Differential induction of apoptosis in human colonic carcinoma cells (Caco-2) by Atopobium, and commensal, probiotic and enteropathogenic bacteria: mediation by the mitochondrial pathway

Identification of consensus head and neck cancer-associated microbiota signatures: a systematic review and meta-analysis of 16S rRNA and The Cancer Microbiome Atlas datasets

Introduction. Multiple reports have attempted to describe the tumour microbiota in head and neck cancer (HNSC).Gap statement. However, these have failed to produce a consistent microbiota signature, which may undermine understanding the importance of bacterial-mediated effects in HNSC.Aim. The aim of this study is to consolidate these datasets and identify a consensus microbiota signature in HNSC.Methodology. We analysed 12 published HNSC 16S rRNA microbial datasets collected from cancer, cancer-adjacent and non-cancer tissues to generate a consensus microbiota signature. These signatures were then validated using The Cancer Microbiome Atlas (TCMA) database and correlated with the tumour microenvironment phenotypes and patient's clinical outcome.Results. We identified a consensus microbial signature at the genus level to differentiate between HNSC sample types, with cancer and cancer-adjacent tissues sharing more similarity than non-cancer tissues. Univariate analysis on 16S rRNA datasets identified significant differences in the abundance of 34 bacterial genera among the tissue types. Paired cancer and cancer-adjacent tissue analyses in 16S rRNA and TCMA datasets identified increased abundance in Fusobacterium in cancer tissues and decreased abundance of Atopobium, Rothia and Actinomyces in cancer-adjacent tissues. Furthermore, these bacteria were associated with different tumour microenvironment phenotypes. Notably, high Fusobacterium signature was associated with high neutrophil (r=0.37, P<0.0001), angiogenesis (r=0.38, P<0.0001) and granulocyte signatures (r=0.38, P<0.0001) and better overall patient survival [continuous: HR 0.8482, 95 % confidence interval (CI) 0.7758-0.9273, P=0.0003].Conclusion. Our meta-analysis demonstrates a consensus microbiota signature for HNSC, highlighting its potential importance in this disease.

Probiotic potentials of lactic acid bacteria isolated from Egyptian fermented food

Lactic acid bacteria (LAB) are of major concern due to their health benefits. Fermented food products comprise variable LAB demonstrating probiotic properties. Discovering and evaluating new probiotics in fermented food products poses a global economic and health importance. Therefore, the present work aimed to investigate and evaluate the probiotic potentials of LAB strains isolated from Egyptian fermented food. In this study, we isolated and functionally characterized 100 bacterial strains isolated from different Egyptian fermented food sources as probiotics. Only four LAB strains amongst the isolated LAB showed probiotic attributes and are considered to be safe for their implementation as feed or dietary supplements. Additionally, they were shown to exert antimicrobial activities against pathogenic bacteria and anticancer effects against the colon cancer cell line Caco-2. The Enterococcus massiliensis IS06 strain was exclusively reported in this study as a probiotic strain with high antimicrobial, antioxidant, and anti-colon cancer activity. Hitherto, few studies have focused on elucidating the impact of probiotic supplementation in vivo. Therefore, in the current study, the safety of the four strains was tested in vivo through the supplementation of rats with potential probiotic strains for 21 days. The results revealed that probiotic bacterial supplementation in rats did not adversely affect the general health of rats. The Lactiplantibacillus plantarum IS07 strain significantly increased the growth performance of rats. Furthermore, the four strains exhibited increased levels of antioxidants such as superoxide dismutase and glutathione in vivo. Consistently, all strains also showed high antioxidant activity of the superoxide dismutase enzyme in vitro. Overall, these findings demonstrated that these isolated potential probiotics harbor desirable characteristics and can be applied widely as feed additives for animals or as dietary supplements for humans to exert their health benefits and combat serious diseases.

Anticancer potential of Bacillus coagulans MZY531 on mouse H22 hepatocellular carcinoma cells via anti-proliferation and apoptosis induction

Bacillus coagulans have recently revealed its anticancer effects, but few investigations are available on their effects on liver cancer proliferation, and the precise mechanism to mark its impact on apoptosis-related signaling pathways has yet to be elucidated. The aim of this study was to evaluate the anti-proliferative effect of B. coagulans MZY531 and apoptosis induction in the mouse H22 hepatocellular carcinoma cell line. The anti-proliferative activity of B. coagulans MZY531 was evaluated by Cell Counting Kit-8 (CCK-8) assay, and cell apoptosis was revealed with Terminal Deoxynucleotidyl Transferase (TDT)-mediated dUTP Nick-End Labeling (TUNEL) staining and flow cytometric analysis. The expressions of apoptosis-related protein were determined by western blot analysis. The CCK-8 assay revealed that B. coagulans MZY531 inhibited the H22 cells proliferation in a concentration-dependent manner. TUNEL staining revealed an increased apoptosis rate in H22 cells following intervention with B. coagulans MZY531. Furthermore, flow cytometric analysis showed that B. coagulans MZY531 treatment (MOI = 50 and 100) significantly alleviated the H22 cells apoptosis compared with the control group. Western blot analysis found B. coagulans MZY531 significantly decreased level of phospho-PI3K (p-PI3K), phospho-AKT (p-AKT), and phospho-mTOR (p-mTOR) compared with the control group. Furthermore, H22 cells treatment with B. coagulans MZY531 enhanced the expression of caspase-3 and Bax and jeopardized the expression of Bcl-2. Taken together, apoptosis induction and cell proliferation inhibition via PI3K/AKT/mTOR and Bax/Bcl-2/Caspase-3 pathway are promising evidence to support B. coagulans MZY531 as a potential therapeutic agent for cancer.

Assessing the Potential Biological Activities of Postbiotics Derived from Saccharomyces cerevisiae: An In Vitro Study

A new biotherapeutic strategy involves the use of microbial bioactive substances (postbiotics) that exhibit optimum compatibility and intimate contact with the immune system of the host. This study was aimed at investigating the potential biological activities of postbiotics derived from Saccharomyces cerevisiae (PTCC 5269) (PSC) under in vitro circumstances. Based on the outcomes, the synthesized PSC possessing a high level of phenolic (102.46 ± 0.25 mg GAE/g) and flavonoid (19.87 ± 75.32 mg QE/g) content demonstrated significant radical scavenging activity (87.34 ± 0.56%); antibacterial action towards Listeria monocytogenes, Streptococcus mutans, Salmonella typhi, and Escherichia coli (in order of effectiveness) in both in vitro and food models (whole milk and ground meat); probiotics' growth-promoting activity in the fermentation medium; α-glucosidase enzyme-inhibiting and cholesterol-lowering properties in a concentration- and pH-dependent manner; reduction in the cell viability (with the significant IC₅₀ values of 34.27 and 23.58 μg/mL after 24 and 48 h, respectively); suppressed the initial (G0/G1) phase of the cell's division; induced apoptosis; and increased the expression of PTEN gene, while the IkB, RelA, and Bcl-XL genes indicated diminished expression in treated SW480 cancer cells. These multiple health-promoting functions of PSC can be extended to medical, biomedical, and food scopes, as novel biotherapeutic approaches, in order to design efficient and optimized functional food formulations or/and supplementary medications to use as adjuvant agents for preventing or/and treating chronic/acute disorders.

Identification of colorectal cancer progression-associated intestinal microbiome and predictive signature construction

OBJECTIVE

The relationship between intestinal microbiome and colorectal cancer (CRC) progression is unclear. This study aims to identify the intestinal microbiome associated with CRC progression and construct predictive labels to support the accurate assessment and treatment of CRC.

METHOD

The 192 patients included in the study were divided into stage I-II and stage III-IV CRC patients according to the pathological stages, and preoperative stools were collected from both groups for 16S rDNA sequencing of the intestinal microbiota. Pearson correlation and Spearman correlation coefficient analysis were used to analyze the differential intestinal microbiome and the correlation with tumor microenvironment and to predict the functional pathway. XGBoost model (XGB) and Random Forest model (RF) were used to construct the microbiome-based signature. The total RNA extraction from 17 CRC tumor simples was used for transcriptome sequencing.

RESULT

The Simpson index of intestinal microbiome in stage III-IV CRC were significantly lower than those in stage I-II CRC. Proteus, Parabacteroides, Alistipes and Ruminococcus etc. are significantly enriched genus in feces of CRC patients with stage III-IV. ko00514: Other types of O - glycan biosynthesis pathway is relevant with CRC progression. Alistipes indistinctus was positively correlated with mast cells, immune activators IL-6 and IL6R, and GOBP_PROTEIN_FOLDING_IN_ENDOPLASMIC_RETICULUM dominantly. The Random Forest (RF) model and eXtreme Gradient Boosting (XGBoost) model constructed with 42 CRC progression-associated differential bacteria were effective in distinguishing CRC patients between stage I-II and stage III-IV.

CONCLUSIONS

The abundance and diversity of intestinal microbiome may increase gradually with the occurrence and progression of CRC. Elevated fetal abundance of Proteus, Parabacteroides, Alistipes and Ruminococcus may contribute to CRC progression. Enhanced synthesis of O - glycans may result in CRC progression. Alistipes indistinctus may play a facilitated role in mast cell maturation by boosting IL-6 production. Alistipes indistinctus may work in the correct folding of endoplasmic reticulum proteins in CRC, reducing ER stress and prompting the survival and deterioration of CRC, which may owe to the enhanced PERK expression and activation of downstream UPR by Alistipes indistinctus. The CRC progression-associated differential intestinal microbiome identified in our study can be served as potential microbial markers for CRC staging prediction.

Tumor-targeted induction of intrinsic apoptosis in colon cancer cells by Lactobacillus plantarum and Lactobacillus rhamnosus strains

BACKGROUND

Colorectal cancer is one of the widespread and lethal types of malignancies. Recently, antineoplastic attributes of probiotics have attracted lots of attention. Here, we investigated anti-proliferative potential of the non-pathogenic strains Lactobacillus plantarum ATCC 14,917 and Lactobacillus rhamnosus ATCC 7469 on human colorectal adenocarcinoma-originated Caco-2 cells.

METHODS AND RESULTS

Caco-2 and HUVEC control cells were treated with ethyl acetate extracts of the two Lactobacillus strains to assess cell viability by MTT assay. Annexin/PI staining flow cytometry, and caspase-3, -8 and - 9 activity assays were performed to determine the type of cell death induced in extract-treated cells. Expression levels of apoptosis-related genes were evaluated by RT-PCR. Extracts from both L. plantarum and L. rhamnosus specifically targeted the Caco-2 cells and not HUVEC controls, and significantly affected the viability of the colon cancer cell line in a time- and dose-dependent manner. This effect was shown to occur through activation of the intrinsic apoptosis pathway, as indicated by the increased caspase-3 and - 9 activities. While there are limited and conflicting data about the mechanisms underlying the specific antineoplastic attributes of Lactobacillus strains, we clarified the overall induced mechanism. The Lactobacillus extracts specifically down-regulated the expression of the anti-apoptotic bcl-2 and bcl-xl, and simultaneously up-regulated the pro-apoptotic bak, bad, and bax genes in treated Caco-2 cells.

CONCLUSIONS

Ethyl acetate extracts of L. plantarum and L. rhamnosus strains could be considered as targeted anti-cancer treatments specifically inducing the intrinsic apoptosis pathway in colorectal tumor cells.

Recent Perspective of Lactobacillus in Reducing Oxidative Stress to Prevent Disease

During oxidative stress, an important factor in the development of many diseases, cellular oxidative and antioxidant activities are imbalanced due to various internal and external factors such as inflammation or diet. The administration of probiotic Lactobacillus strains has been shown to confer a range of antibacterial, anti-inflammatory, antioxidant, and immunomodulatory effects in the host. This review focuses on the potential role of oxidative stress in inflammatory bowel diseases (IBD), cancer, and liver-related diseases in the context of preventive and therapeutic effects associated with Lactobacillus. This article reviews studies in cell lines and animal models as well as some clinical population reports that suggest that Lactobacillus could alleviate basic symptoms and related abnormal indicators of IBD, cancers, and liver damage, and covers evidence supporting a role for the Nrf2, NF-κB, and MAPK signaling pathways in the effects of Lactobacillus in alleviating inflammation, oxidative stress, aberrant cell proliferation, and apoptosis. This review also discusses the unmet needs and future directions in probiotic Lactobacillus research including more extensive mechanistic analyses and more clinical trials for Lactobacillus-based treatments.

Gut microbiome in tumorigenesis and therapy of colorectal cancer

Colorectal cancer (CRC) is the malignant tumor with the highest incidence in the digestive system, and the gut microbiome plays a crucial role in CRC tumorigenesis and therapy. The gastrointestinal tract is the organ harboring most of the microbiota in humans. Changes in the gut microbiome in CRC patients suggest possible host-microbe interactions, thereby hinting the potential tumorigenesis, which provides new perspective for preventing, diagnosing, or treating CRC. In this review, we discuss the effects of gut microbiome dysbiosis on CRC, and reveal the mechanisms by which gut microbiome dysbiosis leads to CRC. Gut microbiome modulation with the aim to reverse the established gut microbial dysbiosis is a novel strategy for the prevention and treatment of CRC. In addition, this review summarizes that probiotic antagonize CRC tumorigenesis by protecting intestinal barrier function, inhibiting cancer cell proliferation, resisting oxidative stress, and enhancing host immunity. Finally, we highlight clinical applications of the gut microbiome, such as gut microbiome analysis-based biomarker screening and prediction, and microbe modulation-based CRC prevention, treatment enhancement, and treatment side effect reduction. This review provides the reference for the clinical application of gut microbiome in the prevention and treatment of CRC.

Probiotic immunonutrition impacts on colon cancer immunotherapy and prevention

The important role of the immune system in treating cancer has attracted the attention of researchers to the emergence of oncology research. Immunotherapy has shown that the immune system is important in the fight against cancer. The challenge has led researchers to analyze the impact of immunotherapy on improving the status of the immune system, modifying the resulting safety response, reducing toxicity, and improving the results. This study aimed to discuss the potential mechanisms of probiotics in preventing colon cancer. The mechanisms include the change in intestinal microbiota, the metabolic activity of microbiota, the binding and degradation of the carcinogenic compounds present in the lumen of the intestine, the production of compounds with anticancer activity, immune system modification, intestinal dysfunction, changes in host physiology, and inhibition of cell proliferation and induction of apoptosis in cancerous cells. By contrast, very few reports have shown the harmful effects of oral probiotic supplements. According to available evidence, further studies on probiotics are needed, especially in identifying bacterial species with anticancer potential, studying the survival of the strains after passing the digestive tract, reviewing potential side effects in people with a weak immune system, and ultimately consuming and repeating its use. This study emphasizes that the nutritional formula can modulate inflammatory and immune responses in cancer patients. This effect reduces acute toxicity, although the pathways and measurement of this immune response are unclear. Nutrition safety is an emerging field in oncology, and further research is required.

Anti-cancer activity of human gastrointestinal bacteria

Malignant neoplasm is one of the most incurable diseases among inflammatory diseases. Researchers have been studying for decades to win over this lethal disease and provide the light of hope to humankind. The gastrointestinal bacteria of human hold a complex ecosystem and maintain homeostasis. One hundred trillion microbes are residing in the gastrointestinal tract of human. Disturbances in the microbiota of human's gastrointestinal tract can create immune response against inflammation and also can develop diseases, including cancer. The bacteria of the gastrointestinal tract of human can secrete a variety of metabolites and bioproducts which aid in the preservation of homeostasis in the host and gut. During pathogenic dysbiosis, on the other hand, numerous microbiota subpopulations may increase and create excessive levels of toxins, which can cause inflammation and cancer. Furthermore, the immune system of host and the epithelium cell can be influenced by gut microbiota. Probiotics, which are bacteria that live in the gut, have been protected against tumor formation. Probiotics are now studied to see if they can help fight dysbiosis in cancer patients undergoing chemotherapy or radiotherapy because of their capacity to maintain gut homeostasis. Countless numbers of gut bacteria have demonstrated anti-cancer efficiency in cancer treatment, prevention, and boosting the efficiency of immunotherapy. The review article has briefly explained the anti-cancer immunity of gut microbes and their application in treating a variety of cancer. This review paper also highlights the pre-clinical studies of probiotics against cancer and the completed and ongoing clinical trials on cancers with the two most common and highly effective probiotics Lactobacillus and Bacillus spp.

Anti-Tumor Effect of Heat-Killed Bifidobacterium bifidum on Human Gastric Cancer through Akt-p53-Dependent Mitochondrial Apoptosis in Xenograft Models

Paraprobiotics, inactivated microbial cells, regulate immune system and exhibit antioxidant and anti-inflammatory activities in patients with weakened immunity or the elderly. This study evaluated the anti-tumor effects of heat-killed Bifidobacterium and Lactobacillus on human gastric cancer MKN1 cells in vitro and in vivo in xenograft animal models. First, cytotoxicity and apoptosis in MKN1 cells of 11 different heat-killed Bifidobacterium or Lactobacillus strains were examined using the MTT assay or flow cytometry, respectively. Then, BALB/c nude mice xenograft animal models were implanted with human gastric cancer MKN1 cells and orally administered a selected single or a mixture of heat-killed bacterial strains to investigate their inhibitory effect on tumor growth. In addition, the expression of p-Akt, p53, Bax, Bak, cleaved caspase-9, -3, and PARP in the tumor tissues was analyzed using Western blotting assay or immunohistochemistry staining. The results show that heat-killed B. bifidum MG731 (MG731), L. reuteri MG5346 (MG5346), and L. rhamnosus MG5200 (MG5200) induced relatively greater apoptosis than other strains in MKN1 cells. Oral administration of a single dose or a mixture of MG731, MG5346, or MG5200 significantly delayed tumor growth, and MG731 had the most effective anti-tumor effect in the xenograft model. Protein expression of p-Akt, p53, Bax, cleaved caspase-3 and -9, and PARP in tumors derived from the xenograft model correlated with the results of the immunohistochemistry staining.

Anticancer Potential of Post-Fermentation Media and Cell Extracts of Probiotic Strains: An In Vitro Study

Simple Summary

Probiotics and their metabolites are very important for human health. The aim of this research was to determine probiotic strains with the strongest inhibitory properties against intestinal cancer cells. As a result of the screening, it was possible to find two strains, i.e., Lactiplantibacillus plantarum 0991 and Levilactobacillus brevis 0983, that could inhibit the proliferation of cancer cells by induction of oxidative stress and programmed cell death. Both strains exhibit interesting anticancer properties and potential as functional food ingredients; however, the results must be confirmed in further research.

Abstract

Background: Lactic acid bacteria (LAB), many of which are probiotics, can produce health-promoting metabolites (postbiotics). Purpose: To assess the mechanism of antiproliferative action of postbiotics, post-fermentation media (PFM) and cell extracts (CEs) of several strains of LAB were studied against colon (Caco-2), and cervix (HeLa) cancer cell lines, as well as normal intestine (IEC-6) cells, were used as a comparison. Methods: Postbiotics of various LAB (n = 39) were screened for their antiproliferative activity. The effect of PFM and CEs on reactive oxygen species (ROS), mitochondrial membrane potential (MMP), ATP production, phosphatidylserine (PS) externalisation, and apoptosis-related caspases 3/7 and 9 activation was assayed. Results: PFM and CEs showed strong dose-dependent antiproliferative activity against Caco-2 cells, up to 77.8 ± 0.8% and 58.4 ± 1.6% for PFM and CEs, respectively. Stronger inhibitory activity against cancerous (Caco-2 and HeLa) cells than against normal (IEC-6) cells was observed. PFM were more inhibitory than CEs, and both generated oxidative stress in Caco-2 cells. PFM of L. plantarum 0991 and L. brevis 0983 induced apoptosis in Caco-2 cells by the mitochondrial signalling pathway. Conclusions: Anticancer activity of PFM and CEs of LAB, as well as the ability of apoptosis induction, is strain-specific.

"More Guts Than Brains?"-The Role of Gut Microbiota in Idiopathic Intracranial Hypertension

BACKGROUND

Idiopathic intracranial hypertension syndrome (IIH) is most common among obese women. Weight loss is an important factor in improving papilledema. Over the last decade, growing evidence has identified gut microbiota as a potential factor in the pathophysiology of obesity. Accordingly, we investigated whether the gut microbiome is modified in IIH patients compared with healthy controls, and provide possible new treatment venues.

METHODS

Shotgun metagenomic sequencing of the gut microbiome of 25 cases of IIH patients (according to the modified Dandy criteria) and 20 healthy controls. Participants were further stratified according to their body mass index. The total DNA from each sample was extracted using the PureLink Microbiome DNA Purification Kit A29789 (Invitrogen, Thermo Fisher Scientific, US). Library preparation was performed using the Nextera DNA Flex Library Prep Kit. Samples were sequenced on the Illumina Novaseq 6000 device. A list of bacterial species that significantly differed between the IIH patients and healthy controls was produced in addition to species diversity. In addition, patients' cohort alone was analyzed, (excluding the healthy controls), and the effect of acetazolamide treatment on their gut microbiota was analyzed.

RESULTS

IIH patients have a lower diversity of bacterial species compared with healthy individuals. These bacteria, that is, Lactobacillus ruminis (L. ruminis) (p<6.95E-08), Atopobium parvulum (p<3.9E-03), Megamonas hypermegale (p<5.61E-03), Ruminococcus gnavus (p<1.29E-02), MEL.A1 (p<3.04E-02), and Streptococcus sp. I-G2 (p<3.04E-02), were previously characterized with beneficial health effects. Moreover, we found that Lactobacillus brevis, a beneficial bacterium as well, is more abundant in acetazolamide treated patients (p<7.07E-06).

CONCLUSIONS

Gut microbiota plays a potential role in IIH etiology and therefore, can provide a promising new treatment approach for this disease.

Anti-Tumor Effects of Heat-Killed L. reuteri MG5346 and L. casei MG4584 against Human Colorectal Carcinoma through Caspase-9-Dependent Apoptosis in Xenograft Model

In this study, we examined the anti-tumor effects of heat-killed Bifidobacterium and Lactobacillus strains on human colorectal carcinoma RKO cells in in vitro and in vivo xenograft models. First, the cytotoxic and apoptotic effects of 11 different strains were examined using an MTT assay and flow cytometry, respectively. Then, xenograft BALB/c nude mice were implanted with RKO cells and orally administered with single or mixed heat-killed bacterial strains to examine their inhibitory effects on tumor growth. Additionally, the levels of cleaved caspase-9, -3, and -7 and PARP in tumor tissues were analyzed using Western blotting or immunohistochemistry staining. The results showed that RKO cells were highly susceptible to heat-killed B. bifidum MG731 and L. reuteri MG5346 and that L. casei MG4584 induced apoptosis to a greater extent than other strains. The oral administration of individual MG731, MG5346, or MG4584 significantly delayed tumor growth, and mixtures of MG5346 and MG4584 or MG731, MG5346, and MG4584 synergistically inhibited the tumor growth in the xenograft model. The expression of cleaved caspase-3, -7, and -9 and PARP in the tumor tissues was increased in Western blotting, and the expression of cleaved caspase-3 and PARP in immunohistochemistry staining was also increased. Therefore, we suggest that the use of the combination of MG5346 and MG4584 as parabiotics could effectively inhibit the growth of colorectal cancer.

Bacteria and bacterial derivatives as delivery carriers for immunotherapy

There is growing interest in the role of microorganisms in human health and disease, with evidence showing that new types of biotherapy using engineered bacterial therapeutics, including bacterial derivatives, can address specific mechanisms of disease. The complex interactions between microorganisms and metabolic/immunologic pathways underlie many diseases with unmet medical needs, suggesting that targeting these interactions may improve patient treatment. Using tools from synthetic biology and chemical engineering, non-pathogenic bacteria or bacterial products can be programmed and designed to sense and respond to environmental signals to deliver therapeutic effectors. This review describes current progress in biotherapy using live bacteria and their derivatives to achieve therapeutic benefits against various diseases.

An Update on the Effects of Probiotics on Gastrointestinal Cancers

Because of their increasing prevalence, gastrointestinal (GI) cancers are regarded as an important global health challenge. Microorganisms residing in the human GI tract, termed gut microbiota, encompass a large number of living organisms. The role of the gut in the regulation of the gut-mediated immune responses, metabolism, absorption of micro- and macro-nutrients and essential vitamins, and short-chain fatty acid production, and resistance to pathogens has been extensively investigated. In the past few decades, it has been shown that microbiota imbalance is associated with the susceptibility to various chronic disorders, such as obesity, irritable bowel syndrome, inflammatory bowel disease, asthma, rheumatoid arthritis, psychiatric disorders, and various types of cancer. Emerging evidence has shown that oral administration of various strains of probiotics can protect against cancer development. Furthermore, clinical investigations suggest that probiotic administration in cancer patients decreases the incidence of postoperative inflammation. The present review addresses the efficacy and underlying mechanisms of action of probiotics against GI cancers. The safety of the most commercial probiotic strains has been confirmed, and therefore these strains can be used as adjuvant or neo-adjuvant treatments for cancer prevention and improving the efficacy of therapeutic strategies. Nevertheless, well-designed clinical studies are still needed for a better understanding of the properties and mechanisms of action of probiotic strains in mitigating GI cancer development.

Nutritional and Health Potential of Probiotics: A Review

Several products consist of probiotics that are available in markets, and their potential uses are growing day by day, mainly because some strains of probiotics promote the health of gut microbiota, especially Furmicutes and Bacteroidetes, and may prevent certain gastrointestinal tract (GIT) problems. Some common diseases are inversely linked with the consumption of probiotics, i.e., obesity, type 2 diabetes, autism, osteoporosis, and some immunological disorders, for which the disease progression gets delayed. In addition to disease mitigating properties, these microbes also improve oral, nutritional, and intestinal health, followed by a robust defensive mechanism against particular gut pathogens, specifically by antimicrobial substances and peptides producing probiotics (AMPs). All these positive attributes of probiotics depend upon the type of microbial strains dispensed. Lactic acid bacteria (LAB) and Bifidobacteria are the most common microbes used, but many other microbes are available, and their use depends upon origin and health-promoting properties. This review article focuses on the most common probiotics, their health benefits, and the alleviating mechanisms against chronic kidney diseases (CKD), type 1 diabetes (T1D), type 2 diabetes (T2D), gestational diabetes mellitus (GDM), and obesity.

Probiotics: A Promising Candidate for Management of Colorectal Cancer

Colorectal cancer (CRC) is the World's third most frequently diagnosed cancer type. It accounted for about 9.4% mortality out of the total incidences of cancer in the year 2020. According to estimated facts by World Health Organization (WHO), by 2030, 27 million new CRC cases, 17 million deaths, and around 75 million people living with the disease will appear. The facts and evidence that establish a link between the intestinal microflora and the occurrence of CRC are quite intuitive. Current shortcomings of chemo- and radiotherapies and the unavailability of appropriate treatment strategies for CRC are becoming the driving force to search for an alternative approach for the prevention, therapy, and management of CRC. Probiotics have been used for a long time due to their beneficial health effects, and now, it has become a popular candidate for the preventive and therapeutic treatment of CRC. The probiotics adopt different strategies such as the improvement of the intestinal barrier function, balancing of natural gut microflora, secretion of anticancer compounds, and degradation of carcinogenic compounds, which are useful in the prophylactic treatment of CRC. The pro-apoptotic ability of probiotics against cancerous cells makes them a potential therapeutic candidate against cancer diseases. Moreover, the immunomodulatory properties of probiotics have created interest among researchers to explore the therapeutic strategy by activating the immune system against cancerous cells. The present review discusses in detail different strategies and mechanisms of probiotics towards the prevention and treatment of CRC.

Apoptotic Effect of Saccharomyces cerevisiae on Human Colon Cancer SW480 Cells by Regulation of Akt/NF-ĸB Signaling Pathway

Drug resistance is one of the major problems, which causes recurrence of cancers. Therefore, complementary treatments are needed to improve the impacts of chemotherapy agents. The effect of probiotics as cancer-preventing agents through involvement in the activation of apoptotic pathways has been established. The present study sought to investigate how the heat-killed form of Saccharomyces cerevisiae (as a probiotic) could affect the Akt/NF-kB-induced apoptosis in colon cancer cells, the SW480 cell line. The cytotoxic effects of heat-killed yeast (HKY) and 5-fluorouracil (5-FU, as a positive control drug) were assayed using the MTT method. Morphological changes followed by apoptosis were examined using DAPI staining. The transcription and translation level of apoptosis genes were explored with qRT-PCR and western blotting. The data were analyzed using GraphPad Prism V6.0 Software. The results showed that HKY could induce apoptosis in colon cancer cell line through downregulation of p-Akt1, Rel A, Bcl-XL, pro-caspase 3, and pro-caspase 9 expressions, and upregulation of BAX, cleaved caspase-3, and cleaved caspase-9. Besides, Akt protein expression was not affected. It is noticeable that HKY had a better modulating effect on BAX expression compared with 5-FU. It was able to modulate Akt/NF-kB signaling pathway followed by the apoptotic cascade.

Probiotics for the Chemoprotective Role Against the Toxic Effect of Cancer Chemotherapy

BACKGROUND

The processes of chemo- and radiation therapy-based clinical management of different types of cancers are associated with toxicity and side effects of chemotherapeutic agents. So, there is always an unmet need to explore agents to reduce such risk factors. Among these, natural products have generated much attention because of their potent antioxidant and antitumor effects. In the past, some breakthrough outcomes established that various bacteria in the human intestinal gut are bearing growth-promoting attributes and suppressing the conversion of pro-carcinogens into carcinogens. Hence, probiotics integrated approaches are nowadays being explored as rationalized therapeutics in the clinical management of cancer.

METHODS

Here, published literature was explored to review chemoprotective roles of probiotics against toxic and side effects of chemotherapeutics.

RESULTS

Apart from excellent anti-cancer abilities, probiotics are bearing and alleviate toxicity and side effects of chemotherapeutics, with a high degree of safety and efficiency.

CONCLUSION

Preclinical and clinical evidence suggested that due to the chemoprotective roles of probiotics against side effects and toxicity of chemotherapeutics, their integration in chemotherapy would be a judicious approach.

The Role of Probiotics in Cancer Prevention

Simple Summary

Cancer is considered one of the leading causes of human mortality in the world and is the subject of much research. The risk of developing cancer depends on genetic factors, as well as the body’s immune status. The intestinal microbiome plays very important role in maintaining homeostasis in the human body. Probiotics have gained increasing medical significance due to the beneficial effect on the human body associated with the prevention and support of the treatment of many chronic diseases, including cancer in the absence of side effects. The aim of this review was to summarize the knowledge about the effect of probiotic microorganisms in the prevention of cancer. There is a lot of evidence that the use of probiotics can play an important role in cancer prevention and support anti-cancer therapies.

Abstract

The gut microbiome can play important role in maintaining homeostasis in the human body. An imbalance in the gut microbiome can lead to pro-inflammatory immune responses and the initiation of disease processes, including cancer. The research results prove some strains of probiotics by modulating intestinal microbiota and immune response can be used for cancer prevention or/and as adjuvant treatment during anticancer chemotherapy. This review presents the latest advances in research into the effectiveness of probiotics in the prevention and treatment support of cancer. The described issues concern to the anticancer activity of probiotic microorganisms and their metabolites. In addition, we described the potential mechanisms of probiotic chemoprevention and the advisability of using probiotics.

Probiotic Lactobacillus rhamnosus Supplementation Improved Capecitabine Protective Effect against Gastric Cancer Growth in Male BALB/c Mice

The gastric cancer (GC) is biologically and genetically heterogeneous with a poorly understood carcinogenesis at the molecular level. Herein, we studied the effects of probiotics (Lactobacillus rhamnosus) on subcutaneous implantation of xenograft GC. Moreover, the effect of probiotics (L. rhamnosus) was compared with the capecitabine drug as known used drug against GC. Human GC tissue was obtained from patients with gastric adenocarcinoma and grafted into mice armpit. Probiotic (L. rhamnosus) was given to animals by gavage 2 weeks prior to GC and 4 weeks after GC induction. Also, capecitabine was orally added through feeding tube at the last week of treatment procedure. All grafted animals received cyclosporine a day before the surgery and during the study period to prevent graft rejection. Capecitabine-probiotic complex reduced the size of the axillary implanted GC when compared with control group. Furthermore, combination of capecitabine and probiotic increased apoptotic and necrotic responses in the grafted tumor, blood cells (red blood cells, white blood cells, and platelet counts) in comparison with capecitabine. Probiotic (L. rhamnosus) administration effectively improved the therapeutic index and outcomes, and also, improved the therapeutic effects of the capecitabine.

Current status of probiotics for prevention and management of gastrointestinal cancers

INTRODUCTION

Gastrointestinal cancers contribute to a significant number of cancer- associated mortality. The gastrointestinal tract harbors a multitude of microorganisms, known as the microbiota. Recently, the microbiota is considered to be an accessory organ resulting in several health benefits. The microbiota is involved in almost all aspects of an individual ranging from managing behavior to controlling metabolism, immune status and the response to a disease. Researchers are observing the modulation of microbiota in almost every disease, including cancer. Probiotics are microorganisms that can help to alter the host microbiota toward a healthy state thus providing benefits from many diseases including cancer.

AREAS COVERED

We explored the current status of the use of probiotics in cancer patients. Although probiotic bacteria can provide significant benefits to individuals suffering from cancer, the number of cancer-specific clinical products containing probiotics is not comparable to research studies showing their benefits. The lack of available products is due to several factors including a lack of risk assessment data of beneficial probiotics in cancer patients.

EXPERT OPINION

Laboratory investigations indicate a huge potential of probiotics for the prevention and management of gastrointestinal cancer, but more clinical studies are required to support their application in clinical settings.

Anti-Cancer Effects of Probiotic Lactobacillus acidophilus for Colorectal Cancer Cell Line Caco-2 through Apoptosis Induction

Background: Colorectal cancer is one of the most common cancers worldwide. Probiotics are useful and non-pathogenic microorganisms in the gastrointestinal tract, which can show anticancer activity through the induction of apoptosis. This study aimed to evaluate the antiproliferative effects of Lactobacillus acidophilus probiotic on the Caco-2 colorectal cancer cell line. Methods: The supernatant (secreted metabolites) and bacterial extract of L. acidophilus probiotics were prepared and used as an anti-proliferative agent on the colorectal cancer cell line, Caco-2 in vitro. The effects of supernatant and extract of L. acidophilus were evaluated on the viability and proliferation of cancer cells using MTT assay. Moreover, morphological alterations of cancer cells treated with supernatant and extract of L. acidophilus were evaluated by an inverted phase contrast microscope. The mRNA expression levels of apoptosis-related genes (SURVIVIN and SMAC) in treated cancer cells and untreated controls were evaluated using the Real-Time PCR method. Results: The results showed that the supernatant and extract of L. acidophilus inhibited the viability and proliferation of cancer cells in a dose and time-dependent manner. Moreover, various morphological alterations were observed in the treated cancer cells, which are indicators of apoptosis induction. The mRNA expression of SURVIVIN and SMAC genes were significantly up-regulated and downregulated in the treated cancer cells, respectively. Conclusion: The results of the present study suggested that the supernatant and extract of L.acidophilus could inhibit the viability and proliferation of colorectal cancer cell line, Caco-2through induction of apoptosis, increase the survival rate of colon cancer patients.

Antioxidant and Anticancer Activities of Lactobacillus Hilgardii Strain AG12a

Background

It has been proven that probiotic Lactobacillus bacteria have inhibitory effects on human cancer cell lines. The aim of this study is to isolate and characterize the antioxidant probiotic Lactobacillus and determine the possible anticancer activities of the selected strain.

Methods

One of the Lactobacillus strain isolated from camel doogh sample showed the high antioxidant activity by using of different methods such as resistance to hydrogen peroxide, hydroxyl radical and superoxide anions. The antioxidant strain was characterized by sequencing of 16S rRNA V2-V3 regions and the 16S-23S intergenic spacer (ITS). The methanol extract of this strain supernatant was fractionated using thin layer chromatography (TLC) and antioxidant activity of fractions was detected by 0.1% of DPPH through TLC-DPPH bioautography. In vitro anticancer activity of each fraction was investigated by using MTT and flow cytometry methods.

Results

According to the phylogenetic results, the antioxidant Lactobacillus strain was closely related to Lactobacillus hilgardii strain E91 (Accession No. EF536365). After fractionation and anti-proliferation assessments of Lactobacillus hilgardii strain AG12a extracellular materials, one of the antioxidant fraction (F4) showed maximum DPPH radical scavenging activity (IC₅₀ of 535.27 μg/mL). MTT assay of the F4 fraction demonstrated cytotoxic activity against Caco-2 with the IC50 value of 299.05 μg/mL. The cell death activity of the fraction was confirmed by flow cytometry with 30.925.

Conclusions

In this study, the anticancer and apoptotic properties of Lactobacillus hilgardii against Caco-2 cell line was reported for the first time. The isolated bioactive fraction from the extracellular methanol extract needs to be further investigated in human studies of cancer therapy.

Molecular mechanisms of postbiotics in colorectal cancer prevention and treatment

The occurrence of colorectal cancer (CRC) has been rising expeditiously and anticipated that 2.4 million new occasions of CRC will be detected yearly around the world until the year 2035. Due to some side-effects and complications of conventional CRC therapies, bioactive components such as microbial-derived biomolecules (postbiotics) have been attaining great significance by researchers for adjuvant therapy in CRC patients. The term 'postbiotics' encompasses an extensive range of complex micro- and macro-molecules (<50, 50-100, and 100< kDa) such as inactivated microbial cells, cell fractions or metabolites, which confer various physiological health benefits to the host when administered in adequate amounts. Postbiotics modulate the composition of the gut microbiota and the functionality of the immune system, as well as promote the CRC treatment effectiveness and reduces its side-effects in CRC patients due to possessing anti-oxidant, anti-proliferative, anti-inflammatory, and anti-cancer activities. Presently scientific literature confirms that postbiotics with their unique characteristics in terms of clinical (safe origin), technological (stability), and economic (low production costs) aspects can be used as promising tools for both prevent and adjuvant treat strategies in CRC patients without any serious undesirable side-effects. This review provides an overview of the concept and safety issues regarding postbiotics, with emphasis on their biological role in the prevention and treatment of CRC.

Anticancer effect of bacteria on cervical cancer: Molecular aspects and therapeutic implications

Cervical cancer is the second common cancer and the third leading cause of cancer deaths among women in less developed countries. It has been indicated that changes in vaginal microbiome play an important role in the occurrence and development of cervical cancer. However, studies have shown that probiotics play an effective role in fighting cancer by affecting pathogenic bacteria, inducing cancer cells apoptosis, and other anticancer activities. Therefore, the purpose of the present study is reviewing the anticancer effect of cervicovaginal bacteria and their potential for cervical cancer treatment.

Intestinal microbiota and colorectal cancer: changes in the intestinal microenvironment and their relation to the disease

Tools that predict the risk of colorectal cancer are important for early diagnosis, given the high mortality rate for this cancer. The composition of the intestinal microbiota is now considered to be a risk factor for the development of colorectal cancer. This discovery has motivated a growing number of studies to identify the micro-organisms responsible for the onset and/or progression of colorectal cancer. With this in mind, this review discusses the relationship between the composition of the intestinal microbiota and colorectal cancer risk. Prospective and case-control studies indicate that the intestinal microbiota of individuals with colorectal cancer usually contains a greater proportion of bacteria responsible for gastrointestinal tract inflammatory diseases, as well as bacteria that produce toxins and carcinogenic metabolites. In contrast, there tends to be a reduced presence of butyric acid-producing bacteria, probiotic bacteria and potentially probiotic bacteria. Despite these differences, the onset and development of colorectal cancer cannot be attributed to a specific micro-organism. Thus, studies focused on the formation of the intestinal microbiota and factors that modulate its composition are important for the development of approaches for colorectal cancer prevention.

The relationship between the structural characteristics of lactobacilli-EPS and its ability to induce apoptosis in colon cancer cells in vitro

Colon cancer is one of the most common cancer around the world. Exopolysaccharides (EPSs) produced by lactobacilli as potential prebiotics have been found to have an anti-tumor effect. In this study, lyophilized EPSs of four Lactobacillus spp. for their impact on apoptosis in colon cancer cells (HT-29) was evaluated using flow cytometry. The relationship between capability of a lactobacilli-EPS to induce apoptosis and their monosaccharide composition, molecular weight (MW), and linkage type was investigated by HPLC, SEC, and NMR, respectively. Changes in apoptotic-markers were examined by qPCR and Western Blotting. EPSs were capable of inhibiting proliferation in a time-dependent manner and induced apoptosis via increasing the expression of Bax, Caspase 3 and 9 while decreasing Bcl-2 and Survivin. All EPSs contained mannose, glucose, and N-acetylglucosamine with different relative proportions. Some contained arabinose or fructose. MW ranged from 102-104Da with two or three fractions. EPS of L. delbrueckii ssp. bulgaricus B3 having the highest amount of mannose and the lowest amount of glucose, showed the highest apoptosis induction. In conclusion, lactobacilli-EPSs inhibit cell proliferation in HT-29 via apoptosis. Results suggest that a relationship exists between the ability of EPS to induce apoptosis and its mannose and glucose composition.

Heat-killed probiotic bacteria induce apoptosis of HT-29 human colon adenocarcinoma cell line via the regulation of Bax/Bcl2 and caspases pathway

Apoptosis induction in cancer cells is one of the most efficient ways to treat cancer and find anticancer compounds. The aim of this study was to evaluate the cytotoxic effects of heat-killed indigenous probiotic bacteria and apoptosis induction in the HT-29 human colon adenocarcinoma cell line. The growth-inhibitory effects of probiotic heat-killed Lactobacillus brevis and Lactobacillus paracasei isolated from the traditional Iranian food "Terxine" on the HT-29 cell line were determined by 3-(4,5-dimethylthiazolyl-2)-2, 5-diphenyltetrazolium bromide (MTT) assay. Flow cytometry by Annexin-FITC kit, DNA fragmentation assay, 4,6-diamidino-2-phenylindole staining, and the expression of Bax, Bcl2, caspase-3, and caspase-9 were used to analyze apoptosis. MTT results demonstrated that the heat-killed bacteria inhibited the proliferation of HT-29 cells and induced apoptosis in a time-, dose-, and strain-dependent manner. The results demonstrated that both bacteria could induce apoptosis in the HT-29 cell line. Heat-killed probiotic bacteria increased the expression of Bax, caspase-3, and caspase-9 mRNA levels in HT-29 cell lines. Also, heat-killed probiotic bacteria reduced the expression of Bcl2 in HT-29 cells. The heat-killed probiotic bacteria in this study exhibited potent growth inhibitory effects on cancer cells. The results demonstrated that L. brevis has a greater ability to inhibit the growth of HT-29 cells and induce apoptosis, compared with L. paracasei. It is proposed that these bacteria can be used as biological products for the treatment and prevention of cancer, pending further investigation.

Probiotic Bacteria: A Promising Tool in Cancer Prevention and Therapy

Gut microbiota is widely considered to be one of the most important components to maintain balanced homeostasis. Looking forward, probiotic bacteria have been shown to play a significant role in immunomodulation and display antitumour properties. Bacterial strains could be responsible for detection and degradation of potential carcinogens and production of short-chain fatty acids, which affect cell death and proliferation and are known as signaling molecules in the immune system. Lactic acid bacteria present in the gut has been shown to have a role in regression of carcinogenesis due to their influence on immunomodulation, which can stand as a proof of interaction between bacterial metabolites and immune and epithelial cells. Probiotic bacteria have the ability to both increase and decrease the production of anti-inflammatory cytokines which play an important role in prevention of carcinogenesis. They are also capable of activating phagocytes in order to eliminate early-stage cancer cells. Application of heat-killed probiotic bacteria coupled with radiation had a positive influence on enhancing immunological recognition of cancer cells. In the absence of active microbiota, murine immunity to carcinogens has been decreased. There are numerous cohort studies showing the correlation between ingestion of dairy products and the risk of colon and colorectal cancer. An idea of using probiotic bacteria as vectors to administer drugs has emerged lately as several papers presenting successful results have been revealed. Within the next few years, probiotic bacteria as well as gut microbiota are likely to become an important component in cancer prevention and treatment.

Germinated brown rice combined with Lactobacillus acidophilus and Bifidobacterium animalis subsp. lactis inhibits colorectal carcinogenesis in rats

Colorectal cancer is a common cancer strongly associated with diet. Certain probiotics and prebiotics possess an inhibitory activity against colorectal cancer, while synbiotics may be more effective in preventing this cancer than either prebiotics or probiotics alone. Germinated brown rice (GBR) is considered as a candidate prebiotics with anticancer potential. However, the effect of GBR combined with probiotics on colorectal cancer is not clear. The present study investigated the preventive effect of combination of GBR and Lactobacillus acidophilus, Bifidobacterium animalis subsp. lactis, or both on colorectal carcinogenesis and the possible mechanism in rats treated with 1,2-dimethylhydrazine (DMH) and dextran sulfate sodium (DSS). DMH/DSS treatment induced preneoplastic aberrant crypt foci (ACF) and mucin-depleted foci (MDF), reduced superoxide dismutase (SOD) activity, increased anti-apoptotic Bcl-2 expression, and decreased the expression of pro-apoptotic p53, Bax, and caspase-3 in the colon. Germinated brown rice alone or combined with probiotics inhibited the formation of MDF in the middle colon, enhanced the colonic expression of p53 and Bax, and increased the ratio of Bax/Bcl-2. Combined treatment of GBR and probiotics inhibited the formation of ACF-producing sialomucin (SIM-ACF) and recovered the activity of SOD in the colon. Combination of GBR and L. acidophilus further increased caspase-3 expression and decreased Bcl-2 expression. These findings suggest that GBR combined with L. acidophilus and/or B. animalis subsp. lactis may inhibit colorectal carcinogenesis by enhancing antioxidative capacity and inducing apoptosis. This synbiotics may be a potential functional food or chemopreventive agent for controlling colorectal cancer.

Anti-proliferative, pro-apoptotic and anti-oxidative activity of Lactobacillus and Bifidobacterium strains: A review of mechanisms and therapeutic perspectives

Lactobacillus and Bifidobacterium strains, their isolated constituents and substances that they secrete exert various anti-cancer actions, resulting from their anti-proliferative, pro-apoptotic and anti-oxidant properties. They can express and secrete anti-oxidant enzymes, bind reactive oxygen species, release small molecular weight anti-oxidants and chelate transition metals, preventing detrimental actions of many carcinogens. Lactobacillus and Bifidobacterium can interact with proteins regulating the cell cycle inhibiting proliferation of cancer cells, which often are intrinsically resistant to apoptosis. Lactobacilli and bifidobacteria can break this resistance through activation of pro-caspases and downregulation of the anti-apoptotic Bcl-2 and upregulation of pro-apoptotic Bax proteins. Anti-cancer effects of these bacteria can be also associated with their multi-pathways action in the microbiota. However, exact mechanism of their anti-cancer action is poorly known and needs further studies, which are justified by the important role of these bacteria in cancer biology as well as their potential preventive and therapeutic use.

Anticancer effects of the microbiome and its products

The human gut microbiome modulates many host processes, including metabolism, inflammation, and immune and cellular responses. It is becoming increasingly apparent that the microbiome can also influence the development of cancer. In preclinical models, the host response to cancer treatment has been improved by modulating the gut microbiome; this is known to have an altered composition in many diseases, including cancer. In addition, cancer treatment with microbial agents or their products has the potential to shrink tumours. However, the microbiome could also negatively influence cancer prognosis through the production of potentially oncogenic toxins and metabolites by bacteria. Thus, future antineoplastic treatments could combine the modulation of the microbiome and its products with immunotherapeutics and more conventional approaches that directly target malignant cells.

Review of the mechanisms of probiotic actions in the prevention of colorectal cancer

The purpose of this review is to discuss the potential mechanisms of probiotics action in colorectal cancer prevention. In this regard, the composition of the intestinal microbiota is considered as an important risk factor in the development of colorectal cancer, and probiotics are able to positively modulate the composition of this microbiota. Studies have shown that the regular consumption of probiotics could prevent the development of colorectal cancer. In this respect, in vitro and experimental studies suggest some potential mechanisms responsible for this anticarcinogenic action. The mechanisms include modification of the intestinal microbiota composition, changes in metabolic activity of the microbiota, binding and degradation of carcinogenic compounds present in the intestinal lumen, production of compounds with anticarcinogenic activity, immunomodulation, improvement of the intestinal barrier, changes in host physiology, inhibition of cell proliferation, and induction of apoptosis in cancer cells. In contrast, very few reports demonstrate adverse effects of probiotic oral supplementation. In light of the present evidence, more specific studies are needed on probiotic bacteria, especially regarding the identification of the bacterial strains with greater anticarcinogenic potential; the verification of the viability of these strains after passing through the gastrointestinal tract; the investigation of potential adverse effects in immunocompromised individuals; and finally establishing the dosage and frequency of use.

Autochthonous Bacterial Isolates Successfully Stimulate In vitro Peripheral Blood Leukocytes of the European Sea Bass (Dicentrarchus labrax)

Commercially available probiotics are routinely administered as feed supplements in aquaculture important species. Among them, the European sea bass (Dicentrarchus labrax) is the most widely reared fish in the Mediterranean, whose rearing systems are highly variable between countries, affecting at some level the sustainability of production. After random isolation of autochthonous gut bacteria of the sea bass, their identification and pathogenicity testing, we have selected three potentially probiotic isolates; Pseudoalteromonas sp., Alteromonas sp., and Enterovibrio coralii. Selected isolates were tested and their immunostimulative efficiency was compared with a commercially available Lactobacillus casei isolate, inferring inflammatory, apoptotic and anti-pathogen response of sea bass’ peripheral blood leukocytes. Phagocytic activity, respiratory burst, and expression of lysozyme, Mx protein, caspase 3, TNF-α, IL-10 genes was measured 1, 3, 5, and 12 h post-stimulation by four bacterial isolates to evaluate early kinetics of the responses. Best immunostimulative properties were observed in Pseudoalteromonas-stimulated leukocytes, followed by Alteromonas sp. and L. casei, while Enterovibrio coralii failed to induce significant stimulation. Based on such in vitro assay intestinal autochthonous bacterial isolates showed to have better immunostimulative effect in sea bass compared to aquaculture-widely used L. casei, and further steps need to engage tank and field feeding trials to evaluate long-term prophylactic suitability of the chosen isolates. A panel of biomarkers that represent pro-/anti-inflammatory, pro-/anti-apoptotic, and anti-bacteria/viral responses of the fish should be taken into consideration when evaluating the usefulness of the potential probiotic in aquaculture.

The Antimetastatic and Antiangiogenesis Effects of Kefir Water on Murine Breast Cancer Cells

Background. Kefir is a unique cultured product that contains beneficial probiotics. Kefir culture from other parts of the world exhibits numerous beneficial qualities such as anti-inflammatory, immunomodulation, and anticancer effects. Nevertheless, kefir cultures from different parts of the world exert different effects because of variation in culture conditions and media. Breast cancer is the leading cancer in women, and metastasis is the major cause of death associated with breast cancer. The antimetastatic and antiangiogenic effects of kefir water made from kefir grains cultured in Malaysia were studied in 4T1 breast cancer cells. Methods. 4T1 cancer cells were treated with kefir water in vitro to assess its antimigration and anti-invasion effects. BALB/c mice were injected with 4T1 cancer cells and treated orally with kefir water for 28 days. Results. Kefir water was cytotoxic toward 4T1 cells at IC₅₀ (half-maximal inhibitory concentration) of 12.5 and 8.33 mg/mL for 48 and 72 hours, respectively. A significant reduction in tumor size and weight (0.9132 ± 0.219 g) and a substantial increase in helper T cells (5-fold) and cytotoxic T cells (7-fold) were observed in the kefir water–treated group. Proinflammatory and proangiogenic markers were significantly reduced in the kefir water–treated group. Conclusions. Kefir water inhibited tumor proliferation in vitro and in vivo mainly through cancer cell apoptosis, immunomodulation by stimulating T helper cells and cytotoxic T cells, and anti-inflammatory, antimetastatic, and antiangiogenesis effects. This study brought out the potential of the probiotic beverage kefir water in cancer treatment.

Selective induction of apoptosis in human gastric cancer cells by Lactobacillus kefiri (PFT), a novel kefir product

The present study was undertaken to evaluate the effect of Lactobacillus kefiri (PFT), a novel kefir product, on apoptosis of gastric cancer cells (AGS), breast cancer cells (4T1), and human peripheral blood mononuclear cells (PBMCs). Cells were cultured with PFT and apoptosis was determined by flow cytometry using 7-AAD dye and cytospin preparation. Mitochondrial dysfunction and expression of Bcl2 were monitored by flow cytometry. Results showed that PFT induced apoptosis in AGS gastric cancer cells in a dose-dependent manner. Apoptosis was detected at a concentration of 0.3 mg/ml (20.8%), increased to 25.8% at 0.6 mg/ml, 37% at 1.2 mg/ml, 53.1% at 2.5 mg/ml, and peaked at 66.3% at 5.0 mg/ml. Apoptosis is associated with the decreased polarization of mitochondrial membrane potential (MMP) and decreased Bcl2 expression. PFT-treated AGS cells manifested membrane blebbing, nuclear condensation, and fragmentation as identified in cytospin cytocentrifuge Giemsa stained preparations. On the other hand, flow cytometry analysis showed that PFT did not induce apoptosis in 4T1 breast cancer cells nor in PBMCs. These results suggest that PFT is safe for white blood cells and selectively induces apoptotic effects in gastric cancer cells. Hence, it may have potential as a therapeutic agent for the treatment of gastric cancers.

Bifidobacteria Expressing Tumstatin Protein for Antitumor Therapy in Tumor-Bearing Mice

Tumstatin (Tum) is a powerful angiostatin that inhibits proliferation and induces apoptosis of tumorous vascular endothelial cells. A nonpathogenic and anaerobic bacterium, Bifidobacterium longum (BL), selectively localizes to and proliferates in the hypoxia location within solid tumor. The aims of this study were to develop a novel delivery system for Tum using engineered Bifidobacterium and to investigate the inhibitory effect of Tum on tumor in mice. A vector that enabled the expression of Tum under the control of the pBBADs promoter of BL was constructed and transformed into BL NCC2705 by electroporation. The mouse colon carcinoma cells CT26 (1 × 10(7)/mL) were subcutaneously inserted in the left armpit of BALB/c mice. The tumor-bearing mice were treated with Tum-transformed BL, and green fluorescent protein (GFP)-transformed BL was used as a negative control. The microvessel density (MVD) in the transplanted tumor was determined, and terminal deoxynucleotidyl transferase-mediated 2'-deoxyuridine 5'-triphosphate nick end labeling was used to detect apoptosis of vascular endothelial cells in transplanted tumor. The in vitro expression of Tum was examined in BL after l-arabinose induction. Bifidobacterium longum with pBBAD-Tum (BL-Tum) showed significant antitumor effect in tumor-bearing mice. The weight, volume, growth, and MVD, as well as the percentage of apoptotic vascular endothelial cells of transplanted tumors in the tumor-bearing mice treated with Tum-transformed BL were all significantly lower than those in the GFP negative control group. Intragastric administration, injection in tumor and vena caudalis injection of Tum-transformed BL exerted marked antitumor effects in tumor-bearing mice. This is the first demonstration of the utilization of Tum-transformed BL as a specific gene delivery system for treating tumor.

A pilot study on the effect of Lactobacillus casei Zhang on intestinal microbiota parameters in Chinese subjects of different age

Ageing of the population is an imminent global problem. Lactobacillus casei Zhang (LcZ) was isolated from Inner Mongolian fermented milk, koumiss. LcZ possesses numerous probiotic properties in in vitro tests and in animal models. However, it has never been tested in any human trial. In the current study, the impact of oral consumption of LcZ on different age groups was tested. Chinese subjects, including 10 young, 7 middle-aged and 7 elderly volunteers (with mean age of 24.3, 47.6 and 64.7, respectively), were recruited. Each subject took 10.6 log10 cfu LcZ daily for a continuous period of 28 days. Several parameters, including the amounts of LcZ and four selected groups of bacteria, change of bacterial diversity, short chain fatty acids (SCFA) and total bile acids (TBA), were monitored in faecal samples collected from the subjects before starting, during and after stopping oral LcZ consumption. The consumption of LcZ exhibited beneficial effects to the subjects by modulating faecal microbiota in a temporal manner with a prolonged elevation of SCFA and reduction of TBA. The potentially harmful Pseudomonas and Acinetobacter genera were suppressed by the probiotic administration. Furthermore, a moderately divergent response was observed in the indigenous gut populations of Bifidobacterium and Bacteroides fragilis group in different age subjects. Taken together, the current study has provided proof on the positive effect of probiotic consumption and crucial insights into the design and application of probiotic-based products to users of different age segments.

The impact of date palm fruits and their component polyphenols, on gut microbial ecology, bacterial metabolites and colon cancer cell proliferation

The fruit of the date palm (Phoenix dactylifera L.) is a rich source of dietary fibre and polyphenols. We have investigated gut bacterial changes induced by the whole date fruit extract (digested date extract; DDE) and its polyphenol-rich extract (date polyphenol extract; DPE) using faecal, pH-controlled, mixed batch cultures mimicking the distal part of the human large intestine, and utilising an array of microbial group-specific 16S rRNA oligonucleotide probes. Fluorescence microscopic enumeration indicated that there was a significant increase in the growth of bifidobacteria in response to both treatments, whilst whole dates also increased bacteroides at 24 h and the total bacterial counts at later fermentation time points when compared with DPE alone. Bacterial metabolism of whole date fruit led to the production of SCFA, with acetate significantly increasing following bacterial incubation with DDE. In addition, the production of flavonoid aglycones (myricetin, luteolin, quercetin and apigenin) and the anthocyanidin petunidin in less than 1 h was also observed. Lastly, the potential of DDE, DPE and metabolites to inhibit Caco-2 cell growth was investigated, indicating that both were capable of potentially acting as antiproliferative agents in vitro, following a 48 h exposure. This potential to inhibit growth was reduced following fermentation. Together these data suggest that consumption of date fruits may enhance colon health by increasing beneficial bacterial growth and inhibiting the proliferation of colon cancer cells. This is an early suggestion that date intake by humans may aid in the maintenance of bowel health and even the reduction of colorectal cancer development.

Apoptotic effect of a novel kefir product, PFT, on multidrug-resistant myeloid leukemia cells via a hole-piercing mechanism

We examined the apoptotic effect of a novel Probiotics Fermentation Technology (PFT) kefir grain product; PFT is a natural mixture composed primarily of Lactobacillus kefiri P-IF, a specific strain of L. kefiri with unique growth characteristics. The aim of this study was to examine the apoptotic effect of PFT on human multidrug-resistant (MDR) myeloid leukemia (HL60/AR) cells in vitro and explore the mechanistic approach underlying its effect. HL60/AR cells were cultured with PFT (0.6–5.0 mg/ml) for 3 days. The apoptotic effect of PFT was assessed through examination of percent apoptosis, caspase 3 activation, Bcl-2 expression levels and changes in mitochondrial membrane potential (MMP). PFT induced apoptosis in HL60/AR cells in a dose-dependent manner which was maximal at 67.5% for 5 mg/ml. Induction of apoptosis was associated with activation of caspase 3, decreased expression of Bcl-2 and decreased polarization of MMP. In addition, PFT showed a unique characteristic of piercing holes in HL60/AR cells, as indicated by AFM studies. This hole induction may be responsible for the apoptotic effect on cancer cells. These results suggest that PFT may act as a potential therapy for the treatment of MDR leukemia.

Human gut microbiome and risk for colorectal cancer

We tested the hypothesis that an altered community of gut microbes is associated with risk of colorectal cancer (CRC) in a study of 47 CRC case subjects and 94 control subjects. 16S rRNA genes in fecal bacterial DNA were amplified by universal primers, sequenced by 454 FLX technology, and aligned for taxonomic classification to microbial genomes using the QIIME pipeline. Taxonomic differences were confirmed with quantitative polymerase chain reaction and adjusted for false discovery rate. All statistical tests were two-sided. From 794217 16S rRNA gene sequences, we found that CRC case subjects had decreased overall microbial community diversity (P = .02). In taxonomy-based analyses, lower relative abundance of Clostridia (68.6% vs 77.8%) and increased carriage of Fusobacterium (multivariable odds ratio [OR] = 4.11; 95% confidence interval [CI] = 1.62 to 10.47) and Porphyromonas (OR = 5.17; 95% CI = 1.75 to 15.25) were found in case subjects compared with control subjects. Because of the potentially modifiable nature of the gut bacteria, our findings may have implications for CRC prevention.