Enterotoxigenic Bacteroides fragilis infection exacerbates tumorigenesis in AOM/DSS mouse model

The Role of Diet and the Gut Microbiota in the Obesity-Colorectal Cancer Link

Obesity is positively associated with colorectal cancer (CRC) risk. Diet not only contributes to obesity, but also strongly influences the gut microbiota, a factor that is thought to independently affect CRC. To isolate the role of obesity-associated gut microbiota in CRC and to assess the impact of diet composition on this relationship, we transplanted the gut microbiota from donor mice that developed obesity or remained lean on a high-fat diet (HFD), Western diet (WD), or low-fat diet (LFD) into antibiotic-treated recipient mice that subsequently received azoxymethane to induce CRC. We hypothesized that the obesogenic diets of the donor mice, rather than their obesity status, would be a stronger driver of gut microbiota-mediated CRC development. Interestingly, while evidence supporting our hypothesis was observed, differential effects on CRC outcomes based on the type of obesogenic diets were found, such that HFD-associated gut microbiota promotes tumor incidence whereas WD-associated gut microbiota promotes tumor growth. Significantly enriched bacterial taxa present before tumor induction may be mediating these results through intestinal permeability or inflammation, such as Sutterella and Dorea in mice received HFD-associated gut microbiota, and Bacteroidetes in mice received WD-microbiota. Overall, our results demonstrated that diet drives the gut microbiota-derived impact on CRC development.

Therapeutic potential of fecal microbiota transplantation in colorectal cancer based on gut microbiota regulation: from pathogenesis to efficacy

Colorectal cancer (CRC) remains a leading cause of cancer-related deaths worldwide, with its progression intricately linked to gut microbiota dysbiosis. Disruptions in microbial homeostasis contribute to tumor initiation, immune suppression, and inflammation, establishing the microbiota as a key therapeutic target. Fecal microbiota transplantation (FMT) has emerged as a transformative approach to restore microbial balance, enhance immune responses, and reshape the tumor microenvironment. This review explores the mechanisms underlying FMT's therapeutic potential, evaluates its advantages over other microbiota-based interventions, and addresses challenges such as donor selection, safety concerns, and treatment standardization. Looking forward, the integration of FMT into personalized CRC therapies requires robust clinical trials and the identification of predictive biomarkers to optimize its efficacy and safety.

Metformin alleviates colitis-associated colorectal cancer via inhibition of the TLR4/MyD88/NFκB/MAPK pathway and macrophage M2 polarization

BACKGROUND

Colon inflammation plays an essential role in the development and progression of colorectal cancer. Emerging evidence from clinical and animal studies indicates that metformin may reduce the risk of colorectal cancer through its anti-inflammatory effects.

AIMS

To investigate the efficacy of metformin in reducing the risk of colorectal cancer and the possible pathways and mechanisms.

METHODS

The Enterotoxigenic Bacteroides Fragilis (ETBF)/azoxymethane (AOM)/dextran sulfate sodium (DSS) mouse model was established and low-dose metformin (125 mg/kg) or high-dose metformin (250 mg/kg) was administered daily by gavage. Colon tumors were counted, and colon tissue was stained with hematoxylin and eosin (HE) and Periodic Acid-Schiff's and Alcian Blue (PAS-AB). Colon Ki67, ZO-1 Muc2, Claudin-1, Occludin, MPO, reactive oxygen species (ROS), E-cadherin, CD206 and Arg-1 expression were detected by immunohistochemistry or immunofluorescence staining. NF-κB pathway-related protein expression was assessed by Western blot. Fecal short-chain fatty acid (SCFA) levels were also examined.

RESULTS

Our results showed that low- or high-dose metformin ameliorates colonic mucosal damage, reduces colonic inflammation, and eventually inhibits colorectal tumorigenesis in the ETBF/AOM/DSS mouse model. Our further research found that metformin suppresses the expression of TLR4/MyD88/NFκB/MAPK pathway-related proteins, modulates macrophage M2 polarization and increases SCFA levels in colon contents, which may be the mechanisms by which metformin exerts a protective effect against colon carcinogenesis.

CONCLUSION

Metformin inhibited colorectal tumorigenesis by suppressing the TLR4/MyD88/NFκB/MAPK pathway, modulating macrophage M2 polarization and increasing SCFA levels. It holds promise as a potentially effective treatment for colorectal cancer.

Caffeic Acid Phenethyl Ester Administration Reduces Enterotoxigenic Bacteroides fragilis-Induced Colitis and Tumorigenesis

The human colonic commensal enterotoxigenic Bacteroides fragilis (ETBF) is associated with chronic colitis and colon cancer. ETBF colonization induces colitis via the Bacteroides fragilis toxin (BFT). BFT secreted by ETBF cause colon inflammation via E-cadherin cleavage/NF-κB signaling. ETBF promotes colon tumorigenesis via interleukin 17A (IL-17A)/CXCL-dependent inflammation, but its bioactive therapeutics in ETBF-promoted tumorigenesis remain unexplored. In the current study, we investigated the caffeic acid phenethyl ester (CAPE) in the murine model of ETBF colitis and tumorigenesis. In this study, we observed that CAPE treatment mitigated inflammation induced by ETBF in mice. Additionally, our findings indicate that CAPE treatment offers protective effects against ETBF-enhanced colon tumorigenesis in a mouse model of colitis-associated colon cancer induced by azoxymethane (AOM) and dextran sulfate sodium. Notably, the decrease in colon tumorigenesis following CAPE administration correlates with a reduction in the expression of IL-17A and CXCL1 in the gastrointestinal tract. The molecular mechanism for CAPE-induced protection against ETBF-mediated tumorigenesis is mediated by IL-17A/CXCL1, and by NF-κB activity in intestinal epithelial cells. Our findings indicate that CAPE may serve as a preventive agent against the development of ETBF-induced colitis and colorectal cancer (CRC).

Nontoxigenic Bacteroides fragilis: A double-edged sword

The contribution of commensal microbes to human health and disease is unknown. Bacteroides fragilis (B. fragilis) is an opportunistic pathogen and a common colonizer of the human gut. Nontoxigenic B. fragilis (NTBF) and enterotoxigenic B. fragilis (ETBF) are two kinds of B. fragilis. NTBF has been shown to affect the host immune system and interact with gut microbes and pathogenic microbes. Previous studies indicated that certain strains of B. fragilis have the potential to serve as probiotics, based on their observed relationship with the immune system. However, several recent studies have shown detrimental effects on the host when beneficial gut bacteria are found in the digestive system or elsewhere. In some pathological conditions, NTBF may have adverse reactions. This paper presents a comprehensive analysis of NTBF ecology from the host-microbe perspective, encompassing molecular disease mechanisms analysis, bacteria-bacteria interaction, bacteria-host interaction, and the intricate ecological context of the gut. Our review provides much-needed insights into the precise application of NTBF.

Research progress on the correlation between intestinal flora and colorectal cancer

Colorectal cancer (CRC) is one of the most common gastrointestinal malignancies in the world. With the rapid pace of life and changes in diet structure, the incidence and mortality of CRC increase year by year posing a serious threat to human health. As the most complex and largest microecosystem in the human body, intestinal microecology is closely related to CRC. It is an important factor that affects and participates in the occurrence and development of CRC. Advances in next-generation sequencing technology and metagenomics have provided new insights into the ecology of gut microbes. It also helps to link intestinal flora with CRC, and the relationship between intestinal flora and CRC can be continuously understood from different levels. This paper summarizes the relationship between intestinal flora and CRC and its potential role in the diagnosis of CRC providing evidence for early screening and treatment of CRC.

Enrichment of Bacteroides fragilis and enterotoxigenic Bacteroides fragilis in CpG island methylator phenotype-high colorectal carcinoma

OBJECTIVES

Data support that enterotoxigenic Bacteroides fragilis (ETBF) harbouring the Bacteroides fragilis toxin (bft) gene may promote colorectal tumourigenesis through the serrated neoplasia pathway. We hypothesized that ETBF may be enriched in colorectal carcinoma subtypes with high-level CpG island methylator phenotype (CIMP-high), BRAF mutation, and high-level microsatellite instability (MSI-high).

METHODS

Quantitative PCR assays were designed to quantify DNA amounts of Bacteroides fragilis, ETBF, and each bft gene isotype (bft-1, bft-2, or bft-3) in colorectal carcinomas in the Health Professionals Follow-up Study and Nurses' Health Study. We used multivariable-adjusted logistic regression models with the inverse probability weighting method.

RESULTS

We documented 4476 colorectal cancer cases, including 1232 cases with available bacterial data. High DNA amounts of Bacteroides fragilis and ETBF were positively associated with BRAF mutation (p ≤ 0.0003), CIMP-high (p ≤ 0.0002), and MSI-high (p < 0.0001 and p = 0.01, respectively). Multivariable-adjusted odds ratios (with 95% confidence interval) for high Bacteroides fragilis were 1.40 (1.06-1.85) for CIMP-high and 2.14 (1.65-2.77) for MSI-high, but 1.02 (0.78-1.35) for BRAF mutation. Multivariable-adjusted odds ratios for high ETBF were 2.00 (1.16-3.45) for CIMP-high and 2.86 (1.64-5.00) for BRAF mutation, but 1.09 (0.67-1.76) for MSI-high. Neither Bacteroides fragilis nor ETBF was associated with colorectal cancer-specific or overall survival.

DISCUSSION

The tissue abundance of Bacteroides fragilis is associated with CIMP-high and MSI-high, whereas ETBF abundance is associated with CIMP-high and BRAF mutation in colorectal carcinoma. Our findings support the aetiological relevance of Bacteroides fragilis and ETBF in the serrated neoplasia pathway.

The microbial landscape of colorectal cancer

Colorectal cancer (CRC) is a substantial source of global morbidity and mortality in dire need of improved prevention and treatment strategies. As our understanding of CRC grows, it is becoming increasingly evident that the gut microbiota, consisting of trillions of microorganisms in direct interface with the colon, plays a substantial role in CRC development and progression. Understanding the roles that individual microorganisms and complex microbial communities play in CRC pathogenesis, along with their attendant mechanisms, will help yield novel preventive and therapeutic interventions for CRC. In this Review, we discuss recent evidence concerning global perturbations of the gut microbiota in CRC, associations of specific microorganisms with CRC, the underlying mechanisms by which microorganisms potentially drive CRC development and the roles of complex microbial communities in CRC pathogenesis. While our understanding of the relationship between the microbiota and CRC has improved in recent years, our findings highlight substantial gaps in current research that need to be filled before this knowledge can be used to the benefit of patients.

Sex differences in colorectal cancer: with a focus on sex hormone-gut microbiome axis

Sexual dimorphism has been observed in the incidence and prognosis of colorectal cancer (CRC), with men generally exhibiting a slightly higher incidence than women. Research suggests that this difference may be attributed to variations in sex steroid hormone levels and the gut microbiome. The gut microbiome in CRC shows variations in composition and function between the sexes, leading to the concept of 'microgenderome' and 'sex hormone-gut microbiome axis.' Conventional research indicates that estrogens, by promoting a more favorable gut microbiota, may reduce the risk of CRC. Conversely, androgens may have a direct pro-tumorigenic effect by increasing the proportion of opportunistic pathogens. The gut microbiota may also influence sex hormone levels by expressing specific enzymes or directly affecting gonadal function. However, this area remains controversial. This review aims to explore the differences in sex hormone in CRC incidence, the phenomenon of sexual dimorphism within the gut microbiome, and the intricate interplay of the sex hormone-gut microbiome axis in CRC. The objective is to gain a better understanding of these interactions and their potential clinical implications, as well as to introduce innovative approaches to CRC treatment.

The role of microbiomes in gastrointestinal cancers: new insights

Gastrointestinal (GI) cancers constitute more than 33% of new cancer cases worldwide and pose a considerable burden on public health. There exists a growing body of evidence that has systematically recorded an upward trajectory in GI malignancies within the last 5 to 10 years, thus presenting a formidable menace to the health of the human population. The perturbations in GI microbiota may have a noteworthy influence on the advancement of GI cancers; however, the precise mechanisms behind this association are still not comprehensively understood. Some bacteria have been observed to support cancer development, while others seem to provide a safeguard against it. Recent studies have indicated that alterations in the composition and abundance of microbiomes could be associated with the progression of various GI cancers, such as colorectal, gastric, hepatic, and esophageal cancers. Within this comprehensive analysis, we examine the significance of microbiomes, particularly those located in the intestines, in GI cancers. Furthermore, we explore the impact of microbiomes on various treatment modalities for GI cancer, including chemotherapy, immunotherapy, and radiotherapy. Additionally, we delve into the intricate mechanisms through which intestinal microbes influence the efficacy of GI cancer treatments.

Entero-toxigenic Bacteroides fragilis contributes to intestinal barrier injury and colorectal cancer progression by mediating the BFT/STAT3/ZEB2 pathway

Our previous findings confirmed the high enrichment of Bacteroides fragilis (BF) in fecal samples from patients with colorectal cancer (CRC). The intestinal mucosal barrier is the first defense of the organism against commensal flora and intestinal pathogens and is closely associated with the occurrence and development of CRC. Therefore, this study aimed to investigate the molecular mechanisms through which BF mediates intestinal barrier injury and CRC progression. SW480 cells and a Caco2 intestinal barrier model were treated with entero-toxigenic BF (ETBF), its enterotoxin (B. fragilis toxin, BFT), and non-toxigenic BF (NTBF). Cell counting kit-8, flow cytometry, wound healing and transwell assays were performed to analyze the proliferation, apoptosis, migration, and invasion of SW480 cells. Transmission electron microscopy, FITC-dextran, and transepithelial electrical resistance (TEER) were used to analyze damage in the Caco2 intestinal barrier model. The Azoxymethane/Dextran Sulfate Sodium (AOM/DSS) animal model was established to evaluate the effect of ETBF on intestinal barrier injury and CRC progression in vivo. ETBF and BFT enhanced the viability, wound healing ratio, invasion, and EMT of SW480 cells. In addition, ETBF and BFT disrupted the tight junctions and villus structure in the intestinal barrier model, resulting in increased permeability and reduced TEER. Similarly, the expression of intestinal barrier-related proteins (MUC2, Occludin and Zo-1) was restricted by ETBF and BFT. Interestingly, the STAT3/ZEB2 axis was activated by ETBF and BFT, and treatment with Brevilin A (a STAT3 inhibitor) or knockdown of ZEB2 limited the promotional effect of ETBF and BFT on the SW480 malignant phenotype. In vivo experiments also confirmed that ETBF colonization accelerated tumor load, carcinogenesis, and intestinal mucosal barrier damage in the colorectum of the AOM/DSS animal model, and that treatment with Brevilin A alleviated these processes. ETBF-secreted BFT accelerated intestinal barrier damage and CRC by activating the STAT3/ZEB2 axis. Our findings provide new insights and perspectives for the application of ETBF in CRC treatment.

Promotion of Colitis in B Cell-Deficient C57BL/6 Mice Infected with Enterotoxigenic Bacteroides fragilis

Enterotoxigenic Bacteroides fragilis (ETBF) causes colitis and is implicated in inflammatory bowel diseases and colorectal cancer. The ETBF-secreted B. fragilis toxin (BFT) causes cleavage of the adherence junction, the E-cadherin, resulting in the large intestine showing IL-17A inflammation in wild-type (WT) mice. However, intestinal pathology by ETBF infection is not fully understood in B-cell-deficient mice. In this study, ETBF-mediated inflammation was characterized in B-cell-deficient mice (muMT). WT or muMT C57BL/6J mice were orally inoculated with ETBF and examined for intestinal inflammation. The indirect indicators for colitis (loss of body weight and cecum weight, as well as mortality) were increased in muMT mice compared to WT mice. Histopathology and inflammatory genes (Nos2, Il-1β, Tnf-α, and Cxcl1) were elevated and persisted in the large intestine of muMT mice compared with WT mice during chronic ETBF infection. However, intestinal IL-17A expression was comparable between WT and muMT mice during infection. Consistently, flow cytometry analysis applied to the mesenteric lymph nodes showed a similar Th17 immune response in both WT and muMT mice. Despite elevated ETBF colonization, the ETBF-infected muMT mice showed no histopathology or inflammation in the small intestine. In conclusion, B cells play a protective role in ETBF-induced colitis, and IL-17A inflammation is not attributed to prompted colitis in B-cell-deficient mice. Our data support the fact that B cells are required to ameliorate ETBF infection-induced colitis in the host.

Gut microbiota and microbiota-derived metabolites in colorectal cancer: enemy or friend

Colorectal cancer (CRC) is a highly prevalent gastrointestinal cancer worldwide. Recent research has shown that the gut microbiota plays a significant role in the development of CRC. There is mounting evidence supporting the crucial contributions of bacteria-derived toxins and metabolites to cancer-related inflammation, immune imbalances, and the response to therapy. Besides, some gut microbiota and microbiota-derived metabolites have protective effects against CRC. This review aims to summarize the current studies on the effects and mechanisms of gut microbiota and microbiota-produced metabolites in the initiation, progression, and drug sensitivity/resistance of CRC. Additionally, we explore the clinical implications and future prospects of utilizing gut microbiota as innovative approaches for preventing and treating CRC.

Gut microbiota in colorectal cancer development and therapy

Colorectal cancer (CRC) is one of the commonest cancers globally. A unique aspect of CRC is its intimate association with the gut microbiota, which forms an essential part of the tumour microenvironment. Research over the past decade has established that dysbiosis of gut bacteria, fungi, viruses and Archaea accompanies colorectal tumorigenesis, and these changes might be causative. Data from mechanistic studies demonstrate the ability of the gut microbiota to interact with the colonic epithelia and immune cells of the host via the release of a diverse range of metabolites, proteins and macromolecules that regulate CRC development. Preclinical and some clinical evidence also underscores the role of the gut microbiota in modifying the therapeutic responses of patients with CRC to chemotherapy and immunotherapy. Herein, we summarize our current understanding of the role of gut microbiota in CRC and outline the potential translational and clinical implications for CRC diagnosis, prevention and treatment. Emphasis is placed on how the gut microbiota could now be better harnessed by developing targeted microbial therapeutics as chemopreventive agents against colorectal tumorigenesis, as adjuvants for chemotherapy and immunotherapy to boost drug efficacy and safety, and as non-invasive biomarkers for CRC screening and patient stratification. Finally, we highlight the hurdles and potential solutions to translating our knowledge of the gut microbiota into clinical practice.

Gut Microbiome Composition and Its Metabolites Are a Key Regulating Factor for Malignant Transformation, Metastasis and Antitumor Immunity

The genetic and metabolomic abundance of the microbiome exemplifies that the microbiome comprises a more extensive set of genes than the entire human genome, which justifies the numerous metabolic and immunological interactions between the gut microbiota, macroorganisms and immune processes. These interactions have local and systemic impacts that can influence the pathological process of carcinogenesis. The latter can be promoted, enhanced or inhibited by the interactions between the microbiota and the host. This review aimed to present evidence that interactions between the host and the gut microbiota might be a significant exogenic factor for cancer predisposition. It is beyond doubt that the cross-talk between microbiota and the host cells in terms of epigenetic modifications can regulate gene expression patterns and influence cell fate in both beneficial and adverse directions for the host's health. Furthermore, bacterial metabolites could shift pro- and anti-tumor processes in one direction or another. However, the exact mechanisms behind these interactions are elusive and require large-scale omics studies to better understand and possibly discover new therapeutic approaches for cancer.

Long-term Pu-erh tea consumption improves blue light-induced depression-like behaviors

Blue light emitted by smartphones and tablets at night increases the risk of depression. Pu-erh tea has been reported to reduce the risk of depression by regulating tryptophan metabolism, but its underlying protective mechanism on depression induced by blue light at night (BLAN) remains unclear. In this work, two groups of C57BL6/J mice were given water or 0.25% (w/v) Pu-erh tea for 120 days, followed by a 45-day BLAN treatment (400 lux blue light between 21:00 and 23:00) to simulate blue light emitted from electronic equipment. Our results indicated that BLAN induced depression-like behaviors and gut microbiota disorders in healthy mice. Pu-erh tea intake significantly reshaped the gut microbiome (especially Bifidobacterium) and regulated the metabolism of short-chain fatty acids (SCFAs) which protected the integrity of the intestinal barrier. This improvement further reduced blood-brain barrier (BBB) damage and alleviated neuroinflammation by inhibiting MyD88/NF-κB pathways which finally regulated neurotransmitters such as brain-derived neurotrophic factor (BDNF) and serotonin (5-hydroxytryptamine, 5-HT). Collectively, 0.25% (w/v) Pu-erh tea has the potential to prevent BLAN-induced depression-like behaviors by reshaping the gut microbiota and increasing the generation of SCFAs via the gut-brain axis.

Role of Bacteria in the Development of Colorectal Cancer

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the United States. Once limited to older populations, the incidence of CRC in patients under the age of 50 years is increasing and the etiology for this is uncertain. One hypothesis lies on the impact of the intestinal microbiome. The intestinal microbiome, composed primarily of bacteria but also viruses, fungi, and archaea, has been shown to regulate CRC development and progression both in vitro and in vivo. In this review, the role and intersection of the bacterial microbiome in various stages of clinical CRC development and management are discussed beginning with CRC screening. Various mechanisms whereby the microbiome has been shown to modulate CRC development including the influence of diet on the microbiome, bacterial-induced injury to the colonic epithelium, bacterial-produced toxins, and alteration of normal cancer immunosurveillance by the microbiome are discussed. Finally, the influence of microbiome on the response of CRC to treatment is discussed while highlighting ongoing clinical trials. The complexities of the microbiome and its role in CRC development and progression have become apparent and will require ongoing commitment to translate laboratory findings into meaningful clinical results that will aid more than 150,000 patients that develop CRC every year.

The gut microbiota of people with asthma influences lung inflammation in gnotobiotic mice

The gut microbiota in early childhood is linked to asthma risk, but may continue to affect older patients with asthma. Here, we profile the gut microbiota of 38 children (19 asthma, median age 8) and 57 adults (17 asthma, median age 28) by 16S rRNA sequencing and find individuals with asthma harbored compositional differences from healthy controls in both adults and children. We develop a model to aid the design of mechanistic experiments in gnotobiotic mice and show enterotoxigenic Bacteroides fragilis (ETBF) is more prevalent in the gut microbiota of patients with asthma compared to healthy controls. In mice, ETBF, modulated by community context, can increase oxidative stress in the lungs during allergic airway inflammation (AAI). Our results provide evidence that ETBF affects the phenotype of airway inflammation in a subset of patients with asthma which suggests that therapies targeting the gut microbiota may be helpful tools for asthma control.

Prevalence of pks + bacteria and enterotoxigenic Bacteroides fragilis in patients with colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third most diagnosed cancer and the second most common cause of cancer deaths worldwide. CRC patients present with an increase in pathogens in their gut microbiota, such as polyketide synthase-positive bacteria (pks +) and enterotoxigenic Bacteroides fragilis (ETBF). The pks + Escherichia coli promotes carcinogenesis and facilitates CRC progression through the production of colibactin, a genotoxin that induces double-strand DNA breaks (DSBs). ETBF is a procarcinogenic bacterium producing the B. fragilis toxin (bft) that promotes colorectal carcinogenesis by modulating the mucosal immune response and inducing epithelial cell changes.

METHODS

Fecal samples were collected from healthy controls (N = 62) and CRC patients (N = 94) from the province of Québec (Canada), and a bacterial DNA extraction was performed. Fecal DNA samples were then examined for the presence of the pks island gene and bft using conventional qualitative PCR.

RESULTS

We found that a high proportion of healthy controls are colonized by pks + bacteria (42%) and that these levels were similar in CRC patients (46%). bft was detected in 21% of healthy controls and 32% of CRC patients, while double colonization by both pks + bacteria and ETBF occurred in 8% of the healthy controls and 13% of the CRC patients. Most importantly, we found that early-onset CRC (< 50 years) patients were significantly less colonized with pks + bacteria (20%) compared to late-onset CRC patients (52%).

CONCLUSIONS

Healthy controls had similar levels of pks + bacteria and ETBF colonization as CRC patients, and their elevated levels may place both groups at greater risk of developing CRC. Colonization with pks + bacteria was less prevalent in early-compared to late-onset CRC.

Hainanolide inhibits the progression of colon cancer via inducing the cell cycle arrest, cell apoptosis and activation of the MAPK signaling pathway

Hainanolide (HN) is a norditerpenoid metabolite extract from Cephalotaxus fortunei Hook. f. C. fortunei Hook. f. is renowned for the active alkaloids, such as harringtonine (HT) and homoharringtonin (HTT), which have been clinically used to treat chronic myeloid leukemia. Nowadays, diterpenoids, another important metabolite, attracted the attention of chemists. Among them, Hainanolide (HN), a cephalotane-type diterpenoid, has been proven to possess potent antitumor activities. However, the underlying therapeutic mechanisms of HN in anti-tumor have not been investigated yet. Our present study demonstrated that HN inhibited HCT-116 and HCT-15 cell proliferation in a dose- and time-dependent manner. Further studies demonstrated that HN can induce G2/M phase arrest and alter the Cdc25C/Cdc2/CyclinB1 proteins. Western blot indicated that HN promoted apoptosis by up-regulating Bax and down-regulated Bcl-2. And the caspase-3 and caspase-9 activities of HCT-116 and HCT-15 cells were increased. Transcriptome analysis is used to reveal the possible mechanism. Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses suggested the genes were mainly enriched in the MAPK signaling pathway. Certainly, HN activates MAPK signaling pathway. In vivo, HN prevented the AOM/DSS-induced tumorigenesis of colon cancer in C57BL/6 mice. Our study indicated that HN inhibits the progression of colon cancer cells by blocking the cell cycle, inducing apoptosis, and activating the MAPK pathway. This study provides a theoretical and experimental scientific basis for future investigations of the antitumor effects of HN against colon cancer.

Self-assembled traditional Chinese nanomedicine modulating tumor immunosuppressive microenvironment for colorectal cancer immunotherapy

Colorectal cancer (CRC), mostly categorized as a low immunogenic microsatellite-stable phenotype bearing complex immunosuppressive tumor microenvironment (TME), is highly resistant to immunotherapy. Seeking safe and efficient alternatives aimed at modulating tumor immunosuppressive TME to improve outcome of CRC is highly anticipated yet remains challenging. Methods: Enlightened from the drug complementary art in traditional Chinese medicine, we designed a self-assembled nanomedicine (termed LNT-UA) by the natural active ingredients of ursolic acid (UA) and lentinan (LNT) through a simple nano-precipitation method, without any extra carriers, for CRC immunotherapy. Results: UA induces immunogenic cell death (ICD), while LNT further promotes dendritic cell (DC) maturation and repolarizes tumor-associated macrophage (TAM) from a protumorigenic M2 to an antitumor M1 phenotype. Co-delivery of UA and LNT by LNT-UA effectively reshapes the immunosuppressive TME and mobilizes innate and adaptive immunity to inhibit tumor progression in the CT26 CRC tumor model. Following the principle of integrative theoretical system of traditional Chinese medicine (TCM) on overall regulation, the further combination of LNT-UA and anti-CD47 antibody (αCD47) would reinforce the antitumor immunity by promoting phagocytosis of dying tumor cells and tumor-associated antigens (TAAs), leading to effective suppression of both primary and distant tumor growth with 2.2-fold longer of median survival time in the bilateral tumor model. Most notably, this combination effect is also observed in the spontaneous CRC model induced by chemical carcinogens, with much less and smaller size of tumor nodules after sequential administration of LNT-UA and αCD47 through gavage and intraperitoneal injection, respectively. Conclusions: This study provides a promising self-assembled traditional Chinese nanomedicine to improve immunotherapy for CRC, which might be applicable for future clinical translation.

A systemic review of the role of enterotoxic Bacteroides fragilis in colorectal cancer

Enterotoxigenic Bacteroides fragilis (ETBF) has received significant attention for a possible association with, or causal role in, colorectal cancer (CRC). The goal of this review was to assess the status of the published evidence supporting (i) the association between ETBF and CRC and (ii) the causal role of ETBF in CRC. PubMed and Scopus searches were performed in August 2021 to identify human, animal, and cell studies pertaining to the role of ETBF in CRC. Inclusion criteria included the use of cell lines, mice, exposure to BFT or ETBF, and detection of bft. Review studies were excluded, and studies were limited to the English language. Quality of study design and risk of bias analysis was performed on the cell, animal, and human studies using ToxRTools, SYRCLE, and NOS, respectively. Ninety-five eligible studies were identified, this included 22 human studies, 24 animal studies, 43 cell studies, and 6 studies that included both cells and mice studies. We found that a large majority of studies supported an association or causal role of ETBF in CRC, as well as high levels of study bias was detected in the in vitro and in vivo studies. The high-level heterogeneity in study design and reporting made it difficult to synthesize these findings into a unified conclusion, suggesting that the need for future studies that include improved mechanistic models, longitudinal in vitro and in vivo evidence, and appropriate control of confounding factors will be required to confirm whether ETBF has a direct role in CRC etiopathogenesis.

Identification of Senescence-Related Subtypes, the Development of a Prognosis Model, and Characterization of Immune Infiltration and Gut Microbiota in Colorectal Cancer

Cellular senescence is associated with tumorigenesis, and the subtype and prognostic signatures of senescence-related genes (SRGs) in the tumor microenvironment (TME) and gut microbiota have not been fully determined. Analysis of 91 SRGs obtained from the GSEA and MSigDB, and mRNA sequencing of genes in the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases enabled the identification of two distinct molecular types of colorectal cancer (CRC). Patient samples were clustered into two subtypes, with Kaplan-Meier survival analyses showing significant differences in patient survival between the two subtypes. Cluster C2 was associated with patient clinicopathological features, high immune score, high abundance of immune infiltrating cells and somewhat high abundance of bacteria. A risk model based on eight SRGs showed that a low risk score was characterized by inhibition of immune activity and was indicative of better prognosis in patients with CRC. In combination with clinical characteristics, risk score was found to be an independent prognostic predictor of survival in patients with CRC. In conclusion, the present study showed that senescence-related subtypes and a signature consisting of eight SRGs were associated with CRC patient prognosis, as well as with immune cell infiltration and gut microbiota. These findings may enable better prediction of CRC patient prognosis and facilitate individualized treatments.

Inflammatory bowel disease and carcinogenesis

Colorectal cancer (CRC) is the third most common cancer and the fourth most common cause of cancer mortality worldwide. Colitis-associated colorectal cancer (CAC) is a subtype of CRC associated with inflammatory bowel disease (IBD). It is well known that individuals with IBD have a 2-3 times higher risk of developing CRC than those who do not, rendering CAC a major cause of death in this group. Although the etiology and pathogenesis of CAC are incompletely understood, animal models of chronic inflammation and human cohort data indicate that changes in the intestinal environment, including host response dysregulation and gut microbiota perturbations, may contribute to the development of CAC. Genomic alterations are a hallmark of CAC, with patterns that are distinct from those in sporadic CRC. The discovery of the biological changes that underlie the development of CAC is ongoing; however, current data suggest that chronic inflammation in IBD increases the risk of developing CAC. Therefore, a deeper understanding of the precise mechanisms by which inflammation triggers genetic alterations and disrupts intestinal homeostasis may provide insight into novel therapeutic strategies for the prevention of CAC.

Chemically Induced Colitis-Associated Cancer Models in Rodents for Pharmacological Modulation: A Systematic Review

Animal models for colitis-associated colorectal cancer (CACC) represent an important tool to explore the mechanistic basis of cancer-related inflammation, providing important evidence that several inflammatory mediators play specific roles in the initiation and perpetuation of colitis and CACC. Although several original articles have been published describing the CACC model in rodents, there is no consensus about the induction method. This review aims to identify, summarize, compare, and discuss the chemical methods for the induction of CACC through the PRISMA methodology.

METHODS

We searched MEDLINE via the Pubmed platform for studies published through March 2021, using a highly sensitive search expression. The inclusion criteria were only original articles, articles where a chemically-induced animal model of CACC is described, preclinical studies in vivo with rodents, and articles published in English.

RESULTS

Chemically inducible models typically begin with the administration of a carcinogenic compound (as azoxymethane (AOM) or 1,2-dimethylhydrazine (DMH)), and inflammation is caused by repeated cycles of colitis-inducing agents (such as 2,4,6-trinitrobenzenesulfonic acid (TNBS) or dextran sulfate sodium (DSS)). The strains mostly used are C57BL/6 and Balb/c with 5-6 weeks. To characterize the preclinical model, the parameters more used include body weight, stool consistency and morbidity, inflammatory biomarkers such as tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-1β, angiogenesis markers such as proliferating cell nuclear antigen (PCNA), marker of proliferation Ki-67, and caspase 3, the presence of ulcers, thickness or hyperemia in the colon, and histological evaluation of inflammation.

CONCLUSION

The AOM administration seems to be important to the CACC induction method, since the carcinogenic effect is achieved with just one administration. DSS has been the more used inflammatory agent; however, the TNBS contribution should be more studied, since it allows a reliable, robust, and a highly reproducible animal model of intestinal inflammation.

Long-term maternal intake of inulin exacerbated the intestinal damage and inflammation of offspring rats in a DSS-induced colitis model

This study aimed to investigate the effects of long-term maternal intake of inulin on intestinal morphology, permeability, inflammation and microbiota of offspring rats treated with dextran sulfate sodium (DSS). Sixteen female adult Sprague-Dawley rats were assigned to two groups receiving the fiber-free diet (FFD) or inulin diet (INU, 5% inulin) for three parities. The offspring weaned rats (third-parity) were fed with the same diet for four weeks until receiving 6% DSS for 7 days; the four groups were as follows: FFD, FFD + DSS, INU and INU + DSS. The results showed that maternal intake of inulin increased the histopathology score and activity of diamine oxidase (DAO) in serum, and the highest histopathology scores and activity of DAO were observed in INU + DSS rats. Maternal intake of inulin increased the activity of myeloperoxidase (MPO), mRNA expressions of inflammatory factors and protein expression of IL-1β in colonic tissues. Likewise, INU + DSS rats had the highest activity of MPO and mRNA expressions of inflammatory factors in colonic tissues. Maternal intake of inulin increased the abundances of Bacteroidetes, Bacteroides and Parasutterella, which were the highest enriched in INU + DSS rats. The level of acetate in the colonic digesta of INU + DSS rats was lower than that in FFD and INU rats. These results indicated that long-term maternal intake of inulin exacerbated the intestinal damage and inflammation of DSS-induced offspring rats, associated with the decreased level of acetate and altered intestinal microbiota.

Bacteroides fragilis Toxin Induces Intestinal Epithelial Cell Secretion of Interleukin-8 by the E-Cadherin/β-Catenin/NF-κB Dependent Pathway

Enterotoxigenic Bacteroides fragilis (ETBF) has emerged as a gut microbiome pathogen that can promote colitis associated cancer in humans. ETBF secretes the metalloprotease, B. fragilis toxin (BFT), which can induce ectodomain cleavage of E-cadherin and IL-8 secretion through the β-catenin, NF-κB, and MAPK pathways in intestinal epithelial cells. However, it is still unclear whether E-cadherin cleavage is required for BFT induced IL-8 secretion and the relative contribution of these signaling pathways to IL-8 secretion. Using siRNA knockdown and CRISPR knockout studies, we found that E-cadherin cleavage is required for BFT mediated IL-8 secretion. In addition, genetic ablation of β-catenin indicates that β-catenin is required for the BFT induced increase in transcriptional activity of NF-κB, p65 nuclear localization and early IL-8 secretion. These results suggest that BFT induced β-catenin signaling is upstream of NF-κB activation. However, despite β-catenin gene disruption, BFT still activated the MAPK pathway, suggesting that the BFT induced activation of the MAPK signaling pathway is independent from the E-cadherin/β-catenin/NF-κB pathway. These findings show that E-cadherin and β-catenin play a critical role in acute inflammation following ETBF infection through the inflammatory response to BFT in intestinal epithelial cells.

Colorectal cancer: the facts in the case of the microbiota

The importance of the microbiota in the development of colorectal cancer (CRC) is increasingly evident, but identifying specific microbial features that influence CRC initiation and progression remains a central task for investigators. Studies determining the microbial mechanisms that directly contribute to CRC development or progression are revealing bacterial factors such as toxins that contribute to colorectal carcinogenesis. However, even when investigators have identified bacteria that express toxins, questions remain about the host determinants of a toxin's cancer-potentiating effects. For other cancer-correlating bacteria that lack toxins, the challenge is to define cancer-relevant virulence factors. Herein, we evaluate three CRC-correlating bacteria, colibactin-producing Escherichia coli, enterotoxigenic Bacteroides fragilis, and Fusobacterium nucleatum, for their virulence features relevant to CRC. We also consider the beneficial bioactivity of gut microbes by highlighting a microbial metabolite that may enhance CRC antitumor immunity. In doing so, we aim to elucidate unique and shared mechanisms underlying the microbiota's contributions to CRC and to accelerate investigation from target validation to CRC therapeutic discovery.

The roles of different Bacteroides fragilis strains in protecting against DSS-induced ulcerative colitis and related functional genes

The role of supplementation with different Bacteroides fragilis (B. fragilis) strains in alleviating ulcerative colitis (UC) is unclear due to the controversial results from animal experiments. In this study, three B. fragilis strains were evaluated for their ability to alleviate dextran sulfate sodium (DSS)-induced UC in C57BL/6J mice. We analyzed the anti-inflammatory effects of different B. fragilis strains and the changes they caused in the intestinal microbiota composition, intestinal epithelial permeability, cytokine concentrations, protein expression of nuclear factor kappa-B (NF-κB) and the underlying specific genes. The results showed that when orally administered, the different B. fragilis strains exerted different effects on the assessed parameters of the mice. The results of real-time quantitative polymerase chain reaction and immunofluorescence staining showed that the supplementation of B. fragilis FSHCM14E1, but not FJSWX11BF, enhanced the expression of the tight-junction proteins ZO-1, occludin and claudin-1. Western blot analysis showed that the anti-inflammatory effects of B. fragilis FSHCM14E1 were related to the NF-κB pathway. Genomic analysis suggested that the anti-inflammatory effects of FSHCM14E1 may be mediated through specific genes associated with defense mechanisms and the secretion of SCFAs. Overall, this study indicates the therapeutic potential of B. fragilis FSHCM14E1 for the prevention of UC.

From inflammation to colitis-associated colorectal cancer in inflammatory bowel disease: Pathogenesis and impact of current therapies

The risk of colorectal cancer (CRC) is higher in patients with inflammatory bowel disease (IBD). Population-based data from patients with ulcerative colitis (UC) estimate that the risk of CRC is approximately 2- to 3-fold that of the general population; patients with Crohn's disease appear to have a similar increased risk. However, the true extent of colitis-associated cancer (CAC) in undertreated IBD is unclear. Data suggest that the size (i.e., severity and extent) and persistence of the inflammatory process is largely responsible for the development of CRC in IBD. As patients with IBD and CRC have a worse prognosis than those without a history of IBD, the impact of current therapies for IBD on CAC is of importance. Chronic inflammation of the gut has been shown to increase the risk of developing CAC in both UC and CD. Therefore, control of inflammation is pivotal to the prevention of CAC. This review presents an overview of the current knowledge of CAC in IBD patients, focusing on the role of inflammation in the pathogenesis of CAC and the potential for IBD drugs to interfere with the process of carcinogenesis by reducing the inflammatory process or by modulating pathways directly involved in carcinogenesis.

Gut Microbiome of a Multiethnic Community Possessed No Predominant Microbiota

With increasing globalisation, various diets from around the world are readily available in global cities. This study aimed to verify if multiethnic dietary habits destabilised the gut microbiome in response to frequent changes, leading to readily colonisation of exogenous microbes. This may have health implications. We profiled Singapore young adults of different ethnicities for dietary habits, faecal type, gut microbiome and cytokine levels. Subjects were challenged with Lactobacillus casei, and corresponding changes in microbiome and cytokines were evaluated. Here, we found that the majority of young adults had normal stool types (73% Bristol Scale Types 3 and 4) and faecal microbiome categorised into three clusters, irrespective of race and gender. Cluster 1 was dominated by Bacteroides, Cluster 2 by Prevotella, while Cluster 3 showed a marginal increase in Blautia, Ruminococaceae and Ruminococcus, without a predominant microbiota. These youngsters in the three faecal microbiome clusters preferred Western high sugary beverages, Southeast Asian plant-rich diet and Asian/Western diets in rotation, respectively. Multiethnic dietary habits (Cluster 3) led to a gut microbiome without predominant microbiota yet demonstrated colonisation resistance to Lactobacillus. Although Bacteroides and Prevotella are reported to be health-promoting but also risk factors for some illnesses, Singapore-style dietary rotation habits may alleviate Bacteroides and Prevotella associated ill effects. Different immunological outcome was observed during consumption of the lactobacilli among the three microbiome clusters.

Microbiome or Infections: Amyloid-Containing Biofilms as a Trigger for Complex Human Diseases

The human microbiota is the community of microorganisms that live upon or within their human host. The microbiota consists of various microorganisms including bacteria, fungi, viruses, and archaea; the gut microbiota is comprised mostly of bacteria. Many bacterial species within the gut microbiome grow as biofilms, which are multicellular communities embedded in an extracellular matrix. Studies have shown that the relative abundances of bacterial species, and therefore biofilms and bacterial byproducts, change during progression of a variety of human diseases including gastrointestinal, autoimmune, neurodegenerative, and cancer. Studies have shown the location and proximity of the biofilms within the gastrointestinal tract might impact disease outcome. Gram-negative enteric bacteria secrete the amyloid curli, which makes up as much as 85% of the extracellular matrix of enteric biofilms. Curli mediates cell-cell attachment and attachment to various surfaces including extracellular matrix components such as fibronectin and laminin. Structurally, curli is strikingly similar to pathological and immunomodulatory human amyloids such as amyloid-β, which has been implicated in Alzheimer's disease, α-synuclein, which is involved in Parkinson's disease, and serum amyloid A, which is secreted during the acute phase of inflammation. The immune system recognizes both bacterial amyloid curli and human amyloids utilizing the same receptors, so curli also induces inflammation. Moreover, recent work indicates that curli can participate in the self-assembly process of pathological human amyloids. Curli is found within biofilms of commensal enteric bacteria as well as invasive pathogens; therefore, evidence suggests that curli contributes to complex human diseases. In this review, we summarize the recent findings on how bacterial biofilms containing curli participate in the pathological and immunological processes in gastrointestinal diseases, systemic autoimmune diseases, and neurodegenerative diseases.

Zerumbone Restores Gut Microbiota Composition in ETBF Colonized AOM/DSS Mice

Colorectal cancer (CRC) is the leading cause of common malignant neoplasm worldwide. Many studies have analyzed compositions of gut microbiota associated with various diseases such as inflammatory bowel diseases (IBD) and colon cancer. One of the most representative bacteria involved in CRC is enterotoxigenic Bacteroides fragilis (ETBF), a species belonging to phylum Bacteroidetes. We used ETBF colonized mice with azoxymethane (AOM)/dextran sulphate sodium (DSS) and zerumbone, a compound with anti-bacterial effect, to determine whether zerumbone could restore intestinal microbiota composition. Four experimental groups of mice were used: sham, ETBF colonized AOM/DSS group, ETBF colonized AOM/DSS group zerumbone 60 mg kg^-1 (ETBF/AOM/ DSS + Z (60)), and only zerumbone (60 mg kg^-1)-treated group. We performed reversible dye terminators-based analysis of 16S rRNA gene region V3-V4 for group comparison. Microbiota compositions of ETBF/AOM/DSS + Z (60) group and ETBF colonized AOM/DSS group not given zerumbone were significantly different. There were more Bacteroides in ETBF/AOM/DSS + Z (60) group than those in ETBF colonized AOM/DSS group, suggesting that B. fragilis could be a normal flora activated by zerumbone. In addition, based on linear discriminant analysis of effect size (LEfSe) analysis, microbial diversity decreased significantly in the ETBF colonized AOM/DSS group. However, after given zerumbone, the taxonomic relative abundance was increased. These findings suggest that zerumbone not only influenced the microbial diversity and richness, but also could be helpful for enhancing the balance of gut microbial composition. In this work, we demonstrate that zerumbone could restore the composition of intestinal microbiota.

Dietary Salt Administration Decreases Enterotoxigenic Bacteroides fragilis (ETBF)-Promoted Tumorigenesis via Inhibition of Colonic Inflammation

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.

Quorum Sensing System in Bacteroides thetaiotaomicron Strain Identified by Genome Sequence Analysis

This study is a bioinformatics assay on the microbial genome of Bacteroides thetaiotaomicron. The study focuses on the problem of quorum sensing as a result of adverse factors such as chemotherapy and antibiotic therapy. In patients with severe intestinal diseases, two strains of microorganisms were identified that were distinguished as new. Strains were investigated by conducting genome sequencing. The current concepts concerned with the quorum sensing system regulation by stationary-phase sigma factor and their coregulation of target genes in B. thetaiotaomicron were considered. The study suggested using bioinformatics data for the diagnosis of gastrointestinal disorders. In the course of the study, 402 genes having a greater than twofold change were identified with the 95% confidence level. The shortest and longest coding genes were predicted; the noncoding genes were detected. Biological pathways (KEGG pathways) were classified into the following categories: cellular processes, environmental information processing, genetic information processing, human disease, metabolism, and organismic systems. Among notable changes in the biofilm population observed in parallel to the planktonic B. thetaiotaomicron was the expression of genes in the polysaccharide utilization loci that were involved in the synthesis of O-glycans.

Roles of intestinal bacteroides in human health and diseases

Bacteroides, an abundant genus in the intestines of mammals, has been recently considered as the next generation probiotics (NGP) candidate due to its potential role in promoting host health. However, the role of Bacteroides in the development of intestinal dysfunctions such as diarrhea, inflammatory bowel disease, and colorectal cancer should not be overlooked. In the present study, we focused on nine most widely occurred and abundant Bacteroides species and discussed their roles in host immunity, glucose and lipid metabolism and the prevention or induction of diseases. Besides, we also discussed the current methods used in the safety evaluation of Bacteroides species and key opinions about the concerns of these strains for the future use.

Protective Effects of Zerumbone on Colonic Tumorigenesis in Enterotoxigenic Bacteroides fragilis (ETBF)-Colonized AOM/DSS BALB/c Mice

Chronic inflammation has been linked to colitis-associated colorectal cancer in humans. The human symbiont enterotoxigenic Bacteroides fragilis (ETBF), a pro-carcinogenic bacterium, has the potential to initiate and/or promote colorectal cancer. Antibiotic treatment of ETBF has shown promise in decreasing colonic polyp formation in murine models of colon cancer. However, there are no reported natural products that have shown efficacy in decreasing polyp burden. In this study, we investigated the chemopreventive effects of oral administration of zerumbone in ETBF-colonized mice with azoxymethane (AOM)/dextran sulfate sodium (DSS)-induced tumorigenesis. Zerumbone significantly reduced the severity of disease activity index (DAI) scores as well as several parameters of colonic inflammation (i.e., colon weight, colon length, cecum weight and spleen weight). In addition, inflammation of the colon and cecum as well as hyperplasia was reduced. Zerumbone treatment significantly inhibited colonic polyp numbers and prevented macroadenoma progression. Taken together, these findings suggest that oral treatment with zerumbone inhibited ETBF-promoted colon carcinogenesis in mice indicating that zerumbone could be employed as a promising protective agent against ETBF-mediated colorectal cancer.