Modulating gut microbiome in cancer immunotherapy: Harnessing microbes to enhance treatment efficacy

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 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.

Vitamins and dietary supplements in cancer treatment: is there a need for increased usage?

INTRODUCTION

Vitamins are essential for homeostasis and proper functioning of organisms. These micronutrients prevent tumor onset by functioning as antioxidants and enzymatic cofactors involved in anti-stress and immune responses, modulating epigenetic regulators, and shaping the microbiota composition. Unbalanced diets and sedentary lifestyles contribute to obesity, associated with increasing cancer risk. Cancer patients often exhibit vitamin deficiencies due to chronic inflammation, anticancer therapies, and tumor-induced metabolic changes, leading to malnutrition and cachexia.

AREAS COVERED

This review critically analyzes preclinical and clinical studies, sourced from PubMed and ClinicalTrials.gov databases, that investigate the potential benefits of vitamin supplementation and dietary interventions, such as intermittent fasting and ketogenic diets, in mouse tumor models and cancer patients. This analysis elucidates the limitations of such interventions and suggests optimal dietary strategies to prevent cancer and enhance patients' quality of life and prognosis.

EXPERT OPINION

To date, clinical studies have found no substantial benefit of over-the-counter vitamin supplements and dietary interventions on cancer patients' health and prognosis. To prevent the spread of useless and potentially harmful products by the nutraceutical industry, establishing a regulatory authority is necessary to monitor and ensure product quality and validity before commercialization.

Novel clinical trial designs emerging from the molecular reclassification of cancer

Next-generation sequencing has revealed the disruptive reality that advanced/metastatic cancers have complex and individually distinct genomic landscapes, necessitating a rethinking of treatment strategies and clinical trial designs. Indeed, the molecular reclassification of cancer suggests that it is the molecular underpinnings of the disease, rather than the tissue of origin, that mostly drives outcomes. Consequently, oncology clinical trials have evolved from standard phase 1, 2, and 3 tissue-specific studies; to tissue-specific, biomarker-driven trials; to tissue-agnostic trials untethered from histology (all drug-centered designs); and, ultimately, to patient-centered, N-of-1 precision medicine studies in which each patient receives a personalized, biomarker-matched therapy/combination of drugs. Innovative technologies beyond genomics, including those that address transcriptomics, immunomics, proteomics, functional impact, epigenetic changes, and metabolomics, are enabling further refinement and customization of therapy. Decentralized studies have the potential to improve access to trials and precision medicine approaches for underserved minorities. Evaluation of real-world data, assessment of patient-reported outcomes, use of registry protocols, interrogation of exceptional responders, and exploitation of synthetic arms have all contributed to personalized therapeutic approaches. With greater than 1 × 1012 potential patterns of genomic alterations and greater than 4.5 million possible three-drug combinations, the deployment of artificial intelligence/machine learning may be necessary for the optimization of individual therapy and, in the near future, also may permit the discovery of new treatments in real time.

Unveiling the microbial orchestra: exploring the role of microbiota in cancer development and treatment

The human microbiota comprises a diverse microbial ecosystem that significantly impacts health and disease. Among its components, the gut microbiota plays a crucial role in regulating metabolic, immunologic, and inflammatory responses. Dysbiosis, an imbalance in microbial composition, has been linked to carcinogenesis through mechanisms such as chronic inflammation, metabolic disturbances, epigenetic modifications, and immune system dysregulation. Additionally, dysbiosis influences the efficacy and toxicity of cancer therapies. Given these associations, there is growing interest in leveraging the microbiota as a biomarker for cancer detection and outcome prediction. Notably, distinct microbial signatures have been identified across various cancer types, suggesting their potential as diagnostic markers. Furthermore, modulation of the microbiota presents a promising avenue for improving cancer treatment outcomes through strategies such as antibiotics, prebiotics, probiotics, fecal microbiota transplantation, dietary interventions, small-molecule inhibitors, and phage therapy. To explore these relationships, we conducted a comprehensive literature review using Web of Science, Scopus, PubMed, MEDLINE, Embase, and Google Scholar as our primary online databases, focusing on indexed peer-reviewed articles up to the present year. This review aims to elucidate the role of dysbiosis in cancer development, examine the molecular mechanisms involved, and assess the impact of microbiota on cancer therapies. Additionally, we highlight microbiota-based therapeutic strategies and discuss their potential applications in cancer management. A deeper understanding of the intricate interplay between the microbiota and cancer may pave the way for novel approaches to cancer prevention, early detection, and treatment optimization.

Therapeutic targeting of the host-microbiota-immune axis: implications for precision health

The human body functions as a complex ecosystem, hosting trillions of microbes that collectively form the microbiome, pivotal in immune system regulation. The host-microbe immunological axis maintains homeostasis and influences key physiological processes, including metabolism, epithelial integrity, and neural function. Recent advancements in microbiome-based therapeutics, including probiotics, prebiotics and fecal microbiota transplantation, offer promising strategies for immune modulation. Microbial therapies leveraging microbial metabolites and engineered bacterial consortia are emerging as novel therapeutic strategies. However, significant challenges remain, including individual microbiome variability, the complexity of host-microbe interactions, and the need for precise mechanistic insights. This review comprehensively examines the host microbiota immunological interactions, elucidating its mechanisms, therapeutic potential, and the future directions of microbiome-based immunomodulation in human health. It will also critically evaluate challenges, limitations, and future directions for microbiome-based precision medicine.

Gut Microbiota and Colorectal Cancer: A Balance Between Risk and Protection

The gut microbiome, a complex community of microorganisms residing in the intestinal tract, plays a dual role in colorectal cancer (CRC) development, acting both as a contributing risk factor and as a protective element. This review explores the mechanisms by which gut microbiota contribute to CRC, emphasizing inflammation, oxidative stress, immune evasion, and the production of genotoxins and microbial metabolites. Fusobacterium nucleatum, Escherichia coli (pks+), and Bacteroides fragilis promote tumorigenesis by inducing chronic inflammation, generating reactive oxygen species, and producing virulence factors that damage host DNA. These microorganisms can also evade the antitumor immune response by suppressing cytotoxic T cell activity and increasing regulatory T cell populations. Additionally, microbial-derived metabolites such as secondary bile acids and trimethylamine-N-oxide (TMAO) have been linked to carcinogenic processes. Conversely, protective microbiota, including Lactobacillus, Bifidobacterium, and Faecalibacterium prausnitzii, contribute to intestinal homeostasis by producing short-chain fatty acids (SCFAs) like butyrate, which exhibit anti-inflammatory and anti-carcinogenic properties. These beneficial microbes enhance gut barrier integrity, modulate immune responses, and inhibit tumor cell proliferation. Understanding the dynamic interplay between pathogenic and protective microbiota is essential for developing microbiome-based interventions, such as probiotics, prebiotics, and fecal microbiota transplantation, to prevent or treat CRC. Future research should focus on identifying microbial biomarkers for early CRC detection and exploring personalized microbiome-targeted therapies. A deeper understanding of host-microbiota interactions may lead to innovative strategies for CRC management and improved patient outcomes.

Regulating the Tumor Microbiome through Near-Infrared-III Light-Excited Photosynthesis

Tumor microbiomes are increasingly associated with the growth and metastasis of tumors. Exploring the regulation of the tumor microbiome through therapeutics is an area of interest in cancer therapy. In this study, the authors have investigated a biohybrid with 1550 nm light-excited photosynthetic ability to regulate the tumor microbiome. This system utilizes Er-based core-shell upconversion nanoparticles to arm microalga Chlorella, enabling the rapid evolution of Chlorella to perform oxygenic photosynthesis under 1550 nm light excitation. This biohybrid may alleviate hypoxia within the tumor microenvironment and induce significant changes in the tumor microbiome, ultimately resulting in marked inhibition of tumor growth. Benefiting from the strong tissue penetration ability of 1550 nm light, this biohybrid also exhibits clear inhibition of deep-seated tumors. The therapeutic efficacy of microbiome regulation is directly mediated by immune activation, converting "cold" tumors into "hot" tumors, which also leads to a long-lasting immune memory effect.

Fasting-mimicking diet-enriched Bifidobacterium pseudolongum suppresses colorectal cancer by inducing memory CD8+ T cells

BACKGROUND

Fasting-mimicking diet (FMD) boosts the antitumour immune response in patients with colorectal cancer (CRC). The gut microbiota is a key host immunity regulator, affecting physiological homeostasis and disease pathogenesis.

OBJECTIVE

We aimed to investigate how FMD protects against CRC via gut microbiota modulation.

DESIGN

We assessed probiotic species enrichment in FMD-treated CRC mice using faecal metagenomic sequencing. The candidate species were verified in antibiotic-treated conventional and germ-free mouse models. Immune landscape alterations were evaluated using single-cell RNA sequencing and multicolour flow cytometry. The microbiota-derived antitumour metabolites were identified using metabolomic profiling.

RESULTS

Faecal metagenomic profiling revealed Bifidobacterium pseudolongum enrichment in FMD-treated CRC mice. B. pseudolongum mediates the FMD antitumour effects by increasing the tissue-resident memory CD8+ T-cell (TRM) population in CRC mice. The level of L-arginine, a B. pseudolongum functional metabolite, increased in FMD-treated CRC mice; furthermore, L-arginine induced the TRM phenotype in vivo and in vitro. Mechanistically, L-arginine is transported by the solute carrier family 7-member 1 (SLC7A1) receptor in CD8+ T cells. Both FMD and B. pseudolongum improved anti-CTLA-4 efficacy in the orthotopic mouse CRC model. In FMD-treated patients with CRC, the CD8+ TRM cell number increased as B. pseudolongum and L-arginine accumulated. The abundance of CD8+ TRM cells and B. pseudolongum was associated with a better prognosis in patients with CRC.

CONCLUSION

B. pseudolongum contributes to the FMD antitumour effects in CRC by producing L-arginine. This promotes CD8+ T-cell differentiation into memory cells. B. pseudolongum administration is a potential CRC therapeutic strategy.

The gut microbiome and dietary fibres: implications in obesity, cardiometabolic diseases and cancer

Dietary fibres constitute a heterogeneous class of nutrients that are key in the prevention of various chronic diseases. Most dietary fibres are fermented by the gut microbiome and may, thereby, modulate the gut microbial ecology and metabolism, impacting human health. Dietary fibres may influence the occurrence of specific bacterial taxa, with this effect varying between individuals. The effect of dietary fibres on microbial diversity is a matter of debate. Most intervention studies with dietary fibres in the context of obesity and related metabolic disorders reveal the need for an accurate assessment of the microbiome to better understand the variable response to dietary fibres. Epidemiological studies confirm that a high dietary fibre intake is strongly associated with a reduced occurrence of many types of cancer. However, there is a need to determine the impact of intervention with specific dietary fibres on cancer risk, therapy efficacy and toxicity, as well as in cancer cachexia. In this Review, we summarize the mechanisms by which the gut microbiome can mediate the physiological benefits of dietary fibres in the contexts of obesity, cardiometabolic diseases and cancer, their incidence being clearly linked to low dietary fibre intake.

Outer membrane vesicles in gram-negative bacteria and its correlation with pathogenesis

There is a widespread distribution of gram-negative bacteria worldwide, which are responsible for the deaths of numerous patients each year. The illnesses they cause can be localized and systemic, and these bacteria possess several key virulence factors that contribute to their pathogenicity. In recent years, several distinct mechanisms of pathogenesis have evolved that remain largely unknown to scientists and medical experts. Among these, outer membrane vesicles (OMVs) are undoubtedly one of the most significant factors influencing virulence. OMVs contain various bacterial compounds and can have diverse effects on host organisms and the immune system, potentially exacerbating disease and inflammation while evading immune responses. This review comprehensively examines the role of OMVs in bacterial pathogenesis, their interaction with host cells, and their potential biomedical applications. Understanding the molecular mechanisms governing OMV biogenesis and function could pave the way for novel antimicrobial strategies and therapeutic interventions.

Host-microbe-cancer interactions on-a-chip

The tumor microbiota has emerged as a pivotal contributor to a variety of cancers, impacting disease development, progression, and therapeutic resistance. Due to the complexity of the tumor microenvironment, reproducing the interactions between the microbes, tumor cells, and the immune system remains a great challenge for both in vitro and in vivo studies. To this end, significant progress has been made toward leveraging tumor-on-a-chip model systems to replicate critical hallmarks of the native disease in vitro. These microfluidic platforms offer the ability to mimic essential components of the tumor microenvironment, including controllable fluid flow conditions, manipulable extracellular matrix dynamics, and intricate 3D multi-cellular communication. The primary objective of this review is to discuss recent challenges and advances in engineering host-microbiota and tumor interactions on-a-chip. Ultimately, overcoming these obstacles will help us gain deeper insights into tumor-microbe interactions and enhance avenues for developing more effective cancer therapies.

Operationalizing Team Science at the Academic Cancer Center Network to Unveil the Structure and Function of the Gut Microbiome

Oncologists increasingly recognize the microbiome as an important facilitator of health as well as a contributor to disease, including, specifically, cancer. Our knowledge of the etiologies, mechanisms, and modulation of microbiome states that ameliorate or promote cancer continues to evolve. The progressive refinement and adoption of "omic" technologies (genomics, transcriptomics, proteomics, and metabolomics) and utilization of advanced computational methods accelerate this evolution. The academic cancer center network, with its immediate access to extensive, multidisciplinary expertise and scientific resources, has the potential to catalyze microbiome research. Here, we review our current understanding of the role of the gut microbiome in cancer prevention, predisposition, and response to therapy. We underscore the promise of operationalizing the academic cancer center network to uncover the structure and function of the gut microbiome; we highlight the unique microbiome-related expert resources available at the City of Hope of Comprehensive Cancer Center as an example of the potential of team science to achieve novel scientific and clinical discovery.

Role of human microbiota in facilitating the metastatic journey of cancer cells

Cancer continues to be the leading cause of mortality worldwide, with metastasis being the primary contributor to cancer-related deaths. Despite significant advancements in cancer therapies, metastasis remains a major challenge in effective cancer management. Metastasis, the process by which cancer cells spread from the primary tumor to distant organs, is a complex phenomenon influenced by multiple factors, including the human microbiota. The human body encompasses various microorganisms, comprising bacteria, viruses, fungi, and protozoa, collectively known as microbiota. In fact, the microbiota is more abundant than human cells, and its disruption, leading to an imbalance in host-microbiota interactions (dysbiosis), has been linked to various diseases, including cancer. Among all microbiota, bacteria are one of the key contributors to cancer progression. Bacteria and bacteria-derived components such as secondary metabolites, QSPs, and toxins play a pivotal role in the metastatic progression of cancers. This review explores the intricate relationship between the human microbiota and cancer progression, focusing on different bacterial species which have been implicated in tumorigenesis, immune evasion, and metastasis. The present review explores the role of the human microbiome, specifically of bacteria in promoting metastasis in different types of cancers, demonstrating its ability to impact both the spread of tumors and their underlying mechanisms. This review also highlights the therapeutic potential and challenges of microbiome-based interventions in combating metastatic cancers. By addressing these challenges and by integrating microbiome-targeted strategies into clinical cancer treatment could represent a transformative approach in the fight against metastasis.

Harnessing Lactobacillus reuteri-Derived Extracellular Vesicles for Multifaceted Cancer Treatment

Extracellular vesicles (EVs) have emerged as valuable biological materials for treating intractable diseases. Extensive studies are conducted on EVs derived from various cellular sources. In this study, EVs derived from Lactobacillus reuteri (L. reuteri), a probiotic, exhibit remarkable cancer therapeutic efficacy when administered orally is reported. These L. reuteri-derived EVs (REVs) demonstrate stability in the gastrointestinal tract and exert significant anti-tumor effects. Using A549 cells and murine models, we confirmed that REVs mediate their therapeutic effects by modulating apoptotic signaling pathways. Furthermore, the combination of REV with drugs enhances tumor ablation and induces immunogenic cell death. In a mouse model, oral administration of REVs encapsulating indocyanine green followed by photothermal therapy led to complete tumor elimination within 32 days. REVs represent a promising biological therapeutic platform for cancer treatment, either independently or in combination with other therapies, depending on the treatment objectives.

Current status and future perspectives of immunotherapy for abdominal liposarcoma: From basic research to clinical practice

Liposarcoma is a highly heterogeneous type of soft tissue sarcoma originating from adipose tissue, characterized by complex biological behavior and invasiveness. Traditional treatments have shown limited efficacy in high-grade and metastatic liposarcoma, with unsatisfactory patient outcomes. In recent years, the breakthroughs of immunotherapy in various solid tumors have sparked interest in its potential application to liposarcoma. This review systematically examines the progress in basic research and clinical practice of immunotherapy for liposarcoma, discussing the tumor immune microenvironment, mechanisms of immune evasion, the application of immune checkpoint inhibitors, combination therapy strategies, the challenges faced, as well as the future direction, with an aim to provide a theoretical basis for personalized treatment of liposarcoma, promote the development of novel immunotherapy strategies, and ultimately improve patient prognosis and quality of life.

Skin microbiome and dermatologic disorders

Human skin acts as a physical barrier to prevent the entry of pathogenic microbes while simultaneously providing a home for commensal bacteria and fungi. Microbiome sequencing studies have demonstrated the unappreciated diversity and selectivity of these microbes. Functional studies have demonstrated the impact of specific strains to tune the immune system, sculpt the microbial community, provide colonization resistance, and promote epidermal barrier integrity. Recent studies have integrated the microbiome, immunity, and tissue integrity to understand their interplay in common disorders such as atopic dermatitis. In this Review, we explore microbiome shifts associated with cutaneous disorders with an eye toward how the microbiome can be mined to identify new therapeutic opportunities.

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.

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.

Gut Microbiota-Tumor Microenvironment Interactions: Mechanisms and Clinical Implications for Immune Checkpoint Inhibitor Efficacy in Cancer

Cancer immunotherapy has transformed cancer treatment in recent years, with immune checkpoint inhibitors (ICIs) emerging as a key therapeutic approach. ICIs work by inhibiting the mechanisms that allow tumors to evade immune detection. Although ICIs have shown promising results, especially in solid tumors, patient responses vary widely due to multiple intrinsic and extrinsic factors within the tumor microenvironment. Emerging evidence suggests that the gut microbiota plays a pivotal role in modulating immune responses at the tumor site and may even influence treatment outcomes in cancer patients receiving ICIs. This review explores the complex interactions between the gut microbiota and the tumor microenvironment, examining how these interactions could impact the effectiveness of ICI therapy. Furthermore, we discuss how dysbiosis, an imbalance in gut microbiota composition, may contribute to resistance to ICIs, and highlight microbiota-targeted strategies to potentially overcome this challenge. Additionally, we review recent studies investigating the diagnostic potential of microbiota profiles in cancer patients, considering how microbial markers might aid in early detection and stratification of patient responses to ICIs. By integrating insights from recent preclinical and clinical studies, we aim to shed light on the potential of microbiome modulation as an adjunct to cancer immunotherapy and as a diagnostic tool, paving the way for personalized therapeutic approaches that optimize patient outcomes.

Polysaccharides from Sea Cucumber (Stichopus japonicus) Synergize with Anti-PD1 Immunotherapy to Reduce MC-38 Tumor Burden in Mice Through Shaping the Gut Microbiome

Immune checkpoint inhibitors (ICIs) have revolutionized cancer treatment and significantly improved outcomes for patients with certain malignancies. However, immunotherapy with ICIs is only effective in a subset of patients and the gut microbiota have been identified as an important factor associated with response to ICI therapy. Polysaccharides from sea cucumber (Stichopus japonicus) (SCP) have been shown to modulate the gut microbiota and exhibit beneficial health functions, but whether SCP could synergize with anti-PD1 immunotherapy remains unexplored. In this study, mice with ICI-sensitive MC38 tumors were treated with anti-PD1 antibody after supplementation with or without SCP to examine the potential impact of SCP on the efficacy of immunotherapy. SCP strongly amplified the anti-tumor activity of anti-PD1 in MC38 tumor-bearing mice. Flow cytometry and immunohistological staining demonstrated that SCP treatment increased cytotoxic CD8+ T lymphocytes while decreasing regulatory Foxp3+ CD4+ T lymphocytes. Gut microbiota and metabolomic analysis revealed that SCP modulated the microbiota and increased the abundance of certain metabolites such as indole-3-carboxylic acid. Furthermore, fecal microbiota transplantation experiments justified that the synergistic effect of SCP with anti-PD1 was partially mediated through the gut microbiota. Mice receiving microbiota from SCP-treated mice showed a boosted response to anti-PD1, along with enhanced anti-tumor immunity. These findings indicate that SCP could be utilized as a dietary strategy combined with anti-PD1 therapy to achieve improved outcomes in patients.

Resistance mechanisms to immune checkpoint inhibitors: updated insights

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

Harnessing the tumor microenvironment: targeted cancer therapies through modulation of epithelial-mesenchymal transition

The tumor microenvironment (TME) is integral to cancer progression, impacting metastasis and treatment response. It consists of diverse cell types, extracellular matrix components, and signaling molecules that interact to promote tumor growth and therapeutic resistance. Elucidating the intricate interactions between cancer cells and the TME is crucial in understanding cancer progression and therapeutic challenges. A critical process induced by TME signaling is the epithelial-mesenchymal transition (EMT), wherein epithelial cells acquire mesenchymal traits, which enhance their motility and invasiveness and promote metastasis and cancer progression. By targeting various components of the TME, novel investigational strategies aim to disrupt the TME's contribution to the EMT, thereby improving treatment efficacy, addressing therapeutic resistance, and offering a nuanced approach to cancer therapy. This review scrutinizes the key players in the TME and the TME's contribution to the EMT, emphasizing avenues to therapeutically disrupt the interactions between the various TME components. Moreover, the article discusses the TME's implications for resistance mechanisms and highlights the current therapeutic strategies toward TME modulation along with potential caveats.

Unveiling the Interplay Between the Human Microbiome and Gastric Cancer: A Review of the Complex Relationships and Therapeutic Avenues

The human microbiota plays a crucial role in maintaining overall health and well-being. The gut microbiota has been implicated in developing and progressing various diseases, including cancer. This review highlights the related mechanisms and the compositions that influence cancer pathogenesis with a highlight on gastric cancer. We provide a comprehensive overview of the mechanisms by which the microbiome influences cancer development, progression, and response to treatment, with a focus on identifying potential biomarkers for early detection, prevention strategies, and novel therapeutic interventions that leverage microbiome modulation. This comprehensive review can guide future research and clinical practices in understanding and harnessing the microbiome to optimize gastric cancer therapies.

Therapeutic Modulation of the Microbiome in Oncology: Current Trends and Future Directions

Cancer is a predominant cause of mortality worldwide, necessitating the development of innovative therapeutic techniques. The human microbiome, particularly the gut microbiota, has become a significant element in cancer research owing to its essential role in sustaining health and influencing disease progression. This review examines the microbiome's makeup and essential functions, including immunological modulation and metabolic regulation, which may be evaluated using sophisticated methodologies such as metagenomics and 16S rRNA sequencing. The microbiome influences cancer development by promoting inflammation, modulating the immune system, and producing carcinogenic compounds. Dysbiosis, or microbial imbalance, can undermine the epithelial barrier and facilitate cancer. The microbiome influences chemotherapy and radiation results by modifying drug metabolism, either enhancing or reducing therapeutic efficacy and contributing to side effects and toxicity. Comprehending these intricate relationships emphasises the microbiome's significance in oncology and accentuates the possibility for microbiome-targeted therapeutics. Contemporary therapeutic approaches encompass the utilisation of probiotics and dietary components to regulate the microbiome, enhance treatment efficacy, and minimise unwanted effects. Advancements in research indicate that personalised microbiome-based interventions, have the potential to transform cancer therapy, by providing more effective and customised treatment alternatives. This study aims to provide a comprehensive analysis of the microbiome's influence on the onset and treatment of cancer, while emphasising current trends and future possibilities for therapeutic intervention.

Immunobiology of biliary tract cancer and recent clinical findings in approved and upcoming immune checkpoint inhibitors

INTRODUCTION

Recently, immunotherapy has offered new hope for treating biliary tract cancer (BTC). However, several issues are to be considered, including the lack of validated predictive biomarkers that could help to identify patient groups which are most likely to benefit from such therapeutic approaches.

AREAS COVERED

In the current article, we will provide an overview of recent results and ongoing and future research directions of immunotherapy in BTC, with a special focus on recently published, practice-changing data, and ongoing active and recruiting clinical trials.

EXPERT OPINION

At this moment, dozens of clinical trials in phases I to III are evaluating the role of cancer immunotherapy in this setting, with the hope of adding more therapeutic options for BTC patients. Future research must focus on the development of novel agents and combinations, but the validation of biomarkers remains an urgent need. As more research results emerge, novel combinatorial strategies are destined to further transform the treatment paradigm for this heterogeneous and aggressive tumor type.

Modulation of the Immune Environment in Glioblastoma by the Gut Microbiota

Studies increasingly support the role of the gut microbiota in glioma development and treatment, although the exact mechanisms remain unclear. Research indicates that the gut microbiota can influence glioma progression, response to therapies, and the effectiveness of treatments like immunotherapy, with certain microbial compositions being linked to better outcomes. Additionally, the gut microbiota impacts the tumor microenvironment, affecting both tumor growth and the response to treatment. This review will explore glioma, the gut microbiota, and how their interaction shapes glioma development and therapy responses. Additionally, this review examines the influence of gut microbiota metabolites, such as short-chain fatty acids (SCFAs) and tryptophan, on glioma development and treatment. It also explores gut microbiome signaling via pattern recognition receptors, and the role of molecular mimicry between microbial and tumor antigens in glioblastoma, and if these interactions affect glioma development and treatment.

Redefining the tumor microenvironment with emerging therapeutic strategies

The environment surrounding a tumor, known as the tumor microenvironment (TME), plays a role in how cancer progresses and responds to treatment. It poses both challenges and opportunities for improving cancer therapy. Recent progress in understanding the TME complexity and diversity has led to approaches for treating cancer. This perspective discusses the strategies for targeting the TME, such as adjusting networks using extracellular vesicles to deliver drugs and enhancing immune checkpoint inhibitors (ICIS) through combined treatments. Furthermore, it highlights adoptive cell transfer (ACT) therapies as an option for tumors. By studying how components of the TME interact and utilizing technologies like single-cell RNA sequencing and spatial transcriptomics, we can develop more precise and efficient treatments for cancer. This article emphasizes the need to reshape the TME to boost antitumor immunity and overcome resistance to therapy, providing guidance for research and clinical practices in precision oncology.

Gut Microbiota Are a Novel Source of Biomarkers for Immunotherapy in Non-Small-Cell Lung Cancer (NSCLC)

Despite the recent availability of immune checkpoint inhibitors, not all patients affected by Non-Small-Cell Lung Cancer (NSCLC) benefit from immunotherapy. The reason for this variability relies on a variety of factors which may allow for the identification of novel biomarkers. Presently, a variety of biomarkers are under investigation, including the PD1/PDL1 axis, the tumor mutational burden, and the microbiota. The latter is made by all the bacteria and other microorganisms hosted in our body. The gut microbiota is the most represented and has been involved in different physiological and pathological events, including cancer. In this light, it appears that all conditions modifying the gut microbiota can influence cancer, its treatment, and its treatment-related toxicities. The aim of this review is to analyze all the conditions influencing the gut microbiota and, therefore, affecting the response to immunotherapy, iRAEs, and their management in NSCLC patients. The investigation of the landscape of these biological events can allow for novel insights into the optimal management of NSCLC immunotherapy.