Anticancer effects of the microbiome and its products

Cancer chemoprevention: signaling pathways and strategic approaches

Although cancer chemopreventive agents have been confirmed to effectively protect high-risk populations from cancer invasion or recurrence, only over ten drugs have been approved by the U.S. Food and Drug Administration. Therefore, screening potent cancer chemopreventive agents is crucial to reduce the constantly increasing incidence and mortality rate of cancer. Considering the lengthy prevention process, an ideal chemopreventive agent should be nontoxic, inexpensive, and oral. Natural compounds have become a natural treasure reservoir for cancer chemoprevention because of their superior ease of availability, cost-effectiveness, and safety. The benefits of natural compounds as chemopreventive agents in cancer prevention have been confirmed in various studies. In light of this, the present review is intended to fully delineate the entire scope of cancer chemoprevention, and primarily focuses on various aspects of cancer chemoprevention based on natural compounds, specifically focusing on the mechanism of action of natural compounds in cancer prevention, and discussing in detail how they exert cancer prevention effects by affecting classical signaling pathways, immune checkpoints, and gut microbiome. We also introduce novel cancer chemoprevention strategies and summarize the role of natural compounds in improving chemotherapy regimens. Furthermore, we describe strategies for discovering anticancer compounds with low abundance and high activity, revealing the broad prospects of natural compounds in drug discovery for cancer chemoprevention. Moreover, we associate cancer chemoprevention with precision medicine, and discuss the challenges encountered in cancer chemoprevention. Finally, we emphasize the transformative potential of natural compounds in advancing the field of cancer chemoprevention and their ability to introduce more effective and less toxic preventive options for oncology.

Effects of Antibiotics on First-line Immunotherapy in Patients With Recurrent or Metastatic Nasopharyngeal Carcinoma

Immunotherapy combined with chemotherapy has become the first-line treatment for recurrent or metastatic nasopharyngeal carcinoma (RM-NPC). However, the impact of antibiotic (ATB) use on the efficacy of immunotherapy in RM-NPC remains unclear. A total of 200 patients with RM-NPC who started first-line immunotherapy between October 2021 and September 2023 were included. Forty-six patients received ATB within 60 days before and 42 days after the first infusion of immunotherapy (group ATB+), and the remaining 154 patients were in group ATB-. The median progression-free survival (PFS) times of the ATB+ and ATB- groups were 11.20 and 19.87 months, respectively (P = 0.061). The 2-year overall survival (OS) rates of the ATB+ and ATB- groups were 52.6% and 76.7%, respectively (P = 0.001). In multivariate analysis, ATB use was significantly associated with worse OS (hazard ratio = 2.549, P = 0.002). No significant differences were observed between the 2 groups in terms of grade 3+ treatment-related adverse events. ATB use in RM-NPC may reduce the effectiveness of first-line immunotherapy.

Diet shapes and maintains the personalized native gut microbiomes in mice

BACKGROUND

The gut microbiome plays a critical role in human health and disease. Different dietary backgrounds play an important role in the uniqueness and diversity of the gut microbiota in different individuals, which promotes heterogeneity in disease phenotypes and treatment responses. Here, we explored how diet affects the composition and function of the native gut microbiome of model mice, based on the shotgun metagenomic and metabolomic, by analyzing the gut microbiome of C57B/6J mice in different dietary backgrounds.

RESULTS

The gut microbiomes of mice receiving different diets consistently exhibit distinct compositions across bacterial species, strains, fungi and phages. This implies that native microbial communities cannot 'homogenize' rapidly becaise of priority effects and unchanging diets. Notably, hotspot bacteria such as Limosilactobacillus reuteri, Parabacteroides distasonis and Akkermansia muciniphila were significantly different among the groups. These species harbor diverse adaptive mutations, reflecting genomic evolutionary diversity. The functional profiles of the gut microbiota also exhibit selective differences, involving the capacity for carbohydrate, branched-chain amino acid and fatty acid synthesis, as well as virulence factors, carbohydrate-active enzymes and antibiotic resistance. Furthermore, the differences in the gut microbiota also propagate to the host's serum, where structural and specific metabolite differences were observed. Metabolites that directly impact host health, such as d-glucosamine 6-phosphate and testolic acid, also show significant differences between the different dietary groups.

CONCLUSION

Our findings underscore the profound influence of different dietary the composition and functionality of the gut microbiome, offering valuable insights into optimizing health outcomes through personalized nutritional interventions. © 2024 Society of Chemical Industry.

Tumor cells that resist neutrophil anticancer cytotoxicity acquire a prometastatic and innate immune escape phenotype

In the tumor host, neutrophils may exhibit protumor or antitumor activity. It is hypothesized that in response to host-derived or therapy-induced factors, neutrophils adopt diverse functional states to ultimately execute these differential functions. Here, we provide an alternative scenario in which the response of an individual tumor cell population determines the overall protumor versus antitumor outcome of neutrophil‒tumor interactions. Experimentally, we show that human neutrophils, which are sequentially stimulated with bacteria and secreted factors from tumor cells, kill a certain proportion of tumor target cells. However, the majority of the tumor cells remained resistant to this neutrophil-mediated killing and underwent a functional, phenotypic and transcriptomic switch that was reminiscent of partial epithelial‒to-mesenchymal transition. This cell biological switch was associated with physical escape from NK-mediated killing and resulted in enhanced metastasis to the lymph nodes in a preclinical orthotopic mouse model. Mechanistically, we identified the antimicrobial neutrophil granule proteins neutrophil elastase (NE) and matrix metalloprotease-9 (MMP-9) as the molecular mediators of this functional switch. We validated these data in patients with head and neck cancer and identified bacterially colonized intratumoral niches that were enriched for mesenchymal tumor cells and neutrophils expressing NE and MMP-9. Our data reveal the parallel execution of tumor cytotoxic and prometastatic activity by activated neutrophils and identify NE and MMP-9 as mediators of lymph node metastasis. The identified mechanism explains the functional dichotomy of tumor-associated neutrophils at the level of the tumor target cell response and has implications for superinfected cancers and the dysbiotic tumor microenvironment.

Pseudomonas aeruginosa enhances anti-PD-1 efficacy in colorectal cancer by activating cytotoxic CD8+ T cells

Background

Immune checkpoint therapy for colorectal cancer (CRC) has been found to be unsatisfactory for clinical treatment. Fecal microbiota transplantation (FMT) has been shown to remodel the intestinal flora, which may improve the therapeutic effect of αPD-1. Further exploration of key genera that can sensitize cells to αPD-1 for CRC treatment and preliminary exploration of immunological mechanisms may provide effective guidance for the clinical treatment of CRC.

Methods

In this study, 16S rRNA gene sequencing was analyzed in the fecal flora of both responders and no-responders to αPD-1 treatment, and the therapeutic effect was experimentally verified.

Results

Pseudomonas aeruginosa was found to be highly abundant in the fecal flora of treated mice, and Pseudomonas aeruginosa mannose-sensitive hemagglutinin (PA-MSHA) in combination with αPD-1 was effective in the treatment of CRC through the induction of CD8+ T-cell immunological effects.

Conclusion

The clinical drug PA-MSHA can be used in combination with αPD-1 for the treatment of CRC as a potential clinical therapeutic option.

Streptococcus anginosus promotes gastric cancer progression via GSDME-mediated pyroptosis pathway: Molecular mechanisms of action of GSDME, cleaved caspase-3, and NLRP3 proteins

Streptococcus vasculosus is a common oral and intestinal symbiotic bacteria, but it can transform into a pathogen under certain conditions, affecting the host's immune response. Studies have shown that Streptococcus vasculosus may promote tumor growth and metastasis by activating host inflammatory responses. This study simulated the environment of Streptococcus vascularis infection through in vitro cell culture experiment, and observed the influence of streptococcus vascularis at different time points and different concentrations on cancer cells. The expression and activity of GSDME, cleaved caspase-3 and NLRP3 proteins were detected by Western blot, immunofluorescence and flow cytometry. By constructing gene knockout and overexpression cell models, the role of these protein molecules in promoting cancer progression of Streptococcus vascularis was further verified. It was found that GSDME activation is a key step in Pyroptosis occurrence, and cleaved caspase-3 plays an important role in GSDME cleavage activation. The activation of NLRP3 inflammatome is closely related to the inflammatory response induced by Streptococcus vasculosus, and thus affects the tumor microenvironment.

Microbiota-Derived L-SeMet Potentiates CD8+ T Cell Effector Functions and Facilitates Anti-Tumor Responses

Extensive studies have shown that gut microbiota-derived metabolites can enhance the antitumor efficacy of immunotherapy by modulating host immune responses. However, the more comprehensive spectrum of such metabolites and their mechanisms remain unclear. In this study, we demonstrated that L-selenomethionine (L-SeMet), a gut microbial metabolite, acts as a positive regulator of immunotherapy. Through screening of a repository of gut microbial metabolites, we identified that L-SeMet can effectively enhance the effector function of CD8+ T cells. Furthermore, intragastric administration of L-SeMet in mice significantly suppressed the growth of subcutaneous MC38 tumors. Mechanistically, L-SeMet enhances T cell receptor (TCR) signaling by promoting LCK phosphorylation. Collectively, our findings reveal that the gut microbial metabolite L-SeMet inhibits colorectal tumor growth by potentiating CD8+ T cell functions, providing a potential therapeutic strategy for colorectal cancer treatment.

Gut microbiota in colorectal cancer: a review of its influence on tumor immune surveillance and therapeutic response

Colorectal cancer (CRC) poses a significant global health burden, with gut microbiota emerging as a crucial modulator of CRC pathogenesis and therapeutic outcomes. This review synthesizes current evidence on the influence of gut microbiota on tumor immune surveillance and responses to immunotherapies and chemotherapy in CRC. We highlight the role of specific microbial taxa in promoting or inhibiting tumor growth and the potential of microbiota-based biomarkers for predicting treatment efficacy. The review also discusses the implications of microbiota modulation strategies, including diet, probiotics, and fecal microbiota transplantation, for personalized CRC management. By critically evaluating the literature, we aim to provide a comprehensive understanding of the gut microbiota's dual role in CRC and to inform future research directions in this field.

Detrimental effect of an early exposure to antibiotics on the outcomes of immunotherapy in a multi-tumor cohort of patients

BACKGROUND

Immune checkpoint inhibitors (ICI) have changed the therapeutic landscape of many solid tumors. Modulation of the intestinal microbiota by antibiotics (Abx) has been suggested to impact on ICI outcomes.

METHODS

Retrospective analysis of 475 patients with advanced solid tumors treated with ICI from 2015 to 2022. For each patient, the use of Abx was recorded from 1 month before ICI initiation until disease progression or death. The impact of Abx on objective response rates (ORR), disease control rates (DCR), progression-free survival (PFS), and overall survival (OS) was analyzed. Kaplan-Meier and log-rank tests were used to compare survival outcomes.

RESULTS

In total 475 patients with advanced solid tumors were evaluated. Median age was 67.5 years and performance status (PS) was 0-1 in 84.6%. 66.5% of patients received Abx during treatment with ICI, mainly beta-lactams (53.8%) and quinolones (35.9%). The early exposure to Abx (from 60 days before to 42 days after the first cycle of ICI) was associated with a lower ORR (27.4% vs 39.4%; P < .01), a lower DCR (37.3% vs 57.4%; P < .001), lower PFS (16.8 m vs 27.8 m; HR 0.66; P < .001]) and lower OS (2.5 m vs 6.6 m; HR 0.68; P = .001]). The negative impact of Abx on OS and PFS was confirmed by a multivariable analysis. This effect was not observed among patients receiving Abx after 6 weeks from ICI initiation.

CONCLUSIONS

Our results validate the hypothesis of a detrimental effect of an early exposure to Abxon the efficacy of ICI in a multi-tumor cohort of patients.

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).

Resistance mechanisms to immune checkpoint inhibitors: updated insights

The last decade has witnessed unprecedented succusses with the use of immune checkpoint inhibitors in treating cancer. Nevertheless, the proportion of patients who respond favorably to the treatment remained rather modest, partially due to treatment resistance. This has fueled a wave of research into potential mechanisms of resistance to immune checkpoint inhibitors which can be classified into primary resistance or acquired resistance after an initial response. In the current review, we summarize what is known so far about the mechanisms of resistance in terms of being tumor-intrinsic or tumor-extrinsic taking into account the multimodal crosstalk between the tumor, immune system compartment and other host-related factors.

Microbiome and Mucosal Immunity in the Intestinal Tract

The human bowel is exposed to numerous biotic and abiotic external noxious agents. Accordingly, the digestive tract is frequently involved in malfunctions within the organism. Together with the commensal intestinal flora, it regulates the immunological balance between inflammatory defense processes and immune tolerance. Pathological changes in this system often cause chronic inflammatory bowel diseases including Crohn's disease and ulcerative colitis. This review article highlights the complex interaction between commensal microorganisms, the intestinal microbiome, and the intestinal epithelium-localized local immune system. The main functions of the human intestinal microbiome include (i) protection against pathogenic microbial colonization, (ii) maintenance of the barrier function of the intestinal epithelium, (iii) degradation and absorption of nutrients and (iv) active regulation of the intestinal immunity. The local intestinal immune system consists primarily of macrophages, antigen-presenting cells, and natural killer cells. These cells regulate the commensal intestinal microbiome and are in turn regulated by signaling factors of the epithelial cells and the microbiome. Deregulated immune responses play an important role and can lead to both reduced activity of the commensal microbiome and pathologically increased activity of harmful microorganisms. These aspects of chronic inflammatory bowel disease have become the focus of attention in recent years. It is therefore important to consider the immunological-microbial context in both the diagnosis and treatment of inflammatory bowel diseases. A promising holistic approach would include the most comprehensive possible diagnosis of the immune and microbiome status of the patient, both at the time of diagnostics and during therapy.

Antibiotic use attenuates response to immune checkpoint blockade in urothelial carcinoma via inhibiting CD74-MIF/COPA: revealing cross-talk between anti-bacterial immunity and ant-itumor immunity

BACKGROUND

Immune checkpoint blockade (ICB) has emerged as a promising therapy for both resectable urothelial carcinoma (UC) patients preparing for radical surgery and unresectable UC patients, whereas the objective response rate of ICB remains unsatisfactory due to various factors. Antibiotic (ATB) use can influence intratumoral bacteria, which may further reduce ICB efficacy. The study aims to evaluate the effects of ATB use on prognosis and response in UC patients undergoing ICB, and explore potential molecular mechanisms of ATBs and intratumoral bacteria impacting UC immune microenvironment.

MATERIALS AND METHODS

Pooled analyses, synthesizing evidence from 3496 UC patients with ICB treatment, were conducted. In addition, single-cell RNA and single-cell microbiome data were analyzed based on eight UC samples and 63 185 single cells. Bulk RNA sequencing and clinical data from a single-arm, multicenter, atezolizumab-treated, phase 2 trial, IMvigor210, were used for validation.

RESULTS

ATB use exhibited worse overall survival (HR=1.46, 95% CI=[1.20-1.77], P <0.001 and lower objective response (OR=0.43, 95% CI=[0.27-0.68], P <0.001 in UC patients receiving ICB. Single-cell transcriptome and single-cell microbiome analyses identified the presence of intratumoral bacteria was obviously related to elevated antibacterial immune functions; and antibacterial immunity was positively correlated to antitumor immunity in UC immune microenvironment. Intratumoral bacteria could up-regulate CD74-MIF/COPA signaling of immune cells and activation of CD74-MIF/COPA mediated the promotion of T cell antitumor function induced by antibacterial immune cells. UC patients with higher CD74-MIF/COPA signaling carried better overall survival (HR=1.60, 95% CI=[1.19-2.15], P =0.002) in immunotherapy cohort.

CONCLUSION

ATB use reduces overall survival and objective response to ICB in UC patients. Antibacterial immune cell functions induced by intracellular bacteria in the UC microenvironment might up-regulate the function of antitumor T immune cells via activating CD74-MIF/COPA , whereas ATB could inhibit the above process through killing intracellular bacteria and result in poorer clinical benefit of ICB. The use of ATB should be considered carefully during the neoadjuvant immunotherapy period for resectable UC patients preparing for radical surgery and during the immunotherapy period for unresectable UC patients.

The critical role of tumor microbiome in cancer immunotherapy

In recent years, the microbiome has shown an integral role in cancer immunotherapy and has become a prominent and widely studied topic. A full understanding of the interactions between the tumor microbiome and various immunotherapies offers opportunities for immunotherapy of cancer. This review scrutinizes the composition of the tumor microbiome, the mechanism of microbial immune regulation, the influence of tumor microorganisms on tumor metastasis, and the interaction between tumor microorganisms and immunotherapy. In addition, this review also summarizes the challenges and opportunities of immunotherapy through tumor microbes, as well as the prospects and directions for future related research. In conclusion, the potential of microbial immunotherapy to enhance treatment outcomes for cancer patients should not be underestimated. Through this review, it is hoped that more research on tumor microbial immunotherapy will be done to better solve the treatment problems of cancer patients.

Delineating the nexus between gut-intratumoral microbiome and osteo-immune system in bone metastases

Emerging insights in osteoimmunology have enabled researchers to explore in depth the role of immune modulation in regulating bone health. Bone is one of the common sites of metastasis notably in case of breast cancer, prostate cancer and several other cancer types. High calcium ion concentration and presence of several factors within the mineralized bone matrix including TGF-β, BMP etc., aid in tumor growth and proliferation. Accumulating evidence has substantiated the role of the gut-microbiota (GM) in tumorigenesis, further providing a strong impetus for the growing "immune-cancer-gut microbiota" relationship. Recent advancements in research further highlight the importance of the intra-tumor microbiota in conjunction with GM in cancer metastasis. Intratumoral microbiota owing to their ability to cause genetic instability, mutations, and epigenetic modifications within the tumor microenvironment, has been recognized to affect cancer cell physiology. The host microbiota and immune system crosstalk shapes the innate and adaptive arms of the immune system, which is the key player in cancer progression. In this review, we aim to decipher the role of microorganisms mediating bone metastasis by shedding light on the immuno-onco-microbiome (IOM) axis. We discussed the feasible cancer therapeutic interventions based on the modulation of the microbiome-immune cell axis which includes prebiotics, probiotics, and postbiotics. Here, we leverage the conceptual framework based on the published articles on microbiota-based therapies to target bone metastases. Understanding this complicated nexus will provide insights into fundamental factors governing bone metastases which will subsequently help in managing this malignancy with better efficacy.

Modulation of gut microbiota by probiotics to improve the efficacy of immunotherapy in hepatocellular carcinoma

Hepatocellular carcinoma, a common malignancy of the digestive system, typically progresses through a sequence of hepatitis, liver fibrosis, cirrhosis and ultimately, tumor. The interaction between gut microbiota, the portal venous system and the biliary tract, referred to as the gut-liver axis, is crucial in understanding the mechanisms that contribute to the progression of hepatocellular carcinoma. Mechanisms implicated include gut dysbiosis, alterations in microbial metabolites and increased intestinal barrier permeability. Imbalances in gut microbiota, or dysbiosis, contributes to hepatocellular carcinoma by producing carcinogenic substances, disrupting the balance of the immune system, altering metabolic processes, and increasing intestinal barrier permeability. Concurrently, accumulating evidence suggests that gut microbiota has the ability to modulate antitumor immune responses and affect the efficacy of cancer immunotherapies. As a new and effective strategy, immunotherapy offers significant potential for managing advanced stages of hepatocellular carcinoma, with immune checkpoint inhibitors achieving significant advancements in improving patients' survival. Probiotics play a vital role in promoting health and preventing diseases by modulating metabolic processes, inflammation and immune responses. Research indicates that they are instrumental in boosting antitumor immune responses through the modulation of gut microbiota. This review is to explore the relationship between gut microbiota and the emergence of hepatocellular carcinoma, assess the contributions of probiotics to immunotherapy and outline the latest research findings, providing a safer and more cost-effective potential strategy for the prevention and management of hepatocellular carcinoma.

Longitudinal analysis of the gut microbiota during anti-PD-1 therapy reveals stable microbial features of response in melanoma patients

Immune checkpoint inhibitors (ICIs) improve outcomes in advanced melanoma, but many patients are refractory or experience relapse. The gut microbiota modulates antitumor responses. However, inconsistent baseline predictors point to heterogeneity in responses and inadequacy of cross-sectional data. We followed patients with unresectable melanoma from baseline and during anti-PD-1 therapy, collecting fecal and blood samples that were surveyed for changes in the gut microbiota and immune markers. Varying patient responses were linked to different gut microbiota dynamics during ICI treatment. We select complete responders by their stable microbiota functions and validate them using multiple external cohorts and experimentally. We identify major histocompatibility complex class I (MHC class I)-restricted peptides derived from flagellin-related genes of Lachnospiraceae (FLach) as structural homologs of tumor-associated antigens, detect FLach-reactive CD8+ T cells in complete responders before ICI therapy, and demonstrate that FLach peptides improve antitumor immunity. These findings highlight the prognostic value of microbial functions and therapeutic potential of tumor-mimicking microbial peptides.

The role of short-chain fatty acids in cancer prevention and cancer treatment

Short-chain fatty acids (SCFAs) are microbial metabolites in the gut that may play a role in cancer prevention and treatment. They affect the metabolism of both normal and cancer cells, regulating various cellular energetic processes. SCFAs also inhibit histone deacetylases, which are targets for cancer therapy. The three main SCFAs are acetate, propionate, and butyrate, which are transported into cells through specific transporters. SCFAs may enhance the efficacy of chemotherapeutic agents and modulate immune cell metabolism, potentially reprogramming the tumor microenvironment. Although SCFAs and SCFA-generating microbes enhance therapeutic efficacy of several forms of cancer therapy, published data also support the opposing viewpoint that SCFAs mitigate the efficacy of some cancer therapies. Therefore, the relationship between SCFAs and cancer is more complex, and this review discusses some of these aspects. Clearly, further research is needed to understand the role of SCFAs, their mechanisms, and applications in cancer prevention and treatment.

Host-microbe interaction-mediated resistance to DSS-induced inflammatory enteritis in sheep

BACKGROUND

The disease resistance phenotype is closely related to immunomodulatory function and immune tolerance and has far-reaching implications in animal husbandry and human health. Microbes play an important role in the initiation, prevention, and treatment of diseases, but the mechanisms of host-microbiota interactions in disease-resistant phenotypes are poorly understood. In this study, we hope to uncover and explain the role of microbes in intestinal diseases and their mechanisms of action to identify new potential treatments.

METHODS

First, we established the colitis model of DSS in two breeds of sheep and then collected the samples for multi-omics testing including metagenes, metabolome, and transcriptome. Next, we made the fecal bacteria liquid from the four groups of sheep feces collected from H-CON, H-DSS, E-CON, and E-DSS to transplant the fecal bacteria into mice. H-CON feces were transplanted into mice named HH group and H-DSS feces were transplanted into mice named HD group and Roseburia bacteria treatment named HDR groups. E-CON feces were transplanted into mice named EH group and E-DSS feces were transplanted into mice in the ED group and Roseburia bacteria treatment named EDR groups. After successful modeling, samples were taken for multi-omics testing. Finally, colitis mice in HD group and ED group were administrated with Roseburia bacteria, and the treatment effect was evaluated by H&E, PAS, immunohistochemistry, and other experimental methods.

RESULTS

The difference in disease resistance of sheep to DSS-induced colitis disease is mainly due to the increase in the abundance of Roseburia bacteria and the increase of bile acid secretion in the intestinal tract of Hu sheep in addition to the accumulation of potentially harmful bacteria in the intestine when the disease occurs, which makes the disease resistance of Hu sheep stronger under the same disease conditions. However, the enrichment of harmful microorganisms in East Friesian sheep activated the TNFα signalling pathway, which aggravated the intestinal injury, and then the treatment of FMT mice by culturing Roseburia bacteria found that Roseburia bacteria had a good curative effect on colitis.

CONCLUSION

Our study showed that in H-DSS-treated sheep, the intestinal barrier is stabilized with an increase in the abundance of beneficial microorganisms. Our data also suggest that Roseburia bacteria have a protective effect on the intestinal barrier of Hu sheep. Accumulating evidence suggests that host-microbiota interactions are associated with IBD disease progression. Video Abstract.

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.

Reassessing the role of phytochemicals in cancer chemoprevention

In this comprehensive review we tried to reassess the role of phytochemicals in cancer chemoprevention. The exploration of the "synergistic effect" concept, advocating combined chemopreventive agents, faces challenges like low bioavailability. The review incorporates personal, occasionally controversial, viewpoints on natural compounds' cancer preventive capabilities, delving into mechanisms. Prioritizing significant contributions within the vast research domain, we aim stimulating discussion to provide a comprehensive insight into the evolving role of phytochemicals in cancer prevention. While early years downplayed the role of phytochemicals, the late nineties witnessed a shift, with leaders exploring their potential alongside synthetic compounds. Challenges faced by chemoprevention, such as limited pharmaceutical interest and cost-effectiveness issues, persist despite successful drugs. Recent studies, including the EPIC study, provide nuanced insights, indicating a modest risk reduction for increased fruit and vegetable intake. Phytochemicals, once attributed to antioxidant effects, face scrutiny due to low bioavailability and conflicting evidence. The Nrf2-EpRE signaling pathway and microbiota-mediated metabolism emerge as potential mechanisms, highlighting the complexity of understanding phytochemical mechanisms in cancer chemoprevention.

Microbiota and beneficial metabolites in colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of cancer-related death worldwide. In recent years, the impact of the gut microbiota on the development of CRC has become clear. The gut microbiota is the community of microorganisms living in the gut symbiotic relationship with the host. These microorganisms contribute to the development of CRC through various mechanisms that are not yet fully understood. Increasing scientific evidence suggests that metabolites produced by the gut microbiota may influence CRC development by exerting protective and deleterious effects. This article reviews the metabolites produced by the gut microbiota, which are derived from the intake of complex carbohydrates, proteins, dairy products, and phytochemicals from plant foods and are associated with a reduced risk of CRC. These metabolites include short-chain fatty acids (SCFAs), indole and its derivatives, conjugated linoleic acid (CLA) and polyphenols. Each metabolite, its association with CRC risk, the possible mechanisms by which they exert anti-tumour functions and their relationship with the gut microbiota are described. In addition, other gut microbiota-derived metabolites that are gaining importance for their role as CRC suppressors are included.

Causal relationship between 150 skin microbiomes and prostate cancer: insights from bidirectional mendelian randomization and meta-analysis

Background

Despite relevant research, the relationship between skin microbiomes and prostate cancer remains controversial. This study utilizes bidirectional Mendelian randomization (MR) analysis combined with meta-analysis to explore the potential link between the two.

Objective

This study aims to identify the causal relationship between 150 skin microbiomes and prostate cancer (PCa) using bidirectional Mendelian randomization (MR) and meta-analysis.

Methods

This study employed a comprehensive Bidirectional Two-sample MR analysis using publicly available genetic data to ascertain the relationship between 150 skin microbiomes and PCa. We conducted extensive sensitivity analyses, tests for heterogeneity, and assessments of horizontal pleiotropy to ensure the accuracy of our results. Subsequently, we conducted a meta-analysis to strengthen our conclusions' robustness further. Finally, we performed reverse causal verification on the positive skin microbiomes and PCa.

Results

After conducting a meta-analysis and multiple corrections of the MR analysis results, our findings reveal a correlation between Neisseria in dry skin and PCa risk, identifying it as a risk factor. The IVW result shows an Odds Ratio (OR) of 1.009 (95% Confidence Interval [CI]: 1.004-1.014, P = 0.027). Furthermore, the reverse MR analysis indicates the absence of an inverse causal relationship between the two. Apart from the identified skin microbiome, no significant associations were found between the other microbiomes and PCa.

Conclusions

The study identified a correlation between Neisseria in dry skin, one of the 150 skin microbiomes, and the risk of developing PCa, establishing it as a risk factor for increased susceptibility to PCa.

Metabolic mediators: microbial-derived metabolites as key regulators of anti-tumor immunity, immunotherapy, and chemotherapy

The human microbiome has recently emerged as a focal point in cancer research, specifically in anti-tumor immunity, immunotherapy, and chemotherapy. This review explores microbial-derived metabolites, emphasizing their crucial roles in shaping fundamental aspects of cancer treatment. Metabolites such as short-chain fatty acids (SCFAs), Trimethylamine N-Oxide (TMAO), and Tryptophan Metabolites take the spotlight, underscoring their diverse origins and functions and their profound impact on the host immune system. The focus is on SCFAs' remarkable ability to modulate immune responses, reduce inflammation, and enhance anti-tumor immunity within the intricate tumor microenvironment (TME). The review critically evaluates TMAO, intricately tied to dietary choices and gut microbiota composition, assessing its implications for cancer susceptibility, progression, and immunosuppression. Additionally, the involvement of tryptophan and other amino acid metabolites in shaping immune responses is discussed, highlighting their influence on immune checkpoints, immunosuppression, and immunotherapy effectiveness. The examination extends to their dynamic interaction with chemotherapy, emphasizing the potential of microbial-derived metabolites to alter treatment protocols and optimize outcomes for cancer patients. A comprehensive understanding of their role in cancer therapy is attained by exploring their impacts on drug metabolism, therapeutic responses, and resistance development. In conclusion, this review underscores the pivotal contributions of microbial-derived metabolites in regulating anti-tumor immunity, immunotherapy responses, and chemotherapy outcomes. By illuminating the intricate interactions between these metabolites and cancer therapy, the article enhances our understanding of cancer biology, paving the way for the development of more effective treatment options in the ongoing battle against cancer.

What prognostic factors have impacted the efficacy of immune checkpoint inhibitors in patients with recurrent or metastatic oral cancer?

BACKGROUND

Immune checkpoint inhibitors (ICIs) are widely adapted for recurrent or metastatic head and neck cancer (RM-HNC), and various studies on its prognostic factors have been reported. We aimed to elucidate the prognostic factors of ICI treatment for RM oral cancer (RM-OC) in a retrospective study.

METHODS

We retrospectively reviewed patients with RM-OC treated with ICIs (nivolumab and pembrolizumab) at our department from May 2017 to February 2023. The objective response rate (ORR) for ICI treatment and the relationship between several potential prognostic factors, progression-free survival (PFS), and overall survival (OS) were analyzed statistically.

RESULTS

The investigation enrolled 31 patients, 16 with nivolumab and 15 with pembrolizumab. There were no significant differences in the ORR or disease control rate between the nivolumab and pembrolizumab groups (p = 0.4578 and 0.2524). In multivariate analysis, the prognostic nutritional index (PNI) and C-reactive protein to albumin ratio (CAR) exhibited statistical correlations with PFS, whereas the use of antibiotics and proton pump inhibitors (PPIs), neutrophil to lymphocyte ratio (NLR), and PNI demonstrated statistical associations with OS.

CONCLUSION

Our findings imply that the use of antibiotics and PPIs, which can modify the gut microbiota, may also serve as a prognostic determinant for ICI treatment in RM-OC, consistent with previous studies. Additionally, PNI may be essential in affecting the survival rates of both PFS and OS and could be an exceedingly valuable inflammatory biomarker for RM-OC.

Targeting the gut microbiota to alleviate chemotherapy-induced toxicity in cancer

Despite ongoing breakthroughs in novel anticancer therapies, chemotherapy remains a mainstream therapeutic modality in different types of cancer. Unfortunately, chemotherapy-related toxicity (CRT) often leads to dose limitation, and even results in treatment termination. Over the past few years, accumulating evidence has indicated that the gut microbiota is extensively engaged in various toxicities initiated by chemotherapeutic drugs, either directly or indirectly. The gut microbiota can now be targeted to reduce the toxicity of chemotherapy. In the current review, we summarized the clinical relationship between the gut microbiota and CRT, as well as the critical role of the gut microbiota in the occurrence and development of CRT. We then summarized the key mechanisms by which the gut microbiota modulates CRT. Furthermore, currently available strategies to mitigate CRT by targeting the gut microbiota were summarized and discussed. This review offers a novel perspective for the mitigation of diverse chemotherapy-associated toxic reactions in cancer patients and the future development of innovative drugs or functional supplements to alleviate CRT via targeting the gut microbiota.

Global research trends on the associations between the microbiota and lung cancer: a visualization bibliometric analysis (2008-2023)

Numerous papers have been published on the microbiota in lung cancer in recent years. However, there is still a lack of bibliometric analysis of the microbiota in lung cancer in this field. Our paper did bibliometric analyses and elucidated the knowledge structure and study hotspots related to the microbiota in lung cancer patients. We screened publications reporting on the microbiota in lung cancer from 2008 to 2023 from the Web of Science Core Collection (WoSCC) database, and carried out bibliometric analyses by the application of the VOSviewers, CiteSpace and R package "bibliometrix." The 684 documents enrolled in the analysis were obtained from 331 institutions in 67 regions by 4,661 authors and were recorded in 340 journals. Annual papers are growing rapidly, and the countries of China, the United States and Italy are contributing the most to this area of research. Zhejiang University is the main research organization. Science and Cancer had significant impacts on this area. Zhang Yan had the most articles, and the Bertrand Routy had the most co-cited times. Exploring the mechanism of action of the lung and/or gut microbiota in lung cancer and therapeutic strategies involving immune checkpoint inhibitors in lung cancer are the main topics. Moreover, "gut microbiota," "immunotherapy," and "short-chain fatty acids" are important keywords for upcoming study hotspots. In conclusion, microbiota research offers promising opportunities in lung cancer, with pivotal studies exploring the mechanisms that link lung and gut microbiota to therapeutic strategies, particularly through immune checkpoint inhibitors. Moreover, the gut-lung axis emerges as a novel target for innovative treatments. Further research is essential to unravel the detailed mechanisms of this connection.

Flavonoids in mitigating the adverse effects of canine endotoxemia

In dogs, chronic enteropathies, and impaired gut integrity, as well as microbiome imbalances, are a major problem. These conditions may represent a continuous low endotoxin load, which may result in the development of diseases that are attributable to chronic inflammation. Flavonoids are polyphenolic plant compounds with numerous beneficial properties such as antioxidant, anti-inflammatory and antimicrobial effects. For our experiments, we isolated primary white blood cells (peripheral blood mononuclear cells and polymorphonuclear leukocytes) from healthy dogs and induced inflammation and oxidative stress with Escherichia coli and Salmonella enterica serovar Enteritidis lipopolysaccharide (LPS). In parallel, we treated the cell cultures with various flavonoids luteolin, quercetin and grape seed extract oligomeric proanthocyanidins (GSOP) alone and also in combination with LPS treatments. Then, changes in viability, reactive oxygen species (ROS) and tumor necrosis factor alpha (TNF-α) levels were measured in response to treatment with quercetin, luteolin and GSOP at 25 and 50 μg/mL concentrations. We found that ROS levels were significantly lower in groups which were treated by flavonoid and LPS at the same time compared to LPS-treated groups, whereas TNF-α levels were significantly reduced only by luteolin and quercetin treatment. In contrast, treatment with lower concentrations of GSOP caused an increase in TNF-α levels, while higher concentrations caused a significant decrease. These results suggest that the use of quercetin, luteolin and GSOP may be helpful in the management of chronic intestinal diseases in dogs with reduced intestinal barrier integrity or altered microbiome composition, or in the mitigation of chronic inflammatory processes maintained by endotoxemia. Further in vitro and in vivo studies are needed before clinical use.

Lower respiratory tract microbiome and lung cancer risk prediction in patients with diffuse lung parenchymal lesions

Objective

In clinical practice, imaging manifestations of diffuse lung parenchymal lesions are common and indicative of various diseases, making differential diagnosis difficult. Some of these lesions are eventually diagnosed as lung cancer.

Methods

Because respiratory microorganisms play an important role in lung cancer development, we searched for microbial markers that could predict the risk of lung cancer by retrospectively analyzing the lower respiratory tract (LRT) microbiome of 158 patients who were hospitalized in the First Affiliated Hospital of Guangzhou Medical University (March 2021-March 2023) with diffuse lung parenchymal lesions. The final diagnosis was lung cancer in 21 cases, lung infection in 93 cases, and other conditions (other than malignancy and infections) in 44 cases. The patient's clinical characteristics and the results of metagenomic next-generation sequencing of bronchoalveolar lavage fluid (BALF) were analyzed.

Results

Body mass index (BMI) and LRT microbial diversity (Shannon, Simpson, species richness, and Choa1 index) were significantly lower (P< 0.001, respectively) and Lactobacillus acidophilus relative abundance in the LRT was significantly higher (P< 0.001) in patients with lung cancer. The relative abundance of L. acidophilus in BALF combined with BMI was a good predictor of lung cancer risk (area under the curve = 0.985, accuracy = 98.46%, sensitivity = 95.24%, and specificity = 100.00%; P< 0.001).

Conclusion

Our study showed that an imbalance in the component ratio of the microbial community, diminished microbial diversity, and the presence of specific microbial markers in the LRT predicted lung cancer risk in patients with imaging manifestations of diffuse lung parenchymal lesions.

Systematic review on the role of the gut microbiota in tumors and their treatment

Tumors present a formidable health risk with limited curability and high mortality; existing treatments face challenges in addressing the unique tumor microenvironment (hypoxia, low pH, and high permeability), necessitating the development of new therapeutic approaches. Under certain circumstances, certain bacteria, especially anaerobes or parthenogenetic anaerobes, accumulate and proliferate in the tumor environment. This phenomenon activates a series of responses in the body that ultimately produce anti-tumor effects. These bacteria can target and colonize the tumor microenvironment, promoting responses aimed at targeting and fighting tumor cells. Understanding and exploiting such interactions holds promise for innovative therapeutic strategies, potentially augmenting existing treatments and contributing to the development of more effective and targeted approaches to fighting tumors. This paper reviews the tumor-promoting mechanisms and anti-tumor effects of the digestive tract microbiome and describes bacterial therapeutic strategies for tumors, including natural and engineered anti-tumor strategies.

Targeting bacterial metabolites in tumor for cancer therapy: An alternative approach for targeting tumor-associated bacteria

Emerging evidence reveal that tumor-associated bacteria (TAB) can facilitate the initiation and progression of multiple types of cancer. Recent work has emphasized the significant role of intestinal microbiota, particularly bacteria, plays in affecting responses to chemo- and immuno-therapies. Hence, it seems feasible to improve cancer treatment outcomes by targeting intestinal bacteria. While considering variable richness of the intestinal microbiota and diverse components among individuals, direct manipulating the gut microbiota is complicated in clinic. Tumor initiation and progression requires the gut microbiota-derived metabolites to contact and reprogram neoplastic cells. Hence, directly targeting tumor-associated bacteria metabolites may have the potential to provide alternative and innovative strategies to bypass the gut microbiota for cancer therapy. As such, there are great opportunities to explore holistic approaches that incorporates TAB-derived metabolites and related metabolic signals modulation for cancer therapy. In this review, we will focus on key opportunistic areas by targeting TAB-derived metabolites and related metabolic signals, but not bacteria itself, for cancer treatment, and elucidate future challenges that need to be addressed in this emerging field.

The engineered agonistic anti-CD40 antibody potentiates the antitumor effects of β-glucan by resetting TAMs

Anti-CD40 antibodies (Abs) have been shown to induce antitumor T-cell responses. We reported that the engineered agonistic anti-CD40 Ab (5C11, IgG4 isotype) recognized human CD40 antigen expressed on a human B lymphoblastoid cell line as well as on splenic cells isolated from humanized CD40 mice. Of note, a single high dosage of 5C11 was able to prohibit tumor growth in parallel with an increase in the population of infiltrated CD8+ T cells. Furthermore, the antitumor effects of 5C11 were enhanced in the presence of β-glucan along with an increase in the population of infiltrated CD8+ T cells. In addition, the numbers of CD86+ TAMs and neutrophils were elevated in the combination of 5C11 and β-glucan compared with either 5C11 or β-glucan alone. Furthermore, the abundance of Faecalibaculum, one of the probiotics critical for tumor suppression, was obviously increased in the combination of 5C11 and β-glucan-treated mice. These data reveal a novel mechanism of tumor suppression upon the combination treatment of 5C11 and β-glucan and propose that the combination treatment of agonistic anti-human CD40 antibody 5C11 and β-glucan could be a promising therapeutic strategy for cancer patients.

Harnessing microbial antigens as cancer antigens: a promising avenue for cancer immunotherapy

Immunotherapy has revolutionized cancer treatment by leveraging the immune system's innate capabilities to combat malignancies. Despite the promise of tumor antigens in stimulating anti-tumor immune responses, their clinical utility is hampered by limitations in eliciting robust and durable immune reactions, exacerbated by tumor heterogeneity and immune evasion mechanisms. Recent insights into the immunogenic properties of host homologous microbial antigens have sparked interest in their potential for augmenting anti-tumor immunity while minimizing off-target effects. This review explores the therapeutic potential of microbial antigen peptides in tumor immunotherapy, beginning with an overview of tumor antigens and their challenges in clinical translation. We further explore the intricate relationship between microorganisms and tumor development, elucidating the concept of molecular mimicry and its implications for immune recognition of tumor-associated antigens. Finally, we discuss methodologies for identifying and characterizing microbial antigen peptides, highlighting their immunogenicity and prospects for therapeutic application.

Microbiota-associated mechanisms in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide, ranking third in terms of incidence and second as a cause of cancer-related death. There is growing scientific evidence that the gut microbiota plays a key role in the initiation and development of CRC. Specific bacterial species and complex microbial communities contribute directly to CRC pathogenesis by promoting the neoplastic transformation of intestinal epithelial cells or indirectly through their interaction with the host immune system. As a result, a protumoural and immunosuppressive environment is created conducive to CRC development. On the other hand, certain bacteria in the gut microbiota contribute to protection against CRC. In this chapter, we analysed the relationship of the gut microbiota to CRC and the associations identified with specific bacteria. Microbiota plays a key role in CRC through various mechanisms, such as increased intestinal permeability, inflammation and immune system dysregulation, biofilm formation, genotoxin production, virulence factors and oxidative stress. Exploring the interaction between gut microbiota and tumourigenesis is essential for developing innovative therapeutic approaches in the fight against CRC.

Engineered Microorganisms for Advancing Tumor Therapy

Engineered microorganisms have attracted significant interest as a unique therapeutic platform in tumor treatment. Compared with conventional cancer treatment strategies, engineering microorganism-based systems provide various distinct advantages, such as the intrinsic capability in targeting tumors, their inherent immunogenicity, in situ production of antitumor agents, and multiple synergistic functions to fight against tumors. Herein, the design, preparation, and application of the engineered microorganisms for advanced tumor therapy are thoroughly reviewed. This review presents a comprehensive survey of innovative tumor therapeutic strategies based on a series of representative engineered microorganisms, including bacteria, viruses, microalgae, and fungi. Specifically, it offers extensive analyses of the design principles, engineering strategies, and tumor therapeutic mechanisms, as well as the advantages and limitations of different engineered microorganism-based systems. Finally, the current challenges and future research prospects in this field, which can inspire new ideas for the design of creative tumor therapy paradigms utilizing engineered microorganisms and facilitate their clinical applications, are discussed.

It Is All about Probiotics to Control Cervical Cancer

Cervical cancer (CC) is the fourth most common malignancy in female patients. "Human papillomavirus" (HPV) contamination is a leading cause of all forms of cervical cancer, accounting for an expected 570,000 reported incidents in 2018. Two HPV strains (16 and 18) are responsible for 70% of CC and pre-cancerous cervical abnormalities. CC is one of the foremost reasons for the malignancy death rate in India among women ranging from 30 to 69 years of age in India, responsible for 17% of all cancer deaths. Currently approved cervical cancer treatments are associated with adverse reactions that might harm the lives of women affected by this disease. Consequently, probiotics can play a vital role in the treatment of CC. It is reflected from various studies regarding the role of probiotics in the diagnosis, prevention or treatment of cancer. In this review article, we have discussed the rationale of probiotics for treatment of CC, the role of probiotics as effective adjuvants in anti-cancer therapy and the combined effect of the anti-cancer drug along with probiotics to minimize the side effects due to chemotherapy.

The bacterial metabolite, lithocholic acid, has antineoplastic effects in pancreatic adenocarcinoma

Lithocholic acid (LCA) is a secondary bile acid. LCA enters the circulation after bacterial synthesis in the gastrointestinal tract, reaches distantly located cancer cells, and influences their behavior. LCA was considered carcinogenic, but recent studies demonstrated that LCA has antitumor effects. We assessed the possible role of LCA in pancreatic adenocarcinoma. At the serum reference concentration, LCA induced a multi-pronged antineoplastic program in pancreatic adenocarcinoma cells. LCA inhibited cancer cell proliferation and induced mesenchymal-to-epithelial (MET) transition that reduced cell invasion capacity. LCA induced oxidative/nitrosative stress by decreasing the expression of nuclear factor, erythroid 2-like 2 (NRF2) and inducing inducible nitric oxide synthase (iNOS). The oxidative/nitrosative stress increased protein nitration and lipid peroxidation. Suppression of oxidative stress by glutathione (GSH) or pegylated catalase (pegCAT) blunted LCA-induced MET. Antioxidant genes were overexpressed in pancreatic adenocarcinoma and decreased antioxidant levels correlated with better survival of pancreatic adenocarcinoma patients. Furthermore, LCA treatment decreased the proportions of cancer stem cells. Finally, LCA induced total and ATP-linked mitochondrial oxidation and fatty acid oxidation. LCA exerted effects through the farnesoid X receptor (FXR), vitamin D receptor (VDR), and constitutive androstane receptor (CAR). LCA did not interfere with cytostatic agents used in the chemotherapy of pancreatic adenocarcinoma. Taken together, LCA is a non-toxic compound and has antineoplastic effects in pancreatic adenocarcinoma.

Interplay Between Drug-Induced Liver Injury and Gut Microbiota: A Comprehensive Overview

Drug-induced liver injury is a prevalent severe adverse event in clinical settings, leading to increased medical burdens for patients and presenting challenges for the development and commercialization of novel pharmaceuticals. Research has revealed a close association between gut microbiota and drug-induced liver injury in recent years. However, there has yet to be a consensus on the specific mechanism by which gut microbiota is involved in drug-induced liver injury. Gut microbiota may contribute to drug-induced liver injury by increasing intestinal permeability, disrupting intestinal metabolite homeostasis, and promoting inflammation and oxidative stress. Alterations in gut microbiota were found in drug-induced liver injury caused by antibiotics, psychotropic drugs, acetaminophen, antituberculosis drugs, and antithyroid drugs. Specific gut microbiota and their abundance are associated closely with the severity of drug-induced liver injury. Therefore, gut microbiota is expected to be a new target for the treatment of drug-induced liver injury. This review focuses on the association of gut microbiota with common hepatotoxic drugs and the potential mechanisms by which gut microbiota may contribute to the pathogenesis of drug-induced liver injury, providing a more comprehensive reference for the interaction between drug-induced liver injury and gut microbiota.

Dissecting Gut-Microbial Community Interactions using a Gut Microbiome-on-a-Chip

While the human gut microbiota has a significant impact on gut health and disease, understanding of the roles of gut microbes, interactions, and collective impact of gut microbes on various aspects of human gut health is limited by the lack of suitable in vitro model system that can accurately replicate gut-like environment and enable the close visualization on causal and mechanistic relationships between microbial constitutents and the gut. , In this study, we present a scalable Gut Microbiome-on-a-Chip (GMoC) with great imaging capability and scalability, providing a physiologically relevant dynamic gut-microbes interfaces. This chip features a reproducible 3D stratified gut epithelium derived from Caco-2 cells (µGut), mimicking key intestinal architecture, functions, and cellular complexity, providing a physiolocially relevant gut environment for microbes residing in the gut. Incorporating tumorigenic bacteria, enterotoxigenic Bacteroides fragilis (ETBF), into the GMoC enable the observation of pathogenic behaviors of ETBF, leading to µGut disruption and pro-tumorigenic signaling activations. Pre-treating the µGut with a beneficial gut microbe Lactobacillus spp., effectively prevent ETBF-mediated gut pathogenesis, preserving the healthy state of the µGut through competition-mediated colonization resistance. The GMoC holds potential as a valuable tool for exploring unknown roles of gut microbes in microbe-induced pathogenesis and microbe-based therapeutic development.

Targeted modulation of gut and intra-tumor microbiota to improve the quality of immune checkpoint inhibitor responses

Immune checkpoint inhibitor (ICI) therapies, such as those blocking the interaction of PD-1 with its ligands, can restore the immune-killing function of T cells. However, ICI therapy is clinically beneficial in only a small number of patients, and it is difficult to predict post-treatment outcomes, thereby limiting its widespread clinical use. Research suggests that gut microbiota can regulate the host immune system and affect cancer progression and treatment. Moreover, the effectiveness of immunotherapy is related to the composition of the patient's gut microbiota; different gut microbial strains can either activate or inhibit the immune response. However, the importance of the microbial composition within the tumor has not been explored until recently. This study describes recent advances in the crosstalk between microbes in tumors and gut microbiota, which can modulate the tumor microbiome by directly translocating into the tumor and altering the tumor microenvironment. This study focused on the potential manipulation of the tumor and gut microbiota using fecal microbiota transplantation (FMT), probiotics, antimicrobials, prebiotics, and postbiotics to enrich immune-boosting bacteria while decreasing unfavorable bacteria to proactively improve the efficacy of ICI treatments. In addition, the use of genetic technologies and nanomaterials to modify microorganisms can largely optimize tumor immunotherapy and advance personalized and precise cancer treatment.

Porphyromonas gingivalis suppresses oral squamous cell carcinoma progression by inhibiting MUC1 expression and remodeling the tumor microenvironment

Bacteria are the causative agents of various infectious diseases; however, the anti-tumor effect of some bacterial species has attracted the attention of many scientists. The human oral cavity is inhabited by abundant and diverse bacterial communities and some of these bacterial communities could play a role in tumor suppression. Therefore, it is crucial to find oral bacterial species that show anti-tumor activity on oral cancers. In the present study, we found that a high abundance of Porphyromonas gingivalis, an anaerobic periodontal pathogen, in the tumor microenvironment (TME) was positively associated with the longer survival of patients with oral squamous cell carcinoma (OSCC). An in vitro assay confirmed that P. gingivalis accelerated the death of OSCC cells by inducing cell cycle arrest at the G2/M phase, thus exerting its anti-tumor effect. We also found that P. gingivalis significantly decreased tumor growth in a 4-nitroquinoline-1-oxide-induced in situ OSCC mouse model. The transcriptomics data demonstrated that P. gingivalis suppressed the biosynthesis of mucin O-glycan and other O-glycans, as well as the expression of chemokines. Validation experiments further confirmed the downregulation of mucin-1 (MUC1) and C-X-C motif chemokine 17 (CXCL17) expression by P. gingivalis treatment. Flow cytometry analysis showed that P. gingivalis successfully reversed the immunosuppressive TME, thereby suppressing OSCC growth. In summary, the findings of the present study indicated that the rational use of P. gingivalis could serve as a promising therapeutic strategy for OSCC.

Microbiome and cancer: from mechanistic implications in disease progression and treatment to development of novel antitumoral strategies

Cancer is a very aggressive disease and one of mankind's most important health problems, causing numerous deaths each year. Its etiology is complex, including genetic, gender-related, infectious diseases, dysbiosis, immunological imbalances, lifestyle, including dietary factors, pollution etc. Cancer patients also become immunosuppressed, frequently as side effects of chemotherapy and radiotherapy, and prone to infections, which further promote the proliferation of tumor cells. In recent decades, the role and importance of the microbiota in cancer has become a hot spot in human biology research, bringing together oncology and human microbiology. In addition to their roles in the etiology of different cancers, microorganisms interact with tumor cells and may be involved in modulating their response to treatment and in the toxicity of anti-tumor therapies. In this review, we present an update on the roles of microbiota in cancer with a focus on interference with anticancer treatments and anticancer potential.

Microbiome bacterial influencers of host immunity and response to immunotherapy

The gut microbiota influences anti-tumor immunity and can induce or inhibit response to immune checkpoint inhibitors (ICIs). Therefore, microbiome features are being studied as predictive/prognostic biomarkers of patient response to ICIs, and microbiome-based interventions are attractive adjuvant treatments in combination with ICIs. Specific gut-resident bacteria can influence the effectiveness of immunotherapy; however, the mechanism of action on how these bacteria affect anti-tumor immunity and response to ICIs is not fully understood. Nevertheless, early bacterial-based therapeutic strategies have demonstrated that targeting the gut microbiome through various methods can enhance the effectiveness of ICIs, resulting in improved clinical responses in patients with a diverse range of cancers. Therefore, understanding the microbiota-driven mechanisms of response to immunotherapy can augment the success of these interventions, particularly in patients with treatment-refractory cancers.

Bile acids modified by the intestinal microbiota promote colorectal cancer growth by suppressing CD8+ T cell effector functions

Concentrations of the secondary bile acid, deoxycholic acid (DCA), are aberrantly elevated in colorectal cancer (CRC) patients, but the consequences remain poorly understood. Here, we screened a library of gut microbiota-derived metabolites and identified DCA as a negative regulator for CD8+ T cell effector function. Mechanistically, DCA suppressed CD8+ T cell responses by targeting plasma membrane Ca2+ ATPase (PMCA) to inhibit Ca2+-nuclear factor of activated T cells (NFAT)2 signaling. In CRC patients, CD8+ T cell effector function negatively correlated with both DCA concentration and expression of a bacterial DCA biosynthetic gene. Bacteria harboring DCA biosynthetic genes suppressed CD8+ T cells effector function and promoted tumor growth in mice. This effect was abolished by disrupting bile acid metabolism via bile acid chelation, genetic ablation of bacterial DCA biosynthetic pathway, or specific bacteriophage. Our study demonstrated causation between microbial DCA metabolism and anti-tumor CD8+ T cell response in CRC, suggesting potential directions for anti-tumor therapy.

Causal associations between gut microbiota and cutaneous melanoma: a Mendelian randomization study

Background

Cutaneous melanoma (CM) of the skin stands as the leading cause of mortality among skin cancer-related deaths. Despite the successes achieved with novel therapies such as immunotherapy and targeted therapy, their efficacy remains limited, necessitating further exploration of new treatment modalities. The gut microbiota and CM may be linked, as indicated by a growing body of preclinical and observational research. Nevertheless, the exact correlation between the intestinal microbiota and CM remains to be determined. Therefore, this study aims to assess the potential causal relationship between the gut microbiota and CM.

Methods

The study utilized exposure data obtained from the MiBioGen consortium's microbiome GWAS, which included a total of 18,340 samples gathered from 24 population-based cohorts. Data at the summary level for CM were acquired from the UK Biobank investigation. The main analytical strategy utilized in this research was the inverse variance weighted (IVW) technique, supported by quality assurance measures like the weighted median model, MR-Egger, simple model, and weighted model approaches. The Cochran's Q test was used to evaluate heterogeneity. To ascertain potential pleiotropy, we employed both the MR-Egger regression and the MR-PRESSO test. Sensitivity analysis was conducted using the leave-one-out method.

Results

The study found that the class Bacteroidia (OR = 0.997, 95% CI: 0.995-0.999, p = 0.027), genus Parabacteroides (OR = 0.997, 95% CI: 0.994-0.999, p = 0.037), order Bacteroidales (OR = 0.997, 95% CI: 0.995-0.999, p = 0.027), and genus Veillonella (OR = 0.998, 95% CI: 0.996-0.999, p = 0.046) have protective effects on CM. On the order hand, the genus Blautia (OR = 1.003, 95% CI: 1-1.006, p = 0.001) and phylum Cyanobacteria (OR = 1.002, 95% CI: 1-1.004, p = 0.04) are identified as risk factors for CM.

Conclusion

We comprehensively assessed the potential causal relationship between the gut microbiota and CM and identified associations between six gut microbiota and CM. Among these, four gut microbiota were identified as protective factors for CM, while two gut microbiota were identified as risk factors for CM. This study effectively established a causal relationship between the gut microbiota and CM, thereby providing valuable insights into the mechanistic pathways through which the microbiota impacts the progression of CM.

Intra-bone marrow injection with engineered Lactococcus lactis for the treatment of metastatic tumors: Primary report

Bone marrow has the capacity to produce different types of immune cells, such as natural killer cells, macrophages, dendritic cells (DCs) and T cells. Improving the activation of immune cells in the bone marrow can enhance the therapy of bone metastases. Previously, we designed an engineered probiotic Lactococcus lactis, capable of expressing a fusion protein of Fms-like tyrosine kinase 3 ligand and co-stimulator OX40 ligand (FOLactis), and proved that it can induce the activation and differentiation of several immune cells. In this research, we successfully establish mouse models of bone metastasis, lung metastasis and intraperitoneal dissemination, and we are the first to directly inject the probiotics into the bone marrow to inhibit tumor growth. We observe that injecting FOLactis into the bone marrow of mice can better regulate the immune microenvironment of tumor-bearing mice, resulting in a tumor-suppressive effect. Compared to subcutaneous (s.c.) injection, intra-bone marrow (IBM) injection is more effective in increasing mature DCs and CD8+ T cells and prolonging the survival of tumor-bearing mice. Our results confirm that IBM injection of FOLactis reprograms the immune microenvironment of bone marrow and has remarkable effectiveness in various metastatic tumor models.

Targeting the gut microbiota to enhance the antitumor efficacy and attenuate the toxicity of CAR-T cell therapy: a new hope?

Chimeric antigen receptor (CAR) -T cell therapy has achieved tremendous efficacy in the treatment of hematologic malignancies and represents a promising treatment regimen for cancer. Despite the striking response in patients with hematologic malignancies, most patients with solid tumors treated with CAR-T cells have a low response rate and experience major adverse effects, which indicates the need for biomarkers that can predict and improve clinical outcomes with future CAR-T cell treatments. Recently, the role of the gut microbiota in cancer therapy has been established, and growing evidence has suggested that gut microbiota signatures may be harnessed to personally predict therapeutic response or adverse effects in optimizing CAR-T cell therapy. In this review, we discuss current understanding of CAR-T cell therapy and the gut microbiota, and the interplay between the gut microbiota and CAR-T cell therapy. Above all, we highlight potential strategies and challenges in harnessing the gut microbiota as a predictor and modifier of CAR-T cell therapy efficacy while attenuating toxicity.

Unlocking the secrets: exploring the influence of the aryl hydrocarbon receptor and microbiome on cancer development

Gut microbiota regulates various aspects of human physiology by producing metabolites, metabolizing enzymes, and toxins. Many studies have linked microbiota with human health and altered microbiome configurations with the occurrence of several diseases, including cancer. Accumulating evidence suggests that the microbiome can influence the initiation and progression of several cancers. Moreover, some microbiotas of the gut and oral cavity have been reported to infect tumors, initiate metastasis, and promote the spread of cancer to distant organs, thereby influencing the clinical outcome of cancer patients. The gut microbiome has recently been reported to interact with environmental factors such as diet and exposure to environmental toxicants. Exposure to environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) induces a shift in the gut microbiome metabolic pathways, favoring a proinflammatory microenvironment. In addition, other studies have also correlated cancer incidence with exposure to PAHs. PAHs are known to induce organ carcinogenesis through activating a ligand-activated transcriptional factor termed the aryl hydrocarbon receptor (AhR), which metabolizes PAHs to highly reactive carcinogenic intermediates. However, the crosstalk between AhR and the microbiome in mediating carcinogenesis is poorly reviewed. This review aims to discuss the role of exposure to environmental pollutants and activation of AhR on microbiome-associated cancer progression and explore the underlying molecular mechanisms involved in cancer development.

Neutrophil hitchhiking nanoparticles enhance bacteria-mediated cancer therapy via NETosis reprogramming

Bacteria have shown great potential in anti-tumor treatment, and an attenuated strain of Salmonella named VNP20009 has been shown to be safe in clinical trials. However, colonized bacteria recruit neutrophils into the tumor, which release NETs to capture and eliminate bacteria, compromising bacterial-based tumor treatment. In this study, we report a neutrophil hitchhiking nanoparticles (SPPS) that block the formation of NET to enhance bacteria-mediated tumor therapy. In the 4 T1 tumor-bearing mouse model, following 24 h of bacterial therapy, there was an approximately 3.0-fold increase in the number of neutrophils in the bloodstream, while the amount of SPPS homing to tumor tissue through neutrophil hitchhiking increased approximately 2.0-fold. It is worth noting that the NETs in tumors significantly decreased by approximately 2.0-fold through an intracellular ROS scavenging-mediated NETosis reprogramming, thereby increasing bacterial vitality by 1.9-fold in tumors. More importantly, the gene drug (siBcl-2) loaded in SPPS can be re-encapsulated in apoptotic bodies by reprogramming neutrophils from NETosis to apoptosis, and enable the redelivery of drugs to tumor cells, further boosting the antitumor efficacy with a synergistic effect, resulting in about 98% tumor inhibition rate and 90% survival rate.