Bifidobacterium animalis subspecies lactis engineered to produce mycosporin-like amino acids in colorectal cancer prevention

Mechanism of probiotics in the intervention of colorectal cancer: a review

The human microbiome interacts with the host mainly in the intestinal lumen, where putrefactive bacteria are suggested to promote colorectal cancer (CRC). In contrast, probiotics and their isolated components and secreted substances, display anti-tumor properties due to their ability to modulate gut microbiota composition, promote apoptosis, enhance immunity, resist oxidation and alter metabolism. Probiotics help to form a solid intestinal barrier against damaging agents via altering the gut microbiota and preventing harmful microbes from colonization. Probiotic strains that specifically target essential proteins involved in the process of apoptosis can overcome CRC resistance to apoptosis. They can increase the production of anti-inflammatory cytokines, essential in preventing carcinogenesis, and eliminate cancer cells by activating T cell-mediated immune responses. There is a clear indication that probiotics optimize the antioxidant system, decrease radical generation, and detect and degrade potential carcinogens. In this review, the pathogenic mechanisms of pathogens in CRC and the recent insights into the mechanism of probiotics in CRC prevention and therapy are discussed to provide a reference for the actual application of probiotics in CRC.

Reversal of Platinum-based Chemotherapy Resistance in Ovarian Cancer by Naringin Through Modulation of The Gut Microbiota in a Humanized Nude Mouse Model

As a chemotherapy agent, cisplatin (DDP) is often associated with drug resistance and gastrointestinal toxicity, factors that severely limit therapeutic efficacy in patients with ovarian cancer (OC). Naringin has been shown to increase sensitivity to cisplatin, but whether the intestinal microbiota is associated with this effect has not been reported so far. In this study, we applied a humanized mouse model for the first time to evaluate the reversal of cisplatin resistance by naringin, as well as naringin combined with the microbiota in ovarian cancer. The results showed that naringin combined with Bifidobacterium animalis subsp. lactis NCU-01 had an inhibitory effect on the tumor, significantly reducing tumor size (p<0.05), as well as the concentrations of serum tumor markers CA125 and HE4, increased the relative abundance of Bifidobacterium and Bacteroides, inhibit Toll-like receptor 4 (TLR4)/nuclear factor κB (NF-κB)-induced intestinal inflammation and increase the expression of intestinal permeability-associated proteins ZO-1 (p<0.001) and occludin (p<0.01). In conclusion, the above data demonstrate how naringin combined with Bifidobacterium animalis subsp. lactis NCU-01 reverses cisplatin resistance in ovarian cancer by modulating the intestinal microbiota, inhibiting the TLR4/NF-κB signaling pathway and modulating the p38MAPK signaling pathway.

Applications of mycosporine-like amino acids beyond photoprotection

Recent years have seen a lot of interest in mycosporine-like amino acids (MAAs) because of their alleged potential as a natural microbial sunscreen. Since chemical ultraviolet (UV) absorbers are unsafe for long-term usage, the demand for natural UV-absorbing substances has increased. In this situation, MAA is a strong contender for an eco-friendly UV protector. The capacity of MAAs to absorb light in the UV-A (320-400 nm) and UV-B (280-320 nm) range without generating free radicals is potentially relevant in photoprotection. The usage of MAAs for purposes other than photoprotection has now shifted in favor of medicinal applications. Aside from UV absorption, MAAs also have anti-oxidant, anti-inflammatory, wound-healing, anti-photoaging, cell proliferation stimulators, anti-cancer agents, and anti-adipogenic properties. Recently, MAAs application to combat SARS-CoV-2 infection was also investigated. In this review article, we highlight the biomedical applications of MAAs that go beyond photoprotection, which can help in utilizing the MAAs as promising bioactive compounds in both pharmaceutical and cosmetic applications.

Intratumoural microbiota: from theory to clinical application

Cancer is a major cause of high morbidity and mortality worldwide. Several environmental, genetic and lifestyle factors are associated with the development of cancer in humans and result in suboptimal treatment. The human microbiota has been implicated in the pathophysiological process of cancer and has been used as a diagnostic, prognostic and risk assessment tool in cancer management. Notably, both extratumoural and intratumoural microbiota are important components of the tumor microenvironment, subtly influencing tumorigenesis, progression, treatment and prognosis. The potential oncogenic mechanisms of action of the intratumoural microbiota include induction of DNA damage, influence on cell signaling pathways and impairment of immune responses. Some naturally occurring or genetically engineered microorganisms can specifically accumulate and replicate in tumors and then initiate various anti-tumor programs, ultimately promoting the therapeutic effect of tumor microbiota and reducing the toxic and side effects of conventional tumor treatments, which may be conducive to the pursuit of accurate cancer treatment. In this review, we summarise evidence revealing the impact of the intratumoural microbiota on cancer occurrence and progress and potential therapeutic and diagnostic applications, which may be a promising novel strategy to inhibit tumor development and enhance therapeutic efficacy. Video Abstract.

Microbiota regulation in constipation and colorectal cancer

The relevance of constipation to the development and progression of colorectal cancer (CRC) is currently a controversial issue. Studies have shown that changes in the composition of the gut microbiota, a condition known as ecological imbalance, are correlated with an increasing number of common human diseases, including CRC and constipation. CRC is the second leading cause of cancer-related deaths worldwide, and constipation has been receiving widespread attention as a risk factor for CRC. Early colonoscopy screening of constipated patients, with regular follow-ups and timely intervention, can help detect early intestinal lesions and reduce the risks of developing colorectal polyps and CRC. As an important regulator of the intestinal microenvironment, the gut microbiota plays a critical role in the onset and progression of CRC. An increasing amount of evidence supports the thought that gut microbial composition and function are key determinants of CRC development and progression, with alterations inducing changes in the expression of host genes, metabolic regulation, and local and systemic immunological responses. Furthermore, constipation greatly affects the composition of the gut microbiota, which in turn influences the susceptibility to intestinal diseases such as CRC. However, the crosstalk between the gut microbiota, constipation, and CRC is still unclear.

Probiotic powder ameliorates colorectal cancer by regulating Bifidobacterium animalis, Clostridium cocleatum, and immune cell composition

Based on the relationship between the gut microbiota and colorectal cancer, we developed a new probiotic powder for treatment of colorectal cancer. Initially, we evaluated the effect of the probiotic powder on CRC using hematoxylin and eosin staining, and evaluated mouse survival rate and tumor size. We then investigated the effects of the probiotic powder on the gut microbiota, immune cells, and apoptotic proteins using 16S rDNA sequencing, flow cytometry, and western blot, respectively. The results showed that the probiotic powder improved the intestinal barrier integrity, survival rate, and reduced tumor size in CRC mice. This effect was associated with changes in the gut microbiota. Specifically, the probiotic powder increased the abundance of Bifidobacterium animalis and reduced the abundance of Clostridium cocleatum. In addition, the probiotic powder resulted in decreased numbers of CD4+ Foxp3+ Treg cells, increased numbers of IFN-γ+ CD8+ T cells and CD4+ IL-4+ Th2 cells, decreased expression of the TIGIT in CD4+ IL-4+ Th2 cells, and increased numbers of CD19+ GL-7+ B cells. Furthermore, the expression of the pro-apoptotic protein BAX was significantly increased in tumor tissues in response to the probiotic powder. In summary, the probiotic powder ameliorated CRC by regulating the gut microbiota, reducing Treg cell abundance, promoting the number of IFN-γ+ CD8+ T cells, increasing Th2 cell abundance, inhibiting the expression of TIGIT in Th2 cells, and increasing B cell abundance in the immune microenvironment of CRC, thereby increasing the expression of BAX in CRC.

The role of gut microbiota in the development of colorectal cancer: a review

PURPOSE

Colorectal cancer (CRC) is the cancer of the colon and rectum. Recent research has found a link between CRC and human gut microbiota. This review explores the effect of gut microbiota on colorectal carcinogenesis and the development of chemoresistance.

METHODS

A literature overview was performed to identify the gut microbiota species that showed altered abundance in CRC patients and the mechanisms by which some of them aid in the development of chemoresistance.

RESULTS

Types of gut microbiota present and methods of analyzing them were discussed. We observed that numerous microbiota showed altered abundance in CRC patients and could act as a biomarker for CRC diagnosis and treatment. Further, it was demonstrated that microbes also have a role in the development of chemoresistance by mechanisms like immune system activation, drug modification, and autophagy modulation. Finally, the key issue of the growing global problem of antimicrobial resistance and its relationship with CRC was highlighted.

CONCLUSION

This review discussed the role of gut microbiota dysbiosis on colorectal cancer progression and the development of chemoresistance.

Diagnostic, Prognostic, and Therapeutic Roles of Gut Microbiota in COVID-19: A Comprehensive Systematic Review

Introduction

The Coronavirus Disease 2019 (COVID-19) pandemic caused by Severe Acute Respiratory Coronavirus 2 (SARS-CoV-2) emerged in late December 2019. Considering the important role of gut microbiota in maturation, regulation, and induction of the immune system and subsequent inflammatory processes, it seems that evaluating the composition of gut microbiota in COVID-19 patients compared with healthy individuals may have potential value as a diagnostic and/or prognostic biomarker for the disease. Also, therapeutic interventions affecting gut microbial flora may open new horizons in the treatment of COVID-19 patients and accelerating their recovery.

Methods

A systematic search was conducted for relevant studies published from December 2019 to December 2021 using Pubmed/Medline, Embase, and Scopus. Articles containing the following keywords in titles or abstracts were selected: "SARS-CoV-2" or "COVID-19" or "Coronavirus Disease 19" and "gastrointestinal microbes" or "dysbiosis" or "gut microbiota" or "gut bacteria" or "gut microbes" or "gastrointestinal microbiota".

Results

Out of 1,668 studies, 22 articles fulfilled the inclusion criteria and a total of 1,255 confirmed COVID-19 patients were examined. All included studies showed a significant association between COVID-19 and gut microbiota dysbiosis. The most alteration in bacterial composition of COVID-19 patients was depletion in genera Ruminococcus, Alistipes, Eubacterium, Bifidobacterium, Faecalibacterium, Roseburia, Fusicathenibacter, and Blautia and enrichment of Eggerthella, Bacteroides, Actinomyces, Clostridium, Streptococcus, Rothia, and Collinsella. Also, some gut microbiome alterations were associated with COVID-19 severity and poor prognosis including the increment of Bacteroides, Parabacteroides, Clostridium, Bifidobacterium, Ruminococcus, Campylobacter, Rothia, Corynebacterium, Megasphaera, Enterococcus, and Aspergillus spp. and the decrement of Roseburia, Eubacterium, Lachnospira, Faecalibacterium, and the Firmicutes/Bacteroidetes ratio.

Conclusion

Our study showed a significant change of gut microbiome composition in COVID-19 patients compared with healthy individuals. This great extent of impact has proposed the gut microbiota as a potential diagnostic, prognostic, and therapeutic strategy for COVID-19. There is much evidence about this issue, and it is expected to be increased in near future.

Supplementation of kefir ameliorates azoxymethane/dextran sulfate sodium induced colorectal cancer by modulating the gut microbiota

The aim of this study was to investigate the efficacy of kefir on colorectal cancer (CRC) via regulating the microbiota structure in the colon using the azoxymethane/dextran sulfate sodium (AOM/DSS) induced CRC mouse model. Mice in the treatment group were orally administered with milk or kefir. The gut microbiota composition was assessed by internally transcribed spacer 2 (ITS2) and 16S rRNA high-throughput sequencing. Furthermore, the biomarkers associated with the gut barrier, inflammation, and cell proliferation regulators were evaluated. The results indicated that the size and the amount of tumor were decreased and the immunity regulators (TNF-α, IL-6, and IL-17a) and oncocyte proliferation indicator (Ki67, NF-κB, and β-catenin) were all decreased. Increased short chain fatty acids (SCFAs) lowered the pH in the colon and helped enhance the intestinal barrier. The Firmicutes/Bacteroidetes ratio and Ascomycota/Basidiomycota ratio were decreased at the phylum level; the relative abundance of probiotics was increased and the pathogenic bacterium (Clostridium sensu stricto, Aspergillus and Talaromyces) were decreased after supplementation of kefir. Consequently, kefir could regulate the gut microbiota composition and ameliorate AOM/DSS induced colorectal cancer.

Exploring the Role of Gut Microbiome in Colon Cancer

Dysbiosis of the gut microbiome has been associated with the development of colorectal cancer (CRC). Gut microbiota is involved in the metabolic transformations of dietary components into oncometabolites and tumor-suppressive metabolites that in turn affect CRC development. In a healthy colon, the major of microbial metabolism is saccharolytic fermentation pathways. The alpha-bug hypothesis suggested that oncogenic bacteria such as enterotoxigenic Bacteroides fragilis (ETBF) induce the development of CRC through direct interactions with colonic epithelial cells and alterations of microbiota composition at the colorectal site. Escherichia coli, E. faecalis, F. nucleatum, and Streptococcus gallolyticus showed higher abundance whereas Bifidobacterium, Clostridium, Faecalibacterium, and Roseburia showed reduced abundance in CRC patients. The alterations of gut microbiota may be used as potential therapeutic approaches to prevent or treat CRC. Probiotics such as Lactobacillus and Bifidobacterium inhibit the growth of CRC through inhibiting inflammation and angiogenesis and enhancing the function of the intestinal barrier through the secretion of short-chain fatty acids (SCFAs). Crosstalk between lifestyle, host genetics, and gut microbiota is well documented in the prevention and treatment of CRC. Future studies are required to understand the interaction between gut microbiota and host to the influence and prevention of CRC. However, a better understanding of bacterial dysbiosis in the heterogeneity of CRC tumors should also be considered. Metatranscriptomic and metaproteomic studies are considered a powerful omic tool to understand the anti-cancer properties of certain bacterial strains. The clinical benefits of probiotics in the CRC context remain to be determined. Metagenomic approaches along with metabolomics and immunology will open a new avenue for the treatment of CRC shortly. Dietary interventions may be suitable to modulate the growth of beneficial microbiota in the gut.

The Role of the Gut Microbiome in Colorectal Cancer Development and Therapy Response

Colorectal cancer (CRC) is the third most common cancer worldwide and the leading cause of cancer-related deaths. Recently, several studies have demonstrated that gut microbiota can alter CRC susceptibility and progression by modulating mechanisms such as inflammation and DNA damage, and by producing metabolites involved in tumor progression or suppression. Dysbiosis of gut microbiota has been observed in patients with CRC, with a decrease in commensal bacterial species (butyrate-producing bacteria) and an enrichment of detrimental bacterial populations (pro-inflammatory opportunistic pathogens). CRC is characterized by altered production of bacterial metabolites directly involved in cancer metabolism including short-chain fatty acids and polyamines. Emerging evidence suggests that diet has an important impact on the risk of CRC development. The intake of high-fiber diets and the supplementation of diet with polyunsaturated fatty acids, polyphenols and probiotics, which are known to regulate gut microbiota, could be not only a potential mechanism for the reduction of CRC risk in a primary prevention setting, but may also be important to enhance the response to cancer therapy when used as adjuvant to conventional treatment for CRC. Therefore, a personalized modulation of the pattern of gut microbiome by diet may be a promising approach to prevent the development and progression of CRC and to improve the efficacy of antitumoral therapy.

The probiotic Bifidobacterium in the management of Coronavirus: A theoretical basis

COVID-19 is a viral pandemic that primarily manifests with respiratory distress but may also lead to symptoms and signs associated with the gastrointestinal tract. It is characteristically associated with a hyper-immune response, also referred to as a 'cytokine storm'. Probiotics are living microorganisms that have been shown to have positive effects on immune response in man with some bacteria; some strains of Bifidobacteria, for example, possess especially potent immune modulating effects. These bacteria have the potential to ameliorate the 'cytokine storm' through a differential effect on pro- and anti-inflammatory cytokines. In the management of COVID-19 and other coronovirus-mediated illnesses, probiotic bacteria also have the potential to enhance vaccine efficacy.

Smoking and microbiome in oral, airway, gut and some systemic diseases

The human microbiome harbors a diverse array of microbes which establishes a mutually beneficial relation with the host in healthy conditions, however, the dynamic homeostasis is influenced by both host and environmental factors. Smoking contributes to modifications of the oral, lung and gut microbiome, leading to various diseases, such as periodontitis, asthma, chronic obstructive pulmonary disease, Crohn’s disease, ulcerative colitis and cancers. However, the exact causal relationship between smoking and microbiome alteration remains to be further explored.

Bifidobacteria and Mucosal-Associated Invariant T (MAIT) Cells: A New Approach to Colorectal Cancer Prevention?

Colorectal cancer is the most preventable form of cancer worldwide. The pathogenesis of colorectal cancer includes gut inflammation, genetic and microbial composition factors. İmpairment of the gut microbiota has been associated with development of colorectal cancer. The genus Bifidobacterium is an important component of the commensal gut microbiota. Bifidobacteria are considered to have important roles in multiple homeostatic functions: immunologic, hormonal and metabolic. Mucosal-associated invariant T cells (MAIT) are components of the immune system involved in protection against infectious pathogens and regulate the pathogenesis of various inflammatory diseases and, potentially, colorectal cancer. Engagement between Bifidobacterium and MAIT cells could exert a beneficial effect on colorectal cancer prevention and treatment.

Microbiome and colorectal cancer: Roles in carcinogenesis and clinical potential

The gastrointestinal tract harbors most of the microbiota associated with humans. In recent years, there has been a surge of interest in assessing the relationships between the gut microbiota and several gut alterations, including colorectal cancer. Changes in the gut microbiota in patients suffering colorectal cancer suggest a possible role of host-microbe interactions in the origin and development of this malignancy and, at the same time, open the door for novel ways of preventing, diagnosing, or treating this disease. In this review we survey current knowledge on the healthy microbiome of the gut and how it is altered in colorectal cancer and other related disease conditions. In describing past studies we will critically assess technical limitations of different approaches and point to existing challenges in microbiome research. We will have a special focus on host-microbiome interaction mechanisms that may be important to explain how dysbiosis can lead to chronic inflammation and drive processes that influence carcinogenesis and tumor progression in colon cancer. Finally, we will discuss the potential of recent developments of novel microbiota-based therapeutics and diagnostic tools for colorectal cancer.