Association Between Fusobacterium nucleatum, Pathway Mutation, and Patient Prognosis in Colorectal Cancer

Presence of Fusobacterium nucleatum in relation to patient survival and an acidic environment in oesophagogastric junction and gastric cancers

BACKGROUND

Fusobacterium nucleatum inhabits the oral cavity and affects the progression of gastrointestinal cancer. Our prior findings link F. nucleatum to poor prognosis in oesophageal squamous cell carcinoma via NF-κB pathway. However, its role in oesophagogastric junction and gastric adenocarcinoma remains unexplored. We investigated whether F. nucleatum influences these cancers, highlighting its potential impact.

METHODS

Two cohorts of EGJ and gastric adenocarcinoma patients (438 from Japan, 380 from the USA) were studied. F. nucleatum presence was confirmed by qPCR, FISH, and staining. Patient overall survival (OS) was assessed based on F. nucleatum positivity. EGJ and gastric adenocarcinoma cell lines were exposed to F. nucleatum to study molecular and phenotypic effects, validated in xenograft mouse model.

RESULTS

In both cohorts, F. nucleatum-positive EGJ or gastric adenocarcinoma patients had notably shorter OS. F. nucleatum positivity decreased in more acidic tumour environments. Cancer cell lines with F. nucleatum showed enhanced proliferation and NF-κB activation. The xenograft model indicated increased tumour growth and NF-κB activation in F. nucleatum-treated cells. Interestingly, co-occurrence of F. nucleatum and Helicobacter pylori, a known risk factor, was rare.

CONCLUSIONS

F. nucleatum can induce the NF-κB pathway in EGJ and gastric adenocarcinomas, leading to tumour progression and poor prognosis.

Gut Microbiome and colorectal cancer: discovery of bacterial changes with metagenomics application in Turkısh population

BACKGROUND

Colorectal cancer (CRC) is the 3rd most common cancer in the world and colonic carcinogenesis is a multifactorial disease that involves environmental and genetic factors. Gut microbiota plays a critical role in the regulation of intestinal homeostasis. Increasing evidence shows that the gut microbiome plays a role in CRC development and may be a biomarker for early diagnosis.

OBJECTIVE

This study aimed to determine the clinical prognostic significance of gut microbiota in CRC patients in the Turkish population by metagenomic analysis and to determine the microbial composition in tumor tissue biopsy samples.

METHODS

Tissue biopsies were taken from the participants with sterile forceps during colonoscopy and stored at -80 °C. Then, DNA isolation was performed from the tissue samples and the V3-V4 region of the 16 S rRNA gene was sequenced on the Illumina MiSeq platform. Quality control of the obtained sequence data was performed. Operational taxonomic units (OTUs) were classified according to the Greengenes database. Alpha diversity (Shannon index) and beta diversity (Bray-Curtis distance) analyses were performed. The most common bacterial species in CRC patients and healthy controls were determined and whether there were statistically significant differences between the groups was tested.

RESULTS

A total of 40 individuals, 13 CRC patients and 20 healthy control individuals were included in our metagenomic study. The mean age of the patients was 64.83 and BMI was 25.85. In CRC patients, the level of Bacteroidetes at the phylum taxonomy was significantly increased (p = 0.04), the level of Clostridia at the class taxonomy was increased (p = 0.23), and the level of Enterococcus at the genus taxonomy was significantly increased (p = 0.01). When CRC patients were compared with the control group, significant increases were detected in the species of Gemmiger formicilis (p = 0.15), Prevotella copri (p = 0.02) and Ruminococcus bromii (p = 0.001) at the species taxonomy.

CONCLUSIONS

Metagenomic analysis of intestinal microbiota composition in CRC patients provides important data for determining the treatment options for these patients. The results of this study suggest that it may be beneficial in terms of early diagnosis, poor prognosis and survival rates in CRC patients. In addition, this metagenomic study is the first study on the colon microbiome associated with CRC mucosa in the Turkish population.

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

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

Immunomodulation aspects of gut microbiome-related interventional strategies in colorectal cancer

Colorectal cancer (CRC), the third most common cancer worldwide, develops mainly due to the accumulation of genetic and epigenetic changes over many years. Substantial evidence suggests that gut microbiota plays a significant role in the initiation, progression, and control of CRC, depending on the balance between beneficial and pathogenic microorganisms. Nonetheless, gut microbiota composition by regulating the host immune response may either promote or inhibit CRC. Thus, modification of gut microbiota potentially impacts clinical outcomes of immunotherapy. Previous studies have indicated that therapeutic strategies such as probiotics, prebiotics, and postbiotics enhance the intestinal immune system and improve the efficacy of immunotherapeutic agents, potentially serving as a complementary strategy in cancer immunotherapy. This review discusses the role of the gut microbiota in the onset and development of CRC in relation to the immune response. Additionally, we focus on the effect of strategies manipulating gut microbiome on the immune response and efficacy of immunotherapy against CRC. We demonstrate that manipulation of gut microbiome can enhance immune response and outcomes of immunotherapy through downregulating Treg cells and other immunosuppressive cells while improving the function of T cells within the tumor; however, further research, especially clinical trials, are needed to evaluate its efficacy in cancer treatment.

Unveiling the Hidden Links: Periodontal Disease, Fusobacterium Nucleatum, and Cancers

PURPOSE OF REVIEW

Fusobacterium nucleatum (F. nucleatum), an anaerobic, gram-negative microbe, commonly found in human dental biofilm and the gut flora. It has long been known to have a higher concentration in periodontal disease and has recently been implicated in both oral and distant cancers such as colorectal, gastrointestinal, esophageal, breast, pancreatic hepatocellular, and genitourinary cancers. However, the mechanism of its involvement in the development of cancer has not been fully discussed. This review aims to cover biological molecular and clinical aspects of F. nucleatum and cancers.

RECENT FINDINGS

Studies indicate F. nucleatum promotes tumor development through chronic inflammation, immune evasion, cell proliferation activation, and direct cell interactions, as in oral squamous cell carcinoma (OSCC). In colorectal cancer (CRC), F. nucleatum contributes to tumorigenesis through β-catenin signaling and NF-κB activation. It also induces autophagy, leading to chemoresistance in CRC and esophageal cancers, and enhances tumor growth and metastasis in breast cancer by reducing T-cell infiltration. F. nucleatum is linked to carcinogenesis and increased bacterial diversity in OSCC, with improved oral hygiene potentially preventing OSCC. F. nucleatum triggers cancer by causing mutations and epigenetic changes through cytokines and reactive oxygen species. It also promotes chemoresistance in CRC. F. nucleatum may potentially serve as a diagnostic tool in various cancers, with non-invasive detection methods available. Further investigation is needed to discover its potential in the diagnosis and treatment of OSCC and other cancers.

Application of Fusobacterium nucleatum as a biomarker in gastrointestinal malignancies

The morbidity and mortality of gastrointestinal (GI) malignancies are among the highest in the world, posing a serious threat to human health. Because of the insidious onset of the cancer, it is difficult for patients to be diagnosed at an early stage, and it rapidly progresses to an advanced stage, resulting in poor treatment and prognosis. Fusobacterium nucleatum (F. nucleatum) is a gram-negative, spore-free anaerobic bacterium that primarily colonizes the oral cavity and is implicated in the development of colorectal, esophageal, gastric, and pancreatic cancers via various intricate mechanisms. Recent development in novel research suggests that F. nucleatum may function as a biomarker in GI malignancies. Detecting the abundance of F. nucleatum in stool, saliva, and serum samples of patients may aid in the diagnosis, risk assessment, and prognosis monitoring of GI malignancies. This editorial systematically describes the biological roles and mechanisms of F. nucleatum in GI malignancies focusing on the application of F. nucleatum as a biomarker in the diagnosis and prognosis of GI malignancies to promote the clinical translation of F. nucleatum and GI tumors-related research.

Prognostic impact of oral microbiome on survival of malignancies: a systematic review and meta-analysis

BACKGROUND

Recent studies have shown that there exists a significant correlation between oral microbiome and the occurrence of malignancies. However, the prognostic significance of oral microbiome for cancer patients remains unclear. The purpose of this meta-analysis is to evaluate the impact of oral microbiome on the survival of patients with malignant neoplasms.

METHODS

We conducted a thorough literature search of PubMed, Embase, and Cochrane Library databases until September 2022. The hazard ratio (HR) with a corresponding 95% confidence interval (CI) was analyzed using Review Manager 5.4 software for survival outcomes, including overall survival (OS), disease-specific survival (DSS), progression-free survival (PFS), and disease-free survival (DFS).

RESULTS

A total of 15 studies, covering 5191 samples with various types of cancers, were selected based on specified inclusion and exclusion criteria. In both univariate and multivariate analysis, patients with low diversity of the oral microbiome, or those with Fusobacterium-high/positive, or P. gingivalis positive in cancer tissue displayed poorer OS (univariate HR = 1.74; 95% CI 1.15-2.62; P = 0.009; multivariate HR = 1.56; 95% CI 1.07-2.27; P = 0.02), DSS (univariate HR = 2.06; 95% CI 1.50-2.84; P < 0.00001; multivariate HR = 1.80; 95% CI 1.48-2.20; P < 0.00001), and PFS/DFS (univariate HR = 2.00; 95% CI 1.12-3.58; P = 0.002; multivariate HR = 1.78; 95% CI 1.05-3.02; P = 0.003). Subgroup analysis revealed that Fusobacterium positive or high abundance in cancer tissues was associated with poor OS in multivariate analysis but had no statistical differences in PFS or DFS in univariate and multivariate analysis. Additionally, P. gingivalis positive in cancer tissue was also associated with worse OS.

CONCLUSIONS

Our meta-analysis suggests that the composition of the oral microbiome may play a significant role in predicting survival outcomes for cancer patients.

Tumor-associated microbiome features of metastatic colorectal cancer and clinical implications

Background

Colon microbiome composition contributes to the pathogenesis of colorectal cancer (CRC) and prognosis. We analyzed 16S rRNA sequencing data from tumor samples of patients with metastatic CRC and determined the clinical implications.

Materials and methods

We enrolled 133 patients with metastatic CRC at St. Vincent Hospital in Korea. The V3-V4 regions of the 16S rRNA gene from the tumor DNA were amplified, sequenced on an Illumina MiSeq, and analyzed using the DADA2 package.

Results

After excluding samples that retained <5% of the total reads after merging, 120 samples were analyzed. The median age of patients was 63 years (range, 34-82 years), and 76 patients (63.3%) were male. The primary cancer sites were the right colon (27.5%), left colon (30.8%), and rectum (41.7%). All subjects received 5-fluouracil-based systemic chemotherapy. After removing genera with <1% of the total reads in each patient, 523 genera were identified. Rectal origin, high CEA level (≥10 ng/mL), and presence of lung metastasis showed higher richness. Survival analysis revealed that the presence of Prevotella (p = 0.052), Fusobacterium (p = 0.002), Selenomonas (p<0.001), Fretibacterium (p = 0.001), Porphyromonas (p = 0.007), Peptostreptococcus (p = 0.002), and Leptotrichia (p = 0.003) were associated with short overall survival (OS, <24 months), while the presence of Sphingomonas was associated with long OS (p = 0.070). From the multivariate analysis, the presence of Selenomonas (hazard ratio [HR], 6.35; 95% confidence interval [CI], 2.38-16.97; p<0.001) was associated with poor prognosis along with high CEA level.

Conclusion

Tumor microbiome features may be useful prognostic biomarkers for metastatic CRC.

Association of Fusobacterium nucleatum infection with the clinicopathological characteristics in colorectal cancer patients

BACKGROUND

Colorectal cancer (CRC) is a global health problem. The gut microbiome is now recognized as an important underlying factor to the initiation and progression of CRC. Fusobacterium nucleatum (FN) is one of the most studied bacteria in the aetiology of CRC. This study provided cohort evidence on the association of FN infection with clinicopathologic features in CRC patients.

METHODS

We analysed the cancerous and adjacent non-cancerous formalin-fixed paraffin embedded (FFPE) tissue of 83 CRC patients from a single medical centre in Malaysia. TaqMan probe-based qPCR targeting the 16S rRNA gene was used to detect the presence of FN in the extracted FFPE DNA. The differences in FN expression between cancer and non-cancer tissues were evaluated. Association studies between FN infection in the tumour and relative FN abundance with available clinical data were conducted.

RESULTS

FN was more abundant in the cancerous tissue compared to non-cancerous tissue (p = 0.0025). FN infection in the tumour was significantly associated with lymph node metastasis (p = 0.047) and cancer staging (p = 0.032), but not with other clinicopathologic variables. In double-positive patients where FN was detected in both cancerous and non-cancerous tissue, the expression fold-change of FN, calculated using 2-ΔΔCT formula, was significantly higher in patients with tumour size equal to or greater than 5 cm (p = 0.033) and in KRAS-mutated patients (p = 0.046).

CONCLUSIONS

FN is enriched in CRC tumour tissue and is associated with tumour size, lymph node metastasis, cancer staging, and KRAS mutation in this single-centre small cohort study.

Spatial transcriptomic analysis reveals local effects of intratumoral fusobacterial infection on DNA damage and immune signaling in rectal cancer

Mucinous colorectal cancer (CRC) is a common histological subtype of colorectal adenocarcinoma, associated with a poor response to chemoradiotherapy. The commensal facultative anaerobes fusobacteria, have been associated with poor prognosis specifically in mesenchymal CRC. Interestingly, fusobacterial infection is especially prevalent in mucinous CRC. The objective of this study was therefore to increase our understanding of beneficial and detrimental effects of fusobacterial infection, by contrasting host cell signaling and immune responses in areas of high vs. low infection, using mucinous rectal cancer as a clinically relevant example. We employed spatial transcriptomic profiling of 106 regions of interest from 8 mucinous rectal cancer samples to study gene expression in the epithelial and immune segments across regions of high versus low fusobacterial infection. Fusobacteria high regions were associated with increased oxidative stress, DNA damage, and P53 signaling. Meanwhile regions of low fusobacterial prevalence were characterized by elevated JAK-STAT, Il-17, Il-1, chemokine and TNF signaling. Immune masks within fusobacterial high regions were characterized by elevated proportions of cytotoxic (CD8+) T cells (p = 0.037), natural killer (NK) cells (p < 0.001), B-cells (p < 0.001), and gamma delta T cells (p = 0.003). Meanwhile, fusobacteria low regions were associated with significantly greater M2 macrophage (p < 0.001), fibroblast (p < 0.001), pericyte (p = 0.002), and endothelial (p < 0.001) counts.

Fusobacterium nucleatum Load Correlates with KRAS Mutation and Sessile Serrated Pathogenesis in Colorectal Adenocarcinoma

Fusobacterium nucleatum (Fn) has been frequently detected in colorectal cancer. A high load of Fn has been associated with subtypes of colorectal cancers, located in the proximal colon, exhibiting microsatellite instability-high (MSI-H), MLH1 promoter hypermethylation, the CpG island hypermethylation phenotype-high, or BRAF mutation in some studies. Although these features characterize the sessile serrated pathway (SSP) of colon cancers, other studies have shown that Fn infection is associated with KRAS mutations mainly characteristic of non-serrated neoplasia. It is also not clear at what point the association of Fn infection with these genomic alterations is established during colorectal carcinogenesis. Here we show that MSI-H, MLH1 hypermethylation, BRAF mutation or KRAS mutations were independently associated with Fn infection in colorectal cancer. On the other hand, increasing Fn copy number in tissues was associated with increased probability to exhibit MSI-H, MLH1 hypermethylation or BRAF mutations but not KRAS mutations in colorectal cancer. We also show that Fn load was significantly less than that of colorectal cancer and no association was detected between BRAF/KRAS mutations or MLH1 hypermethylation and Fn infection in adenomas. Our combined data suggest that increasing loads of Fn during and/or after adenomacarcinoma transition might promote SSP but not KRAS-driven colorectal carcinogenesis. Alternatively, Fn preferentially colonizes colorectal cancers with SSP and KRAS mutations but can expand more in colorectal cancers with SSP.

SIGNIFICANCE

The authors demonstrated that Fn is enriched in colorectal cancers exhibiting the SSP phenotype, and in colorectal cancers carrying KRAS mutations. Fn infection should be considered as a candidate risk factor specific to colorectal cancers with the SSP phenotype and with KRAS mutations.

Microbiota composition and its impact on DNA methylation in colorectal cancer

Colorectal cancer is a complex disease resulting from the interaction of genetics, epigenetics, and environmental factors. DNA methylation is frequently found in tumor suppressor genes to promote cancer development. Several factors are associated with changes in the DNA methylation pattern, and recently, the gastrointestinal microbiota could be associated with this epigenetic change. The predominant phyla in gut microbiota are Firmicutes and Bacteroidetes; however, an enrichment of Bacteroides fragilis, Fusobacterium nucleatum, and Streptococcus bovis, among others, has been reported in colorectal cancer, although the composition could be influenced by several factors, including diet, age, sex, and cancer stage. Fusobacterium nucleatum, a gram-negative anaerobic bacillus, is mainly associated with colorectal cancer patients positive for the CpG island methylator phenotype, although hypermethylation in genes such as MLH1, CDKN2A, MTSS1, RBM38, PKD1, PTPRT, and EYA4 has also been described. Moreover, Hungatella hathewayi, a gram-positive, rod-shaped bacterium, is related to hypermethylation in SOX11, THBD, SFRP2, GATA5, ESR1, EYA4, CDX2, and APC genes. The underlying epigenetic mechanism is unclear, although it could be implicated in the regulation of DNA methyltransferases, enzymes that catalyze the transfer of a methyl group on cytosine of CpG sites. Since DNA methylation is a reversible event, changes in gut microbiota could modulate the gene expression through DNA methylation and improve the colorectal cancer prognosis.

Three specific gut bacteria in the occurrence and development of colorectal cancer: a concerted effort

Colorectal cancer (CRC), which develops from the gradual evolution of tubular adenomas and serrated polyps in the colon and rectum, has a poor prognosis and a high mortality rate. In addition to genetics, lifestyle, and chronic diseases, intestinal integrity and microbiota (which facilitate digestion, metabolism, and immune regulation) could promote CRC development. For example, enterotoxigenic Bacteroides fragilis, genotoxic Escherichia coli (pks+ E. coli), and Fusobacterium nucleatum, members of the intestinal microbiota, are highly correlated in CRC. This review describes the roles and mechanisms of these three bacteria in CRC development. Their interaction during CRC initiation and progression has also been proposed. Our view is that in the precancerous stage of colorectal cancer, ETBF causes inflammation, leading to potential changes in intestinal ecology that may provide the basic conditions for pks+ E. coli colonization and induction of oncogenic mutations, when cancerous intestinal epithelial cells can further recruit F. nucleatum to colonise the lesion site and F. nucleatum may contribute to CRC advancement by primarily the development of cancer cells, stemization, and proliferation, which could create new and tailored preventive, screening and therapeutic interventions. However, there is the most dominant microbiota in each stage of CRC development, not neglecting the possibility that two or even all three bacteria could be engaged at any stage of the disease. The relationship between the associated gut microbiota and CRC development may provide important information for therapeutic strategies to assess the potential use of the associated gut microbiota in CRC studies, antibiotic therapy, and prevention strategies.

Oncomicrobial Community Profiling Identifies Clinicomolecular and Prognostic Subtypes of Colorectal Cancer

BACKGROUND & AIMS

Dysbiosis of gut microbiota is linked to the development of colorectal cancer (CRC). However, microbiota-based stratification of CRC tissue and how this relates to clinicomolecular characteristics and prognosis remains to be clarified.

METHODS

Tumor and normal mucosa from 423 patients with stage I to IV CRC were profiled by bacterial 16S rRNA gene sequencing. Tumors were characterized for microsatellite instability (MSI), CpG island methylator phenotype (CIMP), APC, BRAF, KRAS, PIK3CA, FBXW7, SMAD4, and TP53 mutations, subsets for chromosome instability (CIN), mutation signatures, and consensus molecular subtypes (CMS). Microbial clusters were validated in an independent cohort of 293 stage II/III tumors.

RESULTS

Tumors reproducibly stratified into 3 oncomicrobial community subtypes (OCSs) with distinguishing features: OCS1 (Fusobacterium/oral pathogens, proteolytic, 21%), right-sided, high-grade, MSI-high, CIMP-positive, CMS1, BRAF V600E, and FBXW7 mutated; OCS2 (Firmicutes/Bacteroidetes, saccharolytic, 44%), and OCS3 (Escherichia/Pseudescherichia/Shigella, fatty acid β-oxidation, 35%) both left-sided and exhibiting CIN. OCS1 was associated with MSI-related mutation signatures (SBS15, SBS20, ID2, and ID7) and OCS2 and OCS3 with SBS18 related to damage by reactive oxygen species. Among stage II/III patients, OCS1 and OCS3 both had poorer overall survival compared with OCS2 for microsatellite stable tumors (multivariate hazard ratio [HR], 1.85; 95% confidence interval [CI], 1.15-2.99; P = .012; and HR, 1.52; 95% CI 1.01-2.29; P = .044, respectively) and left-sided tumors (multivariate HR, 2.66; 95% CI, 1.45-4.86; P = .002; and HR, 1.76; 95% CI, 1.03-3.02; P = .039, respectively).

CONCLUSIONS

OCS classification stratified CRCs into 3 distinct subgroups with different clinicomolecular features and outcomes. Our findings provide a framework for a microbiota-based stratification of CRC to refine prognostication and to inform the development of microbiota-targeted interventions.

Increased Fusobacterium tumoural abundance affects immunogenicity in mucinous colorectal cancer and may be associated with improved clinical outcome

There is currently an urgent need to identify factors predictive of immunogenicity in colorectal cancer (CRC). Mucinous CRC is a distinct histological subtype of CRC, associated with a poor response to chemotherapy. Recent evidence suggests the commensal facultative anaerobe Fusobacterium may be especially prevalent in mucinous CRC. The objectives of this study were to assess the association of Fusobacterium abundance with immune cell composition and prognosis in mucinous CRC. Our study included two independent colorectal cancer patient cohorts, The Cancer Genome Atlas (TCGA) cohort, and a cohort of rectal cancers from the Beaumont RCSI Cancer Centre (BRCC). Multiplexed immunofluorescence staining of a tumour microarray (TMA) from the BRCC cohort was undertaken using Cell DIVE technology. Our cohorts included 87 cases (13.3%) of mucinous and 565 cases (86.7%) of non-mucinous CRC. Mucinous CRC in the TCGA dataset was associated with an increased proportion of CD8 + lymphocytes (p = 0.018), regulatory T-cells (p = 0.001) and M2 macrophages (p = 0.001). In the BRCC cohort, mucinous RC was associated with enhanced CD8 + lymphocyte (p = 0.022), regulatory T-cell (p = 0.047), and B-cell (p = 0.025) counts. High Fusobacterium abundance was associated with an increased proportion of CD4 + lymphocytes (p = 0.031) and M1 macrophages (p = 0.006), whilst M2 macrophages (p = 0.043) were under-represented in this cohort. Patients with increased Fusobacterium relative abundance in our mucinous CRC TCGA cohort tended to have better clinical outcomes (DSS: likelihood ratio p = 0.04, logrank p = 0.052). Fusobacterium abundance may be associated with improved outcomes in mucinous CRC, possibly due to a modulatory effect on the host immune response. KEY MESSAGES: • Increased Fusobacterium relative abundance was not found to be associated with microsatellite instability in mucinous CRC. • Increased Fusobacterium relative abundance was associated with an M2/M1 macrophage switch, which is especially significant in mucinous CRC, where M2 macrophages are overexpressed. • Increased Fusobacterium relative abundance was associated with a significant improvement in disease specific survival in mucinous CRC. • Our findings were validated at a protein level within our own in house mucinous and non-mucinous rectal cancer cohorts.

Gut microbiota, an emergent target to shape the efficiency of cancer therapy

It is now well-acknowledged that microbiota has a profound influence on both human health and illness. The gut microbiota has recently come to light as a crucial element that influences cancer through a variety of mechanisms. The connections between the microbiome and cancer therapy are further highlighted by a number of preclinical and clinical evidence, suggesting that these complicated interactions may vary by cancer type, treatment, or even by tumor stage. The paradoxical relationship between gut microbiota and cancer therapies is that in some cancers, the gut microbiota may be necessary to maintain therapeutic efficacy, whereas, in other cancers, gut microbiota depletion significantly increases efficacy. Actually, mounting research has shown that the gut microbiota plays a crucial role in regulating the host immune response and boosting the efficacy of anticancer medications like chemotherapy and immunotherapy. Therefore, gut microbiota modulation, which aims to restore gut microbial balance, is a viable technique for cancer prevention and therapy given the expanding understanding of how the gut microbiome regulates treatment response and contributes to carcinogenesis. This review will provide an outline of the gut microbiota's role in health and disease, along with a summary of the most recent research on how it may influence the effectiveness of various anticancer medicines and affect the growth of cancer. This study will next cover the newly developed microbiota-targeting strategies including prebiotics, probiotics, and fecal microbiota transplantation (FMT) to enhance anticancer therapy effectiveness, given its significance.

Fusobacterium nucleatum and its associated systemic diseases: epidemiologic studies and possible mechanisms

Background

Fusobacterium nucleatum (F. nucleatum) is an anaerobic oral commensal and the major coaggregation bridge organism linking early and late colonisers. In recent years, a large number of studies suggest that F. nucleatum is closely related to the development of various systemic diseases, such as cardiovascular diseases, adverse pregnancy outcomes, inflammatory bowel diseases, cancer, Alzheimer's disease, respiratory infection, rheumatoid arthritis, etc.

Objective

To review the effect of F. nucleatum on systemic diseases and its possible pathogenesis and to open new avenues for prevention and treatment of F. nucleatum-associated systemic diseases.

Design

The research included every article published up to July 2022 featuring the keywords 'Systemic diseases' OR 'Atherosclerotic cardiovascular diseases' OR 'Atherosclerosis' OR 'Adverse pregnancy outcomes' OR 'Inflammatory bowel disease' OR 'Ulcerative colitis' OR 'Crohn’s disease' OR 'Cancers' OR 'Oral squamous cell carcinomas' OR 'Gastrointestinal cancers' OR 'Colorectal cancer' OR 'Breast cancer' OR 'Genitourinary cancers' OR 'Alzheimer’s disease ' OR 'Rheumatoid arthritis' OR 'Respiratory diseases' AND 'Fusobacterium nucleatum' OR 'Periodontal pathogen' OR 'Oral microbiota' OR 'Porphyromonas gingivalis' and was conducted in the major medical databases.

Results

F. nucleatum can induce immune response and inflammation in the body through direct or indirect pathways, and thus affect the occurrence and development of systemic diseases. Only by continuing to investigate the pathogenic lifestyles of F. nucleatum will we discover the divergent pathways that may be leveraged for diagnostic, preventive and therapeutic purposes.

The Microbiome's Influence on Head and Neck Cancers

PURPOSE OF REVIEW

Head and neck tumors (HNC) rank sixth among cancers worldwide. Due to their late diagnosis and poor prognosis, they are a clinical challenge. However, recent years have seen a dynamic development of science on the microbiome. The aim of the study is to discuss the role of the microbiome in HNC, the impact of the microbiome on oncogenesis, the course of the disease, as well as on treatment, and its toxicity.

RECENT FINDINGS

The microbiome's influence on oncogenesis, the course of the disease, and the effectiveness of oncological treatment have been confirmed in cancers of the colon, pancreas, lungs, and prostate. There is no solid literature on HNC. Many studies indicate disruption of the oral microbiome and periodontal disease as potential cancer risk factors. Disruption of the microbiome increases radiotherapy's toxicity, intensifying radiation reactions. The microbiome plays an important role in cancer. It is a new target in research into new therapies. It may also be a prognostic marker of cancer development. Changes in the composition of the microbiome modulate the effectiveness of oncological treatment. More research is needed on the microbiome and its effects on HNC.

Enhanced Fusobacterium nucleatum Genetics Using Host DNA Methyltransferases To Bypass Restriction-Modification Systems

Bacterial restriction-modification (R-M) systems are a first-line immune defense against foreign DNA from viruses and other bacteria. While R-M systems are critical in maintaining genome integrity, R-M nucleases unfortunately present significant barriers to targeted genetic modification. Bacteria of the genus Fusobacterium are oral, Gram-negative, anaerobic, opportunistic pathogens that are implicated in the progression and severity of multiple cancers and tissue infections, yet our understanding of their direct roles in disease have been severely hindered by their genetic recalcitrance. Here, we demonstrate a path to overcome these barriers in Fusobacterium by using native DNA methylation as a host mimicry strategy to bypass R-M system cleavage of transformed plasmid DNA. We report the identification, characterization, and successful use of Fusobacterium nucleatum type II and III DNA methyltransferase (MTase) enzymes to produce a multifold increase in gene knockout efficiency in the strain Fusobacterium nucleatum subsp. nucleatum 23726, as well as the first system for efficient gene knockouts and complementations in F. nucleatum subsp. nucleatum 25586. We show plasmid protection can be accomplished in vitro with purified enzymes, as well as in vivo in an Escherichia coli host that constitutively expresses F. nucleatum subsp. nucleatum MTase enzymes. In summary, this proof-of-concept study characterizes specific MTases that are critical for bypassing R-M systems and has enhanced our understanding of enzyme combinations that could be used to genetically modify clinical isolates of Fusobacterium that have thus far been inaccessible to molecular characterization. IMPORTANCE Fusobacterium nucleatum is an oral opportunistic pathogen associated with diseases that include cancer and preterm birth. Our understanding of how this bacterium modulates human disease has been hindered by a lack of genetic systems. Here, we show that F. nucleatum DNA methyltransferase-modified plasmid DNA overcomes the transformation barrier and has allowed the development of a genetic system in a previously inaccessible strain. We present a strategy that could potentially be expanded to enable the genetic modification of highly recalcitrant strains, thereby fostering investigational studies to uncover novel host-pathogen interactions in Fusobacterium.

Tumour Colonisation of Parvimonas micra Is Associated with Decreased Survival in Colorectal Cancer Patients

Increasing evidence suggests that the gut microbiota may impact colorectal cancer (CRC) development and progression. In this study, the tumour colonisation of two CRC-associated bacteria, Parvimonas micra and Fusobacterium nucleatum, was studied in relation to patient survival in a cohort of 257 CRC patients. Colonisation of P. micra and F. nucleatum was analysed in fresh frozen tumour tissue (n = 112) and in faeces (n = 250) by qPCR. When analysing tumour tissues, both P. micra and F. nucleatum were found to be associated with decreased five-year cancer-specific survival, an association that remained significant in multivariable analysis for P. micra. Furthermore, we found significant associations of high levels of P. micra and F. nucleatum with tumour molecular characteristics, i.e., tumours mutated in BRAFV600E, and tumours of the MSI subtype. The analysis of faecal samples showed weaker associations with prognosis and tumour molecular characteristics. In conclusion, our findings support a novel association of tumour colonisation of P. micra with decreased patient survival. A better understanding of the role of the gut microbiota in CRC might contribute to the advancement of prognostic tools and new targets for therapy.

Fusobacterium nucleatum and colorectal cancer: From phenomenon to mechanism

Colorectal cancer(CRC) is the third most frequent malignant tumor. The gut microbiome acts as a vital component of CRC etiology. Fusobacterium nucleatum(Fn) is a key member of colorectal cancer-associated bacteria. But we lack a systematic and in-depth understanding on its role in CRC evolution. In this article, We reviewed the abundance changes and distribution of Fn in CRC occurrence and development, potential effect of Fn in the initiation of CRC, the source of intratumoral Fn and the cause of its tropism to CRC. In addition, We described the mechanism by which Fn promotes the malignant biological behavior of CRC, affects CRC response to therapy, and shapes the tumor immune microenvironment in great detail. Based on the relationship between Fn and CRC, we proposed strategies for CRC prevention and treatment, and discussed the feasibility and limitations of specific cases, to gain insights into further basic and clinical research in the future.

Clinical Significance of Fusobacterium nucleatum and Microsatellite Instability in Evaluating Colorectal Cancer Prognosis

Objective

Both genetic and microbial factors play important roles in colorectal cancer (CRC) development. The effects of Fusobacterium nucleatum (F. nucleatum) and microsatellite instability (MSI) on CRC prognosis require more clinical evidence. We aimed to investigate the role of F. nucleatum and MSI as biomarkers in predicting the prognosis of CRC.

Methods

CRC patients in various TNM stages were enrolled. MSI status and F. nucleatum were detected by immunohistochemical staining of formalin-fixed paraffin-embedded (FFPE) specimens. The associations between MSI status and F. nucleatum and clinical parameters were analyzed.

Results

MSI tumors were more frequently observed in the colon than in the rectum. Cancerous tissues had higher levels of F. nucleatum than adjacent noncancerous tissues. There were no significant differences in F. nucleatum abundance in different age, sex, tumor stage, location, and tumor marker groups. MSI status was associated with tumor location and stage. Survival analyses revealed that disease-free survival (DFS) was significantly longer in the F. nucleatum-negative, younger age, and TNM stage I-II groups (p< 0.05), and age, advanced TNM stage (III and IV), and F. nucleatum status were independent factors for poor prognosis. Multivariate Cox regression and receiver operating characteristic (ROC) curve analyses showed that conventional tumor biomarkers of CRC had more prognostic value than F. nucleatum and MSI.

Conclusion

Age, advanced TNM stage, and F. nucleatum positivity were independent factors of poor prognosis, suggesting that F. nucleatum and MSI may contribute to the identification of new strategies for the prevention and treatment of CRC.

Parvimonas micra is associated with tumour immune profiles in molecular subtypes of colorectal cancer

The importance of the tumour microbiome in different aspects of colorectal cancer (CRC) has been increasingly recognised, but many questions remain. The aim of this study was to explore the effect of specific CRC associated microbes on the tumour immune response, which has a considerable prognostic value in CRC. We applied specific qPCR to detect Parvimonas micra and Fusobacterium nucleatum in tumour tissues from an immunologically well-characterised cohort of 69 CRC patients. This cohort included detailed analyses of immune profiles based on flow cytometry and transcriptomics in tumour tissue and blood, along with comprehensive analyses of molecular subtypes. P. micra and F. nucleatum were detected in 24% and 64% of tumour tissues, respectively. We found a significant association of P. micra with high-grade tumours and tumours of CMS1 subtype. F. nucleatum was significantly associated with right-sided tumours, microsatellite instability, and CMS1 tumours. The immunological analyses revealed significant associations of P. micra with activated CD69⁺ T lymphocytes and increased antigen-presenting HLA-DR⁺ B lymphocytes. P. micra was also positively associated with M1 and M2 macrophage traits. The impact of P. micra tumour colonisation on the immune response was further assessed using transcriptomics in validation of our findings. No associations were found between F. nucleatum and immune profiles in this study. Our findings support novel associations between P. micra and the immune response in CRC. A better understanding of these interactions might help to identify important predictive and prognostic tools as well as new targets for therapy.

Integrated analysis of intestinal microbiota and host gene expression in colorectal cancer patients

Introduction. Colorectal cancer (CRC) is one of the most common cancers and poses heavy burden on global health. The relationship between mucosal microbiome composition and colorectal gene expression are rarely studied. In this study, we integrated transcriptome data with microbiome data to investigate the relationship between them in colorectal cancer patients.Gap statement. Previous studies have identified the contribution of gut microbiota and DEGs to the pathogenesis of CRC, but the relationship between mucosal microbiome composition and colorectal gene expression are rarely studied.Aim. In this study, we integrated transcriptome data with microbiome data to investigate the relationship between mucosal microbiome composition and colorectal gene expression.Methodology. First, three independent CRC gene expression profiles (GSE184093, GSE156355 and GSE146587) from Gene Expression Omnibus (GEO) were used to identify differentially expressed genes (DEGs). Second, another dataset (GSE163366) was used to analyse gut mucosal microbiome differential abundance. GO (Gene Ontology) function and KEGG (Kyoto Encyclopaedia of Genes and Genomes) pathway enrichment analyses of the DEGs were performed. Protein-protein interactions (PPIs) of the DEGs were constructed. The Spearman correlation analysis was computed between host DEGs and gut microbiome abundance data.Results. A total of 1036 upregulated DEGs and 1194 downregulated DEGs between noncancerous tissues and cancerous tissues were identified based on the analysis. One significant module with a score 37.65 was selected out via MCODE including 41 upregulated DEGs, which are were mostly enriched in two pathways, including microtubule binding and tubulin binding. In particular, significant negative correlations are prevalent between Fusobacterium and the 41 DEGs with the correlation ranging between -0.54 and -0.35, and there commonly exist significant positive correlations between Blautia and the 41 DEGs with the correlation ranging between 0.42 and 0.54, indicating that Fusobacterium and Blautia are two of the most important microbes interacting with the gene regulation.Conclusion. Our results demonstrate significant correlation between some gut microbes and DEGs, providing a comprehensive bioinformatics analysis of them for future investigation into the molecular mechanisms and biomarkers.

Patients with mesenchymal tumours and high Fusobacteriales prevalence have worse prognosis in colorectal cancer (CRC)

OBJECTIVES

Transcriptomic-based subtyping, consensus molecular subtyping (CMS) and colorectal cancer intrinsic subtyping (CRIS) identify a patient subpopulation with mesenchymal traits (CMS4/CRIS-B) and poorer outcome. Here, we investigated the relationship between prevalence of Fusobacterium nucleatum (Fn) and Fusobacteriales, CMS/CRIS subtyping, cell type composition, immune infiltrates and host contexture to refine patient stratification and to identify druggable context-specific vulnerabilities.

DESIGN

We coupled cell culture experiments with characterisation of Fn/Fusobacteriales prevalence and host biology/microenviroment in tumours from two independent colorectal cancer patient cohorts (Taxonomy: n=140, colon and rectal cases of The Cancer Genome Atlas (TCGA-COAD-READ) cohort: n=605).

RESULTS

In vitro, Fn infection induced inflammation via nuclear factor kappa-light-chain-enhancer of activated B cells/tumour necrosis factor alpha in HCT116 and HT29 cancer cell lines. In patients, high Fn/Fusobacteriales were found in CMS1, microsatellite unstable () tumours, with infiltration of M1 macrophages, reduced M2 macrophages, and high interleukin (IL)-6/IL-8/IL-1β signalling. Analysis of the Taxonomy cohort suggested that Fn was prognostic for CMS4/CRIS-B patients, despite having lower Fn load than CMS1 patients. In the TCGA-COAD-READ cohort, we likewise identified a differential association between Fusobacteriales relative abundance and outcome when stratifying patients in mesenchymal (either CMS4 and/or CRIS-B) versus non-mesenchymal (neither CMS4 nor CRIS-B). Patients with mesenchymal tumours and high Fusobacteriales had approximately twofold higher risk of worse outcome. These associations were null in non-mesenchymal patients. Modelling the three-way association between Fusobacteriales prevalence, molecular subtyping and host contexture with logistic models with an interaction term disentangled the pathogen-host signalling relationship and identified aberrations (including NOTCH, CSF1-3 and IL-6/IL-8) as candidate targets.

CONCLUSION

This study identifies CMS4/CRIS-B patients with high Fn/Fusobacteriales prevalence as a high-risk subpopulation that may benefit from therapeutics targeting mesenchymal biology.

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.

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.

The gut microbiota can orchestrate the signaling pathways in colorectal cancer

Current evidence suggests that bacteria contribute to the development of certain cancers, such as colorectal cancer (CRC), partly by stimulating chronic inflammation. However, little is known about the bacterial impact on molecular pathways in CRC. Recent studies have demonstrated how specific bacteria can influence the major CRC-related pathways, i.e., Wnt, PI3K-Akt, MAPK, TGF-β, EGFR, mTOR, and p53. In order to advance the current understanding and facilitate the choice of pathways to investigate, we have systematically collected and summarized the current knowledge within bacterial altered major pathways in CRC. Several pro-tumorigenic and anti-tumorigenic bacterial species and their respective metabolites interfere with the major signaling pathways addressed in this review. Not surprisingly, some of these studies investigated known CRC drivers, such as Escherichia coli, Fusobacterium nucleatum, and Bacteroides fragilis. Interestingly, some metabolites produced by bacterial species typically considered pathogenic, e.g., Vibrio cholera, displayed anti-tumorigenic activities, emphasizing the caution needed when classifying healthy and unhealthy microorganisms. The results collectively emphasize the complexity of the relationship between the microbiota and the tumorigenesis of CRC, and future studies should verify these findings in more realistic models, such as organoids, which constitute a promising platform. Moreover, future trials should investigate the clinical potential of preventive modulation of the gut microbiota regarding CRC development.

Vitamin D and colorectal cancer: Chemopreventive perspectives through the gut microbiota and the immune system

Vitamin D and its receptor are involved in health and diseases through multiple mechanisms including the immune system and gut microbiota modulations. Gut microbiota variations have huge implications in intestinal and extra-intestinal disorders such as colorectal cancer (CRC). This review highlights the preventive role of vitamin D in colorectal tumorigenesis through the effects on the immune system and gut microbiota modulation. The different associations between vitamin D, gut microbial homeostasis, immune system, and CRC, are dissected. Vitamin D is supposed to exert several chemopreventive effects on CRC including direct antineoplastic mechanisms, the effects on the immune system, and gut microbiota modulation. Large clinical studies with a randomized design, are required to confirm the role of vitamin D in CRC, confirming its key role in the complex interplay between the gut immune system and microbiota.

Serrated neoplasia in the colorectum: gut microbiota and molecular pathways

Colorectal cancer (CRC) is a heterogeneous disease with different gene expression patterns. There are two major colorectal carcinogenesis pathways: conventional adenoma-carcinoma pathway and alternative serrated neoplasia pathway. Apart from the conventional pathway that is typically initiated by characteristic APC mutation and chromosomal instability, the serrated neoplasia pathway is mainly characterized by mutations of BRAF or KRAS, microsatellite instability (MSI), and CpG island methylator phenotype (CIMP). Despite the malignant potential of serrated lesions, they can be easily overlooked during endoscopy screening and even in pathological assessment due to its anatomical location, morphology, and histological features. It has been shown that environmental factors especially the gut microbial composition play a key role in CRC pathogenesis. Thus, the preferential localization of serrated lesions in specific intestine areas suggest that niche-specific microbiota composition might intertwined with host genetic perturbations during the development of serrated lesions. Although serrated lesions and conventional adenomas are biologically different, most studies have focused on conventional adenomas, while the pathophysiology and role of microorganisms in the development of serrated lesions remain elusive. In this review, we discuss on the role of gut microbiota in the serrated neoplasia pathway of colorectal carcinogenesis and its specific clinical and molecular features, and summarize the potential mechanisms involved.

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.

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.

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.

Fusobacterium nucleatum and oral cancer: a critical review

There is a growing level of interest in the potential role inflammation has on the initiation and progression of malignancy. Notable examples include Helicobacter pylori-mediated inflammation in gastric cancer and more recently Fusobacterium nucleatum-mediated inflammation in colorectal cancer. Fusobacterium nucleatum is a Gram-negative anaerobic bacterium that was first isolated from the oral cavity and identified as a periodontal pathogen. Biofilms on oral squamous cell carcinomas are enriched with anaerobic periodontal pathogens, including F. nucleatum, which has prompted hypotheses that this bacterium could contribute to oral cancer development. Recent studies have demonstrated that F. nucleatum can promote cancer by several mechanisms; activation of cell proliferation, promotion of cellular invasion, induction of chronic inflammation and immune evasion. This review provides an update on the association between F. nucleatum and oral carcinogenesis, and provides insights into the possible mechanisms underlying it.

Association between Fusobacterium nucleatum and patient prognosis in metastatic colon cancer

Recent evidence suggests that Fusobacterium nucleatum (Fn) is associated with the development and progression of colorectal cancer. We aimed to delineate the clinical implications of Fn in metastatic colon cancer. We performed quantitative polymerase chain reaction (qPCR) using DNA samples from synchronous metastatic colon cancer patients with either formalin-fixed paraffin-embedded (FFPE) archival primary site tumor samples or fresh colon tissues. Progression-free survival (PFS)1 and PFS2 were defined as PFS of first- and second-line palliative settings. qPCR for Fn was successfully performed using 112 samples (FFPE, n = 61; fresh tissue, n = 51). Forty-one and 68 patients had right-sided and left-sided colon cancer, respectively. Patients with Fn enriched right-sided colon cancers had shorter PFS1 (9.7 vs. 11.2 months) than the other subgroups (HR 3.54, 95% confidence interval [CI] 1.05–11.99; P = 0.04). Fn positive right-sided colon was also associated with shorter PFS2 (3.7 vs. 6.7 months; HR 2.34, 95% CI 0.69–7.91; P = 0.04). In the univariate analysis, PFS1 was affected by differentiation and Fn positive right-sided colon cancer. The multivariate analysis showed that differentiation (HR 2.68, 95% CI 1.40–5.14, P = 0.01) and Fn positive right-sided colon (HR 0.40, 95% CI 0.18–0.88, P = 0.02) were associated with PFS1. Fn enrichment in right sided colon was not associated with overall survival (OS). Fn enrichment has significantly worse prognosis in terms of PFS1 and PFS2 in patients with right-sided metastatic colon cancers.

Gut Microbiota Dysbiosis Drives the Development of Colorectal Cancer

BACKGROUND

The gut microbiota is a diverse community of microbes that maintain the stability of the intestinal environment. Dysbiosis of the gut microbiota has been linked to gastrointestinal diseases, such as colorectal cancer (CRC) - a leading cause of death for cancer patients.

SUMMARY

Candidate pathogens have been identified using bacterial culture and high-throughput sequencing techniques. Currently, there is evidence to show that specific intestinal microbes drive CRC development and progression, yet their pathogenic mechanisms are still unclear. Key Messages: In this review, we describe the known healthy gut microbiota and its changes in CRC. We especially focus on exploring the pathogenic mechanisms of gut microbiota dysbiosis in CRC. This is crucial for explaining how gut microbiota dysbiosis drives the process of colorectal carcinogenesis and tumor progression. Evaluation of changes in the gut microbiota during CRC development and progression offers a new strategy for the diagnosis and treatment of this disease.

Gut microbiota-derived metabolites in CRC progression and causation

BACKGROUND

Based on recent research reports, dysbiosis and improper concentrations of microbial metabolites in the gut may result into the carcinogenesis of colorectal cancer. Recent advancement also highlights the involvement of bacteria and their secreted metabolites in the cancer causation. Gut microbial metabolites are functional output of the host-microbiota interactions and produced by anaerobic fermentation of food components in the diet. They contribute to influence variety of biological mechanisms including inflammation, cell signaling, cell-cycle disruption which are majorly disrupted in carcinogenic activities.

PURPOSE

In this review, we intend to discuss recent updates and possible molecular mechanisms to provide the role of bacterial metabolites, gut bacteria and diet in the colorectal carcinogenesis. Recent evidences have proposed the role of bacteria, such as Fusobacterium nucleaturm, Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis and Clostridium septicum, in the carcinogenesis of CRC. Metagenomic study confirmed that these bacteria are in increased abundance in CRC patient as compared to healthy individuals and can cause inflammation and DNA damage which can lead to development of cancer. These bacteria produce metabolites, such as secondary bile salts from primary bile salts, hydrogen sulfide, trimethylamine-N-oxide (TMAO), which are likely to promote inflammation and subsequently cancer development.

CONCLUSION

Recent studies suggest that gut microbiota-derived metabolites have a role in CRC progression and causation and hence, could be implicated in CRC diagnosis, prognosis and therapy.

Profiling of host genetic alterations and intra-tumor microbiomes in colorectal cancer

Some bacteria are symbiotic in tumor tissues, and metabolites of several bacterial species have been found to cause DNA damage. However, to date, the association between bacteria and host genetic alterations in colorectal cancer (CRC) has not been fully investigated. We evaluated the association between the intra-tumor microbiome and host genetic alterations in 29 Japanese CRC patients. The tumor and non-tumor tissues were extracted from the patients, and 16S rRNA genes were sequenced for each sample. We identified enriched bacteria in tumor and non-tumor tissues. Some bacteria, such as Fusobacterium, which is already known to be enriched in CRC, were found to be enriched in tumor tissues. Interestingly, Bacteroides, which is also known to be enriched in CRC, was enriched in non-tumor tissues. Furthermore, it was shown that certain bacteria that often coexist within tumor tissue were enriched in the presence of a mutated gene or signal pathway with mutated genes in the host cells. Fusobacterium was associated with many mutated genes, as well as cell cycle-related pathways including mutated genes. In addition, the patients with a high abundance of Campylobacter were suggested to be associated with mutational signature 3 indicating failure of double-strand DNA break repairs. These results suggest that CRC development may be partly caused by DNA damage caused by substances released by bacterial infection. Taken together, the identification of distinct gut microbiome patterns and their host specific genetic alterations might facilitate targeted interventions, such as modulation of the microbiome in addition to anticancer agents or immunotherapy.

Proliferative Effect of FadA Recombinant Protein from Fusobacterium nucleatum on SW480 Colorectal Cancer Cell Line

BACKGROUND AND AIM

Colorectal Cancer (CRC) is one of the most frequent cancers diagnosed in both men and women worldwide. Fusobacterium nucleatum adhesin A (FadA) has an important potential factor in the development or progression of CRC. The aim of the present study was to evaluate the proliferative effect of recombinant FadA on SW480 colorectal cancer cell line.

MATERIALS AND METHODS

The recombinant pET21(b)-fadA plasmid was synthesized and transformed into competent E.coli DH5α. In the next step, induction and expression of recombinant FadA were carried out in E. coli BL21 (DE3) competent cells. Expression and purification of protein were successfully done and it was analyzed and confirmed by SDS-PAGE and western blotting. The proliferative effect of purified FadA on SW480 CRC cell line was evaluated using MTT assay and cell counting methods.

RESULTS

Visualization of the specific band isolated from the linear plasmid on the agarose gel confirmed the presence of the desired gene. After electrophoresis and Coomassie blue staining, the protein of interest with an approximate molecular weight of 13KDa was detected. The MTT assay, similar to cell counting methods, revealed that FadA dose and time-dependently promoted SW480 cell growth and proliferation in 24, 48 and 72 hours.

CONCLUSION

The results showed that FadA stimulates proliferation of SW480 colorectal cancer cell line with a dose and time-dependent manner.

The dysbiosis signature of Fusobacterium nucleatum in colorectal cancer-cause or consequences? A systematic review

Colorectal cancer (CRC) is the third most common cause of cancer globally and the fourth attributable cause of mortality and morbidity due to cancer. An emerging factor contributing to CRC is the gut microbiota and the cellular changes associated with it. Further insights on this may help in the prevention, diagnosis and new therapeutic approaches to colorectal cancer. In most cases of CRC, genetic factors appear to contribute less to its aetiology than environmental and epigenetic factors; therefore, it may be important to investigate these environmental factors, their effects, and the mechanisms that may contribute to this cancer. The gut microbiota has recently been highlighted as a potential risk factor that may affect the structural components of the tumor microenvironment, as well as free radical and enzymatic metabolites directly, or indirectly. Many studies have reported changes in the gut microbiota of patients with colorectal cancer. What is controversial is whether the cancer is the cause or consequence of the change in the microbiota. There is strong evidence supporting both possibilities. The presence of Fusobacterium nucleatum in human colorectal specimens has been demonstrated by RNA-sequencing. F. nucleatum has been shown to express high levels of virulence factors such as FadA, Fap2 and MORN2 proteins. Our review of the published data suggest that F. nucleatum may be a prognostic biomarker of CRC risk, and hence raises the potential of antibiotic treatment of F. nucleatum for the prevention of CRC.

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 tumor 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 presence of F. nucleatum in the CRC. However, further studies are needed to verify this relationship.

Gastrointestinal cancers: the role of microbiota in carcinogenesis and the role of probiotics and microbiota in anti-cancer therapy efficacy

The gut epithelium is a habitat of a variety of microorganisms, including bacteria, fungi, viruses and Archaea. With the advent of sophisticated molecular techniques and bioinformatics tools, more information on the composition and thus function of gut microbiota was revealed. The gut microbiota as an integral part of the intestinal barrier has been shown to be involved in shaping the mucosal innate and adaptive immune response and to provide protection against pathogens. Consequently, a set of biochemical signals exchanged within microbes and communication between the microbiota and the host have opened a new way of thinking about cancer biology. Probiotics are living organisms which administered in adequate amounts may bring health benefits and have the potential to be an integral part of the prevention/treatment strategies in clinical approaches. Here we provide a comprehensive review of data linking gut microbiota to cancer pathogenesis and its clinical course. We focus on gastrointestinal cancers, such as gastric, colorectal, pancreatic and liver cancer.

Clinicopathological and prognostic significance of Fusobacterium nucleatum infection in colorectal cancer: a meta-analysis

Background: This study aimed to clarify the relationship between F. nucleatum levels and the prognosis of CRC, which is still controversial.

Methods: Relevant articles were searched on PubMed, Web of Science, PMC and Embase up to April 7, 2020. Outcomes of interest included clinical characteristics, molecular characteristic and survival analysis. HR (OR), odds ratios (OR) and 95% confidence interval (CI) were calculated to explore the prognostic value and relationship of clinical characteristics of Fusobacterium nucleatum in CRC.

Results: A total of 3626 CRC patients from 13 eligible studies were included. High levels of F. nucleatum were associated with worse prognosis, as such parameters as overall survival (OS) (hazard ratio [HR] = 1.40, 95% confidence interval [CI]: 1.40 - 1.63, P < 0.0001), disease-free survival (DFS) (HR = 1.71, 95% CI: 1.29-2.26, P = 0.0002), and cancer-specific survival (OR= 1.93, 95% CI: 1.42-2.62, P <0.0001). F. nucleatum levels were related with T3-T4 stage (OR = 2.20, 95% CI: 1.66-2.91, P < 0.00001), M1 stage (OR = 2.11, 95% CI: 1.25-3.56, P = 0.005), poor tumor differentiation (OR = 1.83, 95% CI: 1.11-3.03, P =0.02), microsatellite instability-high (OR = 2.53, 95% CI: 1.53-4.20, P = 0.0003), and KRAS mutation (OR =1.27, 95% CI: 1.00-1.61, P=0.05) showed.

Conclusions: High levels of F. nucleatum suggest a poor prognosis and are associated with tumor growth, distant metastasis, poor differentiation, MSI-high, and KRAS mutation in CRC patients.

The Role of Fecal Fusobacterium nucleatum and pks+ Escherichia coli as Early Diagnostic Markers of Colorectal Cancer

BACKGROUND

Accurate analysis of intestinal microbiota will facilitate establishment of an evaluating system for assessing colorectal cancer (CRC) risk and prognosis. This study evaluates the potential role of Fusobacterium nucleatum (F. nucleatum) and Escherichia coli with a pks gene (pks⁺ E. coli) in early CRC diagnosis.

METHODS

We recruited 139 patients, including CRC (n = 60), colorectal adenomatous polyposis (CAP) (n = 37), and healthy individuals (n = 42) based on their colonoscopy examinations. We collected stool and serum samples from the participants and measured the relative abundance of F. nucleatum and pks⁺ E. coli in fecal samples by quantitative PCR. Receiver operating characteristic curve (ROC) analyses were used to analyze the diagnostic value of single or combined biomarkers.

RESULTS

Fecal F. nucleatum and pks⁺ E. coli levels were higher in the CRC group in either the CAP group or healthy controls (P = 0.02; 0.01). There was no statistical difference in the distribution of F. nucleatum and pks⁺ E. coli in patients with different tumor sites (P > 0.05). The combination of F. nucleatum+pks⁺ E. coli+CEA+CA19-9+FOBT was chosen as the optimal panel in differentiating both CRC and CAP from the controls. The combination of F. nucleatum, pks⁺ E. coli, and FOBT improved diagnostic efficiency. However, there was difficulty in differentiating CRC from CAP.

CONCLUSION

Our results suggested that combining bacterial markers with conventional tumor markers improves the diagnostic efficiency for noninvasive diagnosis of CRC.

The Role of Fusobacterium nucleatum in Colorectal Carcinogenesis

Colorectal cancer (CRC) is one of the most frequent and deadly neoplasms worldwide. Genetic factors, lifestyle habits, and inflammation are important risk factors associated with CRC development. In recent years, growing evidence has supporting the significant role of the intestinal microbiome in CRC carcinogenesis. Disturbances in the healthy microbial balance, known as dysbiosis, are frequently observed in these patients. Pathogenic microorganisms that induce intestinal dysbiosis have become an important target to determine the role of bacterial infection in tumorigenesis. Interestingly, the presence of different bacterial strains, such as Fusobacterium nucleatum, has been detected in tissue and stool from patients with CRC and associated with substantial clinical and molecular features, as well as with patient therapy response. Therefore, understanding how the presence and levels of F. nucleatumstrains in the gut affect the risk of CRC onset and progression may inform suitable candidates for interventions focused on modulation of this bacteria. Here we review new insights into the role of gut microbiota in CRC carcinogenesis and the clinical utility of using the detection of F. nucleatum in different settings such as screening, prognosis, and microbiota modulation as a means to prevent cancer, augment therapies, and reduce adverse effects of treatment.

Predictive values of colon microbiota in the treatment response to colorectal cancer

The crosstalk between the colon mucosa and the microbiota represents a complex and delicate equilibrium. Gastrointestinal diseases such as inflammatory bowel disease and colorectal cancer (CRC) are associated with a state of altered microbiota composition known as dysbiosis, which seems to play a causative role in some of these illnesses. Recent reports have shown that the colorectal microbiome is responsible for the response and safety to treatments against CRC, especially immunotherapy, hence opening the possibility to use bacteria as a predictive marker and also as a therapeutic agent. The review objective is to summarize updated reports about the the implication of the colorectal microbiome in the development of CRC, in treatment response and its potential as a therapeutic approach.

The influence of the gastrointestinal microbiome on colorectal metastasis: a narrative review

INTRODUCTION

The gastrointestinal microbiome has been suggested to contribute to the development of both primary and secondary colorectal cancer. Despite advances in understanding the prognostic and predictive value of clinico-pathological parameters, the underlying mechanisms that result in progression to metastatic disease have yet to be defined. The metastatic cascade involves a number of sequential steps, including detachment of tumour cells from the primary site, intravasation and dissemination within the circulatory and lymphatic systems, with extravasation and proliferation at a secondary site.

OBJECTIVE

An analysis of the literature relating to the gastrointestinal microbiome and its role in colorectal metastasis was conducted. This review aims to examine the current evidence supporting a role for the microbiome in colorectal metastasis and to describe the mechanisms by which it may contribute to metastatic progression.

CONCLUSION

The invasive pathways utilized by bacteria and how they may be manipulated by tumour cells for migration and metastasis are presented and the potential of the intestinal microbiome as a therapeutic target in colorectal carcinogenesis and metastasis is detailed here.