The gut microbiome modulates colon tumorigenesis. mBio. 2013;4:e00692-e00613. [PMID: 24194538 PMCID: PMC3892781 DOI: 10.1128/mbio.00692-13]

Inactivation of glutathione S-transferase alpha 4 blocks Enterococcus faecalis-induced bystander effect by promoting macrophage ferroptosis

Enterococcus faecalis-infected macrophages produce 4-hydroxynonenal (4-HNE) that mediates microbiota-induced bystander effect (MIBE) leading to colorectal cancer (CRC). Glutathione S-transferase alpha 4 (Gsta4), a specific detoxifying enzyme for 4-HNE, is overexpressed in human CRC and E. faecalis-induced murine CRC. However, the roles of Gsta4 in E. faecalis-induced colitis and CRC remain unclear. Herein, we demonstrate that Gsta4 is essential for MIBE by protecting macrophages from E. faecalis-induced ferroptosis. E. faecalis OG1RFSS was used to induce colitis in Gsta4-/- and Il10-/-/Gsta4-/- mice by orogastric gavage. Ferroptosis was assessed in Gsta4-deficient murine macrophages. We found that, unlike Il10-/- mice, Gsta4-/- and Il10-/-/Gsta4-/- mice colonized with E. faecalis failed to develop colitis or CRC. Immunofluorescent staining showed a reduction of macrophages in the lamina propria of E. faecalis-colonized Il10-/-/Gsta4-/- mice, as well as decreased Gpx4 expression, indicating the occurrence of ferroptosis. Ferroptosis was further confirmed in Gsta4-deficient murine macrophages infected with E. faecalis. Moreover, Gsta4 inactivation induced the upregulation of Hmox1 and phosphorylated c-Jun while blocked Nos2 expression, leading to the accumulation of intracellular ferrous iron, lipid peroxidation and, eventually, ferroptosis. Finally, Mapk8, as a ferroptosis driver, was remarkably elevated in E. faecalis-infected Gsta4-deficient macrophages. These results suggest that Gsta4 inactivation blocks MIBE by eliminating macrophages, thereby attenuates E. faecalis-induced colitis and CRC.

Baseline abundance of Akkermansia muciniphila and Bacteroides acidifaciens in a healthy state predicts inflammation associated tumorigenesis in the AOM/DSS mouse model

Numerous studies demonstrate that intestinal microbiota contribute to colorectal cancer (CRC), which is often associated with dysbiosis. Most of the data were obtained from studies on CRC patients, making it challenging to determine whether alterations in microbiota are a consequence of the pathology or whether they actively drive its progression. Several studies using laboratory animals suggest that gut microbiota may be involved in both the onset and progression of CRC. In the present study we utilized the azoxymethane-dextran sulfate sodium (AOM/DSS) mouse model of CRC to investigate the contribution of healthy-state microbiota to inflammation-associated tumorigenesis. Two cohorts of C57BL/6 mice harboring different intestinal microbiota demonstrated different susceptibility to AOM/DSS treatment. Sequencing of 16S rRNA bacterial DNA from fecal samples revealed Akkermansia muciniphila and Bacteroides acidifaciens as marker features in the healthy-state microbiota (before AOM/DSS administration), which showed a strong positive correlation with tumor incidence. Moreover, the healthy-state abundance of these markers, considered beneficial bacteria, was strongly positively correlated with the sulfate-reducing bacteria Desulfovibrio fairfieldensis identified as a marker of chronic colitis-associated microbiota. Furthermore, the abundances of these marker features, associated with CRC outcome, correlated with the expression of interferon gamma and nitric oxide synthase 2 genes in colon tissue during the early stage of DSS-induced intestinal inflammation. In contrast to multiple studies demonstrating the anti-inflammatory properties of A. muciniphila and B. acidifaciens, our results point out their potential adverse effect under specific conditions of genotoxicity and inflammation in the intestine. Taken together, our findings suggest a complex, context-dependent role of commensal microbiota in inflammation-associated dysbiosis and CRC.

Biofilm development as a factor driving the degradation of plasticised marine microplastics

Biodegradation of microplastics facilitated by natural marine biofouling is a promising approach for ocean bioremediation. However, implementation requires a comprehensive understanding of how interactions between the marine microbiome and dominant microplastic debris types (e.g., polymer and additive combinations) can influence biofilm development and drive biodegradation. To investigate this, polystyrene (PS) and polyvinyl chloride (PVC) microplastics (< 200 µm in diameter) were prepared either without any additives (i.e., virgin) or containing 15 wt% of the plasticisers diethylhexyl phthalate (DEHP) or bisphenol A (BPA). Each polymer-plasticiser microplastic combination was exposed to environmentally relevant conditions in a simulated seawater mesocosm representative of tropical reef waters over a 21-day period to allow for natural biofilm development. Following this, microplastic degradation and the colonising bacterial biofilm was assessed as a function of time, polymer and plasticiser type using infrared, thermal, gel permeation and surface characterisation techniques, as well as 16S ribosomal RNA bacterial gene sequencing, respectively. Together, these analyses revealed time-, polymer- and plasticiser-dependent degradation, particularly of the PS-BPA microplastics. Degradation of the PS-BPA microplastics also coincided with changes in bacterial community composition and an increased total relative abundance of putative biodegradative bacteria. These findings indicate that the metabolic potential and biodegradative capability of the colonising marine biofilm can be significantly impacted by the chemical properties of the microplastic substrate, even within short timeframes.

Gut microbiome differences and disease risk in colorectal cancer relatives and healthy individuals

Given the heightened focus on high-risk populations, this study aimed to provide insights into early susceptibility and preventive strategies for colorectal cancer (CRC) by focusing on high-risk populations. In this research, fecal samples from 1,647 individuals across three discovery cohorts and nine external validation cohorts were sequenced using whole-genome metagenomic sequencing. A prediction model based on random forest was constructed using the nine external cohorts and independently validated with the three discovery cohorts. A disease probability (POD) model based on microbial biomarkers was developed to assess CRC risk. We found that the gut microbiome composition of CRC relatives differed from that of controls, with enrichment of species such as Fusobacterium and Bacteroides and a reduction in beneficial genera like Coprococcus and Roseburia. Additionally, dietary red meat intake emerged as a risk factor. The POD model indicated an elevated risk of CRC in unaffected relatives. The findings suggest that the POD for CRC may be increased in unaffected relatives or individuals living in shared environments, although this difference did not reach statistical significance. Our study introduces a novel framework for assessing the risk of colorectal cancer in ostensibly healthy individuals.

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.

Pterostilbene Exhibited the Anticancer Effect Against 1, 2-Dimethylhydrazine (DMH)-Induced Colorectal Cancer via Alteration of Oxidative Stress, Inflammation and Gut Microbiota

Colorectal cancer (CRC) is the third leading cause of cancer-related deaths worldwide. The current investigation aimed to assess the chemoprotective effects of pterostilbene against 1,2-dimethylhydrazine (DMH)-induced colorectal cancer in mice. An in-silico study was conducted to perform docking studies against nuclear factor kappa factor (NF-κB). CRC was induced in mice by administering DMH (20 mg/kg) subcutaneously, and the mice were subsequently administered various dosages of pterostilbene (5, 10, and 15 mg/kg). At the end of the study, various biochemical parameters, including inflammatory cytokines, inflammatory markers, and antioxidant enzymes, were examined. Additionally, the mice's stools were collected for the analysis of intestinal microbiota. A total of 5 hydrogen bonds were identified between NF-κB and pterostilbene using LigPlot+. Pterostilbene significantly (p < 0.001) reduced tumor incidence, tumor weight, and increased body weight. Pterostilbene significantly (p < 0.001) altered the levels of lipid peroxidation, reduced glutathione, superoxide dismutase, glutathione peroxidase, and catalase as well as the activity of both phase I and phase II enzymes. Furthermore, pterostilbene significantly (p < 0.001) decreased the levels of proinflammatory cytokines such as tumor necrosis factor-α, interleukin-6, interferon-γ, and interleukin-1β, while increasing the levels of anti-inflammatory cytokines like interleukin-4 and interleukin-10. Pterostilbene considerably suppressed the levels of cyclooxygenase-2 and prostaglandin E2, as well as inducible nitric oxide synthase and simultaneously elevated the levels of apoptosis-related parameters, including caspase-3, caspase-8, and caspase-9. Moreover, pterostilbene significantly reduced the abundance of Staphylococcus in the intestinal microbiota and enhanced the levels of beneficial bacteria, such as Bifidobacterium, Akkermansia, and Lactobacillus. Pterostilbene demonstrated a chemoprotective effect against CRC by effectively reducing oxidative stress, mitigating inflammatory responses, and inducing alterations in gut microbiota levels.

The Role of the Gut Microbiota in Modulating Signaling Pathways and Oxidative Stress in Glioma Therapies

Tumors of the central nervous system (CNS), especially gliomas, pose a significant clinical challenge due to their aggressive nature and limited therapeutic options. Emerging research highlights the critical role of the gut microbiota in regulating CNS health and disease. The composition of the gut microbiota is essential for maintaining CNS homeostasis, as it modulates immune responses, oxidative status, and neuroinflammation. The microbiota-gut-brain axis, a bidirectional communication network, plays a pivotal role in cancer and CNS disease treatment, exerting its influence through neural, endocrine, immunological, and metabolic pathways. Recent studies suggest that the gut microbiota influences the solidification of the tumor microenvironment and that dysbiosis may promote glioma development by modulating systemic inflammation and oxidative stress, which contributes to tumorigenesis and CNS tumor progression. This review interrogates the impact of the gut microbiota on glioma, focusing on critical pathways such as NF-κB, MAPK, PI3K/Akt/mTOR, and Kynurenine/AhR that drive tumor proliferation, immune evasion, and therapy resistance. Furthermore, we explore emerging therapeutic strategies, including probiotics and microbiota-based interventions, which show potential in modulating these pathways and enhancing immunotherapies such as checkpoint inhibitors. By focusing on the multifaceted interactions between the gut microbiota, oxidative stress, and CNS tumors, this review highlights the potential of microbiota-targeted therapies and their manipulation to complement and enhance current treatments.

Protective Effect of Ganjang, a Traditional Fermented Soy Sauce, on Colitis-Associated Colorectal Cancer in Mice

Colorectal cancer (CRC) is one of the most prevalent causes of cancer-related fatalities globally, and its development is closely associated with dietary and microbial factors. The aim of this study was to investigate the potential of ganjang, a traditional fermented soy sauce, in alleviating colitis-associated colorectal cancer (CAC) in a mouse model induced by azoxymethane/dextran sulfate sodium (AOM/DSS). The bacterial composition of ganjang samples from different regions primarily included Lactobacillus spp. and Bacillus spp. Administration of ganjang to AOM/DSS-induced mice significantly improved CAC-related symptoms, including increased body weight, restored colon length, and reduced spleen size. Additionally, ganjang administration led to a decrease in tumor size and number, the modulation of apoptotic and proliferative markers, decreased inflammatory cytokine levels, and the restoration of the intestinal epithelial barrier. Furthermore, ganjang samples altered the gut microbiota composition by increasing the relative abundance of Lactobacillus spp. These findings suggest that ganjang has potential as a functional food for CRC prevention or mitigation, primarily through the modulation of CAC symptoms, tumor growth, inflammatory responses, intestinal epithelial barrier integrity, and gut microbiota composition.

Intestinal microbiota as biomarkers for different colorectal lesions based on colorectal cancer screening participants in community

Introduction

The dysregulation of intestinal microbiota has been implicated in the pathogenesis of colorectal cancer (CRC). However, the utilization of intestinal microbiota for identify the lesions in different procedures in CRC screening populations remains limited.

Methods

A total of 529 high-risk individuals who underwent CRC screening were included, comprising 13 advanced adenomas (Aade), 5 CRC, 59 non-advanced adenomas (Nade), 129 colon polyps (Pol), 99 cases of colorectal inflammatory disease (Inf), and 224 normal controls (Nor). 16S rRNA gene sequencing was used to profile the intestinal microbiota communities. The Gut Microbiota Health Index (GMHI) and average variation degree (AVD) were employed to assess the health status of the different groups.

Results

Our findings revealed that the Nor group exhibited significantly higher GMHIs and the lowest AVD compared to the four Lesion groups. The model incorporating 13 bacterial genera demonstrated optimal efficacy in distinguishing CRC and Aade from Nor, with an area under the curve (AUC) of 0.81 and a 95% confidence interval (CI) of 0.72 to 0.89. Specifically, the 55 bacterial genera combination model exhibited superior performance in differentiating CRC from Nor (AUC 0.98; 95% CI, 0.96-1), the 25 bacterial genera combination showed superior performance in distinguishing Aade from Nor (AUC 0.95). Additionally, the 27 bacterial genera combination demonstrated superior efficacy in differentiating Nade from Nor (AUC 0.82). The 13 bacterial genera combination exhibited optimal performance in distinguishing Inf from Nor (AUC 0.71).

Discussion

Our study has identified specific microbial biomarkers that can differentiate between colorectal lesions and healthy individuals. The intestinal microbiota markers identified may serve as valuable tools in community-based CRC screening programs.

Gut colonization of Bacteroides plebeius suppresses colitis-associated colon cancer development

Colon cancer development may be initiated by multiple factors, including chronic inflammation, genetic disposition, and gut dysbiosis. The loss of beneficial bacteria and increased abundance of detrimental microbes exacerbates disease progression. Bacteroides plebeius (B. plebeius) is a human gut microbe, and its colon colonization is enhanced by a seaweed-supplemented diet. We found that mice orally administered with B. plebeius and fed a diet containing 1% seaweed developed a unique gut microbial composition. By linear discriminant analysis effect size analysis, we found that B. plebeius colonization increased the abundance of Blautia coccoides and reduced the abundance of Akkermansia sp. and Dubosiella sp. We also showed that colonization of B. plebeius suppressed the colon tumor development induced by azoxymethane/dextran sulfate sodium in specific-pathogen-free mice, coinciding with a reduced abundance of Muribaculaceae sp., Closteridale sp., and Bilophila sp. Moreover, B. plebeius colonization in gnotobiotic mice resulted in enhanced production of selected metabolites, including propionic, taurocholic, cholic, alpha-, and beta-muricholic, as well as ursodeoxycholic acids. Importantly, some of these metabolites show anti-inflammatory and tumor-suppressive effects. We conclude that B. plebeius is able to restructure the gut microbial community and produce beneficial metabolites, leading to inhibition of colitis-associated colon cancer development.IMPORTANCEThis work delves into the pivotal role of gut microbiota in suppressing the progression of colitis-associated colon cancer. By investigating the impact of Bacteroides plebeius that can be colonized in mouse gut by feeding the animal with seaweed diet, we unveil a novel mechanism through which this beneficial bacterium reshapes the gut microbial community and produces metabolites with anti-inflammatory and tumor-suppressive properties. Such findings underscore the potential of harnessing specific microbes, like B. plebeius shown in this study, to modulate the gut ecosystem and mitigate the risk of colitis-associated colon cancer.

Alternative Splicing at the Crossroad of Inflammatory Bowel Diseases and Colitis-Associated Colon Cancer

The risk of developing colorectal cancer (CRC) is increased in ulcerative colitis patients compared to the general population. This increased risk results from the state of chronic inflammation, a well-known tumour-promoting condition. This review explores the pathologic and molecular characteristics of colitis-associated colon cancer (CAC), emphasizing the distinct features from sporadic CRC. We focus on the key signalling pathways involved in the transition to CAC, highlighting the emerging role of alternative splicing in these processes, namely on how inflammation-induced alternative splicing can significantly contribute to the increased CRC risk observed among UC patients. This review calls for more transcriptomic studies to elucidate the molecular mechanisms through which inflammation-induced alternative splicing drives CAC pathogenesis. A better understanding of these splicing events is crucial as they may reveal novel biomarkers for disease progression and have the potential to target changes in alternative splicing as a therapeutic strategy.

Oral administration of Bifidobacterium longum and Bifidobacterium infantis ameliorates cefcapene pivoxil-induced attenuation of anti-programmed cell death protein-1 antibody action in mice

Gut bacteria play pivotal roles in the antitumor effects of immune checkpoint inhibitors (ICIs). However, antimicrobial therapy, often necessary for infections in cancer patients, can reduce the efficacy of ICIs. The potential of probiotics to restore ICI efficacy remains uncertain. This study evaluated the effects of Bifidobacterium longum and Bifidobacterium infantis (BLBI) in a CT-26 subcutaneous tumor mouse model treated with anti-programmed cell death protein 1 antibody (αPD-1) and cefcapene pivoxil (CFPN-PI). BALB/c mice received daily oral gavage of CFPN-PI for 5 days before tumor inoculation, followed by weekly αPD-1 administration and tumor growth monitoring. BLBI was administered via ad libitum feeding, mixed in powdered feed. Gut microbiota composition and fecal short-chain fatty acid concentrations were assessed, along with gene expression and immune cell populations in the tumor microenvironment, using quantitative RT-PCR and flow cytometry, respectively. CFPN-PI alone increased tumor growth and attenuated the antitumor effect of αPD-1. In contrast, BLBI inhibited CFPN-PI-induced tumor growth and improved the efficacy of αPD-1. Probiotic treatment increased the stool propionic acid concentration and the number of tumor-infiltrating conventional type 1 dendritic cells. Relative decreases in Bacteroides and Lachnospiraceae _NK4A136_group species and relative increases in Muribaculaceae and Unclassified_f_Oscillospiraceae species correlated with an improved αPD-1 response. These results suggest that probiotic administration may be a new therapeutic strategy to rescue the attenuated efficacy of ICIs in patients with cancer who require antimicrobial therapy.

Gut microbiota in cancer initiation, development and therapy

Cancer has long been associated with genetic and environmental factors, but recent studies reveal the important role of gut microbiota in its initiation and progression. Around 13% of cancers are linked to infectious agents, highlighting the need to identify the specific microorganisms involved. Gut microbiota can either promote or inhibit cancer growth by influencing oncogenic signaling pathways and altering immune responses. Dysbiosis can lead to cancer, while certain probiotics and their metabolites may help reestablish micro-ecological balance and improve anti-tumor immune responses. Research into targeted approaches that enhance therapy with probiotics is promising. However, the effects of probiotics in humans are complex and not yet fully understood. Additionally, methods to counteract harmful bacteria are still in development. Early clinical trials also indicate that modifying gut microbiota may help manage side effects of cancer treatments. Ongoing research is crucial to understand better how gut microbiota can be used to improve cancer prevention and treatment outcomes.

Exposure to toluene diisocyanate induces dysbiosis of gut-lung homeostasis: Involvement of gut microbiota

Toluene diisocyanate (TDI) is a major industrial compound that induces occupational asthma with steroid-resistant properties. Recent studies suggest that the gastrointestinal tract may be an effective target for the treatment of respiratory diseases. However, the alterations of the gut-lung axis in TDI-induced asthma remain unexplored. Therefore, in this study, a model of stable occupational asthma caused by TDI exposure was established to detect the alteration of the gut-lung axis. Exposure to TDI resulted in dysbiosis of the gut microbiome, with significant decreases in Barnesiella_intestinihominis, Faecalicoccus_pleomorphus, Lactobacillus_apodemi, and Lactobacillus_intestinalis, but increases in Alistipes_shahii and Odoribacter_laneus. The largest change in abundance was in Barnesiella_intestinihominis, which decreased from 12.14 per cent to 6.18 per cent. The histopathological abnormalities, including shorter length of intestinal villi, thinner thickness of muscularis, reduced number of goblet cells and inflammatory cell infiltration, were found in TDI-treated mice compared to control mice. In addition, increased permeability (evidenced by significantly reduced levels of ZO-1, Occludin and Claudin-1) and activation of TLR4/NF-κB signaling were observed in the intestine of these TDI-exposed mice. Concurrently, exposure to TDI resulted in airway hyperresponsiveness, overt cytokine production (e.g., IL-4, IL-5, IL-13, IL-25, and IL-33), and elevated IgE level within the respiratory tract. The expression of tight junction proteins is reduced and TLR4/NF-κB signaling is activated in the lung following TDI treatment. In addition, correlation analyses showed that changes in the gut microbiota were correlated with TDI exposure-induced airway inflammation. In conclusion, the present study suggests that the immune gut-lung axis may be involved in the development of TDI-induced asthma, which may have implications for potential interventions against steroid-resistant asthma.

Acarbose impairs gut Bacteroides growth by targeting intracellular glucosidases

Acarbose is a type 2 diabetes medicine that prevents dietary starch breakdown into glucose by inhibiting host amylase and glucosidase enzymes. Numerous gut species in the Bacteroides genus enzymatically break down starch and change in relative abundance within the gut microbiome in acarbose-treated individuals. To mechanistically explain this observation, we used two model starch-degrading Bacteroides, Bacteroides ovatus (Bo), and Bacteroides thetaiotaomicron (Bt). Bt growth on starch polysaccharides is severely impaired by acarbose, whereas Bo growth is much less affected by the drug. The Bacteroides use a starch utilization system (Sus) to grow on starch. We hypothesized that Bo and Bt Sus enzymes are differentially inhibited by acarbose. Instead, we discovered that although acarbose primarily targets the Sus periplasmic GH97 enzymes in both organisms, the drug affects starch processing at multiple other points. Acarbose competes for transport through the TonB-dependent SusC proteins and binds to the Sus transcriptional regulators. Furthermore, Bo expresses a non-Sus GH97 (BoGH97D) when grown in starch with acarbose. The Bt homolog, BtGH97H, is not expressed in the same conditions, nor can overexpression of BoGH97D complement the Bt growth inhibition in the presence of acarbose. This work informs us about unexpected complexities of Sus function and regulation in Bacteroides, including variation between related species. Furthermore, this indicates that the gut microbiome may be a source of variable response to acarbose treatment for diabetes.

IMPORTANCE

Acarbose is a type 2 diabetes medication that works primarily by stopping starch breakdown into glucose in the small intestine. This is accomplished by the inhibition of host enzymes, leading to better blood sugar control via reduced ability to derive glucose from dietary starches. The drug and undigested starch travel to the large intestine where acarbose interferes with the ability of some bacteria to grow on starch. However, little is known about how gut bacteria interact with acarbose, including microbes that can use starch as a carbon source. Here, we show that two gut species, Bacteroides ovatus (Bo) and Bacteroides thetaiotaomicron (Bt), respond differently to acarbose: Bt growth is inhibited by acarbose, while Bo growth is less affected. We reveal a complex set of mechanisms involving differences in starch import and sensing behind the different Bo and Bt responses. This indicates the gut microbiome may be a source of variable response to acarbose treatment for diabetes via complex mechanisms in common gut microbes.

Inflammation Mediated by Gut Microbiome Alterations Promotes Lung Cancer Development and an Immunosuppressed Tumor Microenvironment

Accumulating evidence indicates that the gut microbiome influences cancer progression and therapy. We recently showed that progressive changes in gut microbial diversity and composition are closely coupled with tobacco-associated lung adenocarcinoma in a human-relevant mouse model. Furthermore, we demonstrated that the loss of the antimicrobial protein Lcn2 in these mice exacerbates protumor inflammatory phenotypes while further reducing microbial diversity. Yet, how gut microbiome alterations impinge on lung adenocarcinoma development remains poorly understood. In this study, we investigated the role of gut microbiome changes in lung adenocarcinoma development using fecal microbiota transfer and delineated a pathway by which gut microbiome alterations incurred by loss of Lcn2 fostered the proliferation of proinflammatory bacteria of the genus Alistipes, triggering gut inflammation. This inflammation propagated systemically, exerting immunosuppression within the tumor microenvironment, augmenting tumor growth through an IL6-dependent mechanism and dampening response to immunotherapy. Corroborating our preclinical findings, we found that patients with lung adenocarcinoma with a higher relative abundance of Alistipes species in the gut showed diminished response to neoadjuvant immunotherapy. These insights reveal the role of microbiome-induced inflammation in lung adenocarcinoma and present new potential targets for interception and therapy.

Significant difference in gut microbiota Bifidobacterium species but not Lactobacillus species in colorectal cancer patients in comparison with healthy volunteers using quantitative real-time PCR

BACKGROUND

Colorectal cancer (CRC), with a growing incidence trend, is one of the most diagnosed cancers and the second cause of cancer-related deaths worldwide. The literature has frequently focused attention on the correlation between the gut microbiota imbalance and CRC. The genera Lactobacillus and Bifidobacterium have recently received increasing attention because of their potential in restoring alterations in the gut microflora. Therefore, this study aimed to quantitatively evaluate the presence of lactobacilli and bifidobacterial strains in the fecal samples of CRC patients compared to healthy volunteers.

METHODS

From 2018 to 2019, 25 confirmed CRC patients and 25 age- and gender-matched control subjects were enrolled in the study. Bacterial DNA was extracted from the fecal samples and the presence of lactobacilli and bifidobacterial strains were quantitatively determined using quantitative real-time PCR using genus-specific 16S rDNA primers.

RESULTS

A significant decline in the abundance of bifidobacteria in CRC patients compared to healthy individuals (p value<0.003) was observed; however, no significant difference was observed between the two groups regarding the abundance of lactobacilli (p value<0.163). Correlation analysis showed a positive association between the lack of genetic history of CRC and the numbers of gut bifidobacteria and lactobacilli.

CONCLUSION

As a putative gut probiotic, depletion of bifidobacteria showed significant correlation to the development and progression of CRC; therefore, therapeutic use of these probiotic bacteria could be considered a possible adjuvant approach in disease management through modulation of the microbiota.

Immune-enhancing effect of Weizmannia coagulans BCG44 and its supernatant on cyclophosphamide-induced immunosuppressed mice and RAW264.7 cells via the modulation of the gut microbiota

We established a model of cyclophosphamide (CTX)-induced immunosuppressed mice and RAW264.7 cells to assess the effectiveness of W. coagulans BCG44 and its supernatant in enhancing immune function and modulating the gut microbiota. W. coagulans BCG44 and its supernatant restored Th17/Treg balance and alleviated gut inflammation by elevating the expression of interleukin-10 (IL-10) and decreasing IL-6 and toll-like receptor 4 (TLR4). Meanwhile, W. coagulans BCG44 and its supernatant downregulated the levels of lipopolysaccharide and D-lactic acid while increasing the expression of tight junction proteins (ZO-1 and occludin) and goblet cells/crypts to ameliorate mucosal damage. W. coagulans BCG44 and its supernatant may restore the gut microbiota in the immunosuppressed mice by regulating keystone species (Lactobacillus and Lachnospiraceae). PICRUSt2 function prediction and BugBase analysis showed that W. coagulans BCG44 and its supernatant significantly down-regulated American trypanosomiasis and potentially_pathogenic. In addition, under normal versus inflamed culture conditions, stimulation of RAW246.7 cells with W. coagulans BCG44 supernatant activated immune response with increasing proliferation ability and the gene expression of IL-10 while decreasing TLR4. Metabolites in the W. coagulans BCG44 supernatant included arginine, tyrosine, solamargine, tryptophan, D-mannose, phenyllactic acid, and arachidonic acid. Collectively, these findings suggested that W. coagulans BCG44 and its supernatant possess potential immunomodulatory activity and modulate gut microbiota dysbiosis in the CTX-induced immunosuppressed mice.

High-throughput drug screening using a library of antibiotics targeting cancer cell lines that are resistant and sensitive to gemcitabine

Gemcitabine is a nucleoside analog widely used as an anticancer agent against several types of cancer. Although gemcitabine sometimes shows excellent effectiveness, cancer cells are often poorly responsive to or resistant to the drug. Recently, specific strains or dysbiosis of the human microbiome were correlated with drug reactivity and resistance acquisition. Therefore, we aimed to identify antibiotic compounds that can modulate the microbiome to enhance the responsiveness to gemcitabine. To achieve this, we confirmed the gemcitabine responsiveness based on public data and conducted drug screening on a set of 250 antibiotics compounds. Subsequently, we performed experiments to investigate whether the selected compounds could enhance the responsiveness to gemcitabine. First, we grouped a total of seven tumor cell lines into resistant and sensitive group based on the IC50 value (1 μM) of gemcitabine obtained from the public data. Second, we performed high-throughput screening with compound treatments, identifying seven compounds from the resistant group and five from the sensitive group based on dose dependency. Finally, the combination of the selected compound, puromycin dihydrochloride, with gemcitabine in gemcitabine-resistant cell lines resulted in extensive cell death and a significant increase in cytotoxic efficacy. Additionally, mRNA levels associated with cell viability and stemness were reduced. Through this study, we screened antibiotics to further improve the efficacy of existing anticancer drugs and overcome resistance. By combining existing anticancer agents and antibiotic substances, we hope to establish various drug combination therapies and ultimately improve cancer treatment efficacy.

Modulation of host N6-methyladenosine modification by gut microbiota in colorectal cancer

As a research hotspot in the field of molecular biology, N6-methyladenosine (m6A) modification has made progress in the treatment of colorectal cancer (CRC), leukemia and other cancers. Numerous studies have demonstrated that the tumour microenvironment (TME) regulates the level of m6A modification in the host and activates a series of complex epigenetic signalling pathways through interactions with CRC cells, thus affecting the progression and prognosis of CRC. However, with the diversity in the composition of TME factors, this action is reciprocal and complex. Encouragingly, some studies have experimentally revealed that the intestinal flora can alter CRC cell proliferation by directly acting on m6A and thereby altering CRC cell proliferation. This review summarizes the data, supporting the idea that the intestinal flora can influence host m6A levels through pathways such as methyl donor metabolism and thus affect the progression of CRC. We also review the role of m6A modification in the diagnosis, treatment, and prognostic assessment of CRC and discuss the current status, limitations, and potential clinical value of m6A modification in this field. We propose that additional in-depth research on m6A alterations in CRC patients and their TME-related targeted therapeutic issues will lead to better therapeutic outcomes for CRC patients.

Genomic analysis of Enterobacteriaceae from colorectal cancer patients at a tertiary hospital in Ghana: a case-control study

Colorectal cancer (CRC) is a severe gastrointestinal cancer and a leading cause of cancer-related deaths in Ghana. The potential role of gut Enterobacteriaceae in the increasing incidence of CRC in Ghana is yet to be thoroughly investigated. In this study, Enterobacteriaceae from CRC patients and healthy control participants were analyzed by whole genome sequencing to identify genomic features that are associated with CRC. Socio-demographic data showed a significant association between age and alcohol consumption and CRC. Escherichia coli was the most abundant Enterobacteriaceae isolated from the study participants and they were predominantly intestinal commensals. Escherichia coli isolates belonging to phylogroup D encoded the highest number of virulence genes. The agn43 and int genes were widespread in Escherichia coli isolates from the CRC patients. Multilocus sequence types of potentially pathogenic Escherichia coli from the CRC patients also encoded genes involved in aggregation, adherence and biofilm formation. The ampC2 and ampH antimicrobial resistance genes were also widespread in the genome of the Escherichia coli isolates. This study highlights the virulence tendencies of Escherichia coli from CRC patients and their ability to transfer virulence determinants to other Enterobacteriaceae residing in the gut.

High sucrose diet-induced abnormal lipid metabolism in mice is related to the dysbiosis of gut microbiota

BACKGROUND & AIMS

Excess sucrose intake induces metabolic syndrome. In human, abnormal lipids metabolism like obesity, hyperlipidemia and fatty liver are induced. However, excess sucrose causes different phenotypes in different species. Based on our previous study, excess sucrose induced fatty liver and hyperlipidemia in rats. The phenotypes and mechanism of abnormal lipid metabolism in mice is unclear. We investigated the different phenotypes in 5 strains of mice and the relationship between gut microbiome and abnormal lipid metabolism in C57BL/6N mice.

METHODS

We examined the effect of a high sucrose diet in 5 different strains of mice. Besides, to find out the relationship between gut microbiome and metabolic disorder induced by excess sucrose, C57BL/6N mice were fed with a high sucrose diet with or without antibiotics cocktail.

RESULTS

A high sucrose diet induced obesity and fatty liver in inbred mice, whereas did not induce hyperlipidemia in all strains of mice. Moreover, a high sucrose diet changed the composition of gut microbiota in C57BL/6N mice. Antibiotics treatment alleviated the abnormal lipid metabolism induced by high sucrose diet by changing the composition of gut short chain fatty acids.

CONCLUSIONS

These results indicates that the phenotypes of metabolic syndrome are influenced by genetic factors. Furthermore, the dysbiosis of gut microbiome caused by excess sucrose may contribute to the development of abnormal lipid metabolism via its metabolites.

Integration of microbiome, metabolomics and transcriptome for in-depth understanding of berberine attenuates AOM/DSS-induced colitis-associated colorectal cancer

A type of colorectal cancer (CRC)，Colitis-associated colorectal cancer (CAC)， is closely associated with chronic inflammation and gut microbiota dysbiosis. Berberine (BBR) has a long history in the treatment of intestinal diseases, which has been reported to inhibit colitis and CRC. However, the mechanism of its action is still unclear. Here, this study aimed to explore the potential protective effects of BBR on azoxymethane (AOM)/dextransulfate sodium (DSS)-induced colitis and tumor mice, and to elucidate its potential molecular mechanisms by microbiota, genes and metabolic alterations. The results showed that BBR inhibited the gut inflammation and improved the function of mucosal barrier to ameliorate AOM/DSS-induced colitis. And BBR treatment significantly reduced intestinal tumor development and ki-67 expression of intestinal tissue along with promoted apoptosis. Through microbiota analysis based on the 16 S rRNA gene, we found that BBR treatment improved intestinal microbiota imbalance in AOM/DSS-induced colitis and tumor mice, which were characterized by an increase of beneficial bacteria, for instance Akkermanisa, Lactobacillus, Bacteroides uniformis and Bacteroides acidifaciens. In addition, transcriptome analysis showed that BBR regulated colonic epithelial signaling pathway in CAC mice particularly by tryptophan metabolism and Wnt signaling pathway. Notably, BBR treatment resulted in the enrichment of amino acids metabolism and microbiota-derived SCFA metabolites. In summary, our research findings suggest that the gut microbiota-amino acid metabolism-Wnt signaling pathway axis plays critical role in maintaining intestinal homeostasis, which may provide new insights into the inhibitory effects of BBR on colitis and colon cancer.

Inorganic Polyphosphate Promotes Colorectal Cancer Growth via TRPM8 Receptor Signaling Pathway

BACKGROUND

Colorectal cancer (CRC) is characterized by a pro-inflammatory microenvironment and features high-energy-supply molecules that assure tumor growth. A still less studied macromolecule is inorganic polyphosphate (iPolyP), a high-energy linear polymer that is ubiquitous in all forms of life. Made up of hundreds of repeated orthophosphate units, iPolyP is essential for a wide variety of functions in mammalian cells, including the regulation of proliferative signaling pathways. Some evidence has suggested its involvement in carcinogenesis, although more studies need to be pursued. Moreover, iPolyP regulates several homeostatic processes in animals, spanning from energy metabolism to blood coagulation and tissue regeneration.

RESULTS

In this study, we tested the role of iPolyP on CRC proliferation, using in vitro and ex vivo approaches, in order to evaluate its effect on tumor growth. We found that iPolyP is significantly increased in tumor tissues, derived from affected individuals enrolled in this study, compared to the corresponding peritumoral counterparts. In addition, iPolyP signaling occurs through the TRPM8 receptor, a well-characterized Na+ and Ca2+ ion channel often overexpressed in CRC and linked with poor prognosis, thus promoting CRC cell proliferation. The pharmacological inhibition of TRPM8 or RNA interference experiments performed in established CRC cell lines, such as Caco-2 and SW620, showed that the involvement of TRPM8 is essential, greater than that of the other two known iPolyP receptors, P2Y1 and RAGE. The presence of iPolyP drives cancer cells towards the mitotic phase of the cell cycle by enhancing the expression of ccnb1, which encodes the Cyclin B protein. In vitro 2D and 3D data reflected the ex vivo results, obtained by the generation of CRC-derived organoids, which increased in size.

CONCLUSIONS

These results indicate that iPolyP may be considered a novel and unexpected early biomarker supporting colorectal cancer cell proliferation.

Personalised medicine based on host genetics and microbiota applied to colorectal cancer

Colorectal cancer (CRC) ranks second in incidence and third in cancer mortality worldwide. This situation, together with the understanding of the heterogeneity of the disease, has highlighted the need to develop a more individualised approach to its prevention, diagnosis and treatment through personalised medicine. This approach aims to stratify patients according to risk, predict disease progression and determine the most appropriate treatment. It is essential to identify patients who may respond adequately to treatment and those who may be resistant to treatment to avoid unnecessary therapies and minimise adverse side effects. Current research is focused on identifying biomarkers such as specific mutated genes, the type of mutations and molecular profiles critical for the individualisation of CRC diagnosis, prognosis and treatment guidance. In addition, the study of the intestinal microbiota as biomarkers is being incorporated due to the growing scientific evidence supporting its influence on this disease. This article comprehensively addresses the use of current and emerging diagnostic, prognostic and predictive biomarkers in precision medicine against CRC. The effects of host genetics and gut microbiota composition on new approaches to treating this disease are discussed. How the gut microbiota could mitigate the side effects of treatment is reviewed. In addition, strategies to modulate the gut microbiota, such as dietary interventions, antibiotics, and transplantation of faecal microbiota and phages, are discussed to improve CRC prevention and treatment. These findings provide a solid foundation for future research and improving the care of CRC patients.

Disparity in trends and characteristics of early onset colorectal cancer: analysis from the National Inpatient Sample, 2016 to 2021

Introduction

Colon cancer is the second most common cause of death in the United States. With an increasing number of patients diagnosed at younger ages, the disease remains a significant burden. However, recent data on early onset patients admitted with colon cancer are still limited.

Methods

We utilized the 2016 to 2021 National Inpatient Sample to investigate trends and characteristics of colon cancer hospitalizations. Nonelective participants were divided into early onset and normal-age groups, with a cut point of 50 years old. In addition, we also investigated factors associated with the risk of inpatient mortality in the study population.

Results

There were 26,903 early onset nonelective colon cancer hospitalizations in the population group, amounting to 11.91% of total colon cancer hospitalizations. No significant changes or trends were seen from 2016 to 2021. Compared to the normal-age population group, there was a disproportionate number of Blacks, Hispanics, and Asian Americans, as well as those with obesity and tobacco usage.

Conclusion

Some demographic factors and comorbidities disproportionately affect early onset colon cancer patients when compared to the normal-age population group. Further investigations are necessary to combat the growing incidence of early onset colon cancer.

Metabolic determinants of leukemia onset variability in genetically homogeneous AKR mice

Leukemia is a complex disease shaped by the intricate interplay of genetic and environmental factors. Given our preliminary data showing different leukemia incidence in genetically homogenous AKR mice harboring the spontaneous leukemia-inducing mutation Rmcfs, we sought to unravel the role of metabolites and gut microbiota in the leukemia penetrance. Our metabolomic analysis revealed distinct serum metabolite profiles between mice that developed leukemia and those that did not. We discovered that linoleic acid (LA), an essential ω-6 polyunsaturated fatty acid, was significantly decreased in the leukemia group, with the lower levels observed starting from 25 weeks before the onset. A predictive model based on LA levels demonstrated high accuracy in predicting leukemia development (area under curve 0.82). In vitro experiment confirmed LA's cytotoxic effects against leukemia cells, and in vivo study showed that a diet enriched with LA prolonged survival in AKR mice. Furthermore, gut microbiome analysis identified specific Lachnospiraceae species, that affect host lipid metabolism, are exclusively present in the leukemia group, suggesting their potential influence on LA metabolism and leukemia development. These findings shed light on the complex relationship between metabolites, gut microbiota, and leukemia development, providing valuable insights into the role of non-genetic factors in leukemia penetrance and potential strategies for leukemia prevention.

Role of Gut Microbiota in Predisposition to Colon Cancer: A Narrative Review

Globally, colorectal cancer (CRC) is a leading cause of cancer-related mortality. Dietary habits, inflammation, hereditary characteristics, and gut microbiota are some of its causes. The gut microbiota, a diverse population of bacteria living in the digestive system, has an impact on a variety of parameters, including inflammation, DNA damage, and immune response. The gut microbiome has a significant role in colon cancer susceptibility. Many studies have highlighted dysbiosis, an imbalance in the gut microbiota's makeup, as a major factor in colon cancer susceptibility. Dysbiosis has the potential to produce toxic metabolites and pro-inflammatory substances, which can hasten the growth of tumours. The ability of the gut microbiota to affect the host's immune system can also influence whether cancer develops or not. By better comprehending these complex interactions between colon cancer predisposition and gut flora, new preventive and therapeutic techniques might be developed. Targeting the gut microbiome with dietary modifications, probiotics, or faecal microbiota transplantation may offer cutting-edge approaches to reducing the risk of colon cancer and improving patient outcomes. The complex connection between the makeup of the gut microbiota and the emergence of colorectal cancer is explored in this narrative review.

Gut microbiota derived short-chain fatty acids in physiology and pathology: An update

Short-chain fatty acids (SCFAs) are essential molecules produced by gut bacteria that fuel intestinal cells and may also influence overall health. An imbalance of SCFAs can result in various acute and chronic diseases, including diabetes, obesity and colorectal cancer (CRC). This review delves into the multifaceted roles of SCFAs, including a brief discussion on their source and various gut-residing bacteria. Primary techniques used for detection of SCFAs, including gas chromatography, high-performance gas chromatography, nuclear magnetic resonance and capillary electrophoresis are also discussed through this article. This review study also compiles various synthesis pathways of SCFAs from diverse substrates such as sugar, acetone, ethanol and amino acids. The different pathways through which SCFAs enter cells for immune response regulation are also highlighted. A major emphasis is the discussion on diseases associated with SCFA dysregulation, such as anaemia, brain development, CRC, depression, obesity and diabetes. This includes exploring the relationship between SCFA levels across ethnicities and their connection with blood pressure and CRC. In conclusion, this review highlights the critical role of SCFAs in maintaining gut health and their implications in various diseases, emphasizing the need for further research on SCFA detection, synthesis and their potential as diagnostic biomarkers. Future studies of SCFAs will pave the way for the development of novel diagnostic tools and therapeutic strategies for optimizing gut health and preventing diseases associated with SCFA dysregulation.

Symbiotic symphony: Understanding host-microbiota dialogues in a spatial context

Modern precision sequencing techniques have established humans as a holobiont that live in symbiosis with the microbiome. Microbes play an active role throughout the life of a human ranging from metabolism and immunity to disease tolerance. Hence, it is of utmost significance to study the eukaryotic host in conjunction with the microbial antigens to obtain a complete picture of the host-microbiome crosstalk. Previous attempts at profiling host-microbiome interactions have been either superficial or been attempted to catalogue eukaryotic transcriptomic profile and microbial communities in isolation. Additionally, the nature of such immune-microbial interactions is not random but spatially organised. Hence, for a holistic clinical understanding of the interplay between hosts and microbiota, it's imperative to concurrently analyze both microbial and host genetic information, ensuring the preservation of their spatial integrity. Capturing these interactions as a snapshot in time at their site of action has the potential to transform our understanding of how microbes impact human health. In examining early-life microbial impacts, the limited presence of communities compels analysis within reduced biomass frameworks. However, with the advent of spatial transcriptomics we can address this challenge and expand our horizons of understanding these interactions in detail. In the long run, simultaneous spatial profiling of host-microbiome dialogues can have enormous clinical implications especially in gaining mechanistic insights into the disease prognosis of localised infections and inflammation. This review addresses the lacunae in host-microbiome research and highlights the importance of profiling them together to map their interactions while preserving their spatial context.

IL-1β mediates Candida tropicalis-induced immunosuppressive function of MDSCs to foster colorectal cancer

BACKGROUND

There is increasing evidence that gut fungi dysbiosis plays a crucial role in the development and progression of colorectal cancer (CRC). It has been reported that gut fungi exacerbate the severity of CRC by regulating tumor immunity. Our previous studies have shown that the opportunistic pathogenic fungal pathogen, Candida tropicalis (C. tropicalis) promotes CRC progression by enhancing the immunosuppressive function of MDSCs and activating the NLRP3 inflammasome of MDSCs. However, the relationship between IL-1β produced by NLRP3 inflammasome activation and the immunosuppressive function of MDSCs enhanced by C. tropicalis in CRC remains unclear.

METHODS

The TCGA database was used to analyze the relationship between IL-1β and genes related to immunosuppressive function of MDSCs in human CRC. The expression of IL-1β in human CRC tissues was detected by immunofluorescence staining. The proteomic analysis was performed on the culture supernatant of C. tropicalis-stimulated MDSCs. The experiments of supplementing and blocking IL-1β as well as inhibiting the NLRP3 inflammasome activation were conducted. A mouse colon cancer xenograft model was established by using MC38 colon cancer cell line.

RESULTS

Analysis of CRC clinical samples showed that the high expression of IL-1β was closely related to the immunosuppressive function of tumor-infiltrated MDSCs. The results of in vitro experiments revealed that IL-1β was the most secreted cytokine of MDSCs stimulated by C. tropicalis. In vitro supplementation of IL-1β further enhanced the immunosuppressive function of C. tropicalis-stimulated MDSCs and NLRP3-IL-1β axis mediated the immunosuppressive function of MDSCs enhanced by C. tropicalis. Finally, blockade of IL-1β secreted by MDSCs augmented antitumor immunity and mitigated C. tropicalis-associated colon cancer.

CONCLUSIONS

C. tropicalis promotes excessive secretion of IL-1β from MDSCs via the NLRP3 inflammasome. IL-1β further enhances the immunosuppressive function of MDSCs to inhibit antitumor immunity, thus promoting the progression of CRC. Therefore, targeting IL-1β secreted by MDSCs may be a potential immunotherapeutic strategy for the treatment of CRC.

Mechanism of probiotics in the intervention of colorectal cancer: a review

The human microbiome interacts with the host mainly in the intestinal lumen, where putrefactive bacteria are suggested to promote colorectal cancer (CRC). In contrast, probiotics and their isolated components and secreted substances, display anti-tumor properties due to their ability to modulate gut microbiota composition, promote apoptosis, enhance immunity, resist oxidation and alter metabolism. Probiotics help to form a solid intestinal barrier against damaging agents via altering the gut microbiota and preventing harmful microbes from colonization. Probiotic strains that specifically target essential proteins involved in the process of apoptosis can overcome CRC resistance to apoptosis. They can increase the production of anti-inflammatory cytokines, essential in preventing carcinogenesis, and eliminate cancer cells by activating T cell-mediated immune responses. There is a clear indication that probiotics optimize the antioxidant system, decrease radical generation, and detect and degrade potential carcinogens. In this review, the pathogenic mechanisms of pathogens in CRC and the recent insights into the mechanism of probiotics in CRC prevention and therapy are discussed to provide a reference for the actual application of probiotics in CRC.

The Effects of Aspirin Intervention on Inflammation-Associated Lingual Bacteria: A Pilot Study from a Randomized Clinical Trial

Several bacterial taxa enriched in inflammatory bowel diseases and colorectal cancer (CRC) are found in the oral cavity. We conducted a pilot study nested within a six-week aspirin intervention in a randomized placebo-controlled trial to test their response to aspirin intervention. Fifty healthy subjects, 50-75 years old, were randomized to receive 325 mg aspirin (n = 30) or placebo (n = 20) orally once daily for six weeks. Oral tongue swabs were collected at baseline and week six. We estimated the association between aspirin use and the temporal changes in the relative abundance of pre-specified genus level taxa from pre- to post-treatment. The temporal change in relative abundance differed for eight genus level taxa between the aspirin and placebo groups. In the aspirin group, there were significant increases in the relative abundances of Neisseria, Streptococcus, Actinomyces, and Rothia and significant decreases in Prevotella, Veillonella, Fusobacterium, and Porphyromonas relative to placebo. The log ratio of Neisseria to Fusobacterium declined more in the aspirin group than placebo, signaling a potential marker associated with aspirin intervention. These preliminary findings should be validated using metagenomic sequencing and may guide future studies on the role of aspirin on taxa in various oral ecological niches.

A Critical Review on Akkermansia muciniphila: Functional Mechanisms, Technological Challenges, and Safety Issues

Due to its physiological benefits from in vitro and in vivo points of view, Akkermansia muciniphila, a common colonizer in the human gut mucous layer, has consistently been identified as an option for the next-generation probiotic. A. muciniphila is a significant bacterium that promotes host physiology. However, it also has a great deal of potential to become a probiotic due to its physiological advantages in a variety of therapeutic circumstances. Therefore, it can be established that the abundance of A. muciniphila in the gut environment, which is controlled by many genetic and dietary variables, is related to the biological behaviors of the intestinal microbiota and gut dysbiosis/eubiosis circumstances. Before A. muciniphila is widely utilized as a next-generation probiotic, regulatory obstacles, the necessity for significant clinical trials, and the sustainability of manufacturing must be eliminated. In this review, the outcomes of recent experimental and clinical reports are comprehensively reviewed, and common colonization patterns, main factors involved in the colonization of A. muciniphila in the gut milieu, their functional mechanisms in establishing homeostasis in the metabolic and energy pathways, the promising delivery role of microencapsulation, potential genetic engineering strategies, and eventually safety issues of A. muciniphila have been discussed.

Microbiota and detrimental protein derived metabolites in colorectal cancer

Colorectal cancer (CRC) is the third leading cancer in incidence and the second leading cancer in mortality worldwide. There is growing scientific evidence to support the crucial role of the gut microbiota in the development of CRC. The gut microbiota is the complex community of microorganisms that inhabit the host gut in a symbiotic relationship. Diet plays a crucial role in modulating the risk of CRC, with a high intake of red and processed meat being a risk factor for the development of CRC. The production of metabolites derived from protein fermentation by the gut microbiota is considered a crucial element in the interaction between red and processed meat consumption and the development of CRC. This paper examines several metabolites derived from the bacterial fermentation of proteins associated with an increased risk of CRC. These metabolites include ammonia, polyamines, trimethylamine N-oxide (TMAO), N-nitroso compounds (NOC), hydrogen sulphide (H2S), phenolic compounds (p-cresol) and indole compounds (indolimines). These compounds are depicted and reviewed for their association with CRC risk, possible mechanisms promoting carcinogenesis and their relationship with the gut microbiota. Additionally, this paper analyses the evidence related to the role of red and processed meat intake and CRC risk and the factors and pathways involved in bacterial proteolytic fermentation in the large intestine.

Unlocking the potential of flavonoids: Natural solutions in the fight against colon cancer

Colorectal cancer (CRC) is a major cause of cancer-related deaths worldwide, underscoring the importance of understanding the diverse molecular and genetic underpinnings of CRC to improve its diagnosis, prognosis, and treatment. This review delves into the adenoma-carcinoma-metastasis model, emphasizing the "APC-KRAS-TP53" signature events in CRC development. CRC is categorized into four consensus molecular subtypes, each characterized by unique genetic alterations and responses to therapy, illustrating its complexity and heterogeneity. Furthermore, we explore the role of chronic inflammation and the gut microbiome in CRC progression, emphasizing the potential of targeting these factors for prevention and treatment. This review discusses the impact of dietary carcinogens and lifestyle factors and the critical role of early detection in improving outcomes, and also examines conventional chemotherapy options for CRC and associated challenges. There is significant focus on the therapeutic potential of flavonoids for CRC management, discussing various types of flavonoids, their sources, and mechanisms of action, including their antioxidant properties, modulation of cell signaling pathways, and effects on cell cycle and apoptosis. This article presents evidence of the synergistic effects of flavonoids with conventional cancer therapies and their role in modulating the gut microbiome and immune response, thereby offering new avenues for CRC treatment. We conclude by emphasizing the importance of a multidisciplinary approach to CRC research and treatment, incorporating insights from genetic, molecular, and lifestyle factors. Further research is needed on the preventive and therapeutic potential of natural compounds, such as flavonoids, in CRC, underscoring the need for personalized and targeted treatment strategies.

Role of Native Probiotic Lactobacillus Species via TGF-β Signaling Pathway Modulation in CRC

Background

Colon microbiome composition in colorectal cancer (CRC) patients undergoes remarkable changes. The present study was designed to assess the impact of Lactobacillus mixture on the regulating the CRC by influencing the transforming growth factor beta (TGF-β) signaling pathway in both in vitro (HT-29 cancer cells) and in vivo (BALB/c mice) models.

Methods

In this study, the antiproliferative effect of a native potential probiotic Lactobacillus mixture on HT-29 cancer cells was evaluated using the MTT assay method. Also, qRT-PCR was performed to assess the RNA expression level of genes associated with the TGF-β signaling pathway at three levels: receptor, regulatory, and inhibitory SMADs. Finally, the in vivo assays were investigated by three groups of mice: a naive group (PBS), a disease group (azoxymethane [AOM]/ dextran sulfate sodium [DSS] + PBS), and a treatment group (AOM/DSS + Lactobacillus mixture in PBS).

Results

The MTT results showed a significant decrease in proliferation of HT-29 cancer cells after 120 h of treatment. Furthermore, qRT-PCR demonstrated the downregulation of the smad2/3 gene expression in HT-29-treated cells and also reduction in the level of smad4 gene expression. In addition, in the mouse model, the tgf-βR1 gene was downregulated in the group treated with AOM/DSS/Lactobacillus, but not the AOM/DSS group. A downregulation of smad4 gene expression was also observed in in vivo models.

Conclusion

The obtained results suggest that our novel probiotic Lactobacillus mixture could have a positive impact on the inhibition of the CRC progression by downregulating the TGF-β signaling pathway.

Acarbose Impairs Gut Bacteroides Growth by Targeting Intracellular GH97 Enzymes

Acarbose is a type-2 diabetes medicine that inhibits dietary starch breakdown into glucose by inhibiting host amylase and glucosidase enzymes. Numerous gut species in the Bacteroides genus enzymatically break down starch and change in relative abundance within the gut microbiome in acarbose-treated individuals. To mechanistically explain this observation, we used two model starch-degrading Bacteroides, Bacteroides ovatus (Bo) and Bacteroides thetaiotaomicron (Bt). Bt growth is severely impaired by acarbose whereas Bo growth is not. The Bacteroides use a starch utilization system (Sus) to grow on starch. We hypothesized that Bo and Bt Sus enzymes are differentially inhibited by acarbose. Instead, we discovered that although acarbose primarily targets the Sus periplasmic GH97 enzymes in both organisms, the drug affects starch processing at multiple other points. Acarbose competes for transport through the Sus beta-barrel proteins and binds to the Sus transcriptional regulators. Further, Bo expresses a non-Sus GH97 (BoGH97D) when grown in starch with acarbose. The Bt homolog, BtGH97H, is not expressed in the same conditions, nor can overexpression of BoGH97D complement the Bt growth inhibition in the presence of acarbose. This work informs us about unexpected complexities of Sus function and regulation in Bacteroides, including variation between related species. Further, this indicates that the gut microbiome may be a source of variable response to acarbose treatment for diabetes.

Exploring Gut Microbiome Composition and Circulating Microbial DNA Fragments in Patients with Stage II/III Colorectal Cancer: A Comprehensive Analysis

BACKGROUND

Colorectal cancer (CRC) significantly contributes to cancer-related mortality, necessitating the exploration of prognostic factors beyond TNM staging. This study investigates the composition of the gut microbiome and microbial DNA fragments in stage II/III CRC.

METHODS

A cohort of 142 patients with stage II/III CRC and 91 healthy controls underwent comprehensive microbiome analysis. Fecal samples were collected for 16S rRNA sequencing, and blood samples were tested for the presence of microbial DNA fragments. De novo clustering analysis categorized individuals based on their microbial profiles. Alpha and beta diversity metrics were calculated, and taxonomic profiling was conducted.

RESULTS

Patients with CRC exhibited distinct microbial composition compared to controls. Beta diversity analysis confirmed CRC-specific microbial profiles. Taxonomic profiling revealed unique taxonomies in the patient cohort. De novo clustering separated individuals into distinct groups, with specific microbial DNA fragment detection associated with certain patient clusters.

CONCLUSIONS

The gut microbiota can differentiate patients with CRC from healthy individuals. Detecting microbial DNA fragments in the bloodstream may be linked to CRC prognosis. These findings suggest that the gut microbiome could serve as a prognostic factor in stage II/III CRC. Identifying specific microbial markers associated with CRC prognosis has potential clinical implications, including personalized treatment strategies and reduced healthcare costs. Further research is needed to validate these findings and uncover underlying mechanisms.

Role of Probiotics in Gut Microbiome and Metabolome in Non-Alcoholic Fatty Liver Disease Mouse Model: A Comparative Study

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver condition worldwide. Numerous studies conducted recently have demonstrated a connection between the dysbiosis of the development of NAFLD and gut microbiota. Rebuilding a healthy gut ecology has been proposed as a strategy involving the use of probiotics. The purpose of this work is to investigate and compare the function of probiotics Akkermansia muciniphila (A. muciniphila) and VSL#3 in NAFLD mice. Rodent NAFLD was modeled using a methionine choline-deficient diet (MCD) with/without oral probiotic delivery. Subsequently, qPCR, histological staining, and liver function tests were conducted. Mass spectrometry-based analysis and 16S rDNA gene sequencing were used to investigate the liver metabolome and gut microbiota. We found that while both A. muciniphila and VSL#3 reduced hepatic fat content, A. muciniphila outperformed VSL#3. Furthermore, probiotic treatment restored the β diversity of the gut flora and A. muciniphila decreased the abundance of pathogenic bacteria such as Ileibacterium valens. These probiotics altered the metabolism in MCD mice, especially the glycerophospholipid metabolism. In conclusion, our findings distinguished the role of A. muciniphila and VSL#3 in NAFLD and indicated that oral-gavage probiotics remodel gut microbiota and improve metabolism, raising the possibility of using probiotics in the cure of NAFLD.

E4BP4 in macrophages induces an anti-inflammatory phenotype that ameliorates the severity of colitis

Macrophages are versatile cells of the innate immune system that work by altering their pro- or anti-inflammatory features. Their dysregulation leads to inflammatory disorders such as inflammatory bowel disease. We show that macrophage-specific upregulation of the clock output gene and transcription factor E4BP4 reduces the severity of colitis in mice. RNA-sequencing and single-cell analyses of macrophages revealed that increased expression of E4BP4 leads to an overall increase in expression of anti-inflammatory genes including Il4ra with a concomitant reduction in pro-inflammatory gene expression. In contrast, knockout of E4BP4 in macrophages leads to increased proinflammatory gene expression and decreased expression of anti-inflammatory genes. ChIP-seq and ATAC-seq analyses further identified Il4ra as a target of E4BP4, which drives anti-inflammatory polarization in macrophages. Together, these results reveal a critical role for E4BP4 in regulating macrophage inflammatory phenotypes and resolving inflammatory bowel diseases.

Gut microbiota and their derivatives in the progression of colorectal cancer: Mechanisms of action, genome and epigenome contributions

Gut microbiota interacts with host epithelial cells and regulates many physiological functions such as genetics, epigenetics, metabolism of nutrients, and immune functions. Dietary factors may also be involved in the etiology of colorectal cancer (CRC), especially when an unhealthy diet is consumed with excess calorie intake and bad practices like smoking or consuming a great deal of alcohol. Bacteria including Fusobacterium nucleatum, Enterotoxigenic Bacteroides fragilis (ETBF), and Escherichia coli (E. coli) actively participate in the carcinogenesis of CRC. Gastrointestinal tract with chronic inflammation and immunocompromised patients are at high risk for CRC progression. Further, the gut microbiota is also involved in Geno-toxicity by producing toxins like colibactin and cytolethal distending toxin (CDT) which cause damage to double-stranded DNA. Specific microRNAs can act as either tumor suppressors or oncogenes depending on the cellular environment in which they are expressed. The current review mainly highlights the role of gut microbiota in CRC, the mechanisms of several factors in carcinogenesis, and the role of particular microbes in colorectal neoplasia.

Bifidobacterium breve-derived indole-3-lactic acid ameliorates colitis-associated tumorigenesis by directing the differentiation of immature colonic macrophages

Aim: To elucidate dynamics and functions in colonic macrophage subsets, and their regulation by Bifidobacterium breve (B. breve) and its associated metabolites in the initiation of colitis-associated colorectal cancer (CAC). Methods: Azoxymethane (AOM) and dextran sodium sulfate (DSS) were used to create a CAC model. The tumor-suppressive effect of B. breve and variations of macrophage subsets were evaluated. Intestinal macrophages were ablated to determine their role in the protective effects of B. breve. Efficacious molecules produced by B. breve were identified by non-targeted and targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The molecular mechanism was further verified in murine bone marrow-derived macrophages (BMDMs), macrophages derived from human peripheral blood mononuclear cells (hPBMCs), and demonstrated in CAC mice. Results: B. breve alleviated colitis symptoms, delayed colonic tumorigenesis, and promoted phenotypic differentiation of immature inflammatory macrophages into mature homeostatic macrophages. On the contrary, the ablation of intestinal macrophages largely annulled the protective effects of B. breve. Microbial analysis of colonic contents revealed the enrichment of probiotics and the depletion of potential pathogens following B. breve supplementation. Moreover, indole-3-lactic acid (ILA) was positively correlated with B. breve in CAC mice and highly enriched in the culture supernatant of B. breve. Also, the addition of ILA directly promoted AKT phosphorylation and restricted the pro-inflammatory response of murine BMDMs and macrophages derived from hPBMCs in vitro. The effects of ILA in murine BMDMs and macrophages derived from hPBMCs were abolished by the aryl hydrocarbon receptor (AhR) antagonist CH-223191 or the AKT inhibitor MK-2206. Furthermore, ILA could protect against tumorigenesis by regulating macrophage differentiation in CAC mice; the AhR antagonist largely abrogated the effects of B. breve and ILA in relieving colitis and tumorigenesis. Conclusion: B. breve-mediated tryptophan metabolism ameliorates the precancerous inflammatory intestinal milieu to inhibit tumorigenesis by directing the differentiation of immature colonic macrophages.

Antitumor Effect and Gut Microbiota Modulation by Quercetin, Luteolin, and Xanthohumol in a Rat Model for Colorectal Cancer Prevention

Colorectal cancer stands as the third most prevalent form of cancer worldwide, with a notable increase in incidence in Western countries, mainly attributable to unhealthy dietary habits and other factors, such as smoking or reduced physical activity. Greater consumption of vegetables and fruits has been associated with a lower incidence of colorectal cancer, which is attributed to their high content of fiber and bioactive compounds, such as flavonoids. In this study, we have tested the flavonoids quercetin, luteolin, and xanthohumol as potential antitumor agents in an animal model of colorectal cancer induced by azoxymethane and dodecyl sodium sulphate. Forty rats were divided into four cohorts: Cohort 1 (control cohort), Cohort 2 (quercetin cohort), Cohort 3 (luteolin cohort), and Cohort 4 (xanthohumol cohort). These flavonoids were administered intraperitoneally to evaluate their antitumor potential as pharmaceutical agents. At the end of the experiment, after euthanasia, different physical parameters and the intestinal microbiota populations were analyzed. Luteolin was effective in significantly reducing the number of tumors compared to the control cohort. Furthermore, the main significant differences at the microbiota level were observed between the control cohort and the cohort treated with luteolin, which experienced a significant reduction in the abundance of genera associated with disease or inflammatory conditions, such as Clostridia UCG-014 or Turicibacter. On the other hand, genera associated with a healthy state, such as Muribaculum, showed a significant increase in the luteolin cohort. These results underline the anti-colorectal cancer potential of luteolin, manifested through a modulation of the intestinal microbiota and a reduction in the number of tumors.

The role of Akkermansia muciniphila in colorectal cancer: A double-edged sword of treatment or disease progression?

Colorectal cancer (CRC) is the second most cancer-related death worldwide. In recent years, probiotics have been used to reduce the potential risks of CRC and tumors with various mechanisms. Different bacteria have been suggested to play different roles in the progression, prevention, or treatment of CRC. Akkermansia muciniphila is considered a next-generation probiotic for preventing and treating some diseases. Therefore, in this review article, we aimed to describe and discuss different mechanisms of A. muciniphila as an intestinal microbiota or probiotic in CRC. Some studies suggested that the abundance of A. muciniphila was higher or increased in CRC patients compared to healthy individuals. However, the decreased abundance of A. muciniphila was associated with severe symptoms of CRC, indicating that A. muciniphila did not play a role in the development of CRC. In addition, A. muciniphila administration elevates gene expression of proliferation-associated molecules such as S100A9, Dbf4, and Snrpd1, or markers for cell proliferation. Some other studies suggested that inflammation and tumorigenesis in the intestine might promoted by A. muciniphila. Overall, the role of A. muciniphila in CRC development or inhibition is still unclear and controversial. Various methods of bacterial supplementation, such as viability, bacterial number, and abundance, could all influence the colonization effect of A. muciniphila administration and CRC progression. Overall, A. mucinipila has been revealed to modulate the therapeutic potential of immune checkpoint inhibitors. Preliminary human data propose that oral consumption of A. muciniphila is safe, but its efficacy needs to be confirmed in more human clinical studies.

Effect of Lactobacillus Rhamnosus GG for Regulation of Inflammatory Response in Radiation-Induced Enteritis

The purpose of this study was to investigate the role of Lactobacillus rhamnosus GG (LGG) probiotics in radiation enteritis using in vivo mice. A total of 40 mice were randomly assigned to four groups: control, probiotics, radiotherapy (RT), and RT + probiotics. For the group of probiotics, 0.2 mL of solution that contained 1.0 × 108 colony-forming units (CFU) of LGG was used and orally administered daily until sacrifice. For RT, a single dose of 14 Gy was administered using a 6 mega-voltage photon beam to the abdominopelvic area. Mice were sacrifice at day 4 (S1) and day 7 (S2) after RT. Their jejunum, colon, and stool were collected. A multiplex cytokine assay and 16 s ribosomal RNA amplicon sequencing were then performed. Regarding cytokine concentrations in tissues, pro-inflammatory cytokines, such as tumor necrosis factor-α, interleukin-6 and monocyte chemotactic protein-1, showed significantly decreased protein levels in colon tissues of the RT + probiotics group than in the RT alone group (all p < 0.05). As for comparing microbial abundance through alpha-diversity and beta-diversity, no significant differences were observed between the RT + probiotics and RT alone groups, except for an increase in alpha-diversity in the stool of the RT + probiotics group. Upon analysis of differential microbes based on treatment, the dominance of anti-inflammatory-related microbes, such as Porphyromonadaceae, Bacteroides acidifaciens, and Ruminococcus, was observed in the jejunum, colon, and stool of the RT + probiotics group. With regard to predicted metabolic pathway abundances, the pathways associated with anti-inflammatory processes, such as biosynthesis of pyrimidine nucleotides, peptidoglycans, tryptophan, adenosylcobalamin, and propionate, were differentially identified in the RT + probiotics group compared to the RT alone group. Protective effects of probiotics on radiation enteritis were potentially derived from dominant anti-inflammation-related microbes and metabolites.

Impact of epizootics on mussel farms: Insights into microbiota composition of Mytilus species

Outbreaks of marine mussel mortality on French farms could have different aetiologies. One of them implies Vibrio splendidus strains. Beyond the involvement of this pathogen, there is considerable evidence that diseases often result from interactions between several microbes and the host. In this study, we explored the bacterial communities associated with mussel species and the surrounding water collected from a mussel farm affected by mortalities. The microbiota of Mytilus edulis, Mytilus galloprovincialis and their hybrids displayed an abnormal abundance of Proteobacteria, in particular the genera Vibrio, Cobetia and Arcobacter. Despite the dysbiosis, the Mediterranean mussel showed a different microbiota profile with a higher richness and presence of the phylum Bacteroidetes. Bipartite network analyses at the level of bacteria families confirmed this finding and showed that the microbiomes of M. edulis and the hybrids tended to cluster together. In addition, injection of mussels with the virulent V. splendidus induced less mortality rate in M. galloprovincialis compared to the other Mytilus sp. suggesting a better resistance of the Mediterranean mussel to infection. Our findings point to a probable aetiology of pathobiome-mediated disease in mussels. To fully understand this phenomenon, more knowledge is needed on the roles of pathobiotic systems and their development during disease establishment.

Genetically predicted gut microbiome and risk of oral cancer

PURPOSE

Mounting evidence suggests a possible link between gut microbiome and oral cancer, pointing to some potential modifiable targets for disease prevention. In the present study, Mendelian randomization (MR) was used to explore whether there was a causal link between gut microbiome and oral cancer.

METHODS

The single nucleotide polymorphisms (SNPs) significantly associated with gut microbiome were served as instrumental variables. MR analyses were performed using genetic approaches such as inverse variance weighting (IVW), MR Egger and weighted median, with IVW as the primary approach, supplemented by MR Egger and weighted median. Mendelian randomization pleiotropy residual sum and outlier (MR-PRESSO) and MR-Egger regression were used to detect the presence of horizontal pleiotropy and identify outlier SNPs.

RESULTS

Causal effect estimates indicated that genetically predicted abundance of Prevotellaceae was associated with higher risk of oral cancer (odds ratio (OR) 1.80, 95% confidence interval (CI) 1.16-2.81, p = 0.009). There was no evidence of notable heterogeneity and horizontal pleiotropy.

CONCLUSION

Genetically derived estimates suggest that Prevotellaceae may be associated with the risk of oral cancer. Such robust evidence should be given priority in future studies and explore the underlying mechanisms.

The role of vitamin D in depression and anxiety disorders: a review of the literature

BACKGROUND

Prevalence of mental health disorders continue to increase worldwide. Over the past decades, suboptimal vitamin D (VD) levels and gut dysbiosis have been associated with neurological dysfunction and psychiatric disorders.

METHODS

In this review, we examined the available literature on VD and mental health disorders, particularly depression and anxiety, in both clinical and pre-clinical studies.

RESULTS

Our extensive review failed to find a link between VD deficiency, depression, and anxiety-related behavior in preclinical animal models. However, strong evidence suggests that VD supplementation may alleviate symptoms in chronically stressed rodents, with some promising evidence from clinical studies. Further, fecal microbiota transplantations suggest a potential role of gut microbiota in neuropsychiatric disorders, although the underlying mechanisms remain to be fully elucidated. It has been postulated that serotonin, primarily produced by gut bacteria, may be a crucial factor. Hence, whether VD has the ability to impact gut microbiota and modulate serotonin synthesis warrants further investigation.

CONCLUSIONS

Taken together, literature has suggested that VD may serve as a key regulator in the gut-brain axis to modulate gut microbiota and alleviate symptoms of depression and anxiety. The inconsistent results of VD supplementation in clinical studies, particularly among VD deficient participants, suggests that current intake recommendations may need to be re-evaluated for individuals at-risk (i.e. prior to diagnosis) of developing depression and/or anxiety.

Gut microbiome as a treatment in colorectal cancer

BACKGROUND

The gut microbiome plays a role in the development and progression of colorectal cancer (CRC).

AIM AND OBJECTIVE

This review focuses on whether the gut microbiome is involved in the development and regulation of the host immune system.

METHODS

The gut microbiome can influence the production and activity of immune cells and molecules that help to maintain the integrity of the intestinal barrier and prevent inflammation. Gut microbiota modulates the anti-cancer immune response. The gut microbiota can influence the function of immune cells, like T cells, that recognize and eliminate cancer cells. Gut microbiota can affect various aspects of cancer progression and the efficacy of various anti-cancer treatments.

RESULTS

Gut microbiota provide promise as a potential biomarker to identify the effect of immunotherapy and as a target for modulation to improve the efficacy of immunotherapy in CRC treatment.

CONCLUSION

The potential synergistic effect between the gut microbiome and anti-cancer treatment modalities provides an interest in developing strategies to modulate the gut microbiome to improve the efficacy of anti-cancer treatment.