Fusobacterium nucleatum promotes chemoresistance to 5-fluorouracil by upregulation of BIRC3 expression in colorectal cancer

Oral Fusobacterium nucleatum exacerbates ulcerative colitis via the oral-gut axis: mechanisms and therapeutic implications

Background

Fusobacterium nucleatum (F. nucleatum) is an anaerobic bacterium known for its association with periodontal disease and oral infections. It has been implicated in the development of gastrointestinal diseases such as inflammatory bowel disease and colorectal cancer. Ulcerative colitis (UC), which is characterized by chronic inflammation of the colon, is a condition of unknown etiology with a rising incidence rate, significantly affecting the quality of life for patients. The increased intestinal permeability during UC may facilitate the adherence or invasion of F. nucleatum into the damaged intestinal barrier, leading to exacerbated inflammation.

Methods

This article introduces the concept of the oral-gut axis, reviewing existing literature to analyze the role of F. nucleatum in the pathogenesis of UC and exploring its potential pathogenic mechanisms. It also summarizes the latest advances in treating patients with UC who have F. nucleatum and looks forward to prospective therapeutic strategies and the translational prospects of F. nucleatum within the oral-gut axis.

Results

F. nucleatum may be a key player in the pathogenesis of UC, likely due to its invasiveness during periods of increased intestinal permeability. The paper also discusses innovative approaches for the prevention and management of UC exacerbated by F. nucleatum, paving the way for more effective treatment of UC.

Conclusion

The review offers new insights into the complex relationship between the oral microbiome and intestinal diseases, enhancing our understanding of their dynamic interactions. There is a paucity of literature on therapeutic approaches, indicating a need for further clinical research.

Fusobacterium nucleatum modulates the Wnt/β-catenin pathway in colorectal cancer development

The Wnt/β-catenin signalling pathway normally maintains cellular and tissue homeostasis by regulating cellular differentiation and survival in a controlled manner. An aberrantly regulated Wnt/β-catenin signalling pathway can transform into an oncogenic pathway, which is associated with Colorectal cancer (CRC) as well as other cancers. CRC is one of the most frequently occurring gastrointestinal cancers worldwide. In CRC tissues, deregulation of Wnt/β-catenin pathway is observed, which indicates that this oncogenic pathway directly promotes CRC malignancy, cell migration, angiogenesis, chemoresistance, as well as shorter lifespan of a patient. Growing evidence suggests that human commensal microbes have a strong association with carcinogenesis, particularly the prevalence and high enrichment of Fusobacterium nucleatum in CRC progression. The Wnt/β-catenin pathway is one of the targeted pathways by F. nucleatum in CRC, where Fusobacterium adhesin attaches to E-cadherin to initiate infection. Also, Wnt/β-catenin pathway can be a potential target for the treatment of both CRC and F. nucleatum-positive CRC. Here, we discuss the underlying mechanisms of F. nucleatum-positive CRC development through modulation of Wnt/β-catenin signalling and its possibility for the application in targeted therapy of F. nucleatum-positive CRC.

Characterization of diet-linked amino acid pool influence on Fusobacterium spp. growth and metabolism

The genus Fusobacterium contains multiple proteolytic opportunistic pathogens that have been increasingly linked to colorectal cancer (CRC). "Oncomicrobes" such as these fusobacterial species within the gut microbiota may contribute to CRC onset and/or progression. Protein-rich diets may both directly increase CRC risk and enrich for proteolytic oncomicrobes, including Fusobacterium spp. Individual food substrates vary in amino acid content, and released amino acid content that is not absorbed in the small intestine may influence the growth of colonic proteolytic fermenters. Fusobacteria such as Fusobacterium spp. are known to preferentially metabolize certain amino acids. As such, some foods may better support the growth of these species within the colonic environment than others. To explore this, in this study, we created free amino acid pools (FAAPs) to represent proportions of amino acids in major proteins of three common dietary protein sources (soy, beef, and bovine milk). Growth curves were generated for 39 Fusobacterium spp. strains cultured in a dilute medium supplemented with each of the three FAAPs. Thereafter, amino acid use by 31 of the 39 Fusobacterium spp. strains in each FAAP treatment was assessed. FAAP supplementation increased growth metrics of all Fusobacterium spp. strains tested; however, the strains varied greatly in terms of the FAAP(s) generating the greatest increase in growth. Furthermore, the amino acid utilization strategy was highly variable between strains of Fusobacterium spp. Neither growth metrics nor amino acid utilization could be explained by species classification of Fusobacterium spp. strains. This report expands upon the previous knowledge of fusobacterial amino acid metabolism and indicates that proteolytic oncomicrobial activity should be assessed in the context of available protein sources.IMPORTANCEFusobacterium spp. including F. animalis, F. nucleatum, F. vincentii, and F. polymorphum are common oral commensals with emerging importance in diseases across multiple body sites, including CRC. CRC lesions associated with fusobacteria tend to result in poorer prognosis and increased disease recurrence. While Fusobacterium spp. are thought to colonize after tumorigenesis, little is known about the factors that facilitate this colonization. Protein-rich diets yielding readily metabolized free amino acids within the colon may promote the growth of proteolytic fermenters such as fusobacteria. Here, we show that variable concentrations of free amino acids within pools that represent different dietary protein sources differentially influence fusobacterial growth, including CRC-relevant strains of Fusobacterium spp. This work highlights the high degree of variation in fusobacterial amino acid utilization patterns and suggests differing proportions of dietary amino acids that reach the colon could influence fusobacterial growth.

BIRC3 RNA Editing Modulates Lipopolysaccharide-Induced Liver Inflammation: Potential Implications for Animal Health

Animals and humans are frequently infected by bacteria or exposed to bacterial derivatives in contaminated food, drinking water, or air, which significantly impacts their health. Among these bacterial sources, LPS (lipopolysaccharide) is the primary culprit. While it is widely known that LPS can cause liver inflammation and damage in animals, few studies have investigated this mechanism from the perspective of RNA editing. In this study, we administered LPS to mice via gavage to induce a liver injury model. We then used RNA editing omics approaches (RE-seq) to analyze RNA editing events potentially leading to liver inflammation following LPS administration, aiming to reveal the crucial role of RNA editing in LPS-induced processes. At the RNA editing level, we observed significant differences between the LPS group and the control (CON) group. Specifically, we identified 354 differentially edited genes, with 192 upregulated and 162 downregulated. These differentially edited genes were significantly enriched in pathways related to apoptosis, mTOR signaling, oxidative stress, and Nf-Kappa B signaling. By further integrating gene expression profiles and using a nine-quadrant analysis, we identified an important gene, Birc3, which showed significantly higher editing and expression levels in the LPS group. This gene is directly linked to liver inflammation and damage. The RNA editing of Birc3 represents a significant potential mechanism underlying LPS-induced liver damage, providing a novel approach for addressing animal and human health issues.

Exploring the Impact of Chemotherapy on the Emergence of Antibiotic Resistance in the Gut Microbiota of Colorectal Cancer Patients

With nearly half of colorectal cancer (CRC) patients diagnosed at advanced stages where surgery alone is insufficient, chemotherapy remains a cornerstone for this cancer treatment. To prevent infections and improve outcomes, antibiotics are often co-administered. However, chemotherapeutic interactions with the gut microbiota cause significant non-selective toxicity, affecting not only tumor and normal epithelial cells but also the gut microbiota. This toxicity triggers the bacterial SOS response and loss of microbial diversity, leading to bacterial mutations and dysbiosis. Consequently, pathogenic overgrowth and systemic infections increase, necessitating broad-spectrum antibiotics intervention. This review underscores how prolonged antibiotic use during chemotherapy, combined with chemotherapy-induced bacterial mutations, creates selective pressures that drive de novo antimicrobial resistance (AMR), allowing resistant bacteria to dominate the gut. This compromises the treatment efficacy and elevates the mortality risk. Restoring gut microbial diversity may mitigate chemotherapy-induced toxicity and improve therapeutic outcomes, and emerging strategies, such as fecal microbiota transplantation (FMT), probiotics, and prebiotics, show considerable promise. Given the global threat posed by antibiotic resistance to cancer treatment, prioritizing antimicrobial stewardship is essential for optimizing antibiotic use and preventing resistance in CRC patients undergoing chemotherapy. Future research should aim to minimize chemotherapy's impact on the gut microbiota and develop targeted interventions to restore microbial diversity affected during chemotherapy.

Interspecies interactions mediated by arginine metabolism enhance the stress tolerance of Fusobacterium nucleatum against Bifidobacterium animalis

Colorectal cancer (CRC) is a common cancer accompanied by microbiome dysbiosis. Exploration of probiotics against oncogenic microorganisms is promising for CRC treatment. Here, differential microorganisms between CRC and healthy control were analyzed. Antibacterial experiments, whole-genome sequencing, and metabolic network reconstruction were combined to reveal the anti-Fusobacterium nucleatum mechanism, which was verified by co-culture assay and mendelian randomization analysis. Sequencing results showed that F. nucleatum was enriched in CRC, yet Bifidobacterium animalis decreased gradually from healthy to CRC. Additionally, F. nucleatum could be inhibited by B. animalis. Whole-genome sequencing of B. animalis showed high phylogenetic similarity with known probiotic strains and highlighted its functions for amino acid and carbohydrate metabolism. Metabolic network reconstruction demonstrated that cross-feeding and specific metabolites (acidic molecules, arginine) had a great influence on the coexistence relationship. Finally, the arginine supplement enhanced the competitive ability of F. nucleatum against B. animalis, and the mendelian randomization and metagenomic sequencing analysis confirmed the positive relationship among F. nucleatum, arginine metabolism, and CRC. Thus, whole-genome sequencing and metabolic network reconstruction are valuable for probiotic mining and patient dietary guidance.IMPORTANCEUsing probiotics to inhibit oncogenic microorganisms (Fusobacterium nucleatum) is promising for colorectal cancer (CRC) treatment. In this study, whole-genome sequencing and metabolic network reconstruction were combined to reveal the anti-F. nucleatum mechanism of Bifidobacterium animalis, which was verified by co-culture assay and mendelian randomization analysis. The result indicated that the arginine supplement enhanced the competitive ability of F. nucleatum, which may be harmful to F. nucleatum-infected CRC patients. B. animalis is a potential probiotic to relieve this dilemma. Thus, using in silico simulation methods based on flux balance analysis, such as genome-scale metabolic reconstruction, provides valuable insights for probiotic mining and dietary guidance for cancer patients.

Gut microbiota derived DCA enhances FOLFOX efficacy via Ugt1a6b mediated enterohepatic circulation in colon cancer

FOLFOX (5-Fluorouracil, Calcium Folinate combined with Oxaliplatin) is a preferred chemotherapy regimen for colon cancer, but its limited efficacy remains a major challenge, significantly impairs patient outcomes. There is an urgent need to identify strategies to improve its therapeutic effectiveness. Our previous studies have suggested that gut microbiota-derived bile acids may be involved in the anticancer effect of FOLFOX in vitro, however, the underlying mechanism remains unclear. In this study, we investigated the role of bile acids in modulating FOLFOX efficacy and the related mechanisms. We first demonstrated that bile acids depletion (cholestyramine treatment) enhanced FOLFOX efficacy in an orthotopic colon cancer mouse model, suggesting that bile acids play a key role in FOLFOX's therapeutic effects. Further, based on the system screen of 15 bile acids on FOLFOX efficacy via MTT, colony formation and flow cytometry assay, Deoxycholic Acid (DCA) and Glycodeoxycholic Acid (GDCA) were annotated as potential modulators of FOLFOX efficacy. Among these, DCA was further validated to significantly enhance FOLFOX's anti-colon cancer effects in vivo. Transcriptomic analysis and subsequent biological experiments revealed that DCA enhanced FOLFOX efficacy via Ugt1a6b. In conclusion, our findings establish that gut microbiota-derived DCA enhances the efficacy of FOLFOX potentially via Ugt1a6b mediated enterohepatic circulation, providing novel insights into a synergistic therapeutic strategy for improving colon cancer treatment.

Intratumoral microbiome: implications for immune modulation and innovative therapeutic strategies in cancer

Recent advancements have revealed the presence of a microbiome within tumor tissues, underscoring the crucial role of the tumor microbiome in the tumor ecosystem. This review delves into the characteristics of the intratumoral microbiome, underscoring its dual role in modulating immune responses and its potential to both suppress and promote tumor growth. We examine state-of-the-art techniques for detecting and analyzing intratumoral bacteria, with a particular focus on their interactions with the immune system and the resulting implications for cancer prognosis and treatment. By elucidating the intricate crosstalk between the intratumoral microbiome and the host immune system, we aim to uncover novel therapeutic strategies that enhance the efficacy of cancer treatments. Additionally, this review addresses the existing challenges and future prospects within this burgeoning field, advocating for the integration of microbiome research into comprehensive cancer therapy frameworks.

Tumor microbiome: roles in tumor initiation, progression, and therapy

Over the past few years, the tumor microbiome is increasingly recognized for its multifaceted involvement in cancer initiation, progression, and metastasis. With the application of 16S ribosomal ribonucleic acid (16S rRNA) sequencing, the intratumoral microbiome, also referred to as tumor-intrinsic or tumor-resident microbiome, has also been found to play a significant role in the tumor microenvironment (TME). Understanding their complex functions is critical for identifying new therapeutic avenues and improving treatment outcomes. This review first summarizes the origins and composition of these microbial communities, emphasizing their adapted diversity across a diverse range of tumor types and stages. Moreover, we outline the general mechanisms by which specific microbes induce tumor initiation, including the activation of carcinogenic pathways, deoxyribonucleic acid (DNA) damage, epigenetic modifications, and chronic inflammation. We further propose the tumor microbiome may evade immunity and promote angiogenesis to support tumor progression, while uncovering specific microbial influences on each step of the metastatic cascade, such as invasion, circulation, and seeding in secondary sites. Additionally, tumor microbiome is closely associated with drug resistance and influences therapeutic efficacy by modulating immune responses, drug metabolism, and apoptotic pathways. Furthermore, we explore innovative microbe-based therapeutic strategies, such as engineered bacteria, oncolytic virotherapy, and other modalities aimed at enhancing immunotherapeutic efficacy, paving the way for microbiome-centered cancer treatment frameworks.

Bacteria-tumor symbiosis destructible novel nanocatalysis drug delivery systems for effective tumor therapy

Colorectal cancer (CRC) is a significant threat to human health. The dynamic equilibrium between probiotics and pathogenic bacteria within the gut microbiota is crucial in mitigating the risk of CRC. An overgrowth of harmful microorganisms in the gastrointestinal tract can result in an excessive accumulation of bacterial toxins and carcinogenic metabolites, thereby disrupting the delicate balance of the microbiota. This disruption may lead to alterations in microbial composition, impairment of mucosal barrier function, potential promotion of abnormal cell proliferation, and ultimately contribute to the progression of CRC. Recently, research has indicated that intestinal presence of Fusobacterium nucleatum (Fn) significantly influences the onset, progression, and metastasis of CRC. Consequently, disrupting the interaction between CRC cells and Fn presents a promising strategy against CRC. Nanomaterials have been extensively utilized in cancer therapy and bacterial infection control, demonstrating substantial potential in treating bacteria-associated tumors. This review begins by elucidating the mechanisms of gut microbiota and the occurrence and progression of CRC, with a particular emphasis on clarifying the intricate relationship between Fn and CRC. Subsequently, we highlight strategies that utilize nanomaterials to disrupt the association between Fn and CRC. Overall, this review offers valuable insight and guidance for leveraging nanomaterials in CRC therapy.

Interactions between the tumor microbiota and breast cancer

Breast cancer is the most common malignancy in women worldwide. Changes in the microbiota and their metabolites affect the occurrence and development of breast cancer; however, the specific mechanisms are not clear. Gut microbes and their metabolites influence the development of breast cancer by regulating the tumor immune response, estrogen metabolism, chemotherapy, and immunotherapy effects. It was previously thought that there were no microorganisms in breast tissue, but it is now thought that there are microorganisms in breast cancer that can affect the outcome of the disease. This review builds on existing research to comprehensively analyze the role of gut and intratumoral microbiota and their metabolites in the development and metastasis of breast cancer. We also explore the potential function of the microbiota as biomarkers for prognosis and therapeutic response, highlighting the need for further research to clarify the causal relationship between the microbiota and breast cancer. We hope to provide new ideas and directions for the development of new methods for breast cancer treatment.

Unraveling the Role of Fusobacterium nucleatum in Colorectal Cancer: Molecular Mechanisms and Pathogenic Insights

Fusobacterium nucleatum, a gram-negative anaerobic bacterium, has emerged as a significant player in colorectal cancer (CRC) pathogenesis. The bacterium causes a persistent inflammatory reaction in the colorectal mucosa by stimulating the release of pro-inflammatory cytokines like IL-1β, IL-6, and TNF-α, creating an environment conducive to cancer progression. F. nucleatum binds to and penetrates epithelial cells through adhesins such as FadA, impairing cell junctions and encouraging epithelial-to-mesenchymal transition (EMT), which is associated with cancer advancement. Additionally, the bacterium modulates the host immune system, suppressing immune cell activity and creating conditions favorable for tumor growth. Its interactions with the gut microbiome contribute to dysbiosis, further influencing carcinogenic pathways. Evidence indicates that F. nucleatum can inflict DNA damage either directly via reactive oxygen species or indirectly by creating a pro-inflammatory environment. Additionally, it triggers oncogenic pathways, especially the Wnt/β-catenin signaling pathway, which promotes tumor cell growth and longevity. Moreover, F. nucleatum alters the tumor microenvironment, impacting cancer cell behavior, metastasis, and therapeutic responses. The purpose of this review is to elucidate the molecular mechanisms by which F. nucleatum contributes to CRC. Understanding these mechanisms is crucial for the development of targeted therapies and diagnostic strategies for CRC associated with F. nucleatum.

Tissue-Resident Memory T Cells in Tumor Immunity and Immunotherapy of Digestive System Tumors

Background: Tissue-resident memory T (TRM) cells possess unique abilities to migrate, establish themselves in tissues, and monitor peripheral tissues without circulating. They are crucial in providing long-lasting and local immune protection against surface infections. TRMs demonstrate distinct phenotypic and functional characteristics compared to central memory T (Tcm) cells and effector memory T (Tem) cells.Methods: We reviewed a large number of literature to explore the physiological and functional roles of tissue-resident memory T cells, as well as the link between TRM cells and the development and prognosis of digestive tract tumors. We also investigated the association between TRM cells, intestinal flora, and metabolites.Results: Recent studies have implicated TRMs in the immune response against tumors, making them a potential target for cancer therapy. However, research specifically focused on gastrointestinal tumors is limited.Conclusion: This review aims to compile and assess the most recent data on the role of TRM cells in gastrointestinal tumor immunity. Additionally, it explores recent advancements in immunotherapy and investigates how TRMs may influence intestinal flora and metabolites.

Oral microbiota: the overlooked catalyst in cancer initiation and progression

The advancement of high-throughput sequencing technology in recent decades has led to a greater understanding of the components of the oral microbiota, providing a solid foundation for extensive research in this field. The oral microbiota plays an important role in an individual's overall health. It has been shown to be significantly correlated with chronic human diseases, including diabetes, rheumatoid arthritis, cardiovascular disease, periodontal disease, and Alzheimer's disease. Furthermore, tumor occurrence and development are closely related to the oral microbiome. Specific bacteria, such as Fusobacterium nucleatum (F. nucleatum), Porphyromonas gingivalis (P. gingivalis), Streptococcus, Streptomyces, Prevotella, and Fibrophagy gingivalis, play critical roles in cancer development. The oral microbiota has various oncogenic mechanisms, including bacterial inflammation, immunological suppression, tumor growth mediated by bacterial toxins, antiapoptotic activity, and carcinogenic effects. This paper reviews the role of the oral microbiota in the occurrence and progression of cancer and systematically elucidates the molecular mechanisms by which dysbiosis influences tumorigenesis and tumor progression. This information can provide a theoretical basis for exploring cancer treatment strategies and offer new insights for cancer prevention.

Unveiling the Interplay Between the Human Microbiome and Gastric Cancer: A Review of the Complex Relationships and Therapeutic Avenues

The human microbiota plays a crucial role in maintaining overall health and well-being. The gut microbiota has been implicated in developing and progressing various diseases, including cancer. This review highlights the related mechanisms and the compositions that influence cancer pathogenesis with a highlight on gastric cancer. We provide a comprehensive overview of the mechanisms by which the microbiome influences cancer development, progression, and response to treatment, with a focus on identifying potential biomarkers for early detection, prevention strategies, and novel therapeutic interventions that leverage microbiome modulation. This comprehensive review can guide future research and clinical practices in understanding and harnessing the microbiome to optimize gastric cancer therapies.

The Oral Microbiome and Cancer

There is growing evidence suggesting a strong association between members of the oral microbiota and various types of cancer, including oral cancer, colorectal cancer, esophageal squamous cell carcinoma, and pancreatic cancer. Periodontal diseases closely associated with pathogenic bacteria in the oral cavity have been shown to be correlated with the occurrence and development of cancers. Among the periodontal disease-associated bacteria in the oral cavity, two prominent oral pathogens, Porphyromonas gingivalis and Fusobacterium nucleatum, have been found to promote tumor cell proliferation, invasion, and migration, as well as to inhibit immune cell function, thereby facilitating tumor progression. The presence of other oral pathogenic bacteria, such as Treponema denticola, Tannerella forsythia, Parvimonas micra, and Aggregatibacter actinomycetemcomitans, has also been found to be associated with cancer worsening. Oral commensal bacteria play a crucial role in maintaining the normal oral homeostasis. However, the relationship between oral commensal bacteria and the occurrence and development of cancers remains controversial. Some studies suggest an increase in oral commensal bacteria during tumor development, while others suggest an association of certain commensal bacteria with lower tumor risk. The microbiota can significantly alter responses and toxicity to various forms of cancer treatment through interactions with the human body, thereby influencing disease progression. In this chapter, we provide a concise overview of current understanding of the role of the oral microbiota in cancer.

Crosstalk between gut microbiota and cancer chemotherapy: current status and trends

BACKGROUND

Chemotherapy is crucial in the management of tumors, but challenges such as chemoresistance and adverse reactions frequently lead to therapeutic delays or even premature cessation. A growing body of research underscores a profound connection between the gut microbiota (GM) and cancer chemotherapy (CC). This paper aims to pinpoint highly influential publications and monitor the current landscape and evolving trends within the realm of GM/CC research.

METHODS

On October 1st, 2024, a comprehensive search for GM/CC publications spanning the past 20 years from 2004 to 2023 was conducted utilizing the Web of Science Core Collection (WoSCC). The scope encompassed both articles and reviews, and the data was subsequently extracted. To gain insights into the evolution and dynamics of this research field, we employed bibliometric analysis tools such as the Bibliometrix R package, VOSviewer, and Microsoft Excel to visualize and analyze various dimensions, including prominent journals, leading authors, esteemed institutions, contributing countries/regions, highly cited papers, and frequently occurring keywords.

RESULTS

A total of 888 papers were obtained. The number of publications about GM/CC studies has increased gradually. China and the United States published the largest number of papers. The INSERM was in the leading position in publishers. The most productive authors were Zitvogel L from France. Cancers had the largest number of papers. Citation analysis explained the historical evolution and breakthroughs in GM/CC research. Highly cited papers and common keywords illustrated the status and trends of GM/CC research. Four clusters were identified, and the hot topics included the role of the GM in the efficacy and toxicity of CC, the targeting of the GM to improve the outcome of CC, the mechanism by which the GM affects CC, and the correlation of the GM with carcinogenesis and cancer therapy. Metabolism, GM-derived metabolites, tumor microenvironment, immunity, intestinal barrier, tumor microbiota and Fusobacterium nucleatum may become the new hotspots and trends of GM/CC research.

CONCLUSION

This study analyzed global publications and bibliometric characteristics of the links between GM and CC, identified highly cited papers in GM/CC, provided insight into the status, hotspots, and trends of global GM/CC research, and showed that the GM can be used to predict the efficacy and toxicity of CC and modifying the GM can improve the outcomes of chemotherapeutics, which may inform clinical researchers of future directions.

The emerging role of Fusobacteria in carcinogenesis

The Fusobacterium genus comprises Gram-negative, obligate anaerobic bacteria that typically reside in the periodontium of the oral cavity, gastrointestinal tract, and female genital tract. The association of Fusobacterial spp. with colorectal tumours is widely accepted, with further evidence that this pathogen may also be implicated in the development of other malignancies. Fusobacterial spp. influence malignant cell behaviours and the tumour microenvironment in various ways, which can be related to the multiple surface adhesins expressed. These adhesins include Fap2 (fibroblast-activated protein 2), CpbF (CEACAM binding protein of Fusobacteria), FadA (Fusobacterium adhesin A) and FomA (Fusobacterial outer membrane protein A). This review outlines the influence of Fusobacteria in promoting cancer initiation and progression, impacts of therapeutic outcomes and discusses potential therapeutic interventions where appropriate.

Effect of Chemotherapy on Fusobacterium nucleatum Abundance in Colorectal Cancer Patients: A Study on Relapsing Patients

An intricate relationship exists, and interactions occur between the gut microbiota and colorectal cancer (CRC). Recent studies have indicated that inflammatory reactions stimulated by Fusobacterium nucleatum (Fn) lead to the development of CRC. Radical surgery combined with adjuvant chemotherapy is the primary treatment approach for most CRC patients. This study was designed to evaluate the abundance of Fn as part of the gut microbiota in patients with CRC compared to healthy individuals and to assess the effect of the gut microbiota Fn on patients undergoing adjuvant chemotherapy and those experiencing CRC relapse. There were 201 participants, comprising 50 healthy controls and 151 CRC patients. Stool samples were collected from three CRC groups (postoperatively, chemotherapy and relapse), and the fourth was the healthy control group. The amount of Fn in each sample was analyzed using quantitative loop-mediated isothermal amplification-phenol red (QLAMP-PhR), a novel biomolecular method that targets regions encoding the specific Fn FadA gene. Compared with healthy control stool samples, the Fn levels were significantly elevated in all CRC patient groups (P < 0.001), and it was significantly more frequent in the CRC relapse patients (group C) (P < 0.001). In addition, Fn abundance increased significantly in the distal colon compared to the proximal colon (P < 0.001). Both CRC relapse and chemotherapy exert significant reciprocal effects on the gut microbiota Fn of CRC patients. Microbiota-based intervention may be beneficial for patients during postoperative care, especially in CRC relapsing cases. Registration: This study of the clinical trial has been registered in the ISRCTN registry with study registration number ISRCTN53358464. https://www.isrctn.com/ISRCTN53358464.

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1007/s12088-024-01279-6.

Targeting the gut and tumor microbiome in cancer treatment resistance

Therapy resistance represents a significant challenge in oncology, occurring in various therapeutic approaches. Recently, animal models and an increasing set of clinical trials highlight the crucial impact of the gut and tumor microbiome on treatment response. The intestinal microbiome contributes to cancer initiation, progression, and formation of distant metastasis. In addition, tumor-associated microbiota is considered a critical player in influencing tumor microenvironments and regulating local immune processes. Intriguingly, numerous studies have successfully identified pathogens within the gut and tumor microbiome that might be linked to a poor response to different therapeutic modalities. The unfavorable microbial composition with the presence of specific microbes participates in cancer resistance and progression via several mechanisms, including upregulation of oncogenic pathways, macrophage polarization reprogramming, metabolism of chemotherapeutic compounds, autophagy pathway modulation, enhanced DNA damage repair, inactivation of a proapoptotic cascade, and bacterial secretion of extracellular vesicles, promoting the processes in the metastatic cascade. Targeted elimination of specific intratumoral bacteria appears to enhance treatment response. However, broad-spectrum antibiotic pretreatment is mostly connected to reduced efficacy due to gut dysbiosis and lower diversity. Mounting evidence supports the potential of microbiota modulation by probiotics and fecal microbiota transplantation to improve intestinal dysbiosis and increase microbial diversity, leading to enhanced treatment efficacy while mitigating adverse effects. In this context, further research concerning the identification of clinically relevant microbiome signatures followed by microbiota-targeted strategies presents a promising approach to overcoming immunotherapy and chemotherapy resistance in refractory patients, improving their outcomes.

Does Fusobacterium in Colorectal Cancer Sites Originate From the Oral Cavity? A Pilot Study

OBJECTIVES

Fusobacterium can contribute to oral diseases, but also pose as a systemic risk factor. This genus, and especially F. nucleatum, can be found in colorectal cancer (CRC) tissue and is involved in multiple aspects of this type of cancer. Previous studies indicated a possible oral origin of these bacteria; however, stronger evidence is needed to reach a definitive conclusion. This pilot study aimed to establish a method to successfully compare, at the strain level, fusobacteria from the oral cavity and CRC resection material for future cohort studies of CRC patients.

MATERIAL AND METHODS

In a first cohort of eight periodontitis patients, gingival crevicular fluid and saliva were collected. Fusobacterium was isolated on two different media. In a second cohort, saliva and CRC resection material were collected from ten CRC patients. These samples were used for screening of Fusobacterium with culturing, 16S rRNA gene profiling and a PCR-based approach.

RESULTS

In the first cohort, different Fusobacterium species were identified in GCF and saliva samples. However, as the total yield of Fusobacterium seemed slightly higher in saliva samples, it was therefore preferred for subsequent sample collection. Thus, in the second cohort, patient-matched saliva and CRC resection material were screened for Fusobacterium and this showed that nine patients were culture-positive in the saliva samples; however, no Fusobacterium could be isolated from the resection material. On the other hand, 16S rRNA gene profiling of the resection material indicated that eight CRC patients were positive for Fusobacterium. All eight of these patients carried Fusobacterium in their saliva, indicated by both marker gene PCR and culture-based screening.

CONCLUSIONS

These pilot results are compatible with data from previous studies, indicating a possible link between oral and CRC-associated Fusobacterium, and a more in-depth analysis of specific strains and their characteristics in a larger cohort is justified.

TRIAL REGISTRATION

The protocol was registered at clinicaltrials.gov (NCT05945082).

Efficacy of probiotics or synbiotics supplementation on chemotherapy-induced complications and gut microbiota dysbiosis in gastrointestinal cancer: a systematic review and meta-analysis

This study aimed to systematically review the clinical efficacy of probiotics or synbiotics supplementation in the treatment of chemotherapy-induced complications and gut microbiota dysbiosis in patients with gastrointestinal cancer. A literature search was performed systematically using PubMed, Embase, Cochrane, Web of Science, Wanfang Data, and CNKI for randomized controlled trials of probiotics or synthetic supplementation on chemotherapy-induced complications and gut microbiota dysbiosis in gastrointestinal cancer up to December 2023. The outcome measures included chemotherapy-related complications and the the incidence of gut microbiotas. Fifteen studies were finally eligible for meta-analysis, involving 1356 patients. Meta-analysis results showed that the the incidence rates of chemotherapy-related complications such as nausea and vomiting [RR = 0.61, 95% CI (0.46,0.82), P = 0.0008] and diarrhea [RR = 0.47, 95% CI (0.32,0.68), P < 0.001] were significantly reduced after probiotic intervention. The number of intestinal flora changed significantly after intervention, such as bifidobacterium [SMD = 1.33, 95% CI (0.52,2.31), P = 0.001], Escherichia coli [SMD = -0.82, 95% CI (-1.26, -0.38), P = 0.0003], and the difference was statistically significant. Probiotics or synbiotics supplementation can reduce chemotherapy-induced complications in patients with gastrointestinal cancer and regulate the number of gut microbiotas to balance the intestinal microecology of the body.

Exploring the role of Fusobacterium nucleatum in colorectal cancer: implications for tumor proliferation and chemoresistance

Fusobacterium nucleatum (Fn) has been extensively studied for its connection to colorectal cancer (CRC) and its potential role in chemotherapy resistance. Studies indicate that Fn is commonly found in CRC tissues and is associated with unfavorable prognosis and treatment failure. It has been shown that Fn promotes chemoresistance by affecting autophagy, a cellular process that helps cells survive under stressful conditions. Additionally, Fn targets specific signaling pathways that activate particular microRNAs and modulate the response to chemotherapy. Understanding the current molecular mechanisms and investigating the importance of Fn-inducing chemoresistance could provide valuable insights for developing novel therapies. This review surveys the role of Fn in tumor proliferation, metastasis, and chemoresistance in CRC, focusing on its effects on the tumor microenvironment, gene expression, and resistance to conventional chemotherapy drugs. It also discusses the therapeutic implications of targeting Fn in CRC treatment and highlights the need for further research.

Periodontal bacteria influence systemic diseases through the gut microbiota

Many systemic diseases, including Alzheimer disease (AD), diabetes mellitus (DM) and cardiovascular disease, are associated with microbiota dysbiosis. The oral and intestinal microbiota are directly connected anatomically, and communicate with each other through the oral-gut microbiome axis to establish and maintain host microbial homeostasis. In addition to directly, periodontal bacteria may also be indirectly involved in the regulation of systemic health and disease through the disturbed gut. This paper provides evidence for the role of periodontal bacteria in systemic diseases via the oral-gut axis and the far-reaching implications of maintaining periodontal health in reducing the risk of many intestinal and parenteral diseases. This may provide insight into the underlying pathogenesis of many systemic diseases and the search for new preventive and therapeutic strategies.

Unveiling the Power of Gut Microbiome in Predicting Neoadjuvant Immunochemotherapy Responses in Esophageal Squamous Cell Carcinoma

The role of the gut microbiome in enhancing the efficacy of anticancer treatments like chemotherapy and radiotherapy is well acknowledged. However, there is limited empirical evidence on its predictive capabilities for neoadjuvant immunochemotherapy (NICT) responses in esophageal squamous cell carcinoma (ESCC). Our study fills this gap by comprehensively analyzing the gut microbiome's influence on NICT outcomes. We analyzed 16S rRNA gene sequences from 136 fecal samples from 68 ESCC patients before and after NICT, along with 19 samples from healthy controls. After NICT, marked microbiome composition changes were noted, including a decrease in ESCC-associated pathogens and an increase in beneficial microbes such as Limosilactobacillus, Lacticaseibacillus, and Staphylococcus. Baseline microbiota profiles effectively differentiated responders from nonresponders, with responders showing higher levels of short-chain fatty acid (SCFA)-producing bacteria such as Faecalibacterium, Eubacterium_eligens_group, Anaerostipes, and Odoribacter, and nonresponders showing increases in Veillonella, Campylobacter, Atopobium, and Trichococcus. We then divided our patient cohort into training and test sets at a 4:1 ratio and utilized the XGBoost-RFE algorithm to identify 7 key microbial biomarkers-Faecalibacterium, Subdoligranulum, Veillonella, Hungatella, Odoribacter, Butyricicoccus, and HT002. A predictive model was developed using LightGBM, which achieved an area under the receiver operating characteristic curve (AUC) of 86.8% [95% confidence interval (CI), 73.8% to 99.4%] in the training set, 76.8% (95% CI, 41.2% to 99.7%) in the validation set, and 76.5% (95% CI, 50.4% to 100%) in the testing set. Our findings underscore the gut microbiome as a novel source of biomarkers for predicting NICT responses in ESCC, highlighting its potential to enhance personalized treatment strategies and advance the integration of microbiome profiling into clinical practice for modulating cancer treatment responses.

From microbes to medicine: harnessing the power of the microbiome in esophageal cancer

Esophageal cancer (EC) is a malignancy with a high incidence and poor prognosis, significantly influenced by dysbiosis in the esophageal, oral, and gut microbiota. This review provides an overview of the roles of microbiota dysbiosis in EC pathogenesis, emphasizing their impact on tumor progression, drug efficacy, biomarker discovery, and therapeutic interventions. Lifestyle factors like smoking, alcohol consumption, and betel nut use are major contributors to dysbiosis and EC development. Recent studies utilizing advanced sequencing have revealed complex interactions between microbiota dysbiosis and EC, with oral pathogens such as Porphyromonas gingivalis and Fusobacterium nucleatum promoting inflammation and suppressing immune responses, thereby driving carcinogenesis. Altered esophageal microbiota, characterized by reduced beneficial bacteria and increased pathogenic species, further exacerbate local inflammation and tumor growth. Gut microbiota dysbiosis also affects systemic immunity, influencing chemotherapy and immunotherapy efficacy, with certain bacteria enhancing or inhibiting treatment responses. Microbiota composition shows potential as a non-invasive biomarker for early detection, prognosis, and personalized therapy. Novel therapeutic strategies targeting the microbiota-such as probiotics, dietary modifications, and fecal microbiota transplantation-offer promising avenues to restore balance and improve treatment efficacy, potentially enhancing patient outcomes. Integrating microbiome-focused strategies into current therapeutic frameworks could improve EC management, reduce adverse effects, and enhance patient survival. These findings highlight the need for further research into microbiota-tumor interactions and microbial interventions to transform EC treatment and prevention, particularly in cases of late-stage diagnosis and poor treatment response.

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.

Parvimonas micra forms a distinct bacterial network with oral pathobionts in colorectal cancer patients

BACKGROUND

Mounting evidence suggests a significant role of the gut microbiota in the development and progression of colorectal cancer (CRC). In particular, an over-representation of oral pathogens has been linked to CRC. The aim of this study was to further investigate the faecal microbial landscape of CRC patients, with a focus on the oral pathogens Parvimonas micra and Fusobacterium nucleatum.

METHODS

In this study, 16S rRNA sequencing was conducted using faecal samples from CRC patients (n = 275) and controls without pathological findings (n = 95).

RESULTS

We discovered a significant difference in microbial composition depending on tumour location and microsatellite instability (MSI) status, with P. micra, F. nucleatum, and Peptostreptococcus stomatis found to be more abundant in patients with MSI tumours. Moreover, P. micra and F. nucleatum were associated with a cluster of CRC-related bacteria including Bacteroides fragilis as well as with other oral pathogens such as P. stomatis and various Porphyromonas species. This cluster was distinctly different in the control group, suggesting its potential linkage with CRC.

CONCLUSIONS

Our results suggest a similar distribution of several CRC-associated bacteria within CRC patients, underscoring the importance of considering the concomitant presence of bacterial species in studies investigating the mechanisms of CRC development and progression.

The role of gut microbiota and metabolites in cancer chemotherapy

BACKGROUND

The microbiota inhabits the epithelial surfaces of hosts, which influences physiological functions from helping digest food and acquiring nutrition to regulate metabolism and shaping host immunity. With the deep insight into the microbiota, an increasing amount of research reveals that it is also involved in the initiation and progression of cancer. Intriguingly, gut microbiota can mediate the biotransformation of drugs, thereby altering their bioavailability, bioactivity, or toxicity.

AIM OF REVIEW

The review aims to elaborate on the role of gut microbiota and microbial metabolites in the efficacy and adverse effects of chemotherapeutics. Furthermore, we discuss the clinical potential of various ways to harness gut microbiota for cancer chemotherapy.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Recent evidence shows that gut microbiota modulates the efficacy and toxicity of chemotherapy agents, leading to diverse host responses to chemotherapy. Thereinto, targeting the microbiota to improve efficacy and diminish the toxicity of chemotherapeutic drugs may be a promising strategy in tumor treatment.

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.

Intratumoral microbiota in colorectal cancer: focus on specific distribution and potential mechanisms

Colorectal cancer (CRC) is one of the most prevalent and lethal malignant tumors globally, posing significant health risks and societal burdens. Recently, advancements in next-generation sequencing technology have identified CRC intratumoral microbiota, thereby opening up novel avenues for further research. This review synthesizes the current advancements in CRC intratumoral microbiota and their impact on CRC progression and discusses the disparities in the relative abundance and community composition of CRC intratumoral microbiota across various colorectal tumors based on their anatomical location and molecular subtypes, as well as the tumor stages, and spatial tumor distribution. Intratumoral microbiota predominantly influence CRC development by modulating colonic epithelial cells, tumor cells, and the tumor microenvironment. Mechanistically, they can cause DNA damage, apoptosis and epithelial-mesenchymal transition. The effects of different intratumoral microbiota on CRC have been shown to be two-fold. In the future, to address the limitations of existing studies, it is important to develop comprehensive experimental protocols and suitable in vitro models for elucidating more mechanisms of intratumoral microbiota on CRC, which will facilitate the clinical application of microbe-related therapeutic strategies in CRC and potentially other tumors.

E3 ubiquitin ligase gene BIRC3 modulates TNF-induced cell death pathways and promotes aberrant proliferation in rheumatoid arthritis fibroblast-like synoviocytes

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease characterized by synovitis, degradation of articular cartilage, and bone destruction. Fibroblast-like synoviocytes (FLS) play a central role in RA, producing a significant amount of inflammatory mediators such as tumor necrosis factor(TNF)-α and IL-6, which promote inflammatory responses within the joints. Moreover, FLS exhibit tumor-like behavior, including aggressive proliferation and enhanced anti-apoptotic capabilities, which collectively drive chronic inflammation and joint damage in RA. TNF is a major pro-inflammatory cytokine that mediates a series of signaling pathways through its receptor TNFR1, including NF-κB and MAPK pathways, which are crucial for inflammation and cell survival in RA. The abnormal proliferation and anti-apoptotic characteristics of FLS in RA may result from dysregulation in TNF-mediated cell death pathways such as apoptosis and necroptosis. Ubiquitination is a critical post-translational modification regulating these signaling pathways. E3 ubiquitin ligases, such as cIAP1/2, promote the ubiquitination and degradation of target proteins within the TNF receptor complex, modulating the signaling proteins. The high expression of the BIRC3 gene and its encoded protein, cIAP2, in RA regulates various cellular processes, including apoptosis, inflammatory signaling, immune response, MAPK signaling, and cell proliferation, thereby promoting FLS survival and inflammatory responses. Inhibiting BIRC3 expression can reduce the secretion of inflammatory cytokines by RA-FLS under both basal and inflammatory conditions and inhibit their proliferation. Although BIRC3 inhibitors show potential in RA treatment, their possible side effects must be carefully considered. Further research into the specific mechanisms of BIRC3, including its roles in cell signaling, apoptosis regulation, and immune evasion, is crucial for identifying new therapeutic targets and strategies.

Fusobacterium nucleatum: a novel regulator of antitumor immune checkpoint blockade therapy in colorectal cancer

Neoadjuvant immune checkpoint blockade (ICB) has achieved significant success in treating various cancers, leading to improved therapeutic responses and survival rates among patients. However, in colorectal cancer (CRC), ICB has yielded poor results in tumors that are mismatch repair proficient, microsatellite-stable, or have low levels of microsatellite instability (MSI-L), which account for up to 95% of CRC cases. The underlying mechanisms behind the lack of immune response in MSI-negative CRC to immune checkpoint inhibitors remain an open conundrum. Consequently, there is an urgent need to explore the intrinsic mechanisms and related biomarkers to enhance the intratumoral immune response and render the tumor "immune-reactive". Intestinal microbes, such as the oral microbiome member Fusobacterium nucleatum (F. nucleatum), have recently been thought to play a crucial role in regulating effective immunotherapeutic responses. Herein, we advocate the idea that a complex interplay involving F. nucleatum, the local immune system, and the tumor microenvironment (TME) significantly influences ICB responses. Several mechanisms have been proposed, including the regulation of immune cell proliferation, inhibition of T lymphocyte, natural killer (NK) cell function, and invariant natural killer T (iNKT) cell function, as well as modification of the TME. This review aims to summarize the latest potential roles and mechanisms of F. nucleatum in antitumor immunotherapies for CRC. Additionally, it discusses the clinical application value of F. nucleatum as a biomarker for CRC and explores novel strategies, such as nano-delivery systems, for modulating F. nucleatum to enhance the efficacy of ICB therapy.

Peptostreptococcus stomatis promotes colonic tumorigenesis and receptor tyrosine kinase inhibitor resistance by activating ERBB2-MAPK

Peptostreptococcus stomatis (P. stomatis) is enriched in colorectal cancer (CRC), but its causality and translational implications in CRC are unknown. Here, we show that P. stomatis accelerates colonic tumorigenesis in ApcMin/+ and azoxymethane/dextran sodium sulfate (AOM-DSS) models by inducing cell proliferation, suppressing apoptosis, and impairing gut barrier function. P. stomatis adheres to CRC cells through its surface protein fructose-1,6-bisphosphate aldolase (FBA) that binds to the integrin α6/β4 receptor on CRC cells, leading to the activation of ERBB2 and the downstream MEK-ERK-p90 cascade. Blockade of the FBA-integrin α6/β4 abolishes ERBB2-mitogen-activated protein kinase (MAPK) activation and the protumorigenic effect of P. stomatis. P. stomatis-driven ERBB2 activation bypasses receptor tyrosine kinase (RTK) blockade by EGFR inhibitors (cetuximab, erlotinib), leading to drug resistance in xenograft and spontaneous CRC models of KRAS-wild-type CRC. P. stomatis also abrogates BRAF inhibitor (vemurafenib) efficacy in BRAFV600E-mutant CRC xenografts. Thus, we identify P. stomatis as an oncogenic bacterium and a contributory factor for non-responsiveness to RTK inhibitors in CRC.

Unraveling the association between gut microbiota and chemotherapy efficacy: a two-sample Mendelian randomization study

Emerging evidence has underscored the complex link between gut microbiota and chemotherapy efficacy; however, establishing causality remains elusive due to confounding factors. This study, leveraging bidirectional two-sample Mendelian randomization (MR) analyses, explores the casual relationship between gut microbiota and chemotherapy efficacy. Utilizing genome-wide association study (GWAS) data from the MiBioGen consortium for gut microbiota and IEU Open GWAS for chemotherapy efficacy, we employed genetic variants as instrumental variables (IVs). The inverse variance weighted (IVW) method, weighted median estimator (WME), and MR-Egger regression method were applied, with sensitivity analyses ensuring robustness. Furthermore, we conducted reverse MR analyses between chemotherapy efficacy and identified significant gut microbial taxa. The results indicated that genus Butyricicoccus (OR = 3.7908, 95% CI: 1.4464-9.9350, P = 0.01), Dorea (OR = 3.3295, 95% CI: 1.2794-8.6643, P = 0.01), Hungatella (OR = 2.6284, 95% CI: 1.0548-6.5498, P = 0.04), and Turicibacter (OR = 2.5694, 95% CI: 1.0392-6.3526, P = 0.04) were positively associated with chemotherapy efficacy using the IVW method. Conversely, family Porphyromonadaceae (OR = 0.2283, 95% CI: 0.0699-0.7461, P = 0.01) and genus Eggerthella (OR = 0.4953, 95% CI: 0.2443-1.0043, P = 0.05) exhibited negative associations. WME demonstrated consistent results with IVW method only for genus Eggerthella (OR = 0.3343, 95% CI: 0.1298-0.8610, P = 0.02). No significant heterogeneity or horizontal pleiotropy was observed. Reverse MR analyses revealed no significant causal effect of chemotherapy on identified gut microbiota. This study sheds light on the intricate relationship between gut microbiota, with a particular emphasis on the genus Eggerthella, and chemotherapy efficacy, offering valuable insights for refining cancer treatment strategies.IMPORTANCEGlobal advancements in cancer treatment, particularly in chemotherapy, have notably decreased mortality rates in recent years. However, the correlation between gut microbiota and chemotherapy efficacy remains elusive. Our study, emphasizing the role of genus Eggerthella, represented a crucial advance in elucidating this intricate interplay. The identified associations offer potential therapeutic targets, contributing to global efforts for enhanced treatment precision and improved patient outcomes. Furthermore, our findings hold promise for personalized therapeutic interventions, shaping improved strategies in the ever-evolving landscape of cancer treatment.

Broadening oncological boundaries: the intratumoral microbiota

The microbiota of solid tumors was identified >100 years ago; however, heterogeneous composition and diversity have been revealed only recently. Growing evidence has suggested that several functional mechanisms of the intratumoral microbiota affect tumorigenesis and progression, suggesting that the intratumoral microbiota is a promising biomarker for multiple cancers. The low biomass of the intratumoral microbiota poses a major challenge to related research, thus necessitating the use of a multiple-modality integrated framework to resolve this dilemma. Advanced techniques such as single-cell sequencing provide significant clues, and the gradual optimization of functional experiments and culture-based methods enables deeper investigation of the underlying mechanisms involved. In this review, we outline the current state of research on the intratumoral microbiota and describe the challenges and comprehensive strategies for future research.

Prebiotic fibre mixtures counteract the manifestation of gut microbial dysbiosis induced by the chemotherapeutic 5-Fluorouracil (5-FU) in a validated in vitro model of the colon

BACKGROUND

5-Fluorouracil (5-FU) is used as an antineoplastic agent in distinct cancer types. Increasing evidence suggests that the gut microbiota might modulate 5-FU efficacy and toxicity, potentially affecting the patient's prognosis. The current experimental study investigated 5-FU-induced microbiota alterations, as well as the potential of prebiotic fibre mixtures (M1-M4) to counteract these shifts.

METHODS

A pooled microbial consortium was derived from ten healthy donors, inoculated in an in vitro model of the colon, and treated with 5-FU, with or without prebiotic fibre mixtures for 72 h. Four different prebiotic fibre mixtures were tested: M1 containing short-chain galacto-oligosaccharides (sc GOS), long-chain fructo-oligosaccharides (lcFOS), and low viscosity pectin (lvPect), M2 consisting of arabinoxylan, beta-glucan, pectin, and resistant starch, M3 which was a mixture of scGOS and lcFOS, and M4 containing arabinoxylan, beta-glucan, pectin, resistant starch, and inulin.

RESULTS

We identified 5-FU-induced changes in gut microbiota composition, but not in microbial diversity. Administration of prebiotic fibre mixtures during 5-FU influenced gut microbiota composition and taxa abundance. Amongst others, prebiotic fibre mixtures successfully stimulated potentially beneficial bacteria (Bifidobacterium, Lactobacillus, Anaerostipes, Weissella, Olsenella, Senegalimassilia) and suppressed the growth of potentially pathogenic bacteria (Klebsiella, Enterobacter) in the presence of 5-FU. The short-chain fatty acid (SCFA) acetate increased slightly during 5-FU, but even more during 5-FU with prebiotic fibre mixtures, while propionate was lower due to 5-FU with or without prebiotic fibre mixtures, compared to control. The SCFA butyrate and valerate did not show differences among all conditions. The branched-chain fatty acids (BCFA) iso-butyrate and iso-valerate were higher in 5-FU, but lower in 5-FU + prebiotics, compared to control.

CONCLUSIONS

These data suggest that prebiotic fibre mixtures represent a promising strategy to modulate 5-FU-induced microbial dysbiosis towards a more favourable microbiota, thereby possibly improving 5-FU efficacy and reducing toxicity, which should be evaluated further in clinical studies.

The Role of Natural Products from Herbal Medicine in TLR4 Signaling for Colorectal Cancer Treatment

The toll-like receptor 4 (TLR4) signaling pathway constitutes an intricate network of protein interactions primarily involved in inflammation and cancer. This pathway triggers intracellular signaling cascades, modulating transcription factors that regulate gene expression related to immunity and malignancy. Previous studies showed that colon cancer patients with low TLR4 expression exhibit extended survival times and the TLR4 signaling pathway holds a significant role in CRC pathogenesis. In recent years, traditional Chinese medicines (TCMs) have garnered substantial attention as an alternative therapeutic modality for CRC, primarily due to their multifaceted composition and ability to target multiple pathways. Emerging evidence indicates that specific TCM products, such as andrographolide, rosmarinic acid, baicalin, etc., have the potential to impede CRC development through the TLR4 signaling pathway. Here, we review the role and biochemical processes of the TLR4 signaling pathway in CRC, and natural products from TCMs affecting the TLR4 pathway. This review sheds light on potential treatment strategies utilizing natural TLR4 inhibitors for CRC, which contributes to the advancement of research and accelerates their clinical integration into CRC treatment.

Microbiome-driven anticancer therapy: A step forward from natural products

Human microbiomes, considered as a new emerging and enabling cancer hallmark, are increasingly recognized as critical effectors in cancer development and progression. Manipulation of microbiome revitalizing anticancer therapy from natural products shows promise toward improving cancer outcomes. Herein, we summarize our current understanding of the human microbiome-driven molecular mechanisms impacting cancer progression and anticancer therapy. We highlight the potential translational and clinical implications of natural products for cancer prevention and treatment by developing targeted therapeutic strategies as adjuvants for chemotherapy and immunotherapy against tumorigenesis. The challenges and opportunities for future investigations using modulation of the microbiome for cancer treatment are further discussed in this review.

Squalene epoxidase promotes the chemoresistance of colorectal cancer via (S)-2,3-epoxysqualene-activated NF-κB

BACKGROUND

While de novo cholesterol biosynthesis plays a crucial role in chemotherapy resistance of colorectal cancer (CRC), the underlying molecular mechanism remains poorly understood.

METHODS

We conducted cell proliferation assays on CRC cells with or without depletion of squalene epoxidase (SQLE), with or without 5-fluorouracil (5-FU) treatment. Additionally, a xenograft mouse model was utilized to explore the impact of SQLE on the chemosensitivity of CRC to 5-FU. RNA-sequencing analysis and immunoblotting analysis were performed to clarify the mechanism. We further explore the effect of SQLE depletion on the ubiquitin of NF-κB inhibitor alpha (IκBα) and (S)-2,3-epoxysqualene on the binding of IκBα to beta-transducin repeat containing E3 ubiquitin protein ligase (BTRC) by using immunoprecipitation assay. In addition, a cohort of 272 CRC patients were selected for our clinical analyses.

RESULTS

Mechanistically, (S)-2,3-epoxysqualene promotes IκBα degradation and subsequent NF-κB activation by enhancing the interaction between BTRC and IκBα. Activated NF-κB upregulates the expression of baculoviral IAP repeat containing 3 (BIRC3), sustains tumor cell survival after 5-FU treatment and promotes 5-FU resistance of CRC in vivo. Notably, the treatment of terbinafine, an inhibitor of SQLE commonly used as antifungal drug in clinic, enhances the sensitivity of CRC to 5-FU in vivo. Additionally, the expression of SQLE is associated with the prognosis of human CRC patients with 5-FU-based chemotherapy.

CONCLUSIONS

Thus, our finding not only demonstrates a new role of SQLE in chemoresistance of CRC, but also reveals a novel mechanism of (S)-2,3-epoxysqualene-dependent NF-κB activation, implicating the combined potential of terbinafine for 5-FU-based CRC treatment.

Unveiling intratumoral microbiota: An emerging force for colorectal cancer diagnosis and therapy

Microbes, including bacteria, viruses, fungi, and other eukaryotic organisms, are commonly present in multiple organs of the human body and contribute significantly to both physiological and pathological processes. Nowadays, the development of sequencing technology has revealed the presence and composition of the intratumoral microbiota, which includes Fusobacterium, Bifidobacteria, and Bacteroides, and has shed light on the significant involvement in the progression of colorectal cancer (CRC). Here, we summarized the current understanding of the intratumoral microbiota in CRC and outline the potential translational and clinical applications in the diagnosis, prevention, and treatment of CRC. We focused on reviewing the development of microbial therapies targeting the intratumoral microbiota to improve the efficacy and safety of chemotherapy and immunotherapy for CRC and to identify biomarkers for the diagnosis and prognosis of CRC. Finally, we emphasized the obstacles and potential solutions to translating the knowledge of the intratumoral microbiota into clinical practice.

Microbiome and cancer: from mechanistic implications in disease progression and treatment to development of novel antitumoral strategies

Cancer is a very aggressive disease and one of mankind's most important health problems, causing numerous deaths each year. Its etiology is complex, including genetic, gender-related, infectious diseases, dysbiosis, immunological imbalances, lifestyle, including dietary factors, pollution etc. Cancer patients also become immunosuppressed, frequently as side effects of chemotherapy and radiotherapy, and prone to infections, which further promote the proliferation of tumor cells. In recent decades, the role and importance of the microbiota in cancer has become a hot spot in human biology research, bringing together oncology and human microbiology. In addition to their roles in the etiology of different cancers, microorganisms interact with tumor cells and may be involved in modulating their response to treatment and in the toxicity of anti-tumor therapies. In this review, we present an update on the roles of microbiota in cancer with a focus on interference with anticancer treatments and anticancer potential.

Recent progress in nanomaterials for bacteria-related tumor therapy

Many studies suggest that tumor microbiome closely relates to the oncogenesis and anti-tumor responses in multiple cancer types (e.g., colorectal cancer (CRC), breast cancer, lung cancer and pancreatic cancer), thereby raising an emerging research area of bacteria-related tumor therapy. Nanomaterials have long been used for both cancer and bacterial infection treatment, holding great potential for bacteria-related tumor therapy. In this review, we summarized recent progress in nanomaterials for bacteria-related tumor therapy. We focus on the types and mechanisms of pathogenic bacteria in the development and promotion of cancers and emphasize how nanomaterials work. We also briefly discuss the design principles and challenges of nanomaterials for bacteria-related tumor therapy. We hope this review can provide some insights into this emerging and rapidly growing research area.

Tumor-resident microbes: the new kids on the microenvironment block

Tumor-resident microbes (TRM) are an integral component of the tumor microenvironment (TME). TRM can influence tumor growth, distant dissemination, and response to therapies by interfering with molecular pathways in tumor cells as well as with other components of the TME. Novel technologies are improving the identification and visualization of cell type-specific microbes in the TME. The mechanisms that mediate the role of TRM at the primary tumors and metastatic sites are being elucidated. This knowledge is providing novel perspectives for targeting microbes or using microbial interventions for cancer interception or therapy.

Bacterial DnaK reduces the activity of anti-cancer drugs cisplatin and 5FU

BACKGROUND

Chemotherapy is a primary treatment for cancer, but its efficacy is often limited by cancer-associated bacteria (CAB) that impair tumor suppressor functions. Our previous research found that Mycoplasma fermentans DnaK, a chaperone protein, impairs p53 activities, which are essential for most anti-cancer chemotherapeutic responses.

METHODS

To investigate the role of DnaK in chemotherapy, we treated cancer cell lines with M. fermentans DnaK and then with commonly used p53-dependent anti-cancer drugs (cisplatin and 5FU). We evaluated the cells' survival in the presence or absence of a DnaK-binding peptide (ARV-1502). We also validated our findings using primary tumor cells from a novel DnaK knock-in mouse model. To provide a broader context for the clinical significance of these findings, we investigated human primary cancer sequencing datasets from The Cancer Genome Atlas (TCGA). We identified F. nucleatum as a CAB carrying DnaK with an amino acid composition highly similar to M. fermentans DnaK. Therefore, we investigated the effect of F. nucleatum DnaK on the anti-cancer activity of cisplatin and 5FU.

RESULTS

Our results show that both M. fermentans and F. nucleatum DnaKs reduce the effectiveness of cisplatin and 5FU. However, the use of ARV-1502 effectively restored the drugs' anti-cancer efficacy.

CONCLUSIONS

Our findings offer a practical framework for designing and implementing novel personalized anti-cancer strategies by targeting specific bacterial DnaKs in patients with poor response to chemotherapy, underscoring the potential for microbiome-based personalized cancer therapies.

Remotely Controllable Supramolecular Nanomedicine for Drug-Resistant Colorectal Cancer Therapy Caused by Fusobacterium nucleatum

Fusobacterium nucleatum (Fn) existing in the community of colorectal cancer (CRC) promotes CRC progression and causes chemotherapy resistance. Despite great efforts that have been made to overcome Fn-induced chemotherapy resistance by co-delivering antibacterial agents and chemotherapeutic drugs, increasing the drug-loading capacity and enabling controlled release of drugs remain challenging. In this study, a novel supramolecular upconversion nanoparticle (SUNP) is constructed by incorporating a positively charged polymer (PAMAM-LA-CD) with Fn inhibition capacity, a negatively charged platinum (IV) oxaliplatin prodrug (OXA-COOH), upconversion nanoparticle (UCNPs) and polyethylene glycol-azobenzene (PEG-Azo) to enhance drug-loading and enable on-demand drug release for drug-resistant CRC treatment. SUNPs exhibit high drug-loading capacity (30.8%) and good structural stability under normal physiological conditions, while disassembled upon exogenous NIR excitation and endogenous azo reductase in the CRC microenvironment to trigger drug release. In vitro and in vivo studies demonstrate that SUNPs presented good biocompatibility and robust performance to overcome chemoresistance, thereby significantly inhibiting Fn-infected cancer cell proliferation. This study leverages multiple dynamic chemical designs to integrate both advantages of drug loading and release in a single system, which provides a promising candidate for precision therapy of bacterial-related drug-resistant cancers.

A rapid and sensitive CRISPR-Cas12a for the detection of Fusobacterium nucleatum

Fusobacterium nucleatum (Fn), as a conditional pathogen, can cause a range of oral and gastrointestinal diseases. However, existing clinical detection methods require expensive equipment and complex procedures, which are inconvenient for large-scale screening in epidemiological research. The purpose of this study was to establish a reliable, rapid, and inexpensive detection method based on CRISPR/Cas12a technology for the detection of Fn. Specific recombinase polymerase amplification (RPA) primer sequences and crRNA sequences were designed based on the nusG gene of Fn. Subsequently, a fluorescence assay and a lateral flow immunoassay were established using the RPA and CRISPR-Cas12a system (RPA-CRISPR-Cas12a). Sensitivity validation revealed a limit of detection of 5 copies/µL. This method could distinguish Fn from other pathogens with excellent specificity. Furthermore, the RPA-CRISPR-Cas12a assay was highly consistent with the classical quantitative real-time PCR method when testing periodontal pocket samples. This makes it a promising method for the detection of Fn and has the potential to play an increasingly important role in infectious disease testing.IMPORTANCEFusobacterium nucleatum (Fn) naturally exists in the microbial communities of the oral and gastrointestinal tracts of healthy individuals and can cause inflammatory diseases in the oral and gastrointestinal tracts. Recent studies have shown that Fn is closely associated with the occurrence and development of gastrointestinal cancer. Therefore, the detection of Fn is very important. Unlike the existing clinical detection methods, this study established a fluorescence-based assay and lateral flow immunoassay based on the RPA and CRISPR-Cas12a system (RPA-CRISPR-Cas12a), which is fast, reliable, and inexpensive and can complete the detection within 30-40 minutes. This makes it a promising method for the detection of Fn and has the potential to play an increasingly important role in infectious disease testing.

Distinct intratumoral microbiome of young-onset and average-onset colorectal cancer

BACKGROUND

The unexplained rise of young-onset CRC (yoCRC, age <50 years) is of concern. Evidence suggests that microbial dysbiosis may be a contributing factor, but the tumor microbial profile of yoCRC in comparison to average-onset CRC (aoCRC, age >60) has not been fully investigated.

METHODS

16S rRNA amplicon sequencing was performed in tumor and paired adjacent non-malignant fresh frozen tissue specimens prospectively collected from 136 yoCRC and 140 aoCRC patients. Phyloseq, microbiomeSeq, metagenomeSeq, and NetComi were utilized for bioinformatics analysis. Statistical tests included Fisher's exact test, ANOVA, PERMANOVA with Bonferroni correction, linear regression, and Wilcoxon test. p-value <0.05 was considered statistically significant.

FINDINGS

yoCRC patients were more likely to have left-sided (72.8 vs. 54.3%), rectal (36.7% vs. 25%), and stage IV (28% vs. 15%) tumors. yoCRC tumors had significantly higher microbial alpha diversity (p = 1.5 × 10-5) and varied beta diversity (R2 = 0.31, p = 0.013) than aoCRC tumors. yoCRC tumors were enriched with Akkermansia and Bacteroides, whereas aoCRC tumors showed greater relative abundances of Bacillus, Staphylococcus, Listeria, Enterococcus, Pseudomonas, Fusobacterium, and Escherichia/Shigella. Akkermansia had a predominantly negative correlation with the microbial communities in yoCRC tumors. yoCRC and aoCRC tumors had distinct microbial profiles associated with tumor location, sidedness, stage, and obesity. Fusobacterium (R2 = -0.23, p = 0.001) and Akkermansia (R2 = 0.05, p = 0.001) abundance correlated with overall survival in yoCRC.

INTERPRETATION

Our study provides a comprehensive understanding of the microbial perturbations in yoCRC tumors. We identify microbial candidates that may highlight a distinct pathogenesis of yoCRC and serve as preventive, diagnostic, and therapeutic targets.

FUNDING

Sondra and Stephen Hardis Chair in Oncology Research (A.A.K.).

Emerging strategies for combating Fusobacterium nucleatum in colorectal cancer treatment: Systematic review, improvements and future challenges

Colorectal cancer (CRC) is generally characterized by a high prevalence of Fusobacterium nucleatum (F. nucleatum), a spindle-shaped, Gram-negative anaerobe pathogen derived from the oral cavity. This tumor-resident microorganism has been closely correlated with the occurrence, progression, chemoresistance and immunosuppressive microenvironment of CRC. Furthermore, F. nucleatum can specifically colonize CRC tissues through adhesion on its surface, forming biofilms that are highly resistant to commonly used antibiotics. Accordingly, it is crucial to develop efficacious non-antibiotic approaches to eradicate F. nucleatum and its biofilms for CRC treatment. In recent years, various antimicrobial strategies, such as natural extracts, inorganic chemicals, organic chemicals, polymers, inorganic-organic hybrid materials, bacteriophages, probiotics, and vaccines, have been proposed to combat F. nucleatum and F. nucleatum biofilms. This review summarizes the latest advancements in anti-F. nucleatum research, elucidates the antimicrobial mechanisms employed by these systems, and discusses the benefits and drawbacks of each antimicrobial technology. Additionally, this review also provides an outlook on the antimicrobial specificity, potential clinical implications, challenges, and future improvements of these antimicrobial strategies in the treatment of CRC.

The role of microbiomes in gastrointestinal cancers: new insights

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