Fusobacterium nucleatum in colorectal carcinoma tissue and patient prognosis

Implications of Gut Microbiota in Epithelial-Mesenchymal Transition and Cancer Progression: A Concise Review

Advancement in the development of molecular sequencing platforms has identified infectious bacteria or viruses that trigger the dysregulation of a set of genes inducing the epithelial-mesenchymal transition (EMT) event. EMT is essential for embryogenesis, wound repair, and organ development; meanwhile, during carcinogenesis, initiation of the EMT can promote cancer progression and metastasis. Recent studies have reported that interactions between the host and dysbiotic microbiota in different tissues and organs, such as the oral and nasal cavities, esophagus, stomach, gut, skin, and the reproductive tract, may provoke EMT. On the other hand, it is revealed that certain microorganisms display a protective role against cancer growth, indicative of possible therapeutic function. In this review, we summarize recent findings elucidating the underlying mechanisms of pathogenic microorganisms, especially the microbiota, in eliciting crucial regulator genes that induce EMT. Such an approach may help explain cancer progression and pave the way for developing novel preventive and therapeutic strategies.

The Emerging Roles of Human Gut Microbiota in Gastrointestinal Cancer

The gut microbiota is composed of a large number of microorganisms with a complex structure. It participates in the decomposition, digestion, and absorption of nutrients; promotes the development of the immune system; inhibits the colonization of pathogens; and thus modulates human health. In particular, the relationship between gut microbiota and gastrointestinal tumor progression has attracted widespread concern. It was found that the gut microbiota can influence gastrointestinal tumor progression in independent ways. Here, we focused on the distribution of gut microbiota in gastrointestinal tumors and further elaborated on the impact of gut microbiota metabolites, especially short-chain fatty acids, on colorectal cancer progression. Additionally, the effects of gut microbiota on gastrointestinal tumor therapy are outlined. Finally, we put forward the possible problems in gut microbiota and the gastrointestinal oncology field and the efforts we need to make.

Nutrition-wide association study of microbiome diversity and composition in colorectal cancer patients

BACKGROUND

The effects of diet on the interaction between microbes and host health have been widely studied. However, its effects on the gut microbiota of patients with colorectal cancer (CRC) have not been elucidated. This study aimed to investigate the association between diet and the overall diversity and different taxa levels of the gut microbiota in CRC patients via the nutrition-wide association approach.

METHODS

This hospital-based study utilized data of 115 CRC patients who underwent CRC surgery in Department of Surgery, Seoul National University Hospital. Spearman correlation analyses were conducted for 216 dietary features and three alpha-diversity indices, Firmicutes/Bacteroidetes ratio, and relative abundance of 439 gut microbial taxonomy. To identify main enterotypes of the gut microbiota, we performed the principal coordinate analysis based on the β-diversity index. Finally, we performed linear regression to examine the association between dietary intake and main microbiome features, and linear discriminant analysis effect size (LEfSe) to identify bacterial taxa phylogenetically enriched in the low and high diet consumption groups.

RESULTS

Several bacteria were enriched in patients with higher consumption of mature pumpkin/pumpkin juice (ρ, 0.31 to 0.41) but lower intake of eggs (ρ, -0.32 to -0.26). We observed negative correlations between Bacteroides fragilis abundance and intake of pork (belly), beef soup with vegetables, animal fat, and fatty acids (ρ, -0.34 to -0.27); an inverse correlation was also observed between Clostridium symbiosum abundance and intake of some fatty acids, amines, and amino acids (ρ, -0.30 to -0.24). Furthermore, high intake of seaweed was associated with a 6% (95% CI, 2% to 11%) and 7% (95% CI, 2% to 11%) lower abundance of Rikenellaceae and Alistipes, respectively, whereas overall beverage consumption was associated with an 10% (95% CI, 2% to 18%) higher abundance of Bacteroidetes, Bacteroidia, and Bacteroidales, compared to that in the low intake group. LEfSe analysis identified phylogenetically enriched taxa associated with the intake of sugars and sweets, legumes, mushrooms, eggs, oils and fats, plant fat, carbohydrates, and monounsaturated fatty acids.

CONCLUSIONS

Our data elucidates the diet-microbe interactions in CRC patients. Additional research is needed to understand the significance of these results in CRC prognosis.

The vaginal microbiome is associated with endometrial cancer grade and histology

The human microbiome has been strongly correlated with disease pathology and outcomes, yet remains relatively underexplored in patients with malignant endometrial disease. In this study, vaginal microbiome samples were prospectively collected at the time of hysterectomy from 61 racially and ethnically diverse patients from three disease conditions: 1) benign gynecologic disease (controls, n=11), 2) low-grade endometrial carcinoma (n=30), and 3) high-grade endometrial carcinoma (n=20). Extracted DNA underwent shotgun metagenomics sequencing, and microbial α and β diversities were calculated. Hierarchical clustering was used to describe community state types (CST), which were then compared by microbial diversity and grade. Differential abundance was calculated, and machine learning utilized to assess the predictive value of bacterial abundance to distinguish grade and histology. Both α- and β-diversity were associated with patient tumor grade. Four vaginal CST were identified that associated with grade of disease. Different histologies also demonstrated variation in CST within tumor grades. Using supervised clustering algorithms, critical microbiome markers at the species level were used to build models that predicted benign vs carcinoma, high-grade carcinoma versus benign, and high-grade versus low-grade carcinoma with high accuracy. These results confirm that the vaginal microbiome segregates not just benign disease from endometrial cancer, but is predictive of histology and grade. Further characterization of these findings in large, prospective studies is needed to elucidate their potential clinical applications.

The respiratory microbiome associated with chronic obstructive pulmonary disease comorbidity in non-small cell lung cancer

Background

Research has shown that some microbiomes are linked to cancer. Hence, we hypothesize that alterations in the respiratory microbiome might be associated with lung cancer.

Methods

Through droplet digital polymerase chain reaction analysis, we investigated the abundance of Acidovorax in surgically resected primary tumors and corresponding nontumor lung tissues obtained from 50 Japanese patients with non‐small cell lung cancer.

Results

The rate of positivity for Acidovorax in tumor and nontumor tissues was 44 and 26%, respectively. The abundance of Acidovorax in tumor tissues was significantly higher in patients with nonsquamous cell carcinoma complicated by chronic obstructive pulmonary disease (COPD) and those who relapsed after surgical resection (p < 0.05). In tumor tissues, the results of the univariate and multivariate analyses revealed that only COPD exerted a direct effect on the abundance of Acidovorax (p < 0.05). Furthermore, the presence of Acidovorax was high in lung cancer patients with COPD comorbidity (65%) and TP53 gene mutation; only one of the nontumor tissues was positive for Acidovorax. In patients with lung cancer complicated by COPD, Acidovorax tended to be present in both the tumor and nontumor areas.

Conclusions

This study identified novel microbiota involved in lung cancer with COPD comorbidity. The results suggested that Acidovorax may be a useful biomarker in the screening for lung cancer. Further studies are warranted to validate the clinical significance of the microbiome in a larger independent patient cohort.

Gut mucosal microbiota profiles linked to colorectal cancer recurrence

BACKGROUND

Emerging evidence links gut microbiota to various human diseases including colorectal cancer (CRC) initiation and development. However, gut microbiota profiles associated with CRC recurrence and patient prognosis are not completely understood yet, especially in a Chinese cohort.

AIM

To investigate the relationship between gut mucosal microbiota profiles and CRC recurrence and patient prognosis.

METHODS

We obtained the composition and structure of gut microbiota collected from 75 patients diagnosed with CRC and 26 healthy controls. The patients were followed up by regular examination to determine whether tumors recurred. Triplet-paired samples from on-tumor, adjacent-tumor and off-tumor sites of patients diagnosed with/without CRC recurrence were analyzed to assess spatial-specific patterns of gut mucosal microbiota by 16S ribosomal RNA sequencing. Next, we carried out bioinformatic analyses, Kaplan-Meier survival analyses and Cox regression analyses to determine the relationship between gut mucosal microbiota profiles and CRC recurrence and patient prognosis.

RESULTS

We observed spatial-specific patterns of gut mucosal microbiota profiles linked to CRC recurrence and patient prognosis. A total of 17 bacterial genera/families were identified as potential biomarkers for CRC recurrence and patient prognosis, including Anaerotruncus, Bacteroidales, Coriobacteriaceae, Dialister, Eubacterium, Fusobacterium, Filifactor, Gemella, Haemophilus, Mogibacteriazeae, Pyramidobacter, Parvimonas, Porphyromonadaceae, Slackia, Schwartzia, TG5 and Treponema.

CONCLUSION

Our work suggests that intestinal microbiota can serve as biomarkers to predict the risk of CRC recurrence and patient death.

Fusobacterium nucleatum promotes colon cancer progression by changing the mucosal microbiota and colon transcriptome in a mouse model

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) has long been known to cause opportunistic infections and has recently been implicated in colorectal cancer (CRC), which has attracted broad attention. However, the mechanism by which it is involved in CRC development is not fully understood.

AIM

To explore its potential causative role in CRC development, we evaluated the colon pathology, mucosa barrier, colon microbiota and host transcriptome profile after F. nucleatum infection in an azoxymethane/dextran sulfate sodium salt (AOM/DSS) mouse model.

METHODS

Three groups of mice were compared to reveal the differences, i.e., the control, AOM/DSS-induced CRC and AOM/DSS-FUSO infection groups.

RESULTS

Both the AOM/DSS and AOM/DSS-FUSO groups exhibited a significantly reduced body weight and increased tumor numbers than the control group, and AOM/DSS mice with F. nucleatum infection showed the highest tumor formation ratio among the three groups. Moreover, the colon pathology was the most serious in the AOM/DSS-FUSO group. We found that the structure of the colon microbiota changed considerably after F. nucleatum infection; striking differences in mucosal microbial population patterns were observed between the AOM/DSS-FUSO and AOM/DSS groups, and inflammation-inducing bacteria were enriched in the mucosal microbiota in the AOM/DSS-FUSO group. By comparing intestinal transcriptomics data from AOM vs AOM/DSS-FUSO mice, we showed that transcriptional activity was strongly affected by dysbiosis of the gut microbiota. The most microbiota-sensitive genes were oncogenes in the intestine, and the cyclic adenosine monophosphate signaling pathway, neuroactive ligand–receptor interaction, PPAR signaling pathway, retinol metabolism, mineral absorption and drug metabolism were highly enriched in the AOM/DSS-FUSO group. Additionally, we showed that microbial dysbiosis driven by F. nucleatum infection enriched eight taxa belonging to Proteobacteria, which correlates with increased expression of oncogenic genes.

CONCLUSION

Our study demonstrated that F. nucleatum infection altered the colon mucosal microbiota by enriching pathogens related to the development of CRC, providing new insights into the role of F. nucleatum in the oncogenic microbial environment of the colon.

Fusobacterium nucleatum: a new player in regulation of cancer development and therapeutic response

A dysbiosis in microbial diversity or functionality can promote disease development. Emerging preclinical and clinical evidence emphasizes the interplay between microbiota and both disease evolution and the treatment response of different cancers. One bacterium that has garnered much attention in a few cancer microbiota studies is Fusobacterium nucleaum (Fn). To provide updated knowledge of the functional role of Fn in cancer prevention and management, this review summarizes the relationship among Fn, cancer, and chemoimmunotherapy response, with the potential mechanisms of action also intensively discussed, which will benefit the development of strategies to prevent or treat cancer via Fn-based therapeutic interventions.

Fusobacterium nucleatum promotes colorectal cancer cells adhesion to endothelial cells and facilitates extravasation and metastasis by inducing ALPK1/NF-κB/ICAM1 axis

Metastasis is the leading cause of death for colorectal cancer (CRC) patients, and the spreading tumor cells adhesion to endothelial cells is a critical step for extravasation and further distant metastasis. Previous studies have documented the important roles of gut microbiota-host interactions in the CRC malignancy, and Fusobacterium nucleatum (F. nucleatum) was reported to increase proliferation and invasive activities of CRC cells. However, the potential functions and underlying mechanisms of F. nucleatum in the interactions between CRC cells and endothelial cells and subsequent extravasation remain unclear. Here, we uncovered that F. nucleatum enhanced the adhesion of CRC cells to endothelial cells, promoted extravasation and metastasis by inducing ICAM1 expression. Mechanistically, we identified that F. nucleatum induced a new pattern recognition receptor ALPK1 to activate NF-κB pathway, resulting in the upregulation of ICAM1. Interestingly, the abundance of F. nucleatum in tumor tissues of CRC patients was positively associated with the expression levels of ALPK1 and ICAM1. Moreover, high expression of ALPK1 or ICAM1 was significantly associated with a shorter overall survival time of CRC patients. This study provides a new insight into the role of gut microbiota in engaging into the distant metastasis of CRC cells.

A Disintegrin and Metalloproteinase (ADAM) Family-Novel Biomarkers of Selected Gastrointestinal (GI) Malignancies?

The global burden of gastrointestinal (GI) cancers is expected to increase. Therefore, it is vital that novel biomarkers useful for the early diagnosis of these malignancies are established. A growing body of data has linked secretion of proteolytic enzymes, such as metalloproteinases (MMPs), which destroy the extracellular matrix, to pathogenesis of GI tumours. A disintegrin and metalloproteinase (ADAM) proteins belong to the MMP family but have been proven to be unique due to both proteolytic and adhesive properties. Recent investigations have demonstrated that the expression of several ADAMs is upregulated in GI cancer cells. Thus, the objective of this review is to present current findings concerning the role of ADAMs in the pathogenesis of GI cancers, particularly their involvement in the development and progression of colorectal, pancreatic and gastric cancer. Furthermore, the prognostic significance of selected ADAMs in patients with GI tumours is also presented. It has been proven that ADAM8, 9, 10, 12, 15, 17 and 28 might stimulate the proliferation and invasion of GI malignancies and may be associated with unfavourable survival. In conclusion, this review confirms the role of selected ADAMs in the pathogenesis of the most common GI cancers and indicates their promising significance as potential prognostic biomarkers as well as therapeutic targets for GI malignancies. However, due to their non-specific nature, future research on ADAM biology should be performed to elucidate new strategies for the diagnosis of these common and deadly malignancies and treatment of patients with these diseases.

A systematic review of microbial markers for risk prediction of colorectal neoplasia

BACKGROUND

Substantial evidence indicates that dysbiosis of the gut microbial community is associated with colorectal neoplasia. This review aims to systematically summarise the microbial markers associated with colorectal neoplasia and to assess their predictive performance.

METHODS

A comprehensive literature search of MEDLINE and EMBASE databases was performed to identify eligible studies. Observational studies exploring the associations between microbial biomarkers and colorectal neoplasia were included. We also included prediction studies that constructed models using microbial markers to predict CRC and adenomas. Risk of bias for included observational and prediction studies was assessed.

RESULTS

Forty-five studies were included to assess the associations between microbial markers and colorectal neoplasia. Nine faecal microbiotas (i.e., Fusobacterium, Enterococcus, Porphyromonas, Salmonella, Pseudomonas, Peptostreptococcus, Actinomyces, Bifidobacterium and Roseburia), two oral pathogens (i.e., Treponema denticola and Prevotella intermedia) and serum antibody levels response to Streptococcus gallolyticus subspecies gallolyticus were found to be consistently associated with colorectal neoplasia. Thirty studies reported prediction models using microbial markers, and 83.3% of these models had acceptable-to-good discrimination (AUROC > 0.75). The results of predictive performance were promising, but most of the studies were limited to small number of cases (range: 9-485 cases) and lack of independent external validation (76.7%).

CONCLUSIONS

This review provides insight into the evidence supporting the association between different types of microbial species and their predictive value for colorectal neoplasia. Prediction models developed from case-control studies require further external validation in high-quality prospective studies. Further studies should assess the feasibility and impact of incorporating microbial biomarkers in CRC screening programme.

Salivary Fusobacterium nucleatum serves as a potential biomarker for colorectal cancer

Fusobacterium nucleatum (Fn) is primarily colonized in the oral cavity. Recently, Fn has been closely associated with the tumorigenesis of colorectal cancer (CRC). Here, we showed that the relative level of Fn DNA was increased in the saliva of the CRC group compared with the normal colonoscopy, hyperplastic polyp, and adenoma groups. Receiver operating characteristic curve analysis illustrated that Fn DNA was superior to carcinoembryonic antigen and carbohydrate antigen 19-9 in CRC diagnosis. Moreover, levels of Fn DNA were associated with the overall survival and disease-free survival of CRC patients, which was an independent factor for prognostic prediction. Transcriptome sequencing identified 1,287 differentially expressed mRNAs in tumor tissues between CRC patients with high-Fn and low-Fn infection. Kyoto encyclopedia of genes and genomes analysis showed that ECM-receptor interaction and focal adhesion were the top two significant pathways. Overall, salivary Fn DNA may be a noninvasive diagnostic and prognostic biomarker for CRC patients.

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Fusobacterium nucleatum DNA level is increased in saliva of colorectal cancer patients

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Salivary F. nucleatum DNA is a biomarker for colorectal cancer diagnosis

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Salivary F. nucleatum DNA is an independent prognostic factor

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KEGG identified relationships to ECM-receptor interaction and focal adhesion pathways

The association between Fusobacterium nucleatum and cancer colorectal: A systematic review and meta-analysis

INTRODUCTION

The etiological factors of colorectal cancer (CRC) are not precisely known, although genetic and environmental factors have been implicated. A possible association with Fusobacterium nucleatum may provide opportunities for an early diagnosis.

OBJECTIVE

To review studies that address the association between F. nucleatum and CRC.

METHODS

The MEDLINE PubMed database was searched using the terms «colorectal cancer» and "Fusobacterium nucleatum", retrieving publications published up to January 1 2020. Stata software was used for a meta-analysis.

RESULTS

The systematic review included 57 articles. Meta-analysis results indicated a more frequent presence of F. nucleatum in CRC tumour tissue samples in comparison to control samples of healthy tissue, with an odds ratio of 4.558 (95% CI: 3.312-6.272), and in comparison, to control samples of colorectal adenomas, with an odds ratio of 3.244 (95 % CI: 2.359-4.462).

CONCLUSION

There is a more frequent resence of F. nucleatum in the CRC. However, further studies are needed to verify this relationship.

Biomarkers of Response and Resistance to Immunotherapy in Microsatellite Stable Colorectal Cancer: Toward a New Personalized Medicine

Immune Checkpoint Inhibitors (ICIs) are well recognized as a major immune treatment modality for multiple types of solid cancers. However, for colorectal cancer (CRC), ICIs are only approved for the treatment of Mismatch-Repair-Deficient and Microsatellite Instability-High (dMMR/MSI-H) tumors. For the vast majority of CRC, that are not dMMR/MSI-H, ICIs alone provide limited to no clinical benefit. This discrepancy of response between CRC and other solid cancers suggests that CRC may be inherently resistant to ICIs alone. In translational research, efforts are underway to thoroughly characterize the immune microenvironment of CRC to better understand the mechanisms behind this resistance and to find new biomarkers of response. In the clinic, trials are being set up to study biomarkers along with treatments targeting newly discovered immune checkpoint molecules or treatments combining ICIs with other existing therapies to improve response in MSS CRC. In this review, we will focus on the characteristics of response and resistance to ICIs in CRC, and discuss promising biomarkers studied in recent clinical trials combining ICIs with other therapies.

The Need for Oral Hygiene Care and Periodontal Status among Hospitalized Gastric Cancer Patients

Poor oral hygiene leads to the accumulation of dental plaque, thus contributing to the initiation of periodontal disease (PD). Local infections can lead to systemic inflammatory responses, which are essential mediators for the evolution of systemic conditions or cancer tumorigenesis. Often, patients hospitalized with life-threatening and incapacitating disorders such as gastric cancer (GC) might lose interest in keeping their mouth healthy. This study evaluates oral hygiene, periodontal status, and the need for oral care and medical personnel to assist in achieving it in patients hospitalized with GC. This study was carried out on 25 patients with a diagnosis of GC, divided into two groups (GP-14 patients from the Gastroenterology Department, and SP-11 patients from the 1st Department of Surgery). Patients were examined on the day of admission (T0), the day of the medical procedure of endoscopy or surgery (T1), and the day of discharge (T2), recording the number of absent teeth, dental plaque (PI), bleeding on probing (BOP), probing depths (PPD), frequency of toothbrushing, and if the oral hygiene had been self-performed or assisted. Data were subjected to statistical analysis. Our results showed that, in both the GP and the SP group, there were strong and statistically significant correlations between PI and BOP measured on the last day of hospitalization and the period of hospitalization after the medical procedure. Longer hospital stays and the presence of surgery were risk factors for changing toothbrushing frequency. Results also highlight the need for a dentist to diagnose and eventually treat periodontal disease before and after hospitalization, and for a trained nurse who should help take care of the patient's oral hygiene during hospitalization.

Role of CD155/TIGIT in Digestive Cancers: Promising Cancer Target for Immunotherapy

The tumor microenvironment restricts the function and survival of various immune cells by up-regulating inhibitory immune checkpoints, and participates in the immune escape of tumors. The development of immunotherapies targeting immune checkpoints, such as programmed cell death receptor 1 antibody and anti-cytotoxic T lymphocyte-associated antigen 4 antibody, has provided many options for cancer treatment. The efficacy of other immune checkpoint inhibitors is also under development and research. Among them, T cell immunoreceptor with Ig and ITIM domains (TIGIT) has shown excellent clinical application prospects. Correspondingly, poliovirus receptor (PVR, CD155), one of the main ligands of TIGIT, is mainly expressed in various human malignant tumors and myeloid cells. CD155 interacts with TIGIT on natural killer cells and T cells, mediating inhibitory immunomodulatory regulation. This study summarized the mechanism of CD155/TIGIT in regulating immune cells and its role in the occurrence and development of digestive system tumors, aiming to provide a new perspective for immunotherapy of digestive cancers.

Diversity and distribution of sulfur metabolic genes in the human gut microbiome and their association with colorectal cancer

BACKGROUND

Recent evidence implicates microbial sulfidogenesis as a potential trigger of colorectal cancer (CRC), highlighting the need for comprehensive knowledge of sulfur metabolism within the human gut. Microbial sulfidogenesis produces genotoxic hydrogen sulfide (H₂S) in the human colon using inorganic (sulfate) and organic (taurine/cysteine/methionine) substrates; however, the majority of studies have focused on sulfate reduction using dissimilatory sulfite reductases (Dsr).

RESULTS

Here, we show that genes for microbial sulfur metabolism are more abundant and diverse than previously observed and are statistically associated with CRC. Using ~ 17,000 bacterial genomes from publicly available stool metagenomes, we studied the diversity of sulfur metabolic genes in 667 participants across different health statuses: healthy, adenoma, and carcinoma. Sulfidogenic genes were harbored by 142 bacterial genera and both organic and inorganic sulfidogenic genes were associated with carcinoma. Significantly, the anaerobic sulfite reductase (asr) genes were twice as abundant as dsr, demonstrating that Asr is likely a more important contributor to sulfate reduction in the human gut than Dsr. We identified twelve potential pathways for reductive taurine metabolism and discovered novel genera harboring these pathways. Finally, the prevalence of metabolic genes for organic sulfur indicates that these understudied substrates may be the most abundant source of microbially derived H₂S.

CONCLUSIONS

Our findings significantly expand knowledge of microbial sulfur metabolism in the human gut. We show that genes for microbial sulfur metabolism in the human gut are more prevalent than previously known, irrespective of health status (i.e., in both healthy and diseased states). Our results significantly increase the diversity of pathways and bacteria that are associated with microbial sulfur metabolism in the human gut. Overall, our results have implications for understanding the role of the human gut microbiome and its potential contributions to the pathogenesis of CRC. Video abstract.

Impacts of MicroRNAs Induced by the Gut Microbiome on Regulating the Development of Colorectal Cancer

Although a dysfunctional gut microbiome is strongly linked to colorectal cancer (CRC), our knowledge of the mediators between CRC and the microbiome is limited. MicroRNAs (miRNAs) affect critical cellular processes, such as apoptosis, proliferation, and differentiation, and contribute to the regulation of CRC progression. Increasingly, studies found that miRNAs can significantly mediate bidirectional interactions between the host and the microbiome. Notably, miRNA expression is regulated by the gut microbiome, which subsequently affects the host transcriptome, thereby influencing the development of CRC. This study typically focuses on the specific functions of the microbiome in CRC and their effect on CRC-related miRNA production and reviews the role of several bacteria on miRNA, including Fusobacterium nucleatum, Escherichia coli, enterotoxigenic Bacteroides fragilis, and Faecalibacterium prausnitzii. Based on the important roles of miRNAs and the gut microbiome in CRC, strategies for modulating miRNA expression and regulating the gut microbiome composition need to be applied, such as bioactive dietary components and fecal microorganism transplantation.

Exome and Tissue-Associated Microbiota as Predictive Markers of Response to Neoadjuvant Treatment in Locally Advanced Rectal Cancer

The clinical and pathological responses to multimodal neoadjuvant therapy in locally advanced rectal cancers (LARCs) remain unpredictable, and robust biomarkers are still lacking. Recent studies have shown that tumors present somatic molecular alterations related to better treatment response, and it is also clear that tumor-associated bacteria are modulators of chemotherapy and immunotherapy efficacy, therefore having implications for long-term survivorship and a good potential as the biomarkers of outcome. Here, we performed whole exome sequencing and 16S ribosomal RNA (rRNA) amplicon sequencing from 44 pre-treatment LARC biopsies from Argentinian and Brazilian patients, treated with neoadjuvant chemoradiotherapy or total neoadjuvant treatment, searching for predictive biomarkers of response (responders, n = 17; non-responders, n = 27). In general, the somatic landscape of LARC was not capable to predict a response; however, a significant enrichment in mutational signature SBS5 was observed in non-responders (p = 0.0021), as well as the co-occurrence of APC and FAT4 mutations (p < 0.05). Microbiota studies revealed a similar alpha and beta diversity of bacteria between response groups. Yet, the linear discriminant analysis (LDA) of effect size indicated an enrichment of Hungatella, Flavonifractor, and Methanosphaera (LDA score ≥3) in the pre-treatment biopsies of responders, while non-responders had a higher abundance of Enhydrobacter, Paraprevotella (LDA score ≥3) and Finegoldia (LDA score ≥4). Altogether, the evaluation of these biomarkers in pre-treatment biopsies could eventually predict a neoadjuvant treatment response, while in post-treatment samples, it could help in guiding non-operative treatment strategies.

Does the Microbiota Composition Influence the Efficacy of Colorectal Cancer Immunotherapy?

Colorectal cancer (CRC) is the second most common malignancy globally, and many people with CRC suffer the fate of death. Due to the importance of CRC and its negative impact on communities, treatment strategies to control it or increase patient survival are being studied. Traditional therapies, including surgery and chemotherapy, have treated CRC patients. However, with the advancement of science, we are witnessing the emergence of novel therapeutic approaches such as immunotherapy for CRC treatment, which have had relatively satisfactory clinical outcomes. Evidence shows that gastrointestinal (GI) microbiota, including various bacterial species, viruses, and fungi, can affect various biological events, regulate the immune system, and even treat diseases like human malignancies. CRC has recently shown that the gut microorganism pattern can alter both antitumor and pro-tumor responses, as well as cancer immunotherapy. Of course, this is also true of traditional therapies because it has been revealed that gut microbiota can also reduce the side effects of chemotherapy. Therefore, this review summarized the effects of gut microbiota on CRC immunotherapy.

Bacteria-Mediated Oncogenesis and the Underlying Molecular Intricacies: What We Know So Far

Cancers are known to have multifactorial etiology. Certain bacteria and viruses are proven carcinogens. Lately, there has been in-depth research investigating carcinogenic capabilities of some bacteria. Reports indicate that chronic inflammation and harmful bacterial metabolites to be strong promoters of neoplasticity. Helicobacter pylori-induced gastric adenocarcinoma is the best illustration of the chronic inflammation paradigm of oncogenesis. Chronic inflammation, which produces excessive reactive oxygen species (ROS) is hypothesized to cause cancerous cell proliferation. Other possible bacteria-dependent mechanisms and virulence factors have also been suspected of playing a vital role in the bacteria-induced-cancer(s). Numerous attempts have been made to explore and establish the possible relationship between the two. With the growing concerns on anti-microbial resistance and over-dependence of mankind on antibiotics to treat bacterial infections, it must be deemed critical to understand and identify carcinogenic bacteria, to establish their role in causing cancer.

Utility of Continuous Disease Subtyping Systems for Improved Evaluation of Etiologic Heterogeneity

Molecular pathologic diagnosis is important in clinical (oncology) practice. Integration of molecular pathology into epidemiological methods (i.e., molecular pathological epidemiology) allows for investigating the distinct etiology of disease subtypes based on biomarker analyses, thereby contributing to precision medicine and prevention. However, existing approaches for investigating etiological heterogeneity deal with categorical subtypes. We aimed to fully leverage continuous measures available in most biomarker readouts (gene/protein expression levels, signaling pathway activation, immune cell counts, microbiome/microbial abundance in tumor microenvironment, etc.). We present a cause-specific Cox proportional hazards regression model for evaluating how the exposure-disease subtype association changes across continuous subtyping biomarker levels. Utilizing two longitudinal observational prospective cohort studies, we investigated how the association of alcohol intake (a risk factor) with colorectal cancer incidence differed across the continuous values of tumor epigenetic DNA methylation at long interspersed nucleotide element-1 (LINE-1). The heterogeneous alcohol effect was modeled using different functions of the LINE-1 marker to demonstrate the method's flexibility. This real-world proof-of-principle computational application demonstrates how the new method enables visualizing the trend of the exposure effect over continuous marker levels. The utilization of continuous biomarker data without categorization for investigating etiological heterogeneity can advance our understanding of biological and pathogenic mechanisms.

Prognostic Value of Fusobacterium nucleatum after Abdominoperineal Resection for Anal Squamous Cell Carcinoma

Main prognostic factors of anal squamous cell carcinoma (ASCC) are tumor size, differentiation, lymph node involvement, and male gender. However, they are insufficient to predict relapses after exclusive radiotherapy (RT) or chemoradiotherapy (CRT). Fusobacterium nucleatum has been associated with poor prognosis in several digestive cancers. In this study, we assessed the association between intratumoral F. nucleatum load and clinico-pathological features, relapse, and survival in patients with ASCC who underwent abdominoperineal resection (APR) after RT/CRT. We retrospectively analyzed surgical samples from a cohort of 166 patients with ASCC who underwent APR. F. nucleatum 16S rRNA gene sequences were quantified using real-time quantitative PCR. We associated F. nucleatum load with classical clinicopathological features, overall survival (OS), disease-free survival (DFS), and metastasis-free survival (MFS) using Cox regression univariate and multivariate analyses. Tumors harboring high loads of F. nucleatum (highest tercile) showed longer OS and DFS (median: not reached vs. 50.1 months, p = 0.01, and median: not reached vs. 18.3 months, p = 0.007, respectively). High F. nucleatum load was a predictor of longer OS (HR = 0.55, p = 0.04) and DFS (HR = 0.50, p = 0.02) in multivariate analysis. High F. nucleatum load is an independent favorable prognostic factor in patients with ASCC who underwent APR.

Fusobacterium nucleatum Affects Cell Apoptosis by Regulating Intestinal Flora and Metabolites to Promote the Development of Colorectal Cancer

BACKGROUND/AIMS

Intestinal flora, especially Fusobacterium nucleatum (Fn), can affect the development of colorectal cancer (CRC). In this study, we examined the composition of intestinal flora and their metabolites in the tissues, serum and feces of CRC patients.

MATERIALS AND METHODS

CRC tissues, adjacent normal colonic tissues, fecal and serum samples were collected from CRC patients who received surgical treatment between January 2018 and January 2020. Fecal and serum samples were collected from healthy individuals for comparison. In addition, fecal samples were collected from BALB/c female mice. SW480, a human CRC cell line, was utilized for in vitro studies. The experiments involved 1H-NMR-based metabolomics analysis, targeted and untargeted mass spectrometry analysis, and intestinal flora 16S rDNA V4 region sequencing.

RESULTS

The abundance of Bacteroides and propionic acid concentration were decreased and that of Lactobacillus and lactic acid concentration were increased in CRC tissues. In addition, the abundances of Ruminococcus, Prevotella, and Sutterell were decreased in CRC patients. The levels of leucine and isoleucine were decreased in the serum and tumor tissues of CRC patients. Aspartate, glutamate and glutathione levels were elevated in the tissues of CRC patients only. The serum glutamine, tyrosine, valine, alanine, and histidine levels were decreased significantly. Lactic acid inhibited and propionic acid promoted apoptosis among SW480 CRC cells.

CONCLUSION

Fn affected the apoptosis of CRC cells and promoted the progression of CRC by affecting the distribution of intestinal flora, which altered the concentrations of metabolites such as lactic acid, propionic acid. Intestinal flora could regulate amino acid metabolism.

Subgingival Periopathogens Assessment and Clinical Periodontal Evaluation of Gastric Cancer Patients-A Cross Sectional Pilot Study

Oral microbiota have shown a higher bacterial diversity in patients with cancers of the digestive tract, with higher levels of periopathogens. Recent studies have shown that Fusobacterium links to gastro-intestinal neoplastic tissue and accelerates its progression, as well as worsening patient outcome. The present pilot study was carried out between February and December 2020 to evaluate the possible association between the abundance of some periopathogens (Fusobacterium nucleatum, Porphyromonas gingivalis, Aggregatibacter actinomycetemcomitans, Treponema denticola and Tannerella forsythia) in subgingival plaque and periodontal status with characteristics of gastric cancer. The study was performed on a sample of 24 patients with gastric cancer from the 1st Department of Surgery and Department of Gastroenterology within the Clinical County Hospital of Emergency of Craiova, Romania. The patients' oral cavity was examined, gingival crevicular samples were collected, and signs of periodontal disease were recorded. On the histopathological exam, the differentiation grade and size of the tumour were registered. Our results showed that, from the periopathogens studied, the most abundant bacteria were F. nucleatum followed by T. forsythia in all groups. In our present study, the strong correlation between tumour dimension and all periodontal parameters but also between tumour dimension and F. nucleatum could suggest a positive association between periodontal disease, tumoral growth and periopathogens implication in this process.

Bugs as Drugs: Understanding the Linkage between Gut Microbiota and Cancer Treatment Microbiome in Cancer Therapy

BACKGROUND

The commensal microbiota is known to regulate host physiology. Dysbiosis or compromised Resilience in the microbial ecology is related to the impending risk of cancer. A potential link between cancer and microbiota is indicated by a lot of evidence.

OBJECTIVE

The current review explores in detail the various links leading to and /or facilitating oncogenesis, providing sound reasoning or a basis for its utilization as potential therapeutic targets. The present review emphasizes the existing knowledge of the microbiome in cancer and further elaborates on the factors like genetic modifications, effects of dietary components, and environmental agents that are considered to assess the direct and indirect effect of microbes in the process of oncogenesis and on the host's health. Strategies modulating the microbiome and novel biotherapeutics are also discussed. Pharmacomicrobiomics is one such niche accounting for the interplay between the microbiome, xenobiotic, and host responses is also looked upon.

METHODS

The literature search strategy for this review was conducted by following the methodology of the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). The method includes the collection of data from different search engines like PubMed, ScienceDirect, SciFinder etc. to get coverage of relevant literature for accumulating appropriate information regarding microbiome, cancer, and their linkages.

RESULTS

These considerations are made to expand the existing literature on the role of gut microbiota on the host's health, the interaction between host and microbiota, and the reciprocal relationship between the microbiome and modified neoplastic cells.

CONCLUSION

Potential therapeutic implications of cancer microbiomes that are yet unexplored and have rich therapeutic dividends improving human health are discussed in detail in this review.

The Microbiome: the Link to Colorectal Cancer and Research Opportunities

OPINION STATEMENT

In recent years, we have seen an increase in the study and interest of the role of the microbiome in the development of malignancies, their progression, and evasion of therapies. This has been particularly fruitful in the case of colorectal cancer; multiple investigators have described correlative observations as well as hypotheses strengthened in preclinical studies that have begun to elucidate the critical role the gut and tumoral microbiome plays in carcinogenesis. Furthermore, these landmark studies lay the groundwork in describing the microbiome's role in carcinogenesis and provide a rich field of future study. Here, we review contemporary understandings of these observations and proposed mechanisms behind them.

Fusobacterium nucleatum and cancer

Accumulating evidence demonstrates that the oral pathobiont Fusobacterium nucleatum is involved in the progression of an increasing number of tumors types. Thus far, the mechanisms underlying tumor exacerbation by F. nucleatum include the enhancement of proliferation, establishment of a tumor‐promoting immune environment, induction of chemoresistance, and the activation of immune checkpoints. This review focuses on the mechanisms that mediate tumor‐specific colonization by fusobacteria. Elucidating the mechanisms mediating fusobacterial tumor tropism and promotion might provide new insights for the development of novel approaches for tumor detection and treatment.

Vanillin Derivatives Reverse Fusobacterium nucleatum-Induced Proliferation and Migration of Colorectal Cancer Through E-Cadherin/β-Catenin Pathway

Colorectal cancer (CRC) is a common clinical malignant tumor and closely related to intestinal microbiome disorders. Especially, Fusobacterium nucleatum (F. nucleatum) is one of the most prevalent pathogens in CRC. However, its change in CRC patients of Northwest China, an area with a high incidence of gastrointestinal tumors, is unclear, and therapeutic strategies targeting F. nucleatum remain unresolved. Here, fecal samples of healthy people and CRC patients were studied using 16S rRNA sequencing to explore microbial community alterations. Additionally, vanillin derivate (IPM711 and IPM712) intervention by coculture with CRC cells and potential mechanism were investigated. Results showed that intestinal microbial homeostasis was gradually dysregulated, and the abundance of Fusobacterium was higher in CRC patients. Moreover, IPM711 and IPM712 showed better anti-F. nucleatum activity than vanillin by increasing cell membrane permeability and destroying bacterial integrity. In addition, IPM711 and IPM712 could downregulate the expression of E-cadherin and β-catenin, thus, suppressing the migration of HCT116. Collectively, IPM711 and IPM712 have both anticolorectal cancer and anti-F. nucleatum activities, providing potential natural product drug candidates for microbe-targeted strategies for the treatment of CRC.

The Regional Specificity of Mucosa-Associated Microbiota in Patients with Distal Colorectal Cancer

BACKGROUND/AIMS

Recent studies have demonstrated that the populations of several microbes are significantly increased in fecal samples from patients with colorectal cancer (CRC), suggesting their involvement in the development of CRC. The aim of this study was to identify microbes which are increased in distal CRCs and to identify the specific location of microbes increased in mucosal tissue around the tumor.

METHODS

Tissue specimens were collected from surgical resections of 28 distal CRCs. Five samples were collected from each specimen (location A: tumor, B: adjacent normal mucosa, C: normal mucosa 1 cm proximal to the tumor, D: normal mucosa 3 cm proximally, and E: normal mucosa 6 cm proximally). The microbiota in the sample were analyzed using 16S rRNA gene amplicon sequencing and the relative abundance (RA) of microbiota compared among the 5 locations.

RESULTS

At the genus level, the RA of Fusobacterium and Streptococcus at location A was the highest among the 5 locations, significantly different from that in location E. The dominant species of each genus was Fusobacterium nucleatum and Streptococcus anginosus. The RAs of these species gradually decreased from locations B to E with a statistically significant difference in F. nucleatum. The genus Peptostreptococcus also showed a similar trend, and the RA of Peptostreptococcus stomatis in location A was significantly associated with depth of tumor invasion and tumor size.

CONCLUSION

Although the clinical relevance is not clear yet, these results suggest that F. nucleatum, S. anginosus, and P. stomatis can spread to the adjacent normal tissues and may change the surrounding microenvironment to support the progression of CRC.

Airway Fusobacterium is Associated with Poor Response to Immunotherapy in Lung Cancer

PURPOSE

There is a major limitation in the immunotherapy for solid cancer is that it only benefited a minority of cancer patients. This study aims to investigate whether the differential composition of the lung microbiome could affect the sustained clinical responses in lung cancers treated with immunotherapy.

METHODS

Twenty-seven non-responders and 19 responders treated with anti-PD-1 therapy were included in the discovery set. Bacterial load in bronchoalveolar lavage from lung cancer patients was examined by quantitative PCR of 16S rRNA copies. Bacterial 16S rDNA was sequenced using the Illumina HiSeq on the 16S rDNA V3-V4 variable region. Operational taxonomic unit (OTU) analysis was performed using VSEARCH v2. The α-diversity and β-diversity were calculated using QIIME software.

RESULTS

The mean copy number of bacterial 16S DNA levels significantly decreased after anti-PD-1 treatment (after: 1.8 ± 0.6×104 copies per milliliter vs prior to treatment: 3.3 ± 1.1x104, p = 0.0036). In addition, longitudinal analysis revealed that microbial diversity was reduced taxonomically after treatment compared to those prior to the treatment (Shannon values: before: 3.291 ± 0.067 vs after: 2.668 ± 0.168, p < 0.01). Further, we observed a reduction of Fusobacterium nucleatum, including phylum Fusobacteria (p < 0.01), class Fusobacteria (p < 0.01), order Fusobacteria (p < 0.01), family Fusobacteria (p < 0.01), genus Fusobacteria (p = 0.025) in the responders post anti-PD-1 treatment. However, there was no significant difference of Fusobacterium in non-responders. An independent cohort was used to validate the levels of Fusobacterium, demonstrating that patients with higher abundance of Fusobacterium prior to treatment were significantly more likely to have poor response to anti-PD-1 therapy (p < 0.001).

CONCLUSION

Airway enriched Fusobacterium prior to anti-PD-1 therapy is associated with poor response in lung cancer, which indicated that potential resistance to immunotherapy can be attributed to lung microbiome.

Identification of the Crucial Role of CCL22 in F. nucleatum-Related Colorectal Tumorigenesis that Correlates With Tumor Microenvironment and Immune Checkpoint Therapy

Colorectal cancer (CRC) is the third most common malignant cancer worldwide with the second highest mortality. Gut microbiota can educate the tumor microenvironment (TME), consequently influencing the efficacy of immune checkpoint inhibitors (ICIs). Fusobacterium nucleatum is one of the most crucial bacteria contributing to colorectal tumorigenesis, but the molecular mechanisms between F. nucleatum and TME or ICIs are poorly investigated. In the present study, we firstly analyzed differentially expressed genes and the biological functions between F. nucleatum-infected and uninfected CRC cell lines, with the findings that CCL22 mRNA expression was markedly upregulated after F. nucleatum infection. Moreover, the survival analysis showed that CCL22 was significantly associated with the overall survival of CRC patients. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analysis suggested that CCL22 was related to immune-related terms. Furthermore, the ESTIMATE analysis indicated that the high-CCL22-expression subgroup had a higher immune/stromal/estimate score and lower tumor purity. The CIBERSORT analysis indicated that the high-CCL22-expression group had more immune-suppressive cells and less antitumor immune cells. In addition, immune checkpoint genes and cytotoxic genes were positively correlated with CCL22 expression. The immunophenoscore analysis suggested that CCL22 was associated with the IPS-CTLA4 and PD1/PD-L1/PD-L2 score. Interestingly, CCL22 expression in the KRAS and APC mutation groups was markedly reduced compared to that of the wild groups. In summary, our study provided evidence that CCL22 might play a crucial role in F. nucleatum-related colorectal tumorigenesis and correlate with TME and ICIs, which deserves further study.

Dysbiosis of skin microbiome and gut microbiome in melanoma progression

Background

The microbiome alterations are associated with cancer growth and may influence the immune system and response to therapy. Particularly, the gut microbiome has been recently shown to modulate response to melanoma immunotherapy. However, the role of the skin microbiome has not been well explored in the skin tumour microenvironment and the link between the gut microbiome and skin microbiome has not been investigated in melanoma progression. Therefore, the aim of the present study was to examine associations between dysbiosis in the skin and gut microbiome and the melanoma growth using MeLiM porcine model of melanoma progression and spontaneous regression.

Results

Parallel analysis of cutaneous microbiota and faecal microbiota of the same individuals was performed in 8 to 12 weeks old MeLiM piglets. The bacterial composition of samples was analysed by high throughput sequencing of the V4-V5 region of the 16S rRNA gene. A significant difference in microbiome diversity and richness between melanoma tissue and healthy skin and between the faecal microbiome of MeLiM piglets and control piglets were observed. Both Principal Coordinate Analysis and Non-metric multidimensional scaling revealed dissimilarities between different bacterial communities. Linear discriminant analysis effect size at the genus level determined different potential biomarkers in multiple bacterial communities. Lactobacillus, Clostridium sensu stricto 1 and Corynebacterium 1 were the most discriminately higher genera in the healthy skin microbiome, while Fusobacterium, Trueperella, Staphylococcus, Streptococcus and Bacteroides were discriminately abundant in melanoma tissue microbiome. Bacteroides, Fusobacterium and Escherichia-Shigella were associated with the faecal microbiota of MeLiM piglets. Potential functional pathways analysis based on the KEGG database indicated significant differences in the predicted profile metabolisms between the healthy skin microbiome and melanoma tissue microbiome. The faecal microbiome of MeLiM piglets was enriched by genes related to membrane transports pathways allowing for the increase of intestinal permeability and alteration of the intestinal mucosal barrier.

Conclusion

The associations between melanoma progression and dysbiosis in the skin microbiome as well as dysbiosis in the gut microbiome were identified. Results provide promising information for further studies on the local skin and gut microbiome involvement in melanoma progression and may support the development of new therapeutic approaches.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-022-02458-5.

Altered gut metabolites and microbiota interactions are implicated in colorectal carcinogenesis and can be non-invasive diagnostic biomarkers

BACKGROUND

Gut microbiota contributes to colorectal cancer (CRC) pathogenesis through microbes and their metabolites. The importance of microbiota-associated metabolites in colorectal carcinogenesis highlights the need to investigate the gut metabolome along the adenoma-carcinoma sequence to determine their mechanistic implications in the pathogenesis of CRC. To date, how and which microbes and metabolites interactively promote early events of CRC development are still largely unclear. We aim to determine gut microbiota-associated metabolites and their linkage to colorectal carcinogenesis.

RESULTS

We performed metabolomics and metagenomics profiling on fecal samples from 386 subjects including 118 CRC patients, 140 colorectal adenomas (CRA) patients and 128 healthy subjects as normal controls (NC). We identified differences in the gut metabolite profiles among NC, CRA and CRC groups by partial least squares-discriminant and principal component analyses. Among the altered metabolites, norvaline and myristic acid showed increasing trends from NC, through CRA, to CRC. CRC-associated metabolites were enriched in branched-chain amino acids, aromatic amino acids and aminoacyl-tRNA biosynthesis pathways. Moreover, metabolites marker signature (twenty metabolites) classified CRC from NC subjects with an area under the curve (AUC) of 0.80, and CRC from CRA with an AUC of 0.79. Integrative analyses of metabolomics and metagenomics profiles demonstrated that the relationships among CRC-associated metabolites and bacteria were altered across CRC stages; certain associations exhibited increasing or decreasing strengths while some were reversed from negative to positive or vice versa. Combinations of gut bacteria with the metabolite markers improved their diagnostic performances; CRC vs NC, AUC: 0.94; CRC vs CRA, AUC 0.92; and CRA vs NC, AUC: 0.86, indicating a potential for early diagnosis of colorectal neoplasia.

CONCLUSIONS

This study underscores potential early-driver metabolites in stages of colorectal tumorigenesis. The Integrated metabolite and microbiome analysis demonstrates that gut metabolites and their association with gut microbiota are perturbed along colorectal carcinogenesis. Fecal metabolites can be utilized, in addition to bacteria, for non-invasive diagnosis of colorectal neoplasia. Video Abstract.

Bacterial Translocation in Gastrointestinal Cancers and Cancer Treatment

In recent years, there has been increasing evidence that gut microbiota is associated with the onset and exacerbation of various diseases, such as gastrointestinal cancer. For instance, it is well known that local inflammation of the intestinal tract in colorectal cancer that is caused by the increased number of Fusobacterium, due to changes in the intestinal bacterial flora, is involved in carcinogenesis. In contrast, gut bacteria or their products, pathogen-associated molecular patterns, not only cause intestinal inflammation but also invade the bloodstream through dysbiosis and gut barrier dysfunction, thereby leading to systemic inflammation, namely bacterial translocation. The involvement of bacterial translocation in the carcinogenesis of gastrointestinal cancers and their prognosis is increasingly being recognized. The Toll-like receptor signaling pathways plays an important role in the carcinogenesis of such cancers. In addition, bacterial translocation influences the treatment of cancers such as surgery and chemotherapy. In this review, we outline the concept of bacterial translocation, summarize the current knowledge on the relationship between gut bacteria and gastrointestinal cancer, and provide future perspectives of this field.

A structurally unique Fusobacterium nucleatum tannase provides detoxicant activity against gallotannins and pathogen resistance

Colorectal cancer pathogenesis and progression is associated with the presence of Fusobacterium nucleatum and the reduction of acetylated derivatives of spermidine, as well as dietary components such as tannin-rich foods. We show that a new tannase orthologue of F. nucleatum (TanBFnn ) has significant structural differences with its Lactobacillus plantarum counterpart affecting the flap covering the active site and the accessibility of substrates. Crystallographic and molecular dynamics analysis revealed binding of polyamines to a small cavity that connects the active site with the bulk solvent which interact with catalytically indispensable residues. As a result, spermidine and its derivatives, particularly N8 -acetylated spermidine, inhibit the hydrolytic activity of TanBFnn and increase the toxicity of gallotannins to F. nucleatum. Our results support a model in which the balance between the detoxicant activity of TanBFnn and the presence of metabolic inhibitors can dictate either conducive or unfavourable conditions for the survival of F. nucleatum.

Oral pathogen in the pathogenesis of colorectal cancer

The human body contains more than 100 trillion microorganisms, including the oral cavity, the skin, and the gastrointestinal tract. After the gastrointestinal tract, the oral cavity harbors one of the most diverse microbial communities within the human body and harbors more than 770 species of bacteria. The composition of the oral and gut microbiomes is quite different, but there may be a microbiological link between the two mucosal sites during the course of disease. More studies indicate that oral bacteria can disseminate to the distal gut via enteral or hematogenous routes. This is mostly obvious in periodontitis, where specific bacteria, such as Fusobacterium nucleatum and Porphyromonas gingivalis, show this pathogenic feature. The translocation of oral microbes to the gut may give rise to a variety of gastrointestinal diseases, including colorectal cancer. However, the precise role that oral microbe play in colorectal cancer has not been fully illustrated. Here, we summarize the current researches on possible pathways of ectopic gut colonization by oral bacteria and their possible contribution to the pathogenesis of colorectal cancer. Understanding the correlation of the oral-to-gut microbial axis in the pathogenesis of colorectal cancer will contribute to precise diagnosis and effective treatment.

Moxibustion may delay the aging process of Wistar rats by regulating intestinal microbiota

As one of the important treatments of health care and anti-aging in traditional Chinese medicine (TCM), moxibustion has been proved to have the effects of scavenging free radicals, anti-oxidation, reducing inflammatory reaction, regulating immunity and so on. Recent studies have shown that intestinal microbiota affect the process of aging. The relationship between aging, moxibustion and intestinal microbiota is still unclear. In this study, we explored the effects of moxibustion at Guanyuan (RN4) acupoint on intestinal microbiota, short-chain fatty acids and immunological characteristics of young and elder female Wistar rats to explore the relationship between aging, moxibustion and intestinal microbiota. Six 12-week-old female Wistar rats were young group (Y), and twelve 36-week-old female Wistar rats were randomly divided into elder group (C) and moxibustion group (M). The rats in M group were received mild moxibustion at Guanyuan (RN4) acupoint, 20 min/d for 40 days. The rats in Y group and C group were not given any therapeutic intervention. The results showed that moxibustion increased the abundance of intestinal probiotics (mainly Lactobacillus) and the level of short chain fatty acids, the microcirculation blood flow around Guanyuan (RN4) acupoint was also significantly improved in elder rats. In addition, the expression of MyD88, MAPK, TRAF6, NF-κB in intestinal tissue was down-regulated, and the levels of inflammatory cytokines in intestinal were decreased.

Fusobacterium nucleatum promotes colorectal cancer metastasis through miR-1322/CCL20 axis and M2 polarization

Colorectal cancer (CRC) is one of the most common malignant tumors and is associated with Fusobacterium nucleatum (F. nucleatum, Fn) infection. In this study, we explored the role of F. nucleatum in the CRC metastasis. Our results showed that the abundance of F. nucleatum was enriched in the feces and tumors of patients with CRC and tended to increase in stage IV compared to stage I in patients with metastatic CRC. Tumor-derived CCL20 activated by F. nucleatum not only increases CRC metastasis, but also participates in the reprograming of the tumor microenvironment. F. nucleatum promoted macrophage infiltration through CCL20 activation and simultaneously induced M2 macrophage polarization, enhancing the metastasis of CRC. In addition, we identified using database prediction and luciferase activity hat miR-1322, a candidate regulatory micro-RNA, could bind to CCL20 directly. F. nucleatum infection decreased the expression of miR-1322 by activating the NF-κB signaling pathway in CRC cells. In conclusion, F. nucleatum promotes CRC metastasis through the miR-1322/CCL20 axis and M2 polarization.

Potential Role of the Gut Microbiome In Colorectal Cancer Progression

An increasing number of studies have revealed that the progression of colorectal cancer (CRC) is related to gut microbiome composition. Under normal conditions, the gut microbiome acts as a barrier to other pathogens or infections in the intestine and modulates inflammation by affecting the host immune system. These gut microbiota are not only related to the intestinal inflammation associated with tumorigenesis but also modulation of the anti-cancer immune response. Thus, they are associated with tumor progression and anti-cancer treatment efficacy. Studies have shown that the gut microbiota can be used as biomarkers to predict the effect of immunotherapy and improve the efficacy of immunotherapy in treating CRC through modulation. In this review, we discuss the role of the gut microbiome as revealed by recent studies of the growth and progression of CRC along with its synergistic effect with anti-cancer treatment modalities.

Fusobacterium nucleatum promotes esophageal squamous cell carcinoma progression via the NOD1/RIPK2/NF-κB pathway

Fusobacterium nucleatum, found in the oral cavity, influences the progression of gastrointestinal cancers. Additionally, our previous results suggested that F. nucleatum is associated with poor patient prognosis in esophageal squamous cell carcinoma (ESCC). However, the mechanism by which F. nucleatum affects aggressive tumor behavior has yet to be elucidated. We have conducted this clinical, in vitro, and in vivo study to clarify the mechanism of ESCC progression induced by F. nucleatum. Transmission electron microscopy revealed that F. nucleatum invaded and occupied ESCC cells and impacted gene and protein expression. Comprehensive mRNA expression and pathway enrichment analyses of F. nucleatum-treated ESCC cells identified the "NF-κB" and "NOD-like receptor" signaling pathways as enriched. We confirmed the relationship between the presence of F. nucleatum and NF-κB activation in resected ESCC tissues. Furthermore, F. nucleatum-treated ESCC cells demonstrated enhanced growth ability, and NF-κB activation, as well as overexpression of NOD1 and phosphorylated RIPK2. Furthermore, treated cells showed accelerated tumor growth, with NF-κB activation in xenograft models. F. nucleatum invaded ESCC cells and induced the NF-κB pathway through the NOD1/RIPK2 pathway, leading to tumor progression.

Fusobacterium nucleatum and Bacteroides fragilis detection in colorectal tumours: Optimal target site and correlation with total bacterial load

Background

Mucosal infiltration by certain bacterial species may contribute to the development and progression of colorectal cancer (CRC). There is considerable variation in reported detection rates in human CRC samples and the extent to which bacterial infiltration varies across regions of the primary tumour is unknown. This study aimed to determine if there is an optimal site for bacterial detection within CRC tumours.

Methods

Presence of target bacterial species was assessed by quantitative real-time PCR (qPCR) in 42 human CRC tumours. Abundance in primary tumour regions, normal epithelium and at metastatic sites was investigated in an expanded cohort of 51 patients. Species presence/absence was confirmed by diversity profiling in five patients. Correlation with total bacterial load and clinicopathological features was assessed.

Results

Fusobacterium nucleatum and Bacteroides fragilis were detected in tumours from 43% and 24% of patients, respectively (17% positive for both species). The optimal detection site was the tumour luminal surface (TLS). Patients testing positive at the TLS frequently tested negative at other sites, including central tumour and invasive margin. F. nucleatum was detected at a higher frequency in tumour versus normal epithelium (p < 0.01) and was associated with more advanced disease (p = 0.01). Detection of both species correlated with total bacterial load. However, corroboration of qPCR results via diversity profiling suggests detection of these species may indicate a specific microbial signature.

Conclusions

This study supports a role for F. nucleatum in CRC development. Presence of F. nucleatum and B. fragilis varies across primary tumour regions, with the TLS representing the optimal site for bacterial detection.

Accuracy and Clinical Relevance of Intra-Tumoral Fusobacterium nucleatum Detection in Formalin-Fixed Paraffin-Embedded (FFPE) Tissue by Droplet Digital PCR (ddPCR) in Colorectal Cancer

The use of droplet digital PCR (ddPCR) to identify and quantify low-abundance targets is a significant advantage for accurately detecting potentially oncogenic bacteria. Fusobacterium nucleatum (Fn) is implicated in colorectal cancer (CRC) tumorigenesis and is becoming an important prognostic biomarker. We evaluated the detection accuracy and clinical relevance of Fn DNA by ddPCR in a molecularly characterized, formalin-fixed, paraffin-embedded (FFPE) CRC cohort previously analyzed by qPCR for Fn levels. Following a ddPCR assay optimization and an analytical evaluation, Fn DNA were measured in 139 CRC FFPE cases. The measures of accuracy for Fn status compared to the prior results generated by qPCR and the association with clinicopathological and molecular patients' features were also evaluated. The ddPCR-based Fn assay was sensitive and specific to positive controls. Fn DNA were detected in 20.1% of cases and further classified as Fn-high and Fn-low/negative, according to the median amount of Fn DNA that were detected in all cases and associated with the patient's worst prognosis. There was a low agreement between the Fn status determined by ddPCR and qPCR (Cohen's Kappa = 0.210). Our findings show that ddPCR can detect and quantify Fn in FFPE tumor tissues and highlights its clinical relevance in Fn detection in a routine CRC setting.

The Impact of the Microbiome on Resistance to Cancer Treatment with Chemotherapeutic Agents and Immunotherapy

Understanding the mechanisms of resistance to therapy in human cancer cells has become a multifaceted limiting factor to achieving optimal cures in cancer patients. Besides genetic and epigenetic alterations, enhanced DNA damage repair activity, deregulation of cell death, overexpression of transmembrane transporters, and complex interactions within the tumor microenvironment, other mechanisms of cancer treatment resistance have been recently proposed. In this review, we will summarize the preclinical and clinical studies highlighting the critical role of the microbiome in the efficacy of cancer treatment, concerning mainly chemotherapy and immunotherapy with immune checkpoint inhibitors. In addition to involvement in drug metabolism and immune surveillance, the production of microbiota-derived metabolites might represent the link between gut/intratumoral bacteria and response to anticancer therapies. Importantly, an emerging trend of using microbiota modulation by probiotics and fecal microbiota transplantation (FMT) to overcome cancer treatment resistance will be also discussed.

Molecular and Pathology Features of Colorectal Tumors and Patient Outcomes Are Associated with Fusobacterium nucleatum and Its Subspecies animalis

BACKGROUND

Fusobacterium nucleatum (F. nucleatum) activates oncogenic signaling pathways and induces inflammation to promote colorectal carcinogenesis.

METHODS

We characterized F. nucleatum and its subspecies in colorectal tumors and examined associations with tumor characteristics and colorectal cancer-specific survival. We conducted deep sequencing of nusA, nusG, and bacterial 16s rRNA genes in tumors from 1,994 patients with colorectal cancer and assessed associations between F. nucleatum presence and clinical characteristics, colorectal cancer-specific mortality, and somatic mutations.

RESULTS

F. nucleatum, which was present in 10.3% of tumors, was detected in a higher proportion of right-sided and advanced-stage tumors, particularly subspecies animalis. Presence of F. nucleatum was associated with higher colorectal cancer-specific mortality (HR, 1.97; P = 0.0004). This association was restricted to nonhypermutated, microsatellite-stable tumors (HR, 2.13; P = 0.0002) and those who received chemotherapy [HR, 1.92; confidence interval (CI), 1.07-3.45; P = 0.029). Only F. nucleatum subspecies animalis, the main subspecies detected (65.8%), was associated with colorectal cancer-specific mortality (HR, 2.16; P = 0.0016), subspecies vincentii and nucleatum were not (HR, 1.07; P = 0.86). Additional adjustment for tumor stage suggests that the effect of F. nucleatum on mortality is partly driven by a stage shift. Presence of F. nucleatum was associated with microsatellite instable tumors, tumors with POLE exonuclease domain mutations, and ERBB3 mutations, and suggestively associated with TP53 mutations.

CONCLUSIONS

F. nucleatum, and particularly subspecies animalis, was associated with a higher colorectal cancer-specific mortality and specific somatic mutated genes.

IMPACT

Our findings identify the F. nucleatum subspecies animalis as negatively impacting colorectal cancer mortality, which may occur through a stage shift and its effect on chemoresistance.