Probiotics in Cancer

Bacteria and Carcinogenesis and the Management of Cancer: A Narrative Review

There is a widely known relationship between certain microbes and cancer progression. For instance, Helicobacter pylori is associated with the occurrence of gastric cancer, while HPV is associated with cervical and head and neck cancers. Recent studies have uncovered novel and important associations between bacterial presence and tumor formation and treatment response. Apart from the influence of the intestinal microbiome on cancer, the local activity of bacteria affects disease properties as well. Bacteria can localize within tumors in less vascularized niches. Their presence mediates the activity of signaling pathways, which contribute to tumorigenesis. Furthermore, they affect the composition of the tumor microenvironment, a highly complex structure composed of immunoregulatory cells and secreted inflammatory mediators. Recently, researchers have analyzed the properties of bacteria to develop novel anticancer strategies. The aim of this review is to discuss the latest findings regarding the relationships between bacteria and cancer and the properties of bacteria that could be used to kill cancer cells.

The Role of RS Type 2 (High-Amylose Maize Starch) in the Inhibition of Colon Cancer: A Comprehensive Review of Short-Chain Fatty Acid (SCFA) Production and Anticancer Mechanisms

Dietary fiber, especially resistant starch (RS) Type 2 (RS2) found in high-amylose maize starch (HAMS), is vital for gut health and helps prevent colon cancer. In contrast to most nutrients, dietary fiber is not degraded by the intestinal enzymes; it reaches the distal parts of the gut, where it is fermented by the gut microbiota into short-chain fatty acids (SCFAs), such as acetate, propionate, and butyrate. SCFAs energize colonocytes, reduce inflammation, and enhance gut immunity. HAMS is absorbed in the colon, where it ferments to create SCFAs that feed good gut flora and have antiinflammatory and antiproliferative effects. RS2 in HAMS modulates gene signaling, activates tumor-suppressor genes like tumor suppressor protein (p53), exhibits antidiabetic, cholesterol-lowering, and antiinflammatory effects. Incorporation of RS2-rich sources enhances gut barriers, decreases colorectal cancer biomarkers, and counteracts the negative impacts of low-fiber Western diets, making HAMS a promising functional food for chronic disease prevention and health promotion.

Immuno-oncological Challenges and Chemoresistance in Veterinary Medicine: Probiotics as a New Strategic Tool

Cancer has the highest death rates due to increased immuno-oncological (IO) challenges and chemoresistance caused by gut dysbiosis, whereas administration of probiotics may reverse these responses against anticancer therapies. Recently, immunotherapeutics have extensively been focused for significant advancements in pharmacological drug discovery and clinical outcomes. Mammals have intestinal epithelial cells, mucosal immune cells, and indigenous gut microbiota which may reshape immunotherapeutics efficacy. These include use of T-cell immune checkpoint inhibitors (ICPI), genetically engineered T-cells, tumor vaccines, monoclonal antibodies (mAbs), and anti-B- and T-cell antibodies. Immunotherapeutics for cancer treatment became popular in both veterinary and human health care systems due to their strong inhibitory actions against PD-1 and CTLA-4 to check tumorigenesis. IO issues in animals also need special attention, where caninized mAbs targeting CD-20 and CD-52 have been clinically used in treating canine B-cell and T-cell lymphomas, respectively. Probiotics appeared as strong immunotherapeutics that might be shaping the epigenetics of the organisms specifically in animal breeding practices for desired features, but limited literature regarding the immunomodulatory effects in humans and animals is available. In addition, considering the important role of probiotics in humans and veterinary medicine, a new perspective on the probiotic-mediated modulation of ncRNAs (miRNAs, lncRNAs, circRNAs) is also highlighted and would be a new therapeutic tool. This review provides insight into the cellular processes and pharmacological activities for treating veterinary infectious diseases and covers small drug molecules as ncRNA-modulators in veterinary medicine.

Synergistic Interactions Between Probiotics and Anticancer Drugs: Mechanisms, Benefits, and Challenges

Research into the role of probiotics-often referred to as "living supplements"-in cancer therapy is still in its early stages, and uncertainties regarding their effectiveness remain. Relevantly, chemopreventive and therapeutic effects of probiotics have been determined. There is also substantial evidence supporting their potential in cancer treatment such as immunotherapy. Probiotics employ various mechanisms to inhibit cancer initiation and progression. These include colonizing and protecting the gastrointestinal tract (GIT), producing metabolites, inducing apoptosis and autophagy, exerting anti-inflammatory properties, preventing metastasis, enhancing the effectiveness of immune checkpoint inhibitors (ICIs), promoting cancer-specific T cell infiltration, arresting the cell cycle, and exhibiting direct or indirect synergistic effects with anticancer drugs. Additionally, probiotics have been shown to activate tumor suppressor genes and inhibit pro-inflammatory transcription factors. They also increase reactive oxygen species production within cancer cells. Synergistic interactions between probiotics and various anticancer drugs, such as cisplatin, cyclophosphamide, 5-fluorouracil, trastuzumab, nivolumab, ipilimumab, apatinib, gemcitabine, tamoxifen, sorafenib, celecoxib and irinotecan have been observed. The combination of probiotics with anticancer drugs holds promise in overcoming drug resistance, reducing recurrence, minimizing side effects, and lowering treatment costs. In addition, fecal microbiota transplantation (FMT) and prebiotics supplementation has increased cytotoxic T cells within tumors. However, probiotics may leave some adverse effects such as risk of infection and gastrointestinal effects, antagonistic effects with drugs, and different responses among patients. These findings highlight insights for considering specific strains and engineered probiotic applications, preferred doses and timing of treatment, and personalized therapies to enhance the efficacy of cancer therapy. Accordingly, targeted interventions and guidelines establishment needs extensive randomized controlled trials as probiotic-based cancer therapy has not been approved by Food and Drug Administration (FDA).

Microbiome and bladder cancer: the role of probiotics in treatment

Bladder cancer (BCa) remains a significant global health challenge, with increasing interest in the role of the bladder microbiome in its pathogenesis, progression and treatment outcomes. The complex relationship between bladder cancer and the microbiome, as well as the potential impact of probiotics on treatment effectiveness, is currently under investigation. Research suggests that the microbiota may influence BCa recurrence prevention and enhance the efficacy of the Bacillus Calmette-Guérin (BCG) vaccine. Recent studies reveal differences in the bladder microbiome between individuals without bladder cancer and those with the disease. In the healthy bladder, Streptococcus and Lactobacillus are consistently identified as the most prevalent genera. However, in men, the predominant bacterial genera are Staphylococcus, Corynebacterium and Streptococcus, while in women with bladder cancer, Gardnerella and Lactobacillus are dominant. Probiotics, particularly Lactobacillus spp., can exhibit anti-tumor properties by competing with pathogenic strains involved in carcinogenesis or by producing regulatory substances. They regulate cancer signaling, induce apoptosis, inhibit mutagenic activity, downregulate oncogene expression, induce autophagy, inhibit kinases, reactivate tumor suppressors and prevent metastasis. These mechanisms have shown promising results in both preclinical and some clinical studies.

Exploring micronutrients and microbiome synergy: pioneering new paths in cancer therapy

The human microbiome is the complex ecosystem consisting of trillions of microorganisms that play a key role in developing the immune system and nutrient metabolism. Alterations in the gut microbiome have been linked to cancer initiation, progression, metastasis, and response to treatment. Accumulating evidence suggests that levels of vitamins and minerals influence the gut environment and may have implications for cancer risk and progression. Bifidobacterium has been reported to reduce the colorectal cancer risk by binding to free iron. Additionally, zinc ions have been shown to activate the immune cells and enhance the effectiveness of immunotherapy. Higher selenium levels have been associated with a reduced risk of several cancers, including colorectal cancer. In contrast, enhanced copper uptake has been implicated in promoting cancer progression, including colon cancer. The interaction between cancer and gut bacteria, as well as dysbiosis impact has been studied in animal models. The interplay between prebiotics, probiotics, synbiotics, postbiotics and gut bacteria in cancer offers the diverse physiological benefits. We also explored the particular probiotic formulations like VSL#3, Prohep, Lactobacillus rhamnosus GG (LGG), etc., for their ability to modulate immune responses and reduce tumor burden in preclinical models. Targeting the gut microbiome through antibiotics, bacteriophage, microbiome transplantation-based therapies will offer a new perspective in cancer research. Hence, to understand this interplay, we outline the importance of micronutrients with an emphasis on the immunomodulatory function of the microbiome and highlight the microbiome's potential as a target for precision medicine in cancer treatment.

Understanding the relationship between breast cancer, immune checkpoint inhibitors, and gut microbiota: a narrative review

Background and Objective

The composition of gut microbiota plays an important role in predicting and influencing outcomes of cancer treated with immunotherapy. Our objective is to summarize the role of gut microbiota and immunotherapy in breast cancer.

Methods

A systematic search from inception until July 2024 of key search terms including immunity, breast neoplasm, gastrointestinal microbiome/microbiota, fecal microbiota transplantation, pro- and prebiotics, antibiotics and immunotherapy using EMBASE, MEDLINE and CENTRAL was conducted. The results were screened by two reviewers independently and synthesized and presented descriptively.

Key Content and Findings

Thirteen studies (5 clinical, 8 pre-clinical) met the eligibility criteria and were published from 2020-2024. Clinical studies showed that the composition and diversity of gut microbiota was associated with patient response to immunotherapy. In pre-clinical studies, dysbiotic states induced by obesity, antibiotics, and diet were associated with immunosuppression and influenced response to programmed cell death-ligand 1 (PD-L1) inhibitors. Microbiota-modulating treatments such as probiotics showed the ability to enhance response to immunotherapy, indicating their potential use as adjunct therapies in breast cancer treatment.

Conclusions

The composition of gut microbiota could help predict the chance of response to immunotherapy, and modulating gut microbiota has the potential to enhance the efficacy of chemo-immunotherapy in breast cancer. However, the available data relating to breast cancer are limited. Larger prospective studies are required to further elucidate their role as a biomarker and treatment.

A Critical Review on the Role of Probiotics in Lung Cancer Biology and Prognosis

Lung cancer remains the leading cause of cancer-related deaths worldwide. According to the American Cancer Society (ACS), it ranks as the second most prevalent type of cancer globally. Recent findings have highlighted bidirectional gut-lung interactions, known as the gut-lung axis, in the pathophysiology of lung cancer. Probiotics are live microorganisms that boost host immunity when consumed adequately. The immunoregulatory mechanisms of probiotics are thought to operate through the generation of various metabolites that impact both the gut and distant organs (e.g., the lungs) through blood. Several randomized controlled trials have highlighted the pivotal role of probiotics in gut health especially for the prevention and treatment of malignancies, with a specific emphasis on lung cancer. Current research indicates that probiotic supplementation positively affects patients, leading to a suppression in cancer symptoms and a shortened disease course. While clinical trials validate the therapeutic benefits of probiotics, their precise mechanism of action remains unclear. This narrative review aims to provide a comprehensive overview of the present landscape of probiotics in the management of lung cancer.

Appraisal of postbiotics in cancer therapy

Cancer remains a multifactorial disease with an increased mortality rate around the world for the past several decades. Despite advancements in treatment strategies, lower survival rates, drug-associated side effects, and drug resistance create a need for novel anticancer agents. Ample evidence shows that imbalances in the gut microbiota are associated with the formation of cancer and its progression. Altering the gut microbiota via probiotics and their metabolites has gained attention among the research community as an alternative therapy to treat cancer. Probiotics exhibit health benefits as well as modulate the immunological and cellular responses in the host. Apart from probiotics, their secreted products like bacteriocins, exopolysaccharides, short-chain fatty acids, conjugated linoleic acid, peptidoglycan, and other metabolites are found to possess anticancer activity. The beneficiary role of these postbiotic compounds is widely studied for characterizing their mechanism and mode of action that reduces cancer growth. The present review mainly focuses on the postbiotic components that are employed against cancer with their reported mechanism of action. It also describes recent research works carried out so far with specific strain and anticancer activity of derived compounds both in vitro and in vivo, validating that the probiotic approach would pave an alternative way to reduce the burden of cancer.

Nutrition Intervention and Microbiome Modulation in the Management of Breast Cancer

Breast cancer (BC) is one of the most common cancers worldwide and a leading cause of cancer-related deaths among women. The escalating incidence of BC underscores the necessity of multi-level treatment. BC is a complex and heterogeneous disease involving many genetic, lifestyle, and environmental factors. Growing evidence suggests that nutrition intervention is an evolving effective prevention and treatment strategy for BC. In addition, the human microbiota, particularly the gut microbiota, is now widely recognized as a significant player contributing to health or disease status. It is also associated with the risk and development of BC. This review will focus on nutrition intervention in BC, including dietary patterns, bioactive compounds, and nutrients that affect BC prevention and therapeutic responses in both animal and human studies. Additionally, this paper examines the impacts of these nutrition interventions on modulating the composition and functionality of the gut microbiome, highlighting the microbiome-mediated mechanisms in BC. The combination treatment of nutrition factors and microbes is also discussed. Insights from this review paper emphasize the necessity of comprehensive BC management that focuses on the nutrition-microbiome axis.

Cereal-based fermented foods as microbiota-directed products for improved child nutrition and health in sub-Saharan Africa

Several strategies, programs and policies have long been developed and implemented to alleviate child malnutrition in sub-Saharan African countries. However, stunting and wasting still persist at an alarming rate, suggesting that alternative strategies are needed to induce faster progress toward the 2030 SDGs targets of reducing malnutrition. Gut microbiota-directed intervention is now being recognized as an unconventional powerful approach to mitigate malnutrition and improve overall child health. In an African setting, manufactured probiotic and synbiotic foods or supplements may not be successful owing to the non-affordability and high attachment of African populations to their food tradition. This review analyses the potential of indigenous fermented cereal-based products including porridges, doughs, beverages, bread- and yoghurt-like products, to be used as microbiota-directed foods for over 6 months children. The discussion includes relevant strategies to effectively enhance the beneficial effects of these products on gut microbiota composition for improved child health and nutrition in sub-Saharan Africa. Characterization of probiotic features and general safety of food processing in sub-Saharan Africa as well as randomized clinical studies are still lacking to fully ascertain the health effects and suitability of these fermented foods in preventing and treating child malnutrition and diarrhea.

Advancements in the impact of human microbiota and probiotics on leukemia

The human gut microbiota is a complex ecosystem that plays a crucial role in promoting the interaction between the body and its environment. It has been increasingly recognized that the gut microbiota has diverse physiological functions. Recent studies have shown a close association between the gut microbiota and the development of certain tumors, including leukemia. Leukemia is a malignant clonal disease characterized by the uncontrolled growth of one or more types of blood cells, which is the most common cancer in children. The imbalance of gut microbiota is linked to the pathological mechanisms of leukemia. Probiotics, which are beneficial microorganisms that help maintain the balance of the host microbiome, play a role in regulating gut microbiota. Probiotics have the potential to assist in the treatment of leukemia and improve the clinical prognosis of leukemia patients. This study reviews the relationship between gut microbiota, probiotics, and the progression of leukemia based on current research. In addition, utilizing zebrafish leukemia models in future studies might reveal the specific mechanisms of their interactions, thereby providing new insights into the clinical treatment of leukemia. In conclusion, further investigation is still needed to fully understand the accurate role of microbes in leukemia.

The role of Bifidobacterium in longevity and the future of probiotics

This review explores the role and health impacts of probiotics, focusing specifically on Bifidobacterium spp. It highlights the functionalities that Bifidobacteria can provide, underscored by the historical evolution of definitions and technological advancements related to probiotics. By examining the association between Bifidobacteria and longevity, this review suggests new avenues for health enhancement. Highlighting case studies of centenarians, it presents examples related to human aging, illuminating the potential links to longevity through research on Bifidobacterium strains found in centenarians. This review not only emphasizes the importance of current research but also advocates for further investigation into the health benefits of Bifidobacteria, underlining the necessity for continuous study in the nutraceutical field.

Harnessing probiotic foods: managing cancer through gut health

One of the greatest threats to global health is cancer. Probiotic foods have been shown to have therapeutic promise in the management of cancer, even though traditional treatments such as radiation therapy, chemotherapy, and surgery are still essential. The generation of anticarcinogenic compounds, immune system stimulation, and gut microbiota regulation are a few ways that probiotics when taken in sufficient quantities, might help health. The purpose of this review is to examine the therapeutic potential of probiotic foods in the management of cancer. Research suggests that certain strains of probiotics have anticancer effects by preventing the growth of cancer cells, triggering apoptosis, and reducing angiogenesis in new tumors. Probiotics have shown promise in mitigating treatment-related adverse effects, such as diarrhea, mucositis, and immunosuppression caused by chemotherapy, improving the general quality of life for cancer patients. However, there are several factors, such as patient-specific features, cancer subtype, and probiotic strain type and dosage, which affect how effective probiotic therapies are in managing cancer. More research is necessary to find the long-term safety and efficacy characteristics of probiotics as well as to clarify the best ways to incorporate them into current cancer treatment methods.

Graphical abstract

Graphical representation showing the role of probiotic foods in cancer management.

Anticancer Potential of Postbiotic Derived from Lactobacillus brevis and Lactobacillus casei: In vitro Analysis of Breast Cancer Cell Line

Breast cancer has emerged as the most widespread and dangerous type of malignancy among women worldwide. Postbiotics have recently emerged as a promising novel adjunct in breast cancer therapy, due to their immunomodulatory effects and the potential to mitigate the adverse effects of conventional treatments. This study aims to investigate the therapeutic effects of postbiotics derived from Lactobacillus brevis (CSF2) and Lactobacillus casei (CFS5), specifically examining their ability to inhibit cell proliferation and induce apoptosis in MCF-7 breast cancer cells. In the current study, the anticancer activity of the cell-free supernatant of L. brevis and L. casei was investigated against MCF-7 cells using MTT assay, flow cytometry, and qRT-PCR technique. Both bacteria showed a high potential for the induction of cell death in MCF-7 cells. However, CFS2 cytotoxicity was significantly higher than CFS5. Flow cytometry results showed significant induction of early apoptosis in cells treated with both CFS2 and CFS5 within 48 h. The induction was notably higher in cells treated with CFS2 compared to CFS5. Overall, CFS2 therapy resulted in a greater increase in BAX and CASP9 gene expression, as well as an elevated BAX/BCL2 ratio within 48 h. These findings indicate that the CFS2 treatment showed a higher level of apoptotic activity than the CFS5 treatment. High biocompatibility was demonstrated following treatment with CFS2 and CFS5. These CFSs may serve as adjunctive medications for suppressing the proliferation of cancer cells. The results of the current study highlight the potential of postbiotics in cancer treatment and suggest that supernatants may serve as effective agents for suppressing cancer cell growth and viability.

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.

Cytotoxic activity and apoptosis induction by supernatant of Lentilactobacillus buchneri on HT-29 colon cancer cells

Background and Objectives

Colorectal cancer (CRC) is the fourth most commonly diagnosed cancer and the third most deadly cancer in the world. According to recent experimental reports, probiotics and their derivatives protect CRC patients from treatment-related side effects. Therefore, the present study aimed to investigate the cytotoxic impact of the cell-free supernatant (CFS) of Lentilactobacillus buchneri on the HT-29 cancer cell line.

Materials and Methods

In the current study, we used the L. buchneri CFS, which was well isolated and identified in our previous investigation from traditional yogurt in the Arak region of Iran. The apoptosis induction in HT-29 cancer cells was assessed by cell cytotoxicity, flow cytometry, and qRT-PCR.

Results

L. buchneri CFS inhibited the proliferation of HT-29 cancer cells in a time- and dose-dependent manner. The apoptotic effect of CFS was further supported by the flow cytometry data, which showed that the maximum incidence of apoptosis was observed in HT-29 cancer cells treated with the IC50 concentration of CFS after 72 hours. CFS of L. buchneri also exerted the up-regulating effect on the expression of pro-apoptotic genes including BAX, CASP9, and CASP3. L. buchneri CFS at an IC50 dose induced cell cycle arrest in the G0/G1 phase in HT-29 cells.

Conclusion

This study indicates that L. buchneri CFS can prevent colorectal cancer (CRC) development in patients by inducing cancer cell apoptosis. This finding suggests that the CFS of L. buchneri could be used as a therapeutic agent for the control of CRC.

A Narrative Review on the Advance of Probiotics to Metabiotics

Recently, the term metabiotics has emerged as a new concept of probiotics. This concept entails combining existing probiotic components with metabolic by-products improve specific physiological functionalities. Representative ingredients of these metabiotics include short-chain fatty acids (SCFAs), bacteriocins, polysaccharides, and peptides. The new concept is highly regarded as it complements the side effects of existing probiotics and is safe and easy to administer. Known health functions of metabiotics are mainly immune regulation, anti-inflammatory, anticancer, and brain-neurological health. Research has been actively conducted on the health benefits related to the composition of intestinal microorganisms. Among them, the focus has been on brain neurological health, which requires extensive research. This study showed that neurological disorders, such as depression, anxiety, autism spectrum disorder, Alzheimer's disease, and Parkinson's disease, can be treated and prevented according to the gut-brain axis theory by changing the intestinal microflora. In addition, various studies are being conducted on the immunomodulatory and anticancer effects of substances related to metabiotics of the microbiome. In particular, its efficacy is expected to be confirmed through human studies on various cancers. Therefore, developing various health functional effects of the next-generation probiotics such as metabiotics to prevent or treatment of various diseases is anticipated.

The inhibition effects of Lentilactobacillus buchneri-derived membrane vesicles on AGS and HT-29 cancer cells by inducing cell apoptosis

In recent years, probiotics and their derivatives have been recognized as important therapeutic agents in the fight against cancer. Therefore, this study aimed to investigate the anticancer effects of membrane vesicles (MVs) from Lentilactobacillus buchneri strain HBUM07105 probiotic isolated from conventional and unprocessed yogurt in Arak province, Iran, against gastric and colon cancer cell lines. The MVs were prepared from the cell-free supernatant (CFS) of L. buchneri and characterized using field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) and SPS-PAGE techniques. The anticancer activity of MVs was evaluated using MTT, flow cytometry, qRT-PCR techniques, and a scratch assay. The study investigated the anti-adenocarcinoma effect of MVs isolated from L. buchneri on a human gastric adenocarcinoma cell line (AGS) and a human colorectal adenocarcinoma cell line (HT-29) at 24, 48, and 72-h time intervals. The results demonstrated that all prepared concentrations (12.5, 25, 50, 100, and 200 µg/mL) of MVs reduced the viability of both types of human adenocarcinoma cells after 24, 48, and 72 h of treatment. The analysis of the apoptosis results revealed that the percentage of AGS and HT-29 cancer cells in the early and late stages of apoptosis was significantly higher after 24, 48, and 72 h of treatment compared to the untreated cancer cells. After treating both AGS and HT-29 cells with the MVs, the cells were arrested in the G0/G1 phase. These microvesicles demonstrate apoptotic activity by increasing the expression of pro-apoptotic genes (BAX, CASP3, and CASP9). According to the scratch test, MVs can significantly decrease the migration of HT-29 and AGS cancer cells after 24, 48, and 72 h of incubation compared to the control groups. The MVs of L. buchneri can also be considered a potential option for inhibiting cancer cell activities.

Microbiota Manipulation as an Emerging Concept in Cancer Therapy

Background

The human body is colonized by billions of bacteria that provide nutrients to the host, train our immune system, and importantly affect our heath. It has long been suggested that microbes might play a role in tumor pathogenesis; however, compelling evidence was only provided in the past decades when novel detection methods that do not depend on culturing techniques had been developed.

Summary

The microbiome impacts tumor development and anti-tumor therapies on various levels. Bacteria can promote or suppress tumor growth via direct interactions with cancer cells, production of metabolites that promote or inhibit tumor growth, and via stimulation or suppression of the local and systemic immune response. Cancer patients harbor a distinct microbiome when compared to healthy controls, which could potentially be employed to detect, identify, and treat cancer. Manipulation of the microbiome either via supplementation of single strains, bacterial consortia, fecal microbiota transfer or the use of pre- and probiotics has been suggested as therapeutic approach to directly target tumor growth or to enhance the efficacy of current state-of-the-art treatment options.

Key Messages

(1) Bacteria have a tremendous impact on anti-cancer immune responses. (2) Cancer patients harbor a distinct microbiome when compared to healthy controls. (3) The microbiome seems to be cancer-type specific. (4) Exploitation of bacteria to promote anti-tumor therapy is a novel, very promising venue in cancer treatment.

Gut microbiota and its therapeutic implications in tumor microenvironment interactions

The development of cancer is not just the growth and proliferation of a single transformed cell, but its tumor microenvironment (TME) also coevolves with it, which is primarily involved in tumor initiation, development, metastasis, and therapeutic responses. Recent years, TME has been emerged as a potential target for cancer diagnosis and treatment. However, the clinical efficacy of treatments targeting the TME, especially its specific components, remains insufficient. In parallel, the gut microbiome is an essential TME component that is crucial in cancer immunotherapy. Thus, assessing and constructing frameworks between the gut microbiota and the TME can significantly enhance the exploration of effective treatment strategies for various tumors. In this review the role of the gut microbiota in human cancers, including its function and relationship with various tumors was summarized. In addition, the interaction between the gut microbiota and the TME as well as its potential applications in cancer therapeutics was described. Furthermore, it was summarized that fecal microbiota transplantation, dietary adjustments, and synthetic biology to introduce gut microbiota-based medical technologies for cancer treatment. This review provides a comprehensive summary for uncovering the mechanism underlying the effects of the gut microbiota on the TME and lays a foundation for the development of personalized medicine in further studies.

Probing the Potential: Exploring Probiotics as a Novel Frontier in Cancer Prevention and Therapeutics

Cancer has emerged as one of the most prevalent diseases worldwide, with a consistent rise in the number of cases observed over the past few decades. The rising mortality rates associated with cancer have transformed it into a significant global challenge. Despite the presence of various anti-cancer drugs, the complete eradication of cancer remains an elusive goal. The numerous undesirable effects associated with cancer therapy further emphasize the importance of developing an alternative technique of cancer treatment. Recent research has established the beneficial effects of a probiotic diet or supplementation against cancer without displaying any detrimental consequences. An alteration in the gut microbiome balance in humans can result in the development of various diseases, including cancer. Probiotics play a pivotal role in restoring the balance of gut flora, potentially contributing to cancer prevention. Furthermore, they have the capacity to curb the invasion and dissemination of infections that carry the risk of triggering cancer. Probiotics can combat cancer in various ways, such as by eliciting and boosting the immune response, secreting metabolites, preventing cancer cells from metastasizing, inhibiting carcinogenic chemicals, and mitigating their toxicity, etc. The present review intends to outline the significance of probiotics and their underlying mechanisms in combating various cancer types. Additionally, this review highlights the benefits of probiotic use in pre- and post-operative cancer patients.

Human anaerobic microbiome: a promising and innovative tool in cancer prevention and treatment by targeting pyruvate metabolism

INTRODUCTION

Even in present-day times, cancer is one of the most fatal diseases. People are overwhelmed by pricey chemotherapy, immunotherapy, and other costly cancer therapies in poor and middle-income countries. Cancer cells grow under anaerobic and hypoxic conditions. Pyruvate is the final product of the anaerobic glycolysis pathway, and many cancer cells utilize pyruvate for their growth and development. The anaerobic microbiome produces many anti-cancer substances that can act as anti-tumor agents and are both feasible and of low cost. There are different mechanisms of action of the anaerobic microbiome, such as the production of short-chain fatty acids (SCFAs), and competition for the anaerobic environment includes the metabolic product pyruvate to form lactic acid for energy.

KEY FINDINGS

In this review, we have summarized the role of the metabolic approach of the anaerobic human microbiome in cancer prevention and treatment by interfering with cancer metabolite pyruvate. SCFAs possess decisive outcomes in condoning almost all the hallmarks of cancer and helping the spread of cancer to other body parts. Studies have demonstrated the impact and significance of using SCFA, which results from anaerobic bacteria, as an anti-cancer agent. Anaerobic bacteria-based cancer therapy has become a promising approach to treat cancer using obligate and facultative anaerobic bacteria because of their ability to penetrate and increase in an acidic hypoxic environment.

SIGNIFICANCE

This review attempts to provide the interconnection of cancer metabolism and anaerobic microbiome metabolism with a focus on pyruvate metabolism to understand and design unique anaerobic microbiota-based therapy for cancer patients.

The Potential of Meta-Proteomics and Artificial Intelligence to Establish the Next Generation of Probiotics for Personalized Healthcare

The symbiosis of probiotic bacteria with humans has rendered various health benefits while providing nutrition and a suitable environment for their survival. However, the probiotics must survive unfavorable gut conditions to exert beneficial effects. The intrinsic resistance of probiotics to survive harsh conditions results from a myriad of proteins. Interaction of microbial proteins with the host is indispensable for modulating the gut microbiome, such as interaction with cell receptors and protective action against pathogens. The complex interplay of proteins should be unraveled by utilizing metaproteomic strategies. The contribution of probiotics to health is now widely accepted. However, due to the inconsistency of generalized probiotics, contemporary research toward precision probiotics has gained momentum for customized treatment. This review explores the application of metaproteomics and AI/ML algorithms in resolving multiomics data analysis and in silico prediction of microbial features for screening specific beneficial probiotic organisms. Implementing these integrative strategies could augment the potential of precision probiotics for personalized healthcare.

Lysates from the probiotic bacterium Streptococcus thermophilus enhances the survival of T cells and triggers programmed cell death in neuroblastoma cells

Neuroblastoma is the most common brain solid tumor in infancy. Despite the availability of numerous approaches like immunotherapy, surgery, chemotherapy, and radiotherapy, neuroblastoma frequently develops resistance and recurs. Immunotherapy is one of the most promising approaches and PD-L1 antibody blocking is the phenomena used to inhibit PD-1 receptors to increase and improve cytotoxic T cells toward cancer. Numerous studies underlined the critical role of probiotics on immune system development and modulation in addition to possible role in inducing apoptosis in cancer cells. In this study, a Streptococcus thermophilus strain, isolated from a local yogurt, was used as it is considered a potential probiotic due to its tolerance lower pH, bile acid, antibiotic suitability, and blood hemolysis. Our results showed that S. thermophilus lysates played as an immune checkpoint modulator at 25 µg/ml dose boosting PD-L1 transcripts and protein levels in SH-SY5Y neuroblastoma cell line. Interestingly, co-culture between SH-SY5Y and Jurkat T cells in the presence of blocking PD-L1 antibodies increased Jurkat T-cell viability compering to control without lysate. On the other hand, annexin-V/7-AAD, qPCR and western blot results showed that S. thermophilus lysates at 200 and 400 µg/ml decreased SH-SY5Y cell viability and increased apoptotic marker genes transcription and caspase-3 and caspase-9 protein expression.

Anticancer assessment and antibiofilm potential of Laetiporus sulphureus mushroom originated from Serbia

Laetiporus sulphureus (Bull.) Murrill is a well-known edible mushroom consumed in nutrition as delicacy. It has been used in traditional medicine because of its beneficial effects on human wellness, such as antimicrobial, antioxidant, and anticancer potential. The present study determined the phenolic profile of Laetiporus sulphureus ethanolic extract (LSE) by high-performance liquid chromatographic method. Tolerance of two probiotic bacterial strains Lactiplantibacillus plantarum 229v, Bifidobacterium animalis subsp. lactis and probiotic yeast Saccharomyces boulardii on LSE was analyzed in terms of viability and biofilm formation. Effects of extract on colorectal (HCT-116) and cervical (HeLa) cancer cells viability was determined using MTT test in concentration range: 1-500 μg/mL after 24 and 72 h. Redox parameters (superoxide anion radicals, nitrites, and reduced glutathione) were evaluated using NBT, Griess, and GSH assays in the concentration range of 1-500 μg/mL after 24 and 72 h. Antimigratory activity was determined by wound healing method using selected concentrations of 10 and 50 μg/mL after 24 h. Untreated cells were considered as control. As control cell line, we used healthy fibroblasts (MRC-5). Our results demonstrated abundance of LSE in phenolics, with rosmarinic acid as the main component. LSE induced low tolerance of tested planktonic probiotic strains, with no affection on their ability to form biofilm. No significant cytotoxicity on tested cancer cells was observed, with prooxidative and antimigratory effects noticed. Extract exerted significant antimigratory activity on cancer cells without effect on planktonic and probiotic cultures in biofilm. These results indicate potential application of Laetiporus sulphureus ethanolic extract as natural protector of probiotics with prominent ability to suppress cancer cell motility.

Recent insights into the nutritional immunomodulation of cancer-related microRNAs

Cancer is the most common cause of death worldwide, following cardiovascular diseases. Cancer is a multifactorial disease and many reasons such as physical, chemical, biological, and lifestyle-related factors. Nutrition, which is one of the various factors that play a role in the prevention, development, and treatment of many types of cancer, affects the immune system, which is characterized by disproportionate pro-inflammatory signaling in cancer. Studies investigating the molecular mechanisms of this effect have shown that foods rich in bioactive compounds, such as green tea, olive oil, turmeric, and soybean play a significant role in positively changing the expression of miRNAs involved in the regulation of genes associated with oncogenic/tumor-suppressing pathways. In addition to these foods, some diet models may change the expression of specific cancer-related miRNAs in different ways. While Mediterranean diet has been associated with anticancer effects, a high-fat diet, and a methyl-restricted diet are considered to have negative effects. This review aims to discuss the effects of specific foods called "immune foods," diet models, and bioactive components on cancer by changing the expression of miRNAs in the prevention and treatment of cancer.

Oral Lactobacillus species and their probiotic capabilities in patients with periodontitis and periodontally healthy individuals

OBJECTIVES

This study aimed to identify oral Lactobacillus species and characterize their adhesion properties and antibacterial activity in patients with periodontitis compared with periodontally healthy individuals.

MATERIALS AND METHODS

Three hundred and fifty-four isolates from the saliva, subgingival, and tongue plaque of 59 periodontitis patients and 59 healthy individuals were analyzed. Oral Lactobacillus species were identified through the culture method in the modified MRS medium and confirmed by molecular testing. Moreover, the radial diffusion assay and cell culture methods were used to determine the antibacterial activities of oral strains against oral pathogens and their adhesion activity in vitro.

RESULTS

67.7% of the cases and 75.7% of the control samples were positive for the Lactobacillus species. Lacticaseibacillus paracasei and Limosilactobacillus fermentum were the dominant species in the case group, whereas Lacticaseibacillus casei and Lactiplantibacillus plantarum were dominant in the control group. Lactobacillus crispatus and Lactobacillus gasseri had higher antibacterial effects against oral pathogens. Moreover, Ligilactobacillus salivarius and L. fermentum demonstrated the highest ability to adhere to oral mucosal cells and salivary-coated hydroxyapatite.

CONCLUSION

L. crispatus, L. gasseri, L. fermentum, and L. salivarius can be introduced as probiotic candidates since they demonstrated appropriate adherence to oral mucosal cells and salivary-coated hydroxyapatite and also antibacterial activities. However, further studies should be conducted to assess the safety of probiotic interventions using these strains in patients with periodontal disease.

Assessing the probiotic potential, antioxidant, and antibacterial activities of oat and soy milk fermented with Lactiplantibacillus plantarum strains isolated from Tibetan Kefir

Sufficient intake of probiotics has been shown to help in the digestion, protect the body against pathogenic microorganisms and boost the immune system. Recently, due to high prevalence of milk allergies and lactose intolerance in population, the non-dairy based probiotic alternative are becoming increasing popular. In this context, the oat milk and soya milk-based fermented products can be an ideal alternative for the development of Lactic acid bacteria bacteria based probiotics. These bacteria can not only improve the product's flavor and bioavailability but also increases its antibacterial and antioxidant capabilities due to fermentation process. The purpose of the resent work was to assess the antioxidant and probiotic properties of oat and soy milk that had been fermented with three different strains of Lactiplantibacillus plantarum (L. plantarum) including L. plantarum 12-3, L. plantarum K25, and L. plantarum YW11 isolated from Tibetan Kefir. Different validated assays were used to evaluate the probiotic properties, adhesion and survival in the digestive system (stomach, acid and bile salts resistance), antioxidant and antimicrobial activities and safety (ABTS and DPPH scavenging assays) of these strains. Results of the study showed that soya milk and oat milk fermented with L. plantarum strains possess promising probiotic, antibacterial and antioxidant properties. These results can be helpful to produce dairy-free probiotic replacements, which are beneficial for those who are unable to consume dairy products due to dietary or allergic restrictions.

Prevalence and influencing factors of probiotic usage among colorectal cancer patients in China: A national database study

Probiotics have become increasingly popular among cancer patients. However, there is limited data from a real-world setting. This study aims to conduct a retrospective analysis to understand the trend of probiotic prescriptions in Chinese colorectal cancer patients. The Mann-Kendall and Cochran-Armitage trend test was applied to estimate the trend significance. Gephi software identified the combination of probiotic strains. The binary logistic regression investigated influence factors, and Spearman's rank correlation coefficient calculated correlations between probiotics and antitumor drug usage. The probiotic prescription percentage increased from 3.3% in 2015 to 4.2% in 2021 (Z = 12.77, p < 0.001). Although 48.3% of probiotic prescriptions had no indication-related diagnosis, diarrhea (OR 10.91, 95% CI 10.57-11.26) and dyspepsia (3.97, 3.82-4.12) included prescriptions most likely to contain probiotics. Prescriptions from the tertiary hospital (1.43,1.36-1.50), clinics (1.30, 1.28-1.33), and senior patients (1.018 per year, 1.017-1.019) were more likely to contain probiotics. Most probiotic prescriptions (95.0%) contained one probiotic product but multiple strains (69.3%). Enterococcus faecalis (49.7%), Lactobacillus acidophilus (39.4%), and Clostridium butyricum (27.9%) were the most prescribed strains. The probiotics co-prescribed with antitumor agents increased rapidly from 6.6% to 13.8% in seven years (Z = 15.31, p < 0.001). Oral fluorouracil agents (2.35, 2.14-2.59), regorafenib (1.70,1.27-2.26), and irinotecan (1.27,1.15-1.41) had a higher probability to co-prescribed with probiotics. There was no correlation between probiotic strain selection and specific antitumor drug use. The increasing prescription of probiotics in colorectal cancer patients in China may be related to treating the gastrointestinal toxicity of anti-cancer drugs. With unapproved indications and a lack of strain selectivity, evidence-based guidelines are urgently needed to improve probiotic use in this population.

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.

Bacillus subtilis supernatant improves the efficacy of radiation therapy in rat intestinal epithelial cells by upregulation of bax and caspase-3 genes

BACKGROUND

Colorectal Cancer (CC) is among the most prevalent cancers in elderly persons. Radiotherapy is usually prescribed as CC develops, however, radiation beams indiscriminately affect normal cells. Previous studies nominated that probiotics and their metabolites can be used to minimize the side effects of radiotherapy. Hereby, the aim of this study was to investigate the probable correlation between cell-free supernatant of Bacillus subtilis and radiation response in normal and cancerous cell lines.

METHODS AND RESULTS

IEC-18 and SW-48 cells were treated with different concentrations of B. subtilis supernatant. To evaluate the effect of probiotic treatments under radiation and the normal situation, the cytotoxicity of the treatments was measured using the MTT method. The cell cycle status was analyzed by flow cytometry. The expression levels of Bax, Bcl-2, and Caspase 3 genes were also determined by real-time (RT) PCR. B. subtilis supernatant increased the viability of normal cells under radiation treatment, although this effect was not significant. 40% v/v of this mixture could amplify the lethal effect of radiation and decreased the viability of cancer cells. SW-48 cells that received 40% v/v of the supernatant had a significantly higher rate of apoptosis. Probiotic supernatant effectively induced the expression of proapoptotic Bax and Caspase 3 genes.

CONCLUSION

Presented results confirmed that the supernatant of B. subtilis can be supposed as a clue to improve the efficacy of radiation therapy in CC patients as it increased the sensitivity of cancerous cells and protected normal epithelial cells from detrimental effects of radiation.

Lactiplantibacillus plantarum P101 Attenuated Cyclophosphamide-Induced Liver Injury in Mice by Regulating the Nrf2/ARE Signaling Pathway

Cyclophosphamide causes side effects in cancer patients, including hepatotoxicity. Probiotics have recently emerged as potential approaches for the administration of many diseases. This study aimed to evaluate the protective effects of Lactiplantibacillus plantarum P101 against cyclophosphamide-induced liver injury and elucidate the underlying mechanism. In this study, Lactiplantibacillus plantarum P101 or Lactobacillus rhamnosus GG were pre-administered to mice with varying duration (1 week, 2 weeks, and 3 weeks) before being intraperitoneally injected with cyclophosphamide at a dose of 30 mg/kg/day for 7 days to induce liver injury. Results demonstrated that cyclophosphamide-induced liver injury was characterized by histopathological disorders, including irregular central venous shape and hepatic vascular rupture, as well as a severe inflammation response and oxidative stress. The administration of probiotics for 3 weeks exerted the most significant improvements in alleviating liver injury, oxidative stress, and inflammation when compared to the shorter intervention duration. Notably, Lactiplantibacillus plantarum P101 exhibited more pronounced effects than Lactobacillus rhamnosus GG. Furthermore, Lactiplantibacillus plantarum P101 enhanced the antioxidant defense system by activating the Nrf2/ARE signaling pathway, ultimately alleviating hepatotoxicity and hepatocyte apoptosis. In conclusion, this study highlighted the potential of Lactiplantibacillus plantarum P101 to alleviate cyclophosphamide-induced hepatotoxicity.

Probiotic-Derived Bioactive Compounds in Colorectal Cancer Treatment

Colorectal cancer (CRC) is a multifactorial disease with increased morbidity and mortality rates globally. Despite advanced chemotherapeutic approaches for the treatment of CRC, low survival rates due to the regular occurrence of drug resistance and deleterious side effects render the need for alternative anticancer agents imperative. Accumulating evidence supports that gut microbiota imbalance precedes the establishment of carcinogenesis, subsequently contributing to cancer progression and response to anticancer therapy. Manipulation of the gut microbiota composition via the administration of probiotic-derived bioactive compounds has gradually attained the interest of scientific communities as a novel therapeutic strategy for CRC. These compounds encompass miscellaneous metabolic secreted products of probiotics, including bacteriocins, short-chain fatty acids (SCFAs), lactate, exopolysaccharides (EPSs), biosurfactants, and bacterial peptides, with profound anti-inflammatory and antiproliferative properties. This review provides a classification of postbiotic types and a comprehensive summary of the current state of research on their biological role against CRC. It also describes how their intricate interaction with the gut microbiota regulates the proper function of the intestinal barrier, thus eliminating gut dysbiosis and CRC development. Finally, it discusses the future perspectives in precision-medicine approaches as well as the challenges of their synthesis and optimization of administration in clinical studies.

Impact of Fermentation Conditions on Physicochemical Properties, Antioxidant Activity, and Sensory Properties of Apple-Tomato Pulp

The aim of the study was to optimize the conditions [inoculum size (4, 6, and 8%), fermentation temperature (31, 34, and 37 °C), and apple: tomato ratio (2:1, 1:1, and 1:2)] on the viable cell count and sensory evaluation in apple-tomato pulp by response surface methodology (RSM), and determine the physicochemical properties, antioxidant activity, and sensory properties during fermentation. The optimal treatment parameters obtained were an inoculum size of 6.5%, a temperature of 34.5 °C, and an apple: tomato ratio of 1:1. After fermentation, the viable cell count reached 9.02 lg(CFU/mL), and the sensory evaluation score was 32.50. During the fermentation period, the pH value, total sugar, and reducing sugar decreased by 16.67%, 17.15%, and 36.05%, respectively. However, the total titratable acid (TTA), viable cell count, total phenol content (TPC), and total flavone content (TFC) increased significantly by 13.64%, 9.04%, 21.28%, and 22.22%, respectively. The antioxidant activity [2,2-diphenyl-1-picrylhydrazyl (DPPH) free-radical scavenging ability, 2,2'-azino-di(2-ethyl-benzthiazoline-sulfonic acid-6) ammonium salt (ABTS) free-radical scavenging ability, and ferric-reducing antioxidant capacity power (FRAP)] also increased by 40.91%, 22.60%, and 3.65%, respectively, during fermentation. A total of 55 volatile flavour compounds were detected using HS-SPME-GC-MS among the uninoculated samples and fermented samples before and after fermentation. The results showed that fermentation increased the types and total amount of volatile components in apple-tomato pulp, and eight new alcohols and seven new esters were formed. Alcohols, esters, and acids were the main volatile components in apple-tomato pulp, accounting for 57.39%, 10.27%, and 7.40% of the total volatile substances, respectively.

The Anti-Adhesion Effect of Nisin as a Robust Lantibiotic on the Colorectal Cancer Cells

Background

Bacteriocins are a type of antimicrobial peptide that are produced by probiotics. They have been studied as possible therapeutic drugs and have been used to suppress bacterial development in foods. Nisin is a potent bacteriocin having the anti-microbial and anti-cancer characteristics produced by Lactococcus lactis. The aim of the present paper is to evaluate the influence of Nisin on cell adhesion and its two related genes, mmp-2 and mmp-9, in the colorectal cancer cell line.

Materials and Methods

For this purpose, HT-29 cells were treated with various concentrations of Nisin and the cell cytotoxicity, cell adhesion, and gene expression were evaluated using the MTT assay, cell adhesion assay, and real-time PCR.

Results

Our findings showed that 32 to 1024 μg/ml of Nisin resulted in a significant reduction in cell viability (P < 0.05). Furthermore, 128 and 256 μg/ml of Nisin significantly reduced the cell adhesion, and mmp-2 and mmp-9 gene expressions (P < 0.05).

Conclusion

Our findings suggested that Nisin could prevent metastasis and cancer progression.

Role of Probiotics in the Prevention and Treatment of GIT Cancers: Updated Review

Cancer, one of the leading causes of death worldwide, has been the subject of extensive study by many researchers. Cancer is affected by both genetic and immune system factors in the human body. The gut microbiota plays an important role in the body's capacity to maintain homeostasis. Because of their beneficial effects on human health and their ability to successfully prevent and treat various chronic diseases, such as cancer, probiotics are becoming increasingly important in medicine. A wealth of research has shown that probiotic consumption can significantly helpful in cancer prevention and treatment. The goal of this review is to provide a thorough overview of the research on the function of probiotic bacteria in the prevention and treatment of gastrointestinal cancers.

The Role of Genetically Engineered Probiotics for Treatment of Inflammatory Bowel Disease: A Systematic Review

BACKGROUND

Many preclinical studies have demonstrated the effectiveness of genetically modified probiotics (gm probiotics) in animal models of inflammatory bowel disease (IBD).

OBJECTIVE

This systematic review was performed to investigate the role of gm probiotics in treating IBD and to clarify the involved mechanisms.

METHODS

PubMed, Web of Science, Cochrane Library, and Medline were searched from their inception to 18 September 2022 to identify preclinical and clinical studies exploring the efficacy of gm probiotics in IBD animal models or IBD patients. Two independent researchers extracted data from the included studies, and the data were pooled by the type of study; that is, preclinical or clinical.

RESULTS

Forty-five preclinical studies were included. In these studies, sodium dextran sulfate and trinitrobenzene sulfonic acid were used to induce colitis. Eleven probiotic species have been genetically modified to produce therapeutic substances, including IL-10, antimicrobial peptides, antioxidant enzymes, and short-chain fatty acids, with potential therapeutic properties against colitis. The results showed generally positive effects of gm probiotics in reducing disease activity and ameliorating intestinal damage in IBD models; however, the efficacy of gm probiotics compared to that of wild-type probiotics in many studies was unclear. The main mechanisms identified include modulation of the diversity and composition of the gut microbiota, production of regulatory metabolites by beneficial bacteria, reduction of the pro- to anti-inflammatory cytokine ratio in colonic tissue and plasma, modulation of oxidative stress activity in the colon, and improvement of intestinal barrier integrity. Moreover, only one clinical trial with 10 patients with Crohn's disease was included, which showed that L. lactis producing IL-10 was safe, and a decrease in disease activity was observed in these patients.

CONCLUSIONS

Gm probiotics have a certain efficacy in colitis models through several mechanisms. However, given the scarcity of clinical trials, it is important for researchers to pay more attention to gm probiotics that are more effective and safer than wild-type probiotics to facilitate further clinical translation.

Probiotic Supplementation Attenuates Chemotherapy-Induced Intestinal Mucositis in an Experimental Colorectal Cancer Liver Metastasis Rat Model

The use of chemotherapeutic agents is of paramount importance when treating colorectal cancer (CRC). Unfortunately, one of the most frequent chemotherapy (CTx) side effects is intestinal mucositis (IM), which may present with several clinical symptoms such as nausea, bloating, vomiting, pain, and diarrhea and even can result in life-threatening complications. There is a focused scientific effort towards developing new therapies to prevent and treat IM. The aim of this study was to assess the outcomes of probiotic supplementation on CTx-induced IM in a CRC liver metastasis rat model. Six-week-old male Wistar rats received either a multispecies probiotic or placebo mixture. On the 28th experiment day, rats received FOLFOX CTx, and afterwards, the severity of diarrhea was evaluated twice daily. Stool samples were collected for further microbiome analysis. Additionally, immunohistochemical stainings of ileum and colon samples with were performed with MPO, Ki67, and Caspase-3 antibodies. Probiotic supplementation alleviates the severity and length of CTx-induced diarrhea. Additionally, probiotics significantly reduced FOLFOX-induced weight and blood albumin loss. Furthermore, probiotic supplementation mitigated CTx-induced histological changes in the gut and promoted intestinal cell regeneration. This study shows that multispecies probiotic supplementation attenuates FOLFOX-induced IM symptoms by inhibiting apoptosis and promoting intestinal cell proliferation.

Effect of Probiotics in Breast Cancer: A Systematic Review and Meta-Analysis

Probiotics may have the potential to protect against breast cancer, partly through systemic immunomodulatory action and active impact upon intestinal microbiota. Given a few clinical studies on their curative role, we conducted a systematic review of the potential effects of probiotics in breast cancer patients and survivors of breast cancer, aiming to support further clinical studies. A literature search was performed using PubMed, Embase, and the CENTRAL databases from inception through to March 2022. A total of eight randomized clinical trials were identified from thirteen articles published between 2004 and 2022. We evaluated quality-of-life measures, observed bacterial species and diversity indices, probiotic-related metabolites, inflammatory biomarkers, and other responses in breast cancer patients and survivors. Results were synthesized qualitatively and quantitatively using random-effects meta-analysis. Different probiotics supplements utilized included Lactobacillus species alone (Lacto), with or without estriol; probiotic combinations of Lactobacillus with Bifidobacterium (ProLB), with or without prebiotic fructooligosaccharides (FOS); ProLB plus Streptococcus and FOS (ProLBS + FOS); and ProLB plus Enterococcus (ProLBE). We found that use of ProLBS with FOS in breast cancer patients and use of ProLBE in survivors of breast cancer show potential benefits in countering obesity and dyslipidemia. ProLBS with FOS use decreases pro-inflammatory TNF-α in breast cancer survivors and improves quality of life in those with breast-cancer-associated lymphedema. Supplementing probiotics capsules (10⁹ CFU) with a prebiotic and using an intake duration of 10 weeks could provide a better approach than probiotics alone.

Exploring Mushroom Polysaccharides for the Development of Novel Prebiotics: A Review

Prebiotics have gained much attention in recent years as functional food ingredients. This has encouraged researchers to look for sustainable alternative sources of prebiotics. Prebiotics help in the modulation of the human intestinal microbiota and thereby improve host health. Chicory, asparagus, and Jerusalem artichoke are some conventional prebiotics that have been extensively studied. Mushrooms are rich sources of medicinal foods as well as bioactive polysaccharides and essential amino acids. They contain large amounts of chitin, mannans, galactans, xylans, glucans, krestin, lentinan, and hemicellulose, thus making it a potential candidate for prebiotics. They are also rich sources of fibers, proteins, and antioxidants. Several mushroom species like Ganoderma lucidum, Pleurotus ostreatus, Hericium erinaceus, Agaricus bisporus, and Lentinula edodes are rich in medicinal properties that have an array of applications. These medicinal mushrooms can be repurposed to regulate gut microbiota. In this review, we discuss the prebiotic effects of different mushroom species on probiotic organisms. We also reviewed the potential of mushroom waste as novel, cheap, and alternative sources of prebiotics.

Endotoxemia and Gastrointestinal Cancers: Insight into the Mechanisms Underlying a Dangerous Relationship

Lipopolysaccharide (LPS), also known as endotoxin, is a component of the membrane of gram-negative bacteria and a well-recognized marker of sepsis. In case of disruption of the intestinal barrier, as occurs with unhealthy diets, alcohol consumption, or during chronic diseases, the microbiota residing in the gastrointestinal tract becomes a crucial factor in amplifying the systemic inflammatory response. Indeed, the translocation of LPS into the bloodstream and its interaction with toll-like receptors (TLRs) triggers molecular pathways involved in cytokine release and immune dysregulation. This is a critical step in the exacerbation of many diseases, including metabolic disorders and cancer. Indeed, the role of LPS in cancer development is widely recognized, and examples include gastric tumor related to Helicobacter pylori infection and hepatocellular carcinoma, both of which are preceded by a prolonged inflammatory injury; in addition, the risk of recurrence and development of metastasis appears to be associated with endotoxemia. Here, we review the mechanisms that link the promotion and progression of tumorigenesis with endotoxemia, and the possible therapeutic interventions that can be deployed to counteract these events.

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.

The role of the gut microbiota and probiotics associated with microbial metabolisms in cancer prevention and therapy

Cancer is the second leading cause of elevated mortality worldwide. Thus, the development of drugs and treatments is needed to enhance the survival rate of the cancer-affected population. Recently, gut microbiota research in the healthy development of the human body has garnered widespread attention. Many reports indicate that changes in the gut microbiota are strongly associated with chronic inflammation-related diseases, including colitis, liver disease, and cancer within the intestine and the extraintestinal tract. Different gut bacteria are vital in the occurrence and development of tumors within the gut and extraintestinal tract. The human gut microbiome has significant implications for human physiology, including metabolism, nutrient absorption, and immune function. Moreover, diet and lifestyle habits are involved in the evolution of the human microbiome throughout the lifetime of the host and are involved in drug metabolism. Probiotics are a functional food with a protective role in cancer development in animal models. Probiotics alter the gut microbiota in the host; thus, beneficial bacterial activity is stimulated, and detrimental activity is inhibited. Clinical applications have revealed that some probiotic strains could reduce the occurrence of postoperative inflammation among cancer patients. An association network was constructed by analyzing the previous literature to explore the role of probiotics from the anti-tumor perspective. Therefore, it provides direction and insights for research on tumor treatment.

Postbiotics versus probiotics in early-onset colorectal cancer

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

Roles of Gut Microbiome in Bone Homeostasis and Its Relationship with Bone-Related Diseases

The extended microbial genome-the gut microbiome (GM)-plays a significant role in host health and disease. It is able to influence a number of physiological functions. During dysbiosis, GM is associated with the development of various chronic diseases with impaired bone quality. In general, GM is important for bone homeostasis and can affect it via several mechanisms. This review describes the roles of GM in bone homeostasis through influencing the immune and endocrine functions, short-chain fatty acids production, calcium absorption and the gut-brain axis. The relationship between GM composition and several bone-related diseases, specifically osteoporosis, osteoarthritis, rheumatoid arthritis, diabetes mellitus, obesity and bone cancer, is also highlighted and summarized. GM manipulation may become a future adjuvant therapy in the prevention of many chronic diseases. Therefore, the beneficial effects of probiotic therapy to improve the health status of individuals with aforementioned diseases are provided, but further studies are needed to clearly confirm its effectiveness. Recent evidence suggests that GM is responsible for direct and indirect effects on drug efficacy. Accordingly, various GM alterations and interactions related to the treatment of bone-related diseases are mentioned as well.

Two unique biological response-modifier glucans beneficially regulating gut microbiota and faecal metabolome in a non-alcoholic steatohepatitis animal model, with potential applications in human health and disease

OBJECTIVE

The gut microbiome and its metabolites are influenced by age and stress and reflect the metabolism and health of the immune system. We assessed the gut microbiota and faecal metabolome in a static animal model of non-alcoholic steatohepatitis (NASH).

DESIGN

This model was subjected to the following treatments: reverse osmosis water, AFO-202, N-163, AFO-202+N-163 and telmisartan treatment. Faecal samples were collected at 6 and 9 weeks of age. The gut microbiome was analysed using 16S ribosomal RNA sequences acquired by next-generation sequencing, and the faecal metabolome was analysed using gas chromatography-mass spectrometry.

RESULTS

Gut microbial diversity increased greatly in the AFO-202+N-163 group. Postintervention, the abundance of Firmicutes decreased, whereas that of Bacteroides increased and was the highest in the AFO-202+N-163 group. The decrease in the abundance of Enterobacteriaceae and other Firmicutes and the abundance of Turicibacter and Bilophila were the highest in the AFO-202 and N-163 groups, respectively. Lactobacillus abundance was highest in the AFO-202+N-163 group. The faecal metabolite spermidine, which is beneficial against inflammation and NASH, was significantly decreased (p=0.012) in the N-163 group. Succinic acid, which is beneficial in neurodevelopmental and neurodegenerative diseases, was increased in the AFO-202 group (p=0.06). The decrease in fructose was the highest in the N-163 group (p=0.0007). Isoleucine and Leucine decreased with statistical significance (p=0.004 and 0.012, respectively), and tryptophan also decreased (p=0.99), whereas ornithine, which is beneficial against chronic immune-metabolic-inflammatory pathologies, increased in the AFO-202+N-163 group.

CONCLUSION

AFO-202 treatment in mice is beneficial against neurodevelopmental and neurodegenerative diseases, and has prophylactic potential against metabolic conditions. N-163 treatment exerts anti-inflammatory effects against organ fibrosis and neuroinflammation. In combination, these compounds exhibit anticancer activity.

A Combination of Two Probiotics, Lactobacillus sporogenes and Clostridium butyricum, Inhibits Colon Cancer Development: An In Vitro Study

Cancer remains a leading cause of death worldwide and, even though several advances have been made in terms of specific treatment, the late-stage detection and the associated side effects of the conventional drugs sustain the search for better treatment alternatives. Probiotics are live microorganisms that have been proven to possess numerous health benefits for human hosts, including anticancer effects. In the present study, the in vitro effect of the association of two probiotic strains (PBT), Lactobacillus sporogenes and Clostridium butyricum, were tested against colon (HT-29 and HCT 116), lung (A549), and liver (HepG2) cancer cell lines, alone or in combination with 5-fluorouracil (5FU). Moreover, the underlying mechanism of PBT and PBT-5FU against the HT-29 cell line was evaluated using the Hoechst 33342 staining, revealing characteristic apoptotic modifications, such as chromatin condensation, nuclear fragmentation, and membrane blebbing. Furthermore, the increase in the expression of pro-apoptotic Bax, Bid, Bad, and Bak proteins and the inhibition of the anti-apoptotic Bcl-2 and Bcl-XL proteins were recorded. Collectively, these findings suggest that the two strains of probiotic bacteria, alone or in association with 5FU, induce apoptosis in colon cancer cells and may serve as a potential anticancer treatment.

The interplay between Helicobacter pylori and the gut microbiota: An emerging driver influencing the immune system homeostasis and gastric carcinogenesis

The human gut microbiota are critical for preserving the health status because they are required for digestion and nutrient acquisition, the development of the immune system, and energy metabolism. The gut microbial composition is greatly influenced by the colonization of the recalcitrant pathogen Helicobacter pylori (H. pylori) and the conventional antibiotic regimens that follow. H. pylori is considered to be the main microorganism in gastric carcinogenesis, and it appears to be required for the early stages of the process. However, a non-H. pylori microbiota profile is also suggested, primarily in the later stages of tumorigenesis. On the other hand, specific groups of gut microbes may produce beneficial byproducts such as short-chain fatty acids (acetate, butyrate, and propionate) that can modulate inflammation and tumorigenesis pathways. In this review, we aim to present how H. pylori influences the population of the gut microbiota to modify the host immunity and trigger the development of gastric carcinogenesis. We will also highlight the effect of the gut microbiota on immunotherapeutic approaches such as immune checkpoint blockade in cancer treatment to present a perspective for further development of innovative therapeutic paradigms to prevent the progression of H. pylori-induced stomach cancer.

Calorie restriction and breast cancer treatment: a mini-review

Calorie restriction (CR), referred to as a reduction in dietary calorie intake without malnutrition, has been demonstrated to be a safe way to extend longevity of yeast, worms, and laboratory animals, and to decrease the risk factors in age-related diseases including cancer in humans. Pre-clinical studies in animal models demonstrated that CR may enhance the efficacy of chemotherapy, radiation therapy, and immunotherapy during breast cancer treatment. Reduced calorie intake ameliorates risk factors and delays the onset of cancer by altering metabolism and fostering health-enhancing characteristics including increased autophagy and insulin sensitivity, and decreased blood glucose levels, inflammation, angiogenesis, and growth factor signaling. CR is not a common protocol implemented by medical practitioners to the general public due to the lack of substantial clinical studies. Future research and clinical trials are urgently needed to understand fully the biochemical basis of CR or CR mimetics to support its benefits. Here, we present a mini-review of research studies integrating CR as an adjuvant to chemotherapy, radiation therapy, or immunotherapy during breast cancer treatment.