Fecal microbiota transplant promotes response in immunotherapy-refractory melanoma patients

From chaos to order: optimizing fecal microbiota transplantation for enhanced immune checkpoint inhibitors efficacy

The integration of fecal microbiota transplantation (FMT) with immune checkpoint inhibitors (ICIs) presents a promising approach for enhancing cancer treatment efficacy and overcoming therapeutic resistance. This review critically examines the controversial effects of FMT on ICIs outcomes and elucidates the underlying mechanisms. We investigate how FMT modulates gut microbiota composition, microbial metabolite profiles, and the tumor microenvironment, thereby influencing ICIs effectiveness. Key factors influencing FMT efficacy, including donor selection criteria, recipient characteristics, and administration protocols, are comprehensively discussed. The review delineates strategies for optimizing FMT formulations and systematically monitoring post-transplant microbiome dynamics. Through a comprehensive synthesis of evidence from clinical trials and preclinical studies, we elucidate the potential benefits and challenges of combining FMT with ICIs across diverse cancer types. While some studies report improved outcomes, others indicate no benefit or potential adverse effects, emphasizing the complexity of host-microbiome interactions in cancer immunotherapy. We outline critical research directions, encompassing the need for large-scale, multi-center randomized controlled trials, in-depth microbial ecology studies, and the integration of multi-omics approaches with artificial intelligence. Regulatory and ethical challenges are critically addressed, underscoring the imperative for standardized protocols and rigorous long-term safety assessments. This comprehensive review seeks to guide future research endeavors and clinical applications of FMT-ICIs combination therapy, with the potential to improve cancer patient outcomes while ensuring both safety and efficacy. As this rapidly evolving field advances, maintaining a judicious balance between openness to innovation and cautious scrutiny is crucial for realizing the full potential of microbiome modulation in cancer immunotherapy.

The gut microbiota: an emerging modulator of drug resistance in hepatocellular carcinoma

Liver cancer is usually diagnosed at an advanced stage and is the third most common cause of cancer-related death worldwide. In addition to the lack of effective treatment options, resistance to therapeutic drugs is a major clinical challenge. The gut microbiota has recently been recognized as one of the key factors regulating host health. The microbiota and its metabolites can directly or indirectly regulate gene expression in the liver, leading to gut-liver axis dysregulation, which is closely related to liver cancer occurrence and the treatment response. Gut microbiota disturbance may participate in tumor progression and drug resistance through metabolite production, gene transfer, immune regulation, and other mechanisms. However, systematic reviews on the role of the gut microbiota in drug resistance in liver cancer are lacking. Herein, we review the relationships between the gut microbiota and the occurrence and drug resistance of hepatocellular carcinoma, summarize the emerging mechanisms underlying gut microbiota-mediated drug resistance, and propose new personalized treatment options to overcome this resistance.

Pushing the boundaries of radiotherapy-immunotherapy combinations: highlights from the 7th immunorad conference

Over the last decade, the annual Immunorad Conference, held under the joint auspicies of Gustave Roussy (Villejuif, France) and the Weill Cornell Medical College (New-York, USA) has aimed at exploring the latest advancements in the fields of tumor immunology and radiotherapy-immunotherapy combinations for the treatment of cancer. Gathering medical oncologists, radiation oncologists, physicians and researchers with esteemed expertise in these fields, the Immunorad Conference bridges the gap between preclinical outcomes and clinical opportunities. Thus, it paves a promising way toward optimizing radiotherapy-immunotherapy combinations and, from a broader perspective, improving therapeutic strategies for patients with cancer. Herein, we report on the topics developed by key-opinion leaders during the 7th Immunorad Conference held in Paris-Les Cordeliers (France) from September 27th to 29th 2023, and set the stage for the 8th edition of Immunorad which will be held at Weill Cornell Medical College (New-York, USA) in October 2024.

Pharmacomicrobiomics: a new field contributing to optimizing drug therapy in Parkinson's disease

Gut microbiota, which act as a determinant of pharmacokinetics, have long been overlooked. In recent years, a growing body of evidence indicates that the gut microbiota influence drug metabolism and efficacy. Conversely, drugs also exert a substantial influence on the function and composition of the gut microbiota. Pharmacomicrobiomics, an emerging field focusing on the interplay of drugs and gut microbiota, provides a potential foundation for making certain advances in personalized medicine. Understanding the communication between gut microbiota and antiparkinsonian drugs is critical for precise treatment of Parkinson's disease. Here, we provide a historical overview of the interplay between gut microbiota and antiparkinsonian drugs. Moreover, we discuss potential mechanistic insights into the complex associations between gut microbiota and drug metabolism. In addition, we also draw attention to microbiota-based biomarkers for predicting antiparkinsonian drug efficacy and examine current state-of-the-art knowledge of microbiota-based strategies to optimize drug therapy in Parkinson's disease.

Gut microbiota in hepatocellular carcinoma immunotherapy: immune microenvironment remodeling and gut microbiota modification

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related mortality, with limited treatment options at advanced stages. The gut microbiota, a diverse community of microorganisms residing in the gastrointestinal tract, plays a pivotal role in regulating immune responses through the gut-liver axis. Emerging evidence underscores its impact on HCC progression and the efficacy of immunotherapy. This review explores the intricate interactions between gut microbiota and the immune system in HCC, with a focus on key immune cells and pathways involved in tumor immunity. Additionally, it highlights strategies for modulating the gut microbiota - such as fecal microbiota transplantation, dietary interventions, and probiotics - as potential approaches to enhancing immunotherapy outcomes. A deeper understanding of these mechanisms could pave the way for novel therapeutic strategies aimed at improving patient prognosis.

Assessing live microbial therapeutic transmission

The development of fecal microbiota transplantation and defined live biotherapeutic products for the treatment of human disease has been an empirically driven process yielding a notable success of approved drugs for the treatment of recurrent Clostridioides difficile infection. Assessing the potential of this therapeutic modality in other indications with mixed clinical results would benefit from consistent quantitative frameworks to characterize drug potency and composition and to assess the impact of dose and composition on the frequency and duration of strain engraftment. Monitoring these drug properties and engraftment outcomes would help identify minimally sufficient sets of microbial strains to treat disease and provide insights into the intersection between microbial function and host physiology. Broad and correct usage of strain detection methods is essential to this advancement. This article describes strain detection approaches, where they are best applied, what data they require, and clinical trial designs that are best suited to their application.

Microbiota-centered interventions to boost immune checkpoint blockade therapies

Immune checkpoint blockade therapies have markedly advanced cancer treatment by invigorating antitumor immunity and extending patient survival. However, therapeutic resistance and immune-related toxicities remain major concerns. Emerging evidence indicates that microbial dysbiosis diminishes therapeutic response rates, while a diverse gut ecology and key beneficial taxa correlate with improved treatment outcomes. Therefore, there is a growing understanding that manipulating the gut microbiota could boost therapy efficacy. This review examines burgeoning methods that target the gut microbiome to optimize therapy and innovative diagnostic tools to detect dysbiosis, and highlights challenges that remain to be addressed in the field.

Gut microbiota in melanoma: Effects and pathogeneses

The gut microbiota exhibits intricate connections with the body's immune system and holds significant implications for various diseases and cancers. Currently, accumulating evidence suggests a correlation between the composition of the gut microbiota and the development, treatment, and prognosis of melanoma. However, the underlying pathogenesis remains incompletely elucidated. In this comprehensive review, we present an in-depth review of the role played by gut microbiota in melanoma tumorigenesis, growth, metastasis, treatment response, and prognosis. Furthermore, we discuss the potential utility of gut microbiota as a promising prognostic marker. Lastly, we summarize three routes through which gut microbiota influences melanoma: immunity, aging, and the endocrine system. By modulating innate and adaptive immunity in patients with melanoma across different age groups and genders, the gut microbiota plays a crucial role in anti-tumor immune regulation from tumorigenesis to prognosis management, thereby impacting tumor growth and metastasis. This review also addresses current study limitations while highlighting future research prospects.

Unraveling the potential of bioengineered microbiome-based strategies to enhance cancer immunotherapy

The human microbiome plays a pivotal role in the field of cancer immunotherapy. The microbial communities that inhabit the gastrointestinal tract, as well as the bacterial populations within tumors, have been identified as key modulators of therapeutic outcomes, affecting immune responses and reprogramming the tumor microenvironment. Advances in synthetic biology have made it possible to reprogram and engineer these microorganisms to improve antitumor activity, enhance T-cell function, and enable targeted delivery of therapies to neoplasms. This review discusses the role of the microbiome in modulating both innate and adaptive immune mechanisms-ranging from the initiation of cytokine production and antigen presentation to the regulation of immune checkpoints-and discusses how these mechanisms improve the efficacy of immune checkpoint inhibitors. We highlight significant advances with bioengineered strains like Escherichia coli Nissle 1917, Lactococcus lactis, Bifidobacterium, and Bacteroides, which have shown promising antitumor efficacy in preclinical models. These engineered microorganisms not only efficiently colonize tumor tissues but also help overcome resistance to standard therapies by reprogramming the local immune environment. Nevertheless, several challenges remain, such as the requirement for genetic stability, effective tumor colonization, and the control of potential safety issues. In the future, the ongoing development of genetic engineering tools and the optimization of bacterial delivery systems are crucial for the translation of microbiome-based therapies into the clinic. This review highlights the potential of bioengineered microbiota as an innovative, personalized approach in cancer immunotherapy, bringing hope for more effective and personalized treatment options for patients with advanced malignancies.

Harnessing the human microbiome and its impact on immuno-oncology and nanotechnology for next-generation cancer therapies

The integration of microbiome research and nanotechnology represents a significant advancement in immuno-oncology, potentially improving the effectiveness of cancer immunotherapies. Recent studies highlight the influential role of the human microbiome in modulating immune responses, presenting new opportunities to enhance immune checkpoint inhibitors (ICIs) and other cancer therapies. Nanotechnology offers precise drug delivery and immune modulation capabilities, minimizing off-target effects while maximizing therapeutic outcomes. This review consolidates current knowledge on the interactions between the microbiome and the immune system, emphasizing the microbiome's impact on ICIs, and explores the incorporation of nanotechnology in cancer treatment strategies. Additionally, it provides a forward-looking perspective on the synergistic potential of microbiome modulation and nanotechnology to overcome existing challenges in immuno-oncology. This integrated approach may enhance the personalization and effectiveness of next-generation cancer treatments, paving the way for transformative patient care.

Impact of Antibiotics and Chronic Medications on Efficacy of Immune Checkpoint Inhibitors in Patients With Hepatocellular Carcinoma

BACKGROUND AND AIMS

The interaction of immune checkpoint inhibitors (ICI) and concomitant medications such as antibiotics, metformin, statins, beta-blockers, proton pump inhibitors (PPIs), nonsteroidal anti-inflammatory drugs (NSAIDs), and low-dose aspirin has been studied in other malignancies. Our study aims to investigate the relationship between these medications and ICI efficacy in patients with advanced hepatocellular carcinoma (aHCC).

METHODS

A retrospective review of patients who received at least one dose of ICIs between May 2015 and November 2019 was performed. The primary objectives were to compare the overall survival (OS) and progression-free survival (PFS) between patients with and without medication usage. Log rank test was used to assess for differences in survival. Hazard ratios were reported using Cox proportional hazard regression analysis. The data cutoff date was December 31, 2020.

RESULTS

A total of 168 patients were included. Median age was 69 years, 85.7% male, 60.7% ECOG 0, 78.0% Child-Pugh A liver cirrhosis, 57.7% hepatitis B etiology, 8.9% hepatitis C, and 33.3% nonviral. One hundred three patients (61.3%) received ICI monotherapy, while 38.7% received ICI in combination. Sixty-two patients (36.9%) had concomitant antibiotic usage, 26.8% metformin, 30.4% statin, 31.0% beta-blockers, 60.1% PPI, 6.5% NSAIDs, and 11.9% aspirin. Patients with aHCC receiving antibiotics did not have a shorter OS (adjusted HR [aHR] 1.40, 95% CI 0.94-2.09, p = 0.096) or shorter PFS (aHR 0.94, 95% CI 0.66-1.34, p = 0.73), as compared to those who did not receive antibiotics. However, patients with aHCC of viral hepatitis etiology receiving ICI treatment and concurrent antibiotics had shorter OS (5.5 vs. 14.2 months, aHR 1.93, 95% CI 1.17-3.17, p = 0.010) and PFS (1.1 vs. 2.6 months, aHR 2.69, 95% CI 1.28-5.65, p = 0.009), as compared to those who did not receive antibiotics.

CONCLUSIONS

The use of antibiotics may diminish ICI efficacy in patients with aHCC of viral hepatitis etiology, while the use of metformin, statins, beta-blockers, NSAIDs, and aspirin is not associated with significant clinical outcomes.

Gut Microbiota in Immuno-Oncology: A Practical Guide for Medical Oncologists With a Focus on Antibiotics Stewardship

The gut microbiota has emerged as a critical determinant of immune checkpoint inhibitor (ICI) efficacy, resistance, and toxicity. Retrospective and prospective studies profiling the taxonomic composition of intestinal microbes of patients treated with ICI have revealed specific gut microbial signatures associated with response. By contrast, dysbiosis, which can be caused by chronic inflammatory processes (such as cancer) or comedications, is a risk factor of resistance to ICI. Recent large-scale meta-analyses have confirmed that antibiotic (ATB) use before or during ICI therapy alters the microbiota repertoire and significantly shortens overall survival, even after adjusting for prognostic factors. These results underscore the importance of implementing ATB stewardship recommendations in routine oncology practice. Microbiota-centered interventions are now being explored to treat gut dysbiosis and optimize ICI responses. Early-phase clinical trials evaluating fecal microbiota transplantation (FMT) from ICI responders or healthy donors have shown that this approach is safe and provided preliminary data on potential efficacy to overcome both primary and secondary resistance to ICI in melanoma, non-small cell lung cancer, and renal cell carcinoma. More targeted interventions including live bacterial products including Clostridium butyricum and Akkermansia massiliensis represent novel microbiome-based adjunct therapies. Likewise, dietary interventions, such as high-fiber diets, have shown promise in enhancing ICI activity. In this ASCO Educational Book, we summarize the current state-of-the-evidence of the clinical relevance of the intestinal microbiota in cancer immunotherapy and provide a practical guide for ATB stewardship.

Intestinal Microbiome Modulation of Therapeutic Efficacy of Cancer Immunotherapy

Bacteria are associated with certain cancers and may induce genetic instability and cancer progression. The gut microbiome modulates the response to cancer therapy. Training machine learning models with response associated taxa or bacterial genes predict patients' response to immunotherapies with moderate accuracy. Clinical trials targeting the gut microbiome to improve immunotherapy efficacy have been conducted. While single bacterial strains or small consortia have not be reported yet to be successful, encouraging results have been reported in small single arm and randomized studies using transplant of fecal microbiome from cancer patients who successfully responded to therapy or from healthy volunteers.

Gut microbiome and colorectal cancer: From pathogenesis to treatment

Colorectal cancer (CRC) continues to rank among the most prevalent cancers worldwide. A growing body of research indicates that the microbiome significantly influences the onset, development, and progression of CRC, in addition to affecting the efficacy of various systemic therapies. The composition of the microbiome, shaped by factors such as bacterial strains, geography, ethnicity, gender, and dietary habits, provides essential information for CRC screening, early diagnosis, and the prediction of treatment responses. Modulating the microbiome presents a highly promising medical strategy for improving individual health. This review aims to present a thorough overview of recent research concerning the interplay between host microbiota and CRC, along with its implications for screening and the immune response against tumors in the context of cancer treatment.

Immune checkpoint inhibitor (ICI) therapy in central nervous system cancers: State-of-the-art and future outlook

Invasive central nervous system (CNS) cancers are an area where the development of breakthrough therapies is urgently needed. For instance, conditions such as glioblastoma multiforme (GBM) are associated with poor clinical prognosis, with the majority of trials offering no improvement to marginally enhanced survival. Unleashing the potential of targeting the immune system in CNS cancers has gained attention in recent years. Inhibition of immune checkpoints such as CTLA-4, PD-1/PD-L1, TIM-3, and LAG-3 has been attempted in recent trials. While potentially offering a notable edge over other immunotherapies, multi-organ adverse events have been found with the administration of immune checkpoint inhibitors (ICIs). The present review captures the state-of-the-art evidence on ICI treatments in different CNS cancers. Also, we discuss the value of combinational therapies involving ICIs as well as next-generation therapeutics such as bispecific antibodies targeting PD-1/LAG-3/TIM-3 and CRISPR-Cas9-edited PD-1-knock-out checkpoint-resistant CAR T-cells.

Intestinal dysbiosis and colorectal cancer

ABSTRACT

Colorectal cancer (CRC) is one of the leading causes of cancer-related morbidity and mortality worldwide, highlighting the urgent need for novel preventive and therapeutic strategies. Emerging research highlights the crucial role of the gut microbiota, including bacteria, fungi, viruses, and their metabolites, in the pathogenesis of CRC. Dysbiosis, characterized by an imbalance in microbial composition, contributes to tumorigenesis through immune modulation, metabolic reprogramming, and genotoxicity. Specific bacterial species, such as Fusobacterium nucleatum and enterotoxigenic Bacteroides fragilis, along with fungal agents like Candida species, have been implicated in CRC progression. Moreover, viral factors, including Epstein-Barr virus and human cytomegalovirus, are increasingly recognized for their roles in promoting inflammation and immune evasion. This review synthesizes the latest evidence on host-microbiome interactions in CRC, emphasizing microbial metabolites, such as short-chain fatty acids and bile acids, which may act as both risk factors and therapeutic agents. We further discuss the latest advances in microbiota-targeted clinical applications, including biomarker-assisted diagnosis, next-generation probiotics, and microbiome-based interventions. A deeper understanding of the role of gut microbiome in CRC pathogenesis could pave the way for diagnostic, preventive, and personalized therapeutic strategies.

Microbiota mechanisms in cancer progression and therapy

The composition of the microbiota in patients has been shown to correlate with cancer progression and response to therapy, highlighting unique opportunities to improve patient outcomes. In this review, we discuss the challenges and advancements in understanding the chemical mechanisms of specific microbiota species, pathways, and molecules involved in cancer progression and treatment. We also describe the modulation of cancer and immunotherapy by the microbiota, along with approaches for investigating microbiota enzymes and metabolites. Elucidating these specific microbiota mechanisms and molecules should offer new opportunities for developing enhanced diagnostics and therapeutics to improve outcomes for cancer patients. Nonetheless, many microbiota mechanisms remain to be determined and require innovative chemical genetic approaches.

Associations between ionomic profile and metabolic abnormalities in a murine model of sodium sulfide induced alopecia areata

Background

Alopecia areata (AA) is a common autoimmune disorder marked by non-scarring hair loss, which imposes significant psychosocial stress on patients. To investigate key metabolites and ions involved in AA's pathogenesis, we utilized gas chromatography-mass spectrometry (GC-MS) for non-targeted metabolomics and inductively coupled plasma mass spectrometry (ICP-MS) for ionomics.

Methods

A total of 36 six-week-old Kunming mice were divided into control (n = 12), an AA model (n = 12), and tofacitinib-treated groups (n = 12). A mouse model of AA was established by sodium sulfide (Na2S) induction in both the model and treatment groups, while the treatment group (n = 12) received tofacitinib treatment at a dose of 1 mg/kg. GC-MS was used to determine the metabolic profiling in serum samples, and ICP-MS was applied to assess ionomic changes in the serum samples. Potential metabolites and ions were identified using orthogonal partial least squares-discriminant analysis (OPLS-DA). Subsequently, MetaboAnalyst 5.0 and the Kyoto Encyclopedia of Genes and Genomes database (KEGG) were used to map the metabolic pathways. Spearman correlation analysis was conducted to identify relationships and potential regulatory interactions between differential metabolites and individual ions.

Results

Metabolomics analysis revealed that D-lactic acid, glycolic acid, linoleic acid, petroselinic acid, and stearic acid are key differential metabolites between the control, AA model, and tofacitinib groups. Pathway analysis highlighted that the biosynthesis of unsaturated fatty acids and linoleic acid metabolism are pivotal pathways implicated in the onset and progression of AA. Furthermore, ionomics analysis identified magnesium, aluminum, titanium, and nickel as differential ions among the three groups. The integrated metabolomics and ionomics analysis indicated that linoleic acid, a key differential metabolite according to the KEGG database, shows a positive correlation with phosphorus, vanadium, magnesium, and zinc. Among these, Mg2+ (Mg2+) play a crucial role in modulating CD8+ T cell infiltration, thereby influencing the disease progression in AA.

Conclusion

Tofacitinib inhibits CD8+ T cell infiltration in hair follicles affected by sodium sulfide-induced AA by modulating the linoleic acid metabolism-Mg2+ pathway. Our findings offer new insights and potential avenues for the clinical diagnosis and treatment of AA, suggesting that targeting metabolic and ionic pathways could enhance therapeutic outcomes.

Roles of the gut microbiota in immune-related adverse events: mechanisms and therapeutic intervention

Immune checkpoint inhibitors (ICIs) constitute a major breakthrough in the field of cancer therapy; their use has resulted in improved outcomes across various tumour types. However, ICIs can cause a diverse range of immune-related adverse events (irAEs) that present a considerable challenge to the efficacy and safety of these treatments. The gut microbiota has been demonstrated to have a crucial role in modulating the tumour immune microenvironment and thus influences the effectiveness of ICIs. Accumulating evidence indicates that alterations in the composition and function of the gut microbiota are also associated with an increased risk of irAEs, particularly ICI-induced colitis. Indeed, these changes in the gut microbiota can contribute to the pathogenesis of irAEs. In this Review, we first summarize the current clinical challenges posed by irAEs. We then focus on reported correlations between alterations in the gut microbiota and irAEs, especially ICI-induced colitis, and postulate mechanisms by which these microbial changes influence the occurrence of irAEs. Finally, we highlight the potential value of gut microbial changes as biomarkers for predicting irAEs and discuss gut microbial interventions that might serve as new strategies for the management of irAEs, including faecal microbiota transplantation, probiotic, prebiotic and/or postbiotic supplements, and dietary modulations.

The Microbiome and Cancer: A Translational Science Review

Importance

Growing evidence suggests that microbes located within the gastrointestinal tract and other anatomical locations influence the development and progression of diseases such as cancer.

Observations

Clinical and preclinical evidence suggests that microbes in the gastrointestinal tract and other anatomical locations, such as the respiratory tract, may affect carcinogenesis, development of metastases, cancer treatment response, and cancer treatment-related adverse effects. Within tumors of patients with cancer, microbes may affect response to treatment, and therapies that reduce or eliminate these microbes may improve outcomes in patients with cancer. Modulating gastrointestinal tract (gut) microbes through fecal microbiota transplant and other strategies such as dietary intervention (eg, high-fiber diet intervention) has improved outcomes in small studies of patients treated with cancer immunotherapy. In contrast, disruption of the gut microbiota by receipt of broad-spectrum antibiotics prior to treatment with cancer immunotherapy has been associated with poorer overall survival and higher rates of adverse effects in patients treated with immune checkpoint blockade for solid tumors and also with chimeric antigen receptor T-cell therapy for hematologic malignancies.

Conclusions and Relevance

Microbes in the gut and other locations in the body may influence the development and progression of cancer and may affect the response to adverse effects from cancer therapy. Future therapies targeting microbes in the gut and other locations in the body could potentially improve outcomes in patients with cancer.

The Effect of Microbiome-Derived Metabolites in Inflammation-Related Cancer Prevention and Treatment

Chronic inflammation plays a crucial role in cancer development, yet the mechanisms linking the microbiome to inflammation-related carcinogenesis remain unclear. Emerging evidence suggests that microbiome-derived metabolites influence inflammatory pathways, presenting both challenges and opportunities for therapy. However, a deeper understanding of how these metabolites regulate inflammation and contribute to cancer prevention is still needed. This review explores recent advances in microbiome-derived metabolites and their roles in inflammation-related carcinogenesis. It highlights key molecular mechanisms, emerging therapies, and unresolved challenges. Synthesizing current research, including clinical trials and experimental models, bridges the gap between microbiome science and cancer therapy. Microbial metabolites such as short-chain fatty acids (SCFAs), polyamines, indoles, and bile acids play vital roles in regulating inflammation and suppressing cancer. Many metabolites exhibit potent anti-inflammatory and immunomodulatory effects, demonstrating therapeutic potential. Case studies show promising results, but challenges such as metabolite stability, bioavailability, and individual variability remain. Understanding microbiome-metabolite interactions offers novel strategies for cancer prevention and treatment. This review identifies knowledge gaps and proposes future research directions to harness microbiome-derived metabolites for innovative cancer therapies. Addressing these issues may pave the way for microbiome-targeted cancer interventions.

Cutaneous T cell immunity

The skin is the primary barrier against environmental insults, safeguarding the body from mechanical, chemical and pathogenic threats. The frequent exposure of the skin to environmental challenges requires an immune response that incorporates a sophisticated combination of defenses. Tissue-resident lymphocytes are pivotal for skin immunity, working in tandem with commensal bacteria to maintain immune surveillance and homeostasis, as well as participating in the pathogenesis of several skin diseases. Indeed, it has been estimated that the human skin harbors nearly twice as many T cells as found in the circulation. Effective treatment of skin diseases and new therapy development require a thorough understanding of the complex interactions among skin tissue, immune cells and the microbiota, which together regulate the skin's immune balance. This Review explores the latest developments and understanding of this critical barrier organ, with a specific focus on the role of skin-resident T cells.

Deficient Mismatch Repair and Microsatellite Instability in Solid Tumors

The integrity of the genome is maintained by mismatch repair (MMR) proteins that recognize and repair base mismatches and insertion/deletion errors generated during DNA replication and recombination. A defective MMR system results in genome-wide instability and the progressive accumulation of mutations. Tumors exhibiting deficient MMR (dMMR) and/or high levels of microsatellite instability (termed "microsatellite instability high", or MSI-H) have been shown to possess fundamental differences in clinical, pathological, and molecular characteristics, distinguishing them from their "microsatellite stable" (MSS) counterparts. Molecularly, they are defined by a high mutational burden, genetic instability, and a distinctive immune profile. Their distinct genetic and immunological profiles have made dMMR/MSI-H tumors particularly amenable to treatment with immune checkpoint inhibitors (ICIs). The ongoing development of biomarker-driven therapies and the evaluation of novel combinations of immune-based therapies, with or without the use of conventional cytotoxic treatment regimens, continue to refine treatment strategies with the goals of maximizing therapeutic efficacy and survival outcomes in this distinct patient population. Moreover, the resultant knowledge of the mechanisms by which these features are suspected to render these tumors more responsive, overall, to immunotherapy may provide information regarding the potential optimization of this therapeutic approach in tumors with proficient MMR (pMMR)/MSS tumors.

New insights into gut microbiota-prostate cancer crosstalk

Recent evidence underscores a reciprocal relationship between the gut microbiota and prostate cancer (PCa). Dysbiosis, often driven by Western dietary habits and antibiotic use, can heighten systemic inflammation and hinder antitumor immunity, thereby fostering PCa onset and progression. Conversely, certain gut microbes and their metabolites may protect against tumor growth by modulating immune and hormonal pathways that impact therapeutic responses, including androgen deprivation therapy (ADT). Emerging evidence links gut microbial shifts to PCa aggressiveness, potentially sustaining local androgen production and promoting resistance. In this review, we explore current understanding of the gut-PCa interplay, highlighting key knowledge gaps and the need for further research to clarify how targeting the microbiome might influence PCa outcomes.

Single-cell transcriptomic analysis reveals gut microbiota-immunotherapy synergy through modulating tumor microenvironment

The gut microbiota crucially regulates the efficacy of immune checkpoint inhibitor (ICI) based immunotherapy, but the underlying mechanisms remain unclear at the single-cell resolution. Using single-cell RNA sequencing and subsequent validations, we investigate gut microbiota-ICI synergy by profiling the tumor microenvironment (TME) and elucidating critical cellular interactions in mouse models. Our findings reveal that intact gut microbiota combined with ICIs may synergistically increase the proportions of CD8+, CD4+, and γδ T cells, reduce glycolysis metabolism, and reverse exhausted CD8+ T cells into memory/effector CD8+ T cells, enhancing antitumor response. This synergistic effect also induces macrophage reprogramming from M2 protumor Spp1+ tumor-associated macrophages (TAMs) to Cd74+ TAMs, which act as antigen-presenting cells (APCs). These macrophage subtypes show a negative correlation within tumors, particularly during fecal microbiota transplantation. Depleting Spp1+ TAMs in Spp1 conditional knockout mice boosts ICI efficacy and T cell infiltration, regardless of gut microbiota status, suggesting a potential upstream role of the gut microbiota and highlighting the crucial negative impact of Spp1+ TAMs during macrophage reprogramming on immunotherapy outcomes. Mechanistically, we propose a γδ T cell-APC-CD8+ T cell axis, where gut microbiota and ICIs enhance Cd40lg expression on γδ T cells, activating Cd40 overexpressing APCs (e.g., Cd74+ TAMs) through CD40-CD40L-related NF-κB signaling and boosting CD8+ T cell responses via CD86-CD28 interactions. These findings highlight the potential importance of γδ T cells and SPP1-related macrophage reprogramming in activating CD8+ T cells, as well as the synergistic effect of gut microbiota and ICIs in immunotherapy through modulating the TME.

Using mathematical modelling and AI to improve delivery and efficacy of therapies in cancer

Mathematical modelling has proven to be a valuable tool in predicting the delivery and efficacy of molecular, antibody-based, nano and cellular therapy in solid tumours. Mathematical models based on our understanding of the biological processes at subcellular, cellular and tissue level are known as mechanistic models that, in turn, are divided into continuous and discrete models. Continuous models are further divided into lumped parameter models - for describing the temporal distribution of medicine in tumours and normal organs - and distributed parameter models - for studying the spatiotemporal distribution of therapy in tumours. Discrete models capture interactions at the cellular and subcellular levels. Collectively, these models are useful for optimizing the delivery and efficacy of molecular, nanoscale and cellular therapy in tumours by incorporating the biological characteristics of tumours, the physicochemical properties of drugs, the interactions among drugs, cancer cells and various components of the tumour microenvironment, and for enabling patient-specific predictions when combined with medical imaging. Artificial intelligence-based methods, such as machine learning, have ushered in a new era in oncology. These data-driven approaches complement mechanistic models and have immense potential for improving cancer detection, treatment and drug discovery. Here we review these diverse approaches and suggest ways to combine mechanistic and artificial intelligence-based models to further improve patient treatment outcomes.

Gut microbiota in cancer initiation, development and therapy

Cancer has long been associated with genetic and environmental factors, but recent studies reveal the important role of gut microbiota in its initiation and progression. Around 13% of cancers are linked to infectious agents, highlighting the need to identify the specific microorganisms involved. Gut microbiota can either promote or inhibit cancer growth by influencing oncogenic signaling pathways and altering immune responses. Dysbiosis can lead to cancer, while certain probiotics and their metabolites may help reestablish micro-ecological balance and improve anti-tumor immune responses. Research into targeted approaches that enhance therapy with probiotics is promising. However, the effects of probiotics in humans are complex and not yet fully understood. Additionally, methods to counteract harmful bacteria are still in development. Early clinical trials also indicate that modifying gut microbiota may help manage side effects of cancer treatments. Ongoing research is crucial to understand better how gut microbiota can be used to improve cancer prevention and treatment outcomes.

Gut microbiome associated with PARP inhibitor efficacy in patients with ovarian cancer

OBJECTIVE

To investigate an association between the gut microbiome and efficacy of poly(ADP-ribose) polymerase inhibitors (PARPi) in ovarian cancer.

METHODS

This study conducted fecal microbiome analysis (16S rRNA gene sequencing) and circulating tumor DNA (ctDNA) profiling for ovarian cancer patients who underwent PARPi maintenance therapy. Fecal and blood samples were collected at the baseline and the progressive disease (PD) or last follow-up. The relative abundance of gut microbes and progression-free survival (PFS) were analyzed using linear discriminant analysis of effect size and the Cox proportional hazard model according to BRCA1/2 mutation (BRCA1/2mut) status detected by ctDNA sequencing.

RESULTS

Baseline samples were available from 23 BRCA1/2mut-positive patients and 33 BRCA1/2mut-negative patients. The microbes enriched in the baseline samples with long PFS were Bifidobacterium, Roseburia, Dialister, Butyricicoccus, and Bilophila for BRCA1/2mut-positive patients and Phascolarctobacterium for BRCA1/2mut-negative patients. In multivariate analyses dividing patients by the median values of relative abundances, no bacteria were associated with PFS in BRCA1/2mut-positive patients, whereas high Phascolarctobacterium abundances (≥1.11%) was significantly associated with longer PFS in BRCA1/2mut-negative patients (median 14.0 vs. 5.9 months, hazard ratio=0.28; 95% confidence interval=0.11-0.69; p=0.014). In the last samples, the relative abundances of Phascolarctobacterium were significantly higher in patients without PD (n=5) than those with PD (n=15) (median 1.25% vs. 0.06%; p=0.016).

CONCLUSION

High fecal composition of Phascolarctobacterium was associated with prolonged PFS in patients with BRCA1/2mut-negative ovarian cancer receiving PARPi therapy. Our results would provide new insights for future research.

The gut microbiome and cancer: from tumorigenesis to therapy

The gut microbiome has a crucial role in cancer development and therapy through its interactions with the immune system and tumour microenvironment. Although evidence links gut microbiota composition to cancer progression, its precise role in modulating treatment responses remains unclear. In this Review, we summarize current knowledge on the gut microbiome's involvement in cancer, covering its role in tumour initiation and progression, interactions with chemotherapy, radiotherapy and targeted therapies, and its influence on cancer immunotherapy. We discuss the impact of microbial metabolites on immune responses, the relationship between specific bacterial species and treatment outcomes, and potential microbiota-based therapeutic strategies, including dietary interventions, probiotics and faecal microbiota transplantation. Understanding these complex microbiota-immune interactions is critical for optimizing cancer therapies. Future research should focus on defining microbial signatures associated with treatment success and developing targeted microbiome modulation strategies to enhance patient outcomes.

EHF promotes liver cancer progression by meditating IL-6 secretion through transcription regulation of KDM2B in TAMs

BACKGROUND

Macrophages are key immune cell types in liver, which are thought to be involved in tumor development. Recent studies indicated that TAMs exhibit M2 phenotypes. However, the mechanism of macrophages related to tumor progression in liver cancer is largely unknown. We aim to investigate the mechanism of EHF in TAMs associated with liver cancer progression.

METHODS

The differently expressed genes of M0, M1, and M2 macrophages were analyzed by RNA sequencing. Cytokine array was used to detect the differently expressed cytokines in M2 macrophages. We performed CUT-Tag analysis for the identification of promoter regions that interacting with EHF protein. ChIP and luciferase analysis were used to verify the interaction between EHF and KDM2B.

RESULTS

EHF was overexpressed in M2 macrophages. Knockdown of EHF in M2 macrophages could inhibit migration and invasion of MHCC97-L cells co-cultured with M2 macrophages in vitro and in vivo. The level of IL-6 was decreased in M2 macrophages with lower expression of EHF. EHF could bind the promoter region of KDM2B. The transcription level of KDM2B was down-regulated by knockdown of EHF in M2 macrophages. The results of this study indicated that EHF could promote liver cancer cell metastasis by IL-6 through regulating the transcription level of KDM2B in M2 macrophages.

CONCLUSION

Our study revealed a novel aspect of macrophages in liver cancer and showed EHF could be a promising therapeutic target of liver cancer.

Combination therapy with immune checkpoint inhibitors in colorectal cancer: Challenges, resistance mechanisms, and the role of microbiota

Colorectal cancer (CRC) is still one of the leading causes of cancer deaths worldwide. Even though there has been progress in cancer immunotherapy, the results of applying immune checkpoint inhibitors (ICIs) have been unsatisfactory, especially in microsatellite stable (MSS) CRC. Single-agent ICIs that target programmed cell death-1 (PD-1)/ PD-L1, cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), T cell Ig- and mucin-domain-containing molecule-3 (TIM-3), and lymphocyte activation gene (LAG)-3 have emerged as having specific benefits. However, many primary and secondary resistance mechanisms are available in the tumor microenvironment (TME) that prevent it from happening. Combination strategies, such as the use of anti-PD-1 and anti-CTLA-4, can be effective in overcoming these resistance pathways, but toxicities remain a significant concern. Moreover, ICIs have been integrated with various treatment modalities, including chemotherapy, radiotherapy, antibiotics, virotherapy, polyadenosine diphosphate-ribose polymerase (PARP) inhibitors, and heat shock protein 90 (HSP90) inhibitors. The outcomes observed in both preclinical and clinical settings have been encouraging. Interestingly, manipulating gut microbiota via fecal microbiota transplantation (FMT) has been identified as a new strategy to increase the efficacy of immunotherapy in CRC patients. Therefore, integrating ICIs with other treatment approaches holds promise in enhancing the prognosis of CRC patients. This review focuses on the unmet need for new biomarkers to select patients for combination therapies and the ongoing work to overcome resistance and immune checkpoint blockade.

Gut reactions: harnessing microbial metabolism to fuel next-generation cancer immunotherapy

Immunotherapies, including immune checkpoint inhibitors and chimeric antigen receptor-T cell therapies, depend heavily on a healthy and diverse gut microbiome for optimal efficacy. Dysbiosis, or an imbalance in gut microbial composition and function, can diminish immunotherapy responses by altering immune cell trafficking and metabolic output. Key microbial metabolites such as short-chain fatty acids and modified bile acids shape host immunity and influence T-cell function, while their disruption can foster an immunosuppressive microenvironment. Emerging strategies to restore a balanced microbiome and boost treatment outcomes include dietary interventions, supplementation with beneficial microbes, and fecal microbiota transplantation. Despite these advances, challenges remain in defining dysbiosis, identifying reliable biomarkers, and tailoring microbiota-centered interventions. Nevertheless, as our understanding evolves, the gut microbiome holds promise as an integral component of personalized cancer immunotherapy.

Expanding horizons of cancer immunotherapy: hopes and hurdles

Background

Tumor displays various forms of tumor heterogeneity including immune heterogeneity that allow cancer cells to survive during conventional anticancer drug interventions. Thus, there is a strong rationale for overcoming anticancer drug resistance by employing the components of immune cells. Using the immune system to target tumor cells has revolutionized treatment. Recently, significant progress has been achieved at preclinical and clinical levels to benefit cancer patients.

Approach

A review of literature from the past ten years across PubMed, Scopus, and Web of Science focused on immunotherapy strategies. These include immune checkpoint inhibitors (ICIs), tumor-infiltrating lymphocyte therapy, antibody-drug conjugates (ADCs), cancer vaccines, CAR T-cell therapy, and the role of the gut microbiome.

Conclusion

While immunotherapy outcomes have improved, particularly for tumor types such as melanoma and non-small cell lung cancer (NSCLC), challenges persist regarding predictive biomarker identification and better management. Ongoing research on modifiers of immune function like gut microbiome-derived metabolites, next-generation ADCs, and new classes of biologics is warranted. Overall, continued investigation toward optimizing synergistic immunotherapeutic combinations through strategic drug delivery systems is imperative for preclinical and clinical success in cancer patients.

Combinational therapeutic strategies to overcome resistance to immune checkpoint inhibitors

Over the past few years, immune checkpoint inhibitors resulted in magnificent and durable successes in treating cancer; however, only a minority of patients respond favorably to the treatment due to a broad-spectrum of tumor-intrinsic and tumor-extrinsic factors. With the recent insights gained into the mechanisms of resistance, combination treatment strategies to overcome the resistance and enhance the therapeutic potential of immune checkpoint inhibitors are emerging and showing promising results in both pre-clinical and clinical settings. This has been derived through multiple interconnected mechanisms such as enhancing tumor immunogenicity, improving neoantigen processing and presentation in addition to augmenting T cell infiltration and cytotoxic potentials. In the clinical settings, several avenues of combination treatments involving immune checkpoint inhibitors were associated with considerable improvement in the therapeutic outcome in terms of patient's survival and tumor growth control. This, in turn, increased the spectrum of cancer patients benefiting from the unprecedented and durable effects of immune checkpoint inhibitors leading to their adoption as a first-line treatment for certain cancers. Moreover, the significance of precision medicine in cancer immunotherapy and the unmet demand to develop more personalized predictive biomarkers and treatment strategies are also highlighted in this review.

Acquired resistance to immunotherapy in solid tumors

Acquired resistance to immunotherapy (ARI) is a major challenge in solid tumors, limiting long-term success in up to 65% of patients who initially respond to immunotherapy. Defining ARI clinically remains complex, but ongoing efforts aim to establish standardized criteria. This review describes recent insights into ARI, revealing complex mechanisms involving both tumor-intrinsic mechanisms - such as antigen loss and presentation defects, interferon γ (IFNγ) insensitivity, tumor-mediated T cell exclusion, and metabolic reprogramming - as well as extrinsic factors such as inhibitory molecule upregulation, immunosuppressive cells, extracellular matrix (ECM) remodeling, and dysbiotic microbiota. Understanding the development of ARI is crucial for prevention and effective interventions. The integration of innovative strategies and translational research on appropriately collected samples is key to overcoming ARI and ensuring durable benefits for patients.

Advancing Cancer Treatment: A Review of Immune Checkpoint Inhibitors and Combination Strategies

A groundbreaking milestone in oncology has been the recognition and targeted elimination of malignant cells through cancer immunotherapy, which harnesses the body's immune system to attack cancer [...].

The effects of repeated fecal transplantation and activated charcoal treatment on gut dysbiosis induced by concurrent ceftriaxone administration in mice

BACKGROUND

Antibiotic treatment contributes to gut microbiota dysbiosis. Previous studies have shown that fecal microbiota transplantation (FMT), fecal filtrate (FF), and activated charcoal (AC) treatments can prevent gut microbiota disturbances caused by antibiotics or Clostridioides difficile infection. However, these treatments have typically been limited to restoring gut microbiota after dysbiosis, and antibiotics must be discontinued beforehand. Here, we investigated the protective effects of these treatments on gut microbiota to prevent dysbiosis during concurrent systemic ceftriaxone administration.

METHODS

C57BL/6 mice that received intraperitoneal ceftriaxone for seven consecutive days were concomitantly treated with AC, FMT, FMT + AC, FF, or FF + AC via oral gavage. Gut microbiomes were analyzed using 16 S rRNA gene sequencing, and intestinal mucosal pathology was evaluated through H&E staining.

RESULTS

Systemic ceftriaxone administration significantly altered gut microbiota diversity and composition but did not affect intestinal mucosal histology. Alpha and beta diversity analyses showed that microbiota diversity decreased in all ceftriaxone-treated groups, with the ceftriaxone + FF + AC group retaining the highest diversity. The ceftriaxone + AC group had higher Enterococcus but lower Muribaculaceae relative abundances than the control (no ceftriaxone), ceftriaxone only, and ceftriaxone + FF + AC groups.

CONCLUSIONS

These results show that fecal filtrate transplantation combined with activated charcoal treatment may help balance gut microbiota diversity and reduce the presence of resistant bacteria during ceftriaxone exposure.

Optimizing anti-PD-1/PD-L1 therapy efficacy and fecal microbiota transplantation donor selection through gut mycobiome-based enterotype

Immunotherapy has revolutionized cancer treatment, but response variability remains a challenge. The gut microbiome's role in therapeutic efficacy is well established, but the impact of the gut mycobiome is less understood. Using unsupervised clustering, we identify two gut mycobiome-based enterotypes, favorable type and unfavorable type, characterized by distinct microbial compositions linked to immunotherapy outcomes. Favorable-type enterotypes exhibit higher fungal and bacterial alpha diversity, enriched butyrate-producing bacteria, and metabolic pathways related to butyric acid and sugar/starch metabolism. External validation confirms their predictive value in assessing immunotherapy efficacy. Multi-omics analysis reveals increased CD8+ T cell infiltration in the tumor microenvironment of favorable-type patients. Fecal microbiota transplantation (FMT) from favorable-type donors enhances anti-PD-1 sensitivity, promotes CD8+ T cell infiltration, and boosts butyrate production in vivo. These findings highlight the gut mycobiome's role in immunotherapy response and support FMT from favorable-type donors as a potential strategy for improving treatment outcomes and patient stratification.

The gut microbiota promotes pain in fibromyalgia

Fibromyalgia is a prevalent syndrome characterized by widespread pain in the absence of evident tissue injury or pathology, making it one of the most mysterious chronic pain conditions. The composition of the gut microbiota in individuals with fibromyalgia differs from that of healthy controls, but its functional role in the syndrome is unknown. Here, we show that fecal microbiota transplantation from fibromyalgia patients, but not from healthy controls, into germ-free mice induces pain and numerous molecular phenotypes that parallel known changes in fibromyalgia patients, including immune activation and metabolomic profile alterations. Replacing the fibromyalgia microbiota with a healthy microbiota substantially alleviated pain in mice. An open-label trial in women with fibromyalgia (Registry MOH_2021-11-04_010374) showed that transplantation of a healthy microbiota is associated with reduced pain and improved quality of life. We conclude that altered gut microbiota has a role in fibromyalgia pain, highlighting it as a promising target for therapeutic interventions.

Statin therapy associated Lactobacillus intestinalis attenuates pancreatic fibrosis through remodeling intestinal homeostasis

Chronic pancreatitis (CP) is characterized by irreversible fibrotic destruction and impaired pancreatic function. CP disrupts lipid metabolism and causes the imbalance of gut microbiota which in turn exacerbates pancreatic fibrosis. Statins alter gut microbiota and exert anti-inflammatory effects, but its role in CP has not been fully elucidated. Here, we found that statins-associated higher abundance of Lactobacillus intestinalis (L.intestinalis) maintained gut homeostasis that restrained bacteria translocation from gut to the pancreas, which eventually aggravated pancreatic fibrosis through inhibiting CD8+T cells-dependent immunity. Fecal microbiota transplantation (FMT) or L.intestinalis administration inhibited the infiltration of CD8+T cells and macrophages that delayed CP progression. L.intestinalis restrained the recruitment of M1 macrophages and limited the release of Ccl2/7 in the colon, which prevented epithelial damage and epithelial barrier dysfunction through blocking Ccl2/7-Ccr1 signaling. Our findings elucidate that the utilization of statin therapy or supplementation of L.intestinalis can be potential approach for the therapies of CP.

Study protocol: Fecal Microbiota Transplant combined with Atezolizumab/Bevacizumab in Patients with Hepatocellular Carcinoma who failed to achieve or maintain objective response to Atezolizumab/Bevacizumab - the FAB-HCC pilot study

BACKGROUND

The gut microbiota is often altered in chronic liver diseases and hepatocellular carcinoma (HCC), and increasing evidence suggests that it may influence response to cancer immunotherapy. Strategies to modulate the gut microbiome (i.e., fecal microbiota transplant (FMT)) may help to improve efficacy of immune checkpoint inhibitors (ICIs) or even overcome resistance to ICIs. Here, we describe the design and rationale of FAB-HCC, a single-center, single-arm, phase II pilot study to assess safety, feasibility, and efficacy of FMT from patients with HCC who responded to PD-(L)1-based immunotherapy or from healthy donors to patients with HCC who failed to achieve or maintain a response to atezolizumab plus bevacizumab.

METHODS

In this single-center, single-arm, phase II pilot study (ClinicalTrials.gov identifier: NCT05750030), we plan to include 12 patients with advanced HCC who failed to achieve or maintain a response to atezolizumab/bevacizumab. Patients will receive a single FMT via colonoscopy from donors with HCC who responded to PD-(L)1-based immunotherapy or from healthy individuals, followed by atezolizumab/bevacizumab every 3 weeks. The primary endpoint is safety, measured by incidence and severity of treatment-related adverse events. The main secondary endpoint is efficacy, as assessed by best radiological response according to RECISTv1.1 and mRECIST. Additional exploratory endpoints include data on the effect of FMT on recipient gut microbiota, as well as metagenomic analysis of stool samples, analyses of circulating immune cells and serum and stool proteomic, metabolomic and lipidomic signatures.

DISCUSSION

The results of this study will help to define the potential of FMT as add-on intervention in the systemic treatment of advanced HCC, with the potential to improve efficacy of immunotherapy or even overcome resistance.

TRIAL REGISTRATION

EudraCT Number: 2022-000234-42 Clinical trial registry & ID: ClinicalTrials.gov identifier: NCT05750030 (Registration date: 16.01.2023).

The impact of metabolic reprogramming on tertiary lymphoid structure formation: enhancing cancer immunotherapy

BACKGROUND

Cancer immunotherapy has achieved unprecedented success in the field of cancer therapy. However, its potential is constrained by a low therapeutic response rate.

MAIN BODY

Tertiary lymphoid structure (TLS) plays a crucial role in antitumor immunity and is associated with a good prognosis. Metabolic reprogramming, as a hallmark of the tumor microenvironment, can influence tumor immunity and promote the formation of follicular helper T cells and germinal centers. However, many current studies focus on the correlation between metabolism and TLS formation factors, and there is insufficient direct evidence to suggest that metabolism drives TLS formation. This review provided a comprehensive summary of the relationship between metabolism and TLS formation, highlighting glucose metabolism, lipid metabolism, amino acid metabolism, and vitamin metabolism.

CONCLUSIONS

In the future, an in-depth exploration of how metabolism affects cell interactions and the role of microorganisms in TLS will significantly advance our understanding of metabolism-enhanced antitumor immunity.

Diet-microbiome interactions in cancer

Diet impacts cancer in diverse manners. Multiple nutritional effects on tumors are mediated by dietary modulation of commensals, residing in mucosal surfaces and possibly also within the tumor microenvironment. Mechanistically understanding such diet-microbiome-host interactions may enable to develop precision nutritional interventions impacting cancer development, dissemination, and treatment responses. However, data-driven nutritional strategies integrating diet-microbiome interactions are infrequently incorporated into cancer prevention and treatment schemes. Herein, we discuss how dietary composition affects cancer-related processes through alterations exerted by specific nutrients and complex foods on the microbiome. We highlight how dietary timing, including time-restricted feeding, impacts microbial function in modulating cancer and its therapy. We review existing and experimental nutritional approaches aimed at enhancing microbiome-mediated cancer treatment responsiveness while minimizing adverse effects, and address challenges and prospects in integrating diet-microbiome interactions into precision oncology. Collectively, mechanistically understanding diet-microbiome-host interactomes may enable to achieve a personalized and microbiome-informed optimization of nutritional cancer interventions.

Navigating established and emerging biomarkers for immune checkpoint inhibitor therapy

Immune checkpoint inhibitors (ICIs) have improved outcomes of patients with many different cancers. These antibodies target molecules such as programmed cell death 1 (PD-1) or cytotoxic T lymphocyte associated protein 4 (CTLA-4) which normally function to limit immune activity. Treatment with ICIs reactivates T cells to destroy tumor cells in a highly specific manner, which in some patients, results in dramatic remissions and durable disease control. Over the last decade, much effort has been directed at characterizing factors that drive efficacy and resistance to ICI therapy. Food and Drug Administration (FDA)-approved biomarkers for ICI therapy have facilitated more judicious treatment of cancer patients and transformed the field of precision oncology. Yet, adaptive immunity against cancers is complex, and newer data have revealed the potential utility of other biomarkers. In this review, we discuss the utility of currently approved biomarkers and highlight how emerging biomarkers can further improve the identification of patients who benefit from ICIs.

Gut commensal Bifidobacterium-derived extracellular vesicles modulate the therapeutic effects of anti-PD-1 in lung cancer

Lung cancer is the leading cause of cancer-related deaths worldwide. Although immunotherapy such as anti-programmed death-1 and its ligand 1 (PD-1/L1) is a standard treatment for advanced non-small cell lung cancer (NSCLC), many patients do not derive benefit directly. Several studies have elucidated new strategies to improve the antitumor immune response through gut microbiota modulation. However, it remains largely debatable regarding how gut microbiota remotely affect lung cancer microenvironment and subsequently modulate immunotherapy response. Here we show that commensal Bifidobacterium-derived extracellular vesicles (Bif.BEVs) can modulate the therapeutic effect of anti-PD-1 therapy in NSCLC. These Bif.BEVs are up-taken by lung cancer cells predominantly via dynamin-dependent endocytosis and upregulate PD-L1 expression through TLR4-NF-κB pathway. They also efficiently penetrate murine intestinal and patient-derived lung cancer organoids. Oral gavage of these Bif.BEVs result in their accumulation in tumors in mice. Using a syngeneic mouse model, Bif.BEVs are found to synergize the anti-tumor effect of anti-PD-1 via modulation of key cytokines, immune response and oncogenic pathways, and increase in tumor-infiltrating CD8+ T cells. Our study therefore identifies a link between Bif.BEVs and the tumor microenvironment, providing an alternative mechanism to explain how gut microbiota can influence immunotherapy response, particularly in tumors located anatomically distant from the gut.

Coupling culturomics and metagenomics sequencing to characterize the gut microbiome of patients with cancer treated with immune checkpoint inhibitors

BACKGROUND

The gut microbiome represents a novel biomarker for melanoma and non-small cell lung cancer (NSCLC) patients treated with immune checkpoint inhibitors (ICI). Gut microbiome metagenomics profiling studies of patients treated with immunotherapy identified bacteria associated with ICI efficacy, while others have been linked to resistance. However, limitations of metagenomics sequencing, such as complex bioinformatic processing requirements, necessity of a threshold for positive detection, and the inability to detect live organisms, have hindered our ability to fully characterize the gut microbiome. Therefore, combining metagenomics with high-throughput culture-based techniques (culturomics) represents an ideal strategy to fully characterize microbiome composition to more robustly position the microbiome as a biomarker of response to ICI.

METHODS

We performed culturomics using fecal samples from 22 patients from two academic centres in Canada and the United Kingdom with NSCLC and cutaneous melanoma treated with ICI (cancer group), comparing their microbiome composition to that of 7 healthy volunteers (HV), along with matching shotgun metagenomics sequencing.

RESULTS

For culturomics results, 221 distinct species were isolated. Among these 221 distinct species, 182 were identified in the cancer group and 110 in the HV group. In the HV group, the mean species richness was higher compared to the cancer group (34 vs. 18, respectively, p = 0.002). Beta diversity revealed separate clusters between groups (p = 0.004). Bifidobacterium spp. and Bacteroides spp. were enriched in HV, while cancer patients showed an overrepresentation of Enterocloster species, as well as Veillonella parvula. Next, comparing cancer patients' clinical outcomes to ICI, we observed that among the 20 most abundant bacteria present in non-responder patients, 2 belonged to the genus Enterocloster, along with an enrichment of Hungatella hathewayi and Cutibacterium acnes. In contrast, responders to ICI exhibited a predominance of Bacteroides spp. In NSCLC patients, metagenomics analysis revealed that of the 154 bacteria species isolated through culturomics, 61/154 (39%) were also identified by metagenomics sequencing. Importantly, 94 individual species were uniquely detected by culturomics.

CONCLUSION

These findings highlight that culturomics and metagenomics can serve as complementary tools to characterize the microbiome in patients with cancer. This integrated approach uncovers specific microbiome signatures that differentiate HV from cancer patients, and identifies specific species associated with therapy response and resistance.

Fecal microbiota transplantation enhanced the effect of chemoimmunotherapy by restoring intestinal microbiota in LLC tumor-bearing mice

OBJECTIVE

To assess the effect of half-dose chemotherapy (HDC) and standard-dose chemotherapy (SDC) on the intestinal microbiota and to investigate whether fecal microbiota transplantation (FMT) can restore the intestinal microecology to enhance the efficacy of chemoimmunotherapy containing an anti-PD- 1 antibody (PD1).

METHODS

Lewis lung cancer (LLC) tumor-bearing mice were divided into six groups, including Control, HDC, SDC, SDC + FMT, SDC + PD1, and SDC + PD1 + FMT. After the treatment, analyses were conducted on intestinal microbiota using 16S rRNA sequencing, immune cells through flow cytometry, cytokines and chemokines via polymerase chain reaction (PCR), and programmed death-ligand 1 (PD-L1) expression in tumor tissues by immunohistochemistry.

RESULTS

Alpha and beta diversity of intestinal flora were not significantly different between HDC and SDC groups, nor was there a significant difference in the abundance of the top 10 species at the phylum, class, order, family, genus, or species levels. FMT increased both alpha and beta diversity and led to an increase in the abundance of Ruminococcus_callidus and Alistipes_finegoldii at the species level in mice receiving SDC + FMT. Besides, tumor growth was significantly slowed in SDC + PD1 + FMT compared to SDC + PD1 group, accompanied by an up-regulated Bacteroidetes/Firmicutes ratio, down-regulated abundance of Proteobacteria species (including Pseudolabrys, Comamonas, Alcaligenaceae, Xanthobacteraceae and Comamonadaceae), as well as Faecalicoccus of Firmicutes, the increased number of cDC1 cells, cDC2 cells, CD4+ T cells and CD8+ T cells in the peripheral blood, and IFN-γ+CD8+ T cells, IFN-γ, granzyme B, TNF-α, CXCL9 and CXCL10 in intestinal tissues.

CONCLUSIONS

There were no significant differences between HDC and SDC in their effects on the intestinal microbiota. FMT exhibited a beneficial impact on gut microbiota and improved the efficacy of chemoimmunotherapy, possibly associated with the increase of immune cells and the modulation of related cytokines and chemokines.

Cell Death Modalities in Therapy of Melanoma

Melanoma, one of the most lethal cancers, demands urgent and effective treatment strategies. However, a successful therapeutic approach requires a precise understanding of the mechanisms underlying melanoma initiation and progression. This review provides an overview of melanoma pathogenesis, identifies current pathogenic factors contributing to mortality, and explores targeted therapy and checkpoint inhibitor therapy. Furthermore, we examine melanoma classification and corresponding therapies, along with advancements in various cell death mechanisms for melanoma treatment. We also discuss the current treatment status along with some drawbacks encountered during research stages such as resistance and metastasis.

Optimizing Cancer Treatment Through Gut Microbiome Modulation

The gut microbiome plays a pivotal role in modulating cancer therapies, including immunotherapy and chemotherapy. Emerging evidence demonstrates its influence on treatment efficacy, immune response, and resistance mechanisms. Specific microbial taxa enhance immune checkpoint inhibitor efficacy, while dysbiosis can contribute to adverse outcomes. Chemotherapy effectiveness is also influenced by microbiome composition, with engineered probiotics and prebiotics offering promising strategies to enhance drug delivery and reduce toxicity. Moreover, microbial metabolites, such as short-chain fatty acids, and engineered microbial systems have shown potential to improve therapeutic responses. These findings underscore the importance of personalized microbiome-based approaches in optimizing cancer treatments.