Dietary fiber and probiotics influence the gut microbiome and melanoma immunotherapy response

Effects of gut microbiota on immune checkpoint inhibitors in multi-cancer and as microbial biomarkers for predicting therapeutic response

BACKGROUND

Gut bacteria are related to immune checkpoint inhibitors (ICIs). However, there is inconsistency in ICI-associated species, while the role of non-bacterial microbes in immunotherapy remains elusive. Here, we evaluated the association of trans-kingdom microbes with ICIs by multi-cohort multi-cancer analyses.

METHODS

We retrieved fecal metagenomes from 1,359 ICI recipients with four different cancers (metastatic melanoma [MM], non-small cell lung carcinoma [NSCLC], renal cell cancer [RCC], and hepatocellular carcinoma) from 12 published datasets. Microbiota composition was analyzed using the Wilcoxon rank test. The performance of microbial biomarkers in predicting ICI response was assessed by random forest. Key responder-associated microbes were functionally examined in vitro and in mice.

FINDINGS

Trans-kingdom gut microbiota (bacteria, eukaryotes, viruses, and archaea) was significantly different between ICI responders and non-responders in multi-cancer. Bacteria (Faecalibacterium prausnitzii, Coprococcus comes) and eukaryotes (Nemania serpens, Hyphopichia pseudoburtonii) were consistently enriched in responders of ≥2 cancer types or from ≥3 cohorts, contrasting with the depleted bacterium Hungatella hathewayi. Responder-associated species in each cancer were revealed, such as F. prausnitzii in MM and 6 species in NSCLC. These signature species influenced ICI efficacy by modulating CD8+ T cell activity in vitro and in mice. Moreover, bacterial and eukaryotic biomarkers showed great performance in predicting ICI response in patients from discovery and two validation cohorts (MM: area under the receiver operating characteristic curve [AUROC] = 72.27%-80.19%; NSCLC: AUROC = 72.70%-87.98%; RCC: AUROC = 83.33%-89.58%).

CONCLUSIONS

This study identified trans-kingdom microbial signatures associated with ICI in multi-cancer and specific cancer types. Trans-kingdom microbial biomarkers are potential predictors of ICI response in patients with cancer.

FUNDING

Funding information is shown in the acknowledgments.

Gut microbiota as a new target for anticancer therapy: from mechanism to means of regulation

In order to decipher the relationship between gut microbiota imbalance and cancer, this paper reviewed the role of intestinal microbiota in anticancer therapy and related mechanisms, discussed the current research status of gut microbiota as a biomarker of cancer, and finally summarized the reasonable means of regulating gut microbiota to assist cancer therapy. Overall, our study reveals that the gut microbiota can serve as a potential target for improving cancer management.

Oronasal mucosal melanoma is defined by two transcriptional subtypes in humans and dogs with implications for diagnosis and therapy

Mucosal melanoma is a rare melanoma subtype associated with a poor prognosis and limited existing therapeutic interventions, in part due to a lack of actionable targets and translational animal models for preclinical trials. Comprehensive data on this tumour type are scarce, and existing data often overlooks the importance of the anatomical site of origin. We evaluated human and canine oronasal mucosal melanoma (OMM) to determine whether the common canine disease could inform the rare human equivalent. Using a human and canine primary OMM cohort of treatment-naive archival tissue, alongside clinicopathological data, we obtained transcriptomic, immunohistochemical, and microbiome data from both species. We defined the transcriptomic landscape in both species and linked our findings to immunohistochemical, microbiome, and clinical data. Human and dog OMM stratified into two distinctive transcriptional groups, which we defined using a species-independent 41-gene signature. These two subgroups are termed CTLA4-high and MET-high and indicate actionable targets for OMM patients. To guide clinical decision-making, we developed immunohistochemical diagnostic tools that distinguish between transcriptomic subgroups. We found that OMM had conserved transcriptomic subtypes and biological similarity between human and canine OMM, with significant implications for patient classification, treatment, and clinical trial design. © 2025 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Eravacycline improves the efficacy of anti-PD1 immunotherapy via AP1/CCL5 mediated M1 macrophage polarization in melanoma

Screening approved library is a promising and safe strategy to overcome the limitation of low response rate and drug resistance in immunotherapy. Accumulating evidence showed that the application of antibiotics has been considered to reduce the effectiveness of anti-PD1 immunotherapy in tumor treatment, however, in this study, an antibiotic drug (Eravacycline, ERV) was identified to improve the efficacy of anti-PD1 immunotherapy in melanoma through screening approved library. Administration of ERV significantly attenuated melanoma cells growth as well as directly or indirectly benefited M1 macrophage polarization. Meanwhile, ERV treatment significantly induced cellular autophagy via damage of mitochondria, leading to up-regulation of ROS production, subsequently, raised CCL5 secretion through elevation AP1 binding to CCL5 promoter via p38 or JNK1/2 activation. Knockdown of Ccl5 expression attenuated ERV triggered M1 macrophage polarization in melanoma cells. Clinical analysis revealed a positive association between high expression of CCL5 and improved prognosis as well as a favorable anti-PD1 therapy in melanoma patients. As expected, application of ERV improved the efficacy of anti-PD1. Overall, our results approved that ERV enhances the efficacy of anti-PD1 immunotherapy in melanoma by promoting the polarization of M1 macrophages, which provided novel therapeutic strategy for improving the effectiveness of melanoma anti-PD1 immunotherapy.

The Skin Microbiome: A New Key Player in Melanoma, From Onset to Metastatic Stage

The skin microbiome plays a crucial role in maintaining skin health, defending the body against harmful pathogens, and interacting with melanoma. The composition of the skin microbiome can be affected by factors like age, gender, ethnicity, lifestyle, diet, and UV exposure. Certain bacteria like Staphylococcus and Veillonella are important for wound healing, while Cutibacterium acnes can play a role in dermatoses. UV radiation alters the skin microbiome, originates a "UV-resistome" and can lead to skin cancer initiation. Specifically, Staphylococcus epidermidis has shown protective effects against skin cancer, whereas Cutibacterium acnes can induce apoptosis in melanocytes postirradiation. The microbiome also interacts with melanoma treatment, affecting responses to immune checkpoint inhibitors. Strategies like bacteriotherapy, involving the manipulation of the gut microbiome but also the skin microbiome (with the gut-skin axis or through topical treatment) could improve treatment outcomes and show promise in melanoma therapy. Understanding the complex interplay between the skin microbiome, UV exposure, and melanoma development is crucial for developing personalized therapeutic approaches. Investigation into the skin microbiome and its potential role in melanoma progression continues to be an exciting area of research with implications for future therapeutic interventions.

Unlocking the Microbial Symphony: The Interplay of Human Microbiota in Cancer Immunotherapy Response

INTRODUCTION

The emergence of cancer immunotherapy has revolutionized cancer treatment, offering remarkable outcomes for patients across various malignancies. However, the heterogeneous response to immunotherapy underscores the necessity of understanding additional factors influencing treatment efficacy. Among these factors, the human microbiota has garnered significant attention for its potential role in modulating immune response. Body: This review explores the intricate relationship between the human microbiota and cancer immunotherapy, highlighting recent advances and potential mechanisms underlying microbial influence on treatment outcomes.

CONCLUSION

Insights into the microbiome's impact on immunotherapy response not only deepen our understanding of cancer pathogenesis but also hold promise for personalized therapeutic strategies aimed at optimizing patient outcomes.

Emerging insights into the gut microbiota as a key regulator of immunity and response to immunotherapy in hepatocellular carcinoma

The gut microbiota, a complex microbial ecosystem closely connected to the liver via the portal vein, has emerged as a critical regulator of liver health and disease. Numerous studies have underscored its role in the onset and progression of liver disorders, including alcoholic liver disease, metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction-associated steatohepatitis (MASH), liver fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). This review provides a comprehensive overview of current insights into the influence of the gut microbiota on HCC progression, particularly its effects on immune cells within the HCC tumor microenvironment (TME). Furthermore, we explore the potential of gut microbiota-targeted interventions, such as antibiotics, probiotics, prebiotics, and fecal microbiota transplantation (FMT), to modulate the immune response and improve outcomes of immunotherapy in HCC. By synthesizing insights from recent studies, this review aims to highlight microbiota-based strategies that may enhance immunotherapy outcomes, advancing personalized approaches in HCC treatment.

Emerging insights into the impact of systemic metabolic changes on tumor-immune interactions

Tumors are inherently embedded in systemic physiology, which contributes metabolites, signaling molecules, and immune cells to the tumor microenvironment. As a result, any systemic change to host metabolism can impact tumor progression and response to therapy. In this review, we explore how factors that affect metabolic health, such as diet, obesity, and exercise, influence the interplay between cancer and immune cells that reside within tumors. We also examine how metabolic diseases influence cancer progression, metastasis, and treatment. Finally, we consider how metabolic interventions can be deployed to improve immunotherapy. The overall goal is to highlight how metabolic heterogeneity in the human population shapes the immune response to cancer.

Threading the Needle: Navigating Novel Immunotherapeutics in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal malignancy with a poor prognosis. Currently, chemotherapy is the only option for most patients with advanced-stage PDAC. Further, conventional immunotherapies and targeted therapies improve survival outcomes only in rare PDAC patient subgroups. To date, combinatory immunotherapeutic strategies to overcome the immune-hostile PDAC tumor microenvironment (TME) have resulted in limited efficacy in clinical studies. However, efforts are ongoing to develop new treatment strategies for patients with PDAC with the evolving knowledge of the TME, molecular characterization, and immune resistance mechanisms. Further, the growing arsenal of various immunotherapeutic agents, including novel classes of immune checkpoint inhibitors and oncolytic, chimeric antigen receptor T cell, and vaccine therapies, reinforces these efforts. This review will focus on the place of immunotherapy and future possible strategies in PDAC.

Methyl-esterification, degree of polymerization and ∆4,5-unsaturation of galacturonic acid oligosaccharides as determinants of immunomodulation

In recent years, immunomodulation by pectin and pectin-derived galacturonic acid oligosaccharides has been the subject of wide-spread scientific research due to the potential of different pectin structures as bioactive biomolecules. Yet, gaps remain in understanding the structure-dependent immunomodulation of galacturonic acid. This study describes in vitro immunomodulatory effects of well-characterized galacturonic acid oligosaccharides. Both methyl-esterified and non-methyl-esterified galacturonic acid oligosaccharides with a saturated non-reducing end (degree of polymerization 1-10) significantly induced cytokine production by THP-1 macrophages and directly activated TLR2 and TLR4 in transfected HEK-293 cells, even when accounting for minor endotoxin contamination. In contrast, both methyl-esterified and non-methyl-esterified galacturonic acid oligosaccharides with a Δ4,5-unsaturated non-reducing end (degree of polymerization 1-7) did not activate TLR2 and TLR4 and led to significantly reduced cytokine production (p < 0.05), suggesting Δ4,5-(un)saturation as a pivotal factor for immunomodulation by galacturonic acid oligosaccharides. Exposure to non-methyl-esterified saturated galacturonic acid oligosaccharides resulted in significantly lower TNF-α production, IL-1β production and TLR4 activation (p < 0.05) compared to methyl-esterified saturated galacturonic acid oligosaccharides, while IL-10 production and TLR2 activation remained unchanged. These findings establish galacturonic acid oligosaccharides as versatile immunomodulators with TLR2 and TLR4 binding capacity, fit for different immunomodulatory applications depending on their structural characteristics.

The gut microbiome and cancer response to immune checkpoint inhibitors

Immune checkpoint inhibitors (ICIs) are widely used for cancer immunotherapy, yet only a fraction of patients respond. Remarkably, gut bacteria impact the efficacy of ICIs in fighting tumors outside of the gut. Certain strains of commensal gut bacteria promote antitumor responses to ICIs in a variety of preclinical mouse tumor models. Patients with cancer who respond to ICIs have a different microbiome compared with that of patients who don't respond. Fecal microbiota transplants (FMTs) from patients into mice phenocopy the patient tumor responses: FMTs from responders promote response to ICIs, whereas FMTs from nonresponders do not promote a response. In patients, FMTs from patients who have had a complete response to ICIs can overcome resistance in patients who progress on treatment. However, the responses to FMTs are variable. Though emerging studies indicate that gut bacteria can promote antitumor immunity in the absence of ICIs, this Review will focus on studies that demonstrate relationships between the gut microbiome and response to ICIs. We will explore studies investigating which bacteria promote response to ICIs in preclinical models, which bacteria are associated with response in patients with cancer receiving ICIs, the mechanisms by which gut bacteria promote antitumor immunity, and how microbiome-based therapies can be translated to the clinic.

Dietary auxin may help patients to fight cancer

The phytohormone auxin (indole-3-acetic acid; IAA) increases the efficacy of cancer treatment. IAA is a universal molecule, being produced by bacteria, fungi, and plants. Therefore, incorporating IAA-rich products derived from microbes or plants, such as yoghurt, probiotics, microgreens, and fresh carrots into the diet may be promising for disease management.

Static and dynamic in vitro colonic models reveal the spatiotemporal production of flavan-3-ol catabolites

Flavan-3-ols are the most found flavonoid compounds in the human diet. Polymeric and monomeric flavan-3-ols reach the colonic region intact, where the gut microbiota utilizes them as substrates. In this research work, we investigated the pattern of colonic metabolites associated with flavan-3-ols, conducting a comprehensive analysis that combined (un)targeted metabolomics and in vitro colonic models. Firstly, the proposed flavan-3-ol metabolic pathway was investigated in-depth using a static in vitro model inoculated with different fecal donors. An apple, (-)-epicatechin, and procyanidin C1 were employed as feeding conditions. Small phenolic acids, such as phenylpropanoic acid and 3,4-dihydroxybenzoic acid, were positively associated with the apple feeding condition. In contrast, 5-(3',4'-dihydroxyphenyl)-γ-valerolactone and other specific early intermediates like phenylvaleric acids were positively associated with (-)-epicatechin. Secondly, by employing a dynamic in vitro simulator model of the human digestion system (SHIME), we reconstructed the flavan-3-ol metabolic pathway regionally. In the proximal colon region, we localized catabolites, such as 5-(3',4'-dihydroxyphenyl)-γ-valerolactone, while in the distal region, we identified mainly small phenolics. Combining static and dynamic in vitro models, we observed differences in the release of flavan-3-ol catabolites, influenced by both the food structure (isolated compounds and a food matrix) and the colonic region. This study sheds light on the colonic catabolism of one of the main dietary (poly)phenols and localizes microbial metabolites.

Gut microbiota interact with breast cancer therapeutics to modulate efficacy

The gut microbiome, or the community of microorganisms residing in the gastrointestinal tract, has emerged as an important factor in breast cancer etiology and treatment. Specifically, the impact of gut bacterial populations on breast cancer therapeutic outcomes is an emerging area of research. The microbiota's role in modifying the pharmacokinetics of chemotherapy and endocrine-targeting therapies can alter drug efficacy and toxicity profiles. In addition, the gut microbiome's capacity to regulate systemic inflammation and immune responses may influence the effectiveness of both conventional and immunotherapeutic strategies for the treatment of breast cancer. Overall, while the bidirectional interactions between the gut microbiome and breast cancer therapies are still being studied, its impact is increasingly recognized. Future research may provide more definitive insights and help develop personalized therapeutic strategies to harness the microbiome to improve breast cancer treatment outcomes.

Dietary counselling to increase soluble fibre in patients with gynaecological cancers undergoing pelvic radiotherapy: A feasibility study

BACKGROUND

This study aimed to determine the feasibility of increasing soluble fibre intake via dietary counselling to improve gastrointestinal toxicity and quality of life in patients with gynaecological cancers undergoing pelvic radiotherapy without adverse consequences on radiation treatment (RT) delivery accuracy.

METHODS

A single-arm, single-centre intervention feasibility trial included patients with gynaecological cancers undergoing pelvic RT ± chemotherapy at a tertiary hospital. Participants were provided weekly dietary counselling over the duration of their RT (5-6 weeks) to increase soluble fibre intake incrementally each week. Stakeholder surveys were also completed.

RESULTS

In total, 9 of 14 eligible patients participated (55 years old [SD 13.2], diagnosis: cervical [n = 3], endometrial/uterine [n = 5] and vaginal [n = 1]), with the majority categorised as low fibre consumers at baseline (n = 6). On average, soluble fibre intake increased by 150% throughout treatment. There were no adverse events or major adjustments required for RT delivery. There were improving trends in the functional subset identified. Results may be confounded by the sample size resulting from limited eligibility (n = 14) and a high attrition rate (n = 4).

CONCLUSIONS

Most participants successfully increased their soluble fibre intake throughout treatment, without significant adverse events noted for RT delivery accuracy. These results provide preliminary data to calculate the sample size required to produce meaningful effect sizes. However, this study highlighted challenges in participant recruitment and retention, with limited organisational support and perceived compatibility.

Gut-X axis

Recent advances in understanding the modulatory functions of gut and gut microbiota on human diseases facilitated our focused attention on the contribution of the gut to the pathophysiological alterations of many extraintestinal organs, including the liver, heart, brain, lungs, kidneys, bone, skin, reproductive, and endocrine systems. In this review, we applied the "gut-X axis" concept to describe the linkages between the gut and other organs and discussed the latest findings related to the "gut-X axis," including the underlying modulatory mechanisms and potential clinical intervention strategies.

The gut microbiome modulate response to immunotherapy in cancer

Gut microbiota have been reported to play an important role in the occurrence and development of malignant tumors. Currently, clinical studies have identified specific gut microbiota and its metabolites associated with efficacy of immunotherapy in multiple types of cancers. Preclinical investigations have elucidated that gut microbiota modulate the antitumor immunity and affect the efficacy of cancer immunotherapy. Certain microbiota and its metabolites may favorably remodel the tumor microenvironment by engaging innate and/or adaptive immune cells. Understanding how the gut microbiome interacts with cancer immunotherapy opens new avenues for improving treatment strategies. Fecal microbial transplants, probiotics, dietary interventions, and other strategies targeting the microbiota have shown promise in preclinical studies to enhance the immunotherapy. Ongoing clinical trials are evaluating these approaches. This review presents the recent advancements in understanding the dynamic interplay among the host immunity, the microbiome, and cancer immunotherapy, as well as strategies for modulating the microbiome, with a view to translating into clinical applications.

Tumor Microenvironment-Responsive Nanoparticles Enhance IDO1 Blockade Immunotherapy by Remodeling Metabolic Immunosuppression

The clinical efficacy of immune checkpoint blockade (ICB) therapy is significantly compromised in the metabolically disordered tumor microenvironment (TME), posing a formidable challenge that cannot be ignored in current antitumor strategies. In this study, TME-responsive nanoparticles (HMP1G NPs) loaded with 1-methyltryptophan (1-MT; an indoleamine 2,3-dioxygenase 1 [IDO1] inhibitor,) and S-nitrosoglutathione (GSNO; a nitric oxide donor) is developed to enhance the therapeutic efficacy of 1-MT-mediated ICB. The HMP1G NPs responded to H+ and glutathione in the TME, releasing Mn2+, GSNO, and 1-MT. The released Mn2+ catalyzed the production of abundant reactive oxygen species and nitric oxide from hydrogen peroxide and GSNO, and the generated nitric oxide, synergistically with 1-MT, inhibited the accumulation of kynurenine mediated by IDO1 in the tumor. Mechanistically, HMP1G NPs downregulated tumor cell-derived IDO1 via the aryl hydrocarbon receptor/signal transducer and activator of transcription 3/interleukin signaling axis to improve kynurenine/tryptophan metabolism and immunosuppression. In a murine breast cancer model, treatment with HMP1G NPs elicited effective antitumor immunity and enhanced survival outcomes. This study highlights a novel nano-platform that simultaneously improves metabolism and enhances ICB efficacy to achieve a new and efficient antitumor strategy.

Effects of yeast culture on growth performance, antioxidant capacity, immune function, and intestinal microbiota structure in Simmental beef cattle

Introduction

As functional feed additives, yeast cultures have been applied in animal husbandry and shown a wide range of good efficacy. This paper aimed to evaluate the effects of yeast culture (YC) on the growth performance, antioxidant capacity, immune function, and intestinal microbiota structure in beef cattle.

Methods

Forty Simmental bulls were randomly divided into two groups, including the control group fed with Total mixed ration (TMR) and YC group fed with TMR supplemented with 2% YC, for 60 days. Serum samples were collected on the 1st, 30th, and 60th days, respectively, while feces 3 days before the end of the test.

Results

Results showed that YC addition significantly elevated average daily gain and reduced feed to weight ratio of beef cattle. The enzyme activities of total superoxide dismutase, total antioxidant capacity, and glutathione peroxidase in the serum in YC group obviously increased, while the malondialdehyde content distinctly decreased. Furthermore, YC feeding significantly enhanced the immunoglobulin G (IgG), IgA, IgM levels, lysozyme content, alkaline phosphatase activity, as well as the contents of interleukin-1β (IL-1β), IL-6, and interferon-γ in the cattle serum. The Shannon and Observed species indexes of fecal samples in YC group were remarkably higher than those in the control group, with the former group exhibiting a significant increase in the relative abundance of Paraprevotellace_CF231 and Peptostreptococcaceae_Clostridium at the genus level, while the relative abundance of Spirochaetaceae_Treponema decreased significantly. Moreover, the abundance of Clostridium and CF231 was positively associated with the levels of serum antioxidant capacity and immune function indicator contents.

Discussion

In conclusion, YC could obviously improve the growth performance, antioxidant capacity, immune function, and intestinal microbiota structure in Simmental beef cattle. These results provide a theoretical basis for the clinical application of such yeast fermented preparations in beef cattle husbandry.

Functional regulation of cytotoxic T cells by gut microbial metabolites

Metabolites from gut microbes have a wide range of functions within the host body. One important function of these metabolites is to either positively or negatively control CD8+ cytotoxic T lymphocytes (CTLs), which can kill cancer and virus-infected cells. In healthy conditions, gut microbes produce a mixture of metabolites that promote CTL activity but also suppress excessive inflammatory responses. However, gut microbial dysbiosis occurs in patients with cancer, and this leads to changes in the production of gut microbial metabolites that can suppress CTL activity, promote inflammatory responses, and/or aid cancer growth. Decreased levels of CTL-promoting metabolites such as short-chain fatty acids, indole metabolites and polyamines but increased levels of CTL-suppressing metabolites, such as certain bile acids along with oncogenic metabolites, have been observed in patients with cancer. This review summarizes the altered production of major microbial metabolites in patients with cancer and discusses the impact of these changes on anti-cancer CTL responses.

The impact of dietary fiber on colorectal cancer patients based on machine learning

Objective

This study aimed to evaluate the impact of enteral nutrition with dietary fiber on patients undergoing laparoscopic colorectal cancer (CRC) surgery.

Methods

Between January 2023 and August 2024, 164 CRC patients were randomly assigned to two groups at our hospital. The control group received standard nutritional intervention, while the observation group received enteral nutritional support containing dietary fiber. Both groups were subjected to intervention and continuously observed until the 14th postoperative day. An observational analysis assessed the impact of dietary fiber intake on postoperative nutritional status in CRC patients. The study compared infection stress index, inflammatory factors, nutritional status, intestinal function recovery, and complication incidence between groups. Additionally, four machine learning models-Logistic Regression (LR), Random Forest (RF), Neural Network (NN), and Support Vector Machine (SVM)-were developed based on nutritional and clinical indicators.

Results

In the observation group, levels of procalcitonin (PCT), beta-endorphin (β-EP), C-reactive protein (CRP), interleukin-1 (IL-1), interleukin-8 (IL-8), and tumor necrosis factor-alpha (TNF-α) were significantly lower compared to the control group (p < 0.01). Conversely, levels of albumin (ALB), hemoglobin (HB), transferrin (TRF), and prealbumin (PAB) in the observation group were significantly higher than those in the control group (p < 0.01). Furthermore, LR, RF, NN, and SVM models can effectively predict the effects of dietary fiber on the immune function and inflammatory response of postoperative CRC patients, with the NN model performing the best. Through the screening of machine learning models, four key predictors for CRC patients were identified: PCT, PAB, ALB, and IL-1.

Conclusion

Postoperative dietary fiber administration in colorectal cancer enhances immune function, reduces disease-related inflammation, and inhibits tumor proliferation. Machine learning-based CRC prediction models hold clinical value.

A yeast-based oral therapeutic delivers immune checkpoint inhibitors to reduce intestinal tumor burden

Engineered probiotics are an emerging platform for in situ delivery of therapeutics to the gut. Herein, we developed an orally administered, yeast-based therapeutic delivery system to deliver next-generation immune checkpoint inhibitor (ICI) proteins directly to gastrointestinal tumors. We engineered Saccharomyces cerevisiae var. boulardii (Sb), a probiotic yeast with high genetic tractability and innate anticancer activity, to secrete "miniature" antibody variants that target programmed death ligand 1 (Sb_haPD-1). When tested in an ICI-refractory colorectal cancer (CRC) mouse model, Sb_haPD-1 significantly reduced intestinal tumor burden and resulted in significant shifts to the immune cell profile and microbiome composition. This oral therapeutic platform is modular and highly customizable, opening new avenues of targeted drug delivery that can be applied to treat a myriad of gastrointestinal malignancies.

Advances in the understanding and therapeutic manipulation of cancer immune responsiveness: a Society for Immunotherapy of Cancer (SITC) review

Cancer immunotherapy-including immune checkpoint inhibition (ICI) and adoptive cell therapy (ACT)-has become a standard, potentially curative treatment for a subset of advanced solid and liquid tumors. However, most patients with cancer do not benefit from the rapidly evolving improvements in the understanding of principal mechanisms determining cancer immune responsiveness (CIR); including patient-specific genetically determined and acquired factors, as well as intrinsic cancer cell biology. Though CIR is multifactorial, fundamental concepts are emerging that should be considered for the design of novel therapeutic strategies and related clinical studies. Recent advancements as well as novel approaches to address the limitations of current treatments are discussed here, with a specific focus on ICI and ACT.

Effect of a Novel Food Rich in Miraculin on the Intestinal Microbiome of Malnourished Patients with Cancer and Dysgeusia

BACKGROUND/OBJECTIVES

Dysgeusia contributes to malnutrition and worsens the quality of life of patients with cancer. Despite the different strategies, there is no effective treatment for patients suffering from taste disorders provided by the pharmaceutical industry. Therefore, we developed a novel strategy for reducing side effects in cancer patients by providing a novel food supplement with the taste-modifying glycoprotein miraculin, which is approved by the European Union, as an adjuvant to medical-nutritional therapy.

METHODS

A pilot randomized, parallel, triple-blind, and placebo-controlled intervention clinical trial was carried out in which 31 malnourished patients with cancer and dysgeusia receiving antineoplastic treatment were randomized into three arms-standard dose of dried miracle berries (DMBs) (150 mg DMB/tablet), high dose of DMBs (300 mg DMB/tablet), or placebo (300 mg freeze-dried strawberry)-for three months. Patients consumed a DMB or placebo tablet before each main meal (breakfast, lunch, and dinner). Using stool samples from patients with cancer, we analyzed the intestinal microbiome via nanopore methodology.

RESULTS

We detected differences in the relative abundances of genera Phocaeicola and Escherichia depending on the treatment. Nevertheless, only the Solibaculum genus was more abundant in the standard-dose DMB group after 3 months. At the species level, Bacteroides sp. PHL 2737 presented a relatively low abundance in both DMB groups, whereas Vescimonas coprocola presented a relatively high abundance in both treatment groups after 3 months. Furthermore, a standard dose of DMB was positively associated with TNF-α levels and Lachnoclostridium and Mediterraneibacter abundances, and a high dose of DMB was negatively associated with TNF-α levels and the relative abundance of Phocaeicola. Following the administration of a high dose of DMB, a positive correlation was observed between erythrocyte polyunsaturated fatty acids and the presence of Lachnoclostridium and Roseburia. Additionally, a positive association was identified between Phocaeicola and the acetic acid concentration of feces. There was a negative association between the relative abundance of Phocaeicola and taste perception in the high-dose DMB group.

CONCLUSIONS

The combination of DMB intake with nutritional treatment and individualized dietary guidance results in positive changes in the intestinal microbiome of patients with cancer and dysgeusia. Changes observed in the intestinal microbiome might contribute to maintaining an appropriate immune response in cancer patients. As the current pilot study included a limited number of participants, further clinical trials on a larger group of patients are needed to draw robust findings.

Understanding the role of the gut microbiome in solid tumor responses to immune checkpoint inhibitors for personalized therapeutic strategies: a review

Immunotherapy, especially immune checkpoint inhibitor (ICI) therapy, has yielded remarkable outcomes for some patients with solid cancers, but others do not respond to these treatments. Recent research has identified the gut microbiota as a key modulator of immune responses, suggesting that its composition is closely linked to responses to ICI therapy in cancer treatment. As a result, the gut microbiome is gaining attention as a potential biomarker for predicting individual responses to ICI therapy and as a target for enhancing treatment efficacy. In this review, we discuss key findings from human observational studies assessing the effect of antibiotic use prior to ICI therapy on outcomes and identifying specific gut bacteria associated with favorable and unfavorable responses. Moreover, we review studies investigating the possibility of patient outcome prediction using machine learning models based on gut microbiome data before starting ICI therapy and clinical trials exploring whether gut microbiota modulation, for example via fecal microbiota transplantation or live biotherapeutic products, can improve results of ICI therapy in patients with cancer. We also briefly discuss the mechanisms through which the gut microbial-derived products influence immunotherapy effectiveness. Further research is necessary to fully understand the complex interactions between the host, gut microbiota, and immunotherapy and to develop personalized strategies that optimize responses to ICI therapy.

Baseline colitogenicity and acute perturbations of gut microbiota in immunotherapy-related colitis

Immunotherapy-related colitis (irC) frequently emerges as an immune-related adverse event during immune checkpoint inhibitor therapy and is presumably influenced by the gut microbiota. We longitudinally studied microbiomes from 38 ICI-treated cancer patients. We compared 13 ICI-treated subjects who developed irC against 25 ICI-treated subjects who remained irC-free, along with a validation cohort. Leveraging a preclinical mouse model, predisease stools from irC subjects induced greater colitigenicity upon transfer to mice. The microbiota during the first 10 days of irC closely resembled inflammatory bowel disease microbiomes, with reduced diversity, increased Proteobacteria and Veillonella, and decreased Faecalibacterium, which normalized before irC remission. These findings highlight the irC gut microbiota as functionally distinct but phylogenetically similar to non-irC and healthy microbiomes, with the exception of an acute, transient disruption early in irC. We underscore the significance of longitudinal microbiome profiling in developing clinical avenues to detect, monitor, and mitigate irC in ICI therapy cancer patients.

The Relationship Between the Modulation of Intestinal Microbiota and the Response to Immunotherapy in Patients with Cancer

The intestinal microbiota is an important part of the human body, and its composition can affect the effectiveness of immunotherapy. In the last few years, the modulation of intestinal microbiota in order to improve the effectiveness of immunotherapy has become a current topic in the scientific community, but there is a lack of research in this area. In this review, the goal was to analyze the current relevant literature related to the modulation of intestinal microbiota and the effectiveness of immunotherapy in the treatment of cancer. The effects of antibiotics, probiotics, diet, and fecal microbial transplantation were analyzed separately. It was concluded that the use of antibiotics, especially broad-spectrum types or larger quantities, causes dysbiosis of the intestinal microbiota, which can reduce the effectiveness of immunotherapy. While dysbiosis could be repaired by probiotics and thus improve the effectiveness of immunotherapy, the use of commercial probiotics without evidence of intestinal dysbiosis has not yet been sufficiently tested to confirm its safety for cancer for immunotherapy-treated cancer patients. A diet consisting of sufficient amounts of fiber, as well as a diet with higher salt content positively correlates with the success of immunotherapy. Fecal transplantation is a safe and realistic adjuvant option for the treatment of cancer patients with immunotherapy, but more clinical trials are necessary. Modulating the microbiota composition indeed changes the effectiveness of immunotherapy, but in the future, more human studies should be organized to precisely determine the types and procedures of microbiota modulation.

The impact of fibre and prebiotic interventions on outcomes in cancer and haematopoietic stem cell transplantation: A systematic review

BACKGROUND & AIMS

Cancer therapy is associated with a range of toxicities that severely impact patient well-being and a range of clinical outcomes. Dietary fibre/prebiotics characteristically improve the gastrointestinal microenvironment, which consequently elicits beneficial downstream effects that could be relevant to the prevention and management of treatment-related toxicities. Despite the compelling theoretical scientific rationale there has been limited effort to synthesise the available evidence to conclude such scientific underpinning to the clinical use of fibre/prebiotics in cancer patients. Therefore, this systematic review aimed to evaluate the clinical impact of fibre/prebiotic-based interventions on gastrointestinal-side effects; gastrointestinal-microbiome; clinical outcomes; nutrition status and body composition; and quality-of-life in children and adults being treated for cancer or undergoing a haematopoietic stem cell transplant (HSCT).

METHODS

This study was conducted in adherence to PRISMA guidelines, and the protocol was published prospectively with PROSPERO (CRD42022299428). Three databases (MEDLINE (Ovid), CINHAL, EMBASE) were searched from inception to December 2023. All articles were assessed for bias using the Cochrane risk-of-bias tool RoB 2.0 (for RCTs) and ROBINS-I (for non-RCTs).

RESULTS

A total of 9989 de-duplicated records were identified, of these, 14 (paediatrics [n = 1], adults [n = 13]) met the inclusion criteria (randomised controlled trials (RCT) [n = 11], observational or non-RCTs [n = 3]). The risk-of-bias was graded to be serious/high (n = 6); moderate/some concerns (n = 7); low (n = 1). Interventions included prebiotic supplement (n = 8), nutrition supplement/formula with added fibre/prebiotic (n = 3) and dietary modification (n = 3). The dose of fibre intervention ranged from 2.4g to 30g per day. Substantial heterogeneity of target parameters was identified across a range all outcome categories, precluding definitive conclusions.

CONCLUSION

The scientific rationale for fibre/prebiotics-based interventions for the prevention or management of cancer treatment-related toxicities is compelling. However, it is clear that the scientific and clinical field remains disconnected in how to effectively translate this approach to improve cancer outcomes. High-quality intervention studies translatable to clinical practice are now evidently crucial to determine if and how fibre/prebiotics should be used to support people undergoing cancer or HSCT therapy.

Mechanisms of Anti-PD Therapy Resistance in Digestive System Neoplasms

Digestive system neoplasms are highly heterogeneous and exhibit complex resistance mechanisms that render anti-programmed cell death protein (PD) therapies poorly effective. The tumor microenvironment (TME) plays a pivotal role in tumor development, apart from supplying energy for tumor proliferation and impeding the body's anti-tumor immune response, the TME actively facilitates tumor progression and immune escape via diverse pathways, which include the modulation of heritable gene expression alterations and the intricate interplay with the gut microbiota. In this review, we aim to elucidate the mechanisms underlying drug resistance in digestive tumors, focusing on immune-mediated resistance, microbial crosstalk, metabolism, and epigenetics. We will highlight the unique characteristics of each digestive tumor and emphasize the significance of the tumor immune microenvironment (TIME). Furthermore, we will discuss the current therapeutic strategies that hold promise for combination with cancer immune normalization therapies. This review aims to provide a thorough understanding of the resistance mechanisms in digestive tumors and offer insights into potential therapeutic interventions.

Tumor immunology and immunotherapy for endometrial cancer

INTRODUCTION

Recent clinical trials show the efficacy of immune checkpoint inhibitors (ICIs) or a combination of ICI and poly (ADP-ribose) polymerase (PARP) inhibitors for advanced or recurrent endometrial cancer. However, the basis for such treatment effects remains unclear, hindering the advancement of personalized therapy.

AREAS COVERED

This review includes a detailed interpretation of subgroup analysis data from phase III clinical trials for endometrial cancer evaluating the efficacy of chemotherapy plus ICIs (NRG-GY018, RUBY, AtTEnd, KEYNOTE-B21) or chemotherapy plus ICI with/without olaparib (DUO-E). We focused on the relationship between obesity, the effect of PARP inhibitors, and tumor immunity in endometrial cancer, searched for relevant literature published from 2000 to 2024 in PubMed, and conducted a narrative review.

EXPERT OPINION

Chemotherapy plus ICI is appropriate for dMMR. Chemotherapy plus ICI and PARP inhibitor may be appropriate for TP53abn type or serous carcinoma because PARP inhibitor enhances the efficacy of ICI by activating the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) pathway. Obese patients may benefit more from ICIs, and this appears to cause the variation in efficacy between regions/countries. Administration for measurable disease appears important to increase the effect of ICIs. Diet and exercise may also be important factors.

Role of the Microbiome and Diet for Response to Cancer Checkpoint Immunotherapy: A Narrative Review of Clinical Trials

PURPOSE OF REVIEW

The advent of checkpoint immunotherapy has dramatically changed the outcomes for patients with cancer. However, a considerable number of patients have little or no response to therapy. We review recent findings on the connection between the gut microbiota and the immune system, exploring whether this link could enhance the effectiveness of immunotherapy.

RECENT FINDINGS

Clinical studies have reported specific types of bacteria in larger quantities at baseline in responders than in non-responders, especially Akkermansia mucinifila, Ruminococcaceae, Faecalibacterium, and Lachnospiraceae. Following the consumption of a high-fiber diet, bacteria in the gut ferment dietary fiber to short-chain fatty acids (SCFAs), like acetate, propionate, and butyrate. Some of the SCFAs nurture intestinal epithelial cells, and some enter the bloodstream. Here SCFAs can activate DC8 + cytotoxic T-cells to induce cancer cell death. High fiber intake in the diet was associated with a reduced risk of progression or death during checkpoint immunotherapy. Recent findings demonstrate that high-fiber plant-based diets such as the Mediterranean Diet positively influence the gut microbiota whereas antibiotics and proton pump inhibitors can negatively influence outcomes of cancer immunotherapy by changing the gut microbiota. This narrative review provides evidence of an association between types of bacteria and their metabolites and favorable responses to checkpoint immunotherapy. Prospective clinical trials are needed to determine if diet interventions can improve treatment outcomes.

Microbiome research in autoimmune and immune-mediated inflammatory diseases: lessons, advances and unmet needs

The increasing prevalence of autoimmune and immune-mediated diseases (AIMDs) underscores the need to understand environmental factors that contribute to their pathogenesis, with the microbiome emerging as a key player. Despite significant advancements in understanding how the microbiome influences physiological and inflammatory responses, translating these findings into clinical practice remains challenging. This viewpoint reviews the progress and obstacles in microbiome research related to AIMDs, examining molecular techniques that enhance our understanding of microbial contributions to disease. We discuss significant discoveries linking specific taxa and metabolites to diseases such as rheumatoid arthritis, systemic lupus erythematosus and spondyloarthritis, highlighting the role of gut dysbiosis and host-microbiome interactions. Furthermore, we explore the potential of microbiome-based therapeutics, including faecal microbiota transplantation and pharmacomicrobiomics, while addressing the challenges of identifying robust microbial targets. We advocate for integrative, transdisease studies and emphasise the need for diverse cohort research to generalise findings across populations. Understanding the microbiome's role in AIMDs will pave the way for personalised medicine and innovative therapeutic strategies.

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.

Genomic insights into the probiotic potential and genes linked to gallic acid metabolism in Pediococcus pentosaceus MBBL6 isolated from healthy cow milk

Pediococcus pentosaceus is well known for its probiotic properties, including roles in improving health, antimicrobial production, and enhancing fermented food quality. This study aimed to comprehensively analyze the whole genome of P. pentosaceus MBBL6, isolated from healthy cow milk, to assess its probiotic and antimicrobial potentials. P. pentosaceus MBBL6, isolated from a healthy cow milk at BSMRAU dairy farm, Gazipur, Bangladesh, underwent comprehensive genomic analysis, including whole genome sequencing, assembly, annotation, phylogenetic comparison, and assessment of metabolic pathways and secondary metabolites. Antimicrobial efficacy was evaluated through in-vitro and in-vivo studies, alongside in-silico exploration for potential mastitis therapy. We predicted 1,906 genes and 204 SEED sub-systems involved in carbohydrate metabolism and vitamin B complex biosynthesis, with a focus on lactose metabolism in MMBL6. Notably, 43 putative carbohydrate-active enzyme genes, including lysozymes, suggest the ability of MBBL6 for carbohydrate biotransformation and antimicrobial activity. The genome also revealed primary metabolic pathways for arginine and gallic acid metabolism and secondary metabolite gene clusters, including T3PKS and RiPP-like regions. Importantly, two bacteriocin biosynthesis gene clusters namely bovicin_255_variant and penocin_A, were identified in MBBL6. The safety assessment of MBBL6 genome revealed no virulence genes and a low pathogenicity score (0.196 out of 1.0). Several genes related to survival in gastrointestinal tract and colonization were also identified. Furthermore, MBBL6 exhibited susceptibility to a wide range of antibiotics in-vitro, and effectively suppressed mastitis pathogens in an in-vivo mouse mastitis model trial. The observed bacteriocin, particularly bovicin, demonstrated the ability to disrupt the function of an essential protein, Rho factor of mastitis pathogens by blocking transcription termination process. Taken together, our in-depth genomic analysis underscores the metabolic versatility, safety profile, and antimicrobial potential of P. pentosaceus MBBL6, suggesting its promise for applications in therapeutics, bioremediation, and biopreservation.

Insights into the Relationship Between the Gut Microbiome and Immune Checkpoint Inhibitors in Solid Tumors

Immunotherapy with immune checkpoint inhibitors represents a revolutionary approach to the treatment of solid tumors, including malignant melanoma, lung cancer, and gastrointestinal malignancies. Anti-CTLA-4 and anti-PD-1/PDL-1 therapies provide prolonged survival for cancer patients, but their efficacy and safety are highly variable. This review focuses on the crucial role of the gut microbiome in modulating the efficacy and toxicity of immune checkpoint blockade. Studies suggest that the composition of the gut microbiome may influence the response to immunotherapy, with specific bacterial strains able to promote an anti-tumor immune response. On the other hand, dysbiosis may increase the risk of adverse effects, such as immune-mediated colitis. Interventions aimed at modulating the microbiome, including the use of probiotics, prebiotics, fecal microbial transplantation, or dietary modifications, represent promising strategies to increase treatment efficacy and reduce toxicity. The combination of immunotherapy with the microbiome-based strategy opens up new possibilities for personalized treatment. In addition, factors such as physical activity and nutritional supplementation may indirectly influence the gut ecosystem and consequently improve treatment outcomes in refractory patients, leading to enhanced patient responses and prolonged survival.

A whole food, plant-based diet reduces amino acid levels in patients with metastatic breast cancer

BACKGROUND

Amino acids are critical to tumor survival. Tumors can acquire amino acids from the surrounding microenvironment, including the serum. Limiting dietary amino acids is suggested to influence their serum levels. Further, a plant-based diet is reported to contain fewer amino acids than an animal-based diet. The extent to which a plant-based diet lowers the serum levels of amino acids in patients with cancer is unclear.

METHODS

Patients with metastatic breast cancer (n = 17) were enrolled in a clinical trial with an ad libitum whole food, plant-based diet for 8 weeks without calorie or portion restriction. Dietary changes by participants were monitored using a three-day food record. Serum was collected from participants at baseline and 8 weeks. Food records and serum were analyzed for metabolic changes.

RESULTS

We found that a whole food, plant-based diet resulted in a lower intake of calories, fat, and amino acids and higher levels of fiber. Additionally, body weight, serum insulin, and IGF were reduced in participants. The diet contained lower levels of essential and non-essential amino acids, except for arginine (glutamine and asparagine were not measured). Importantly, the lowered dietary intake of amino acids translated to reduced serum levels of amino acids in participants (5/9 essential amino acids; 4/11 non-essential amino acids).

CONCLUSIONS

These findings provide a tractable approach to limiting amino acid levels in persons with cancer. This data lays a foundation for studying the relationship between amino acids in patients and tumor progression. Further, a whole-food, plant-based diet has the potential to synergize with cancer therapies that exploit metabolic vulnerabilities.

TRIAL REGISTRATION

The clinical trial was registered with ClinicalTrials.gov identifier NCT03045289 on 2017-02-07.

Bee Pollen as a Source of Biopharmaceuticals for Neurodegeneration and Cancer Research: A Scoping Review and Translational Prospects

Bee Pollen (BP) has many advantageous properties relying on its multitargeting potential, a new tendency in managing many challenging illnesses. In cancer and neurodegeneration, the multiple effects of BP could be of unequaled importance and need further investigation. Although still limited, available data interestingly spotlights some floral sources with promising activities in line with this investigation. Adopting scoping review methodology, we have identified many crucial bioactivities that are widely recognized to individual BP compounds but remain completely untapped in this valuable bee cocktail. A wide range of these compounds have been recently found to be endowed with great potential in modulating pivotal processes in neurodegeneration and cancer pathophysiology. In addition, some ubiquitous BP compounds have only been recently isolated, while the number of studied BPs remains extremely limited compared to the endless pool of plant species worldwide. We have also elucidated that clinical profits from these promising perspectives are still impeded by challenging hurdles such as limited bioavailability of the studied phytocompounds, diversity and lack of phytochemical standardization of BP, and the difficulty of selective targeting in some pathophysiological mechanisms. We finally present interesting insights to guide future research and pave the way for urgently needed and simplified clinical investigations.

Guilds as guides for health vs. disease

In a recent Cell paper, Wu et al. identified microbiome guilds based on bacterial co-occurrence among type 2 diabetes patients. Two competing guilds, associated with high-fiber vs. control diets, correlated with healthy biomarkers. The potential of this approach was further verified across 15 diseases in 26 studies.

Diet and Immune Effects Trial (DIET)- a randomized, double-blinded dietary intervention study in patients with melanoma receiving immunotherapy

BACKGROUND

Gut microbiome modulation is a promising strategy for enhancing the response to immune checkpoint blockade (ICB). Fecal microbiota transplant studies have shown positive signals of improved outcomes in both ICB-naïve and refractory melanoma patients; however, this strategy is challenging to scale. Diet is a key determinant of the gut microbiota, and we have previously shown that (a) habitual high dietary fiber intake is associated with an improved response to ICB and (b) fiber manipulation in mice impacts antitumor immunity. We recently demonstrated the feasibility of a controlled high-fiber dietary intervention (HFDI) conducted in melanoma survivors with excellent compliance and tolerance. Building on this, we are now conducting a phase II randomized trial of HFDI versus a healthy control diet in melanoma patients receiving ICB.

METHODS

This is a randomized, double-blind, fully controlled feeding study that will enroll 45 melanoma patients starting standard-of-care (SOC) ICB in three settings: adjuvant, neoadjuvant, and unresectable. Patients are randomized 2:1 to the HFDI (target fiber 50 g/day from whole foods) or healthy control diet (target fiber 20 g/day) stratified by BMI and cohort. All meals are prepared by the MD Anderson Bionutrition Core and are isocaloric and macronutrient-controlled. The intervention includes a 1-week equilibration period and then up to 11 weeks of diet intervention. Longitudinal blood, stool and tumor tissue (if available) are collected throughout the trial and at 12 weeks post intervention.

DISCUSSION

This DIET study is the first fully controlled feeding study among cancer patients who are actively receiving immunotherapy. The goal of the current study is to establish the effects of dietary intervention on the structure and function of the gut microbiome in patients with melanoma treated with SOC immunotherapies. The secondary endpoints include changes in systemic and tumor immunity, changes in the metabolic profile, quality of life, symptoms, disease response and immunotherapy toxicity.

TRIAL REGISTRATION

This protocol is registered with the U.S. National Institutes of Health trial registry, ClinicalTrials.gov, under the identifier NCT04645680. First posted 2020-11-27; last verified 2024-06.

Diet and Cancer Metabolism

Diet and exercise are modifiable lifestyle factors known to have a major influence on metabolism. Clinical practice addresses diseases of altered metabolism such as diabetes or hypertension by altering these factors. Despite enormous public interest, there are limited defined diet and exercise regimens for cancer patients. Nevertheless, the molecular basis of cancer has converged over the past 15 years on an essential role for altered metabolism in cancer. However, our understanding of the molecular mechanisms that underlie the impact of diet and exercise on cancer metabolism is in its very early stages. In this work, we propose conceptual frameworks for understanding the consequences of diet and exercise on cancer cell metabolism and tumor biology and also highlight recent developments. By advancing our mechanistic understanding, we also discuss actionable ways that such interventions could eventually reach the mainstay of both medical oncology and cancer control and prevention.

The role of the gut microbiome in modulating immunotherapy efficacy in colorectal cancer

This systematic literature review and meta-analysis provide an overview of the critical role of gut microbiota in modulating the efficacy of immunotherapy for colorectal cancer. Gut microbes influence host immune responses through multiple mechanisms including modulation of immune cell activity, metabolite action, and immune tolerance. The ability of specific gut microbes to improve the efficacy of immune checkpoint inhibitors has been linked to their ability to improve gut barrier function, modulate immune cell activity, and produce key immunomodulatory metabolites such as short-chain fatty acids. In addition, the composition and diversity of the gut microbiota are strongly associated with the efficacy of immunotherapies, demonstrating the potential to improve therapeutic response by modifying the gut microbiota. This paper also discusses the prospect of manipulating the gut microbiota through strategies such as fecal microbial transplantation, probiotic supplementation, and dietary modifications to optimize the efficacy of immunotherapy.

Beyond the Microbiome: The Role of the Metabolome and Diet in Antitumor Immunity

Microbiome-derived or -modulated metabolites (short-chain fatty acids, bile acids, and amino acids) could mediate antitumor immunity. Diet offers an actionable route for manipulating both the microbiome and the metabolome. Diet- and microbiome-directed trials with robust translational correlates are eagerly awaited.

Frequent intake of high fiber and probiotic diets lowers risks associated with atopic dermatitis and house dust mite allergy: a cross-sequential study of young Chinese adults from Singapore and Malaysia

PURPOSE

Dietary fiber intake may influence the risk and severity of atopic dermatitis (AD), a common chronic allergic skin condition. This cross-sequential study investigated the association between dietary fiber intake and various characteristics of AD, including house dust mites (HDM) allergy and dry skin, in 13,561 young Chinese adults (mean years = 22.51, SD ± 5.90) from Singapore and Malaysia.

METHODS

Dietary habits were assessed using a validated semi-quantitative, investigator-administered food frequency questionnaire from the International Study of Asthma and Allergies in Childhood. We derived an amount-based dietary index to estimate fiber intake while studying its correlation with probiotic drinks intake. AD status was determined by skin prick tests for HDM and symptomatic histories of eczema. Multivariable logistic regression analysis, adjusting for demographic, genetic predisposition, body mass index and lifestyle factors, and synergy factor analysis were used to explore the association and interaction of dietary factors on disease outcomes.

RESULTS

High fiber intake (approximately 98.25 g/serving/week) significantly lowered the associated risks for HDM allergy (Adjusted Odds Ratio [AOR]: 0.895; 95% Confidence Intervals [CI]: 0.810-0.989; adjusted p-value < 0.05) and AD (AOR: 0.831; 95% CI: 0.717-0.963; adjusted p-value < 0.05), but not dry skin. While probiotic intake was not associated with AD, it was significantly correlated with fiber intake (R2 = 0.324, p-value < 0.0001). Among those frequently consuming probiotics, moderate fiber intake sufficiently lowered the AD risk (AOR: 0.717; 95% CI: 0.584-0.881; adjusted p-value < 0.01). Moreover, a fibre-rich diet independently mitigated risks associated with high intake of fats, saturated fats, and protein.

CONCLUSION

A high-fiber diet is associated with AD and HDM allergy. Moderate-to-high fiber intake, particularly in conjunction with probiotics, may further mitigate AD risks.

Gut microbiota as a biomarker and modulator of anti-tumor immunotherapy outcomes

Although immune-checkpoint inhibitors (ICIs) have significantly improved cancer treatment, their effectiveness is limited by primary or acquired resistance in many patients. The gut microbiota, through its production of metabolites and regulation of immune cell functions, plays a vital role in maintaining immune balance and influencing the response to cancer immunotherapies. This review highlights evidence linking specific gut microbial characteristics to increased therapeutic efficacy in a variety of cancers, such as gastrointestinal cancers, melanoma, lung cancer, urinary system cancers, and reproductive system cancers, suggesting the gut microbiota's potential as a predictive biomarker for ICI responsiveness. It also explores the possibility of enhancing ICI effectiveness through fecal microbiota transplantation, probiotics, prebiotics, synbiotics, postbiotics, and dietary modifications. Moreover, the review underscores the need for extensive randomized controlled trials to confirm the gut microbiota's predictive value and to establish guidelines for microbiota-targeted interventions in immunotherapy. In summary, the article suggests that a balanced gut microbiota is key to maximizing immunotherapy benefits and calls for further research to optimize microbiota modulation strategies for cancer treatment. It advocates for a deeper comprehension of the complex interactions between gut microbiota, host immunity, and cancer therapy, aiming for more personalized and effective treatment options.

Prevotellaceae Modulates Colorectal Cancer Immune Microenvironment to Assist Anti-PD-L1 Immunotherapy

Background/Aims

Colorectal cancer (CRC) stands as the third most prevalent cancer on a global scale. In recent years, immunotherapy, such as anti-PD-L1 treatment, has demonstrated promising therapeutic outcomes in CRC. However, studies have suggested that intestinal microbiota may influence the efficacy of anti-PD-L1 immunotherapy. This study aimed to investigate the linkage between intestinal bacteria and anti-PD-L1 therapy.

Materials and Methods

Bioinformatics analysis was employed to study the correlation between the intestinal microbiota of CRC patients and immune infiltration. The study delved into the relationship between Prevotellaceae and immune-related genes in CRC. Mouse experiments were conducted to validate the association between Prevotellaceae abundance and the efficacy of anti-PD-L1 tumor treatment. Prevotellaceae abundance in mouse feces was assayed by 16S sequencing. Flow cytometry was utilized to assay immune cell infiltration in patient tumor tissues, while western blot and quantitative polymerase chain reaction (qPCR) assays measured IFN-γ, IL-2, and PD-L1 levels in tumor tissues.

Results

The high immune cell infiltration group demonstrated reduced tumor purity when compared with the group displaying low immune cell infiltration. Substantial variances were discerned in the Stromal Score, Immune Score, ESTIMATE Score, and Tumor Purity among the 3 distinct subtypes. The community evenness in the gut microbiota of CRC patients from cluster 2 and cluster 3 subtypes displayed significant differences. Members of the Prevotellaceae family were significantly enriched in the gut microbiota of cluster 3 subtype patients. In vivo experiments ascertained the supportive role of Prevotellaceae in anti-PD-L1 immunotherapy.

Conclusion

The facilitating effect of Prevotellaceae on anti-PD-L1 treatment was demonstrated in CRC. The findings suggest that elevating Prevotellaceae abundance may offer a new direction for assisting in CRC immunotherapy and provide a foundation for devising more effective CRC immunotherapeutic strategies.

asmbPLS: biomarker identification and patient survival prediction with multi-omics data

Introduction

With the advancement of high-throughput studies, an increasing wealth of high-dimensional multi-omics data is being collected from the same patient cohort. However, leveraging this multi-omics data to predict survival outcomes poses a significant challenge due to its complex structure.

Methods

In this article, we present a novel approach, the Adaptive Sparse Multi-Block Partial Least Squares (asmbPLS) Regression model, which introduces a dynamic assignment of penalty factors to distinct blocks within various PLS components, facilitating effective feature selection and prediction.

Results

We compared the proposed method with several state-of-the-art algorithms encompassing prediction performance, feature selection and computation efficiency. We conducted comprehensive evaluations using both simulated data with various scenarios and a real dataset from the melanoma patients to validate the effectiveness and efficiency of the asmbPLS method. Additionally, we applied the lung squamous cell carcinoma (LUSC) dataset from The Cancer Genome Atlas (TCGA) to further assess the feature selection capability of asmbPLS.

Discussion

The inherent nature of asmbPLS imparts it with higher sensitivity in feature selection compared to other methods. Furthermore, an R package called asmbPLS implementing this method is made publicly available.

Oncolytic Virotherapies and Adjuvant Gut Microbiome Therapeutics to Enhance Efficacy Against Malignant Gliomas

Glioblastoma (GBM) is the most prevalent malignant brain tumor. Current standard-of-care treatments offer limited benefits for patient survival. Virotherapy is emerging as a novel strategy to use oncolytic viruses (OVs) for the treatment of GBM. These engineered and non-engineered viruses infect and lyse cancer cells, causing tumor destruction without harming healthy cells. Recent advances in genetic modifications to OVs have helped improve their targeting capabilities and introduce therapeutic genes, broadening the therapeutic window and minimizing potential side effects. The efficacy of oncolytic virotherapy can be enhanced by combining it with other treatments such as immunotherapy, chemotherapy, or radiation. Recent studies suggest that manipulating the gut microbiome to enhance immune responses helps improve the therapeutic efficacy of the OVs. This narrative review intends to explore OVs and their role against solid tumors, especially GBM while emphasizing the latest technologies used to enhance and improve its therapeutic and clinical responses.

Dietary pattern and the corresponding gut microbiome in response to immunotherapy in Thai patients with advanced non-small cell lung cancer (NSCLC)

Gut microbiota is considered a key player modulating the response to immune checkpoint inhibitors (ICI) in cancer. The effects of dietary pattern on this interaction is not well-studied. A prospective multicenter cohort of 95 patients with advanced non-small cell lung cancer (NSCLC) undergoing ICI therapy were enrolled. Stool shotgun metagenomic sequencing was performed. Three-day dietary patterns before ICI were assessed. Patients were categorized as hyperprogressive disease (HPD) if they exhibited a time to treatment failure of less than 2 months. All others were categorized as non-hyperprogressive disease (non-HPD). The correlation between dietary patterns, gut microbiome, and response to ICI therapy was analyzed. In the multivariate analysis, a high abundance of Firmicutes unclassified and the Ruminococcaceae family correlated with a significantly diminished progression-free survival (PFS) with an HR of 2.40 [P = 0.006] and 4.30 [P = 0.005], respectively. More specifically, within the subset of NSCLC patients treated solely with ICI therapy, a high abundance of Intestinimonas and the Enterobacteriaceae family were associated with substantially reduced PFS with an HR of 2.61 [P = 0.02] and HR 3.34 [P = 0.005], respectively. In our comprehensive dietary pattern analysis, the HPD group showed increased consumption of cholesterol, sodium, and fats beyond recommended levels compared to the non-HPD group. This group also displayed a tendency towards higher food pattern scores characterized by a high intake of fat and dairy products. Our study revealed a distinct association between the gut microbiome composition and treatment outcomes. The overall composition of diet might be related to ICI therapeutic outcomes.

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.