Fusobacterium nucleatum and Colorectal Cancer

Therapeutic bacteria and viruses to combat cancer: double-edged sword in cancer therapy: new insights for future

Cancer, ranked as the second leading cause of mortality worldwide, leads to the death of approximately seven million people annually, establishing itself as one of the most significant health challenges globally. The discovery and identification of new anti-cancer drugs that kill or inactivate cancer cells without harming normal and healthy cells and reduce adverse effects on the immune system is a potential challenge in medicine and a fundamental goal in Many studies. Therapeutic bacteria and viruses have become a dual-faceted instrument in cancer therapy. They provide a promising avenue for cancer treatment, but at the same time, they also create significant obstacles and complications that contribute to cancer growth and development. This review article explores the role of bacteria and viruses in cancer treatment, examining their potential benefits and drawbacks. By amalgamating established knowledge and perspectives, this review offers an in-depth examination of the present research landscape within this domain and identifies avenues for future investigation.

Composition of the colon microbiota in the individuals with inflammatory bowel disease and colon cancer

The human intestine is a habitat for microorganisms and, recently, the composition of the intestinal microbiota has been correlated with the etiology of diseases such as inflammations, sores, and tumors. Although many studies have been conducted to understand the composition of that microbiota, expanding these studies to more samples and different backgrounds will improve our knowledge. In this work, we showed the colon microbiota composition and diversity of healthy subjects, patients with inflammatory bowel disease (IBD), and colon cancer by metagenomic sequencing. Our results indicated that the relative abundance of prokaryotic and eukaryotic microbes differs between the healthy vs. tumor biopsies, tumor vs. IBD biopsies, and fresh vs. paraffin-embedded tumor biopsies. Fusobacterium, Escherichia-Shigella, and Streptococcus genera were relatively abundant in fresh tumor biopsies, while Pseudomonas was significantly elevated in IBD biopsies. Additionally, another opportunist pathogen Malasseziales was revealed as the most abundant fungal clade in IBD biopsies, especially in ulcerative colitis. We also found that, while the Basidiomycota:Ascomycota ratio was slightly lower in tumor biopsies compared to biopsies from healthy subjects, there was a significant increase in IBD biopsies. Our work will contribute to the known diversity of prokaryotic and eukaryotic microbes in the colon biopsies in patients with IBD and colon cancer.

Porphyromonas gingivalis induced UCHL3 to promote colon cancer progression

Porphyromonas gingivalis (P. gingivalis), a Gram-negative oral anaerobe, was demonstrated to facilitate colonization and progression in colonic tumor, while the underlying mechanism still remains to be clarified. Here, we identified the proteome profile changed by P. gingivalis infection in HCT116 cells through label-free quantitative proteomics, and found that deubiquitinase UCHL3 was a key protein that response for P. gingivalis infection. By CCK8, colony formation, wound healing assays, and in vivo subcutaneous tumor mouse moudle, we proved that P. gingivalis could promote the proliferation and migration of colon cancer, while the process was inhibited by UCHL3 knock down. Through IP-MS, we identified GNG12 as the UCHL3 interacting protein. The protein level of GNG12 was significantly reduced when knock out UCHL3. Thus we propose that GNG12 is a substrate protein of UCHL3. Furthermore, we demonstrated that overexpression of GNG12 could restore the tumor inhibition effect caused by UCHL3 knock down, and UCHL3-GNG12 axis promote colon cancer progression via the NF-κB signal pathway. Collectively, this study unveiled that P. gingivalis infection up-regulated UCHL3 and stabilized its substrate protein GNG12 to activate the NF-κB signal pathway to promote colon cancer progression. Our study indicate that UCHL3 is a potential biomarker and therapeutic target for colon cancer which infected with P. gingivalis.

Gut microbiota profiles in feces and paired tumor and non-tumor tissues from Colorectal Cancer patients. Relationship to the Body Mass Index

Colorectal Cancer (CRC) and Obesity constitute two of the most common malignancies in the western world, and previously have been associated with intestinal microbial composition alterations. Our main aim in this study is to provide molecular data on intestinal microbiota patterns in subjects with CRC, as well as to establish possible associations with their Body Mass Index (BMI). A total of 113 samples from 45 subjects were collected and submitted to metagenomics analysis for gut microbiota. This study was performed by 16S ribosomal RNA bacterial gene amplification and sequencing using the Ion Torrent™ technology. The same dominant phyla were observed in feces and colorectal tissues, although a greater proportion of Fusobacteriota was found in tumor samples. Moreover, at the genus level, LEfSe analysis allowed us to detect a significant increase in Fusobacterium and Streptococcus in colorectal tissues with respect to fecal samples, with a significant preponderance of Fusobacterium in tumor tissues. Also, our data revealed relevant associations between gut microbiota composition and tumor location. When comparing bacterial profiles between right and left colon cancers, those from the left-sided colon showed a significant preponderance, among others, of the order Staphylococcales. Moreover, phyla Firmicutes and Spirochaetota were more abundant in the group of right-sided CRCs and phylum Proteobacteria was increased in rectal cancers. In relation to BMI of patients, we detected significant differences in beta diversity between the normal weight and the obese groups of cases. Microbiota from obese patients was significantly enriched, among others, in Bacteroidales. Therefore, our results are useful in the molecular characterization of CRC in obese and non-obese patients, with a clear impact on the establishment of diagnostic and prognosis of CRC.

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.

Detection of Fusobacterium nucleatum in Patients with Colitis-Associated Colorectal Cancer

Fusobacterium nucleatum is supposed to play a critical role in the development of colorectal cancer. The species has also been associated with ulcerative colitis (UC) that can progress into colorectal cancer, however, the involvement of bacteria in this process remains unclear. We analysed 177 colon biopsies obtained from patients during screening, including 20 healthy controls, 56 UC cases and 69 cases at different stages of progression to colitis-associated cancer (CAC); 32 samples of sporadic colorectal carcinoma (sCRC) were also included. The presence of F. nucleatum was detected by quantitative real-time PCR (qPCR). Our data show an association between the presence of the bacteria and the progression of carcinogenesis in UC patients. In 39.5% of CAC samples F. nucleatum was detected, compared to only 1.8% in UC cases. The bacteria were detected in 6.3% of samples with initial neoplastic transformation, so-called low-grade dysplasia (LGD), whereas high-grade dysplasia (HGD) resulted in 33.3% of samples positive for F. nucleatum. The fraction of F. nucleatum-positive samples from sCRC cases was 56.3%, which was not significantly different to the CAC group. We conclude that F. nucleatum is associated with the occurrence and progression of colon carcinogenesis, rather than with UC itself.

Pangenomic Study of Fusobacterium nucleatum Reveals the Distribution of Pathogenic Genes and Functional Clusters at the Subspecies and Strain Levels

Fusobacterium nucleatum is a prevalent periodontal pathogen and is associated with many systemic diseases. Our knowledge of the genomic characteristics and pathogenic effectors of different F. nucleatum strains is limited. In this study, we completed the whole genome assembly of the 4 F. nucleatum strains and carried out a comprehensive pangenomic study of 30 strains with their complete genome sequences. Phylogenetic analysis revealed that the F. nucleatum strains are mainly divided into 4 subspecies, while 1 of the sequenced strains was classified into a new subspecies. Gene composition analysis revealed that a total of 517 "core/soft-core genes" with housekeeping functions widely distributed in almost all the strains. Each subspecies had a unique gene cluster shared by strains within the subspecies. Analysis of the virulence factors revealed that many virulence factors were widely distributed across all the strains, with some present in multiple copies. Some virulence genes showed no consistent occurrence rule at the subspecies level and were specifically distributed in certain strains. The genomic islands mainly revealed strain-specific characteristics instead of subspecies level consistency, while CRISPR types and secondary metabolite biosynthetic gene clusters were identically distributed in F. nucleatum strains from the same subspecies. The variation in amino acid sites in the adhesion protein FadA did not affect the monomer and dimer 3D structures, but it may affect the binding surface and the stability of binding to host receptors. This study provides a basis for the pathogenic study of F. nucleatum at the subspecies and strain levels. IMPORTANCE We used F. nucleatum as an example to analyze the genomic characteristics of oral pathogens at the species, subspecies, and strain levels and elucidate the similarities and differences in functional genes and virulence factors among different subspecies/strains of the same oral pathogen. We believe that the unique biological characteristics of each subspecies/strain can be attributed to the differences in functional gene clusters or the presence/absence of certain virulence genes. This study showed that F. nucleatum strains from the same subspecies had similar functional gene compositions, CRISPR types, and secondary metabolite biosynthetic gene clusters, while pathogenic genes, such as virulence genes, antibiotic resistance genes, and GIs, had more strain level specificity. The findings of this study suggest that, for microbial pathogenicity studies, we should carefully consider the subspecies/strains being used, as different strains may vary greatly.

Tumorigenesis in Inflammatory Bowel Disease: Microbiota-Environment Interconnections

Colo-rectal cancer (CRC) is undoubtedly one of the most severe complications of inflammatory bowel diseases (IBD). While sporadic CRC develops from a typical adenoma-carcinoma sequence, IBD-related CRC follows different and less understood pathways and its pathophysiological mechanisms were not completely elucidated. In contrast to chronic inflammation, which is nowadays a well-recognised drive towards neoplastic transformation in IBD, only recently was gut microbiota demonstrated to interfere with both inflammation processes and immune-mediated anticancer surveillance. Moreover, the role of microbiota appears particularly complex and intriguing when also considering its multifaceted interactions with multiple environmental stimuli, notably chronic pathologies such as diabetes and obesity, lifestyle (diet, smoking) and vitamin intake. In this review, we presented a comprehensive overview on current evidence of the influence of gut microbiota on IBD-related CRC, in particular its mutual interconnections with the environment.

Association between colorectal cancer and expression levels of miR-21, miR-17-5P, miR-155 genes and the presence of Fusobacterium nucleatum in biopsy samples obtained from Iranian patients

BACKGROUND

Colorectal cancer (CRC) is considered the second-deadliest and third-most common malignancy worldwide. Studying the carcinogenic mechanism of bacteria or their role in aggravating cancer can be precious. Fusobacterium nucleatum (F. nucleatum) is one of the important bacteria in the occurrence and spread of CRC. In this study, we investigated the expression levels of miR-21, miR-17-5P, miR-155, and the relative frequency of F. nucleatum in biopsy samples from patients with CRC.

METHOD

DNA and RNA samples were extracted using a tissue extraction kit, and then cDNAs were synthesized using a related kit. Based on the sequence of miR-17-5P, miR-21, and miR-155 genes, F. nucleatum specific 16srRNA and bacterial universal16srRNA specific primers were selected, and the expression levels of the target genes were analyzed using the Real-Time PCR method.

RESULTS

The expression level of miR-21, miR-17-5P, and miR-155 genes showed a significant increase in the cancer group. Also, the expression of the mentioned miRNAs was significantly raised in the positive samples for F. nucleatum presence. The relative frequency of F. nucleatum in the cancer group was significantly increased compared to the control group.

CONCLUSION

Due to the changes in the expression of genes involved in causing CRC in the presence of F. nucleatum, it is possible to prompt identification and provide therapeutic solutions to cancer patients by studying their microbial profiles and the expression changes of different selected genes.

Effect of a bacteriocin-producing Streptococcus salivarius on the pathogen Fusobacterium nucleatum in a model of the human distal colon

The gut microbiome is a vast reservoir of microbes, some of which produce antimicrobial peptides called bacteriocins that may inhibit specific bacteria associated with disease. Fusobacterium nucleatum is an emerging human bacterial pathogen associated with gastrointestinal diseases including colorectal cancer (CRC). In this study, fecal samples of healthy donors were screened for potential bacteriocin-producing probiotics with antimicrobial activity against F. nucleatum. A novel isolate, designated as Streptococcus salivarius DPC6993 demonstrated a narrow-spectrum of antimicrobial activity against F. nucleatum in vitro. In silico analysis of the S. salivarius DPC6993 genome revealed the presence of genes involved in the production of the bacteriocins salivaricin A5 and salivaricin B. After 6 h in a colon fermentation model, there was a significant drop in the number of F. nucleatum in samples that had been simultaneously inoculated with S. salivarius DPC6993 + F. nucleatum DSM15643 compared to those inoculated with F. nucleatum DSM15643 alone (mean ± SD: 9243.3 ± 3408.4 vs 29688.9 ± 4993.9 copies/μl). Furthermore, 16S rRNA amplicon analysis revealed a significant difference in the mean relative abundances of Fusobacterium between samples inoculated with both S. salivarius DPC6993 and F. nucleatum DSM15643 (0.05%) and F. nucleatum DSM15643 only (0.32%). Diversity analysis indicated minimal impact exerted by S. salivarius DPC6993 on the surrounding microbiota. Overall, this study highlights the ability of a natural gut bacterium to target a bacterial pathogen associated with CRC. The specific targeting of CRC-associated pathogens by biotherapeutics may ultimately reduce the risk of CRC development and positively impact CRC outcomes.