Oral administration of Lactobacillus acidophilus induces IL-12 production in spleen cell culture of BALB/c mice bearing transplanted breast tumour

Chemoprotective and immunomodulatory potential of Lactobacillus reuteri against cadmium chloride-induced breast cancer in mice

INTRODUCTION

The current study aimed to investigate the role of probiotic Lactobacillus reuteri for the treatment and prevention of breast cancer.

MATERIALS AND METHODS

Breast cancer was induced by using Cadmium Chloride (Cd) (2 mg/kg) in group II. Tamoxifen was administered to group III. Group IV was treated with Lactobacillus reuteri. Group V was treated with Cd for one month and divided into three subgroups including VA, VB, and VC which were treated with tamoxifen, Lactobacillus reuteri, and tamoxifen + Lactobacillus reuteri, respectively.

RESULTS

Significantly higher levels of TNF-α (40.9 ± 4.2 pg/mL), IL-6 (28.0 ± 1.5 pg/mL), IL-10 (60.2 ± 2.0 pg/mL), IFN-γ (60.2 ± 2.0 pg/mL), ALAT (167.2 ± 6.2 U/l), ASAT (451.6 ± 13.9 U/l), and MDA (553.8 ± 19.6 U/l) was observed in Cd group. In comparison, significantly lower levels of TNF-α (18.0 ± 1.1 pg/mL), IL-6 (9.4 ± 0.4 pg/mL), IL-10 (20.8 ± 1.1 pg/mL), IFN-γ (20.8 ± 1.1 pg/mL), ALAT (85.2 ± 3.6 U/l), ASAT (185 ± 6.9 U/l), and MDA (246.0 ± 7.5 U/l) were observed in group Cd + Tam + LR. Liver histopathology of the Cd group showed hemorrhage and ductal aberrations. However, mild inflammation and healthier branched ducts were observed in treatment groups. Furthermore, the renal control group showed normal glomerular tufts, chronic inflammation from the Cd group, and relatively healthier glomerulus with mild inflammation in treatment groups.

CONCLUSION

Hence, the preventive and anticancerous role of probiotic Lactobacillus reuteri is endorsed by the findings of the current study.

Lactic Acid Bacteria-Derived Postbiotics as Adjunctive Agents in Breast Cancer Treatment to Boost the Antineoplastic Effect of a Conventional Therapeutic Comprising Tamoxifen and a New Drug Candidate: An Aziridine-Hydrazide Hydrazone Derivative

Breast cancer is associated with high mortality and morbidity rates. As about 20-30% of patients exhibiting ER-positive phenotype are resistant to hormonal treatment with the standard drug tamoxifen, finding new therapies is a necessity. Postbiotics, metabolites, and macromolecules isolated from probiotic bacteria cultures have been proven to have sufficient bioactivity to exert prohealth and anticancer effects, making them viable adjunctive agents for the treatment of various neoplasms, including breast cancer. In the current study, postbiotics derived from L. plantarum and L. rhamnosus cultures were assessed on an in vitro breast cancer model as potential adjunctive agents to therapy utilizing tamoxifen and a candidate aziridine-hydrazide hydrazone derivative drug. Cell viability and cell death processes, including apoptosis, were analyzed for neoplastic MCF-7 cells treated with postbiotics and synthetic compounds. Cell cycle progression and proliferation were analyzed by PI-based flow cytometry and Ki-67 immunostaining. Postbiotics decreased viability and triggered apoptosis in MCF-7, modestly affecting the cell cycle and showing a lack of negative impact on normal cell viability. Moreover, they enhanced the cytotoxic effect of tamoxifen and the new candidate drug toward MCF-7, accelerating apoptosis and the inhibition of proliferation. This illustrates postbiotics' potential as natural adjunctive agents supporting anticancer therapy based on synthetic drugs.

Gut and local microbiota in patients with cancer: increasing evidence and potential clinical applications

In recent years, cancer research has highlighted the role of disrupted microbiota in carcinogenesis and cancer recurrence. However, microbiota may also interfere with drug metabolism, influencing the efficacy of cancer drugs, especially immunotherapy, and modulating the onset of adverse events. Intestinal micro-organisms can be altered by external factors, such as use of antibiotics, proton pump inhibitors treatment, lifestyle and the use of prebiotics or probiotics. The aim of our review is to provide a picture of the current evidence about preclinical and clinical data of the role of gut and local microbiota in malignancies and its potential clinical role in cancer treatments. Standardization of microbiota sequencing approaches and its modulating strategies within prospective clinical trials could be intriguing for two aims: first, to provide novel potential biomarkers both for early cancer detection and for therapeutic effectiveness; second, to propose personalized and "microbiota-tailored" treatment strategies.

Coadministration of doxorubicin with vitamin D3, Lactobacillus acidophilus, and Lactobacillus casei in the 4T1 mouse model of breast cancer: anticancer and enteroprotective effects

The use of doxorubicin (Dox) in the treatment of breast cancer negatively affects the intestines and other tissues. Many studies have proven that probiotics and vitamin D3 have antitumor and intestinal tissue-protecting properties. To achieve effectiveness and minimize side effects, the current study aims to administer Dox together with probiotics (Lactobacillus acidophilus and Lactobacillus casei) and vitamin D3. Forty-two female BALB/c inbred mice were divided into six groups: Group 1 (Control), Group 2 (Dox), Group 3 (Dox and probiotics), Group 4 (Dox and vitamin D3), Group 5 (Dox, probiotics, and vitamin D3), and Group 6 (probiotics and vitamin D3). The 4T1 mouse carcinoma cell line was injected into the mammary fat pad of each mouse. Gene expression was examined using quantitative real-time PCR. The treated groups (except group 6) showed significantly reduced tumor volume and weight compared to the control group (P < 0.05, P < 0.01). Probiotics/vitamin D3 with Dox reduced chemotherapy toxicity and a combination of supplements had a significant protective effect against Dox (P < 0.05, 0.01, 0.001). The treated groups (except 6) had significantly higher expression of Bax/Caspase 3 genes and lower expression of Bcl-2 genes than the control group (P < 0.05, 0.01). Coadministration of Dox with probiotics and vitamin D3 showed promising results in reducing tumor size, protecting intestinal tissue and influencing gene expression, suggesting a strategy to enhance the effectiveness of breast cancer treatment while reducing side effects.

Exploring the underlying correlation between microbiota, immune system, hormones, and inflammation with breast cancer and the role of probiotics, prebiotics and postbiotics

According to recent research, bacterial imbalance in the gut microbiota and breast tissue may be linked to breast cancer. It has been discovered that alterations in the makeup and function of different types of bacteria found in the breast and gut may contribute to growth and advancement of breast cancer in several ways. The main role of gut microbiota is to control the metabolism of steroid hormones, such as estrogen, which are important in raising the risk of breast cancer, especially in women going through menopause. On the other hand, because the microbiota can influence mucosal and systemic immune responses, they are linked to the mutual interactions between cancer cells and their local environment in the breast and the gut. In this regard, the current review thoroughly explains the mode of action of probiotics and microbiota to eradicate the malignancy. Furthermore, immunomodulation by microbiota and probiotics is described with pathways of their activity.

STAT4 Phosphorylation of T-helper Cells predicts surgical outcomes in Refractory Chronic Rhinosinusitis

Objective

Chronic rhinosinusitis (CRS) impacts an estimated 5% to 15% of people worldwide, incurring significant economic healthcare burden. There is a urgent need for the discovery of predictive biomarkers to improve treatment strategies and outcomes for CRS patients.

Study design

Cohort study of CRS patients and healthy controls using blood samples.

Setting

Out-patient clinics.

Methods

Whole blood samples were collected for flow cytometric analysis. Mechanistic studies involved the transfection of human primary T cells and Jurkat cells.

Results

Our analysis began with a 63-69 year-old female patient diagnosed with refractory CRS,. Despite undergoing multiple surgeries, she continually faced sinus infections. Whole exome sequencing pinpointed a heterozygous IL-12Rb1 mutation situated in the linker region adjacent to the cytokine binding domain. When subjected to IL-12 stimulation, the patient's CD4 T-cells exhibited diminished STAT4 phosphorylation. However, computer modeling or T-cell lines harboring the same IL-12 receptor mutation did not corroborate the hypothesis that IL-12Rb could be responsible for the reduced phosphorylation of STAT4 by IL-12 stimulation. Upon expanding our investigation to a broader CRS patient group using the pSTAT4 assay, we discerned a subset of refractory CRS patients with abnormally low STAT4 phosphorylation. The deficiency showed improvement both in-vitro and in-vivo after exposure to Latilactobacillus sakei (aka Lactobacillus sakei), an effect at least partially dependent on IL-12.

Conclusion

In refractory CRS patients, an identified STAT4 defect correlates with poor clinical outcomes after sinus surgery, which can be therapeutically targeted by Latilactobacillus sakei treatment. Prospective double-blind placebo-controlled trials are needed to validate our findings.

Comparison of the effects of probiotic strains (Lactobacillus gasseri, Lactiplantibacillus plantarum, Lactobacillus acidophilus, and Limosilactobacillus fermentum) isolated from human and food products on the immune response of CT26 tumor-bearing mice

This study aimed to compare the effects of the probiotic bacteria, L. gasseri (52b), L. plantarum (M11), L. acidophilus (AC2), and L. fermentum (19SH), isolated from human source and traditional food products on the modulation of the immune system and inflammatory response on BALB/c mouse model bearing CT26 tumor. Five groups of female inbred BALB/c mice were orally administered with the probiotics and their mixes (MIX, at a 1:1 ratio) at varying dosages (1.5 × 108 cfu/ml and 1.2 × 109 cfu/ml) before and after the injection of a subcutaneous CT26 tumor over the course of 38 days via gavage. Finally, their effects on the tumor apoptosis and the cytokine levels in spleen cell cultures were analyzed and compared. M11, MIX, and 52b groups had the greatest levels of interleukin-12 (IL-12) and interferon gamma (IFN-γ) production. The highest production level of granzyme B (GrB) was related to the MIX and 52b groups. Moreover, these groups showed the lowest production level of (IL-4) and transforming growth factor beta (TGF-β). Furthermore, the groups of MIX and 52b demonstrated the greatest amount of lymphocyte proliferation of spleen cells in response to the tumor antigen. The delayed-type hypersensitivity (DTH) response significantly increased in the groups of MIX and 52b compared with the control (p < 0.05). The findings demonstrated that the oral treatment of the human strain (52b) and the combination of these bacteria generated strong T helper type 1 (Th1) immune responses in the tumor tissue of the tumor-bearing mice, which led to the suppression of the tumor development.

Therapeutic and immunomodulatory role of probiotics in breast cancer: A mechanistic review

Breast cancer has become the most prevalent and noxious type of malignancy around the globe (Giaquinto et al., 2022). Multiple clinical strategies including chemotherapy, radiotherapy, and immunotherapy have been in practice to manage breast cancer. Besides the protective roles of conventional remedial approaches, and non-reversible and deteriorative impacts like healthy cell damage, organ failure, etc., the world scientific community is in a continuous struggle to find some alternative biocompatible and comparatively safe solutions. Among novel breast cancer management/treatment options, the role of probiotics has become immensely important. The current review encompasses the prevalence statistics of breast cancer across the globe concerning developed and undeveloped counties, intestinal microbiota linkage with breast cancer, and association of breast microbiome with breast carcinoma. Furthermore, this review also narrates the role of probiotics against breast cancer and their mode of action. In Vivo and In Vitro studies under breast cancer research regarding probiotics are mechanistically explained. The current review systematically explains the immunomodulatory role of probiotics to prevent breast cancer. Last, but not the least, current review concludes the use of probiotics in the treatment of breast cancer through various mechanisms and future recommendations for molecular basis studies.

Role of Gut Microbiota in Breast Cancer and Drug Resistance

Breast cancer is the most common malignancy in women worldwide. The cause of cancer is multifactorial. An early diagnosis and the appropriate treatment of cancer can improve the chances of survival. Recent studies have shown that breast cancer is influenced by the microbiota. Different microbial signatures have been identified in the breast microbiota, which have different patterns depending on the stage and biological subgroups. The human digestive system contains approximately 100 trillion bacteria. The gut microbiota is an emerging field of research that is associated with specific biological processes in many diseases, including cardiovascular disease, obesity, diabetes, brain disease, rheumatoid arthritis, and cancer. In this review article, we discuss the impact of the microbiota on breast cancer, with a primary focus on the gut microbiota’s regulation of the breast cancer microenvironment. Ultimately, updates on how immunotherapy can affect the breast cancer-based microbiome and further clinical trials on the breast and microbiome axis may be an important piece of the puzzle in better predicting breast cancer risk and prognosis.

The gut microbiota in breast cancer development and treatment: The good, the bad, and the useful!

Regardless of the global progress in early diagnosis and novel therapeutic regimens, breast carcinoma poses a devastating threat, and the advances are somewhat marred by high mortality rates. Breast cancer risk prediction models based on the known risk factors are extremely useful, but a large number of breast cancers develop in women with no/low known risk. The gut microbiome exerts a profound impact on the host health and physiology and has emerged as a pivotal frontier in breast cancer pathogenesis. Progress in metagenomic analysis has enabled the identification of specific changes in the host microbial signature. In this review, we discuss the microbial and metabolomic changes associated with breast cancer initiation and metastatic progression. We summarize the bidirectional impact of various breast cancer-related therapies on gut microbiota and vice-versa. Finally, we discuss the strategies to modulate the gut microbiota toward a more favorable state that confers anticancer effects.

Understanding and harnessing triple-negative breast cancer-related microbiota in oncology

Bacterial inhabitants of the body have the potential to play a role in various stages of cancer initiation, progression, and treatment. These bacteria may be distal to the primary tumour, such as gut microbiota, or local to the tissue, before or after tumour growth. Breast cancer is well studied in this context. Amongst breast cancer types, Triple Negative Breast Cancer (TNBC) is more aggressive, has fewer treatment options than receptor-positive breast cancers, has an overall worse prognosis and higher rates of reoccurrence. Thus, an in-depth understanding of the bacterial influence on TNBC progression and treatment is of high value. In this regard, the Gut Microbiota (GM) can be involved in various stages of tumour progression. It may suppress or promote carcinogenesis through the release of carcinogenic metabolites, sustenance of proinflammatory environments and/or the promotion of epigenetic changes in our genome. It can also mediate metastasis and reoccurrence through interactions with the immune system and has been recently shown to influence chemo-, radio-, and immune-therapies. Furthermore, bacteria have also been found to reside in normal and malignant breast tissue. Several studies have now described the breast and breast tumour microbiome, with the tumour microbiota of TNBC having the least taxonomic diversity among all breast cancer types. Here, specific conditions of the tumour microenvironment (TME) - low O2, leaky vasculature and immune suppression - are supportive of tumour selective bacterial growth. This innate bacterial ability could enable their use as delivery agents for various therapeutics or as diagnostics. This review aims to examine the current knowledge on bacterial relevance to TNBC and potential uses while examining some of the remaining unanswered questions regarding mechanisms underpinning observed effects.

Diet, Microbes, and Cancer Across the Tree of Life: a Systematic Review

PURPOSE OF REVIEW

Cancers are a leading cause of death in humans and for many other species. Diet has often been associated with cancers, and the microbiome is an essential mediator between diet and cancers. Here, we review the work on cancer and the microbiome across species to search for broad patterns of susceptibility associated with different microbial species.

RECENT FINDINGS

Some microbes, such as Helicobacter bacteria, papillomaviruses, and the carnivore-associated Fusobacteria, consistently induce tumorigenesis in humans and other species. Other microbes, such as the milk-associated Lactobacillus, consistently inhibit tumorigenesis in humans and other species. We systematically reviewed over a thousand published articles and identified links between diet, microbes, and cancers in several species of mammals, birds, and flies. Future work should examine a larger variety of host species to discover new model organisms for human preclinical trials, to better understand the observed variance in cancer prevalence across species, and to discover which microbes and diets are associated with cancers across species. Ultimately, this could help identify microbial and dietary interventions to diagnose, prevent, and treat cancers in humans as well as other animals.

Modulating Microbiota as a New Strategy for Breast Cancer Prevention and Treatment

Breast cancer (BC) is the most common cancer in women in the United States. There has been an increasing incidence and decreasing mortality rate of BC cases over the past several decades. Many risk factors are associated with BC, such as diet, aging, personal and family history, obesity, and some environmental factors. Recent studies have shown that healthy individuals and BC patients have different microbiota composition, indicating that microbiome is a new risk factor for BC. Gut and breast microbiota alterations are associated with BC prognosis. This review will evaluate altered microbiota populations in gut, breast tissue, and milk of BC patients, as well as mechanisms of interactions between microbiota modulation and BC. Probiotics and prebiotics are commercially available dietary supplements to alleviate side-effects of cancer therapies. They also shape the population of human gut microbiome. This review evaluates novel means of modulating microbiota by nutritional treatment with probiotics and prebiotics as emerging and promising strategies for prevention and treatment of BC. The mechanistic role of probiotic and prebiotics partially depend on alterations in estrogen metabolism, systematic immune regulation, and epigenetics regulation.

Gut microbiota: Role and Association with Tumorigenesis in Different Malignancies

The microbiota has been associated with different cancer and may vary from patient to patient. A specific microbial strain can alter the progression of cancer and therapeutic outcome in response to anti-cancer therapy. The variations in microbiota contributed due to the individual microbiome of the microorganism are responsible for diverse clinical outcomes. The expansion of microbiota subpopulation during dysbiosis can lead to toxin production, inducing inflammation and cancer. The microbiota can be a dual-edged sword because it can be tumor-suppressive or oncogenic in the case of the gut. The transition of cancer cells from early to late-stage also impacts the composition of the microbiota, and this alteration could change the behavior of cancer. Multi-omics platforms derived data from an individual's multi-dimensional data (DNA, mRNA, microRNA, protein, metabolite, microbiota, and microbiome), i.e., individualome, to exploit it for personalized tailored treatment for different cancers in a precise manner. A number of studies suggest the importance of microbiota and its add-in suitability to existing treatment options for different malignancies. Furthermore, in vitro, and in vivo studies and cancer clinical trials suggest that probiotics have driven modulation of gut microbiota and other sites discourage the aggressive behavior and progression of different cancers.

The crosstalk of the human microbiome in breast and colon cancer: A metabolomics analysis

The human microbiome's role in colon and breast cancer is described in this review. Understanding how the human microbiome and metabolomics interact with breast and colon cancer is the chief area of this study. First, the role of the gut and distal microbiome in breast and colon cancer is investigated, and the direct relationship between microbial dysbiosis and breast and colon cancer is highlighted. This work also focuses on the many metabolomic techniques used to locate prospective biomarkers, make an accurate diagnosis, and research new therapeutic targets for cancer treatment. This review clarifies the influence of anti-tumor medications on the microbiota and the proactive measures that can be taken to treat cancer using a variety of therapies, including radiotherapy, chemotherapy, next-generation biotherapeutics, gene-based therapy, integrated omics technology, and machine learning.

Comparison of probiotic Lactobacillus strains isolated from dairy and Iranian traditional food products with those from human source on intestinal microbiota using BALB/C mice model

This study compares the probiotic Lactobacillus strains isolated from dairy and Iranian traditional food products with those from human sources on intestinal microbiota using BALB/C mice model. First, Lactiplantibacillus plantarum (M11), Limosilactobacillus fermentum (19SH), Lactobacillus acidophilus (AC2), and Lactobacillus gasseri (52b) strains, isolated from either Iranian traditionally fermented products or human (healthy woman vaginal secretions), identified with molecular methods and selected based on the surface hydrophobicity, auto- and co-aggregation, were investigated for their probiotic properties and compared with their standard probiotic strains in vitro. The native strains and their mixtures (MIX) were then orally fed to five groups of female inbred BALB/C mice over the course of 38 days by gavage at 0.5 and 4 McFarland, respectively, equal to 1.5 × 10⁸ and 1 × 10⁹ cfu/ml. Feeding paused for 6 days to test the bacteria's adhesion in vivo. According to the findings, the probiotic Lactobacillus strain isolated from human source (52b) exhibited the best in vitro and in vivo adhesion ability. Probiotic Lactobacillus strains isolated from Iranian traditional food products (19SH and AC2) had the most co-aggregation with Listeria monocytogenes (ATTC 7644), Salmonella enterica subsp. enterica (ATCC 13,076), and Escherichia coli (NCTC 12,900 O157:H7) in vitro. These strains produced the most profound decreasing effect on the mice intestinal microbiota and pathogens in vivo. The difference in the strains and their probiotic potential is related to the sources from which they are isolated as well as their cell walls. The results suggest that (19SH and 52b strains) are the best candidates to investigate the cell wall and its effect on the host immune system.

A review on anticancer, antibacterial and photo catalytic activity of various nanoparticles synthesized by probiotics

Probiotics are beneficial bacteria that have a significant effect on host health and they are widely used in preventing and treating diseases. Nowadays probiotics are present in food, drug and several commercial complement products. In recent years the use of probiotics in the nanotechnology area, especially in nanoparticle synthesis, has significantly been increased. In this review, after some introduction about probiotic and their advantages, all the nanoparticles produced by probiotics are reviewed and discussed. Furthermore, biosynthetic mechanisms of nanoparticles and its applications in cancer therapy, antibacterial and photo catalytic activities, are also discussed.

The Relationship Between Microbial Community and Breast Cancer

Breast cancer (BC) is the most common cancer in women and the leading cause of cancer-related deaths in women worldwide. Recent research studies have shown that the intestinal flora is related to the occurrence and progression of BC. Notably, some evidence identifies a unique microbial community in breast tissue, a site previously thought to be sterile. In addition, breast tumors have their own specific microbial community, distinct from normal mammary gland tissue, and all of them may result from intestinal flora. Some microbial community in breast tissue may lead to the occurrence and development of BC. This review focuses on the relationship between the microbial community and breast cancer, which will lay a solid theoretical foundation for further understanding the local microenvironment of BC and developing effective targeted therapeutic drugs.

Assessment of probiotic efficacy and anticancer activities of Lactiplantibacillus plantarum ESSG1 (MZ683194.1) and Lactiplantibacillus pentosus ESSG2 (MZ683195.1) isolated from dairy products

Resistance to antibiotics is on the rise, and its indiscriminate usage has resulted in human and animal management constraints. In the research for an innovative treatment to diminish antimicrobial resistance, lactic acid bacteria (LAB) throw light on diminishing this problem in public health. As a result, this paper looked at the efficacy of LAB isolates and their active metabolites to combat pathogens, reduce antibiotic use in clinical settings, and explore the anticancer potential of 8 strains of LAB isolated from dairy products. Antifungal and antibacterial potential of LAB isolates against selected crop pathogenic fungi and food pathogenic bacteria had been estimated. Results revealed that all isolates exert antioxidant efficacy relating to DPPH, NO scavenging ability, reducing power, superoxide anion, hydroxyl radical, and anti-lipid peroxidation potential. Additionally, 12B isolate exert the highest anticancer upshot with IC₅₀ values of 43.98 ± 0.4; 36.7 ± 0.6, 43.1 ± 0.8, and 35.1 ± 0.3 μg/ml, versus Caco-2, MCF-7, HepG-2, and PC3 cell lines respectively, whereas 13B isolate significantly had the highest selectivity index between peripheral blood mononuclear cells (PBMCs) and the tested human cancer cell lines compared to 5-fluorouracil. 13B was the most apoptosis-dependent death inducer for all human cancer cell lines besides exerting the lowest percentage of apoptosis against PBMCs suggesting its safety against PBMCs. The most promising strains 12B and 13B were identified by 16S rRNA sequencing as Lactiplantibacillus plantarum ESSG1 (MZ683194.1) and Lactiplantibacillus pentosus ESSG2 (MZ683195.1). LAB and their extracts are superb substitutive, safe, and efficient antimicrobial, antioxidant, and antitumor curative agents.

New Developments and Opportunities of Microbiota in Treating Breast Cancers

Despite the prevalence of breast cancer (BC), over half of BC cases are unrelated to known risk factors, which highlights the importance of uncovering more cancer-related factors. Currently, the microbiota has been proven to be a potent modulator of the tumor environment in BC, which regulates the immune balance in tumor-related networks. Through a large amount of data accumulation, the microbiota has shown many possibilities to reveal more insights into the development or control of BC. To expand the potential benefits of patients with BC, this study discusses the distribution profile and the effect mechanism of BC-related microbiota on tumors and further discusses its impact on different tumor therapies. Finally, we summarize the possibility of targeting microbiological therapies to improve BC treatment or in combination with other therapies.

Investigation of the supportive therapy potential of propolis extract and Lactobacillus acidophilus LA-5 milk combination against breast cancer in mice

Immunotherapy has been applied in cancer treatments for many years as an alternative treatment method to radiotherapy, chemotherapy. It is well known that immunotherapy could suppress tumor formation by modulating the immune system of the host. The aim of the study is to investigate supportive therapy potential of acidophilus milk (AS) and propolis extract (PE) in the mouse xenograft breast cancer model. For this purpose, firstly cytotoxic effect of PE was determined by MTT assay against 4 T1 mouse breast cancer cells. Apoptotic effect of PE analyzed by flow cytometry. The antibacterial activity of PE was determined by the 96-well microplate broth-dilution method on Lactobacillus acidophilus LA-5. Then, Balb/c mice were injected subcutaneously with 4 T1 cells (2x10⁵ cells/mouse) and also mice were given daily oral gavage with PE (66 mg/kg/day) and/or acidophilus milk (10⁸ CFU/mL/mouse/day) for 14 days. The Balb/c mice were weighed throughout the study, and the tumor sizes were measured by caliper at the 14th day. The proliferation of splenocytes which collected spleen from mice was measured by MTT. CD8 + T cell response was analyzed by flow cytometry and results were evaluated in comparison with control and tumor control groups. The IC₅₀ value for PE on 4 T1 cells was determined as 129.25 ± 1.90 µg/mL. The apoptotic effect of PE at IC₅₀ concentration was determined as 3.3% of cells to late-apoptosis, 4.3% of cells to pro-apoptosis and 2.5% of cells to necrosis. The MIC and MBC values for PE on L. acidophilus LA-5 were 5000 ppm. The treatment of PE, AS and the combination of PE and AS were inhibited the tumor volumes by 59.16%, 28.29% and 63.39%, respectively. Acidophilus milk and PE combination significantly enhanced the ConA-, LPS- and PHA-induced splenocyte proliferation (P < 0.05). The acidophilus milk and PE combination were also found to stimulate IFN- γ production. In conclusion, the best anti-tumor effect was obtained by the combination of acidophilus milk and propolis.

A New Paradigm in the Relationship between Melatonin and Breast Cancer: Gut Microbiota Identified as a Potential Regulatory Agent

In this review we summarize a possible connection between gut microbiota, melatonin production, and breast cancer. An imbalance in gut bacterial population composition (dysbiosis), or changes in the production of melatonin (circadian disruption) alters estrogen levels. On the one hand, this may be due to the bacterial composition of estrobolome, since bacteria with β-glucuronidase activity favour estrogens in a deconjugated state, which may ultimately lead to pathologies, including breast cancer. On the other hand, it has been shown that these changes in intestinal microbiota stimulate the kynurenine pathway, moving tryptophan away from the melatonergic pathway, thereby reducing circulating melatonin levels. Due to the fact that melatonin has antiestrogenic properties, it affects active and inactive estrogen levels. These changes increase the risk of developing breast cancer. Additionally, melatonin stimulates the differentiation of preadipocytes into adipocytes, which have low estrogen levels due to the fact that adipocytes do not express aromatase. Consequently, melatonin also reduces the risk of breast cancer. However, more studies are needed to determine the relationship between microbiota, melatonin, and breast cancer, in addition to clinical trials to confirm the sensitizing effects of melatonin to chemotherapy and radiotherapy, and its ability to ameliorate or prevent the side effects of these therapies.

Probiotics in microbiome ecological balance providing a therapeutic window against cancer

The gut microbiota composition and dietary factors in our food along with the use of prebiotics and probiotics play an important role in the maintenance of human health. A well-balanced gut microbial population is necessary for the host and the microbiota to coexist in a mutually beneficial relationship maintaining homeostasis. Considering the potential of modern technological tools, it is possible nowadays to engineer prebiotic bacteria having a positive influence on the microbiome on one hand while on the other one may have the ease to get rid of the pathogenic proinflammatory microbes or elements causing dysbiosis. Past studies have seen that in cancer there is a loss of inter-microbial relationship cum interactions within microbiota members, the metabolic products produced by them and the host immune system in a microbial ecosystem, leading to dysbiosis. Current review highlights the importance of probiotics in the management of cancer by bringing together majority of the studies together at a single platform and moreover, stresses upon the need to maintain eubiosis in order to evade and inhibit the progression of cancer. Continuous expansion in knowledge about probiotics, their effect on various cancers and the underlying mechanism of action has raised the global scientific interest towards their possible use against different cancers. Furthermore, the article emphasizes upon the need to explore newer therapeutic targets comprising of the microbiome which could further pave the way to the concept of personalized medicines for various kinds of malignancies so as to derive maximum benefits of a treatment modality and to preserve the microbial homeostasis.

Effect of probiotics and gut microbiota on anti-cancer drugs: Mechanistic perspectives

Bacteria present in probiotics, particularly the common Lactobacillus and Bifidobacterium microbes, have been found to induce anti-cancer action by enhancing cancer cell apoptosis and protecting against oxidative stress. Probiotics supplements also decrease the cancer-producing microorganism Fusobacterium. Studies have demonstrated that gut microbiota modifies the effect of chemo/radiation therapy. Gut microbes not only enhance the action of chemotherapy drugs but also reduce the side effects of these medications. Additionally, gut microbes reduce immunotherapy toxicity, in particular, the presence of Bacteroidetes or Bifidobacterium decreases the development of colitis by ipilimumab therapy. Probiotics supplements containing Bifidobacterium also reduce chemotherapy-induced mucositis and radiation-induced diarrhea. This review focused on elucidating the mechanism behind the anti-cancer action of Bifidobacterium species. Available studies have revealed Bifidobacterium species decrease cancer cell proliferation via the inhibition of growth factor signaling as well as inducing mitochondrial-mediated apoptosis. Moreover, Bifidobacterium species reduce the adverse effects of chemo/immuno/radiation therapy by inhibiting proinflammatory cytokines. Further clinical studies are needed to identify the powerful and suitable Bifidobacterium strain for the development of adjuvant therapy to support chemo/immuno/radiation therapy.

The Gut Microbiota: A Potential Gateway to Improved Health Outcomes in Breast Cancer Treatment and Survivorship

Breast cancer is the most frequently diagnosed cancer in women worldwide. The disease and its treatments exert profound effects on an individual's physical and mental health. There are many factors that impact an individual's risk of developing breast cancer, their response to treatments, and their risk of recurrence. The community of microorganisms inhabiting the gastrointestinal tract, the gut microbiota, affects human health through metabolic, neural, and endocrine signaling, and immune activity. It is through these mechanisms that the gut microbiota appears to influence breast cancer risk, response to treatment, and recurrence. A disrupted gut microbiota or state of 'dysbiosis' can contribute to a biological environment associated with higher risk for cancer development as well as contribute to negative treatment side-effects. Many cancer treatments have been shown to shift the gut microbiota toward dysbiosis; however, the microbiota can also be positively manipulated through diet, prebiotic and probiotic supplementation, and exercise. The objective of this review is to provide an overview of the current understanding of the relationship between the gut microbiota and breast cancer and to highlight potential strategies for modulation of the gut microbiota that could lead to improved clinical outcomes and overall health in this population.

Breast and Gut Microbiota Action Mechanisms in Breast Cancer Pathogenesis and Treatment

In breast cancer (BC) the employment of sequencing technologies for metagenomic analyses has allowed not only the description of the overall metagenomic landscape but also the specific microbial changes and their functional implications. Most of the available data suggest that BC is related to bacterial dysbiosis in both the gut microenvironment and breast tissue. It is hypothesized that changes in the composition and functions of several breast and gut bacterial taxa may contribute to BC development and progression through several pathways. One of the most prominent roles of gut microbiota is the regulation of steroid-hormone metabolism, such as estrogens, a component playing an important role as risk factor in BC development, especially in postmenopausal women. On the other hand, breast and gut resident microbiota are the link in the reciprocal interactions between cancer cells and their local environment, since microbiota are capable of modulating mucosal and systemic immune responses. Several in vivo and in vitro studies show remarkable evidence that diet, probiotics and prebiotics could exert important anticarcinogenic effects in BC. Moreover, gut microbiota have an important role in the metabolism of chemotherapeutic drugs and in the activity of immunogenic chemotherapies since they are a potential dominant mediator in the response to cancer therapy. Then, the microbiome impact in BC is multi-factorial, and the gut and breast tissue bacteria population could be important in regulating the local immune system, in tumor formation and progression and in therapy response and/or resistance.

Significance of human microbiome in breast cancer: Tale of an invisible and an invincible

The human microbiome is a mysterious treasure of the body playing endless important roles in the well-being of the host metabolism, digestion, and immunity. On the other hand, it actively participates in the development of a variety of pathological conditions including cancer. With the Human Microbiome Project initiative, metagenomics, and next-generation sequencing technologies in place, the last decade has witnessed immense explorations and investigations on the enigmatic association of breast cancer with the human microbiome. However, the connection between the human microbiome and breast cancer remains to be explored in greater detail. In fact, there are several emerging questions such as whether the host microbiota contributes to disease initiation, or is it a consequence of the disease is an irrevocably important question that demands a valid answer. Since the microbiome is an extremely complex community, gaps still remain on how this vital microbial organ plays a role in orchestrating breast cancer development. Nevertheless, undeniable evidence from studies has pinpointed the presence of specific microbial elements of the breast and gut to play a role in governing breast cancer. It is still unclear if an alteration in microbiome/dysbiosis leads to breast cancer or is it vice versa. Though specific microbial signatures have been detected to be associated with various breast cancer subtypes, the structure and composition of a core "healthy" microbiome is yet to be established. Probiotics seem to be a promising antidote for targeted prevention and treatment of breast cancer. Interestingly, these microbial communities can serve as potential biomarkers for prognosis, diagnosis, and treatment of breast cancer, thereby leading to the rise of a completely new era of personalized medicine. This review is a humble attempt to summarize the research findings on the human microbiome and its relation to breast cancer.

Emerging role of microbiota in immunomodulation and cancer immunotherapy

Gut microbiota is emerging as a key modulator of the immune system. Alteration of gut microbiota impacts functioning of the immune system and pathophysiology of several diseases, including cancer. Growing evidence indicates that gut microbiota is not only involved in carcinogenesis but also has an impact on the efficacy and toxicity of cancer therapy. Recently, several pre-clinical and clinical studies across diverse cancer types reported the influence of gut microbiota on the host immune response to immunotherapy. Advancement in our understanding of the mechanism behind microbiota-mediated modulation of immune response is paramount for their utilization as cancer therapeutics. These microbial therapies in combination with conventional immunotherapeutic methods have the potential to transform the pre-existing treatment strategies to personalized cancer therapy. In this review, we have summarized the current status of research in the field and discussed the role of microbiota as an immune system modulator in context of cancer and their impact on immunotherapy.

Microbiota Manipulation by Probiotics Administration as Emerging Tool in Cancer Prevention and Therapy

A growing body of literature indicates that microbiota plays a significant role in the development and curability of cancer, essentially due to the microbial ability to modulate immune and inflammatory responses to cancer and therapeutic treatments. Probiotics consumption, either in the form of food or supplements, is an easy and feasible way to manipulate microbiota composition and a number of recent researches have shown that it may represent a valid approach to prevent cancer onset and progression, to improve the clinical efficacy of the current anticancer treatments, and to mitigate the harmful adverse events of chemo- and radiotherapy, which often lead to scale drug doses, to delay or interrupt treatments. In this review, we gather the main in vivo studies on the current topic, focusing on the beneficial effects and underlying mechanisms provided by bacterial and yeast probiotics and their combination, in the setting of various types of cancers and different therapeutic protocols. These findings will likely open the way to consider, in future, regular probiotics intake as an adjuvant strategy in cancer prevention and management.

Microbiome and Breast Cancer: New Role for an Ancient Population

There are many risk factors associated with breast cancer (BC) such as the familial history of BC, using hormone replacement therapy, obesity, personal habits, and other clinical factors; however, not all BC cases are attributed to these risk factors. Recent researches show a correlation between patient microbiome and BC suggested as a new risk factor. The present review article aimed at evaluating the role of the microbiome as a risk factor in the occurrence of BC, investigating the proposed mechanisms of interaction between the microbiome and human genes involved in BC, and assessing the impact of the altered composition of breast, gut, and milk microbiome in the physiological status of normal breast as well as cancerous or non-cancerous breast lesions. The study also evaluated the growing evidence that these altered populations may hinder chemotherapeutic treatment. The role of microbiome in the development and maintenance of inflammation, estrogen metabolism, and epigenetic alterations was properly investigated. Finally, clinical and therapeutic applications of the microbiome- e.g., probiotics, microbiome genome modulation, and engineered microbiome enzymes in the management of BC were reviewed.

Potential effect of probiotics in the treatment of breast cancer

Breast cancer is one of the most important causes of cancerrelated morbidity and mortality in the world. Probiotics, as functional food, have the potential to act against breast cancer, as evidenced by cell-based and animal model experiments. Probiotic may be useful in prevention or treatment of breast cancer by modulating the gastrointestinal bacteria and the systemic immune system. However, large-scale clinical trials and intensive research are mandatory to confirm the in vitro and in vivo results and exploring the probiotics-related metabolic, immune, and molecular mechanisms in breast cancer. This current review summarizes the available data related to probiotics and their potential role in the treatment of breast cancer.

Emerging Roles of Probiotics in Prevention and Treatment of Breast Cancer: A Comprehensive Review of Their Therapeutic Potential

Breast cancer is the most common cancer among women. Need for novel preventive and curative approaches with more safety than the present one seems inevitable. This review is devoted to potentially favorable role of probiotics in prevention and treatment of breast cancer as well as their alleviating role regarding chemotherapy-induced side effects. Literature was searched for human, animal, and in vitro studies about the role of probiotics in breast cancer. In vitro studies showed that probiotic intervention induces cancer cells apoptosis and inhibits their proliferation. In animal models, treatment with probiotics inhibited tumor growth and reduced tumor size; also, the immunomodulatory, antiangiogenesis and antimetastatic activities of probiotics were illustrated. Human studies showed that intake of Lactobacillus casei shirota reduced the breast cancer incidence and consumption of fermented milk products and yogurt was inversely associated with breast cancer incidence; however, no study regarding the curative role of probiotics in breast cancer is available. Studies on the effect of probiotics on chemotherapy-induced side effects in breast cancer were contradictory but showed potential for more investigation. Probiotics seem to have a potential role in both prevention and treatment of breast cancer. However, more clinical studies are needed to elucidate their efficacy and safety.

Preparation, characterization and in-vivo evaluation of microemulsions containing tamoxifen citrate anti-cancer drug

The aim of this study was to prepare and characterize a new nanocarrier for oral delivery of tamoxifen citrate (TMC) as a lipophilic oral administrated drug. This drug has low oral bioavailability due to its low aqueous solubility. To enhance the solubility of this drug, the microemulsion system was applied in form of oil-in-water. Sesame oil and Tween 80 were used as drug solvent oil and surfactant, respectively. Two different formulations were prepared for this purpose. The first formulation contained edible glycerin as co-surfactant and the second formulation contained Span 80 as a mixed surfactant. The results of characterization showed that the mean droplet size of drug-free samples was in the range of 16.64-64.62nm with a PDI value of <0.5. In a period of 6months after the preparation of samples, no phase sedimentation was observed, which confirmed the high stability of samples. TMC with a mass ratio of 1% was loaded in the selected samples. No significant size enlargement and drug precipitation were observed 6months after drug loading. In addition, the drug release profile at experimental environments in buffers with pH=7.4 and 5.5 showed that in the first 24h, 85.79 and 100% of the drug were released through the first formulation and 76.63 and 66.42% through the second formulation, respectively. The in-vivo results in BALB/c female mice showed that taking microemulsion form of drug caused a significant reduction in the growth rate of cancerous tumor and weight loss of the mice compared to the consumption of commercial drug tablets. The results confirmed that the new formulation of TMC could be useful for breast cancer treatment.

The Potential Role of Probiotics in Cancer Prevention and Treatment

The human gut microbiota has a significant effect on many aspects of human physiology such as metabolism, nutrient absorption, and immune function. Imbalance of the microbiota has been implicated in many disorders including inflammatory bowel disease, obesity, asthma, psychiatric illnesses, and cancers. As a kind of functional foods, probiotics have been shown to play a protective role against cancer development in animal models. Clinical application of probiotics indicated that some probiotic strains could diminish the incidence of postoperative inflammation in cancer patients. Chemotherapy or radiotherapy-related diarrhea was relieved in patients who were administered oral probiotics. The present review summarizes the up-to-date studies on probiotic effects and the underlying mechanisms related to cancer. At present, it is commonly accepted that most commercial probiotic products are generally safe and can improve the health of the host. By modulating intestinal microbiota and immune response, some strains of probiotics can be used as an adjuvant for cancer prevention or/and treatment.

Evolving Roles of Probiotics in Cancer Prophylaxis and Therapy

In nutraceutical science, the ingestible live microbes 'probiotics' are regarded for their ability to confer multiplicity of health benefits on the consumers. Wide spectrum impact of these friendly microbes on the host health has been proved very frequently. They have been confirmed to boost immunity, aid in digestion, eliminate pathogens, curb inflammatory bowel diseases, moderate side effects of antibiotic therapy, lower cholesterol and blood glycemic index and produce vitamins. This review, however, focuses on the incipient, but promising area of probiotic diet-based prevention and remedy of cancer. Researchers are in universal agreement with the critical role of probiotics in getting rid of mutagens, delaying the onset of tumors, alleviating the side effects, pepping up chemotherapy, easing the postoperative complications, foiling remission and lifting the spirit of survivors. The key findings in the emerging roles of probiotics in onco-care have been summarized; the biological pathways discussed and anticipated developments in coming times are presented.

Th1 Immune Response Induction by Biogenic Selenium Nanoparticles in Mice with Breast Cancer: Preliminary Vaccine Model

BACKGROUND

Tumor associated antigens can be viably used to enhance host immune response.

OBJECTIVES

The immunomodulatory effect of biogenic selenium nanoparticles (SeNPs) was compared between treated and untreated mice with crude antigens of 4T1 cells.

MATERIALS AND METHODS

Female inbred BALB/c mice (60) were injected by cancinogenic 4T1 cells causing breast cancer. After 10 days, all tumor bearing mice were divided into 4 groups. Group 1 was daily provided oral PBS and injected by the same buffer after tumor induction and was considered as control. Group 2 received only 100 μg/day SeNPs as an oral supplement for 30 days. Group 3 was only injected with 4T1 cells crude antigens with nil supplementation of SeNPs. Group 4 animals were supplemented 100 μg/day SeNPs for 30 days and simultaneously injected with crude antigens of 4T1 cells. All antigens or PBS injections were introduced at 7, 14 and 28 days following tumor induction. Oral PBS and SeNPs supplementation initiated from the first day of tumor induction and continued up to 30 days. During tumor growth, animal weights and survival rates were monitored and at the end of the study the concentrations of different cytokines and DTH responses were measured.

RESULTS

Data clearly showed that the levels of cellular immunomodulatory components (granzyme B, IL-12, IFN-γ, and IL-2) significantly increased (P < 0.05) in mice treated with both SeNPs and crude antigens of 4T1 cells in comparison to the other groups. In contrast, the levels of TGF-β in these mice decreased.

CONCLUSIONS

Although SeNPs showed a noticeable boosting effect for the immune response in mice bearing tumor exposed to crude antigens of 4T1 cells, further complementary studies seem to be inevitable.

Th1 Cytokine Production Induced by Lactobacillus acidophilus in BALB/c Mice Bearing Transplanted Breast Tumor

Background:

The immunomodulative effects of Lactic Acid Bacteria as probiotics have been already demonstrated.

Objectives:

The current study aimed to evaluate the effect of oral administration of Lactobacillus acidophilus on the immune responses and patterns of cytokine production in the BALB/c mice bearing breast cancer.

Materials and Methods:

The current study used thirty inbred BALB/c mice, six- to eight-week-old; they were divided into two groups of 15 each. One group was used as control in each assay. The L. acidophilus (ATCC4356) used in the study was inoculated in MRS broth and cultivated overnight at 37°C under anaerobic conditions, then collected by centrifugation, and re-suspended in Phosphate-buffered Saline (PBS) media. After preparation of the proper amount of the suspension, it was orally administered to the mice via gavage and the control mice received an equal volume of PBS in the same manner.

Results:

The results showed that oral administration of L. acidophilus as a potent immunostimulator agent could motivate the proliferation of immune cells. Moreover, it could increase the production of IFN-γ and decrease the production of IL-4, known as Th2 cytokines, in the spleen cell culture. The results showed that the survival time of the L. acidophilus administered mice significantly increased in comparison to that of the control mice.

Conclusions:

The current study findings suggested that L. acidophilus can promote immune responses with Th1 bias and may increase the antitumor response. Further, the consumption of this probiotic strain may help to manage the immune response in tumor condition, but more studies are needed to investigate the other mechanisms of this effect.

Selenium nanoparticle-enriched Lactobacillus brevis causes more efficient immune responses in vivo and reduces the liver metastasis in metastatic form of mouse breast cancer

BACKGROUND AND THE PURPOSE OF THE STUDY

Selenium enriched Lactobacillus has been reported as an immunostimulatory agent which can be used to increase the life span of cancer bearing animals. Lactic acid bacteria can reduce selenium ions to elemental selenium nanoparticles (SeNPs) and deposit them in intracellular spaces. In this strategy two known immunostimulators, lactic acid bacteria (LAB) and SeNPs, are concomitantly administered for enhancing of immune responses in cancer bearing mice.

METHODS

Forty five female inbred BALB/c mice were divided into three groups of tests and control, each containing 15 mice. Test mice were orally administered with SeNP-enriched Lactobacillus brevis or Lactobacillus brevis alone for 3 weeks before tumor induction. After that the administration was followed in three cycles of seven days on/three days off. Control group received phosphate buffer saline (PBS) at same condition. During the study the tumor growth was monitored using caliper method. At the end of study the spleen cell culture was carried out for both NK cytotoxicity assay and cytokines measurement. Delayed type hypersensitivity (DTH) responses were also assayed after 72h of tumor antigen recall. Serum lactate dehydrogenase (LDH) and alkaline phosphatase (ALP) levels were measured, the livers of mice were removed and prepared for histopathological analysis.

RESULTS

High level of IFN-γ and IL-17 besides the significant raised in NK cytotoxicity and DTH responses were observed in SeNP-enriched L. brevis administered mice and the extended life span and decrease in the tumor metastasis to liver were also recorded in this group compared to the control mice or L.brevis alone administered mice.

CONCLUSION

Our results suggested that the better prognosis could be achieved by oral administration of SeNP-enriched L. brevis in highly metastatic breast cancer mice model.

Lactobacillus acidophilus could modulate the immune response against breast cancer in murine model

Cancer immune-therapy is an interesting avenue of studying the effects of deviating immune system responses to achieve the desired result. Lactobacilli are inhabitants of the GI tract which have shown beneficial health effects on various ailments including malignancies. Their mechanisms of action comprise a very intense area of research. In this study we evaluated the immunomodulatory effects of Lactobacillus acidophilus in in vivo model of breast cancer. Lactobacillus acidophilus (L.a) was isolated from traditional home-made yogurt and also from neonatal stool by aerobic overnight culture at 37°C in MRS broth. Delayed Type Hypersensitivity (DTH) assay was performed to find the best immunostimulant dose. 4T1 tumour bearing mice were treated with 2 × 10(8) cfu of isolated L. acidophilus and 20 mg/kg Cyclophosphamide for 15 consecutive days. Tumour volume was measured using a digital vernier calliper. Lymphocyte proliferation was done using MTT proliferation assay. Production of IFNγ, IL-4 and TGF-β from cultured Splenocytes was assessed in the presence of purified tumour antigen. According to results administration of L.a induced a significant decrease in tumour growth pattern (P value = 0.00). Significant alterations in splenocyte production of IFN-γ, IL-4 and TGf-β (P values < 0.05) and also lymphocyte proliferation in L.a treated animals was evident (P value < 0.05). This study indicated that oral administration of L.a is able to alter the cytokine production in tumour bearing mice into a Th1 protective pattern, favourable to anti tumour immunity. Reduced tumour growth rate and increased lymphocyte proliferation are also thus supportive. Further studies are required to elucidate the exact mechanism by which local actions of probiotics affect the systemic immune responses against transformed cells.

High dose and low dose Lactobacillus acidophilus exerted differential immune modulating effects on T cell immune responses induced by an oral human rotavirus vaccine in gnotobiotic pigs

BACKGROUND

Strain-specific effects of probiotics in pro- or anti-inflammatory immune responses have been well recognized. Several proinflammatory Lactobacillus strains have been shown to act as adjuvants to enhance the immunogenicity of vaccines. However, dose effects of probiotics in modulating immune responses are not clearly understood. This study examined the dose effects of Lactobacillus acidophilus (LA) NCFM strain on T cell immune responses to rotavirus vaccination in a gnotobiotic (Gn) pig model.

METHODS

Frequencies of IFN-γ producing CD4+ and CD8+ T cell and IL-10 and TGF-β producing CD4+CD25+ and CD4+CD25- regulatory T (Treg) cell responses were determined in the intestinal and systemic lymphoid tissues of Gn pigs vaccinated with an oral human rotavirus vaccine in conjunction with low dose (5 feedings; up to 10(6) colony forming units [CFU]/dose) or high dose (14 feedings; up to 10(9)CFU/dose) or without LA feeding.

RESULTS

Low dose LA significantly promoted IFN-γ producing T cell responses and down-regulated Treg cell responses and their TGF-β and IL-10 productions in all the tissues compared to the high dose LA and control groups. To the contrary, high dose LA increased the frequencies of Treg cells in most of the tissues compared to the control groups. The dose effects of LA on IFN-γ producing T cell and CD4+CD25- Treg cell immune responses were similar in the intestinal and systemic lymphoid tissues and were independent from the vaccination.

CONCLUSION

Thus the same probiotic strain in different doses can either promote or suppress IFN-γ producing T cell or Treg cell immune responses. These findings have significant implications in the use of probiotic lactobacilli as immunostimulatory versus immunoregulatory agents. Probiotics can be ineffective or even detrimental if not used at the optimal dosage for the appropriate purposes.