Probiotics and postbiotics in colorectal cancer: Prevention and complementary therapy

Unlocking the power of postbiotics: A revolutionary approach to nutrition for humans and animals

Postbiotics, which comprise inanimate microorganisms or their constituents, have recently gained significant attention for their potential health benefits. Extensive research on postbiotics has uncovered many beneficial effects on hosts, including antioxidant activity, immunomodulatory effects, gut microbiota modulation, and enhancement of epithelial barrier function. Although these features resemble those of probiotics, the stability and safety of postbiotics make them an appealing alternative. In this review, we provide a comprehensive summary of the latest research on postbiotics, emphasizing their positive impacts on both human and animal health. As our understanding of the influence of postbiotics on living organisms continues to grow, their application in clinical and nutritional settings, as well as animal husbandry, is expected to expand. Moreover, by substituting postbiotics for antibiotics, we can promote health and productivity while minimizing adverse effects. This alternative approach holds immense potential for improving health outcomes and revolutionizing the food and animal products industries.

The strain-dependent cytostatic activity of Lactococcus lactis on CRC cell lines is mediated through the release of arginine deiminase

BACKGROUND

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers, posing a serious public health challenge that necessitates the development of new therapeutics, therapies, and prevention methods. Among the various therapeutic approaches, interventions involving lactic acid bacteria (LAB) as probiotics and postbiotics have emerged as promising candidates for treating and preventing CRC. While human-isolated LAB strains are considered highly favorable, those sourced from environmental reservoirs such as dairy and fermented foods are also being recognized as potential sources for future therapeutics.

RESULTS

In this study, we present a novel and therapeutically promising strain, Lactococcus lactis ssp. lactis Lc4, isolated from dairy sources. Lc4 demonstrated the ability to release the cytostatic agent - arginine deiminase (ADI) - into the post-cultivation supernatant when cultured under conditions mimicking the human gut environment. Released arginine deiminase was able to significantly reduce the growth of HT-29 and HCT116 cells due to the depletion of arginine, which led to decreased levels of c-Myc, reduced phosphorylation of p70-S6 kinase, and cell cycle arrest. The ADI release and cytostatic properties were strain-dependent, as was evident from comparison to other L. lactis ssp. lactis strains.

CONCLUSION

For the first time, we unveil the anti-proliferative properties of the L. lactis cell-free supernatant (CFS), which are independent of bacteriocins or other small molecules. We demonstrate that ADI, derived from a dairy-Generally Recognized As Safe (GRAS) strain of L. lactis, exhibits anti-proliferative activity on cell lines with different levels of argininosuccinate synthetase 1 (ASS1) expression. A unique feature of the Lc4 strain is also its capability to release ADI into the extracellular space. Taken together, we showcase L. lactis ADI and the Lc4 strain as promising, potential therapeutic agents with broad applicability.

Lactobacillus plantarum Zhang-LL Inhibits Colitis-Related Tumorigenesis by Regulating Arachidonic Acid Metabolism and CD22-Mediated B-Cell Receptor Regulation

Colorectal cancer (CRC) is a significant health concern and is the third most commonly diagnosed and second deadliest cancer worldwide. CRC has been steadily increasing in developing countries owing to factors such as aging and epidemics. Despite extensive research, the exact pathogenesis of CRC remains unclear, and its causes are complex and variable. Numerous in vitro, animal, and clinical trials have demonstrated the efficacy of probiotics such as Lactobacillus plantarum in reversing the adverse outcomes of CRC. These findings suggest that probiotics play vital roles in the prevention, adjuvant treatment, and prognosis of CRC. In this study, we constructed a mouse model of CRC using an intraperitoneal injection of azomethane combined with dextran sodium sulfate, while administering 5-fluorouracil as well as high- and low-doses of L. plantarum Zhang-LL live or heat-killed strains. Weight changes and disease activity indices were recorded during feeding, and the number of polyps and colon length were measured after euthanasia. HE staining was used to observe the histopathological changes in the colons of mice, and ELISA was used to detect the expression levels of IL-1β, TNF-α, and IFN-γ in serum. To investigate the specific mechanisms involved in alleviating CRC progression, gut microbial alterations were investigated using 16S rRNA amplicon sequencing and non-targeted metabolomics, and changes in genes related to CRC were assessed using eukaryotic transcriptomics. The results showed that both viable and heat-killed strains of L. plantarum Zhang-LL in high doses significantly inhibited tumorigenesis, colon shortening, adverse inflammatory reactions, intestinal tissue damage, and pro-inflammatory factor expression upregulation. Specifically, in the gut microbiota, the abundance of the dominant flora Acutalibacter muris and Lactobacillus johnsonii was regulated, PGE2 expression was significantly reduced, the arachidonic acid metabolism pathway was inhibited, and CD22-mediated B-cell receptor regulation-related gene expression was upregulated. This study showed that L. plantarum Zhang-LL live or heat-inactivated strains alleviated CRC progression by reducing the abundance of potentially pathogenic bacteria, increasing the abundance of beneficial commensal bacteria, mediating the arachidonic acid metabolism pathway, and improving host immunogenicity.

[Gut Microbiome and Colorectal Cancer]

Colorectal cancer (CRC) is one of the most common cancers in Korea. A majority of CRCs are caused by progressive genomic alterations referred to as the adenoma-carcinoma sequence. The factors that may increase the risk of CRC include obesity and consumption of a high-fat diet, red meat, processed meat, and alcohol. Recently, the role of gut microbiota in the formation, progression and treatment of CRCs has been investigated in depth. An altered gut microbiota can drive carcinogenesis and cause the development of CRC. Studies have also shown the role of gut microbiota in the prevention of CRC and the impact of therapies involving gut microbiota on CRC. Herein, we summarize the current understanding of the role of the gut microbiota in the development of CRC and its therapeutic potential, including the prevention of CRC and in enhancing efficacy of chemotherapy and immunotherapy.

The protective role of Lactobacillus rhamnosus GG postbiotic on the alteration of autophagy and inflammation pathways induced by gliadin in intestinal models

Celiac disease (CD) is an autoimmune enteropathy caused by an abnormal immune response to gliadin peptides in genetically predisposed individuals. For people with CD, the only available therapy thus far is the lifelong necessity for a gluten-free diet (GFD). Innovative therapies include probiotics and postbiotics as dietary supplements, both of which may benefit the host. Therefore, the present study aimed to investigate the possible beneficial effects of the postbiotic Lactobacillus rhamnosus GG (LGG) in preventing the effects induced by indigested gliadin peptides on the intestinal epithelium. In this study, these effects on the mTOR pathway, autophagic function, and inflammation have been evaluated. Furthermore, in this study, we stimulated the Caco-2 cells with the undigested gliadin peptide (P31-43) and with the crude gliadin peptic-tryptic peptides (PTG) and pretreated the samples with LGG postbiotics (ATCC 53103) (1 × 108). In this study, the effects induced by gliadin before and after pretreatment have also been investigated. The phosphorylation levels of mTOR, p70S6K, and p4EBP-1 were increased after treatment with PTG and P31-43, indicating that the intestinal epithelial cells responded to the gliadin peptides by activating the mTOR pathway. Moreover, in this study, an increase in the phosphorylation of NF-κβ was observed. Pretreatment with LGG postbiotic prevented both the activation of the mTOR pathway and the NF-κβ phosphorylation. In addition, P31-43 reduced LC3II staining, and the postbiotic treatment was able to prevent this reduction. Subsequently, to evaluate the inflammation in a more complex intestinal model, the intestinal organoids derived from celiac disease patient biopsies (GCD-CD) and controls (CTR) were cultured. Stimulation with peptide 31-43 in the CD intestinal organoids induced NF-κβ activation, and pretreatment with LGG postbiotic could prevent it. These data showed that the LGG postbiotic can prevent the P31-43-mediated increase in inflammation in both Caco-2 cells and in intestinal organoids derived from CD patients.

Intestinal bacteria and colorectal cancer: etiology and treatment

The etiology of colorectal cancer (CRC) is influenced by bacterial communities that colonize the gastrointestinal tract. These microorganisms derive essential nutrients from indigestible dietary or host-derived compounds and activate molecular signaling pathways necessary for normal tissue and immune function. Associative and mechanistic studies have identified bacterial species whose presence may increase CRC risk, including notable examples such as Fusobacterium nucleatum, Enterotoxigenic Bacteroides fragilis, and pks⁺ E. coli. In recent years this work has expanded in scope to include aspects of host mutational status, intra-tumoral microbial heterogeneity, transient infection, and the cumulative influence of multiple carcinogenic bacteria after sequential or co-colonization. In this review, we will provide an updated overview of how host-bacteria interactions influence CRC development, how this knowledge may be utilized to diagnose or prevent CRC, and how the gut microbiome influences CRC treatment efficacy.

Effects of Long Non-Coding RNAs Induced by the Gut Microbiome on Regulating the Development of Colorectal Cancer

Although an imbalanced gut microbiome is closely associated with colorectal cancer (CRC), how the gut microbiome affects CRC is not known. Long non-coding RNAs (lncRNAs) can affect important cellular functions such as cell division, proliferation, and apoptosis. The abnormal expression of lncRNAs can promote CRC cell growth, proliferation, and metastasis, mediating the effects of the gut microbiome on CRC. Generally, the gut microbiome regulates the lncRNAs expression, which subsequently impacts the host transcriptome to change the expression of downstream target molecules, ultimately resulting in the development and progression of CRC. We focused on the important role of the microbiome in CRC and their effects on CRC-related lncRNAs. We also reviewed the impact of the two main pathogenic bacteria, Fusobacterium nucleatum and enterotoxigenic Bacteroides fragilis, and metabolites of the gut microbiome, butyrate, and lipopolysaccharide, on lncRNAs. Finally, available therapies that target the gut microbiome and lncRNAs to prevent and treat CRC were proposed.