Gut microbiota in colorectal cancer development and therapy

Advance on the effects of algal carotenoids on inflammatory signaling pathways

The development of inflammation has an indispensable importance in the self-protection of the human body. However, over-inflammation may damage human health, and inflammatory pathways and inflammasomes have a significant impact on the onset of inflammation. Therefore, how to constrain the development of inflammation through inflammatory pathways or inflammasomes becomes a hot research issue. Carotenoids are a natural pigment and an active substance in algae, with anti-inflammatory and antioxidant effects. Many studies have shown that carotenoids have inhibitory effects on the inflammatory pathways and inflammasomes. In this review, we discussed the mechanism of carotenoids targeting those important inflammatory pathways and their effects on common inflammasome NLRP3 and inflammation-related diseases from the perspective of several inflammatory pathways, including p38 MAPK, IL-6/JAK/STAT3, and PI3K, with a focus on the targets and targeting effects of carotenoids on different inflammatory signaling pathways, and at last proposed possible anti-inflammatory targets.

Mechanism of APC truncation involved in colorectal cancer tumorigenesis (Review)

Adenomatous polyposis coli (APC) is widely recognized as a heavily mutated gene that suppresses tumor growth in colorectal cancer (CRC). Its mutation is considered to be the primary and early event that occurs in the development of CRC. In addition, APC has a crucial role in inhibiting the canonical Wnt signaling pathway. APC mutations in CRC result in the production of shortened gene products. This impairment of β-catenin destruction complexes causes an accumulation of active β-catenin in the cytoplasm and nucleus. In these compartments, β-catenin can bind with DNA-binding proteins of the transcription factor/lymphoid enhancer-binding factor family, thereby activating the Wnt signaling pathway. Consequently, the balance of numerous cellular processes is disrupted, ultimately driving the formation of tumors. There is a growing body of evidence indicating the prevalent occurrence of APC truncation in the majority of CRC cases. Furthermore, it has been observed that these truncated proteins have a crucial role in the activation of the Wnt signaling pathway and the subsequent loss of tumor inhibitory function. This review aimed to provide an overview of the recent advancements in understanding the mechanism behind APC truncation and its association with the onset and progression of CRC.

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 role of cGAS-STING signaling pathway in colorectal cancer immunotherapy: Mechanism and progress

Colorectal cancer (CRC) is a common malignant tumor in the gastrointestinal tract, it is known as the "silent killer", which poses a serious threat to the lives of patients. The cyclic GMP-AMP synthase (cGAS)-stimulator of interferon gene (STING) signaling pathway responds to DNA by sensing, which plays an important role in anti-infection, autoimmune diseases and anti-tumor immunity. Recent studies have found that the activation of cGAS-STING pathway in CRC can induce the expression and secretion of type I interferon (IFN-I) and a variety of inflammatory factors, further activate anti-tumor CD8+ T cells, exert anti-tumor immune response, and inhibit the progression of CRC. Therefore, targeting the cGAS-STING pathway and developing drugs that can regulate the cGAS-STING pathway are of great significance for improving the therapeutic effect and prognosis of CRC patients. In this review, we introduce the cGAS-STING signaling pathway and the regulatory role of this signaling pathway in CRC immune microenvironment. In addition, we discussed the research progress of cGAS-STING pathway in CRC immunotherapy and the clinical research status of STING agonists developed against this pathway, emphasizing the clinical potential of CRC immunotherapy based on the cGAS-STING signaling pathway.

Causal relationship between gut microbiota and lung squamous cell carcinoma: a bidirectional two-sample Mendelian randomization study

PURPOSE

This study aims to explore the potential causal relationship between gut microbiota and lung squamous cell carcinoma (LUSC).

METHODS

A bidirectional two-sample Mendelian randomization analysis was conducted using genome-wide association study (GWAS) data from gut microbiota and LUSC. Gut microbiota served as the exposure factor, with instrumental variables selected from a GWAS involving 18 340 participants. LUSC data were drawn from a European cohort including 29 266 LUSC cases and 56 450 controls. Inverse-variance weighted (IVW) method was used as the primary method, with the Benjamini-Hochberg method applied to adjust for multiple comparisons. An independent dataset (ieu-a-967, containing 3275 LUSC cases and 15 038 controls) was used for replication analysis to ensure robustness.

RESULTS

IVW analysis found that Butyricicoccus (OR = 0.79, 95% CI: 0.63-0.99, P = .042) and Coprobacter (OR = 0.85, 95% CI: 0.74-0.97, P = .018) were significantly protective against LUSC. In contrast, Victivallis (OR = 1.11, 95% CI: 1.00-1.23, P = .045) and Ruminococcus (OR = 1.28, 95% CI: 1.03-1.60, P = .028) increased LUSC risk. Replication analysis in the independent dataset confirmed significant associations for Ruminococcus and Coprobacter. No reverse causality or pleiotropy was detected.

CONCLUSION

This study provides evidence of a causal relationship between specific gut microbiota and LUSC risk, highlighting new microbial targets for potential prevention and treatment strategies in lung cancer. Key messages What is already known on this topic?  Previous studies have suggested potential links between gut microbiota composition and the development of various cancers, including lung cancer. However, the exact causal relationship between specific gut microbiota and lung squamous cell carcinoma (LUSC) has remained unclear. Traditional observational studies have struggled to determine the direction of causality due to confounding factors, making further investigation necessary through more robust methods such as Mendelian randomization (MR). What this study adds?  This bidirectional MR study provides novel genetic evidence indicating that certain gut microbiotas are causally associated with LUSC risk. Specifically, Butyricicoccus appears to reduce the risk of LUSC, while Victivallis increases the risk. These findings highlight the role of the gut-lung axis in LUSC and open up new avenues for exploring gut microbiota as potential modulators of lung cancer risk. How this study might affect research, practice, or policy?  The implications of this study may significantly influence future research into cancer prevention strategies by targeting gut microbiota. Additionally, it could inform clinical practices aimed at modulating gut microbiota to lower the risk of LUSC, potentially influencing dietary or probiotic interventions to reduce cancer susceptibility. Furthermore, these results might shape public health policies that focus on the gut-lung axis as a novel avenue for cancer prevention and management.

Yanghe decoction inhibits inflammation-induced lung metastasis of colorectal cancer

ETHNOPHARMACOLOGICAL RELEVANCE

Positive deficiency and cancer toxicity are the main pathogenesis of colorectal cancer (CRC) lung metastasis. Yanghe decoction (YHD), a traditional Chinese medicine, has the effects of warming yang, tonifying blood, dispersing cold and clearing stagnation, adopting a treatment method that combines supporting the right and dispelling the wrong, which has remarkable efficacy in anti-tumor.Although, its precise mechanism of inhibiting the metastasis of colorectal cancer to the lung is still poorly understood.

AIM OF THE STUDY

This study aimed to elucidate the antitumor properties of YHD within the context of colorectal cancer lung metastasis.

MATERIALS AND METHODS

Ultrahigh-performance liquid chromatography coupled with mass spectrometry (UHPLC-MS) was utilized to analyze the chemical composition of YHD. The anticancer activity of YHD was evaluated in a CRC lung metastasis mouse model by quantifying pulmonary metastatic nodules. The effects of YHD on CRC cell proliferation, apoptosis, cell cycle progression, and invasion were assessed using CCK-8 assays, flow cytometry, and Transwell assays. YHD-mediated immune modulation in tumor-bearing mice was evaluated by analyzing antitumor immunity, immunosuppressive cells, and cytokines in peripheral blood and tumor tissue. Gut microbiota analysis was conducted to determine the impact of YHD on the gut microbiota in mice.

RESULTS

Our analysis identified 1801 chemical markers in YHD. CFA exacerbated lung metastasis in CRC, whereas oral administration of YHD significantly mitigated this effect, as evidenced by the reduced number of metastatic lung nodules in CRC tumor-bearing mice. In vitro experiments demonstrated that YHD inhibits CRC cell proliferation, induces apoptosis, and suppresses invasion. In the lung tissues of mice with CRC metastasis treated with CFA, there was a significant reduction in NK cells and IL-21, along with an increase in M2 macrophages and IL-6. Following YHD treatment, there was a notable increase in NK cells and IL-21, accompanied by a decrease in M2 macrophages and IL-6 in lung tissues. YHD administration was also associated with an increase in beneficial bacterial species such as Bacillus and a decrease in deleterious bacterial species such as Oscillibacter.

CONCLUSION

Our findings demonstrate that YHD inhibits lung metastasis in CRC by suppressing CRC cell proliferation and invasion, in addition to modulating the tumor microenvironment to favor antitumor immunity. These results provide a scientific basis for the clinical application of YHD in the treatment of CRC patients.

Identification of biomarkers related to Escherichia coli infection for the diagnosis of gastrointestinal tumors applying machine learning methods

Background

Escherichia coli (E. coli) is a part of normal gastrointestinal microbiota but it could also cause human gastrointestinal diseases. Understanding the mechanism of E. coli in the progression of gastrointestinal tumors can provide novel prevention and treatment strategies for gastrointestinal tumors.

Methods

The E. coli infection score was calculated by single sample GSEA (ssGSEA). Weighted correlation network analysis (WGCNA) and differentially expressed genes (DEGs) analysis were used to identify genes related to E. coli infection in gastrointestinal tumors. Hub genes were selected by machine learning methods to establish a diagnostic model. The diagnostic performance of the model was evaluated by the area under the receiver operating characteristic (ROC) curve (AUC) and validated in three external datasets. After determining the biomarkers, immune infiltration analysis and GSEA were further performed. The mRNA expressions of the biomarkers in stomach adenocarcinoma (STAD) cells and the invasion and migration of the tumor cells were detected by conducting in vitro experiments.

Results

The E. coli infection score was lower in tumor samples than in normal samples. Eight hub genes were selected from a total of 28 genes associated with E. coli-related dysbiosis in gastrointestinal tumors to establish an accurate diagnostic model. The AUC values of PRKCB and IL16 were all greater than 0.7 in three external datasets and the mRNA expression pattern was consistent with TCGA cohort, therefore PRKCB and IL16 were selected as the diagnostic biomarkers. PRKCB and IL16 exhibited significant positive correlations with most immune cells, and inflammation-related pathways were activated in the high expression groups of PRKCB and IL16. Moreover, IL16 was high-expressed but PRKCB was low-expressed in STAD cells, and silencing IL16 suppressed the invasion and migration of STAD cells.

Conclusions

Overall, we identified and validated 8 robust genes related to E. coli applying bioinformatics and machine learning algorithms, providing theoretical foundations for the relationship between E. coli-related dysbiosis and gastrointestinal tumors.

LRP11-AS1 mediates enterotoxigenic Bacteroides fragilis-related carcinogenesis in colorectal Cancer via the miR-149-3p/CDK4 pathway

Long noncoding RNAs (lncRNAs) are critical in tumorigenesis and show potential for tumor diagnosis and therapy. Enterotoxigenic Bacteroides fragilis (ETBF), known for producing enterotoxins, is implicated in human gut tumorigenesis, yet the underlying mechanisms are not fully elucidated. This study aims to clarify the molecular mechanisms by which lncRNAs contribute to ETBF-induced tumorigenesis, with a focus on LRP11-AS1's role in modulating ETBF's colorectal carcinogenesis. We found a marked increase in LRP11-AS1 expression in colorectal cancer (CRC) tissues compared to adjacent non-tumorous tissues. In vitro, CRC cells exposed to ETBF showed elevated LRP11-AS1 levels. Mechanistically, LRP11-AS1 was shown to enhance CDK4 expression by competitively binding to miR-149-3p. These results indicate that LRP11-AS1 may facilitate ETBF-related carcinogenesis in CRC and could serve as a therapeutic target and diagnostic biomarker for ETBF-associated CRC.

Compound Probiotics Improve Neuropathic Pain Prognosis in a Murine Model of Chronic Constriction Injury

Purpose

Compound probiotics have been reported to ameliorate imbalances in the intestinal flora that may play a critical role in neuropathic pain. This study aimed to investigate the efficacy of compound probiotic treatment on neuropathic pain.

Methods

Thirty mice were randomly divided into three groups: 1) sham group, 2) mouse with chronic constrictive injury (CCI), and 3) probiotic gavage with CCI (CCI+Prob). The degree of pain and gait recovery was assessed by Mechanical withdrawal threshold (MWT), thermal withdrawal latency (TWL), and mouse footprints. The degree of atrophy of the gastrocnemius muscle was assessed by muscle weight, hematoxylin and eosin (H&E) staining. Gut microbiota were analyzed by 16S ribosomal RNA sequencing (16SrRNA).

Results

Four weeks after surgery, TWL and MWT assessment showed significant increases in the CCI+Prob group compared with the CCI group (P < 0.01). Gait analysis results as well as gastrocnemius muscle weight showed a significant improvement in the CCI+Prob group compared with the CCI group. Measurement of alpha diversity showed a significant increase in the CCI group compared with the sham group, but this increase was attenuated by probiotic intervention in the CCI+Prob group. Although the CCI group had significantly decreased levels of Akkermansia and significantly increased levels of Ruminococcaceae, probiotic treatment reversed these changes.

Conclusion

Compound probiotics treatment can improve the pain and muscle atrophy in mice with CCI-induced neuropathic pain. The improvement of symptoms is associated with changes in the composition of gut microbiota.

The oncomicrobiome: New insights into microorganisms in cancer

The discoveries of the oncomicrobiome (intratumoral microbiome) and oncomicrobiota (intratumoral microbiota) represent significant advances in tumor research and have rapidly become of key interest to the field. Within tumors, microorganisms such as bacteria, fungi, viruses, and archaea form the oncomicrobiota and are primarily found within tumor cells, immunocytes, and the intercellular matrix. The oncomicrobiome exhibits marked heterogeneity and is associated with tumor initiation, progression, metastasis, and treatment response. Interactions between the oncomicrobiome and the immune system can modulate host antitumor immunity, influencing the efficacy of immunotherapies. Oncomicrobiome research also faces numerous challenges, including overcoming methodological issues such as low target abundance, susceptibility to contamination, and biases in sample handling and analysis methods across different studies. Furthermore, studies of the oncomicrobiome may be confounded by baseline differences in microbiomes among populations driven by both environmental and genetic factors. Most studies to date have revealed associations between the oncomicrobiome and tumors, but very few have established mechanistic links between the two. This review introduces the relevant concepts, detection methods, sources, and characteristics of the oncomicrobiome. We then describe the composition of the oncomicrobiome in common tumors and its role in shaping the tumor microenvironment. We also discuss the current problems and challenges to be overcome in this rapidly progressing field.

An Empirical Dietary Pattern Associated With the Gut Microbial Features in Relation to Colorectal Cancer Risk

BACKGROUND & AIMS

Epidemiologic evidence for dietary influence on colorectal cancer (CRC) risk through the gut microbiome remains limited.

METHODS

Leveraging 307 men and 212 women with stool metagenomes and dietary data, we characterized and validated a sex-specific dietary pattern associated with the CRC-related gut microbial signature (CRC Microbial Dietary Score [CMDS]). We evaluated the associations of CMDS with CRC risk according to Fusobacterium nucleatum, pks+Escherichia coli, and enterotoxigenic Bacteroides fragilis status in tumor tissue using Cox proportional hazards regression in the Health Professionals Follow-Up Study (1986-2018), Nurses' Health Study (1984-2020), and Nurses' Health Study II (1991-2019).

RESULTS

The CMDS was characterized by high industrially processed food and low unprocessed fiber-rich food intakes. In 259,200 participants, we documented 3854 incident CRC cases over 6,467,378 person-years of follow-up. CMDS was associated with a higher risk of CRC (Ptrend < .001), with a multivariable hazard ratio (HRQ5 vs Q1) of 1.25 (95% CI, 1.13-1.39). The association remained after adjusting for previously established dietary patterns, for example, the Western and prudent diets. Notably, the association was stronger for tumoral F nucleatum-positive (HRQ5 vs Q1, 2.51; 95% CI, 1.68-3.75; Ptrend < .001; Pheterogeneity = .03, positivity vs negativity), pks+E coli-positive (HRQ5 vs Q1, 1.68; 95% CI, 0.84-3.38; Ptrend = .005; Pheterogeneity = .01, positivity vs negativity), and enterotoxigenic Bacteroides fragilis-positive CRC (HRQ5 vs Q1, 2.06; 95% CI, 1.10-3.88; Ptrend = .016; Pheterogeneity = .06, positivity vs negativity), compared with their negative counterparts.

CONCLUSIONS

CMDS was associated with increased CRC risk, especially for tumors with detectable F nucleatum, pks+E coli, and enterotoxigenic Bacteroides fragilis in tissue. Our findings support a potential role of the gut microbiome underlying the dietary effects on CRC.

The role of Fusobacterium nucleatum in the pathogenesis of colon cancer

Previously, many studies have reported changes in the gut microbiota of patients with colorectal cancer (CRC). While CRC is a well-described disease, the relationship between its development and features of the intestinal microbiome is still being understood. Evidence linking Fusobacterium nucleatum enrichment in colorectal tumor tissue has prompted the elucidation of various molecular mechanisms and tumor-promoting attributes. In this review we highlight various aspects of our understanding of the relationship between the development of CRC and the alteration of intestinal microbiome, focusing specifically on the role of F. nucleatum. As the amount of F. nucleatum DNA in CRC tissue is associated with shorter survival, it may potentially serve as a prognostic biomarker, and most importantly may open the door for a role in CRC treatment.

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.

Intratumoral Bacteria are Uncommon in Gastrointestinal Stromal Tumor

BACKGROUND

Gastrointestinal stromal tumor (GIST) is the most common human sarcoma with over 5000 new patients diagnosed in the USA each year. The tumor originates from the interstitial cells of Cajal and forms an intramural lesion most commonly in the stomach or small intestine. The gut microbiome has been linked to other gastrointestinal cancers and a recent paper purported that GISTs contain substantial intratumoral bacteria. The purpose of this study is to further evaluate the presence of bacteria in GISTs.

PATIENTS AND METHODS

We collected 25 tumor samples of varying size and location from 24 patients under sterile conditions in the operating room immediately following surgical resection. 16S quantitative polymerase chain reaction (qPCR) and 16S ribosomal RNA (rRNA) gene amplicon sequencing were performed to evaluate the bacterial species present in each tumor. Retrospective chart review was performed to determine tumor characteristics, including tumor size, location, imatinib exposure, and mucosal involvement.

RESULTS

In 23 of the 25 tumor samples, there were fewer than 100 copy numbers of 16S rRNA per uL, indicating an absence of a significant bacterial load. 16S rRNA gene amplicon sequencing of the remaining two samples, one gastric tumor and one duodenal tumor, revealed the presence of normal intestinal bacteria. These two tumors, along with three others, had disruption of the mucosal lining.

CONCLUSIONS

GISTs generally lack substantial bacteria, except in some cases when the tumor disrupts the mucosa.

Mendelian randomization and bioinformatics unveil potential links between gut microbial genera and colorectal cancer

Background

Colorectal cancer (CRC) poses a significant global health burden, with high incidence and mortality rates. Despite advances in diagnostic and therapeutic modalities, early diagnosis remains critical for improved outcomes. Recent research has realized the important role of gut microbiota in CRC development, highlighting the need to elucidate potential relationships.

Methods

In this study, we employed Mendelian randomization (MR) to establish a robust potential link between gut microbial genera and CRC. Data from the MiBioGen database provided curated genome-wide association study (GWAS) summary datasets for microbial genera, while the Finngen database provided CRC outcome data. Instrumental variables (IVs) were identified based on genetic variants associated with gut microbiota. Various MR methods, including Inverse Variance Weighted (IVW), Weighted Median, Weighted Mode, Simple Mode, and MR-Egger, were employed to estimate potential effects. Functional analysis of genes near single nucleotide polymorphisms (SNPs) was performed to unravel potential pathways.

Results

Analysis of microbial genera identified five potentially associated with CRC: Eubacterium fissicatena group, Anaerofilum, Defluviitaleaceae UCG011, Ruminococcus 2, and Sutterella. Notably, Defluviitaleaceae UCG011 emerged as the only risk factor. Gene analysis revealed hub genes PTPRD and DSCAM near Defluviitaleaceae UCG011 associated SNPs. Expression analysis showed that PTPRD decreased in colon cancer and DSCAM decreased in rectal cancer. The methylation status of the PTPRD gene promoter region indicated potential regulatory alterations.

Conclusion

This study establishes a potential relationship between five specific gut microbial genera, particularly Defluviitaleaceae UCG011, and CRC. Hub genes PTPRD and DSCAM provide insights into potential molecular mechanisms, suggesting the potential role of Defluviitaleaceae UCG011 in modulating the initiation and progression of CRC. Further research is essential to validate these associations and delve deeper into therapeutic implications.

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.

Unraveling the role of gut microbiota and immune cells in thyroid cancer and tumor drug resistance

The gut microbiota (GM) and immune cells (IC) are increasingly recognized as key players in cancer development and progression. This study aimed to explore the potential mediating role of IC in the causal relationship between GM and thyroid cancer (TC) using Mendelian randomization (MR) analysis. Data from genome-wide association studies (GWAS) encompassing 473 GM species, 731 IC types, and TC were utilized. MR analysis identified nine GM species with significant causal relationships to TC, mediated by 10 IC phenotypes such as "Switched Memory AC," "IgD-CD38dim AC," and "EM DN (CD4-CD8-) AC." These findings suggest a complex interplay where specific IC mediate the effects of GM on TC risk. Sensitivity analyses confirmed the robustness of these results, with no evidence of horizontal pleiotropy. This study highlights potential mechanisms linking GM and IC to TC, offering insights that could inform GM-based immunotherapeutic strategies and IC-targeted interventions. However, further experimental research is needed to validate these causal pathways and better understand the underlying biological mechanisms.

Leflunomide-Induced Weight Loss: Involvement of DAHPS Activity and Synthesis of Aromatic Amino Acids

Background/Objectives: Leflunomide, an isoxazole immunosuppressant, is widely used in the treatment of diseases such as rheumatoid arthritis (RA) and psoriatic arthritis (PsA) as well as lupus nephritis (LN). In recent years, clinical data have shown that some patients have obvious weight loss, liver injury, and other serious adverse reactions after taking leflunomide. However, the causes and mechanisms by which leflunomide reduces weight are unclear. Methods: Therefore, we used a mouse animal model to administer leflunomide, and we observed that the weight of mice in the leflunomide experimental group was significantly reduced (p < 0.01). In this animal experiment, a metabolomic method was used to analyze the livers of the mice in the experimental group and found that the main difference in terms of metabolic pathways was in the metabolism of aromatic amino acids, and it was confirmed that leflunomide can inhibit the limitations of phenylalanine, tyrosine, and tryptophan biosynthesis. Results: Our study revealed that leflunomide inhibited the activity of DAHPS in the gut microbiota, disrupting the metabolism of phenylalanine, tyrosine, and tryptophan, as well as the metabolism of carbohydrates and lipids. Leflunomide also increased endoplasmic reticulum stress by activating the PERK pathway, thereby promoting CHOP expression and increasing apoptosis-induced liver damage. Conclusions: These effects may be related to the observed weight loss induced by leflunomide.

Gut metatranscriptomics based de novo assembly reveals microbial signatures predicting immunotherapy outcomes in non-small cell lung cancer

BACKGROUND

Advanced-stage non-small cell lung cancer (NSCLC) poses treatment challenges, with immune checkpoint inhibitors (ICIs) as the main therapy. Emerging evidence suggests the gut microbiome significantly influences ICI efficacy. This study explores the link between the gut microbiome and ICI outcomes in NSCLC patients, using metatranscriptomic (MTR) signatures.

METHODS

We utilized a de novo assembly-based MTR analysis on fecal samples from 29 NSCLC patients undergoing ICI therapy, segmented according to progression-free survival (PFS) into long (> 6 months) and short (≤ 6 months) PFS groups. Through RNA sequencing, we employed the Trinity pipeline for assembly, MMSeqs2 for taxonomic classification, DESeq2 for differential expression (DE) analysis. We constructed Random Forest (RF), Support Vector Machine (SVM), and Extreme Gradient Boosting (XGBoost) machine learning (ML) algorithms and comprehensive microbial profiles.

RESULTS

We detected no significant differences concerning alpha-diversity, but we revealed a biologically relevant separation between the two patient groups in beta-diversity. Actinomycetota was significantly overrepresented in patients with short PFS (vs long PFS, 36.7% vs. 5.4%, p < 0.001), as was Euryarchaeota (1.3% vs. 0.002%, p = 0.009), while Bacillota showed higher prevalence in the long PFS group (66.2% vs. 42.3%, p = 0.007), when comparing the abundance of corresponding RNA reads. Among the 120 significant DEGs identified, cluster analysis clearly separated a large set of genes more active in patients with short PFS and a smaller set of genes more active in long PFS patients. Protein Domain Families (PFAMs) were analyzed to identify pathways enriched in patient groups. Pathways related to DNA synthesis and Translesion were more enriched in short PFS patients, while metabolism-related pathways were more enriched in long PFS patients. E. coli-derived PFAMs dominated in patients with long PFS. RF, SVM and XGBoost ML models all confirmed the predictive power of our selected RNA-based microbial signature, with ROC AUCs all greater than 0.84. Multivariate Cox regression tested with clinical confounders PD-L1 expression and chemotherapy history underscored the influence of n = 6 key RNA biomarkers on PFS.

CONCLUSION

According to ML models specific gut microbiome MTR signatures' associate with ICI treated NSCLC outcomes. Specific gene clusters and taxa MTR gene expression might differentiate long vs short PFS.

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.

Towards precision medicine: design considerations for nanozymes in tumor treatment

Since the discovery of Fe3O4 nanoparticles with enzyme-like activity in 2007, nanozymes have emerged as a promising class of catalysts, offering advantages such as high catalytic efficiency, low cost, mild reaction conditions, and excellent stability. These properties make nanozymes highly suitable for large-scale production. In recent years, the convergence of nanomedicine and nanocatalysis has highlighted the potential of nanozymes in diagnostic and therapeutic applications, particularly in tumor therapy. Despite these advancements, the clinical translation of nanozymes remains hindered by the lack of designs tailored to specific tumor characteristics, limiting their effectiveness in targeted therapy. This review addresses the mechanisms by which nanozymes induce cell death in various tumor types and emphasizes the key design considerations needed to enhance their therapeutic potential. By identifying the challenges and opportunities in the field, this study aims to provide a foundation for future nanozyme development, ultimately contributing to more precise and effective cancer treatments.

The causal relationship between gut microbiota and 2 neoplasms, malignant and benign neoplasms of bone and articular cartilage: A two-sample Mendelian randomization study

Previous research has demonstrated a close connection between the development of bone neoplasms and variations in the abundance of specific gut microbiota. It remains unclear, however, how the gut microbiota and bone neoplasms are causally related. Hence, in our study, we aim to clarify this relationship between gut microbiota and 2 neoplasms, malignant neoplasm of bone and articular cartilage (MNBAC) and benign neoplasm of bone and articular cartilage (BNBAC), by employing a two-sample Mendelian randomization (MR) approach. In this study, single nucleotide polymorphisms (SNPs) from genome-wide association studies-pooled data related to bone neoplasms and gut microbiota abundance were evaluated. The inverse variance weighted was employed as the major method for assessing the aforementioned causal relationship. Furthermore, the horizontal multiplicity was evaluated utilizing the Mendelian randomization pleiotropy residual sum and outlier and the MR-Egger intercept test. Finally, inverse MR analysis was performed to assess reverse causality. Inverse variance weighted results indicate a potential genetic relationship between 4 gut microbiota and MNBAC, and 3 gut microbiota and BNBAC. On the one hand, Eubacterium eligens group (OR = 0.16, 95% CI = 0.04-0.67, P = .01), Odoribacter (OR = 0.23, 95% CI = 0.06-0.84, P = .03), Slackia (OR = 0.35, 95% CI = 0.13-0.93, P = .04), and Tyzzerella3 (OR = 0.44, 95% CI = 0.24-0.82, P = .01) exhibited a protective effect against MNBAC. On the other hand, of the 3 gut microbes identified as potentially causally related to BNBAC, Oscillibacter (OR = 0.79, 95% CI = 0.63-0.98, P = .03) and Ruminococcus torques group (OR = 0.62, 95% CI = 0.39-0.98, P = .04) were regarded as protective strains of B, while Eubacterium ruminantium group (OR = 1.24, 95% CI = 1.04-1.47, P = .02) was considered to be a risk factor for increasing the incidence of BNBAC. Additionally, the bone neoplasms were not found to have a reverse causal relationship with the above 7 gut microbiota taxa. Four gut microbiota showed causal effects on MNBAC, and 3 gut microbiota demonstrated causality in BNBAC, providing insights into the design of future interventions to reduce the burden of neoplasms.

Narrative Review: Advancing Dysbiosis Treatment in Onco-Hematology with Microbiome-Based Therapeutic Approach

This review explores the complex relationship between gut dysbiosis and hematological malignancies, focusing on graft-versus-host disease (GvHD) in allogeneic hematopoietic stem cell transplantation (allo-HSCT) recipients. We discuss how alterations in microbial diversity and composition can influence disease development, progression, and treatment outcomes in blood cancers. The mechanisms by which the gut microbiota impacts these conditions are examined, including modulation of immune responses, production of metabolites, and effects on intestinal barrier function. Recent advances in microbiome-based therapies for treating and preventing GvHD are highlighted, with emphasis on full ecosystem standardized donor-derived products. Overall, this review underscores the growing importance of microbiome research in hematology-oncology and its potential to complement existing treatments and improve outcomes for thousands of patients worldwide.

Deciphering the role of host-gut microbiota crosstalk via diverse sources of extracellular vesicles in colorectal cancer

Colorectal cancer is the most common type of cancer in the digestive system and poses a major threat to human health. The gut microbiota has been found to be a key factor influencing the development of colorectal cancer. Extracellular vesicles are important mediators of intercellular communication. Not only do they regulate life activities within the same individual, but they have also been found in recent years to be important mediators of communication between different species, such as the gut microbiota and the host. Their preventive, diagnostic, and therapeutic value in colorectal cancer is being explored. The aim of this review is to provide insights into the complex interactions between host and gut microbiota, particularly those mediated through extracellular vesicles, and how these interactions affect colorectal cancer development. In addition, the potential of extracellular vesicles from various body fluids as biomarkers was evaluated. Finally, we discuss the potential, challenges, and future research directions of extracellular vesicles in their application to colorectal cancer. Overall, extracellular vesicles have great potential for application in medical processes related to colorectal cancer, but their isolation and characterization techniques, intercellular communication mechanisms, and the effectiveness of their clinical application require further research and exploration.

Early Onset Colorectal Cancer: Molecular Underpinnings Accelerating Occurrence

The onset of colorectal cancer (CRC) in patients younger than 50 continues to rapidly increase. This study highlights the epidemiologic changes, risk factors, clinical characteristics, and molecular profiles prevalent in early onset CRC patients, and identifies key areas for future research. It has been noted that only a small fraction of early onset CRC cases is attributed to known hereditary mutations and fit the canonical pathway of late-onset colorectal cancer development. To highlight this, we review the genetic and epigenetic modifications specific to early onset CRC. We also discuss the synergetic effect of single-nucleotide polymorphisms and environmental factors on the early onset of CRC. Additionally, we discuss the potential of noninvasive biomarker assays to enhance early detection, screening, diagnosis, and prognostic outcome predictions.

Involvement of autophagy and gut dysbiosis in ambient particulate matter-induced colonic inflammation

Ambient fine particulate matter (PM2.5), a vital environmental toxicant, not only adversely affects the cardiovascular and respiratory systems but also potentially exhibits an association with intestinal inflammation and colorectal cancer (CRC). The underlying molecular mechanisms of PM2.5 impacts on CRC are still unclear. In this study, we utilized collected ambient PM2.5 and standard reference material SRM2786 to investigate the toxic effects on the colon through in vivo chronic exposure mouse and in vitro cell culture models. We employed a chronic mouse exposure model to clarify the colonic injury and gut microbiome biomarkers. Prolonged exposure to PM2.5 via oropharyngeal aspiration led to a significant rise in colonic epithelial proliferation and reduced colon length in mice. It triggered characteristics indicative of gut microbiota dysbiosis linked to inflammatory bowel disease. The gut microbiome alternations may serve as a biomarker indicating the colonic health impacts of PM2.5 exposure. PM2.5 and SRM2786-induced cytotoxicity manifested as autophagy dysregulation-mediated abnormal proliferation, IL-8 production, p62/SQSTM1 accumulation, and lysosomal membrane damage in human colon cells WiDr and Caco-2. Both PM2.5 and SRM2786 exposures led to the accumulation of p62/SQSTM1 and compromised lysosomal membrane integrity, showing impaired autophagic flux in WiDr and Caco-2 cells. Finally, we examined the correlations between atmospheric PM2.5 data and biomarkers of colonic inflammation in human population. The serum level of IL-8 was significantly correlated with regional anthropogenic pollutants. In conclusion, our findings elucidate that ambient PM2.5 exhibits adverse effects on colon health manifested as inflammation, aberrant proliferation, and gut dysbiosis, potentially mediated through autophagy dysregulation, thereby highlighting the importance of further research on the impact of environmental pollutants on gastrointestinal health.

The impact of long-term (≥5 years) cholecystectomy on gut microbiota changes and its influence on colorectal cancer risk: based on 16S rDNA sequencing analysis

BACKGROUND

Colorectal cancer (CRC) continues to be a major global health concern. Recent advances in molecular biology have highlighted the gut microbiota's role in CRC. This study investigates long-term (≥5 years) gut microbiota changes in patients postcholecystectomy, comparing them with CRC patients and healthy controls to assess their impact on CRC development.

METHODS

Sixty participants were divided into three groups: 20 healthy controls, 20 postcholecystectomy (PCE) patients, and 20 CRC patients. Demographic data and stool samples were collected. Gut microbiota composition, abundance, and diversity were analyzed using high-throughput 16S rDNA sequencing.

RESULTS

Significant differences in microbial community, α-diversity ( P  < 0.05) and β-diversity ( P  = 0.006), were observed among the three groups. At the phylum level, Firmicutes abundance was significantly reduced in PCE and CRC groups compared with the control group ( P  = 0.002), while changes in other phyla were not significant ( P >0.05). At the genus level, Bacteroides , Dialister , and Parabacteroides increased progressively from control to PCE to CRC groups ( P  = 0.004, 0.001, and 0.002). Prevotella decreased across these groups ( P  = 0.041). Faecalibacterium and Roseburia abundances were reduced in PCE and CRC groups compared with controls ( P  = 0.001 and 0.003). The Random Forest algorithm identified Parabacteroides , Bacteroides , Roseburia , and Dialister as key distinguishing genera.

CONCLUSION

The gut microbiota of long-term (≥5 years) PCE patients significantly differs from that of controls and resembles that of CRC patients, suggesting a potential link between cholecystectomy and CRC development through key microbial changes.

Metabolic interactions of host-gut microbiota: New possibilities for the precise diagnosis and therapeutic discovery of gastrointestinal cancer in the future-A review

Gastrointestinal (GI) cancer continues to pose a significant global health challenge. Recent advances in our understanding of the complex relationship between the host and gut microbiota have shed light on the critical role of metabolic interactions in the pathogenesis and progression of GI cancer. In this study, we examined how microbiota interact with the host to influence signalling pathways that impact the formation of GI tumours. Additionally, we investigated the potential therapeutic approach of manipulating GI microbiota for use in clinical settings. Revealing the complex molecular exchanges between the host and gut microbiota facilitates a deeper understanding of the underlying mechanisms that drive cancer development. Metabolic interactions hold promise for the identification of microbial signatures or metabolic pathways associated with specific stages of cancer. Hence, this study provides potential strategies for the diagnosis, treatment and management of GI cancers to improve patient outcomes.

The role of microbiota in nasopharyngeal cancer: Where do we stand?

Nasopharyngeal carcinoma (NPC) is a common head and neck cancer with a poor prognosis. One of the crucial challenges regarding NPC is its pathogenesis. Recent findings highlight the significance of host microbiota in the development of NPC, affected locally by nasopharyngeal microbiota or remotely by oral microbiota. The oral microbiota can migrate to the nasopharyngeal space, thereby impacting the composition of the nasopharyngeal microbiota. Specific bacterial strains have been linked to the development of nasopharyngeal cancer, including Neisseria, Staphylococcus, Leptotrichia, Staphylococcaceae, Granulicatella, Corynebacterium, Fusobacterium, and Prevotella. Several mechanisms have been proposed to elucidate how microbiota dysbiosis contributes to the development of NPC, including triggering tumor-promoting inflammation, reactivating the Epstein-Barr virus (EBV), inducing oxidative stress, weakening the immune system, and worsening tumor hypoxia. In addition, the composition of nasopharyngeal microbiota and the number of tumor-infiltrating microbiota can influence the prognosis and treatment response in patients with NPC. To the best of our knowledge, this is the first review discussing the impacts of the host microbiota on nasopharyngeal cancer pathogenesis, progression, and treatment response.

Epithelial metabolism as a rheostat for intestinal inflammation and malignancy

The gut epithelium protects the host from a potentially hostile environment while allowing nutrient uptake that is vital for the organism. To maintain this delicate task, the gut epithelium has evolved multilayered cellular functions ranging from mucus production to hormone release and orchestration of mucosal immunity. Here, we review the execution of intestinal epithelial metabolism in health and illustrate how perturbation of epithelial metabolism affects experimental gut inflammation and tumorigenesis. We also discuss the impact of environmental factors and host-microbe interactions on epithelial metabolism in the context of inflammatory bowel disease and colorectal cancer. Insights into epithelial metabolism hold promise to unravel mechanisms of organismal health that may be therapeutically exploited in humans in the future.

Molecular mechanisms and therapeutic significance of Tryptophan Metabolism and signaling in cancer

Tryptophan (Trp) metabolism involves three primary pathways: the kynurenine (Kyn) pathway (KP), the 5-hydroxytryptamine (serotonin, 5-HT) pathway, and the indole pathway. Under normal physiological conditions, Trp metabolism plays crucial roles in regulating inflammation, immunity, and neuronal function. Key rate-limiting enzymes such as indoleamine-2,3-dioxygenase (IDO), Trp-2,3-dioxygenase (TDO), and kynurenine monooxygenase (KMO) drive these metabolic processes. Imbalances in Trp metabolism are linked to various cancers and often correlate with poor prognosis and adverse clinical characteristics. Dysregulated Trp metabolism fosters tumor growth and immune evasion primarily by creating an immunosuppressive tumor microenvironment (TME). Activation of the KP results in the production of immunosuppressive metabolites like Kyn, which modulate immune responses and promote oncogenesis mainly through interaction with the aryl hydrocarbon receptor (AHR). Targeting Trp metabolism therapeutically has shown significant potential, especially with the development of small-molecule inhibitors for IDO1, TDO, and other key enzymes. These inhibitors disrupt the immunosuppressive signals within the TME, potentially restoring effective anti-tumor immune responses. Recently, IDO1 inhibitors have been tested in clinical trials, showing the potential to enhance the effects of existing cancer therapies. However, mixed results in later-stage trials underscore the need for a deeper understanding of Trp metabolism and its complex role in cancer. Recent advancements have also explored combining Trp metabolism inhibitors with other treatments, such as immune checkpoint inhibitors, chemotherapy, and radiotherapy, to enhance therapeutic efficacy and overcome resistance mechanisms. This review summarizes the current understanding of Trp metabolism and signaling in cancer, detailing the oncogenic mechanisms and clinical significance of dysregulated Trp metabolism. Additionally, it provides insights into the challenges in developing Trp-targeted therapies and future research directions aimed at optimizing these therapeutic strategies and improving patient outcomes.

Probiotics and the Role of Dietary Substrates in Maintaining the Gut Health: Use of Live Microbes and Their Products for Anticancer Effects against Colorectal Cancer

The gut microbiome is an important and the largest endocrine organ linked to the microbes of the GI tract. The bacterial, viral and fungal communities are key regulators of the health and disease status in a host at hormonal, neurological, immunological, and metabolic levels. The useful microbes can compete with microbes exhibiting pathogenic behavior by maintaining resistance against their colonization, thereby maintaining eubiosis. As diagnostic tools, metagenomic, proteomic and genomic approaches can determine various microbial markers in clinic for early diagnosis of colorectal cancer (CRC). Probiotics are live non-pathogenic microorganisms such as lactic acid bacteria, Bifidobacteria, Firmicutes and Saccharomyces that can help maintain eubiosis when administered in appropriate amounts. In addition, the type of dietary intake contributes substantially to the composition of gut microbiome. The use of probiotics has been found to exert antitumor effects at preclinical levels and promote the antitumor effects of immunotherapeutic drugs at clinical levels. Also, modifying the composition of gut microbiota by Fecal Microbiota Transplantation (FMT), and using live lactic acid producing bacteria such as Lactobacillus, Bifidobacteria and their metabolites (termed postbiotics) can contribute to immunomodulation of the tumor microenvironment. This can lead to tumor-preventive effects at early stages and antitumor effects after diagnosis of CRC. To conclude, probiotics are presumably found to be safe to use in humans and are to be studied further to promote their appliance at clinical levels for management of CRC.

Gut microbiome and serum metabolome alterations associated with lactose intolerance (LI): a case‒control study and paired-sample study based on the American Gut Project (AGP)

Lactose intolerance (LI) is a prevalent condition characterized by gastrointestinal symptoms that arise following lactose consumption. Recent evidence suggests that the gut microbiome may influence lactose levels in the gut. However, there is limited understanding regarding the alterations in microbiota and metabolism between individuals with LI and non-LI. This study conducted a paired-sample investigation utilizing data from the American Gut Project (AGP) and performed metagenomic and untargeted metabolomic analyses in a Chinese cohort to explore the interaction between the gut microbiome and serum metabolites. In addition, fecal microbiota transplantation (FMT) experiments were conducted to further examine the impact of the LI-associated gut microbiome on inflammatory outcomes. We identified 14 microbial genera that significantly differed between LI and controls from AGP data. Using a machine learning approach, group separation was predicted based on seven species and nine metabolites in the Chinese cohort. Notably, increased levels of Escherichia coli in the LI group were negatively correlated with several metabolites, including PC (22:6/0:0), indole, and Lyso PC, while reduced levels of Faecalibacterium prausnitzii and Eubacterium rectale were positively correlated with indole and furazolidone. FMT-LI rats displayed visceral hypersensitivity and an altered gut microbiota composition compared to FMT-HC rats. Metagenomic and metabolomic analyses revealed an enrichment of MAPK signaling in LI, which was confirmed by FMT-LI rats showing higher expression of ERK and RAS, along with increased concentrations of proinflammatory cytokines. This study provides valuable insights into the disrupted microbial and metabolic traits associated with LI, emphasizing potential microbiome-based approaches for its prevention and treatment.

IMPORTANCE

Lactose intolerance (LI) is a prevalent condition characterized by gastrointestinal symptoms after lactose consumption due to a deficiency of lactase. There is limited understanding regarding the microbiota and metabolic alterations between individuals with LI and non-LI. This study represents the first exploration to investigate metagenomic and metabolomic signatures among subjects with lactose intolerance as far as our knowledge. We identified 14 microbial genera in the Western cohort and 7 microbial species, along with 9 circulating metabolites in the Chinese cohort, which significantly differed in LI patients. Metagenomic and metabolomic analyses revealed an enrichment of MAPK signaling in LI patients. This finding was confirmed by FMT-LI rats, exhibiting increased expression of ERK and RAS, along with higher concentrations of pro-inflammatory cytokines. Our study provides insights into the disrupted functional and metabolic traits of the gut microbiome in LI, highlighting potential microbiome-based approaches for preventing and treating LI.

Gasdermin D promotes development of intestinal tumors through regulating IL-1β release and gut microbiota composition

The interplay between gut microbiota and host is crucial for maintaining host health. When this balance is broken, various diseases can arise, including colorectal cancer (CRC). However, the mechanism by which gut microbiota and host interactions mediate CRC development remains unclear. Here, we found that Gasdermin D (GSDMD), an inflammasome effector responsible for forming membrane pores to mediate cell pyroptosis, was upregulated in both human and mouse intestinal tumor samples. GSDMD deficiency significantly suppressed intestinal tumor development in Apcmin/+ mice, a spontaneous CRC mouse model. Apcmin/+Gsdmd-/- mice exhibited reduced IL-1β release in the intestine, and the administration of recombinant mouse IL-1β partially restored intestinal tumor development in Apcmin/+Gsdmd-/- mice. Moreover, 16s rRNA sequencing showed a substantial increase in Lactobacillus abundance in the feces of Apcmin/+Gsdmd-/- mice compared to Apcmin/+ mice. Concurrently, Kynurenine (Kyn), a metabolite derived from host tryptophan (Trp) metabolism, was significantly decreased in the feces of Apcmin/+Gsdmd-/- mice, as shown by metabolite analysis. Additionally, Kyn levels were inversely correlated with Lactobacillus abundance. Furthermore, the administration of exogenous Kyn also promoted intestinal tumor development in Apcmin/+Gsdmd-/- mice. Thus, GSDMD promotes spontaneous CRC development through increasing IL-1β release and Kyn production. Our data suggest an association between GSDMD, gut microbiota, the host Trp/Kyn pathway, and CRC development.

Sex differences and testosterone interfere with the structure of the gut microbiota through the bile acid signaling pathway

Background

The gut microbiome has a significant impact on human wellness, contributing to the emergence and progression of a range of health issues including inflammatory and autoimmune conditions, metabolic disorders, cardiovascular problems, and psychiatric disorders. Notably, clinical observations have revealed that these illnesses can display differences in incidence and presentation between genders. The present study aimed to evaluate whether the composition of gut microbiota is associated with sex-specific differences and to elucidate the mechanism.

Methods

16S-rRNA-sequencing technology, hormone analysis, gut microbiota transplantation, gonadectomy, and hormone treatment were employed to investigate the correlation between the gut microbiome and sex or sex hormones. Meanwhile, genes and proteins involved bile acid signaling pathway were analyzed both in the liver and ileum tissues.

Results

The composition and diversity of the microbiota from the jejunum and feces and the level of sex hormones in the serum differed between the sexes in young and middle-aged Sprague Dawley (SD) rats. However, no similar phenomenon was found in geriatric rats. Interestingly, whether in young, middle-aged, or old rats, the composition of the microbiota and bacterial diversity differed between the jejunum and feces in rats. Gut microbiota transplantation, gonadectomy, and hormone replacement also suggested that hormones, particularly testosterone (T), influenced the composition of the gut microbiota in rats. Meanwhile, the mRNA and protein level of genes involved bile acid signaling pathway (specifically SHP, FXR, CYP7A1, and ASBT) exhibited gender-specific differences, and T may play a significant role in mediating the expression of this pathway.

Conclusion

Sex-specific differences in the structure of the gut microbiota are mediated by T through the bile acid signaling pathway, pointing to potential targets for disease prevention and management techniques by indicating that sex differences and T levels may alter the composition of the gut microbiota via the bile acid signaling pathway.

Exploring the gut microbiome's role in colorectal cancer: diagnostic and prognostic implications

The intricate interplay between the gut microbiome and colorectal cancer (CRC) presents novel avenues for early diagnosis and prognosis, crucial for improving patient outcomes. This comprehensive review synthesizes current findings on the gut microbiome's contribution to CRC pathogenesis, highlighting its potential as a biomarker for non-invasive CRC screening strategies. We explore the mechanisms through which the microbiome influences CRC, including its roles in inflammation, metabolism, and immune response modulation. Furthermore, we assess the viability of microbial signatures as predictive tools for CRC prognosis, offering insights into personalized treatment approaches. Our analysis underscores the necessity for advanced metagenomic studies to elucidate the complex microbiome-CRC nexus, aiming to refine diagnostic accuracy and prognostic assessment in clinical settings. This review propels forward the understanding of the microbiome's diagnostic and prognostic capabilities, paving the way for microbiome-based interventions in CRC management.

Inflammation, Gut Microbiota, and Metabolomic Shifts in Colorectal Cancer: Insights from Human and Mouse Models

Colorectal cancer (CRC) arises from aberrant mutations in colorectal cells, frequently linked to chronic inflammation. This study integrated human gut metagenome analysis with an azoxymethane and dextran sulfate sodium-induced CRC mouse model to investigate the dynamics of inflammation, gut microbiota, and metabolomic profiles throughout tumorigenesis. The analysis of stool metagenome data from 30 healthy individuals and 40 CRC patients disclosed a significant escalation in both gut microbiota diversity and abundance in CRC patients compared to healthy individuals (p < 0.05). Marked structural disparities were identified between the gut microbiota of healthy individuals and those with CRC (p < 0.05), characterized by elevated levels of clostridia and diminished bifidobacteria in CRC patients (p < 0.05). In the mouse model, CRC mice exhibited distinct gut microbiota structures and metabolite signatures at early and advanced tumor stages, with subtle variations noted during the intermediate phase. Additionally, inflammatory marker levels increased progressively during tumor development in CRC mice, in contrast to their stable levels in healthy counterparts. These findings suggest that persistent inflammation might precipitate gut dysbiosis and altered microbial metabolism. Collectively, this study provides insights into the interplay between inflammation, gut microbiota, and metabolite changes during CRC progression, offering potential biomarkers for diagnosis. While further validation with larger cohorts is warranted, the data obtained support the development of CRC prevention and diagnosis strategies.

Influence of the gut microbiota on immune cell interactions and cancer treatment

The tumour microenvironment represents a novel frontier in oncological research. Over the past decade, accumulating evidence has underscored the importance of the tumour microenvironment (TME), including tumour cells, stromal cells, immune cells, and various secreted factors, which collectively influence tumour growth, invasion, and responses to therapeutic agents. Immune cells within the TME are now widely acknowledged to play pivotal roles in tumour development and treatment. While some perspectives have posited that immune cells within the TME facilitate tumour progression and confer resistance to therapeutic interventions, contrasting conclusions also exist. Affirmative and negative conclusions appear to be context dependent, and a unified consensus has yet to be reached. The burgeoning body of research on the relationship between the gut microbiota and tumours in recent years has led to a growing understanding. Most studies have indicated that specific components of the gut microbiota, such as unique bacterial communities or specific secretory factors, play diverse roles in regulating immune cells within the TME, thereby influencing the prognosis and outcomes of cancer treatments. A detailed understanding of these factors could provide novel insights into the TME and cancer therapy. In this study, we aimed to synthesise information on the interactions between the gut microbiota and immune cells within the TME, providing an in-depth exploration of the potential guiding implications for future cancer therapies.

Fusobacterium nucleatum facilitates anti-PD-1 therapy in microsatellite stable colorectal cancer

Microsatellite stable (MSS) colorectal cancers (CRCs) are often resistant to anti-programmed death-1 (PD-1) therapy. Here, we show that a CRC pathogen, Fusobacterium nucleatum (Fn), paradoxically sensitizes MSS CRC to anti-PD-1. Fecal microbiota transplantation (FMT) from patients with Fn-high MSS CRC to germ-free mice bearing MSS CRC confers sensitivity to anti-PD-1 compared to FMT from Fn-low counterparts. Single Fn administration also potentiates anti-PD-1 efficacy in murine allografts and CD34+-humanized mice bearing MSS CRC. Mechanistically, we demonstrate that intratumoral Fn generates abundant butyric acid, which inhibits histone deacetylase (HDAC) 3/8 in CD8+ T cells, inducing Tbx21 promoter H3K27 acetylation and expression. TBX21 transcriptionally represses PD-1, alleviating CD8+ T cell exhaustion and promoting effector function. Supporting this notion, knockout of a butyric acid-producing gene in Fn abolishes its anti-PD-1 boosting effect. In patients with MSS CRC, high intratumoral Fn predicts favorable response to anti-PD-1 therapy, indicating Fn as a potential biomarker of immunotherapy response in MSS CRC.

Multidimensional analysis of the impact of Gemmatimonas, Rhodothermus, and Sutterella on drug and treatment response in colorectal cancer

Background

Colorectal cancer is the third most prevalent cancer across the globe. Despite a diversity of treatment methods, the recurrence and mortality rates of the disease remain high. Recent studies have revealed a close association of the gut microbiota with the occurrence, development, treatment response, and prognosis of colorectal cancer.

Objective

This study aims to integrate transcriptome and microbiome data to identify colorectal cancer subtypes associated with different gut microbiota and evaluate their roles in patient survival prognosis, tumor microenvironment (TME), and drug treatment response.

Methods

An integrated analysis of microbiome data was conducted on samples of colorectal cancer from public databases. Based on this, two tumor subtypes (C1 and C2) closely associated with patient survival prognosis were identified and a risk score model was constructed. The survival status, clinical parameters, immune scores, and other features were analyzed in-depth, and the sensitivity of various potential drugs was examined.

Results

A thorough examination of microbiome information obtained from colorectal cancer patients led to the identification of two primary tumor clusters (C1 and C2), exhibiting notable variations in survival outcomes. Patients with the C1 subtype were closely associated with better prognosis, while those with the C2 subtype had higher gut microbial richness and poorer survival prognosis. A predictive model utilizing the microbiome data was developed to accurately forecast the survival outcome of patients with colorectal cancer. The TME scores provided a biological basis for risk assessment in high-risk (similar to the C2 subtype) patient cohorts. Evaluation of the sensitivity of different subtypes to various potential drugs, indicated the critical importance of personalized treatment. Further analysis showed good potential of the developed risk-scoring model in predicting immune checkpoint functions and treatment response of patients, which may be crucial in guiding the selection of immunotherapy strategies for patients with colorectal cancer.

Conclusion

This study, through a comprehensive analysis of colorectal cancer microbiome, immune microenvironment, and drug sensitivity, enhances the current understanding of the multidimensional interactions of colorectal cancer and provides important clinical indications for improving future treatment strategies. The findings offer a new perspective on improving treatment response and long-term prognosis of patients with CRC through the regulation of microbiota or the utilization of biomarkers provided by it.

Barley polysaccharides inhibit colorectal cancer by two relatively independent pathways

Colorectal cancer is one of the most common types of cancer worldwide that can lead to serious injury and death. Although polysaccharides are widely recognized as having antitumor activity, there has been little research on the role of barley polysaccharides (BP)1 in colorectal cancer. The results of our research suggest that BP (300 mg/kg) had a significant inhibitory effect on colorectal cancer, and this effect was achieved through two pathways. First, BP can directly promote the secretion of protective metabolites like 5-(4-Hydroxyphenyl)-5-phenylimidazolidine-2,4-dione and 2,3-Bis(4-hydroxyphenyl)propionitrile thereby inhibiting the cancer pathways such as ERK, PI3K, WNT, JAK-STAT, Calcium, and Cell cycle cancer pathways to alleviate inflammation. Second, BP also can enrich beneficial intestinal bacteria such as Colidextribacter, Bilophila, and UCG-003 improve the intestinal barrier, promote the production of beneficial metabolites such as 5,8-Epoxy-5,8-dihydro-3-hydroxy-8'-apo-b,y-carotenal and L-Glutamic acid, and thus inhibit cancer pathways such as ERK, PI3K, Nuclear receptor, Cell cycle, Apoptosis and TGF-β. In conclusion, our findings suggest for the first time that BP can alleviate colorectal cancer by two relatively independent pathways: direct action and indirect action via the gut microbiota on both colon tumor cells and microbiota.

KRAS mutation promotes the colonization of Fusobacterium nucleatum in colorectal cancer by down-regulating SERTAD4

This study explores and verifies potential molecular targets through which KRAS mutations regulate the colonization of Fusobacterium nucleatum (FN) in colorectal cancer (CRC). This study combined multiple bioinformatics methods and biological assays. Through The Cancer Genome Atlas, Gene Expression Omnibus, Human Protein Atlas, immunohistochemistry, and co-culture assays, we further confirmed the differential expression of SERTAD4 in CRC. We delved deeper into examining how expression of SERTAD4 is linked with immune cell infiltration and the enrichment of potential pathways. Lastly, through bacterial phenotypic assays, we validated the function of SERTAD4. As a molecule associated with KRAS mutations and FN infection, the expression levels of SERTAD4 were downregulated in CRC. The diagnostic efficacy of SERTAD4 for CRC is not inferior to that of CEA. Low expression of SERTAD4 is associated with poorer overall survival in CRC. Correlation analysis found that increased expression of SERTAD4 is associated with various immune cell infiltrations and immune checkpoint genes. Finally, bacterial adhesion and invasion assays verify that SERTAD4 inhibits the adhesion and invasion abilities of FN in CRC. This study demonstrates that SERTAD4 exerts a protective role in CRC by inhibiting the colonization of FN.

Enterotoxigenic Bacteroides fragilis (ETBF) Enhances Colorectal Cancer Cell Proliferation and Metastasis Through HDAC3/miR-139-3p Pathway

Enterotoxigenic Bacteroides fragilis (ETBF) is believed to promote the malignant process of colorectal cancer (CRC), but the underlying molecular mechanism still needs to be revealed. CRC cells (SW480 and HCT-116) were treated with ETBF strain. Cell proliferation, invasion and, migration were evaluated by cell counting kit 8 assay, EdU assay, colony formation assay, transwell assay, and wound healing assay. Protein expression was analyzed by western blot. MicroRNA (miR)-139-3p and histone deacetylase 3 (HDAC3) expression levels in tissues and cells were determined by qRT-PCR. Xenograft tumor model was conducted to evaluate the effect of miR-139-3p on CRC tumor growth. ETBF treatment could promote CRC cell proliferation, invasion and migration. MiR-139-3p expression was decreased by ETBF, and its overexpression reversed the effect of ETBF on CRC cell progression. HDAC3 negatively regulated miR-139-3p expression, and its overexpression facilitated CRC cell behaviors via reducing miR-139-3p expression. Moreover, HDAC3 expression was increased by ETBF, and its knockdown also abolished ETBF-mediated CRC cell progression. Additionally, miR-139-3p overexpression could reduce CRC tumor growth in vivo. ETBF aggravated CRC proliferation and metastasis via the regulation of HDAC3/miR-139-3p axis. The discovery of ETBF/HDAC3/miR-139-3p axis may provide a new direction for CRC treatment.

What We Know About the Actual Role of Traditional Probiotics in Health and Disease

The complex relationship between probiotics and human health goes beyond their traditional function in gut health, generating considerable interest for their broad potential in disease treatment. This review explores the various functions of probiotics, highlighting their impact on the immune system, their benefits for gut and oral health, their effects on metabolic and neurological disorders, and their emerging potential in cancer therapy. We give significant importance to studying the effects of probiotics on the gut-brain axis, revealing new and non-invasive therapeutic approaches for complex neurological disorders. In addition, we expand the discussion to encompass the impact of probiotics on the gut-liver and gut-lung axes, recognizing their systemic effects and potential in treating respiratory and hepatic conditions. The use of probiotic "cocktails" to improve cancer immunotherapy outcomes indicates a revolutionary approach to oncological treatments. The review explores the specific benefits associated with various strains and the genetic mechanisms that underlie them. This study sets the stage for precision medicine, where probiotic treatments can be tailored to meet the unique needs of each patient. Recent developments in delivery technologies, including microencapsulation and nanotechnology, hold great potential for enhancing the effectiveness and accuracy of probiotic applications in therapeutic settings. This study provides a strong basis for future scientific research and clinical use, promoting the incorporation of probiotics into treatment plans for a wide range of diseases. This expands our understanding of the potential benefits of probiotics in modern medicine.

Review of METTL3 in colorectal cancer: From mechanisms to the therapeutic potential

N6-methyladenosine (m6A), the most abundant modification in mRNAs, affects the fate of the modified RNAs at the post-transcriptional level and participants in various biological and pathological processes. Increasing evidence shows that m6A modification plays a role in the progression of many malignancies, including colorectal cancer (CRC). As the only catalytic subunit in methyltransferase complex, methyltransferase-like 3 (METTL3) is essential to the performance of m6A modification. It has been found that METTL3 is associated with the prognosis of CRC and significantly influences various aspects of CRC, such as cell proliferation, invasion, migration, metastasis, metabolism, tumor microcirculation, tumor microenvironment, and drug resistance. The relationship between METTL3 and gut-microbiota is also involved into the progression of CRC. Furthermore, METTL3 might be a viable target for CRC treatment to prolong survival. In this review, we comprehensively summarize the function of METTL3 in CRC and the underlying molecular mechanisms. We aim to deepen understanding and offer new ideas for diagnostic biomarkers and therapeutic targets for colorectal cancer.

Gut microbiota alterations in colorectal adenoma-carcinoma sequence based on 16S rRNA gene sequencing: A systematic review and meta-analysis

BACKGROUND

Most sporadic colorectal cancers (CRC) develop through the adenoma-carcinoma sequence. While dysbiosis of the intestinal flora contributes to CRC's pathogenesis, precise microbial taxa closely associated with the colorectal adenoma-carcinoma sequence remain elusive. This meta-analysis aimed to summarize the features of intestinal flora in patients with AD and CRC.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science were searched for case-control studies comparing the relative abundance of gut microbiota in the feces of patients with AD, CRC, and healthy controls (HC) from inception to January 2024. The weighted mean difference (WMD) with a 95 % confidence interval (CI) was used to display the results. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the entailed literature. Publication bias was evaluated with the Egger's and Begg's tests.

RESULTS

Eleven studies were included, involving 477 CRC patients, 628 AD patients, and 864 healthy controls. Compared with HC, the patients with AD had a significantly lower Chao 1 index (WMD = -30.17, 95 % CI [-41.10, -19.23], P < 0.001) and Shannon index (WMD = -0.11 95 % CI [-0.18, -0.04], P = 0.002). Compared with AD, the CRC patients had a significantly higher Chao1 index (WMD = 22.09, 95 % CI [7.59, 36.00], P = 0.003) and Shannon index (WMD = 0.08, 95 % CI [0.00, 0.15], P = 0.037). Enterobacteriaceae (WMD = 0.03 95 % CI [0.00,0.05], P = 0.047; WMD = 0.02 95 % CI [0.00,0.04], P = 0.027) significantly increased in the order of Control-AD-CRC, while that of Blautia (WMD = -0.00 95 % CI [-0.01, -0.00], P = 0.001; WMD = -0.00 95 % CI [-0.00, -0.00], P = 0.002) was reduced. Compared with HC, the relative abundance of Proteobacteria (WMD = 0.05 95 % CI [0.03,0.07], P < 0.001), Fusobacteria (WMD = 0.02 95 % CI [0.00,0.03], P = 0.042), Streptococcaceae (WMD = 0.03 95 % CI [0.01,0.05], P = 0.017), Prevotellaceae (WMD = 0.02 95 % CI [0.00,0.04], P = 0.040), and Escherichia-Shigella (WMD = 0.06 95 % CI [0.01, 0.11], P = 0.021) was enriched in the CRC group. The relative abundance of Alistipes (WMD = 0.00 95 % CI [0.00,0.01], P = 0.032) and Streptococcus (WMD = 0.00 95 % CI [0.00,0.00], P = 0.001) was increased in the AD vs HC. The relative abundance of Firmicutes (WMD = -0.07 95 % CI [-0.12, -0.03], P = 0.003), Bifidobacteria (WMD = -0.03 95 % CI [-0.05, -0.01], P = 0.016), and Klebsiella (WMD = -0.01 95 % CI [-0.01, -0.00], P = 0.001) was decreased in the CRC vs HC. Compared with AD, the relative abundance of Firmicutes (WMD = -0.04 95 % CI [-0.07, -0.02], P = 0.002), Peptostreptococcaceae (WMD = -0.03 95 % CI [-0.05, -0.00], P = 0.021), Lachnospiraceae (WMD = -0.04 95 % CI [-0.08,-0.00], P = 0.037), Ruminococcaceae (WMD = -0.06 95 % CI [-0.09,-0.03], P < 0.001), Faecalibacterium (WMD = -0.01 95 % CI [-0.02, -0.01], P = 0.001), and Lachnoclostridium (WMD = -0.02 95 % CI [-0.03, -0.00], P = 0.040) was decreased in the CRC group, while Proteobacteria (WMD = 0.04 95 % CI [0.02,0.05], P < 0.001) was increased.

CONCLUSIONS

The dysbiosis characterized by reduced levels of short-chain fatty acid (SCFA)-producing bacteria, decreased anti-inflammatory bacteria, increased pro-inflammatory bacteria, and an elevation of bacteria with cytotoxic effects damaging to DNA may represent the specific microbial signature of colorectal adenoma/carcinoma. Further research is required to elucidate the mechanisms by which gut dysbiosis leads to the progression from AD to CRC and to explore the potential of specific microbiota markers in clinical treatment and non-invasive screening.

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.

Identification of hsa-miR-193a-5p-SURF4 axis related to the gut microbiota-metabolites- cytokines in lung cancer based on Mendelian randomization study and bioinformatics analysis

BACKGROUND

Lung cancer is a significant disease that affects people's physical and mental health. Currently, the treatment outcomes still do not meet clinical needs, and the causes of the disease are still unclear, therefore further exploration is needed.

METHODS

We analyzed the exposure factors of lung cancer, including gut microbiota, serum metabolites, and cytokines, through Mendelian randomization studies and bioinformatics analysis. We identified common SNPs and performed gene annotation, leading to the discovery of the key gene SURF4, which may affect the onset of lung cancer. We validated the oncogenic function and mechanism of SURF4 through public data analysis using GO and KEGG, and constructed a ceRNA network, revealing the lung cancer oncogenic pathway involving lncRNA/pseudogene-microRNA-SURF4.

RESULTS

We first conducted a Mendelian randomization analysis on 418 gut microbiota, 1400 serum metabolites, and 41 cytokines in relation to lung cancer. We found that 16 gut microbiota, 29 serum metabolites, and 2 cytokines were closely associated with lung cancer. Further comparison of all differential SNPs revealed that rs550057 on chromosome 9 was a common SNP among these three exposure factors, indicating its crucial role in lung cancer formation. Through gene functional annotation using R language, we found that the expression of 15 genes, including SURF4, was influenced by rs550057. By querying these 15 genes from public databases for their differential expression and prognosis in lung cancer, we found significant differences in SURF4, MED22, and RPL7A. Furthermore, by querying the expression and correlation coefficients of upstream microRNAs of these three genes through the starBase website, we found that hsa-miR-193a-5p-SURF4 had the most significant effect on lung cancer. Through GO and KEGG analysis of SURF4-related genes, we identified the molecular pathways associated metabolic synthesis and microbial infection related to the promotion of lung cancer by SURF4. This validated the results of the previous Mendelian randomization study. Furthermore, we constructed a ceRNA network for SURF4 and identified two upstream differentially expressed pseudogenes and nine lncRNAs, confirming the functionality of the pseudogene/lncRNA-microRNA-SUFR4 pathway.

CONCLUSIONS

In summary, we have elucidated the regulatory role of the pseudogene/lncRNA-microRNA-SUFR4 pathway in the progression of lung cancer, combining the research hotspots of gut microbiota-serum metabolites-cytokines. We have also confirmed the pathway and mechanism through SURF4 and its related genes promoting lung cancer formation. This may provide effective therapeutic methods for lung cancer and serve as a potential prognostic marker.

Microbiota and beneficial metabolites in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death worldwide. In recent years, the impact of the gut microbiota on the development of CRC has become clear. The gut microbiota is the community of microorganisms living in the gut symbiotic relationship with the host. These microorganisms contribute to the development of CRC through various mechanisms that are not yet fully understood. Increasing scientific evidence suggests that metabolites produced by the gut microbiota may influence CRC development by exerting protective and deleterious effects. This article reviews the metabolites produced by the gut microbiota, which are derived from the intake of complex carbohydrates, proteins, dairy products, and phytochemicals from plant foods and are associated with a reduced risk of CRC. These metabolites include short-chain fatty acids (SCFAs), indole and its derivatives, conjugated linoleic acid (CLA) and polyphenols. Each metabolite, its association with CRC risk, the possible mechanisms by which they exert anti-tumour functions and their relationship with the gut microbiota are described. In addition, other gut microbiota-derived metabolites that are gaining importance for their role as CRC suppressors are included.

Fusobacterium nucleatum extracellular vesicles are enriched in colorectal cancer and facilitate bacterial adhesion

Fusobacterium nucleatum in colorectal cancer (CRC) tissue is implicated at multiple stages of the disease, while the mechanisms underlying bacterial translocation and colonization remain incompletely understood. Herein, we investigated whether extracellular vesicles derived from F. nucleatum (FnEVs) have impacts on bacterial colonization. In mice with colitis-related CRC, a notable enrichment of FnEVs was observed, leading to a significant increase in intratumor colonization by F. nucleatum and accelerated progression of CRC. The enrichment of FnEVs in clinical CRC tissues was demonstrated. Subsequently, we revealed that FnEVs undergo membrane fusion with CRC cells, leading to the transfer and retention of FomA on recipient cell surfaces. Given its ability to facilitate F. nucleatum autoaggregation through interaction with FN1441, the presence of FomA on CRC cell surfaces presents a target for bacterial adhesion. Collectively, the findings unveil a mechanism used by EVs to prepare a niche conducive for bacterial colonization in distal organs.