Moreover, there were two clusters of KEGG pathways correlated with two clusters of species characterized by Faecalibacterium_prausnitzii and Fusobacterium_mortiferum. As to serum metabolomics, the abundance of (R)-3-Hydroxybutyric acid and 2-Hydroxyphenethylamine were significantly higher in patients with APC mutation, while the abundance of 1-Aminocyclopropanecarboxylic acid,7-Ketocholesterol, DL-lactate, and L-Pyroglutamic acid were significantly higher in controlgroup. After analyzing the metabolome and microbiome data by sparCCmethod, we found that there was a significantly negative correlation between the abundance of Faecalibacterium_prausnitzii and Fusobacterium_mortiferum, and a significantly positive correlation between Faecalibacterium_prausnitzii abundance and the steroid hormone Hydrocortisone (Cortisol) in serum. Conclusions: Host's APC mutation was closely related to the changes of gut microbiota and serum metabolites, and some species of gut microbiome like Faecalibacterium_prausnitzii and Fusobacterium_mortiferum might have the potential to predict the development of CRC from intestinal adenomatous polyps.

Colorectal cancer (CRC) is a leading cause of cancer deaths in the United States. Various risk factors have been associated with CRC including increasing age and diet. Epidemiological and experimental studies have implicated a diet high in fat as an important risk factor for colon cancer. High fat diets can promote obesity resulting in insulin resistance and inflammation and the development of oxidative stress, increased cell proliferation, and suppression of apoptosis. Because of the high consumption of dietary fats, especially saturated fats, by Western countries, it is of interest to see if non-nutrient food factors might be effective in preventing or delaying CRC in the presence of high saturated fat intake. Curcumin (Curcuma longa), the main yellow pigment in turmeric, was selected to test because of its reported anti-tumor activity. APC Min mice, which develop intestinal polyps and have many molecular features of CRC, were fed a diet containing 35% pork fat, 33% sucrose, and a protein and vitamin mineral mixture (HFD) with or without 0.5% curcumin. These cohorts were compared to APC Min mice receiving standard rodent chow (RC) with 8% fat. APC Min mice fed the HFD for 3 months had a 23% increase in total number of polyps compared to APC Min mice on RC. Curcumin was able to significantly reverse the accelerated polyp development associated with the HFD suggesting it may be effective clinically in helping prevent colon cancer even when ingesting high amounts of fatty foods. The anti-tumor effect of curcumin was shown to be associated with enhanced apoptosis and increased efficiency of DNA repair. Since curcumin prevented the gain in body weight seen in APC Min mice ingesting the HFD, modulation of energy metabolism may also be a factor.

Antitumor effect of berberine has been reported in a wide spectrum of cancer, however, the mechanisms of which are not fully understood. The aim of this study was to investigate the hypothesis that berberine suppresses tumorigenesis in the familial adenomatous polyposis (FAP) by regulating the macrophage polarization in Apc (min/+) mouse model. Berberine was given to Apc (min/+) mice for 12 weeks. Primary macrophages were isolated; after berberine treatment, the change in signaling cascade was determined. The total number and size of polyps were reduced remarkably in berberine group, compared with control group. A significant decrease in protein levels of F4/80, mannose receptor (MR), and COX-2 in stroma of intestinal polyps and an increase in the level of iNOS were observed after berberine treatment. The mRNA level of MR and Arg-1 in berberine group was significantly lower than those in IL-10 or IL-4 group, while no significant difference in mRNA levels of iNOS and CXCL10 was observed. The migration and invasiveness assays in vitro showed that berberine could reduce the capability of migration and invasiveness. These findings suggest that berberine attenuates intestinal tumorigenesis by inhibiting the migration and invasion of colorectal tumor cells via regulation of macrophage polarization.

Human colonic spirochetosis (CS) is usually due toBrachyspira pilosicolior Brachyspira aalborgiinfection. While traditionally considered to be commensal bacteria, there are scattered case reports and case series of gastrointestinal (GI) symptoms in CS and reports of colonic polyps with adherent spirochetes. We performed a systematic review and meta-analysis investigating the association between CS and GI symptoms and conditions including the irritable bowel syndrome (IBS) and colonic polyps. Following PRISMA 2020 guidelines, a systematic search of Medline, CINAHL, EMBASE, and Web of Science was performed using specific keywords for CS and GI disease. Pooled odds ratios (ORs) and 95% confidence intervals (CIs) were calculated using a random-effects model. Of 75 studies identified in the search, 8 case-control studies met the inclusion criteria for meta-analysis and 67 case series studies met the inclusion criteria for pooled prevalence analysis. CS was significantly associated with diarrhea (n = 141/127, cases/controls, OR: 4.19, 95% CI: 1.72-10.21, P = 0.002) and abdominal pain (n = 64/65, OR: 3.66, 95% CI: 1.43-9.35, P = 0.007). CS cases were significantly more likely to have Rome III-diagnosed IBS (n = 79/48, OR: 3.84, 95% CI: 1.44-10.20, P = 0.007), but not colonic polyps (n = 127/843, OR: 8.78, 95% CI: 0.75-103.36, P = 0.084). In conclusion, we found evidence of associations between CS and both diarrhea and IBS, but not colonic polyps. CS is likely underestimated due to suboptimal diagnostic methods and may be an overlooked risk factor for a subset of IBS patients with diarrhea.

Adenomatous polyps (APs) with inflammation are risk factors for colorectal cancer. However, the role of inflammation-related gut microbiota in promoting the progression of APs is unknown.

Colorectal cancer is a common cancer worldwide. Carbonic anhydrase (CA) catalyzes the reversible conversion of carbon dioxide to bicarbonate ion and a proton, and its inhibitor is reported to reduce cancer cell proliferation and induce apoptosis. Therefore, we asked whether acetazolamide, a CA inhibitor, could inhibit intestinal carcinogenesis. Five-week-old male Apc-mutant mice, Min mice, were fed a AIN-76A diet containing 200 or 400 ppm acetazolamide. As a result, acetazolamide treatment reduced the total number of intestinal polyps by up to 50% compared to the control group. In addition, the acetazolamide-treated group had low cell proliferation and a high apoptosis ratio in the intestinal polyp epithelial cells. Moreover, the mRNA expression level of proinflammatory cytokines, such as IL-6, involved in the cell proliferation was decreased in the polyp part of the acetazolamide-treated group. Next, we examined the effects of acetazolamide on the activation of several transcriptional factors (AP-1, HIF, HSF, NF-κB, NRF2, p53, and STAT3) using a reporter gene assay in human colon cancer cells, Caco-2 cells. Among the examined transcriptional factors, NRF2 transcriptional activation was strongly induced. NRF2-targeting genes, γGCS, GPx1, HO-1, and NQO-1, were also elevated in the intestinal polyps of acetazolamide-treated Min mice. Our results suggested that CA is involved in intestinal carcinogenesis. Acetazolamide could inhibit polyp formation through suppressing local/general cytokine levels, i.e., IL-6, via NRF2 activation.

CD1d-restricted invariant natural killer T (iNKT) cells are known as potent early regulatory cells of immune responses. Besides the established roles in the regulation of inflammation and autoimmune disease, studies have shown that iNKT cells have important roles in tumor surveillance and the control of tumor metastasis. Here we found that the absence of iNKT cells markedly decreased the total number of intestinal polyps in APCMin/+ mice, a model for colorectal cancer. Polyp iNKT cells were enriched for interleukin-10 (IL-10)- and IL-17-producing cells, showed a distinct phenotype being CD4+, NK1.1- CD44int, and PD-1lo, and they were negative for the NKT cell transcription factor promyelocytic leukemia zinc-finger. The absence of iNKT cells was associated with a reduced frequency of regulatory T (Tregs) cells and lower expression levels of FoxP3 protein and transcript uniquely in the polyps, and a switch to an inflammatory macrophage phenotype. Moreover, in iNKT cell-deficient APCMin/+ mice, expression of T-helper (TH) 1-associated genes, such as IFN-γ and Nos2, was increased in polyps, concomitantly with elevated frequencies of conventional CD4+ and CD8+ T cells in this tissue. The results suggest that a population of regulatory iNKT cells locally promote intestinal polyp formation by enhancing Treg cells and immunosuppression of antitumor TH1 immunity.

Some substances of plant origin have been reported to exert an effect in reducing intestinal neoplasm development, especially in animal models. Adenomatous polyposis coli multiple intestinal neoplasia - ApcMin/+ is the most studied murine model of genetic intestinal carcinogenesis.

As a traditional anti-inflammatory Chinese herbal medicine, Alkaloid berberine has been recently reported to exhibit anti-tumour effects against a wide spectrum of cancer. However, the mechanism was largely unknown. Gene chip array reveals that with berberine treatment, c-Myc, the target gene of Wnt pathway, was down-regulated 5.3-folds, indicating that berberine might inhibit Wnt signalling. TOPflash analysis revealed that Wnt activity was significantly reduced after berberine treatment, and the mechanism of which might be that berberine disrupted β-catenin transfer to nucleus through up-regulating the expression of adenomatous polyposis coli (APC) gene and stabilized APC-β-catenin complex. Berberine administration in ApcMin/+ mice exhibited fewer and smaller polyps in intestine, along with reduction in cyclin D1 and c-Myc expression. In clinical practice, oral administration of berberine also significantly reduced the familial adenomatous polyposis patients' polyp size along with the inhibition of cyclin D1 expression in polyp samples. These observations indicate that berberine inhibits colon tumour formation through inhibition of Wnt/β-catenin signalling and berberine might be a promising drug for the prevention of colon cancer.

Studies showed that manipulation of gut microbiota (GM) composition through the treatment of prebiotics could be a novel preventive measure against colorectal cancer (CRC) development. In this study, for the first time, we assessed the non-toxic doses of the triterpene saponins (ginsenoside-Rb3 and ginsenoside-Rd) - as prebiotics - that effectively reinstated the dysbiotic-gut microbial composition and intestinal microenvironment in an ApcMin/+ mice model. Rb3 and Rd effectively reduced the size and the number of the polyps that accompanied with the downregulation of oncogenic signaling molecules (iNOS, STAT3/pSTAT3, Src/pSrc). Both the compounds improved the gut epithelium by promoting goblet and Paneth cells population and reinstating the E-cadherin and N-Cadherin expression. Mucosal immunity remodeled with increased in anti-inflammatory cytokines and reduced in pro-inflammatory cytokines in treated mice. All these changes were correlating with the promoted growth of beneficial bacteria such as Bifidobacterium spp., Lactobacillus spp., Bacteroides acidifaciens, and Bacteroides xylanisolvens. Whereas, the abundance of cancer cachexia associated bacteria, such as Dysgonomonas spp. and Helicobacter spp., was profoundly lower in Rb3/Rd-treated mice. In conclusion, ginsenosides Rb3 and Rd exerted anti-cancer effects by holistically reinstating mucosal architecture, improving mucosal immunity, promoting beneficial bacteria, and down-regulating cancer-cachexia associated bacteria.

ERBB3 has gained attention as a potential therapeutic target to treat colorectal and other types of cancers. To confirm a previous study showing intestinal polyps are dependent upon ERBB3, we generated an intestinal epithelia-specific ERBB3 deletion in C57BL/6-ApcMin/+ mice. Contrary to the previous report showing a significant reduction in intestinal polyps with ablation of ERBB3 on a B6;129 mixed genetic background, we observed a significant increase in polyp number with ablation of ERBB3 on C57BL/6J compared to control littermates. We confirmed the genetic background dependency of ERBB3 by also analyzing polyp development on B6129 hybrid and B6;129 advanced intercross mixed genetic backgrounds, which showed that ERBB3 deficiency only reduced polyp number on the mixed background as previously reported. Increased polyp number with ablation of ERBB3 was also observed in C57BL/6J mice treated with azoxymethane showing the effect is model independent. Polyps forming in absence of ERBB3 were generally smaller than those forming in control mice, albeit the effect was greatest in genetic backgrounds with reduced polyp numbers. The mechanism for differential polyp number in the absence of ERBB3 was through altered proliferation. Backgrounds with increased polyp number with loss of ERBB3 showed an increase in cell proliferation even in non-tumor epithelia, while backgrounds showing reduced polyp number with loss of ERBB3 showed reduced cellular proliferation. Increase polyp number caused by loss of ERBB3 was mediated by increased epidermal growth factor receptor (EGFR) expression, which was confirmed by deletion of Egfr. Taken together, this study raises substantial implications on the use of ERBB3 inhibitors against colorectal cancer. The prediction is that some patients may have increased progression with ERBB3 inhibitor therapy, which is consistent with observations reported for ERBB3 inhibitor clinical trials.

Familial adenomatous polyposis is an inherited genetic disease, characterized by colorectal polyps. It is caused by inactivating mutations in the Adenomatous polyposis coli (Apc) gene. Mice carrying a nonsense mutation in the Apc gene at R850, which is designated ApcMin/+ (Multiple intestinal neoplasia), develop intestinal adenomas. Several genetic modifier loci of Min (Mom) were previously mapped, but so far, most of the underlying genes have not been identified. To identify novel modifier loci associated with ApcMin/+, we performed quantitative trait loci (QTL) analysis for polyp development using 49 F1 crosses between different Collaborative Cross (CC) lines and C57BL/6 J-ApcMin/+mice. The CC population is a genetic reference panel of recombinant inbred lines, each line independently descended from eight genetically diverse founder strains. C57BL/6 J-ApcMin/+ males were mated with females from 49 CC lines. F1 offspring were terminated at 23 weeks and polyp counts from three sub-regions (SB1-3) of small intestinal and colon were recorded.

The pathophysiological effects of non-cholinergic, non-adrenergic neuropeptides are well known in the nasal mucosa, but unclear in the polyps. Since the pathophysiological roles of neuropeptides depend on their presence in the target tissue, specimens of nasal polyps were removed from 20 patients and examined for the presence of vasoactive intestinal peptide (VIP), neuropeptide Y (NPY), dopamine-beta-hydroxylase (DBH), substance P (SP) and calcitonin gene-related peptide (CGRP). To visualize these neuropeptide fibers, immunohistochemical staining by the peroxidase-anti-peroxidase method and color reaction by Nickel enhancement of diaminobenzidine (DAB) were used. Fine varicose neuropeptides immunostained fibers were predominantly distributed in the pedicle of the polyps. No neuropeptides were found in the mucosal epithelium and subepithelium. NPY fibers were predominantly seen around the thick wall vessels, whereas the VIP fibers were mainly to be found in close proximity to the submucosal glands and fairly close to the vessels. SP or CGRP fibers were not found in the polyps. VIP and NPY in the pedicle of the polyps may be present in connection with mucosal inflammation, tissue edema and cystic degeneration of the glands in the early stage of polyp formation. Thus these neuropeptides may contribute to the development and growth of nasal polyps.

Colonic polyps are common tumors occurring in ~50% of Western populations with ~10% risk of malignant progression. Dietary agents have been considered the primary environmental exposure to promote colorectal cancer (CRC) development. However, the colonic mucosa is permanently in contact with the microbiota and its metabolic products including toxins that also have the potential to trigger oncogenic transformation.

Chymase, a chymotrypsin-like protease, is a non-angiotensin-converting enzyme (ACE) angiotensin II (Ang II)-generating enzyme. The aim of the present study was to investigate whether chymase activity was increased in inflammatory polyps of elderly patients with functional bowel disorder (FBD). This study enrolled 45 elderly patients with FBD and 44 healthy control individuals. Expression of chymase in intestinal mucosa was assessed using fluorescence quantitative polymerase chain reaction and immunohistochemistry (IHC). IHC showed an increased number of chymase-positive mast cells in inflammatory polyps than in healthy intestinal mucosa (P<0.05). Compared with healthy mucosa, expression of chymase at the mRNA and protein level was significantly higher in inflammatory polyps. The frequencies of the chymase GG genotype and the G allele type were higher in the intestinal mucosa of patients with FBD compared with healthy controls (66.67 versus 40.91%, 81.11 versus 63.63%, both P<0.05). The frequency of the G allele type in the intestinal mucosa of the C4 subgroup of FBD was higher than that in the control group. However, in other FBD subgroups, there was no difference between patients and controls. Based on the fact that enhanced chymase expression was observed in inflammatory polyps of elderly patients with FBD relative to those in healthy controls, it was concluded that chymase has a significant role in the pathogenesis of inflammatory polyps in elderly patients with FBD.

To examine the changes that occur in the immunohistochemistry of vasoconstrictor and vasodilator transmitters in nerves supplying early and advanced colorectal polyps.

Sessile serrated adenoma/polyp with dysplasia (SSA/P-D) is an SSA/P with cellular dysplasia and has a higher risk of progressing to colon carcinogenesis. Previously, we reported that tight junction impairment by Clostridium perfringens enterotoxin (CPE) leads to activation of the transcriptional co-activator yes-associated protein (YAP) in oral squamous cell carcinoma. Here, we investigated whether CPE activates YAP to promote the malignant progression of SSA/P. E-cadherin expression was lower in the 12 cases with SSA/P-D examined than that in normal mucosa, SSA/P, or tubular adenoma (TA). Furthermore, intracellular translocation of claudin-4 (CLDN4) and nuclear translocation of YAP were observed. The CPE gene was detected in DNA extracted from SSA/P-D lesions, but not in SSA/P or TA. Treatment of the rat intestinal epithelial cell line IEC6 with low-dose CPE resulted in intracellular translocation of CLDN4 to the cytoplasmic membrane. Cytoplasmic CLDN4 showed co-precipitation with transcriptional co-activator with PDZ-binding motif, zonula occludens (ZO)-1, large tumor suppressor, and mammalian Ste20-like. Additionally, YAP co-precipitated with ZO-2 under CPE treatment led to decreased YAP phosphorylation and nuclear translocation. YAP activation promoted increase in nuclear TEA domain family member level, expression of cyclin D1, snail, vimentin, CD44, NS and decrease in E-cadherin levels, thereby inducing stemness and epithelial-mesenchymal-transition (EMT). The Hippo complex with the incorporation of CLDN4 increased stability. Upon low-dose CPE treatment, HT29 cells with BRAFV600E gene mutation showed increased growth, enhanced invasive potential, stemness, and induced EMT phenotype, whereas HCT116 cells, which carry KRASG13D gene mutation, did not show such changes. In an examination of 10 colorectal cancers, an increase in EMT and stemness was observed in CPE (+) and BRAF mutation (+) cases. These findings suggest that C. perfringens might enhance the malignant transformation of SSA/P-D via YAP activation. Our findings further highlight the importance of controlling intestinal flora using probiotics or antibiotics.

We explored the hypothesis that an altered microenvironment (intestinal adenomatous polyp) could modify the differentiation program of bone marrow-derived stem cells (BMSCs), involving them in colon carcinogenesis. Sublethally irradiated 8-week-old female Apc(Min/+) mice were transplanted with bone marrow (BM) cells obtained from either male age-matched Apc(Min/+) (Apc-Tx-Apc) or wild type (WT) (WT-Tx-Apc) mice. At 4 and 7 weeks after transplantation, BM-derived colonocytes were recognized by colocalization of Y-chromosome and Cdx2 protein (specific colonocyte marker). Polyp number, volume, and grade of dysplasia were not influenced by irradiation/transplantation procedures since they were similar in both untreated female Apc(Min/+) and Apc-Tx-Apc mice. At 4 and 7 weeks after transplantation, a progressive significant reduction of polyp number and volume was observed in WT-Tx-Apc mice. Moreover, the number of WT-Tx-Apc mice with a high-grade dysplastic polyps significantly decreased as compared to Apc-Tx-Apc mice. Finally, at 4 and 7 weeks after transplantation, WT-Tx-Apc mice showed a progressive significant increase of Y+/Cdx2+ cells in "normal" mucosa, whereas, in the adenomatous tissue, Y+/Cdx2+ cells remained substantially unvaried. Our findings demonstrate that WT BMSCs do not participate in polyp development but rather inhibit their growth. The substitution of genotypically altered colonocytes with Y+/Cdx2+ cells probably contributes to this process.

Recently, underwater endoscopic mucosal resection (UEMR) without submucosal injection was introduced as a new replacement for conventional EMR (CEMR) and was reported to be useful for resecting large colonic polyps. Here, we aimed to assess the efficacy and safety of these two methods by a systematic review and meta-analysis. We comprehensively searched multiple databases until July 2021 to identify randomized controlled trials (RCTs) comparing UEMR with CEMR. The primary outcomes were the proportion of R0 resection and mean procedure time, and the secondary outcomes were the proportion of en bloc resection and all adverse events. Three reviewers independently searched for articles, extracted data, and assessed the risk of bias. We evaluated the certainty of evidence using the Grading of Recommendations, Assessment, Development, and Evaluation approach. This study was registered in www.protocols.io (Protocol Integer ID: 40849). We included six RCTs (1,374 polyps). We judged that a meta-analysis was not available, and the data were summarized narratively for the proportion of R0 resection. Regarding procedure time, UEMR likely resulted in a large reduction (mean difference = -64.3 seconds; 95% confidence interval (CI) = -122.5 to -6.0 seconds; I2 = 86%; moderate certainty of evidence). UEMR likely resulted in a large increase in en bloc resection (odds ratio = 1.85; 95% CI = 1.15 to 2.98; I2 = 60%; moderate certainty of evidence). Percentages of adverse events were 0-17% with CEMR and 0-16% with UEMR. In summary, UEMR might have higher efficacy than CEMR in the endoscopic resection of nonpedunculated colorectal polyps, with likely a large reduction in procedure time.