Clinical significance of Bacteroides fragilis as a potential prognostic factor in colorectal cancer

Prevalence of enterotoxigenic Bacteroides fragilis in patients with colorectal cancer: a systematic review and meta-analysis

Introduction

The gut microbiome, specifically enterotoxigenic Bacteroides fragilis (ETBF), has been reported to play a role in colorectal cancer development. We aimed to conduct a systematic review and meta-analysis of published studies to compare the prevalence of ETBF in patients with colorectal cancer and healthy controls as well as in various stages of colorectal cancer.

Methods

PubMed, EMBASE, and The Cochrane Library were systematically searched for studies published until May 2024. We utilized studies either comparing the prevalence of ETBF in patients with colorectal cancer and healthy control or examining its prevalence across different stages of colorectal cancer. The prevalence of ETBF colonization in biological samples from individuals with colorectal cancer compared to that in healthy controls or adjacent normal tissue as well as the association between the prevalence of ETBF and various stages of colorectal cancer were plotted using a random-effect or fixed-effect model.

Results

Fourteen relevant articles were identified. Meta-analyses revealed that patients with colorectal cancer had a higher likelihood of having ETBF than healthy controls (odds ratio [OR]: 2.54, 95% confidence interval [CI]: 1.63-3.98, I2 = 55%). Additionally, ETBF detection was lower in stage I/II than in stage III/IV colorectal cancer (OR: 0.61, 95% CI: 0.41-0.91, I2 = 41%).

Discussion

The prevalence of ETBF was consistently higher in the tissue and fecal samples of patients with colorectal cancer than in those of controls. A difference in ETBF prevalence between stage I/II and stage III/IV colorectal cancer was noted, but further analysis revealed that the conclusion is unreliable.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD 42024548325.

TphPMF: A microbiome data imputation method using hierarchical Bayesian Probabilistic Matrix Factorization

In microbiome research, data sparsity represents a prevalent and formidable challenge. Sparse data not only compromises the accuracy of statistical analyses but also conceals critical biological relationships, thereby undermining the reliability of the conclusions. To tackle this issue, we introduce a machine learning approach for microbiome data imputation, termed TphPMF. This technique leverages Probabilistic Matrix Factorization, incorporating phylogenetic relationships among microorganisms to establish Bayesian prior distributions. These priors facilitate posterior predictions of potential non-biological zeros. We demonstrate that TphPMF outperforms existing microbiome data imputation methods in accurately recovering missing taxon abundances. Furthermore, TphPMF enhances the efficacy of certain differential abundance analysis methods in detecting differentially abundant (DA) taxa, particularly showing advantages when used in conjunction with DESeq2-phyloseq. Additionally, TphPMF significantly improves the precision of cross-predicting disease conditions in microbiome datasets pertaining to type 2 diabetes and colorectal cancer.

Microbiome Differences in Colorectal Cancer Patients and Healthy Individuals: Implications for Vaccine Antigen Discovery

Background

Colorectal cancer (CRC) is the third most prevalent cancer worldwide, with numerous risk factors contributing to its development. Recent research has illuminated the significant role of the gut microbiota in CRC pathogenesis, identifying various microbial antigens as potential targets for vaccine development.

Aim

This review aimed at exploring the potential sources of microbial antigens that could be harnessed to create effective CRC vaccines and understand the role of microbiome-CRC interactions in carcinogenesis.

Methods

A comprehensive search of original research and review articles on the pathological links between key microbial candidates, particularly those more prevalent in CRC tissues, was conducted. This involved extensive use of the PubMed and Medline databases, as well as the Google Scholar search engine, utilizing pertinent keywords. A total of one hundred and forty-three relevant articles in English, mostly published between 2018 and 2024, were selected.

Results

Numerous microbes, particularly bacteria and viruses, are significantly overrepresented in CRC tissues and have been shown to promote tumorigenesis by inducing inflammation and modulating the immune system. This makes them promising candidates for antigens in the development of CRC vaccines.

Conclusion

The selection of microbial antigens focuses on their capacity to trigger a strong immune response and their link to tumor presence and progression. Identifying and validating these antigens through preclinical testing is essential in developing a CRC vaccine.

Association of Fusobacterium nucleatum infection with colorectal cancer in Kazakhstani patients

Objectives

Fusobacterium nucleatum is a gram-negative anaerobic bacillus associated with colorectal cancer (CRC). We aimed to determine the abundance of F. nucleatum and other CRC-associated bacteria using quantitative real-time polymerase chain reaction (qPCR) analysis to detect the possible correlations between tumor and normal tissues and the relationships between patients' clinical characteristics, diet, and CRC-associated bacteria.

Methods

A total of 249 biopsy samples of tumor and paired normal tissues were collected from patients with CRC. Biopsy samples were screened for detection of F. nucleatum using qPCR targeting nusG gene. Bacteroides fragilis, Escherichia coli, and Streptococcus gallolyticus were also detected in the samples using species-specific genes.

Results

The frequencies of detection of F. nucleatum in the tumor and normal tissues of patients with CRC were 43.37 and 24.1%, respectively (P < 0.05). Statistical analysis using cycle threshold (Ct) values from qPCR data and clinical characteristics showed that tumor size, tumor location, and processed meat consumption were significantly correlated with the abundance of F. nucleatum (P < 0.05). The significance of the prevalence of B. fragilis and E. coli in tumor tissues was marginally higher than that in normal tissues (P < 0.1), and the consumption of processed/red meat affected the prevalence of these bacteria (P < 0.05).

Conclusions

Our results showed an association between the presence of F. nucleatum in tumor tissues and CRC, indicating that F. nucleatum may be a potential marker for CRC diagnosis. F. nucleatum is enriched in CRC tissues and is associated with CRC development.

Gut microbiota characteristics of colorectal cancer patients in Hubei, China, and differences with cohorts from other Chinese regions

The research on the correlation or causality between gut microbiota and the occurrence, development, and treatment of colorectal cancer (CRC) is receiving increasing emphasis. At the same time, the incidence and mortality of colorectal cancer vary among individuals and regions, as does the gut microbiota. In order to gain a better understanding of the characteristics of the gut microbiota in CRC patients and the differences between different regions, we initially compared the gut microbiota of 25 CRC patients and 26 healthy controls in the central region of China (Hubei Province) using 16S rRNA high-throughput sequencing technology. The results showed that Corynebacterium, Enterococcus, Lactobacillus, and Escherichia-Shigella were significantly enriched in CRC patients. In addition, we also compared the potential differences in functional pathways between the CRC group and the healthy control group using PICRUSt's functional prediction analysis. We then analyzed and compared it with five cohort studies from various regions of China, including Central, East, and Northeast China. We found that geographical factors may affect the composition of intestinal microbiota in CRC patients. The composition of intestinal microbiota is crucial information that influences colorectal cancer screening, early detection, and the prediction of CRC treatment outcomes. This emphasizes the importance of conducting research on CRC-related gut microbiota in various regions of China.

pH-Sensitive Nanoparticles of Epigallocatechin-3-Gallate in Enhanced Colorectal Cancer Therapy

AIM

Encapsulating epigallocatechin-3-gallate (EGCG) in pH-sensitive polymeric nanoparticles for targeted delivery of drugs could revolutionize colorectal cancer treatment.

MATERIALS & METHODS

Nanoparticles were synthesized to release drugs at colon pH. Dynamic light scattering measured their average diameter and ζ-potential, while differential scanning calorimetry and x-ray diffraction assessed EGCG encapsulation.

RESULTS

The nanoparticles showed stability and bioavailability in the gastrointestinal tract, efficiently encapsulating and releasing over 93% of EGCG at pH 7.2. They enhanced cytotoxicity against HT-29 cells and demonstrated antibacterial properties, increasing apoptosis and cell cycle arrest.

CONCLUSION

The study underscores the potential of nanoparticles in enhancing EGCG delivery for colorectal cancer therapy, aiming to minimize side effects and improve therapeutic outcomes.