Consumption of β-glucans to spice up T cell treatment of tumors: a review

The use of Pleurotus ostreatus by-products for the preparation of a gel-like polysaccharide with bioactive properties

The mushroom Pleurotus ostreatus is widely produced in Brazil and its stipes are discarded before commercialization. In the present study, this agricultural fungal waste (mushroom stipes), was analyzed by preparing an aqueous extract and obtaining the polysaccharides by ethanol precipitation (POS-extract). The fraction presented 37 % of carbohydrates and small amounts of proteins and phenolic compounds. Rheological analyses showed a high viscosity and a gel-like behavior depending on temperature and concentration. The main polysaccharides present were β-glucans and mannogalactans, which were confirmed by the enzymatic method, monosaccharide composition, and NMR. Methylation analyses showed a high content of 1,6-linkages for both polysaccharides. The POS-extract was tested on Caco-2 cells to observe cytotoxicity and cell migration ability. Incubation with different concentrations of POS-extract showed no significant cytotoxic effects (p ≥ 0.05) and promoted wound closure of the injured monolayer by 95 % after 72 h (at 300 μg/mL). The preliminary results indicate a promising application of mushroom by-products, containing easily extractable bioactive compounds.

Improving functional and nutritional profiles of barley flours with diverse starch types through pearling

A comparative analysis of chemical, functional, and digestive parameters was conducted on five new barley genotypes designed for food purposes, differing in starch type, β-glucans, and arabinoxylan content. Both whole and pearled grain flours were examined. Amylose exhibited positive correlations with least gelation capacity (r = 0.60), gelation temperature (r = 0.90), and resistant starch (r = 0.80). Waxy varieties showed greater water-holding capacity, viscosity, and rapid digestibility compared to normal and high-amylose varieties. Pearling (10%) decreased arabinoxylans by 48% and proteins by 7%, while increasing β-glucans by 8% and starch by 13%. Additionally, pearling improved viscosity and hydration parameters across varieties. This allowed normal and high-amylose genotypes to enhance their functional properties and nutritional value through increased β-glucan and resistant starch content. This exploration advances the understanding of barley's functional attributes for food industry and underscores the potential of pearling to augment consumer nutritional value and health-promoting properties.

Structural properties, bioactivities, structure-activity relationships and bio-applications of polysaccharides from Auricularia auricula: A review

Auricularia auricula (A. auricula), is a medicinal and edible fungus in China for thousands of years with rich nutrition and delicious taste. The main active ingredient of A. auricula is polysaccharide, which has antitumor, hypoglycemic, antioxidant, and immune regulation bioactivities. It is widely recognized that the biological activity of polysaccharides is closely related to the chemical structure and advanced structure. In terms of polysaccharides extracted from A. auricula (AAPs), there were distinguished structures reported due to the different original resources and extraction methods, leading to various bioactivities. However, the structure-activity relationship of AAPs has scarcely been reviewed till now. In addition, polysaccharides were found to have specific self-assembly properties recently, together with their bioactivities, endowing them with unique physicochemical properties. Nowadays, an increasing number of polysaccharides, such as cellulose, chitin, and pectin, have been used to construct various functional materials in the fields of food, cosmetics, and biomedical materials. Therefore, the construction of functional materials by AAPs is of great research significance. This article aims to provide a systematic review of the structure-activity relationship of AAPs and summarize the functional materials constructed based on AAPs to provide theoretical references for further research and application of AAPs.

Potential promising anticancer applications of β-glucans: a review

β-Glucans are valuable functional polysaccharides distributed in nature, especially in the cell walls of fungi, yeasts, bacteria, and cereals. The unique features of β-glucans, such as water solubility, viscosity, molecular weight, and so on, have rendered them to be broadly applied in various food systems as well as in medicine to improve human health. Moreover, inhibition of cancer development could be achieved by an increase in immune system activity via β-glucans. β-glucans, which are part of a class of naturally occurring substances known as biological response modifiers (BRMs), have also shown evidence of being anti-tumorogenic, anti-cytotoxic, and anti-mutagenic. These properties make them attractive candidates for use as pharmaceutical health promoters. Along these lines, they could activate particular proteins or receptors, like lactosylceramide (LacCer), Dickin-1, complement receptor 3 (CR3), scavenge receptors (SR), and the toll-like receptor (TLR). This would cause the release of cytokines, which would then activate other antitumor immune cells, like macrophages stimulating neutrophils and monocytes. These cells are biased toward pro-inflammatory cytokine synthesis and phagocytosis enhancing the elicited immunological responses. So, to consider the importance of β-glucans, the present review introduces the structure characteristics, biological activity, and antitumor functions of fungal β-glucans, as well as their application.

How do tumours outside the gastrointestinal tract respond to dietary fibre supplementation?

Cancer remains one of the leading causes of death worldwide, despite advances in treatments such as surgery, chemotherapy, radiotherapy and immunotherapy. The role of the gut microbiota in human health and disease, particularly in relation to cancer incidence and treatment response, has gained increasing attention. Emerging evidence suggests that dietary fibre, including prebiotics, can modulate the gut microbiota and influence antitumour effects. In this review, we provide an overview of how dietary fibre impacts the gut-tumour axis through immune and non-immune mechanisms. Preclinical evidence shows that β-glucan or inulin effectively suppress extraintestinal tumour growth via immunomodulation. Other fibres such as resistant starch, modified citrus pectin and rye bran may confer antitumour effects through metabolic regulation, production of metabolites or downregulation of the insulin/insulin-like growth factor 1 axis. Additionally, we highlight the potential for dietary fibre to modify the response to immunotherapy, chemotherapy and radiotherapy, as shown by inulin increasing the abundance of beneficial gut bacteria, such as Bifidobacterium, Akkermansia, Lactobacillus and Faecalibacterium prausnitzii, which have been associated with enhanced immunotherapy outcomes, particularly in melanoma-bearing mice. Furthermore, certain types of dietary fibre, such as psyllium, partially hydrolysed guar gum, hydrolysed rice bran and inulin plus fructooligosaccharide, have been shown to mitigate gastrointestinal toxicities in patients with cancer undergoing pelvic radiotherapy. Despite the proven benefits, it is noteworthy that most adults do not consume enough dietary fibre, underscoring the importance of promoting dietary fibre supplementation in patients with cancer to optimise their treatment responses.

Immune-Stimulating Potential of Lacticaseibacillus rhamnosus LM1019 in RAW 264.7 Cells and Immunosuppressed Mice Induced by Cyclophosphamide

Probiotics, including Lacticaseibacillus rhamnosus (L. rhamnosus), have gained recognition for their potential health benefits, such as enhancing immune function, maintaining gut health, and improving nutrient absorption. This study investigated the effectiveness of L. rhamnosus LM1019 (LM1019) in enhancing immune function. In RAW 264.7 cells, LM1019 demonstrated dose-dependent immune stimulation by increasing nitric oxide production, gene expression of proinflammatory cytokines, and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2). These effects were mediated through the activation of mitogen-activated protein kinases (MAPKs) and nuclear factor-kappa B (NF-κB) translocation without inducing cytotoxicity. Furthermore, orally administered LM1019 was evaluated in immunosuppressed mice induced by cyclophosphamide (CTX). High-dose administration of LM1019 significantly increased the subpopulations of lymphocytes, specifically helper T cells (CD4+), as well as two subtypes of natural killer (NK) cells, namely, IFN-γ+ and granzyme B+ NK cells. Additionally, LM1019 at a high dose led to elevated levels of proinflammatory cytokines, including IFN-γ and IL-12, compared to CTX-treated mice. These findings highlight the potential of LM1019 in enhancing the immune system. The study contributes to the growing body of research on the beneficial effects of probiotics on immune function.

Beta glucan as an immune stimulant in tumor microenvironment - Insight into lessons and promises from past decade

Cancer is characterized by a perturbed immune landscape. Inside tumor microenvironment, immune system is reprogrammed to facilitate tumor growth and survival rather than eliminating it. This immune evasive mechanism needs to be reversed to normal for effective anticancer therapeutic strategy. Immunotherapy has emerged as a novel strategy for redeployment of immune cells against cancer. However, they suffer in their efficacy, response rate and side effects. This necessitated us to turn toward natural repertoires which can act as a substitute to conventional immunotherapeutics. Beta glucan, a polysaccharide derived from mushroom, serves the role of immunomodulator inside tumor microenvironment. It acts as pathogen associated molecular pattern and bind to various pattern recognition receptors expressed on surface of immune cells thereby facilitating their activation and crosstalk. This result in resurgence of suppressed immune surveillance in the tumor milieu. In this review, we highlight in brief the advances and limitation of cancer immunotherapy. Alongside, we have discussed the detailed mechanistic principle and recent advances underlying restoration of immune functionality by beta glucan.

PD-L1 antibody enhanced β-glucan antitumor effects via blockade of the immune checkpoints in a melanoma model

In the tumor microenvironment (TME), one of the major functions of tumor-recruited CD11b⁺ cells are the suppression of the T-cell-mediated anti-tumor immune response. β-glucan could convert the phenotype of tumor-recruited CD11b⁺ cells from the suppressive to the promotive, and enhanced their anti-tumor effects. However, β-glucan could enhance the PD-1/PD-L1 expression on CD11b⁺ cells, while PD-1 could inhibit macrophage phagocytosis and PD-L1 could induce a co-inhibitory signal in T-cells and lead to T-cell apoptosis and anergy. These protumor effects may be reversed by PD-1/PD-L1 block therapy. In the present study, we focused on the efficacy of β-glucan anti-tumor therapy combined with anti-PD-L1 mAb treatment, and the mechanism of their synergistic effects could be fully verified. We verified the effect of β-glucan (i.e., inflammatory cytokine secretion of TNF-α, IL-12, IL-6, IL-1β and the expression of immune checkpoint PD-1/PD-L1) in naïve mouse peritoneal exudate CD11b⁺ cells. In our mouse melanoma model, treatment with a PD-L1 blocking antibody with β-glucan synergized tumor regression. After treatment with β-glucan and anti-PD-L1 mAb antibody, tumor infiltrating leukocyte (TILs) not only showed a competent T-cell function (CD107a, perforin, IL-2, IFN-γ and Ki67) and CTL population, but also showed enhanced tumor-recruited CD11b⁺ cell activity (IL-12, IL-6, IL-1β and PD-1). This effect was also verified in the peritoneal exudate CD11b⁺ cells of tumor-bearing mice. PD-1/PD-L1 blockade therapy enhanced the β-glucan antitumor effects via the blockade of tumor-recruited CD11b⁺ cell immune checkpoints in the melanoma model.

Mechanism-Driven and Clinically Focused Development of Botanical Foods as Multitarget Anticancer Medicine: Collective Perspectives and Insights from Preclinical Studies, IND Applications and Early-Phase Clinical Trials

Cancer progression and mortality remain challenging because of current obstacles and limitations in cancer treatment. Continuous efforts are being made to explore complementary and alternative approaches to alleviate the suffering of cancer patients. Epidemiological and nutritional studies have indicated that consuming botanical foods is linked to a lower risk of cancer incidence and/or improved cancer prognosis after diagnosis. From these observations, a variety of preclinical and clinical studies have been carried out to evaluate the potential of botanical food products as anticancer medicines. Unfortunately, many investigations have been poorly designed, and encouraging preclinical results have not been translated into clinical success. Botanical products contain a wide variety of chemicals, making them more difficult to study than traditional drugs. In this review, with the consideration of the regulatory framework of the USFDA, we share our collective experiences and lessons learned from 20 years of defining anticancer foods, focusing on the critical aspects of preclinical studies that are required for an IND application, as well as the checkpoints needed for early-phase clinical trials. We recommend a developmental pipeline that is based on mechanisms and clinical considerations.

Use of Microorganisms as Nutritional and Functional Feedstuffs for Nursery Pigs and Broilers

The objectives of this review paper are to introduce the structures and composition of various microorganisms, to show some applications of single cells as alternative protein supplements or energy feeds in swine and poultry diets, and to discuss the functional effects of microorganisms as feed additives on the growth performance and intestinal health of nursery pigs and broilers. Microorganisms, including bacteria, yeasts, and microalgae, have been commonly supplemented in animal diets because they are cost-effective, stable, and have quantitative production that provides nutritional and functional benefits to pigs and broilers. Microorganisms could be alternative antibiotics to enhance intestinal health due to bioactive components from cell wall components, which interact with receptors on epithelial and immune cells. In addition, bioactive components could be digested by intestinal microbiota to produce short-chain fatty acids and enhance energy utilization. Otherwise, microorganisms such as single-cell protein (SCP) and single-cell oils (SCOs) are sustainable and economic choices to replace conventional protein supplements and energy feeds. Supplementing microorganisms as feedstuffs and feed additives improved the average daily gain by 1.83%, the daily feed intake by 0.24%, and the feed efficiency by 1.46% in pigs and broilers. Based on the properties of each microorganism, traditional protein supplements, energy feeds, and functional feed additives could be replaced by microorganisms, which have shown benefits to animal's growth and health. Therefore, specific microorganisms could be promising alternatives as nutritional and functional feedstuffs in animal diets.

Polarization and β-Glucan Reprogram Immunomodulatory Metabolism in Human Macrophages and Ex Vivo in Human Lung Cancer Tissues

Immunomodulatory (IM) metabolic reprogramming in macrophages (Mϕs) is fundamental to immune function. However, limited information is available for human Mϕs, particularly in response plasticity, which is critical to understanding the variable efficacy of immunotherapies in cancer patients. We carried out an in-depth analysis by combining multiplex stable isotope-resolved metabolomics with reversed phase protein array to map the dynamic changes of the IM metabolic network and key protein regulators in four human donors' Mϕs in response to differential polarization and M1 repolarizer β-glucan (whole glucan particles [WGPs]). These responses were compared with those of WGP-treated ex vivo organotypic tissue cultures (OTCs) of human non-small cell lung cancer. We found consistently enhanced tryptophan catabolism with blocked NAD+ and UTP synthesis in M1-type Mϕs (M1-Mϕs), which was associated with immune activation evidenced by increased release of IL-1β/CXCL10/IFN-γ/TNF-α and reduced phagocytosis. In M2a-Mϕs, WGP treatment of M2a-Mϕs robustly increased glucose utilization via the glycolysis/oxidative branch of the pentose phosphate pathway while enhancing UDP-N-acetyl-glucosamine turnover and glutamine-fueled gluconeogenesis, which was accompanied by the release of proinflammatory IL-1β/TNF-α to above M1-Mϕ's levels, anti-inflammatory IL-10 to above M2a-Mϕ's levels, and attenuated phagocytosis. These IM metabolic responses could underlie the opposing effects of WGP, i.e., reverting M2- to M1-type immune functions but also boosting anti-inflammation. Variable reprogrammed Krebs cycle and glutamine-fueled synthesis of UTP in WGP-treated OTCs of human non-small cell lung cancer were observed, reflecting variable M1 repolarization of tumor-associated Mϕs. This was supported by correlation with IL-1β/TNF-α release and compromised tumor status, making patient-derived OTCs unique models for studying variable immunotherapeutic efficacy in cancer patients.

β-Glucan as a Techno-Functional Ingredient in Dairy and Milk-Based Products-A Review

The article systematizes information about the sources of β-glucan, its technological functions and practical aspects of its use in dairy and milk-based products. According to the analysis of scientific information, the main characteristics of β-glucan classifications were considered: the source of origin, chemical structure, and methods of obtention. It has been established that the most popular in the food technology of dairy products are β-glucans from oat and barley cereal, which exhibit pronounced technological functions in the composition of dairy products (gel formation, high moisture-binding capacity, increased yield of finished products, formation of texture, and original sensory indicators). The expediency of using β-glucan from yeast and mushrooms as a source of biologically active substances that ensure the functional orientation of the finished product has been revealed. For the first time, information on the use of β-glucan of various origins in the most common groups of dairy and milk-based products has been systematized. The analytical review has scientific and practical significance for scientists and specialists in the field of food production, in particular dairy products of increased nutritional value.

Dectin-1b activation by arabinoxylans induces trained immunity in human monocyte-derived macrophages

Arabinoxylans of various structures and sources have shown to possess the ability to induce a range of immune responses in different cell types in vitro and in vivo. Although the underlying mechanisms remain to be fully established, several studies point towards the involvement of activation of pattern recognition receptors (PRRs). Activation of specific PRRs (i.e., Dectin-1 and CR3) has also been shown to play a key role in the induction of a non-specific memory response in innate immune cells, termed 'trained innate immunity'. In the current study, we assessed whether arabinoxylans are also able to induce trained innate immunity. To this end, a range of arabinoxylan preparations from different sources were tested for their physicochemical properties and their capacity to induce innate immune training and resilience. In human macrophages, rice and wheat-derived arabinoxylan preparations induced training and/or resilience effects, the extent depending on fiber particle size and solubility. Using a Dectin-1 antagonist or a CR3 antibody, it was demonstrated that arabinoxylan-induced trained immunity in macrophages is mainly dependent on Dectin-1b. These findings build on previous observations showing the immunomodulatory potential of arabinoxylans as biological response modifiers and open up promising avenues for their use as health promoting ingredients.

β-glucan from Aureobasidium pullulans augments the anti-tumor immune responses through activated tumor-associated dendritic cells

Dendritic cells (DCs) are recognized as the most potent antigen-presenting cells, capable of priming both naïve and memory T cells. Thus, tumor-resident DCs (tumor-associated DCs: TADCs) play a crucial role in the immune response against tumors. However, TADCs are also well known as a "double-edged sword" because an immunosuppressive environment, such as a tumor microenvironment, maintains the immature and tolerogenic properties of TADCs, resulting in the deterioration of the tumor. Therefore, it is essential to maintain and enhance the anti-tumoral activity of TADCs to aid tumor elimination. This study demonstrated the potential for tumor growth inhibition of Aureobasidium pullulan-derived β-glucan (AP-BG). Administration of AP-BG dramatically limited the development of different types of tumor cell lines transplanted into mice. Examination of the tumor-infiltrating leukocytes revealed that AP-BG caused high expression of co-stimulatory molecules on TADCs and enhanced the production of cytolytic granules as well as pro-inflammatory cytokines by the tumor-resident T cells. Furthermore, the syngeneic mixed lymphoid reaction assay and popliteal lymph node assay showed the significant ability of AP-BG to improve DCs' antigen-specific priming of T cells in vitro and in vivo. Taken together, β-glucan might be an immune-potentiating adjuvant for cancer treatment. This highly widely-used reagent will initiate a new way to activate DC-targeted cancer immune therapy.

Protective role of yeast beta-glucan on lead acetate-induced hepatic and reproductive toxicity in rats

Lead (Pb) is one of the most common environmental pollutants and causes adverse effects on human and animal health. This study aimed to evaluate the protective role of beta-glucan against hepatic and reproductive toxicity induced by lead acetate. A total of 28 Sprague Dawley male rats were distributed into four groups (n = 7). The control group was intraperitoneally injected saline (1 ml/kg b.w.) daily for 21 days, the Pb group was intraperitoneally injected lead acetate (15 mg/kg b.w.) daily for 21 days, the beta-glucan group was orally administrated beta-glucan (50 mg/kg b.w.) daily for 21 days, and the Pb + beta-glucan group was intraperitoneally injected lead acetate (15 mg/kg b.w.) daily following the oral administration of beta-glucan (50 mg/kg b.w.) daily for 21 days. Results showed that feed intake in the Pb + beta-glucan group was significantly increased in comparison with that of the Pb group (p < 0.001). We also found that liver malondialdehyde (MDA) level was increased significantly in the Pb group (p < 0.01), while glutathione (GSH) level (p < 0.05), glutathione peroxidase (GSH-Px) (p < 0.05), and catalase (CAT) (p < 0.01) activities were reduced when they were compared with control. Moreover, Pb administration increased expression of pro-apoptotic protein Bax, the ratio of Bax/Bcl-2, and decreased the expression of the antiapoptotic protein Bcl-2 (p < 0.01). Also, Pb was found to cause a significant decrease in sperm motility (p < 0.01) and sperm concentration (p < 0.05) but increase in sperm tails and total sperm anomalies (p < 0.05). These findings were partially preserved by the administration of beta-glucan. Taken together, these results indicated that beta-glucan has the potential to alleviate the Pb-induced toxicity.

Beta-glucans is a potential inhibitor of ovarian cancer: based on molecular and biological aspects

Ovarian cancer is a lethal type of cancer which is initiated in the ovaries and affects 1 out of every 75 women. Due to the high number of deaths (almost 152,000) related to this cancer, it seems that novel effiecient therapeutic methods are required in this field. Beta-glucans are a type of glucose linear polymers which have proven to have a lot of advantageous activities. Recently, investigations have declared that these polysaccharides have the potential to be used as anti-cancer drugs. These agents are able to affect several mechanisms such as inflammation and apoptosis and that is how cancers are prone to be affected by them. In this review, we attempt to investigate the role of beta-glucans on ovarian cancer. We hope that this paper might give novel insights in the field of ovarian cancer treatment.

Continuous Exposure to Non-Soluble β-Glucans Induces Trained Immunity in M-CSF-Differentiated Macrophages

Beta-glucans enable functional reprogramming of innate immune cells, a process defined as "trained immunity", which results in enhanced host responsiveness against primary (training) and/or secondary infections (resilience). Trained immunity holds great promise for promoting immune responses in groups that are at risk (e.g. elderly and patients). In this study, we modified an existing in vitro model for trained immunity by actively inducing monocyte-to-macrophage differentiation using M-CSF and applying continuous exposure. This model reflects mucosal exposure to β-glucans and was used to study the training effects of a variety of soluble or non-soluble β-glucans derived from different sources including oat, mushrooms and yeast. In addition, trained immunity effects were related to pattern recognition receptor usage, to which end, we analyzed β-glucan-mediated Dectin-1 activation. We demonstrated that β-glucans, with different sources and solubilities, induced training and/or resilience effects. Notably, trained immunity significantly correlated with Dectin-1 receptor activation, yet Dectin-1 receptor activation did not perform as a sole predictor for β-glucan-mediated trained immunity. The model, as validated in this study, adds on to the existing in vitro model by specifically investigating macrophage responses and can be applied to select non-digestible dietary polysaccharides and other components for their potential to induce trained immunity.

Impact of Rising Temperature in the Deposition Patterns of Bioactive Compounds in Field Grown Food Barley Grains

High temperatures at the end of the season are frequent under Mediterranean conditions, affecting final grain quality. This study determined the deposition patterns throughout grain filling of dry matter, dietary fiber, phenolic compounds and antioxidant capacity for four barley genotypes under two contrasting temperatures. Deposition pattern for dietary fiber followed that of grain weight. Genotypic differences for duration were more significant than for rate. Anthocyanins followed a second-degree polynomial pattern, reaching a maximum before grain maturation. Free and bound phenols decreased as grain developed, suggesting that they are synthesized in early stages. Rate of bound phenols deposition was more sensitive to genotypic changes. Overall, antioxidant capacity decreased over time; the decay being less steep under stress for all genotypes. Heat stress negatively affected grain weight. It did not alter the profile of β-glucans and arabinoxylans deposition but positively changed the accumulation of some phenolic compounds, increasing the antioxidant capacity differentially across genotypes. These results support the growing of food barley in high-temperature stress-prone areas, as some bioactive compound and antioxidant capacity will increase, regardless of the smaller grain size. Moreover, if a market develops for food-barley ingredients, early harvesting of non-mature grain to maximize antioxidant capacity should be considered.

Bioactive Compounds and Antioxidant Capacity in Pearling Fractions of Hulled, Partially Hull-Less and Hull-Less Food Barley Genotypes

Three food barley genotypes differing in the presence or absence of husks were sequentially pearled and their fractions analyzed for ash, proteins, bioactive compounds and antioxidant capacity in order to identify potential functional food ingredients. Husks were high in ash, arabinoxylans, procyanidin B3, prodelphinidin B4 and p-coumaric, ferulic and diferulic bound acids, resulting in a high antioxidant capacity. The outermost layers provided a similar content of those bioactive compounds and antioxidant capacity that were high in husks, and also an elevated content of tocols, representing the most valuable source of bioactive compounds. Intermediate layers provided high protein content, β-glucans, tocopherols and such phenolic compounds as catechins and bound hydroxybenzoic acid. The endosperm had very high β-glucan content and relative high levels of catechins and hydroxybenzoic acid. Based on the spatial distribution of the bioactive compounds, the outermost 30% pearling fractions seem the best option to exploit the antioxidant capacity of barley to the full, whereas pearled grains supply β-glucans enriched flours. Current regulations require elimination of inedible husks from human foods. However, due to their high content in bioactive compounds and antioxidant capacity, they should be considered as a valuable material, at least for animal feeds.

Curdlan, zymosan and a yeast-derived β-glucan reshape tumor-associated macrophages into producers of inflammatory chemo-attractants

Anti-cancer T-cell responses are often halted due to the immune-suppressive micro-environment, in part related to tumor-associated macrophages. In the current study, we assessed indigestible β-glucans (oatβG, curdlan, grifolan, schizophyllan, lentinan, yeast whole glucan particles (yWGP), zymosan and two additional yeast-derived β-glucans a and b) for their physicochemical properties as well as their effects on the plasticity of human monocyte-derived macrophages that were polarized with IL-4 to immune-suppressive macrophages. Beta-glucans were LPS/LTA free, and tested for solubility, molecular masses, protein and monosaccharide contents. Curdlan, yeast-b and zymosan re-polarized M(IL-4) macrophages towards an M1-like phenotype, in particular showing enhanced gene expression of CCR7, ICAM1 and CD80, and secretion of TNF-α and IL-6. Notably, differential gene expression, pathway analysis as well as protein expressions demonstrated that M(IL-4) macrophages treated with curdlan, yeast-b or zymosan demonstrated enhanced production of chemo-attractants, such as CCL3, CCL4, and CXCL8, which contribute to recruitment of monocytes and neutrophils. The secretion of chemo-attractants was confirmed when using patient-derived melanoma-infiltrating immune cells. Taken together, the bacterial-derived curdlan as well as the yeast-derived β-glucans yeast-b and zymosan have the unique ability to preferentially skew macrophages towards a chemo-attractant-producing phenotype that may aid in anti-cancer immune responses.

In Vitro Studies Toward the Use of Chitin as Nutraceutical: Impact on the Intestinal Epithelium, Macrophages, and Microbiota

SCOPE

Chitin, the most abundant polysaccharide found in nature after cellulose, is known for its ability to support wound healing and to lower plasma-oxidized low-density lipoprotein (LDL) levels. Studies have also revealed immunomodulatory potential but contradicting results are often impossible to coalesce through usage of chitin of different or unknown physicochemical consistency. In addition, only a limited set of cellular models have been used to test the bioactivity of chitin.

METHODS AND RESULTS

Chitin is investigated with well-defined physicochemical consistency for its immunomodulatory potency using THP-1 macrophages, impact on intestinal epithelial barrier using Caco-2 cells, and fermentation by fecal-derived microbiota. Results show that chitin with a degree of acetylation (DA) of ≈83%, regardless of size, does not affect the intestinal epithelial barrier integrity. Large-sized chitin significantly increases acetic acid production by gut microbiota without altering the composition. Exposure of small-sized chitin to THP-1 macrophages lead to significantly increased secretion of IL-1β, IL-8, IL-10, and CXCL10 in a multi-receptor and clathrin-mediated endocytosis dependent manner.

CONCLUSIONS

These findings indicate that small-sized chitin does not harm the intestinal barrier nor affects SCFA secretion and microbiota composition, but does impact immune activity which could be beneficial to subjects in need of immune support or activation.

Fungal beta-glucans as adjuvants for treating cancer patients - A systematic review of clinical trials

BACKGROUND & AIMS

Fungal β-glucans have been considered as biological response modifiers (BRMs) promoting stimulation of immune system according to numerous scientific publications performed in vitro and in vivo. Some clinical trials involving such compounds started to be published since 1980's. This systematic review aimed to compile and compare clinical studies using these β-glucans as adjuvants on patients undergoing cancer treatment. Healthy subjects and β-glucans from other sources were excluded.

METHODS

It was developed according to PRISMA-P guidelines (PROSPERO registered n. CRD42020151539), using PICO criteria and the following databases: PubMed, Scielo and LILACS.

RESULTS

We found 1018 articles and after removing duplicated records, select by title/abstract and full-text, only 9 studies remained and 7 more were manually added, totalizing 16 trials involving 1650 patients, with arm sizes varying from 9 until 200 patients. The selected studies (published since 1992-2018) included subjects with diagnosis of 9 types of cancer. The studies used different sources of β-glucans, such as yeast (Saccharomyces cerevisiae), mushrooms (Lentinula edodes and Schizophyllum commune) and non-described fungal sources.

CONCLUSIONS

It was observed that the administration of β-glucan is safe and well-tolerated. Most of the trials pointed that concomitant administration of β-glucan with chemo or radiotherapy reduced the immune depression caused by such treatments and/or accelerated the recovery of white blood cells counts. However, some articles also commented that no statistical difference was encountered between β-glucan treated vs. control groups, which gives a controversial conclusion about the β-glucan effects. The great diversity among the methodology studies and insufficient information was an impeditive for achieving profound statistical analysis, therefore a narrative report of the included studies was performed indicating that further evidences are required to determine the efficacy of this adjuvant in the cancer treatment.

Targeting the tumor immune microenvironment with "nutraceuticals": From bench to clinical trials

The occurrence of immune effector cells in the tissue microenvironment during neoplastic progression is critical in determining tumor growth outcomes. On the other hand, tumors may also avoid immune system-mediated elimination by recruiting immunosuppressive leukocytes and soluble factors, which coordinate a tumor microenvironment that counteracts the efficiency of the antitumor immune response. Checkpoint inhibitor therapy results have indicated a way forward via activation of the immune system against cancer. Widespread evidence has shown that different compounds in foods, when administered as purified substances, can act as immunomodulators in humans and animals. Although there is no universally accepted definition of nutraceuticals, the term identifies a wide category of natural compounds that may impact health and disease statuses and includes purified substances from natural sources, plant extracts, dietary supplements, vitamins, phytonutrients, and various products with combinations of functional ingredients. In this review, we summarize the current knowledge on the immunomodulatory effects of nutraceuticals with a special focus on the cancer microenvironment, highlighting the conceptual benefits or drawbacks and subtle cell-specific effects of nutraceuticals for envisioning future therapies employing nutraceuticals as chemoadjuvants.

Wheat-derived arabinoxylans reduced M2-macrophage functional activity, but enhanced monocyte-recruitment capacity

The immunomodulatory properties of non-digestible polysaccharides (NDPs) have been recognized in in vitro and in vivo studies. The latter mostly demonstrated altered frequencies and inflammatory status of immune cells as clinical parameters. Most of the NDP activity will be exerted in the intestine where they can directly interact with macrophages. The predominant macrophage phenotype in the intestine is M2-like, with M1-like macrophages arising during inflammation. Here, we investigated transcriptional and functional impact on these macrophage phenotypes by NDP-treatment (i.e. yeast-derived soluble β-glucan (yeast-βG), apple-derived RG-I (apple-RGI), shiitake-derived β-glucan (shiitake-βG) or wheat-derived arabinoxylan (wheat-AX)). Wheat-AX, and to a lesser extent shiitake-βG and apple-RGI but not yeast-βG, reduced endocytosis and antigen processing capacity of M1- and M2-like macrophages. Moreover, the NDPs, and most notably wheat-AX, strongly induced transcription and secretion of a unique set of cytokines and chemokines. Conditioned medium from wheat-AX-treated M2-like macrophages subsequently demonstrated strongly increased monocyte recruitment capacity. These findings are in line with clinically observed immunomodulatory aspects of NDPs making it tempting to speculate that clinical activity of some NDPs is mediated through enhanced chemoattraction and modifying activity of intestinal immune cells.

Could the Induction of Trained Immunity by β-Glucan Serve as a Defense Against COVID-19?

As the SARS-CoV-2 virus wreaks havoc on the populations, health care infrastructures and economies of nations around the world, finding ways to protect health care workers and bolster immune responses in the general population while we await an effective vaccine will be the difference between life and death for many people. Recent studies show that innate immune populations may possess a form of memory, termed Trained Immunity (TRIM), where innate immune cells undergo metabolic, mitochondrial, and epigenetic reprogramming following exposure to an initial stimulus that results in a memory phenotype of enhanced immune responses when exposed to a secondary, heterologous, stimulus. Throughout the literature, it has been shown that the induction of TRIM using such inducers as the BCG vaccine and β-glucan can provide protection through altered immune responses against a range of viral infections. Here we hypothesize a potential role for β-glucan in decreasing worldwide morbidity and mortality due to COVID-19, and posit several ideas as to how TRIM may actually shape the observed epidemiological phenomena related to COVID-19. We also evaluate the potential effects of β-glucan in relation to the immune dysregulation and cytokine storm observed in COVID-19. Ultimately, we hypothesize that the use of oral β-glucan in a prophylactic setting could be an effective way to boost immune responses and abrogate symptoms in COVID-19, though clinical trials are necessary to confirm the efficacy of this treatment and to further examine differential effects of β-glucan's from various sources.

Oncolytic adenovirus ORCA-010 increases the type 1 T cell stimulatory capacity of melanoma-conditioned dendritic cells

Immune checkpoint blockade has resulted in durable responses in patients with metastatic melanoma, but only in a fraction of treated patients. For immune checkpoint inhibitors (ICI) to be effective, sufficient infiltration with tumor‐reactive T cells is essential. Oncolytic viruses (OV) selectively replicate in and lyse tumor cells and so induce an immunogenic form of cell death, providing at once a source of tumor‐associated (neo)antigens and of danger signals that together induce effective T cell immunity and tumor infiltration. Melanoma‐associated suppression of dendritic cell (DC) differentiation effectively hampers OV‐ or immune checkpoint inhibitor (ICI)‐induced anti‐tumor immunity, due to a consequent inability to prime and attract anti‐tumor effector T cells. Here, we set out to study the effect of ORCA‐010, a clinical stage oncolytic adenovirus, on DC differentiation and functionality in the context of human melanoma. In melanoma and monocyte co‐cultures, employing a panel of five melanoma cell lines with varying origins and oncogenic mutation status, we observed clear suppression of DC development with apparent skewing of monocyte differentiation to a more M2‐macrophage‐like state. We established the ability of ORCA‐010 to productively infect and lyse the melanoma cells. Moreover, although ORCA‐010 was unable to restore DC differentiation, it induced activation and an increased co‐stimulatory capacity of monocyte‐derived antigen‐presenting cells. Their subsequent ability to prime effector T cells with a type I cytokine profile was significantly increased in an allogeneic mixed leukocyte reaction. Our findings suggest that ORCA‐010 is a valuable immunotherapeutic agent for melanoma.

Dietary restriction of amino acids for Cancer therapy

Biosyntheses of proteins, nucleotides and fatty acids, are essential for the malignant proliferation and survival of cancer cells. Cumulating research findings show that amino acid restrictions are potential strategies for cancer interventions. Meanwhile, dietary strategies are popular among cancer patients. However, there is still lacking solid rationale to clarify what is the best strategy, why and how it is. Here, integrated analyses and comprehensive summaries for the abundances, signalling and functions of amino acids in proteomes, metabolism, immunity and food compositions, suggest that, intermittent dietary lysine restriction with normal maize as an intermittent staple food for days or weeks, might have the value and potential for cancer prevention or therapy. Moreover, dietary supplements were also discussed for cancer cachexia including dietary immunomodulatory.

Recent Advances in Chain Conformation and Bioactivities of Triple-Helix Polysaccharides

Natural polysaccharides derived from renewable biomass sources are regarded as environmentally friendly and sustainable polymers. As the third most abundant biomacromolecule in nature, after proteins and nucleic acids, polysaccharides are also closely related with many different life activities. In particular, β-glucans are one of the most widely reported bioactive polysaccharides and are usually considered as biological response modifiers. Among them, β-glucans with triple-helix conformation have been the hottest and most well-researched polysaccharides at present, especially lentinan and schizophyllan, which are clinically used as cancer therapies in some Asian countries. Thus, creation of these active triple-helix polysaccharides is beneficial to the research and development of sustainable "green" biopolymers in the fields of food and life sciences. Therefore, full fundamental research of triple-helix polysaccharides is essential to discover more applications for polysaccharides. In this Review, the recent research progress of chain conformations, bioactivities, and structure-function relationships of triple-helix β-glucans is summarized. The main contents include the characterization methods of the macromolecular conformation, proof of triple helices, bioactivities, and structure-function relationships. We believe that the governments, enterprises, universities, and institutes dealing with the survival and health of human beings can expect the development of natural bioproducts in the future. Hence, a deep understanding of β-glucans with triple-helix chain conformation is necessary for application of natural medicines and biologics for a sustainable world.

Shaping the Innate Immune Response by Dietary Glucans: Any Role in the Control of Cancer?

β-glucans represent a heterogeneous group of naturally occurring and biologically active polysaccharides found in many kinds of edible mushrooms, baker’s yeast, cereals and seaweeds, whose health-promoting effects have been known since ancient times. These compounds can be taken orally as food supplements or as part of daily diets, and are safe to use, nonimmunogenic and well tolerated. A main feature of β-glucans is their capacity to function as biological response modifiers, exerting regulatory effects on inflammation and shaping the effector functions of different innate and adaptive immunity cell populations. The potential to interfere with processes involved in the development or control of cancer makes β-glucans interesting candidates as adjuvants in antitumor therapies as well as in cancer prevention strategies. Here, the regulatory effects of dietary β-glucans on human innate immunity cells are reviewed and their potential role in cancer control is discussed.

Beneficial Effects of Oat Beta-Glucan Dietary Supplementation in Colitis Depend on its Molecular Weight

Background: Inflammatory bowel diseases are an important health problem. Therefore, the aim of the present study was to compare the impact of isolated oat beta-glucan fractions of low and high molecular weight, taken as dietary supplementation, on inflammatory markers in the colitis model. Methods: Two groups of Sprague–Dawley rats—control and with experimentally induced colitis—were subsequently divided into three subgroups and fed over 21 days feed supplemented with 1% of low (βGl) or high (βGh) molecular weight oat beta-glucan fraction or feed without supplementation. The level of colon inflammatory markers, cytokines, and their receptors’ genes expressions and immune cells numbers were measured by ELISA, RT-PCR, and by flow cytometry methods, respectively. Results: The results showed moderate inflammation affecting the colon mucosa and submucosa, with significant changes in the number of lymphocytes in the colon tissue, elevated cytokines and eicosanoid levels, as well as disruption of the main cytokine and chemokine cell signaling pathways in colitis rats. Beta-glucans supplementation caused a reverse in the percentage of lymphocytes with stronger effects of βGh and reduction of the levels of the inflammatory markers, and improvement of cytokine and chemokine signaling pathways with stronger effects of βGl supplementation. Conclusions: The results indicate the therapeutic effect of dietary oat beta-glucan supplementation in the colitis in evident relation to the molecular weight of polymer.

Yeast-Derived β-Glucan in Cancer: Novel Uses of a Traditional Therapeutic

An increased understanding of the complex mechanisms at play within the tumor microenvironment (TME) has emphasized the need for the development of strategies that target immune cells within the TME. Therapeutics that render the TME immune-reactive have a vast potential for establishing effective cancer interventions. One such intervention is β-glucan, a natural compound with immune-stimulatory and immunomodulatory potential that has long been considered an important anti-cancer therapeutic. β-glucan has the ability to modulate the TME both by bridging the innate and adaptive arms of the immune system and by modulating the phenotype of immune-suppressive cells to be immune-stimulatory. New roles for β-glucan in cancer therapy are also emerging through an evolving understanding that β-glucan is involved in a concept called trained immunity, where innate cells take on memory phenotypes. Additionally, the hollow structure of particulate β-glucan has recently been harnessed to utilize particulate β-glucan as a delivery vesicle. These new concepts, along with the emerging success of combinatorial approaches to cancer treatment involving β-glucan, suggest that β-glucan may play an essential role in future strategies to prevent and inhibit tumor growth. This review emphasizes the various characteristics of β-glucan, with an emphasis on fungal β-glucan, and highlights novel approaches of β-glucan in cancer therapy.