The human gut bacterial genotoxin colibactin alkylates DNA

Exploring preventive and treatment strategies for oral cancer: Modulation of signaling pathways and microbiota by probiotics

The evidence suggests that the microbiome plays a crucial role in cancer development. The oral cavity has many microorganisms that can influence oral cancer progression. Understanding the mechanisms and signaling pathways of the oral, gum, and teeth microbiome in tumor progression can lead to new treatment strategies. Probiotics, which are friendly microorganisms, have shown potential as anti-cancer agents. These positive characteristics of probiotic strains make them suitable for cancer prevention or treatment. The oral-gut microbiome axis supports health and homeostasis, and imbalances in the oral microbiome can disrupt immune signaling pathways, epithelial barriers, cell cycles, apoptosis, genomic stability, angiogenesis, and metabolic processes. Changes in the oral microbiome in oral cancer may suggest using probiotics-based treatments for their direct or indirect positive roles in cancer development, progression, and metastasis, specifically oral squamous cell carcinoma (OSCC). Here, reported relationships between probiotics, oral microbiota, and oral cancer are summarized.

Colibactin Exerts Androgen-dependent and -independent Effects on Prostate Cancer

BACKGROUND AND OBJECTIVE

The etiology of prostate cancer (PC) is multifactorial and poorly understood. It has been suggested that colibactin-producing Escherichia coli positive for the pathogenicity island pks (pks+) initiate cancers via induction of genomic instability. In PC, androgens promote oncogenic translocations. Our aim was to investigate the association of pks+E. coli with PC diagnosis and molecular architecture, and its relationship with androgens.

METHODS

We quantified the association of pks+E. coli with PC diagnosis in a volunteer-sampled 235-person cohort from two institutional practices (UT San Antonio). We then used colibactin 742 and DNA/RNA sequencing to evaluate the effects of colibactin 742, dihydrotestosterone (DHT), and their combination in vitro.

KEY FINDINGS AND LIMITATIONS

Colibactin exposure was positively associated with PC diagnosis (p = 0.04) in our clinical cohort, and significantly increased replication fork stalling and fusions in vitro (p < 0.01). Combined in vitro exposure to colibactin 742 and DHT induced more somatic mutations of all types than exposure to either alone. The combination also elicited kataegis, with a higher density of somatic point mutations. Laboratory analyses were conducted using a single cell line, which limited our ability to fully recapitulate the complexity of PC etiology.

CONCLUSIONS AND CLINICAL IMPLICATIONS

Our findings are consistent with synergistic induction of genome instability and kataegis by colibactin 742 and DHT in cell culture. Colibactin-producing pks+ E. coli may plausibly contribute to PC etiology.

PATIENT SUMMARY

We investigated whether a bacterial toxin that is linked to colon cancer can also cause prostate cancer. Our results support this idea by showing a link between the toxin and prostate cancer diagnosis in a large patient population. We also found that this toxin causes genetic dysfunction in prostate cancer cells when combined with testosterone.

The Role of Microbiota in Upper Gastrointestinal Cancers

The gut microbiota significantly impacts the development and progression of upper gastrointestinal (GI) cancers, including esophageal and gastric cancers. Microbial dysbiosis contributes to carcinogenesis through mechanisms such as inflammation, immune modulation, and direct DNA damage. Techniques for sampling oral, esophageal, and gastric microbiota vary, with standardization being essential for reliable results. Barrett's esophagus (BE) and esophageal adenocarcinoma (EAC) are associated with an enrichment of Gram-negative bacteria, promoting inflammation and cancer progression. Esophageal squamous cell carcinoma (ESCC) also shows distinct microbial patterns, with reduced diversity and increased harmful bacteria like Porphyromonas gingivalis and Fusobacterium nucleatum. In gastric cancer (GC), Helicobacter pylori (HP) and non-HP gastric microbiota play significant roles, with diverse microbial communities contributing to cancer development through nitrate reduction, immune modulation, and inflammation. Emerging evidence highlights the role of non-HP bacteria in promoting carcinogenesis, with specific taxa like Fusobacterium nucleatum and Lactobacillus influencing tumor growth and immune evasion. Further research is needed to elucidate the complex interactions between gut microbiota and upper GI cancers, paving the way for novel diagnostic and therapeutic approaches. Understanding these microbial dynamics offers potential for microbiota-based interventions, improving the early detection, prognosis, and treatment of upper GI cancers. This comprehensive review summarizes the available evidence on the role of microbiota in upper GI oncology and the need for continued exploration in this field.

Microbiota mechanisms in cancer progression and therapy

The composition of the microbiota in patients has been shown to correlate with cancer progression and response to therapy, highlighting unique opportunities to improve patient outcomes. In this review, we discuss the challenges and advancements in understanding the chemical mechanisms of specific microbiota species, pathways, and molecules involved in cancer progression and treatment. We also describe the modulation of cancer and immunotherapy by the microbiota, along with approaches for investigating microbiota enzymes and metabolites. Elucidating these specific microbiota mechanisms and molecules should offer new opportunities for developing enhanced diagnostics and therapeutics to improve outcomes for cancer patients. Nonetheless, many microbiota mechanisms remain to be determined and require innovative chemical genetic approaches.

Structural study on human microbiome-derived polyketide synthases that assemble genotoxic colibactin

Colibactin, a human microbiome-derived genotoxin, promotes colorectal cancer by damaging the host gut epithelial genomes. While colibactin is synthesized via a hybrid non-ribosomal peptide synthetase (NRPS)-polyketide synthase (PKS) pathway, known as pks or clb, the structural details of its biosynthetic enzymes remain limited, hindering our understanding of its biosynthesis and clinical application. In this study, we report the cryo-EM structures of two colibactin-producing PKS enzymes, ClbC and ClbI, captured in different reaction states using a substrate-mimic crosslinker. Our structural analysis revealed the binding sites of carrier protein (CP) domains of the ClbC and ClbI on their ketosynthase (KS) domains. Further, we identified a novel NRPS-PKS docking interaction between ClbI and its upstream enzyme, ClbH, mediated by the C-terminal peptide ClbH and the dimeric interface of ClbI, establishing a 1:2 stoichiometry. These findings advance our understanding of colibactin assembly line and provide broader insights into NRPS-PKS natural product biosynthesis mechanisms.

Thomasclavelia ramosa and alcohol-related hepatocellular carcinoma: a microbial culturomics study

BACKGROUND

Gut microbiota alteration is implicated in the pathogenesis of alcoholic liver disease (ALD) and associated hepatocellular carcinoma (HCC). No study has characterized the dysbiosis associated with ALD by microbial culturomics, which certifies viability and allows pathobiont strain candidates to be characterized.

METHODS

A case-control study (n = 59) was conducted on patients with ALD without HCC (ALD-NoHCC, n = 16), ALD with HCC (ALD-HCC, n = 19) and controls (n = 24) groups. 16 S rRNA amplicon sequencing and microbial culturomics were used as complementary methods for gut microbiome profiling.

RESULTS

Compared to the control group, Thomasclavelia ramosa and Gemmiger formicilis were significantly increased in the ALD-HCC group and Mediterraneibacter gnavus was significantly increased in the ALD-NoHCC group using 16 S rRNA sequencing. By microbial culturomics, T. ramosa was detected in all ALD samples (100%), and the most enriched since cultivated in only a small proportion of controls (20%, p < 0.001).

CONCLUSIONS

T. ramosa, identified by culturomics and 16 rRNA sequencing, may be associated with ALD and ALD-HCC. These results highlight the potential role of T. ramosa in liver cancer, in line with its genotoxic properties and its tumor growth-promoting effect in gnotobiotic mice recently reported.

Physiological drivers of pks+ E. coli in colorectal cancer

Colorectal cancer (CRC) is a significant global health challenge, with rising incidence, particularly among individuals under 50. Increasing evidence highlights the gut microbiota as key contributors to CRC development, with certain oncogenic bacteria influencing cancer initiation, progression, and therapy response. Among these is pks+ Escherichia coli, which produces colibactin, a genotoxic compound that induces DNA damage and leaves a distinct mutational signature in healthy individuals and CRC patients. While research has focused on its genotoxic effects, this review examines the kinetics of colibactin-induced mutations and the epithelial and environmental changes that promote E. coli expansion and colibactin exposure. We also explore the broader role of pks+ E. coli in cancer initiation and progression beyond genotoxicity, and discuss potential therapeutic approaches.

New insights into gut microbiota-prostate cancer crosstalk

Recent evidence underscores a reciprocal relationship between the gut microbiota and prostate cancer (PCa). Dysbiosis, often driven by Western dietary habits and antibiotic use, can heighten systemic inflammation and hinder antitumor immunity, thereby fostering PCa onset and progression. Conversely, certain gut microbes and their metabolites may protect against tumor growth by modulating immune and hormonal pathways that impact therapeutic responses, including androgen deprivation therapy (ADT). Emerging evidence links gut microbial shifts to PCa aggressiveness, potentially sustaining local androgen production and promoting resistance. In this review, we explore current understanding of the gut-PCa interplay, highlighting key knowledge gaps and the need for further research to clarify how targeting the microbiome might influence PCa outcomes.

Gut microbiota in cancer initiation, development and therapy

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

The power of microbes: the key role of gut microbiota in the initiation and progression of colorectal cancer

Colorectal cancer (CRC) is ranked as the third most prevalent malignancy and is a leading cause of cancer-related mortality globally, significantly affecting the health and longevity of middle-aged individuals and the elderly. The primary risk factors for CRC are mainly due to unhealthy dietary habits and lifestyle choices, and they have been shown to profoundly influence the composition of the gut microbiota. Given that dietary patterns are critical determinants of gut microbial diversity, a compelling association exists between gut microbiota and the pathogenesis of CRC. Recent research has increasingly focused on the intricate interplay between gut microbiota and CRC, exploring its role in disease initiation, progression, and the modulation of host immune responses. Investigations have demonstrated that certain specific microbial communities can promote inflammation, disrupt metabolic pathways, and produce carcinogenic compounds, thereby contributing to the development of CRC. Conversely, a diverse and balanced gut microbiome may confer protective effects against cancer through mechanisms such as the production of short-chain fatty acids and the enhancement of intestinal barrier integrity. This article provides a comprehensive overview of the characteristics of the gut microbial community and its complex relationship with CRC. It highlights potential mechanisms through which gut microbiota may influence CRC pathogenesis, including chronic inflammation, toxins, metabolites, epigenetic dysregulation, and immune regulatory dysfunction. Additionally, this review summarizes innovative strategies for CRC prevention and treatment, emphasizing the therapeutic potential of probiotics and natural plant extracts. By elucidating these connections, this work aims to enhance the understanding of the gut microbiome's role in CRC.

Dietary fibre counters the oncogenic potential of colibactin-producing Escherichia coli in colorectal cancer

Diet, microbiome, inflammation and host genetics have been linked to colorectal cancer development; however, it is not clear whether and how these factors interact to promote carcinogenesis. Here we used Il10-/- mice colonized with bacteria previously associated with colorectal cancer: enterotoxigenic Bacteroides fragilis, Helicobacter hepaticus or colibactin-producing (polyketide synthase-positive (pks+)) Escherichia coli and fed either a low-carbohydrate (LC) diet deficient in soluble fibre, a high-fat and high-sugar diet, or a normal chow diet. Colonic polyposis was increased in mice colonized with pks+ E. coli and fed the LC diet. Mechanistically, mucosal inflammation was increased in the LC-diet-fed mice, leading to diminished colonic PPAR-γ signalling and increased luminal nitrate levels. This promoted both pks+ E. coli growth and colibactin-induced DNA damage. PPAR-γ agonists or supplementation with dietary soluble fibre in the form of inulin reverted inflammatory and polyposis phenotypes. The pks+ E. coli also induced more polyps in mismatch-repair-deficient mice by inducing a senescence-associated secretory phenotype. Moreover, oncogenic effects were further potentiated by inflammatory triggers in the mismatch-repair-deficient model. These data reveal that diet and host genetics influence the oncogenic potential of a common bacterium.

De-coding the complex role of microbial metabolites in cancer

The human microbiome, an intricate ecosystem of trillions of microbes residing across various body sites, significantly influences cancer, a leading cause of morbidity and mortality worldwide. Recent studies have illuminated the microbiome's pivotal role in cancer development, either through direct cellular interactions or by secreting bioactive compounds such as metabolites. Microbial metabolites contribute to cancer initiation through mechanisms such as DNA damage, epithelial barrier dysfunction, and chronic inflammation. Furthermore, microbial metabolites exert dual roles on cancer progression and response to therapy by modulating cellular metabolism, gene expression, and signaling pathways. Understanding these complex interactions is vital for devising new therapeutic strategies. This review highlights microbial metabolites as promising targets for cancer prevention and treatment, emphasizing their impact on therapy responses and underscoring the need for further research into their roles in metastasis and therapy resistance.

Heterologous Expression of a Cryptic BGC from Bilophila sp. Provides Access to a Novel Family of Antibacterial Thiazoles

Human health is greatly influenced by the gut microbiota and microbiota imbalance can lead to the development of diseases. It is widely acknowledged that the interaction of bacteria within competitive ecosystems is influenced by their specialized metabolites, which act, e.g., as antibacterials or siderophores. However, our understanding of the occurrence and impact of such natural products in the human gut microbiome remains very limited. As arylthiazole siderophores are an emerging family of growth-promoting molecules in pathogenic bacteria, we analyzed a metagenomic data set from the human microbiome and thereby identified the bil-BGC, which originates from an uncultured Bilophila strain. Through gene synthesis and BGC assembly, heterologous expression and mutasynthetic experiments, we discovered the arylthiazole natural products bilothiazoles A-F. While established activities of related molecules indicate their involvement in metal-binding and -uptake, which could promote the growth of pathogenic strains, we also found antibiotic activity for some bilothiazoles. This is supported by biosensor-experiments, where bilothiazoles C and E show PrecA-suppressing activity, while bilothiazole F induces PblaZ, a biosensor characteristic for β-lactam antibiotics. These findings serve as a starting point for investigating the role of bilothiazoles in the pathogenicity of Bilophila species in the gut.

Colorectal Organoids: Models, Imaging, Omics, Therapy, Immunology, and Ethics

Colorectal epithelium was the first long-term 3D organoid culture established in vitro. Identification of the key components essential for the long-term survival of the stem cell niche allowed an indefinite propagation of these cultures and the modulation of their differentiation into various lineages of mature intestinal epithelial cells. While these methods were eventually adapted to establish organoids from different organs, colorectal organoids remain a pioneering model for the development of new applications in health and disease. Several basic and applicative aspects of organoid culture, modeling, monitoring and testing are analyzed in this review. We also tackle the ethical problems of biobanking and distribution of these precious research tools, frequently confined in the laboratory of origin or condemned to destruction at the end of the project.

The Prevalence of Polyketide Synthase-Positive E. coli in Cystic Fibrosis

Cystic fibrosis (CF) patients experience higher risks of colorectal cancer but the pathogenesis is unclear. In the general population, polyketide synthase-positive (pks+) E. coli is implicated in intestinal carcinogenesis via the production of colibactin; however, the relevance in CF is unknown. In this study, we investigate pks+E. coli prevalence in CF and potential associations between pks+E. coli, gastrointestinal inflammation, and microbiome dynamics with fecal calprotectin and 16SrRNA gene taxonomic data. Cross-sectional analysis demonstrated no difference in pks+E. coli carriage between CF patients and healthy controls, 21/55 (38%) vs. 26/55 (47%), p = 0.32. Pks+E. coli was not associated with significant differences in mean (SD) calprotectin concentration (124 (154) vs. 158 (268) mg/kg; p = 0.60), microbial richness (159 (76.5) vs. 147 (70.4); p = 0.50) or Shannon diversity index (2.78 (0.77) vs. 2.65 (0.74); p = 0.50) in CF. Additionally, there was no association with exocrine pancreatic status (p = 0.2) or overall antibiotic use (p = 0.6). Longitudinally, CF subjects demonstrated intra-individual variation in pks+E. coli presence but no significant difference in overall prevalence. Future investigation into the effects of repeat exposure on risk profile and analysis of older CF cohorts is necessary to identify if associations with colorectal cancer exist.

The role of the urinary microbiome in genitourinary cancers

Genitourinary cancers account for 20% of cancer instances globally and pose a substantial burden. The microbiome, defined as the ecosystem of organisms that reside within and on the human body, seems to be closely related to multiple cancers. Research on the gut microbiome has yielded substantial insights into the interactions of this entity with the immune system and cancer therapeutic efficacy, whereas the urinary microbiome has been relatively less well-studied. Advances in next-generation sequencing technologies led to new discoveries in the urinary microbiome, which might aid in early detection, risk stratification and personalized treatment strategies in genitourinary cancers. Mechanistic investigations have also suggested a role for the urinary microbiome in modulating the tumour microenvironment and host immune response. For example, distinct urinary microbial signatures have been linked to bladder cancer occurrence and recurrence risk, with specific taxa associated with cytokine production and inflammation. Urinary microbiome signatures have also been explored as potential biomarkers for non-invasive cancer detection. However, challenges remain in standardizing methodologies, validating findings across studies, and establishing causative mechanisms. As investigations into the urinary microbiome continue to evolve, so does the potential for developing microbiome-modulating therapies and enhancing diagnostic capabilities to improve outcomes in patients with genitourinary cancers.

Unveiling the link between chronic inflammation and cancer

The highly nuanced transition from an inflammatory process to tumorigenesis is of great scientific interest. While it is well known that environmental stimuli can cause inflammation, less is known about the oncogenic modifications that chronic inflammation in the tissue microenvironment can bring about, as well as how these modifications can set off pro-tumorigenic processes. It is clear that no matter where the environmental factors come from, maintaining an inflammatory microenvironment encourages carcinogenesis. In addition to encouraging angiogenesis and metastatic processes, sustaining the survival and proliferation of malignant transformed cells, and possibly altering the efficacy of therapeutic agents, inflammation can negatively regulate the antitumoral adaptive and innate immune responses. Because chronic inflammation has multiple pathways involved in tumorigenesis and metastasis, it has gained recognition as a marker of cancer and a desirable target for cancer therapy. Recent advances in our knowledge of the molecular mechanisms that drive cancer's progression demonstrate that inflammation promotes tumorigenesis and metastasis while suppressing anti-tumor immunity. In many solid tumor types, including breast, lung, and liver cancer, inflammation stimulates the activation of oncogenes and impairs the body's defenses against the tumor. Additionally, it alters the microenvironment of the tumor. As a tactical approach to cancer treatment, these findings have underscored the importance of targeting inflammatory pathways. This review highlights the role of inflammation in cancer development and metastasis, focusing on its impact on tumor progression, immune suppression, and therapy resistance. It examines current anti-inflammatory strategies, including NSAIDs, cytokine modulators, and STAT3 inhibitors, while addressing their potential and limitations. The review emphasizes the need for further research to unravel the complex mechanisms linking inflammation to cancer progression and identify molecular targets for specific cancer subtypes.

Unlocking the Microbial Symphony: The Interplay of Human Microbiota in Cancer Immunotherapy Response

INTRODUCTION

The emergence of cancer immunotherapy has revolutionized cancer treatment, offering remarkable outcomes for patients across various malignancies. However, the heterogeneous response to immunotherapy underscores the necessity of understanding additional factors influencing treatment efficacy. Among these factors, the human microbiota has garnered significant attention for its potential role in modulating immune response. Body: This review explores the intricate relationship between the human microbiota and cancer immunotherapy, highlighting recent advances and potential mechanisms underlying microbial influence on treatment outcomes.

CONCLUSION

Insights into the microbiome's impact on immunotherapy response not only deepen our understanding of cancer pathogenesis but also hold promise for personalized therapeutic strategies aimed at optimizing patient outcomes.

Structure-Based Modeling of the Gut Bacteria-Host Interactome Through Statistical Analysis of Domain-Domain Associations Using Machine Learning

The gut microbiome, a complex ecosystem of microorganisms, plays a pivotal role in human health and disease. The gut microbiome's influence extends beyond the digestive system to various organs, and its imbalance is linked to a wide range of diseases, including cancer and neurodevelopmental, inflammatory, metabolic, cardiovascular, autoimmune, and psychiatric diseases. Despite its significance, the interactions between gut bacteria and human proteins remain understudied, with less than 20,000 experimentally validated protein interactions between the host and any bacteria species. This study addresses this knowledge gap by predicting a protein-protein interaction network between gut bacterial and human proteins. Using statistical associations between Pfam domains, a comprehensive dataset of over one million experimentally validated pan-bacterial-human protein interactions, as well as inter- and intra-species protein interactions from various organisms, were used for the development of a machine learning-based prediction method to uncover key regulatory molecules in this dynamic system. This study's findings contribute to the understanding of the intricate gut microbiome-host relationship and pave the way for future experimental validation and therapeutic strategies targeting the gut microbiome interplay.

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.

Signalling and molecular pathways, overexpressed receptors of colorectal cancer and effective therapeutic targeting using biogenic silver nanoparticles

Increasing morbidity and mortality in CRC is a potential threat to human health. The major challenges for better treatment outcomes are the heterogeneity of CRC cases, complicated molecular pathway cross-talks, the influence of gut dysbiosis in CRC, and the lack of multimodal target-specific drug delivery. The overexpression of many receptors in CRC cells may pave the path for targeting them with multiple ligands. The design of a more target-specific drug-delivery device with multiple ligand-functionalized, green-synthesized silver nanoparticles is highly promising and may also deliver other approved chemotherapeutic agents. This review presents the various aspects of colorectal cancer and over-expressed receptors that can be targeted with appropriate ligands to enhance the specific drug delivery potency of green synthesised silver nanoparticles. This review aims to broaden further research into this multi-ligand functionalised, safer and effective silver nano drug delivery system.

Global biogeography and projection of antimicrobial toxin genes

BACKGROUND

Antimicrobial toxin genes (ATGs) encode potent antimicrobial weapons in nature that rival antibiotics, significantly impacting microbial survival and offering potential benefits for human health. However, the drivers of their global diversity and biogeography remain unknown.

RESULTS

Here, we identified 4400 ATG clusters from 149 families by correlating 10,000 samples worldwide with over 200,000 microbial genome data. We demonstrated that global microbial communities universally encode complex and diverse ATGs, with widespread differences across various habitats. Most ATG clusters were rare within habitats but were shared among habitats. Compared with those in animal-associated habitats, ATG clusters in human-associated habitats exhibit greater diversity and a greater proportion of sharing with natural habitats. We generated a global atlas of ATG distribution, identifying anthropogenic factors as crucial in explaining ATG diversity hotspots.

CONCLUSIONS

Our study provides baseline information on the global distribution of antimicrobial toxins by combining community samples, genome sequences, and environmental constraints. Our results highlight the natural environment as a reservoir of antimicrobial toxins, advance the understanding of the global distribution of these antimicrobial weapons, and aid their application in clinical, agricultural, and industrial fields. Video Abstract.

Bacterial small molecule metabolites implicated in gastrointestinal cancer development

Numerous associations have been identified between cancer and the composition and function of the human microbiome. As cancer remains the second leading global cause of mortality, investigating the carcinogenic contributions of microbiome members could advance our understanding of cancer risk and support potential therapeutic interventions. Although fluctuations in bacterial species have been associated with cancer progression, studying their small molecule metabolites offers one avenue to establish support for causal relationships and the molecular mechanisms governing host-microorganism interactions. In this Review, we explore the expanding repertoire of small molecule metabolites and their mechanisms implicated in the risk of developing gastrointestinal cancers.

Colibactin-induced damage in bacteria is cell contact independent

The bacterial toxin colibactin, produced primarily by the B2 phylogroup of Escherichia coli, underlies some cases of colorectal cancers. Colibactin crosslinks DNA and induces genotoxic damage in both mammalian and bacterial cells. While the mechanisms facilitating colibactin delivery remain unclear, results from multiple studies supported a delivery model that necessitates cell-cell contact. We directly tested this requirement in bacterial cultures by monitoring the spatiotemporal dynamics of the DNA damage response using a fluorescent transcriptional reporter. We found that in mixed-cell populations, DNA damage saturated within 12 hours and was detectable even in reporter cells separated from colibactin producers by hundreds of microns. Experiments with distinctly separated producer and reporter colonies revealed that the intensity of DNA damage decays similarly with distance regardless of colony contact. Our work reveals that cell contact is inconsequential for colibactin delivery in bacteria and suggests that contact dependence needs to be reexamined in mammalian cells as well.

IMPORTANCE

Colibactin is a bacteria-produced toxin that binds and damages DNA. It has been widely studied in mammalian cells due to its potential role in tumorigenesis. However, fundamental questions about its impact in bacteria remain underexplored. We used Escherichia coli as a model system to study colibactin toxicity in neighboring bacteria and directly tested if cell-cell contact is required for toxicity, as has previously been proposed. We found that colibactin can induce DNA damage in bacteria hundreds of microns away, and the intensity of DNA damage presents similarly regardless of cell-cell contact. Our work further suggests that the requirement for cell-cell contact for colibactin-induced toxicity also needs to be reevaluated in mammalian cells.

Cell free supernatants of Bifidobacterium adolescentis and Bifidobacterium longum suppress the tumor growth in colorectal cancer organoid model

The probiotic gut microbiome and its metabolites are pivotal in regulating host metabolism, inflammation, and immunity. Host genetics, colonization at birth, the host lifestyle, and exposure to diseases and drugs determine microbial composition. Dysbiosis and disruption of homeostasis in the beneficial microbiome have been reported to be involved in the tumorigenesis and progression of colorectal cancer (CRC). However, the influence of bacteria-secreted metabolites on CRC growth is yet to be fully elucidated. In this study, we compared the microbial composition of CRC patients to healthy controls to identify distinct patterns of microbiota-derived metabolites in CRC patients. Metagenomic analysis demonstrated that beneficial bacteria strains; Blautia producta, Bifidobacterium adolescentis, and Bifidobacterium longum decreased, while Parabacteroides distasonis and Bacteroides ovatus were more prevalent in the CRC patient group. Treatment of cancer organoid lines with microbial culture supernatants from Blautia producta, Bifidobacterium adolescentis, and Bifidobacterium longum showed remarkable inhibition of cancer growth. This study demonstrates that the bacterial metabolites depleted in CRC patients may inhibit cancer growth and highlights the effects of microbiome-derived metabolites on CRC growth.

Yatakemycin biosynthesis requires two deoxyribonucleases for toxin self-resistance

The highly active natural product yatakemycin (YTM) from Streptomyces sp. TP-A0356 is a potent DNA damaging agent with antimicrobial and antitumor properties. The YTM biosynthesis gene cluster (ytk) contains several toxin self-resistance genes. Of these, ytkR2 encodes a DNA glycosylase that is important for YTM production and host survival by excising lethal YTM-adenine lesions from the genome, presumably initiating a base excision repair (BER) pathway. However, the genes involved in repair of the resulting apurinic/apyrimidinic (AP) site as the second BER step have not been identified. Here, we show that ytkR4 and ytkR5 are essential for YTM production and encode deoxyribonucleases related to other known DNA repair nucleases. Purified YtkR4 and YtkR5 exhibit AP endonuclease activity specific for YtkR2-generated AP sites, providing a basis for BER of the toxic AP intermediate produced from YTM-adenine excision and consistent with co-evolution of ytkR2, ytkR4, and ytkR5. YtkR4 and YtkR5 also exhibit 3'-5' exonuclease activity with differing substrate specificities. The YtkR5 exonuclease is capable of digesting through a YTM-DNA lesion and may represent an alternative repair mechanism to BER. We also show that ytkR4 and ytkR5 homologs are often clustered together in putative gene clusters related to natural product production, consistent with non-redundant roles in repair of other DNA adducts derived from genotoxic natural products.

New Relevant Evidence in Cholangiocarcinoma Biology and Characterization

Among solid tumors, cholangiocarcinoma (CCA) emerges as one of the most difficult to eradicate. The silent and asymptomatic nature of this tumor, particularly in its early stages, as well as the high heterogeneity at genomic, epigenetic, and molecular levels delay the diagnosis, significantly compromising the efficacy of current therapeutic options and thus contributing to a dismal prognosis. Extensive research has been conducted on the molecular pathobiology of CCA, and recent advances have been made in the classification and characterization of new molecular targets. Both targeted therapy and immunotherapy have emerged as effective and safe strategies for various types of cancers, demonstrating potential benefits in advanced CCA. Furthermore, the deeper comprehension of the cellular and molecular components in the tumor microenvironment (TME) has opened up possibilities for new innovative treatment methods. This review discusses recent evidence in the characterization and molecular biology of CCA, highlighting novel possible druggable targets.

Study of Microbiota Associated to Early Tumors Can Shed Light on Colon Carcinogenesis

An increasingly important role for gut microbiota in the initiation and progression of colorectal cancer (CRC) has been described. Even in the early stages of transformation, i.e., colorectal adenomas, changes in gut microbiota composition have been observed, and several bacterial species, such as pks+Escherichia coli and enterotoxigenic Bacteroides fragilis, have been proposed to drive colon tumorigenesis. In recent years, several strategies have been developed to study mucosa-associated microbiota (MAM), which is more closely associated with CRC development than lumen-associated microbiota (LAM) derived from fecal samples. This review summarizes the state of the art about the oncogenic actions of gut bacteria and compares the different sampling strategies to collect intestinal microbiota (feces, biopsies, swabs, brushes, and washing aspirates). In particular, this article recapitulates the current knowledge on MAM in colorectal adenomas and serrated polyps, since studying the intestinal microbiota associated with early-stage tumors can elucidate the molecular mechanisms underpinning CRC carcinogenesis.

Identifications of the potential in-silico biomarkers in lung cancer tissue microbiomes

It is postulated that the tumor tissue microbiome is one of the enabling characteristics that can either promote or suppress the ability of tumors to acquire certain hallmarks of cancer. This underscores its critical importance in carcinogenesis, cancer progression, and therapy responses. However, characterizing the tumor microbiomes is extremely challenging because of their low biomass and severe difficulties in controlling laboratory-borne contaminants, which is further aggravated by lack of comprehensively effective computational approaches to identify unique or enriched microbial species associated with cancers. Here we take advantage of a recent computational framework by Ma (2024), termed metagenome comparison (MC) framework (MCF), which can detect treatment-specific, unique or enriched OMUs (operational metagenomic unit), or US/ES (unique/enriched species) when adapted for this study. We apply the MCF to reanalyze four lung cancer tissue microbiome datasets, which include samples from Lung Adenocarcinoma (LUAD), Lung Squamous Cell Carcinoma (LUSC), and their adjacent normal tissue (NT) controls. Our analysis is structured around three distinct schemes: Scheme I-separately detecting the US/ES for each of the four lung cancer microbiome datasets; Scheme II-consolidation of the four datasets followed by detection of US/ES in the combined datasets; Scheme III-construction of the union and intersection sets of US/ES derived from the results of the preceding two schemes. The generated lists of US/ES, including enriched microbial phyla, likely hold significant biomedical value for developing diagnostic and prognostic biomarkers for lung cancer risk assessment, improving the efficacy of immunotherapy, and designing novel microbiome-based therapies in lung cancer research.

Human intestinal microbiome: Role in health and disease

The study of the microbiota and the microbiome, and specifically the intestinal one, has determined great interest due to the possible association of their alterations with numerous diseases. These include entities as diverse as Crohn's disease, autism, diabetes, cancer or situations as prevalent today as obesity. In view of this situation, different recommendations have been performed regarding the use of probiotics, prebiotics, and postbiotics as modulators of the microbiota and the microbiome, seeking both preventive and therapeutic effects, and faecal material transfer (FMT) is proposed as an alternative. The latter has emerged as the only proven beneficial intervention on the intestinal microbiome, specifically in the treatment of recurrent colitis associated with Clostridioides difficile (R-CDI). In the rest of the entities, the lowering of laboratory costs has favored the study of the microbiome, which is resolved by delivering reports with catalogs of microorganisms, metabolites or supposed biomarkers without consensus on their composition associated with healthy or diseased microbiota and the disease. There is still insufficient evidence in any disease for interventions on the microbiome beyond FMT and R-CDI. Multi- and multi-disciplinary work with extensive research and the application of artificial intelligence in this field may shed light on the questions raised currently. Ethical issues must also be resolved in light of possible interventions within the umbrella of personalized medicine.

Microbiota in tumors: new factor influencing cancer development

Tumor microbiota research is a new field in oncology. With the advancement of high-throughput sequencing, there is growing evidence that a microbial community exists within tumor tissue. How these bacteria access tumor cells varies, including through the invasion of mucous membranes, the bloodstream, or the gut-organ axis. Previous literature has shown that microbes promote the development and progression of cancer through various mechanisms, such as affecting the host's immune system, promoting inflammation, regulating metabolism, and activating invasion and transfer. The study of the tumor microbiota offers a new perspective for the diagnosis and treatment of cancer, and it holds the potential for the development of new diagnostic tools and therapies. The role of the tumor microbiota in the pathogenesis of cancer is becoming increasingly evident, and future research will continue to uncover the specific mechanisms of action of these microbes, potentially shedding light on new strategies and methods for cancer prevention and therapy. This article reviews the latest advancements in this field, including how intratumor microbes migrate, their carcinogenic mechanisms, and the characteristics of different types of tumor microbes as well as the application of relevant methods in tumor microbiota research and the clinical values of targeting tumor microbes in cancer therapy.

Using New Technologies to Analyze Gut Microbiota and Predict Cancer Risk

The gut microbiota significantly impacts human health, influencing metabolism, immunological responses, and disease prevention. Dysbiosis, or microbial imbalance, is linked to various diseases, including cancer. It is crucial to preserve a healthy microbiome since pathogenic bacteria, such as Escherichia coli and Fusobacterium nucleatum, can cause inflammation and cancer. These pathways can lead to the formation of tumors. Recent advancements in high-throughput sequencing, metagenomics, and machine learning have revolutionized our understanding of the role of gut microbiota in cancer risk prediction. Early detection is made easier by machine learning algorithms that improve the categorization of cancer kinds based on microbiological data. Additionally, the investigation of the microbiome has been transformed by next-generation sequencing (NGS), which has made it possible to fully profile both cultivable and non-cultivable bacteria and to understand their roles in connection with cancer. Among the uses of NGS are the detection of microbial fingerprints connected to treatment results and the investigation of metabolic pathways implicated in the development of cancer. The combination of NGS with machine learning opens up new possibilities for creating customized medicine by enabling the development of diagnostic tools and treatments that are specific to each patient's microbiome profile, even in the face of obstacles like data complexity. Multi-omics studies reveal microbial interactions, biomarkers for cancer detection, and gut microbiota's impact on cancer progression, underscoring the need for further research on microbiome-based cancer prevention and therapy.

Whole-Genome Sequencing of Invasive Neonatal Escherichia coli From Uppsala County, Sweden

BACKGROUND

This study sought to investigate associations between virulence factors and phylogeny in all neonatal Escherichia coli bloodstream infections from patients admitted to the neonatal intensive care unit at Uppsala University Hospital between 2005 and 2020.

METHODS

A total of 37 E. coli isolates from 32 neonates were whole-genome sequenced and analyzed for virulence factors related to extraintestinal E. coli; patient-related data were collected retrospectively from the medical records.

RESULTS

E. coli isolates that belong to phylogroup B2 were associated with mortality (odds ratio [OR], 26; P < .001), extreme prematurity with delivery before gestational week 28 (OR, 9; P < .05), and shock (OR, 9; P < .05) compared with isolates of non-B2 group. Female neonates were more often infected with isolates of phylogroup B2 E. coli compared with male neonates (OR, 7; P = .05). The identification of the genotoxin determinant clb coding for colibactin exhibited strong associations with mortality (OR, 67; P < .005), gestational age (OR, 18; P < .005), and shock (OR, 26; P < .005).

DISCUSSION

The study highlighted the correlation between neonatal E. coli bacteremia caused by phylogroup B2 and the role of colibactin. Results emphasize difference between male and female neonates in E. coli populations in bloodstream infections.

Comprehensive retrospect and future perspective on bacteriophage and cancer

BACKGROUND

Researchers gradually focus on the relationship between phage and cancer.

OBJECTIVE

To summarize the research hotspots and trends in the field of bacteriophage and cancer.

METHODS

The downloaded articles were searched from the Web of Science Core Collection database from January 2008 to June 2023. Bibliometric analysis was carried out through CiteSpace, including the analysis of cooperative networks (country/region, institution, and author), co-citations of references, and key words.Visual analysis of three topics, including gut phage, phage and bacteria, and phage and tumor, was conducted.

RESULTS

Overall, the United States and China have the most phage-related research. In terms of gut phage, the future research directions are "gut microbiome", "database" and "microbiota". The bursting citations explored the phage-dominated viral genome to discover its diversity and individual specificity and investigated associations among bacteriome, metabolome, and virome. In terms of phage and bacteria, "lipopolysaccharide" and "microbiota" are future research directions. Future research hotspots should mainly concentrate on the further exploration and application of phage properties. As for phages and tumors, the future research directions should be "colorectal cancer", "protein" and "phage therapy". Future directions are likely to focus on the research on phages in cancer mechanisms, cancer diagnosis, and cancer treatment combined with genetic engineering techniques.

CONCLUSION

Phage therapy would become a hot spot and research direction of tumor and phage research, and the relationship between phage and tumor, especially colorectal cancer (CRC), is expected to be further explored.

Multi-adductomics: Advancing mass spectrometry techniques for comprehensive exposome characterization

Adductomics, an emerging field within the 'omics sciences, focuses on the formation and prevalence of DNA, RNA, and protein adducts induced by endogenous and exogenous agents in biological systems. These modifications often result from exposure to environmental pollutants, dietary components, and xenobiotics, impacting cellular functions and potentially leading to diseases such as cancer. This review highlights advances in mass spectrometry (MS) that enhance the detection of these critical modifications and discusses current and emerging trends in adductomics, including developments in MS instrument use, screening techniques, and the study of various biomolecular modifications from mono-adducts to complex hybrid crosslinks between different types of biomolecules. The review also considers challenges, including the need for specialized MS spectra databases and multi-omics integration, while emphasizing techniques to distinguish between exogenous and endogenous modifications. The future of adductomics possesses significant potential for enhancing our understanding of health in relation to environmental exposures and precision medicine.

Crosstalk Between the Intratumoral Microbiota and the Tumor Microenvironment: New Frontiers in Solid Tumor Progression and Treatment

BACKGROUND

The microbiota plays a significant role in the tumor microenvironment, and its impact on tumor development and treatment outcome cannot be overlooked. Thus, it is essential to comprehend the interactions between the microbiota and the tumor microenvironment.

RECENT FINDINGS

With the advent of next-generation sequencing, microbiota research has advanced significantly in recent years. The interaction between the intratumoral microbiota and the tumor microenvironment is an emerging area of research that holds great promise for understanding and treating solid tumor progression. This crosstalk between the intratumoral microbiota and the tumor microenvironment is a complex process that involves a multitude of factors, including the immune system, cellular signaling pathways, and metabolic processes. The origin of the intratumoral microbiota differs between various solid tumor, and the quantity and diversity of intratumoral microbiota also fluctuate significantly within each solid tumor.

CONCLUSION

The aim of this review is to provide a detailed summary of the intratumoral microbiota in various types of solid tumors. This will include an analysis of their origins, differences, and how they impact the progression of solid tumors. Furthermore, we will emphasize the significant potential that the intratumoral microbiota holds for the diagnosis and treatment of solid tumors.

Tumor Biology Hides Novel Therapeutic Approaches to Diffuse Large B-Cell Lymphoma: A Narrative Review

Diffuse large B-cell lymphoma (DLBCL) is a malignancy of immense biological and clinical heterogeneity. Based on the transcriptomic or genomic approach, several different classification schemes have evolved over the years to subdivide DLBCL into clinically (prognostically) relevant subsets, but each leaves unclassified samples. Herein, we outline the DLBCL tumor biology behind the actual and potential drug targets and address the challenges and drawbacks coupled with their (potential) use. Therapeutic modalities are discussed, including small-molecule inhibitors, naked antibodies, antibody-drug conjugates, chimeric antigen receptors, bispecific antibodies and T-cell engagers, and immune checkpoint inhibitors. Candidate drugs explored in ongoing clinical trials are coupled with diverse toxicity issues and refractoriness to drugs. According to the literature on DLBCL, the promise for new therapeutic targets lies in epigenetic alterations, B-cell receptor and NF-κB pathways. Herein, we present putative targets hiding in lipid pathways, ferroptosis, and the gut microbiome that could be used in addition to immuno-chemotherapy to improve the general health status of DLBCL patients, thus increasing the chance of being cured. It may be time to devote more effort to exploring DLBCL metabolism to discover novel druggable targets. We also performed a bibliometric and knowledge-map analysis of the literature on DLBCL published from 2014-2023.

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.

Signaling pathways involved in colorectal cancer: pathogenesis and targeted therapy

Colorectal cancer (CRC) remains one of the leading causes of cancer-related mortality worldwide. Its complexity is influenced by various signal transduction networks that govern cellular proliferation, survival, differentiation, and apoptosis. The pathogenesis of CRC is a testament to the dysregulation of these signaling cascades, which culminates in the malignant transformation of colonic epithelium. This review aims to dissect the foundational signaling mechanisms implicated in CRC, to elucidate the generalized principles underpinning neoplastic evolution and progression. We discuss the molecular hallmarks of CRC, including the genomic, epigenomic and microbial features of CRC to highlight the role of signal transduction in the orchestration of the tumorigenic process. Concurrently, we review the advent of targeted and immune therapies in CRC, assessing their impact on the current clinical landscape. The development of these therapies has been informed by a deepening understanding of oncogenic signaling, leading to the identification of key nodes within these networks that can be exploited pharmacologically. Furthermore, we explore the potential of integrating AI to enhance the precision of therapeutic targeting and patient stratification, emphasizing their role in personalized medicine. In summary, our review captures the dynamic interplay between aberrant signaling in CRC pathogenesis and the concerted efforts to counteract these changes through targeted therapeutic strategies, ultimately aiming to pave the way for improved prognosis and personalized treatment modalities in colorectal cancer.

Total Synthesis of (±)-3-Thiaglutamate

The total synthesis of (±)-3-thiaglutamate is reported. Central to our strategy is an thiol addition to an imine to form the thioaminal of the natural product. The resulting thioaminal product is then subjected to triflic acid global deprotection to produce 3-thiaglutamate as a triflate salt. This work constitutes the first total synthesis of 3-thiaglutamate and demonstrates that the hemithioaminal group in 3-thiaglutamate can be stabilized under acidic conditions.

Beyond the Gut: The intratumoral microbiome's influence on tumorigenesis and treatment response

The intratumoral microbiome (TM) refers to the microorganisms in the tumor tissues, including bacteria, fungi, viruses, and so on, and is distinct from the gut microbiome and circulating microbiota. TM is strongly associated with tumorigenesis, progression, metastasis, and response to therapy. This paper highlights the current status of TM. Tract sources, adjacent normal tissue, circulatory system, and concomitant tumor co-metastasis are the main origin of TM. The advanced techniques in TM analysis are comprehensively summarized. Besides, TM is involved in tumor progression through several mechanisms, including DNA damage, activation of oncogenic signaling pathways (phosphoinositide 3-kinase [PI3K], signal transducer and activator of transcription [STAT], WNT/β-catenin, and extracellular regulated protein kinases [ERK]), influence of cytokines and induce inflammatory responses, and interaction with the tumor microenvironment (anti-tumor immunity, pro-tumor immunity, and microbial-derived metabolites). Moreover, promising directions of TM in tumor therapy include immunotherapy, chemotherapy, radiotherapy, the application of probiotics/prebiotics/synbiotics, fecal microbiome transplantation, engineered microbiota, phage therapy, and oncolytic virus therapy. The inherent challenges of clinical application are also summarized. This review provides a comprehensive landscape for analyzing TM, especially the TM-related mechanisms and TM-based treatment in cancer.

Escherichia coli on colorectal cancer: A two-edged sword

Escherichia coli (E. coli) is a ubiquitous symbiotic bacterium in the gut, and the diversity of E. coli genes determines the diversity of its functions. In this review, the two-edged sword theory was innovatively proposed. For the question 'how can we harness the ambivalent nature of E. coli to screen and treat CRC?', in terms of CRC screening, the variations in the abundance and subtypes of E. coli across different populations present an opportunity to utilise it as a biomarker, while in terms of CRC treatment, the natural beneficial effect of E. coli on CRC may be limited, and engineered E. coli, particularly certain subtypes with probiotic potential, can indeed play a significant role in CRC treatment. It seems that the favourable role of E. coli as a genetic tool lies not in its direct impact on CRC but its potential as a research platform that can be integrated with various technologies such as nanoparticles, imaging methods, and synthetic biology modification. The relationship between gut microflora and CRC remains unclear due to the complex diversity and interaction of gut microflora. Therefore, the application of E. coli should be based on the 'One Health' view and take the interactions between E. coli and other microorganisms, host, and environmental factors, as well as its own changes into account. In this paper, the two-edged sword role of E. coli in CRC is emphasised to realise the great potential of E. coli in CRC screening and treatment.

Gut bacteria, host immunity, and colorectal cancer: From pathogenesis to therapy

The emergence of 16S rRNA and metagenomic sequencing has gradually revealed the close relationship between dysbiosis and colorectal cancer (CRC). Recent studies have confirmed that intestinal dysbiosis plays various roles in the occurrence, development, and therapeutic response of CRC. Perturbation of host immunity is one of the key mechanisms involved. The intestinal microbiota, or specific bacteria and their metabolites, can modulate the progression of CRC through pathogen recognition receptor signaling or via the recruitment, polarization, and activation of both innate and adaptive immune cells to reshape the protumor/antitumor microenvironment. Therefore, the administration of gut bacteria to enhance immune homeostasis represents a new strategy for the treatment of CRC. In this review, we cover recent studies that illuminate the role of gut bacteria in the progression and treatment of CRC through orchestrating the immune response, which potentially offers insights for subsequent transformative research.

Elucidating the genotoxicity of Fusobacterium nucleatum-secreted mutagens in colorectal cancer carcinogenesis

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) is one of the key tumorigenic bacteria in colorectal cancer (CRC), yet how F. nucleatum is involved in colorectal cancer carcinogenesis remains unknown.

RESULTS

In the present study, we carried out PathSeq analysis on RNA sequencing data from the 430 primary colon adenocarcinomas in TCGA database to assess the relationship between patients' survival and F. nucleatum abundance. Among patients with cecum and ascending colon tumors, we found that F. nucleatum transcriptome abundance is positively correlated with mutation load. We further demonstrated that patients with both high tumoral abundance of F. nucleatum and high mutation load exhibited poorer survival and DNA damage. We furthermore determined that F. nucleatum-conditioned medium (Fn. CM) induces DNA damage in both in vitro and in vivo studies. In addition, two F. nucleatum-secreted mutagens, namely DL-homocystine and allantoic acid, were identified to lead to DNA damage.

CONCLUSIONS

Our finding delineates the genotoxicity of F.nucleatum-secreted mutagens, which provides a basis for further work to investigate the role of F. nucleatum in the pathogenicity of CRC.

Intratumoral microbiota as a novel prognostic indicator in bladder cancer

Microbes are important components of the tumor microenvironment and have a close relationship with tumors. However, there is still a lack of research on the intratumoral microbiota in bladder cancer and its impact on the tumor immune microenvironment. In this study, we used fluorescence in situ hybridization (FISH) and observed a substantial presence of microbiota in bladder cancer tissues, with greater abundance compared to that in normal bladder tissues. Based on the BIC database, we found that the microbiome of bladder cancer is highly diverse and its structure is significantly different from that of other tumors. To investigate the relationships among the intratumoral microbiota, tumor immunity, and prognosis in bladder cancer patients, we analyzed bladder cancer-specific differentially expressed immune- and antimicrobial-related genes from the ImmPort, TISIDB, and TCGA databases. We identified 11 hub genes and constructed a prognostic risk model. Further analysis revealed differences at the family and genus levels between distinct groups. Using LEfSe analysis, we identified six hub biomarkers and developed a novel microbial-based scoring system. The scoring system allows subgrouping of bladder cancer patients, with significant differences in prognosis, immune cell infiltration, tumor mutation burden, and immune checkpoints among different groups. Further FISH and immunofluorescence co-staining experiments initially verified that the specific distribution of microorganisms and M2 macrophages in bladder cancer may be closely related to the poor prognosis of patients. In conclusion, this study revealed the characteristics of the intratumoral microbiota in bladder cancer and identified potential prognostic targets for clinical application.

Colibactin leads to a bacteria-specific mutation pattern and self-inflicted DNA damage

Colibactin produced primarily by Escherichia coli strains of the B2 phylogroup cross-links DNA and can promote colon cancer in human hosts. Here, we investigate the toxin's impact on colibactin producers and on bacteria cocultured with producing cells. Using genome-wide genetic screens and mutation accumulation experiments, we uncover the cellular pathways that mitigate colibactin damage and reveal the specific mutations it induces. We discover that although colibactin targets A/T-rich motifs, as observed in human colon cells, it induces a bacteria-unique mutation pattern. Based on this pattern, we predict that long-term colibactin exposure will culminate in a genomic bias in trinucleotide composition. We test this prediction by analyzing thousands of E. coli genomes and find that colibactin-producing strains indeed show the predicted skewness in trinucleotide composition. Our work reveals a bacteria-specific mutation pattern and suggests that the resistance protein encoded on the colibactin pathogenicity island is insufficient in preventing self-inflicted DNA damage.

DNA Adductomics: A Narrative Review of Its Development, Applications, and Future

DNA adductomics is the global study of all DNA adducts and was first proposed in 2006 by the Matsuda group. Its development has been greatly credited to the advances in mass spectrometric techniques, particularly tandem and multiple-stage mass spectrometry. In fact, liquid chromatography-mass spectrometry (LC-MS)-based methods are virtually the sole technique with practicality for DNA adductomic studies to date. At present, DNA adductomics is primarily used as a tool to search for DNA adducts, known and unknown, providing evidence for exposure to exogenous genotoxins and/or for the molecular mechanisms of their genotoxicity. Some DNA adducts discovered in this way have the potential to predict cancer risks and/or to be associated with adverse health outcomes. DNA adductomics has been successfully used to identify and determine exogenous carcinogens that may contribute to the etiology of certain cancers, including bacterial genotoxins and an N-nitrosamine. Also using the DNA adductomic approach, multiple DNA adducts have been observed to show age dependence and may serve as aging biomarkers. These achievements highlight the capability and power of DNA adductomics in the studies of medicine, biological science, and environmental science. Nonetheless, DNA adductomics is still in its infancy, and great advances are expected in the future.

Microbial genotoxin-elicited host DNA mutations related to mitochondrial dysfunction, a momentous contributor for colorectal carcinogenesis

Gut microbe dysbiosis increases repetitive inflammatory responses, leading to an increase in the incidence of colorectal cancer. Recent studies have revealed that specific microbial species directly instigate mutations in the host nucleus DNA, thereby accelerating the progression of colorectal cancer. Given the well-established role of mitochondrial dysfunction in promoting colorectal cancer, it is reasonable to postulate that gut microbes may induce mitochondrial gene mutations, thereby inducing mitochondrial dysfunction. In this review, we focus on gut microbial genotoxins and their known and potential targets in mitochondrial genes. Consequently, we propose that targeted disruption of genotoxin transport pathways may effectively reduce the rate of mitochondrial gene mutations and yield substantial benefits for the prevention of colorectal carcinogenesis.

An expanded database and analytical toolkit for identifying bacterial virulence factors and their associations with chronic diseases

Virulence factor genes (VFGs) play pivotal roles in bacterial infections and have been identified within the human gut microbiota. However, their involvement in chronic diseases remains poorly understood. Here, we establish an expanded VFG database (VFDB 2.0) consisting of 62,332 nonredundant orthologues and alleles of VFGs using species-specific average nucleotide identity ( https://github.com/Wanting-Dong/MetaVF_toolkit/tree/main/databases ). We further develop the MetaVF toolkit, facilitating the precise identification of pathobiont-carried VFGs at the species level. A thorough characterization of VFGs for 5452 commensal isolates from healthy individuals reveals that only 11 of 301 species harbour these factors. Further analyses of VFGs within the gut microbiomes of nine chronic diseases reveal both common and disease-specific VFG features. Notably, in type 2 diabetes patients, long HiFi sequencing confirms that shared VF features are carried by pathobiont strains of Escherichia coli and Klebsiella pneumoniae. These findings underscore the critical importance of identifying and understanding VFGs in microbiome-associated diseases.

Pharmacomicrobiomics in precision cancer therapy: bench to bedside

The burgeoning field of pharmacomicrobiomics offers promising insights into the intricate interplay between the microbiome and cancer, shaping responses to diverse treatment modalities. This review aims to analyze the molecular mechanisms underlying interactions between distinct microbiota types and cancer, as well as their influence on treatment outcomes. We explore how the microbiome impacts antitumor immunity, and response to chemotherapy, immunotherapy, and radiation therapy, unveiling its multifaceted roles in cancer progression and therapy resistance. Moreover, we discuss the challenges hindering the development of microbiome-based interventions in cancer therapy, including standardization, validation, and clinical translation. By synthesizing clinical evidence, we underscore the transformative potential of harnessing pharmacomicrobiomics in guiding cancer treatment decisions, paving the way for improved patient outcomes in clinical practice.