A Probiotic Formula for Modulation of Colorectal Cancer Risk via Reducing CRC-Associated Bacteria

Identifying fecal microbiota signatures of colorectal cancer in a Vietnamese cohort

Background

Colorectal cancer (CRC) is among the top three causes of global cancer mortality. In Vietnam, CRC is the third leading cause of death in women and the fourth cause of cancer mortality in men. A large number of metagenomic studies have reported the relationship between altered composition and function of the gut microbiota with CRC, but this relationship in low- and middle-income countries including Vietnam (with an estimated population of 100.3 million people in 2023, ranking 16th largest country by population in the world) is not well-explored.

Methods

We collected clinical data and fecal samples from 43 CRC patients and 44 healthy control subjects. The total community DNA of microorganisms was extracted from the fecal samples and analyzed for microbiota composition using Illumina MiSeq amplicon sequencing targeting the V3-V4 region of the 16S rRNA gene.

Results

We identified a significant difference in the overall fecal microbiota composition between CRC patients and healthy controls, and we detected several CRC-associated microbial signatures in fecal samples of Vietnamese patients with CRC, which overlapped with signatures from other countries and meta-analyses. Although patients with (n = 8) and without (n = 35) type 2 diabetes (T2D) exhibited distinct gut microbiota composition compared to healthy controls, increased relative abundances of putatively pathogenic species including Parvimonas micra, Peptostreptococcus stomatis, and Prevotella intermedia were consistent biomarkers for CRC. In contrast, several health-associated species were significantly depleted in CRC patients such as Lactobacillus johnsonii and Bifidobacterium longum in CRC/non-T2D patients, Ruminococcus species, Bacteroides uniformis, and Phascolarctobacterium faecium in CRC/T2D patients, and Butyricicoccus pullicaecorum in both CRC groups combined.

Conclusion

Our findings confirm alterations in gut microbiota composition in CRC in a pilot Vietnamese cohort and highlight several gut microbial taxa that may have inhibitory or driver roles in CRC. This and future studies will enable the development of cancer diagnostics and treatment strategies for CRC in Vietnam, with a focus on targeting the microbiota.

Screening and effects of intestinal probiotics on growth performance, gut health, immunity, and disease resistance of Nile tilapia (Oreochromis niloticus) against Streptococcus agalactiae

In the present study, 59 autochthonous bacteria were isolated from the intestine of tilapia. Following enzyme producing activity, antagonistic ability, hemolytic activity, drug sensitivity assessments, and in vivo safety evaluation, 7 potential probiotic strains were screened out: Bacillus tequilensis BT0825-2 (BT), Bacillus aryabhattai BA0829-3 (BA1), Bacillus megaterium BM0505-6 (BM), Bacillus velezensis BV0505-11 (BV), Bacillus licheniformis BL0505-18 (BL), B. aryabhattai BA0505-19 (BA2), and Lactococcus lactis LL0306-15 (LL). Subsequently, tilapia were fed basal diets (CT) and basal diets supplemented with 108 CFU/g of BT, BA1, BM, BV, BL, BA2 and LL, respectively. After 56 days of continuous feeding, the growth parameters (weight gain, final weight, and specific growth rate) showed significant improvement (p < 0.05) in both BM and BA2 groups. The total cholesterol and triglycerides of serum were significantly decreased in BV and LL groups (p < 0.05). The superoxide dismutase, glutathione reductase, and lysozyme of BV, BA2 and LL groups were increased, and the malondialdehyde of BV group was significantly decreased. The villous height and amylase of midgut were increased in BV, BA2 and LL groups. In addition, the expression levels of ZO-1 and occludin genes in the midgut of tilapia were enhanced in BM, BV, BA2 and LL groups. The supplementation of probiotics reduced the abundance of Cyanobacteria and increased the abundance of Actinobacteria at the phylum level. At the genus level, the addition of probiotics increased the abundance of Romboutsia. Furthermore, improvement in the expression of immune-related genes were observed, including interleukin 1β, interleukin 10, tumor necrosis factor alpha, and transforming growth factor beta (p < 0.05). After challenging with S. agalactiae, the survival rates of BV, BA2 and LL groups were significantly higher than CT group (p < 0.05). Above results indicated that BM, BA2, BV and LL improved growth performance, gut health or immunity of tilapia, which can be applied in tilapia aquaculture.

Exploring the gut microbiota and its potential as a biomarker in gliomas

Gut microbiome alterations are associated with various cancers including brain tumours such as glioma and glioblastoma. The gut communicates with the brain via a bidirectional pathway known as the gut-brain axis (GBA) which is essential for maintaining homeostasis. The gut microbiota produces many metabolites including short chain fatty acids (SCFAs) and essential amino acids such as glutamate, glutamine, arginine and tryptophan. Through the modulation of these metabolites the gut microbiome is able to regulate several functions of brain cells, immune cells and tumour cells including DNA methylation, mitochondrial function, the aryl hydrocarbon receptor (AhR), T-cell proliferation, autophagy and even apoptosis. Here, we summarise current findings on gut microbiome with respect to brain cancers, an area of research that is widely overlooked. Several studies investigated the relationship between gut microbiota and brain tumours. However, it remains unclear whether the gut microbiome variation is a cause or product of cancer. Subsequently, a biomarker panel was constructed for use as a predictive, prognostic and diagnostic tool with respect to multiple cancers including glioma and glioblastoma multiforme (GBM). This review further presents the intratumoural microbiome, a fascinating microenvironment within the tumour as a possible treatment target that can be manipulated to maximise effectiveness of treatment via personalised therapy. Studies utilising the microbiome as a biomarker and therapeutic strategy are necessary to accurately assess the effectiveness of the gut microbiome as a clinical tool with respect to brain cancers.

Microbiota Manipulation as an Emerging Concept in Cancer Therapy

Background

The human body is colonized by billions of bacteria that provide nutrients to the host, train our immune system, and importantly affect our heath. It has long been suggested that microbes might play a role in tumor pathogenesis; however, compelling evidence was only provided in the past decades when novel detection methods that do not depend on culturing techniques had been developed.

Summary

The microbiome impacts tumor development and anti-tumor therapies on various levels. Bacteria can promote or suppress tumor growth via direct interactions with cancer cells, production of metabolites that promote or inhibit tumor growth, and via stimulation or suppression of the local and systemic immune response. Cancer patients harbor a distinct microbiome when compared to healthy controls, which could potentially be employed to detect, identify, and treat cancer. Manipulation of the microbiome either via supplementation of single strains, bacterial consortia, fecal microbiota transfer or the use of pre- and probiotics has been suggested as therapeutic approach to directly target tumor growth or to enhance the efficacy of current state-of-the-art treatment options.

Key Messages

(1) Bacteria have a tremendous impact on anti-cancer immune responses. (2) Cancer patients harbor a distinct microbiome when compared to healthy controls. (3) The microbiome seems to be cancer-type specific. (4) Exploitation of bacteria to promote anti-tumor therapy is a novel, very promising venue in cancer treatment.

Probiotics intervention in colorectal cancer: From traditional approaches to novel strategies

ABSTRACT

The intestine harbors a large population of microorganisms that interact with epithelial cells to maintain host healthy physiological status. These intestinal microbiota engage in the fermentation of non-digestible nutrients and produce beneficial metabolites to regulate host homeostasis, metabolism, and immune response. The disruption of microbiota, known as dysbiosis, has been implicated in many intestinal diseases, including colorectal cancer (CRC). As the third most common cancer and the second leading cause of cancer-related death worldwide, CRC poses a significant health burden. There is an urgent need for novel interventions to reduce CRC incidence and improve clinical outcomes. Modulating the intestinal microbiota has emerged as a promising approach for CRC prevention and treatment. Current research efforts in CRC probiotics primarily focus on reducing the incidence of CRC, alleviating treatment-related side effects, and potentiating the efficacy of anticancer therapy, which is the key to successful translation to clinical practice. This paper aims to review the traditional probiotics and new interventions, such as next-generation probiotics and postbiotics, in the context of CRC. The underlying mechanisms of probiotic anti-cancer effects are also discussed, including the restoration of microbial composition, reinforcement of gut barrier integrity, induction of cancer cell apoptosis, inactivation of carcinogens, and modulation of host immune response. This paper further evaluates the novel strategy of probiotics as an adjuvant therapy in boosting the efficacy of chemotherapy and immunotherapy. Despite all the promising findings presented in studies, the evaluation of potential risks, optimization of delivery methods, and consideration of intra-patient variability of gut microbial baseline must be thoroughly interpreted before bench-to-bedside translation.