Role of the Gut Microbiota and Its Metabolites in Tumorigenesis or Development of Colorectal Cancer

Role of gut microbiome in suppression of cancers

The pathogenesis of cancer is closely related to the disruption of homeostasis in the human body. The gut microbiome plays crucial roles in maintaining the homeostasis of its host throughout lifespan. In recent years, a large number of studies have shown that dysbiosis of the gut microbiome is involved in the entire process of cancer initiation, development, and prognosis by influencing the host immune system and metabolism. Some specific intestinal bacteria promote the occurrence and development of cancers under certain conditions. Conversely, some other specific intestinal bacteria suppress the oncogenesis and progression of cancers, including inhibiting the occurrence of cancers, delaying the progression of cancers and boosting the therapeutic effect on cancers. The promoting effects of the gut microbiome on cancers have been comprehensively discussed in the previous review. This article will review the latest advances in the roles and mechanisms of gut microbiome in cancer suppression, providing a new perspective for developing strategies of cancer prevention and treatment.

Indole-3-lactic acid suppresses colorectal cancer via metabolic reprogramming

Research indicates that abnormal gut microbiota metabolism is linked to colorectal cancer (CRC) progression, but the role of microbiota-related tryptophan metabolism disruption remains unclear. Using metagenomic sequencing and targeted Trp metabolomics, our research identified that CRC patients had abnormal indole-3-lactic acid (ILA) levels, which were related to tumor malignancy. Exogenous ILA administration suppressed CRC development in AOM/DSS induced and xenograft mice models. Furthermore, in vitro experiments demonstrated that ILA inhibits tumor cell proliferation, migration, and anti-apoptotic capabilities. Mechanistically, ILA appears to directly occupy the phosphorylation sites of STAT3, leading to a reduction in intracellular phosphorylated STAT3 (p-STAT3) levels and the inhibition of the HK2 pathway, thereby downregulating glucose metabolism in cancer cells. Notably, this inhibition is independent of the aryl hydrocarbon receptor (AHR). In conclusion, our research findings demonstrate that alterations in tryptophan metabolism among CRC patients can influence tumor progression and reveal a novel mechanism through which ILA exerts its inhibitory effects on CRC. These findings offer new insights into the role of gut microbiota in CRC and identify potential clinical therapeutic targets.

Desulfovibrio vulgaris flagellin exacerbates colorectal cancer through activating LRRC19/TRAF6/TAK1 pathway

The initiation and progression of colorectal cancer (CRC) are intimately associated with genetic, environmental and biological factors. Desulfovibrio vulgaris (DSV), a sulfate-reducing bacterium, has been found excessive growth in CRC patients, suggesting a potential role in carcinogenesis. However, the precise mechanisms underlying this association remain incompletely understood. We have found Desulfovibrio was abundant in high-fat diet-induced Apcmin/+ mice, and DSV, a member of Desulfovibrio, triggered colonocyte proliferation of germ-free mice. Furthermore, the level of DSV progressively rose from healthy individuals to CRC patients. Flagella are important accessory structures of bacteria, which can help them colonize and enhance their invasive ability. We found that D. vulgaris flagellin (DVF) drove the proliferation, migration, and invasion of CRC cells and fostered the growth of CRC xenografts. DVF enriched the epithelial-mesenchymal transition (EMT)-associated genes and characterized the facilitation of DVF on EMT. Mechanistically, DVF induced EMT through a functional transmembrane receptor called leucine-rich repeat containing 19 (LRRC19). DVF interacted with LRRC19 to modulate the ubiquitination of tumor necrosis factor receptor-associated factor (TRAF)6, rather than TRAF2. This interaction drove the ubiquitination of pivotal molecule TAK1, further enhancing its autophosphorylation and ultimately contributing to EMT. Collectively, DVF interacts with LRRC19 to activate the TRAF6/TAK1 signaling pathway, thereby promoting the EMT of CRC. These data shed new light on the role of gut microbiota in CRC and establish a potential clinical therapeutic target.

Sophocarpine suppresses MAPK-mediated inflammation by restoring gut microbiota in colorectal cancer

BACKGROUND

Colorectal cancer (CRC), as one of the most common cancers globally, poses a significant challenge to public health due to its high incidence and mortality rates. This underscores the need for continuous exploration of new therapeutic targets and effective drugs. Sophocarpine (SC), a natural compound derived from traditional Chinese medicine, holds considerable therapeutic potential in the treatment of CRC, however, the relevant mechanisms remains unclear.

PURPOSE

This study aims to explore the anti-tumor effects of SC against CRC by modulating gut microbiota, and uncover potential mechanisms linking SC's therapeutic effects to gut microbiota regulation by analyzing the impact of SC on microbiota composition and CRC progression.

MATERIAL

This study explores the impact of SC on the gut microbiota in CRC by constructing subcutaneous xenograft tumors of CRC and integrating 16S rRNA sequencing and RNA transcriptomic sequencing. The fecal microbiota transplantation (FMT) mouse model was used to validate the biological function of SC in correcting gut microbiota dysbiosis to treat CRC. Subsequently, we conducted in vitro studies on the molecular mechanisms by which SC regulates the gut microbiota as an effective hallmark of CRC treatment, using lipopolysaccharide (LPS) to simulate an inflammatory gut microbiota environment and P38 MAPK knockdown cell line.

RESULTS

SC significantly inhibited CRC cell proliferation with IC50 values of 2.547±0.256 μM for HCT116 and 2.851±0.332 μM for LoVo cells. In vivo experiments demonstrated that SC effectively suppressed tumor growth in xenograft models. 16S rRNA sequencing revealed that SC modulated gut microbiota composition, particularly affecting Bacteroides and Alistipes populations. SC significantly reduced the levels of inflammatory factors and inhibited the MAPK signaling pathway, as evidenced by decreased p-JNK, p-p38 MAPK, and p-NF-κB p65 expression.

CONCLUSIONS

Current clinical practice still lacks effective therapeutic agents targeting CRC through gut microbiota modulation. This study presents the first evidence that SC, a natural compound, exhibits dual-action therapeutic efficacy against CRC progression by simultaneously modulating gut microbial composition and suppressing MAPK pathway-mediated inflammatory responses. These findings highlight SC's novel therapeutic potential as a promising microbiota-regulating candidate for CRC intervention, offering an innovative approach that bridges microbial ecology with cancer signaling pathways.

Cross-cohort analysis identifies shared gut microbial signatures and validates microbial risk scores for colorectal cancer

BACKGROUND

Microbiome-wide association studies showed links between colorectal cancer (CRC) and gut microbiota. However, the clinical application of gut microbiota in CRC prevention has been hindered by the diversity of study populations and technical variations. We aimed to determine CRC-related gut microbial signatures based on cross-regional, cross-population, and cross-cohort metagenomic datasets, and elucidate its application value in CRC risk assessment.

METHODS

We used the MMUPHin tool to perform a meta-analysis of our own cohort and seven publicly available metagenomics datasets to identify gut microbial species associated with CRC across different cohorts, comprising of 570 CRC cases and 557 controls. Based on differential species sets, we constructed the microbial risk score (MRS) using α-diversity of the sub-community (MRSα), weighted/unweighted summation methods and machine learning algorithms. Cohort-to-cohort training and validation were performed to demonstrate the transferability.

RESULTS

We found that MRSα of core species was better validated and more interpretable than those constructed with summation methods or machine learning algorithms. Six species, including Parvimonas micra, Clostridium symbiosum, Peptostreptococcus stomatis, Bacteroides fragilis, Gemella morbillorum, and Fusobacterium nucleatum, were included in MRSα constructed by half or more of the cohorts. The AUC of MRSα, calculated based on the sub-community of six species, varied between 0.619 and 0.824 across the eight cohorts.

CONCLUSION

We identified six CRC-related species across regions, populations, and cohorts. The constructed MRSα could contribute to the risk prediction of CRC in different populations.

Butyrate confers colorectal cancer cell resistance to anti-PD-1 therapy by promoting CPT1A-mediated fatty acid oxidation

Immunotherapy including anti-PD-1 demonstrated therapeutic promise to colorectal cancer (CRC) patients, but tumor cell resistance limits their efficacy. Butyrate may influence therapeutic outcomes by modulating tumor metabolism, but it remains unclear whether butyrate influences CRC cell resistance to anti-PD-1 therapy. We aimed to investigate whether butyrate promotes resistance to anti-PD-1 therapy in CRC and underlying metabolic and immunologic mechanisms. CRC murine models were established by subcutaneously inoculating MC38 cells or butyrate/anti-PD-1-administered tumor cells of mice, followed by treatment with butyrate, anti-PD-1, or a combination. Therapeutic efficacy was assessed by tumor growth and survival outcomes. In vitro, HCT116 cells were exposed to monotherapy or co-therapy regimens. Carnitine Palmitoyltransferase 1A (CPT1A) knockdown was conducted by shRNA transfection both in vivo and in vitro. Fatty acid oxidation (FAO) was determined by oxygen consumption rate and CPT1A expression. CD8+ T cell cytotoxicity assays and CD8 expression in tumors were performed to evaluate immune cell infiltration. The addition of butyrate into anti-PD-1 treatment combination did not improve survival or reduce tumor volume compared to anti-PD-1 alone, with a marked activation of CPT1A observed in treated tumor tissues. Butyrate significantly elevated FAO, contributing to elevated oxygen consumption rate and reduced CD8+ T cell cytotoxicity. However, in sh-CPT1A models, the combination therapy significantly improved antitumor efficacy and restored CD8+ T cell infiltration. Furthermore, CRC patient samples resistant to anti-PD-1 therapy exhibited elevated CPT1A levels. Butyrate-induced CPT1A-mediated FAO promotes resistance to anti-PD-1 therapy in CRC, suggesting that targeting CPT1A might enhance the efficacy of immunotherapy.

Temporal network analysis of gut microbiota unveils aging trajectories associated with colon cancer

The human gut microbiome's role in colorectal cancer (CRC) pathogenesis has gained increasing recognition. This study aimed to delineate the microbiome characteristics that distinguish CRC patients from healthy individuals, while also evaluating the influence of aging, through a comprehensive metagenomic approach. The study analyzed a cohort of 80 CRC patients and 80 matched healthy controls, dividing participants into a normal and a CRC group, further categorized by age into young, middle-aged, and old-aged subgroups. Extensive metagenomic sequencing of fecal samples allowed for the exploration of both the structural and functional profiles of the microbiome, with findings validated in an independent cohort to ensure robustness. Our results highlight notable differences in microbiome composition between CRC patients and healthy individuals, which exhibit age-dependent variations. Specifically, a higher prevalence of pathogenic bacteria, such as Bacteroides vulgatus, known to drive inflammation and carcinogenesis, was observed in CRC patients, alongside a reduction in beneficial microbes, including Lactobacillus. Functionally, the CRC-associated microbiome showed an increase in pathways related to DNA repair, cell cycle regulation, and metabolic activities, such as the Citrate cycle and Galactose metabolism, underscoring distinct microbial alterations in CRC patients that could influence disease onset and progression. These insights lay a foundation for future research into microbiome-based diagnostics and treatments for CRC.

IMPORTANCE

This study underscores the critical role of the gut microbiome in colorectal cancer (CRC) pathogenesis, particularly in the context of aging. By identifying age-specific microbial biomarkers and functional pathways associated with CRC, our findings provide novel insights into how microbiome composition and metabolic activities influence disease progression. These discoveries pave the way for developing personalized microbiome-based diagnostic tools and therapeutic strategies, potentially improving CRC prevention and treatment outcomes across different age groups. Understanding these microbial dynamics could also inform interventions targeting gut microbiota to mitigate CRC risk and progression.

Links between short-chain fatty acids and osteoarthritis from pathology to clinic via gut-joint axis

Short-chain fatty acids (SCFAs), the primary metabolites produced by the microbial fermentation of dietary fibers in the gut, have a key role in protecting gut health. Increasing evidence indicates SCFAs can exert effects on distant tissues and organs beyond the gut via blood circulation. Osteoarthritis (OA) is a chronic inflammatory joint disease that severely diminishes the physical function and quality of life. However, effective clinical treatments for OA remain elusive. Recent studies have shown that SCFAs can exert beneficial effects on damaged joints in OA. SCFAs can mitigate OA progression by preserving intestinal barrier function and maintaining the integrity of cartilage and subchondral bone, suggesting that they have substantial potential to be the adjunctive treatment strategy for OA. This review described the SCFAs in the human body and their cellular signaling mechanism, and summarized the multiple effects of SCFAs (especially butyrate, propionate, and acetate) on the prevention and treatment of OA by regulating the gut-joint axis, providing novel insights into their promising clinical applications.

Gut microbiota influences colorectal cancer through immune cell interactions: a Mendelian randomization study

BACKGROUND

Colorectal cancer (CRC) is the most prevalent malignant tumor of the digestive system globally, posing a significant threat to human health and quality of life. Recent studies have established associations between gut microbiota and immune cells with CRC; however, the mechanisms by which gut microbiota influence the development and progression of CRC through immune mediators remain poorly understood.

METHODS

We conducted a two-sample, bidirectional Mendelian randomization analysis. We utilized 731 immune cell types and 473 gut microbial species along with colorectal cancer statistics from published summary statistics from genome-wide association studies (GWAS).The analysis employed several methodologies, including inverse variance-weighted (IVW) analysis, MR-Egger regression, the weighted median method, and both weighted and simple model approaches.Sensitivity analyses were performed to confirm the reliability of the Mendelian randomization results, and reverse Mendelian randomization was used to assess the overall impact of CRC on gut microbiota and immune cells.

RESULTS

Our findings suggest a causal relationship involving nine immunophenotypes and five specific gut microbial taxa with CRC. Notably, the gut microbes Alloprevotella and Holdemania, along with immune cell types CD3 on CD28- CD8br and CD4 + T cells, demonstrated significant causal associations with CRC. Mediation analysis revealed that the association between Alloprevotella and CRC was mediated by CD4 + T cells, with a mediation effect of 6.48%. Additionally, Holdemania was found to mediate its association with CRC through CD3 on CD28- CD8br, exhibiting a mediation effect of 9.29%. Reverse Mendelian randomization did not indicate any causal effect of CRC on specific immune cells or gut microbiota. Two-sided sensitivity analyses revealed no evidence of heterogeneity or horizontal pleiotropy in our findings.

CONCLUSIONS

This comprehensive Mendelian randomization study enhances our understanding of the mechanisms by which gut microbiota affects CRC through immune cell interactions. Further investigations are warranted to unravel the underlying mechanisms linking gut microbiota, immune cells, and colorectal cancer.

Interplay between the gut microbiota, its metabolites and carcinogens

The gut microbiota is a complex and dynamic community of microorganisms that reside in the gastrointestinal tract, playing a critical role in the host. It produces many metabolites, such as bile acids, which play an important role in the metabolism of the host. One area of particular interest is its involvement in the development and treatment of cancer. Carcinogens, which are substances known to promote cancer formation and development, are present in various sources in our daily lives, including cigarettes, barbecues, and moldy foods. The types, amounts, and metabolism of carcinogens have been closely linked to cancer risk, underscoring the importance of understanding their interplay with the gut microbiota. Numerous studies have demonstrated significant differences in the composition and function of the gut microbiota in individuals with cancer compared to healthy individuals. The gut microbiota and its metabolites have been shown to influence the metabolism of various carcinogens, thereby affecting cancer progression. While much attention has been paid to the relationship between the gut microbiota and cancer risk, the potential interplay between the gut microbiota and carcinogens has received less focus. This review aims to emphasize the importance of exploring the interplay between the gut microbiota with its metabolites and carcinogens in cancer development and therapy. By uncovering the mechanisms of the interplay, new approaches for cancer prevention and treatment can be developed.

Causal effect of gut microbiota metabolic pathways on CSAG1 expression in chondrosarcoma: a mendelian randomization analysis

BACKGROUND

Changes in gut microbiota metabolism might play an important role in the development of some cancers. However, the causal relationships of gut microbiome-related metabolic pathways in chondrosarcomas and the specific pathways affected remain largely unknown.

METHODS

We used two-sample bidirectional and multivariate Mendelian randomization (MR) to reveal a causal relationship between the gut microbiota metabolic pathway (GMMP) and chondrosarcoma associated gene 1(CSAG1) via the largest available genome-wide association study (GWAS).

RESULTS

Univariate MR analysis revealed that tetrapyrrole biosynthesis from glutamate, menaquinol 6 biosynthesis, glycogen degradation II, 8-amino-7-oxononanoate biosynthesis, taxadiene biosynthesis, glycolysis and tRNA charging had a significant causal relationship with CSAG1.Multivariate MR analysis suggested that tetrapyrrole biosynthesis, menaquinol 6 biosynthesis, glycogen degradation II, glycolysis and tRNA charging still had a significant causal effect on CSAG1. According to the results of reverse MR analysis, no significant causal effect of CSAG1 on the GMMP was found.

CONCLUSIONS

This study offers further insights into the gut microbiota-mediated mechanism of chondrosarcoma development.

Stroke-Associated Pneumonia and the Brain-Gut-Lung Axis: A Systematic Literature Review

BACKGROUND

Stroke-associated pneumonia (SAP), a highly lethal complication following stroke, is closely linked to dysregulation of the "brain-gut-lung axis." Accumulating evidence indicates that stroke triggers intestinal alterations through the brain-gut axis, while multiple studies confirm that gut-derived changes can mediate pneumonia through the gut-lung axis. However, the mechanisms connecting stroke-induced intestinal dyshomeostasis to SAP remain incompletely elucidated, and the multiorgan interaction mechanisms of the "brain-gut-lung axis" in SAP pathogenesis require further exploration.

REVIEW SUMMARY

This systematic literature review systematically searched databases, including PubMed, using the keywords "stroke," "gastrointestinal microbiome," and "bacterial pneumonia," incorporating 80 mechanistic studies. Key findings reveal that stroke initiates a cascade of "neuro-microbial-immune" pathway interactions along the brain-gut-lung axis, leading to intestinal dyshomeostasis characterized by microbiota and metabolite alterations, barrier disruption, immune dysregulation, inflammatory responses, and impaired gut motility. These intestinal perturbations ultimately disrupt pulmonary immune homeostasis, promoting SAP development. In addition, stroke directly induces vagus nerve injury through the brain-gut axis, resulting in impaired swallowing and cough reflexes that exacerbate aspiration-related pulmonary infection risks.

CONCLUSIONS

Elucidating the role of the brain-gut-lung axis in SAP pathogenesis provides critical insights into its underlying mechanisms. This paradigm highlights intestinal homeostasis modulation and vagus nerve stimulation as promising therapeutic strategies for SAP prevention and management, advancing a multitargeted approach to mitigate poststroke complications.

The gastrointestinal mycobiome in inflammation and cancer: unraveling fungal dysbiosis, pathogenesis, and therapeutic potential

The gastrointestinal mycobiome, comprising diverse fungal species, plays a significant role in gastrointestinal carcinogenesis and inflammatory bowel disease (IBD) pathogenesis. Recent studies have demonstrated that dysbiosis of the gut mycobiome, characterized by an overrepresentation of pathogenic fungi such as Candida albicans and Aspergillus, correlates with increased inflammation and cancer risk. For instance, C. albicans has been shown to induce colonic inflammation through the activation of pattern recognition receptors and the release of pro-inflammatory cytokines, exacerbating IBD symptoms and potentially facilitating tumorigenesis. Additionally, metagenomic analyses have revealed distinct fungal signatures in colorectal cancer tissues compared to adjacent healthy tissues, highlighting the potential of fungi as biomarkers for disease progression. Mechanistically, gut fungi contribute to disease through biofilm formation, mycotoxin secretion (e.g., aflatoxins, candidalysin), pro-inflammatory cytokine induction (e.g., IL-1β, IL-17), and disruption of epithelial barriers-creating a tumor-promoting and inflammation-prone environment. Furthermore, the interplay between fungi and the bacterial microbiome can amplify inflammatory responses, contributing to chronic inflammation and cancer development. Fungal interactions with bacterial communities also play a synergistic role in shaping mucosal immune responses and enhancing disease severity in both cancer and IBD contexts. As research continues to elucidate these complex fungal-host and fungal-bacterial interactions, targeting the gut mycobiome may offer novel therapeutic avenues for managing IBD and gastrointestinal cancers, emphasizing the need for integrated, mechanistically informed approaches to microbiome research.

CiLi (Rosa roxburghii Tratt.) polyphenols improve colitis via gut microbiota-lipid mediator-immunity axis

Dysbiosis of gut microbiome is one of the most important factors leading to inflammatory bowel disease (IBD). Intake of phytochemicals from fruits and vegetables is an effective way to improve IBD, but how these bioactivators regulate gut microbiota to exert healthy effects remains unclear. Here, we found that pretreatment with CiLi juice, particularly its polyphenol component, alleviated dextran sulfate sodium (DSS)-induced colitis while preserving intestinal barrier integrity. CiLi polyphenols (CL_PP) reduced inflammation and oxidative stress in colon tissue and enriched fecal short-chain fatty acids. Importantly, CL_PP significantly regulated the gut microbiome diversity, increasing beneficial bacteria (e.g., Clostridia_UCG-014, f_Muribaculaceae and Ileibacterium_valens) while decreasing harmful bacteria (Escherichia-Shigella and Romboutsia). Multiomics analysis revealed that CL_PP upregulated bioactive lipid metabolites, particularly those derived from polyunsaturated fatty acids (e.g., resolvin D2, prostaglandin A1, and glycerophosphocholine) related gene expressions (Pltp, Alox15 and Pld4). Additionally, CL-PP downregulated the oxidative stress markers (oxidized glutathione and glutathione peroxidase 3), and immune cell markers (CD8 and CD68). Fecal microbiota transplantation confirmed that the fecal microbiota from CL_PP-treated mice exhibited anti-colitis effects. These effects were diminished in antibiotic-treated mice, underscoring the importance of the gut microbiota in mediating the CL_PP's anti-inflammatory benefits. This study suggests that CL_PP is a potential modulator of gut microbiome dysbiosis for the prevention and treatment of colitis.

A Sequential Release Micro-nano System for Colitis Therapy via Gut Microbiota and Immune Regulation

Commencing with the breakdown of the intestinal barrier, various pathogenic factors, such as dysbiosis of the gut microbiota, harmful inflammatory cytokines, and immune system imbalance, collectively contribute to the development of colitis. Numerous interventions focusing on single factors have been developed to provide short-term therapeutic benefits, but the continued existence of unresolved pathogenic factors can lead to disease exacerbation. Here we have designed a multicomponent system-inulin microspheres encapsulating selenium-containing nanomicelles, aiming to tackle the multiple factors associated with colitis. This micro-nano drug delivery platform achieves sequential release of drugs in the inflamed colon, with each component of the system functioning independently and jointly. The outer layer of inulin supplies nutrients for probiotics. The inner core comprises selenocystamine and 3-oxolithocholic acid, which polarize macrophages towards an anti-inflammatory phenotype and regulate adaptive immunity by inhibiting TH17-cell differentiation, respectively. In an acute colitis mouse model, this therapeutic system ameliorates colonic inflammation, enhances the abundance of gut microbiota, and modulates the mucosal immune system, showing potential in preventing colitis.

Intratumoral microbiota predicts the response to neoadjuvant chemoimmunotherapy in triple-negative breast cancer

BACKGROUND

Neoadjuvant immunotherapy combined with chemotherapy (Chemo-IM) is associated with significantly improved pathological complete response (pCR) rates and long-term survival outcomes in patient with early-stage triple-negative breast cancer (TNBC). However, only a small proportion of patients benefit from the addition of immunotherapy. Here, we explored and confirmed the role of intratumoral microbiota in screening patients with TNBC who are likely to benefit from neoadjuvant Chemo-IM.

METHODS

Patients with previously untreated, non-metastatic TNBC receiving neoadjuvant Chemo-IM were enrolled. Differences in the intratumoral microbiota between the pCR and non-pCR groups were explored via 16S rDNA sequencing (16S-seq). Single-cell transcriptome sequencing (scRNA-seq) was employed to profile the tumor microenvironment (TME). Moreover, correlations between the intratumor microbiota and the TME were explored. Finally, machine-learning models based on the intratumoral microbiota were constructed to predict pCR.

RESULTS

A total of 89 female patients with early-stage TNBC treated by neoadjuvant Chemo-IM were enrolled. We found that the pCR group had greater diversity and a higher load of intratumoral microbiota than the non-pCR group. Intriguingly, scRNA-seq revealed significantly increased T cell infiltration and decreased tumor-associated macrophage infiltration into tumors in the pCR group. Moreover, intratumoral microbiota load was positively associated with CD4+CXCL13+ T cell infiltration and negatively associated with CD68+SPP1+ macrophage infiltration. Combined analysis of 16S-seq and scRNA-seq data revealed that intratumoral microbiota were present in both cancer and immune cells. Finally, we developed a model incorporating intratumoral microbiota and clinicopathological characteristics, and it showed strong power for predicting pCR to neoadjuvant Chemo-IM.

CONCLUSIONS

Intratumoral microbiota may serve as a strong and specific predictor of the response of patients with early-stage TNBC to neoadjuvant Chemo-IM. Our findings could contribute to the development of individualized Chemo-IM strategies for treating TNBC.

Naringenin Inhibits Colorectal Cancer associated with a High-Fat Diet through Modulation of Gut Microbiota and IL-6/STAT3 Pathway

Colorectal cancer (CRC) is a worldwide health issue. It causes illness and death in millions of people each year. A positive correlation has been observed between the intake of dietary fat and the development of CRC. The composition of gut microbiota exhibits a significant correlation with pathophysiologic processes in intestine. Clinical treatment remains inadequate due to the complex pathogenic mechanisms of CRC triggered by a high-fat diet (HFD). Naringenin, a flavonoid from grapefruit, has anti-cancer activity. Our findings suggest that naringenin enhances gut microbiota diversity by increasing the abundance of beneficial bacterial species while reducing opportunistic pathogenic bacteria. The fecal microbiota transplantation assay (FMT) demonstrated that the anti-HFD-CRC activity of naringenin depended on the gut microbiota. Furthermore, naringenin antagonized the IL-6/STAT3 pathway. These results suggest that naringenin may be a potential treatment for HFD-CRC.

Metagenomic Microbial Signatures for Noninvasive Detection of Pancreatic Cancer

Background/Objectives: Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive malignancy with poor early detection rates owing to the limited sensitivity and specificity of the current biomarker CA19-9. Gut microbiota dysbiosis plays a key role in PDAC pathogenesis. This study aimed to evaluate the noninvasive approach we developed, combining metagenome-derived microbial signatures with CA19-9, to improve PDAC detection. Methods: This study included 50 treatment-naïve patients with PDAC and their matched controls. Fecal samples were analyzed using shotgun metagenomic sequencing. Machine learning algorithms were used to develop and validate a diagnostic panel integrating microbial signatures and CA19-9 levels. Subgroup analyses were used to confirm the robustness of the microbial markers. Results: The combined models at both species and genus levels effectively distinguished patients with PDAC from healthy individuals, and their strong diagnostic efficacy and accuracy were demonstrated through rigorous validation. Conclusions: In conclusion, the combination of gut microbiome profiling and CA19-9 improves PDAC detection accuracy compared to the use of CA19-9 alone, showing promise for early and noninvasive diagnosis.

Novel insights into immune-gut microbiota interactions in colorectal cancer: a Mendelian randomization study

BACKGROUND

The relationship between immune cells and colorectal cancer (CRC) development has been extensively studied; however, the mediating role of gut microbiota in this relationship remains poorly understood.

METHODS

We utilized summary data from genome-wide association studies (GWAS) to analyze 731 immune cell phenotypes, 473 gut microbiota, and CRC-related data. A two-step mediation analysis was employed to identify mediating gut microbiota. The primary analysis method was inverse variance weighting (IVW), supplemented by MR-Egger, simple mode, weighted median, and weighted mode analyses. Robustness of the results was ensured through systematic sensitivity analyses.

RESULTS

Our analysis identified 13 immune cell phenotypes significantly associated with CRC, including 10 protective factors and 3 risk factors. Additionally, 13 gut microbiota showed significant associations with CRC, comprising 8 protective factors and 5 risk factors. Mediation analysis revealed that 4-gut microbiota (1 order, 1 family, 1 genus, and 1 unclassified) mediated the relationship between immune cells and CRC. For instance, unclassified CAG - 977 mediated the effects of FSC-A on NK and NKT %lymphocyte on CRC risk, with mediation proportions of 11% and 12.3%, respectively. Notably, 22.3% of the protective effect of EM CD8br %CD8br on CRC was mediated through order Francisellales.

CONCLUSION

This study provides evidence for a potential causal relationship between immune cells, gut microbiota, and CRC, highlighting the mediating role of specific gut microbiota. These findings offer new insights into the pathogenesis of CRC and may inform future therapeutic strategies.

Gut microbiota affects PD-L1 therapy and its mechanism in melanoma

Immune checkpoint inhibitors (ICIs), particularly PD-1/PD-L1 blockade, have shown great success in treating melanoma. PD-L1 (B7-H1, CD274), a ligand of PD-1, binds to PD-1 on T cells, inhibiting their activation and proliferation through multiple pathways, thus dampening tumor-reactive T cell activity. Studies have linked PD-L1 expression in melanoma with tumor growth, invasion, and metastasis, making the PD-1/PD-L1 pathway a critical target in melanoma therapy. However, immune-related adverse events are common, reducing the effectiveness of anti-PD-L1 treatments. Recent evidence suggests that the gut microbiome significantly influences anti-tumor immunity, with the microbiome potentially reprogramming the tumor microenvironment and overcoming resistance to anti-PD-1 therapies in melanoma patients. This review explores the mechanisms of PD-1/PD-L1 in melanoma and examines how gut microbiota and its metabolites may help address resistance to anti-PD-1 therapy, offering new insights for improving melanoma treatment strategies.

Gut microbiome signature in response to neoadjuvant chemoradiotherapy in patients with rectal cancer

Background

Rectal cancer remains a leading cause of cancer-associated mortality, especially in advanced cases with limited treatment options. Emerging evidence suggests that the gut microbiome may influence the therapeutic efficacy of neoadjuvant chemoradiotherapy (CRT).

Objective

This study aimed to explore the dynamic changes in gut microbiome composition and metabolic pathways in rectal cancer patients undergoing CRT.

Methods

Paired fecal samples were collected from rectal cancer patients pre- and post-CRT. 16S rRNA amplicon sequencing and proteomics analysis were conducted to investigate microbial and metabolic alterations.

Results

Significant shifts in the microbiome were observed, with Fusobacterium, Subdoligranulum, Prevotella, Alloprevotella, and Bacteroides being enriched pre-CRT, while Streptococcus, Megamonas, Megasphaera, Escherichia-Shigella, and Olsenella became dominant post-CRT. Metabolic analysis revealed upregulated carbohydrate metabolism and downregulated lipid and energy metabolism.

Conclusion

These findings identify potential microbial biomarkers and metabolic pathways associated with CRT response, offering insights into personalized treatment strategies.

Burn-Induced Gut Microbiota Dysbiosis Aggravates Skeletal Muscle Atrophy by Tryptophan-Kynurenine Mediated AHR Pathway Activation

The hypermetabolic response associated with burns is characterized by skeletal muscle atrophy and an increased incidence of disability and death. Significant remodeling of the gut microbiota occurs after severe burn trauma. However, the specific mechanisms by which gut microbiota contribute to burn-induced muscle atrophy remain unexplored. The results showed that the disruption of the gut microbiota exacerbated skeletal muscle atrophy. Fecal metabolite analysis revealed perturbations, primarily within the tryptophan (Trp) metabolic pathway. Animal models further demonstrated that gut microbiota disorder enhanced the expression of indoleamine 2,3-dioxygenase 1 (IDO-1) in the colon, ultimately resulting in Trp depletion and increased kynurenine (Kyn) levels in the serum and skeletal muscle. Excessive colonic Kyn is released into circulation, transported into skeletal muscle cells, and binds to the aryl hydrocarbon receptor (AHR), consequently triggering AHR nuclear translocation and initiating the transcription of skeletal muscle atrophy-related genes. Notably, serum samples from patients with burns exhibited Trp depletion, and Trp supplementation alleviated skeletal muscle atrophy in rats with burns. This study, for the first time, demonstrates that gut microbiota dysbiosis upregulates colonic IDO-1, promotes Trp-Kyn metabolism, and exacerbates burn-induced skeletal muscle atrophy, suggesting that Trp supplementation may be a potential therapeutic strategy.

Structural and functional alteration of the gut microbiomes in ICU staff: a cross-sectional analysis

BACKGROUND

16S rRNA sequencing has revealed structural alterations in the gut microbiomes of medical workers, particularly those working in intensive care unit (ICU). This study aims to further compare the taxonomic and functional characteristics of gut microbiomes between ICU staff and non-medical individuals using metagenomic sequencing.

METHODS

A prospective cross-sectional cohort study was conducted, fecal samples from 39 individuals in each group-ICU staff and non-medical subjects were analyzed using metagenomic sequencing. PERMANOVA (using the adonis function) was employed to analyze the genus-level profiles and assess the impact of individual parameters on the gut microbiome. Multiple databases were utilized to annotate and compare the functional differences in gut microbiomes between the two groups.

RESULTS

We observed that ICU staff exhibited a significant decrease in gut microbiome diversity, characterized by a marked decline in Actinobacteria and a substantial increase in Bacteroides and Bacteroidaceae. CAZy annotation revealed a notable increase in carbohydrate-active enzymes within the ICU staff cohort. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis further indicated an elevated risk of endocrine and metabolic disorders, along with enhanced glycan biosynthesis and metabolism. Additionally, KEGG pathway enrichment analysis highlighted significant enrichment in cancer-related pathways. Analysis using the Virulence Factor Database (VFDB) showed a higher abundance of virulence factors associated with immune modulation, invasion, and antimicrobial activity/competitive advantage among ICU staff. Notably, no discernible difference in the presence of antibiotic resistance genes within the gut microbiomes was observed between the two groups. Importantly, all aforementioned differences demonstrated clear gender disparities.

CONCLUSIONS

Our findings indicated that ICU staff exhibited a reduction in gut microbiome diversity which was associated with an increase in virulence factors and carbohydrate-active enzymes, as well as with a heightened susceptibility to endocrine and metabolic diseases and cancers.

Exploring the role of gut microbiota in colorectal liver metastasis through the gut-liver axis

Colorectal liver metastasis (CRLM) represents a major therapeutic challenge in colorectal cancer (CRC), with complex interactions between the gut microbiota and the liver tumor microenvironment (TME) playing a crucial role in disease progression via the gut-liver axis. The gut barrier serves as a gatekeeper, regulating microbial translocation, which influences liver colonization and metastasis. Through the gut-liver axis, the microbiota actively shapes the TME, where specific microbial species and their metabolites exert dual roles in immune modulation. The immunologically "cold" nature of the liver, combined with the influence of the gut microbiota on liver immunity, complicates effective immunotherapy. However, microbiota-targeted interventions present promising strategies to enhance immunotherapy outcomes by modulating the gut-liver axis. Overall, this review highlights the emerging evidence on the role of the gut microbiota in CRLM and provides insights into the molecular mechanisms driving the dynamic interactions within the gut-liver axis.

A Mechanistic Study of the Feasibility of Ursodeoxycholic Acid in the Treatment of Colon Adenocarcinoma

Purpose

Bile acids promote the progression of colon adenocarcinoma (COAD), and ursodeoxycholic acid (UDCA) is a key drug in promoting bile acid excretion, but its role in COAD unclear. Our study aims to investigate the relationship between COAD and bile acid metabolism and to assess the feasibility of UDCA for the treatment of COAD.

Methods

Firstly, biological targets closely related to COAD were identified: Based on the cancer genome atlas (TCGA) database, the core genes of COAD were obtained by differential expression analysis and weighted gene-coexpression network analysis (WGCNA), and subjected to gene ontology (GO) function annotation and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Secondly, finding a drug by target, after identifying UDCA as a candidate drug, the feasibility of UDCA in treating COAD was verified in reverse: Using databases to collect potential targets for COAD and UDCA, and the intersecting genes were the potential targets for UDCA to exert anti-tumor effects. Then Autodock was used for molecular docking to analyze the interaction between UDCA and core target proteins. Finally, experimental validation was performed: MTT assay, wound healing, transwell migration, and angiogenesis assays were used to detect the effects of UDCA on cell proliferation, migration, invasion, and neovascularization.

Results

2064 differential genes were screened from TCGA. WGCNA obtained the module most relevant to CRC, containing 493 genes. KEGG analysis found that overlapping genes were mainly concentrated in bile acid metabolic pathways. A total of 26 UDCA anti-tumor targets were obtained in database, and 5 core targets were selected by STRING database and Cytoscape software: TNF, CYP27B1, MDM2, MMP2, CASP3. Molecular docking results showed that UDCA had good binding activity with the core targets. In vitro experiment showed UDCA effectively inhibited the proliferation, migration, invasion and neovascularization in colon cancer cells.

Conclusion

The antitumor activity of ursodeoxycholic acid may be related to cell apoptosis, proliferation, migration and vascular neogenesis.

Multiple Enzymes Expressed by the Gut Microbiota Can Transform Typhaneoside and Are Associated with Improving Hyperlipidemia

The mechanism of multiple enzymes mediated drug metabolism in gut microbiota is still unclear. This study explores multiple enzyme interaction process of typhactyloside (TYP) with gut microbiota and its lipid-lowering pharmacological activity. TYP, with bioavailability of only 2.78%, is an active component of Typha angustifolia L. and Pushen capsules which is clinically treated for hyperlipidemia. The metabolic process of TYP is identified, and key enzymes involved in TYP metabolism are validated through gene knockout and overexpression techniques. Through overexpressing α-rhamnosidase (Rha) in Escherichia coli, TYP is verified to metabolize into isorhamnetin-3-O-neohesperidin (M1) and isorhamnetin-3-O-glucoside (M2) after removing rhamnose through Rha. Besides, knockout of β-glucosidase (Glu) confirms that TYP generates M3 through Glu after removing glucose. Combined with molecular docking, M3 is transformed to generate 3,4-dihydroxyphenylacetic acid (M4), protocatechuic acid (M5), and 3-hydroxyphenylacetic acid (M6) through flavonoid reductase (Flr) and chalcone isomerase (Chi). In conclusion, multiple enzymes involved in TYP metabolism (Rha/Glu→Flr→Chi) are identified. Through in vivo experiments, combined use of M3 and M5 also shows excellent anti-hyperlipidemia efficacy. This is the first study on complex metabolism mechanism and pharmacological activity of natural flavonoids mediated by multiple enzymes, which provide insight to investigate analogous natural products.

Gut microbial-derived N-acetylmuramic acid alleviates colorectal cancer via the AKT1 pathway

BACKGROUND

Gut microbial metabolites are recognised as critical effector molecules that influence the development of colorectal cancer (CRC). Peptidoglycan fragments (PGFs) produced by microbiota play a crucial role in maintaining intestinal homeostasis, but their role in CRC remains unclear.

OBJECTIVE

Here, we aimed to explore the potential contribution of PGFs in intestinal tumourigenesis.

DESIGN

The relative abundance of peptidoglycan synthase and hydrolase genes was assessed by metagenomic analysis. Specific PGFs in the faeces and serum of CRC patients were quantified using targeted mass spectrometry. The effects of PGF on intestinal tumourigenesis were systematically evaluated using various murine models of CRC and organoids derived from CRC patients. Downstream molecular targets were screened and evaluated using proteome microarray, transcriptome sequencing and rescue assays.

RESULTS

Metagenomic analysis across seven independent cohorts (n=1121) revealed a comprehensive reduction in peptidoglycan synthase gene relative abundance in CRC patients. Targeted mass spectrometry identified significant depletion of a specific PGF, N-acetylmuramic acid (NAM) in CRC patients, which decreased as tumours progressed (p<0.001). NAM significantly inhibits intestinal tumourigenesis in various models, including Apc Min/+, AOM/DSS-treated and MC38 tumour-bearing mice. Additionally, NAM inhibits the growth of patient-derived CRC organoids in a concentration-dependent manner. Mechanistically, NAM inhibits the activation of AKT1 by directly binding to it and blocking its phosphorylation, which is a partial mediator of NAM's anticancer effects.

CONCLUSION

The PGF NAM protects against intestinal tumourigenesis by targeting the AKT1 signalling pathway. NAM may serve as a novel potential preventive and therapeutic biomarker against CRC.

Influence of gut microbial metabolites on tumor immunotherapy: mechanisms and potential natural products

In recent years, tumor immunotherapy has made significant breakthroughs in the treatment of malignant tumors. However, individual differences in efficacy have been observed in clinical practice. There is increasing evidence that gut microbial metabolites influence the efficacy of distal tumor immunotherapy via the gut-liver axis, the gut-brain axis and the gut-breast axis, a process that may involve modulating the expression of immune cells and cytokines in the tumor microenvironment (TME). In this review, we systematically explore the relationship between gut microbial metabolites and tumor immunotherapy, and examine the corresponding natural products and their mechanisms of action. The in-depth exploration of this research area will provide new ideas and strategies to enhance the efficacy of tumor immunotherapy and mitigate adverse effects.

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.

The chemical ecology and physiological functions of type I polyketide natural products: the emerging picture

Covering: up to 2024.For many years, the value of complex polyketides lay in their medical properties, including their antibiotic and antifungal activities, with little consideration paid to their native functions. However, more recent evidence gathered from the study of inter-organismal interactions has revealed the influence of these metabolites upon the ecological adaptation and distribution of their hosts, as well as their modes of communication. The increasing number of sequenced genomes and associated transcriptomes has also unveiled the widespread occurrence of the underlying biosynthetic enzymes across all kingdoms of life, and the important contributions they make to physiological events specific to each organism. This review depicts the diversity of roles fulfilled by type I polyketides, particularly in light of studies carried out during the last decade, providing an initial overall picture of their diverse functions.

Fungal Influences on Cancer Initiation, Progression, and Response to Treatment

Fungal dysbiosis is increasingly recognized as a key factor in cancer, influencing tumor initiation, progression, and treatment outcomes. This review explores the role of fungi in carcinogenesis, with a focus on mechanisms such as immunomodulation, inflammation induction, tumor microenvironment remodeling, and interkingdom interactions. Fungal metabolites are involved in oncogenesis, and antifungals can interact with anticancer drugs, including eliciting potential adverse effects and influencing immune responses. Furthermore, mycobiota profiles have potential as diagnostic and prognostic biomarkers, emphasizing their clinical relevance. The interplay between fungi and cancer therapies can affect drug resistance, therapeutic efficacy, and risk of invasive fungal infections associated with targeted therapies. Finally, emerging strategies for modulating mycobiota in cancer care are promising approaches to improve patient outcomes.

Nano-Armed Limosilactobacillus reuteri for Enhanced Photo-Immunotherapy and Microbiota Tryptophan Metabolism against Colorectal Cancer

Despite being a groundbreaking approach to treating colorectal cancer (CRC), the efficacy of immunotherapy is significantly compromised by the immunosuppressive tumor microenvironment and dysbiotic intestinal microbiota. Here, leveraging the superior carrying capacity and innate immunity-stimulating property of living bacteria, a nanomedicine-engineered bacterium, LR-S-CD/CpG@LNP, with optical responsiveness, immune-stimulating activity, and the ability to regulate microbiota metabolome is developed. Immunoadjuvant (CpG) and carbon dot (CD) co-loaded plant lipid nanoparticles (CD/CpG@LNPs) are constructed and conjugated to the surface of Limosilactobacillus reuteri (LR) via reactive oxygen species (ROS)-responsive linkers. The inherent photothermal and photodynamic properties of oral CD/CpG@LNPs induce in situ cytotoxic ROS generation and immunogenic cell death of colorectal tumor cells. The generated neoantigens and the released CpG function as a potent in situ vaccine that stimulates the maturation of immature dendritic cells. The mature dendritic cells and metabolites secreted by LR subsequently facilitated the tumor infiltration of cytotoxic T lymphocytes to eradicate colorectal tumors. The further in vivo results demonstrate that the photo-immunotherapy and intestinal microbial metabolite regulation of LR-S-CD/CpG@LNPs collectively suppressed the growth of orthotopic colorectal tumors and their liver metastases, presenting a promising avenue for synergistic treatment of CRC via the oral route.

Solobacterium moorei promotes tumor progression via the Integrin α2/β1-PI3K-AKT-mTOR-C-myc signaling pathway in colorectal cancer

More and more evidences show that the imbalance of intestinal flora homeostasis can contribute to the progression of colorectal cancer (CRC). Solobacterium moorei (S. moorei), an anaerobic Gram-positive bacillus, was found to be enriched in fecal samples from CRC patients. However, the signaling regulatory mechanism of S. moorei promoting CRC progression remain unknown. Three CRC mouse models (ApcMin/+ mice, AOM/DSS-treated mice and subcutaneous colorectal xenograft mice) and two cell lines (DLD-1 and HT-29) were used to investigate the biological functions and molecular mechanisms of S. moorei on tumor progression of CRC in vivo and in vitro. S. moorei abundance increased in fecal samples and tumor tissues, and was significantly positively correlated with tumor staging of CRC. S. moorei promoted tumor progression in various CRC mouse models and it selectively adhered to cancer cells in comparison to colonic mucosal epithelial cells, enhancing CRC cell proliferation and inhibiting cell apoptosis. Mechanistically, S. moorei cellwall protein Cna B-type domain-containing protein binds to integrin α2/β1 on CRC cells, leading to the activation of PI3K-AKT-mTOR-C-myc pathway via phospho-FAK, thereby promoted tumor cell growth and progression. Blockade of integrin α2/β1 abolished S. moorei-mediated oncogenic response in vitro and in vivo. In summary, this study demonstrated that S. moorei promoted tumor progression via the integrin α2/β1-PI3K-AKT-mTOR-C-myc signaling pathway, which is a novel specific pathogen-mediated mechanism that might be a new potential target for CRC prevention, diagnosis, and treatment.

Sleep Duration, Dietary Inflammatory Potential, and Obesity in Relation to Colorectal Cancer Incidence in the Multiethnic Cohort

BACKGROUND/OBJECTIVES

Colorectal cancer (CRC) is a leading cause of cancer-related morbidity and mortality worldwide. Sleep duration, diet, and obesity have each been identified as modifiable risk factors linked to CRC. However, their joint effect on CRC incidence is underexplored. This study investigated the association between sleep duration and CRC incidence and explored the joint effects of sleep duration, a pro-inflammatory diet, and obesity on CRC incidence in the Multiethnic Cohort (MEC).

METHODS

This prospective cohort study analyzed 193,027 participants from Hawaii and California enrolled in the MEC between 1993 and 1996. Sleep duration was self-reported and categorized as short (≤6 h), normal (7-8 h), or long (≥9 h). Diet was self-reported via FFQ and inflammatory potential was assessed using the energy-adjusted Dietary Inflammatory Index (E-DII). CRC cases were identified via cancer registries. Cox proportional hazards models estimated the hazard ratios (HRs) for CRC risk.

RESULTS

After 23.8 years of follow-up, 5825 CRC cases were identified. A pro-inflammatory diet combined with suboptimal sleep increased CRC risk by 12% (short sleep duration, aHR: 1.12; 95% CI: 1.02-1.24) and 22% (long sleep duration, aHR: 1.22, 95% CI: 1.05-1.43). Furthermore, long sleep duration was associated with a 10% increase in CRC risk (aHR: 1.10; 95% CI: 1.01-1.22) compared with normal sleep, while short sleep showed no significant association overall. Obese individuals with short or long sleep had significantly higher CRC risk (short sleep aHR: 1.35; 95% CI: 1.21-1.51; long sleep aHR: 1.36; 95% CI: 1.14-1.64) compared with non-obese individuals with corresponding sleep durations.

CONCLUSIONS

Long sleep duration and a combination of suboptimal sleep duration and a pro-inflammatory dietary pattern or obesity amplifies the risk.

A comprehensive review of probiotics and human health-current prospective and applications

The beneficial properties of probiotics have always been a point of interest. Probiotics play a major role in maintaining the health of Gastrointestinal Tract (GIT), a healthy digestive system is responsible for modulating all other functions of the body. The effectiveness of probiotics can be enhanced by formulating them with prebiotics the formulation thus formed is referred to as synbiotics. It not only improves the viability and stability of probiotic cells, but also inhibits the growth of pathogenic strains. Lactobacillus and Bifidobacterium spp. are most commonly used as probiotics. The other microbial spp. that can be used as probiotics are Bacillus, Streptococcus, Enterococcus, and Saccharomyces. Probiotics can be used for the treatment of diabetes, obesity, inflammatory, cardiovascular, respiratory, Central nervous system disease (CNS) and digestive disorders. It is also essential to encapsulate live microorganisms that promote intestinal health. Encapsulation of probiotics safeguards them against risks during production, storage, and gastrointestinal transit. Heat, pressure, and oxidation eradicate probiotics and their protective qualities. Encapsulation of probiotics prolongs their viability, facilitates regulated release, reduces processing losses, and enables application in functional food products. Probiotics as microspheres produced through spray drying or coacervation. This technique regulates the release of gut probiotics and provides stress resistance. Natural encapsulating materials including sodium alginate, calcium chloride, gel beads and polysaccharide promoting safeguards in probiotics during the digestive process. However, several methods including, spray drying where liquid is atomized within a heated air chamber to evaporate moisture and produce dry particles that improves the efficacy and stability of probiotics. Additionally, encapsulating probiotics with prebiotics or vitamins enhance their efficacy. Probiotics enhance immune system efficacy by augmenting the generation of antibodies and immunological cells. It combats illnesses and enhances immunity. Recent studies indicate that probiotics may assist in the regulation of weight and blood glucose levels and influence metabolism and insulin sensitivity. Emerging research indicates that the "gut-brain axis" connects mental and gastrointestinal health. Probiotics may alleviate anxiety and depression via influencing neurotransmitter synthesis and inflammation. Investigations are underway about the dermatological advantages of probiotics that forecasting the onsite delivery of probiotics, encapsulation is an effective technique and requires more consideration from researchers. This review focuses on the applications of probiotics, prebiotics and synbiotics in the prevention and treatment of human health.

Fusobacterium nucleatum promotes colorectal cancer liver metastasis via miR-5692a/IL-8 axis by inducing epithelial-mesenchymal transition

BACKGROUND

The association between the intestinal microbiota and colorectal cancer (CRC) has been extensively studied, with Fusobacterium nucleatum (F. nucleatum, FN) being found in high abundance in colorectal cancer tissues. Previous research has emphasized the significant role of F. nucleatum in the occurrence of CRC. However, the impact of F. nucleatum on CRC liver metastasis has not been well understood.

METHODS

The effects of F. nucleatum on metastasis ability of CRC cell were evaluated in vitro were examined by wound-healing assay and transwell assay. The mouse model of CRC liver metastasis was constructed by spleen injection, and the degree of liver metastasis was assessed by in vivo bioluminescence imaging. The gene expression changes in CRC cells after co-culture with F. nucleatum was analyzed through transcriptome sequencing. qRT-PCR and Western Blot assays were performed to validate the expression of related genes and proteins.

RESULTS

The metastasis ability of CRC cells was significantly enhanced after co-culture with F. nucleatum in vitro. In the mouse model, F. nucleatum also promoted the development of liver metastasis in CRC. Mechanistically, F. nucleatum infection increased the expression of IL-8 by downregulated the level of miR-5692a, a regulatory microRNA of IL-8. This led to the activation of the ERK pathway and resulted in the epithelial-mesenchymal transition (EMT) of CRC cells.

CONCLUSIONS

Our results suggest that F. nucleatum promotes CRC liver metastasis by inducing epithelial-mesenchymal transition through the miR-5692a/IL-8 axis. These findings provide new insights for the prevention and treatment of colorectal cancer liver metastasis.

Beneficial microbiome and diet interplay in early-onset colorectal cancer

Colorectal cancer (CRC) is the third most commonly diagnosed cancer and the second leading cause of cancer-related deaths worldwide. Although the risk of developing CRC increases with age, approximately 10% of newly diagnosed cases occur in individuals under the age of 50. Significant changes in dietary habits in young adults since industrialization create a favorable microenvironment for colorectal carcinogenesis. We aim here to shed light on the complex interplay between diet and gut microbiome in the pathogenesis and prevention of early-onset CRC (EO-CRC). We provide an overview of dietary risk factors associated with EO-CRC and contrast them with the general trends for CRC. We delve into gut bacteria, fungi, and phages with potential benefits against CRC and discuss the underlying molecular mechanisms. Furthermore, based on recent findings from human studies, we offer insights into how dietary modifications could potentially enhance gut microbiome composition to mitigate CRC risk. All together, we outline the current research landscape in this area and propose directions for future investigations that could pave the way for novel preventive and therapeutic strategies.

Unravelling the prognostic and operative role of intratumoural microbiota in non-small cell lung cancer: Insights from 16S rRNA and RNA sequencing

BACKGROUND

Complex interrelationships between the microbiota and cancer have been identified by several studies. However, despite delineating microbial composition in non-small cell lung cancer (NSCLC), key pathogenic microbiota and their underlying mechanisms remain unclear.

METHODS

We performed 16S rRNA V3-V4 amplicon and transcriptome sequencing on cancerous and adjacent normal tissue samples from 30 patients with NSCLC, from which clinical characteristics and prognosis outcomes were collected. We used 16S rRNA sequencing to dissect microbial composition and perform prognosis correlations, and in conjunction with transcriptome sequencing, we determined potential mechanisms underpinning significant microbiota actions.

RESULTS

In comparing different sample types, we identified more pronounced beta diversity disparity between NSCLC, lung squamous cell carcinoma (LUSC) and corresponding paired normal tissues. Concurrently, LUSC and lung adenocarcinoma exhibited distinct microbial composition traits at genus levels. Subsequently, four phyla, five classes, nine orders, 17 families and 36 genera were filtered out and were related to prognosis outcomes. Intriguingly, a protective microbial cluster was identified encompassing nine genera associated with delayed disease recurrence, with functional analyses suggested that these microbiota predominantly exerted metabolism-related functions. Additionally, a harmful microbial cluster (HMC) was identified, including three genera. In this HMC and subsequent prognosis model analyses, harmful intratumoural microbiota were potentially implicated in infection, inflammation and immune regulation. Crucially, we identified a microbial genus, Peptococcus, which was as an independent, detrimental NSCLC prognostic factor and potentially impacted prognosis outcomes via tumour necrosis factor (TNF) signalling.

CONCLUSIONS

We identified a substantial connection between intratumoural microbiota and NSCLC prognosis outcomes. Protective microbiota primarily exerted metabolic functions, whereas harmful microbiota were mainly implicated in infection, inflammation and immune modulation. Furthermore, Peptococcus may be significant in adverse NSCLC prognoses and serve as a potential biomarker for patient management and cancer screening.

KEY POINTS

Four phyla, five classes, nine orders, 17 families and 36 genera have been found associated with NSCLC prognosis. We identified a protective microbial cluster associated with delayed recurrence and a harmful microbial cluster related to shorter survival and earlier recurrence. We identified Peptococcus as an independent, detrimental prognostic factor for NSCLC, potentially impacting prognosis via TNF signalling.

Fusobacterium nucleatum in tumors: from tumorigenesis to tumor metastasis and tumor resistance

Fusobacterium nucleatum, an anaerobic Gram-negative bacterium primarily residing in the oral cavity, has garnered significant attention for its emerging role in cancer progression and prognosis. While extensive research has revealed mechanistic links between Fusobacterium nucleatum and colorectal cancer, a comprehensive review spanning its presence and metastatic implications in cancers beyond colorectal origin is conspicuously absent. This paper broadens our perspective from colorectal cancer to various malignancies associated with Fusobacterium nucleatum, including oral, pancreatic, esophageal, breast, and gastric cancers. Our central focus is to unravel the mechanisms governing Fusobacterium nucleatum colonization, initiation, and promotion of metastasis across diverse cancer types. Additionally, we explore Fusobacterium nucleatum's adverse impacts on cancer therapies, particularly within the domains of immunotherapy and chemotherapy. Furthermore, this paper underscores the clinical research significance of Fusobacterium nucleatum as a potential tumor biomarker and therapeutic target, offering a novel outlook on its applicability in cancer detection and prognostic assessment.

Interplay and therapeutic implications of colorectal cancer stem cells, tumor microenvironment, and gut microbiota

This article discusses the interplay between colorectal cancer (CRC) stem cells, tumor microenvironment (TME), and gut microbiota, emphasizing their dynamic roles in cancer progression and treatment resistance. It highlights the adaptability of CRC stem cells, the bidirectional influence of TME, and the multifaceted impact of gut microbiota on CRC. The manuscript proposes innovative therapeutic strategies focusing on these interactions, advocating for a shift towards personalized and ecosystem-targeted treatments in CRC. The conclusion underscores the importance of continued research in these areas for developing effective, personalized therapies.

The Potential of Metabolomics in Colorectal Cancer Prognosis

Colorectal cancer (CRC) is one of the most common cancers worldwide, posing a serious threat to human health. Metabolic reprogramming represents a critical feature in the process of tumor development and progression, encompassing alterations in sugar metabolism, lipid metabolism, amino acid metabolism, and other pathways. Metabolites hold promise as innovative prognostic biomarkers for cancer patients, which is crucial for targeted follow-up care and interventions. This review aims to provide an overview of the progress in research on metabolic biomarkers for predicting the prognosis of CRC. We also discuss the future trends and challenges in this area.

Regulation of bile acids and their receptor FXR in metabolic diseases

High sugar, high-fat diets and unhealthy lifestyles have led to an epidemic of obesity and obesity-related metabolic diseases, seriously placing a huge burden on socio-economic development. A deeper understanding and elucidation of the specific molecular biological mechanisms underlying the onset and development of obesity has become a key to the treatment of metabolic diseases. Recent studies have shown that the changes of bile acid composition are closely linked to the development of metabolic diseases. Bile acids can not only emulsify lipids in the intestine and promote lipid absorption, but also act as signaling molecules that play an indispensable role in regulating bile acid homeostasis, energy expenditure, glucose and lipid metabolism, immunity. Disorders of bile acid metabolism are therefore important risk factors for metabolic diseases. The farnesol X receptor, a member of the nuclear receptor family, is abundantly expressed in liver and intestinal tissues. Bile acids act as endogenous ligands for the farnesol X receptor, and erroneous FXR signaling triggered by bile acid dysregulation contributes to metabolic diseases, including obesity, non-alcoholic fatty liver disease and diabetes. Activation of FXR signaling can reduce lipogenesis and inhibit gluconeogenesis to alleviate metabolic diseases. It has been found that intestinal FXR can regulate hepatic FXR in an organ-wide manner. The crosstalk between intestinal FXR and hepatic FXR provides a new idea for the treatment of metabolic diseases. This review focuses on the relationship between bile acids and metabolic diseases and the current research progress to provide a theoretical basis for further research and clinical applications.

Flavonoids and the gut microbiome: a powerful duo for brain health

Flavonoids, a class of polyphenolic compounds, are widely distributed in plant-based foods and have been recognized for their potential to promote overall health and well-being. Flavonoids in fruits and vegetables offer various beneficial effects such as anti-aging, anticancer, and anti-inflammatory properties. Flavonoids have been extensively studied for their neuroprotective properties, which are attributed to their ability to cross the blood-brain barrier and interact with neural cells. Factors like gut microbiota composition, age, genetics, and diet can impact how well flavonoids are absorbed in the gut. The gut microbiota can enhance the absorption of flavonoids through enzymatic processes, making microbiota composition a key factor influenced by age, genetics, and diet. Flavonoids can modulate the gut microbiota through prebiotic and antimicrobial effects, affecting the production of beneficial microbial metabolites like short-chain fatty acids (SCFAs) such as butyrate, which play a role in brain function and health. The gut microbiome also modulates the immune system, which is critical for preventing neuroinflammation. Additionally, flavonoids can benefit mental and psychological health by influencing anti-inflammatory signaling pathways in brain cells and increasing the absorption of tyrosine and tryptophan, precursors to neurotransmitters like serotonin, dopamine, norepinephrine, adrenaline, and gamma-aminobutyric acid (GABA). The flavonoid-gut microbiome axis is a complex and multifaceted relationship that has significant implications for neurological health. This review will explore how genetic and environmental factors can impact flavonoid absorption and the positive effects of flavonoids on brain health and the gut microbiota network.

Gut microbiota in health and disease: advances and future prospects

The gut microbiota plays a critical role in maintaining human health, influencing a wide range of physiological processes, including immune regulation, metabolism, and neurological function. Recent studies have shown that imbalances in gut microbiota composition can contribute to the onset and progression of various diseases, such as metabolic disorders (e.g., obesity and diabetes) and neurodegenerative conditions (e.g., Alzheimer's and Parkinson's). These conditions are often accompanied by chronic inflammation and dysregulated immune responses, which are closely linked to specific forms of cell death, including pyroptosis and ferroptosis. Pathogenic bacteria in the gut can trigger these cell death pathways through toxin release, while probiotics have been found to mitigate these effects by modulating immune responses. Despite these insights, the precise mechanisms through which the gut microbiota influences these diseases remain insufficiently understood. This review consolidates recent findings on the impact of gut microbiota in these immune-mediated and inflammation-associated conditions. It also identifies gaps in current research and explores the potential of advanced technologies, such as organ-on-chip models and the microbiome-gut-organ axis, for deepening our understanding. Emerging tools, including single-bacterium omics and spatial metabolomics, are discussed for their promise in elucidating the microbiota's role in disease development.

Crosstalk between gut microbiota and tumor: tumors could cause gut dysbiosis and metabolic imbalance

Gut microbiota has a proven link with the development and treatment of cancer. However, the causality between gut microbiota and cancer development is still unknown and deserves exploration. In this study, we aimed to explore the alterations in gut microbiota in murine tumor models and the crosstalk between the tumor and the gut microbiota. The subcutaneous and intravenous murine tumor models using both the colorectal cancer cell line MC38 and lung cancer cell line LLC were constructed. Then fecal samples before and after tumor inoculation were collected for whole metagenomics sequencing. Both subcutaneous and metastatic tumors markedly elevated the α-diversity of the gut microbiota. Relative abundance of Ligilactobacillus and Lactobacillus was reduced after subcutaneously inoculating tumor cells, whereas Bacteroides and Duncaniella were reduced in metastatic tumors, regardless of tumor type. At the species level, Lachnospiraceae bacterium was enriched after both subcutaneous and intravenous tumors inoculation, whereas levels of Muribaculaceae bacterium Isolate-110 (HZI), Ligilactobacillus murinus and Bacteroides acidifaciens reduced. Metabolic function analysis showed that the reductive pentose phosphate cycle, urea cycle, ketone body biosynthesis, ectoine biosynthesis, C4-dicarboxylic acid cycle, isoleucine biosynthesis, inosine 5'-monophosphate (IMP), and uridine 5'-monophosphate (UMP) biosynthesis were elevated after tumor inoculation, whereas the cofactor and vitamin biosynthesis were deficient. Principal coordinates analysis (PCoA) showed that subcutaneous and metastatic tumors partially shared the same effect patterns on gut microbiota. Furthermore, fecal microbiota transplantation revealed that this altered microbiota could influence tumor growth. Taken together, this study demonstrated that both colorectal cancer (MC38) and non-colorectal cancer (LLC) can cause gut dysbiosis and metabolic imbalance, regardless of tumor type and process of tumor inoculation, and this dysbiosis influenced the tumor growth. This research gives novel insights into the crosstalk between tumors and the gut microbiota.

Direct and indirect effects of estrogens, androgens and intestinal microbiota on colorectal cancer

Sex differences in colorectal cancer (CRC) has received considerable research attention recently, particularly regarding the influence of sex hormones and the intestinal microbiota. Estrogen, at the genetic and epigenetic levels, directly inhibits CRC cell proliferation by enhancing DNA mismatch repair, regulating miRNAs, blocking the cell cycle, and modulating ion channels. However, estradiol's activation of GPER promotes oncogene expression. Conversely, androgen contributes to epigenetic dysregulation and CRC progression via nuclear receptors while inducing apoptosis through membrane receptors. Specific gut microorganisms produce genotoxins and oncogenic metabolites that damage colonic cell DNA and contribute to cancer induction. Regarding the tumor microenvironment, estrogen mitigates intestinal inflammation, reverses immunosuppression, increases gut microbiome diversity and commensal bacteria abundance, and decreases pathogen enrichment. On the contrary, androgen disrupts intestinal microecology, diminish immunotherapy efficacy, and exacerbate colonic inflammation and tumor growth. The impact of estrogen and androgen is closely tied to their receptor status, elucidating their dual roles in CRC pathogenesis. This review comprehensively discusses the direct and indirect effects of sex hormones and the intestinal microbiota on CRC, considering environmental factors such as diet and lifestyle to propose novel prevention and treatment strategies.

Modulation of gut microbiota in targeted cancer therapy: insights on the EGFR/VEGF/KRAS pathways

The rise in the incidence of cancer globally has led to a heightened interest in targeted therapies as a form of anticancer treatment. Key oncogenic targets, including epidermal growth factor receptor (EGFR), vascular endothelial growth factor (VEGF), and kirsten rat sarcoma viral oncogene homologue (KRAS), have emerged as focal points in the development of targeted agents. Research has investigated the impact of gut microbiota on the efficacy of various anticancer therapies, such as immunotherapy, chemotherapy, and radiotherapy. However, a notable gap exists in the literature regarding the relationship between gut microbiota and targeted agents. This review emphasizes how specific gut microbiota and gut microbiota metabolites, including butyrate, propionate, and ursodeoxycholic acid, interact with oncogenic pathways to modulate anti-tumor effects. Conversely, deoxycholic acid, lipopolysaccharide, and trimethylamine n-oxide may exert pro-tumor effects. Furthermore, modulation of the gut microbiota influences glucose and lipid metabolism, thereby enhancing the response to anti-KRAS agents and addressing diarrhea induced by tyrosine kinase inhibitors. By elucidating the connection between gut microbiota and the EGFR/VEGF/KRAS pathways, this review provides valuable insights for advancing targeted cancer therapy and optimizing treatment outcomes in clinical settings.

The oral-gut microbiome axis in breast cancer: from basic research to therapeutic applications

As a complicated and heterogeneous condition, breast cancer (BC) has posed a tremendous public health challenge across the world. Recent studies have uncovered the crucial effect of human microbiota on various perspectives of health and disease, which include cancer. The oral-gut microbiome axis, particularly, have been implicated in the occurrence and development of colorectal cancer through their intricate interactions with host immune system and modulation of systemic inflammation. However, the research concerning the impact of oral-gut microbiome axis on BC remains scarce. This study focused on comprehensively reviewing and summarizing the latest ideas about the potential bidirectional relation of the gut with oral microbiota in BC, emphasizing their potential impact on tumorigenesis, treatment response, and overall patient outcomes. This review can reveal the prospect of tumor microecology and propose a novel viewpoint that the oral-gut microbiome axis can be a breakthrough point in future BC studies.

Integrated analysis of microbiota and gut microbial metabolites in blood for breast cancer

Gut microbiota and associated metabolites have been linked to breast carcinogenesis. Evidences demonstrate blood microbiota primarily originates from the gut and may act as a biomarker for breast cancer. We aimed to characterize the microbiota-gut microbial metabolites cross-talk in blood and develop a composite diagnostic panel for breast cancer. We performed 16S rRNA gene sequencing and metabolomics profiling on blood samples from 107 breast cancer cases and 107 age-paired controls. We found that the alpha diversity of the blood microbiota was decreased in breast cancer compared to controls. There were significantly different profiles of microbiota and gut microbial metabolites in blood between these two groups, with nine bacterial genera and four gut microbial metabolites increased in patients, while thirty-nine bacterial genera and two gut microbial metabolites increased in controls. Some breast cancer-associated gut microbial metabolites were linked to differential blood microbiota, and a composite microbiota-metabolite diagnostic panel was further developed with an area under the curve of 0.963 for breast cancer. This study underscored the pivotal role of microbiota and gut microbial metabolites in blood and their interactions for breast carcinogenesis, as well as the potential of a composite diagnostic panel as a non-invasive biomarker for breast cancer.IMPORTANCEOur integrated analysis demonstrated altered profiles of microbiota and gut microbial metabolites in blood for breast cancer patients. The extensive correlation between microbiota and gut microbial metabolites in blood assisted the understanding of the pathogenesis of breast cancer. The good performance of a composite microbiota-gut microbial metabolites panel in blood suggested a non-invasive approach for breast cancer detection and a novel strategy for better diagnosis and prevention of breast cancer in the future.