Postbiotics, Metabolic Signaling, and Cancer

Initiation of Apoptotic Pathway by the Cell-Free Supernatant Synthesized from Weissella cibaria Through In-Silico and In-Vitro Methods

Globally, colorectal cancer is the most prevalent type of cancer. Even though multiple treatments such as surgery, radiation, chemotherapy, and immunotherapy are available, the adverse effects caused in patients seem remarkable. Therefore, the current work was deliberated to prepare the metabolites (cell-free supernatant-CFS) from Weissella cibaria RK-3-1 to conduct in-silico and in-vitro-based anticancer assays. First, the active biomolecules present in the CFS were screened using a GC-MS analyzer. In addition, in-silico-based pharmacokinetic and docking studies were performed to confirm the anticancer potential of metabolites. In-silico results suggested that the bioactive compounds such as filicinic acid, dibutyl phthalate, and 4H-pyran-4-one,2,3-dihydro-3,5-dihydroxy-6-methyl present in CFS possessed significant molecular docking interactions with anticancer hub proteins. Furthermore, in-vitro results displayed the inhibition of cell proliferation in HT-29 cells at an IC50 value of 22.5 ± 1.3 µg/ml with the least significant effect on HEK-293 cell lines. Moreover, bacterial metabolites-controlled cell proliferation during the cell cycle's synthesis phase (S). Furthermore, the gene expression results confirm the increased expression of Bad, Bax, Bcl2, caspase-3, and cytochrome-C genes involved in the intrinsic apoptotic pathway. Hence, our findings from the in-silico and the in-vitro study confirm the anticancer potential of cell free-supernatant synthesized by W. cibaria.

Modulation of Gut Microbial Biomarkers and Metabolites in Cancer Management by Tea Compounds

Cancers are causing millions of deaths and leaving a huge clinical and economic burden. High costs of cancer drugs are limiting their access to the growing number of cancer cases. The development of more affordable alternative therapy could reach more patients. As gut microbiota plays a significant role in the development and treatment of cancer, microbiome-targeted therapy has gained more attention in recent years. Dietary and natural compounds can modulate gut microbiota composition while providing broader and more accessible access to medicine. Tea compounds have been shown to have anti-cancer properties as well as modulate the gut microbiota and their related metabolites. However, there is no comprehensive review that focuses on the gut modulatory effects of tea compounds and their impact on reshaping the metabolic profiles, particularly in cancer models. In this review, the effects of different tea compounds on gut microbiota in cancer settings are discussed. Furthermore, the relationship between these modulated bacteria and their related metabolites, along with the mechanisms of how these changes led to cancer intervention are summarized.

Benefits and concerns of probiotics: an overview of the potential genotoxicity of the colibactin-producing Escherichia coli Nissle 1917 strain

Recently, the mounting integration of probiotics into human health strategies has gathered considerable attention. Although the benefits of probiotics have been widely recognized in patients with gastrointestinal disorders, immune system modulation, and chronic-degenerative diseases, there is a growing need to evaluate their potential risks. In this context, new concerns have arisen regarding the safety of probiotics as some strains may have adverse effects in humans. Among these strains, Escherichia coli Nissle 1917 (EcN) exhibited traits of concern due to a pathogenic locus in its genome that produces potentially genotoxic metabolites. As the use of probiotics for therapeutic purposes is increasing, the effects of potentially harmful probiotics must be carefully evaluated. To this end, in this narrative review article, we reported the findings of the most relevant in vitro and in vivo studies investigating the expanding applications of probiotics and their impact on human well-being addressing concerns arising from the presence of antibiotic resistance and pathogenic elements, with a focus on the polyketide synthase (pks) pathogenic island of EcN. In this context, the literature data here discussed encourages a thorough profiling of probiotics to identify potential harmful elements as done for EcN where potential genotoxic effects of colibactin, a secondary metabolite, were observed. Specifically, while some studies suggest EcN is safe for gastrointestinal health, conflicting findings highlight the need for further research to clarify its safety and optimize its use in therapy. Overall, the data here presented suggest that a comprehensive assessment of the evolving landscape of probiotics is essential to make evidence-based decisions and ensure their correct use in humans.

Quantification of Bioactive Metabolites Derived from Cell-Free Supernatant of Pediococcus acidilactici and Screening their Protective Properties in Frankfurters

The specific aims of the current study were to determine and quantify the bioactive compounds derived from the cell-free supernatant (CFS) of Pediococcus acidilactici and screen their protective effect in frankfurters by applying an edible coating. This was achieved by immersing the peeled frankfurters in the CFS (CFS: 50% and 100%) alone or in combination with chitosan (CH: 0.5% and 1%) solutions for 3 min. Untreated frankfurter samples (control) exceeded the maximum acceptable total viable count limit (7.0 log10) on the 14th day, whereas samples treated with 100% CFS + 1% chitosan reached the limit on day 28 during refrigerated storage (P < 0.05). This treatment provided a 14-day extension to the shelf life of frankfurters without causing any significant changes in color and sensory attributes (P > 0.05). Additionally, this treatment inhibited oxidation in the frankfurters, leading to no significant changes in TBA and TVB-N within this group during storage (P > 0.05). This protective effect was mainly attributed to the wide variety of bioactive compounds identified in the CFS, including a total of 5 organic acids, 20 free amino acids, 11 free fatty acids, 77 volatiles, and 10 polyphenols. Due to these bioactive compounds, CFS exhibited a strong radical scavenging capacity (DPPH: 435.08 TEAC/L, ABTS: 75.01 ± 0.14 mg TEAC/L; FRAP: 1.30 ± 0.03 mM FE/L) and antimicrobial activity against microorganisms primarily responsible for the spoilage of frankfurters. In conclusion, the results indicate that the CFS contains high levels of bioactive metabolites, and an edible chitosan coating impregnated with CFS can be utilized to extend the shelf life of frankfurters through its antimicrobial effects and oxidation stabilization.

Postbiotics in oncology: science or science fiction?

The gut microbiome has been increasingly understood to play a critical role in carcinogenesis and cancer disease progression. The most recent research advancements have shown that different tools of microbiota manipulation contribute to gut microbiome-immune-oncology axis modulation, offering exciting opportunities for targeted interventions aimed at improving the efficacy of established anti-cancer therapy. Postbiotics are a new entry among the biotics showing beneficial effects on human health while not requiring living cells to obtain the health effect and therefore not subjected to food safety rules for live microorganisms. Postbiotics are recently defined as the "preparation of inanimate microorganisms and/or their components that confers a health benefit on the host" and have gradually become the focus of the scientific community. Since the beginning of research on this topic, numerous studies about postbiotics have been proven to strengthen the gut barrier, reduce inflammation, and promote antimicrobial activity. However, research on the potential application of cancer therapy is still at the early stages of its efforts to uncover all the secrets surrounding postbiotics. This review aims to increase our understanding of the anti-cancer effect of postbiotics throughout a "bibliographic journey" on the biological activity of their components, including exopolysaccharides, cell wall fragments, tryptophan metabolites, enzymes, bacterial lysates, extracellular vesicles, and short-chain fatty acids, highlighting their perspective as a new supportive therapeutic method of treatment and identifying the literature gaps where further research is needed.

Inhibitory effect of bioactive compounds derived from freeze-dried paraprobiotic of Pediococcus acidilactici against food-borne pathogens: In-vitro and food model studies

It was aimed to assess the antimicrobial potential of lyophilized/freeze-dried paraprobiotic (LP) of P. acidilactici against some food-borne pathogens under in-vitro conditions and food model, and determination of bioactive compounds that contribute to the antimicrobial activity of LP. For this purpose, minimum inhibitory concentration (MIC), inhibition zones were determined against Listeria monocytogenes, Salmonella Typhimurium and Escherichia coli O157:H7. The MIC value was 6.25 mg/mL and a 20 µL LP displayed 8.78 to 10.0 mm inhibition zones against these pathogens. In the food matrice challenge, two concentrations of LP (3% and 6%) alone or in combination with EDTA (0.02 M) were added to pathogenic bacteria spiked meatballs, and antimicrobial activity of LP was also determined during refrigerated storage. 6% LP + 0.02 M EDTA treatment provided 1.32 to 3.11 log₁₀ CFU/g reductions in the numbers of these pathogens (P < 0.05). Furthermore, this treatment provided significant reductions on psychrotrophs, TVC, LAB, mold-yeast, and Pseudomonas spp. over the storage (P < 0.05). Regarding characterization results, LP contained contained a wide variety of bioactive compounds, including 5 organic acids (2.15 to 30.64 g/100 g), 19 free amino acids (6.97 to 699.15 mg/100 g), free fatty acids (short-, medium-, and long-chain fatty acids), 15 polyphenols (0.03 to 383.78 mg/100 g), and some volatile compounds such as pyrazines, pyranone and pyrrole derivatives. These bioactive compounds are not only involved in antimicrobial activity but also contribute to the free radical scavenging activity according to the DPPH, ABTS and FRAP assays. In conclusion, the result revealed that the LP improved the chemical and microbiological quality of foods due to containing biologically-active metabolites involved in antimicrobial and antioxidant capacity.

Role of microbiota and microbiota-derived short-chain fatty acids in PDAC

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive lethal diseases among other cancer types. Gut microbiome and its metabolic regulation play a crucial role in PDAC. Metabolic regulation in the gut is a complex process that involves microbiome and microbiome-derived short-chain fatty acids (SCFAs). SCFAs regulate inflammation, as well as lipid and glucose metabolism, through different pathways. This review aims to summarize recent developments in PDAC in the context of gut and oral microbiota and their associations with short-chain fatty acid (SCFA). In addition to this, we discuss possible therapeutic applications using microbiota in PDAC.

Potential Role of ROS in Butyrate- and Dietary Fiber-Mediated Growth Inhibition and Modulation of Cell Cycle-, Apoptosis- and Antioxidant-Relevant Proteins in LT97 Colon Adenoma and HT29 Colon Carcinoma Cells

The aim of the present study was to examine whether reactive oxygen species (ROS) contribute to chemopreventive effects of fermentation supernatants (FS) of different dietary fibers (Synergy1^®, oat-, barley-, yeast β-glucan, Curdlan) and butyrate as a fermentation metabolite. LT97 and HT29 cells were treated with butyrate and FS alone or with N-acetyl-cysteine (NAC) and their impact on ROS formation, cell growth, and protein expression (Cyclin D2, p21, PARP, Bid, GPx2) was investigated. Butyrate and FS significantly decreased cell growth. ROS levels were significantly increased, particularly in LT97 cells, while co-treatment with NAC decreased ROS formation and growth inhibitory effects in both cell lines. After treatment with butyrate and FS, Cyclin D2 expression was reduced in LT97 cells and p21 expression was increased in both cell lines. Levels of full-length PARP and Bid were decreased, while levels of cleaved PARP were enhanced. GPx2 expression was significantly reduced by fiber FS in HT29 cells. A notable effect of NAC on butyrate- and FS-modulated protein expression was observed exclusively for PARP and Bid in HT29 cells. From the present results, a contribution of ROS to growth inhibitory and apoptotic effects of butyrate and FS on LT97 and HT29 cells cannot be excluded.

The Pivotal Role of the Gut Microbiome in Colorectal Cancer

Simple Summary

Colorectal cancer is a common form of cancer observed globally. It is thought that the gut microbiome may play a pivotal role in the development and progression of colorectal cancer in patients. Furthermore, current treatment strategies may lead to a variety of side effects, and chemotherapeutic resistance is observed. Consequently, new types of treatments should be considered, including post/pre/synbiotics and fecal microbiota transfer, which may be able to restore gut microbial dysbiosis.

Abstract

Colorectal cancer is the third most diagnosed cancer worldwide and the second most prevalent cause of cancer-related mortality. It is believed that alterations within the gut microbiome may impact the development and progression of cancer. Additionally, the diet an individual maintains and the amount of alcohol consumed can alter the microbiome, thus impacting the development of colorectal cancer. A diet focused on fiber intake is considered beneficial, as it contains short-chain fatty acids such as butyrate, which have antitumor properties. Furthermore, current treatment strategies, such as chemotherapy, have various side effects. In this review, we discuss the role of the gut microbiome and oral bacteria in relation to colorectal cancer. We also deliberate on the role of diet and alcohol consumption in the development of colorectal cancer. Moreover, the influence of the various metabolites within the gut and the importance of gut inflammation in the development of colorectal cancer are explained. Finally, potential therapies such as fecal microbiota transfer and post/prebiotics are elaborated on. To further comprehend risk factors in the development of colorectal cancer, future studies are warranted to determine the precise mechanisms of action between the gut microbiome and carcinogenesis in order to develop therapies that may target gut microbial dysbiosis.

Postbiotics versus probiotics in early-onset colorectal cancer

Probiotics and postbiotics mechanisms of action and applications in early-onset colorectal cancer (EOCRC) prevention and treatment have significant importance but are a matter of debate and controversy. Therefore, in this review, we aimed to define the probiotics concept, advantages and limitations in comparison to postbiotics, and proposed mechanisms of anti-tumor action in EOCRC prevention and treatment of postbiotics. Biotics (probiotics, prebiotics, and postbiotics) could confer the health benefit by affecting the host gut microbiota directly and indirectly. The main mechanisms of action of probiotics in exerting anticancer features include immune system regulation, inhibition of cancer cell propagation, gut dysbiosis restoration, anticancer agents' production, gut barrier function renovation, and cancer-promoting agents' reduction. Postbiotics are suggested to have different mechanisms of action to restore eubiosis against EOCRC, including modulation of gut microbiota composition, gut microbial metabolites regulation, and intestinal barrier function improvement via different features such as immunomodulatory, anti-inflammatory, antioxidant, and anti-proliferative properties. A better understanding of postbiotics challenges and mechanism of action in therapeutic applications will allow us to sketch accurate trials in order to use postbiotics as bio-therapeutics in EOCRC.

Probiotic-Based Intervention in the Treatment of Ulcerative Colitis: Conventional and New Approaches

Although there are number of available therapies for ulcerative colitis (UC), many patients are unresponsive to these treatments or experience secondary failure during treatment. Thus, the development of new therapies or alternative strategies with minimal side effects is inevitable. Strategies targeting dysbiosis of gut microbiota have been tested in the management of UC due to the unquestionable role of gut microbiota in the etiology of UC. Advanced molecular analyses of gut microbiomes revealed evident dysbiosis in UC patients, characterized by a reduced biodiversity of commensal microbiota. Administration of conventional probiotic strains is a commonly applied approach in the management of the disease to modify the gut microbiome, improve intestinal barrier integrity and function, and maintain a balanced immune response. However, conventional probiotics do not always provide the expected health benefits to a patient. Their benefits vary significantly, depending on the type and stage of the disease and the strain and dose of the probiotics administered. Their mechanism of action is also strain-dependent. Recently, new candidates for potential next-generation probiotics have been discovered. This could bring to light new approaches in the restoration of microbiome homeostasis and in UC treatment in a targeted manner. The aim of this paper is to provide an updated review on the current options of probiotic-based therapies, highlight the effective conventional probiotic strains, and outline the future possibilities of next-generation probiotic and postbiotic supplementation and fecal microbiota transplantation in the management of UC.

Postbiotics and Kidney Disease

Chronic kidney disease (CKD) is projected to become the fifth global cause of death by 2040 as a result of key shortcomings in the current methods available to diagnose and treat kidney diseases. In this regard, the novel holobiont concept, used to describe an individual host and its microbial community, may pave the way towards a better understanding of kidney disease pathogenesis and progression. Microbiota-modulating or -derived interventions include probiotics, prebiotics, synbiotics and postbiotics. As of 2019, the concept of postbiotics was updated by the International Scientific Association of Probiotics and Prebiotics (ISAPP) to refer to preparations of inanimate microorganisms and/or their components that confer a health benefit to the host. By explicitly excluding purified metabolites without a cellular biomass, any literature making use of such term is potentially rendered obsolete. We now review the revised concept of postbiotics concerning their potential clinical applications and research in kidney disease, by discussing in detail several formulations that are undergoing preclinical development such as GABA-salt for diet-induced hypertension and kidney injury, sonicated Lactobacillus paracasei in high fat diet-induced kidney injury, GABA-salt, lacto-GABA-salt and postbiotic-GABA-salt in acute kidney injury, and O. formigenes lysates for hyperoxaluria. Furthermore, we provide a roadmap for postbiotics research in kidney disease to expedite clinical translation.

Local and systemic effects of microbiome‐derived metabolites

Commensal microbes form distinct ecosystems within their mammalian hosts, collectively termed microbiomes. These indigenous microbial communities broadly expand the genomic and functional repertoire of their host and contribute to the formation of a “meta‐organism.” Importantly, microbiomes exert numerous biochemical reactions synthesizing or modifying multiple bioactive small molecules termed metabolites, which impact their host's physiology in a variety of contexts. Identifying and understanding molecular mechanisms of metabolite–host interactions, and how their disrupted signaling can contribute to diseases, may enable their therapeutic application, a modality termed “postbiotic” therapy. In this review, we highlight key examples of effects of bioactive microbe‐associated metabolites on local, systemic, and immune environments, and discuss how these may impact mammalian physiology and associated disorders. We outline the challenges and perspectives in understanding the potential activity and function of this plethora of microbially associated small molecules as well as possibilities to harness them toward the promotion of personalized precision therapeutic interventions.

The future of functional food: Emerging technologies application on prebiotics, probiotics and postbiotics

This review was the first to gather literature about the effect of emerging technologies on probiotic, prebiotic, and postbiotic products. Applying emerging technologies to probiotic products can increase probiotic survival and improve probiotic properties (cholesterol attachment, adhesion to Caco-2 cells, increase angiotensin-converting enzyme (ACE) inhibitory, antioxidant, and antimicrobial activities, and decrease systolic blood pressure). Furthermore, it can optimize the fermentation process, produce or maintain compounds of interest (bacteriocin, oligosaccharides, peptides, phenolic compounds, flavonoids), improve bioactivity (vitamin, aglycones, calcium), and sensory characteristics. Applying emerging technologies to prebiotic products did not result in prebiotic degradation. Still, it contributed to higher concentrations of bioactive compounds (citric and ascorbic acids, anthocyanin, polyphenols, flavonoids) and health properties (antioxidant activity and inhibition of ACE, α-amylase, and α-glucosidase). Emerging technologies may also be applied to obtain postbiotics with increased health effects. In this way, current studies suggest that emerging food processing technologies enhance the efficiency of probiotics and prebiotics in food. The information provided may help food industries to choose a more suitable technology to process their products and provide a basis for the most used process parameters. Furthermore, the current gaps are discussed. Emerging technologies may be used to process food products resulting in increased probiotic functionality, prebiotic stability, and higher concentrations of bioactive compounds. In addition, they can be used to obtain postbiotic products with improved health effects compared to the conventional heat treatment.

The Influence of Nutrition on Intestinal Permeability and the Microbiome in Health and Disease

The leakage of the intestinal barrier and the disruption of the gut microbiome are increasingly recognized as key factors in different pathophysiological conditions, such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), chronic liver diseases, obesity, diabetes mellitus, types of cancer, and neuropsychiatric disorders. In this study, the mechanisms leading to dysbiosis and "leaky gut" are reviewed, and a short summary of the current knowledge regarding different diseases is provided. The simplest way to restore intestinal permeability and the microbiota could be ideal nutrition. Further therapeutic options are also available, such as the administration of probiotics or postbiotics or fecal microbiota transplantation.