Cancer Immunotherapy: Fecal Microbiota Transplantation Brings Light

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.

Research progress on fecal microbiota transplantation in tumor prevention and treatment

The application of fecal microbiota transplantation (FMT) as a therapeutic strategy to directly modify the makeup of the gut microbiota has made significant progress in the last few decades. The gut microbiota, a sizable microbial community present in the human gut, is essential for digestion, immunomodulation, and nutrition absorption. Alternatively, a growing body of research indicates that gut microbiota is a key contributor to cancer, and intratumoral bacteria are considered to be crucial "accomplices" in the development and metastasis of malignancies. The exceptional clinical effectiveness of FMT in treating melanoma patients has been adequately established in earlier research, which has created new avenues for the diagnosis and treatment of cancer and sparked an increasing interest in the treatment and prevention of other cancers. However, further research on the function and mechanisms of the gut microbiota is required to properly comprehend the impact and role of these organisms in tumor regulation. In this article, we present a detailed account of the influence of FMT on the entire course of cancer patients' illness and treatment, from tumor development, metastasis, and invasion, to the impact and application of treatment and prognosis, as well as address the associated mechanisms.

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.

Fecal Microbiota Transplantation Alleviates Airway Inflammation in Asthmatic Rats by Increasing the Level of Short-Chain Fatty Acids in the Intestine

Asthma is a prevalent chronic inflammatory disorder of the respiratory tract that not only manifests with respiratory symptoms but also often involves intestinal flora disorders and gastrointestinal dysfunction. Recent studies have confirmed the close relationship between the gut and lungs, known as the "gut-lung axis" theory. Fecal microbiota transplantation (FMT), a method for restoring normal intestinal flora, has shown promise in treating common gastrointestinal diseases. The "gut-lung axis" theory suggests that FMT may have significant therapeutic potential for asthma. In this study, we established an Ovalbumin (OVA)-induced rat model of asthma to investigate the protective effect of FMT on airway inflammation and the restoration of intestinal short-chain fatty acids (SCFAs), aiming to explore its underlying mechanism. Rats in the Control group underwent fecal treatment via gavage (Control-FMT, C-FMT group), while rats in the Asthma group underwent fecal treatment via gavage after asthma induction (Asthma-FMT, A-FMT group). Following a two-week period of continuous intragastric administration, various measurements were conducted to assess pulmonary function, peripheral blood neutrophil, lymphocyte, and eosinophil content, lung tissue pathology, and collagen fiber deposition in the lungs. Additionally, neutrophil and eosinophil content in bronchoalveolar lavage fluid (BALF), expression levels of Interleukin-4 (IL-4), IL-5, IL-13, IL-17, IL-33, leukotrienes (LT), thymic stromal lymphopoietin (TSLP), prostaglandin D2 (PGD2) protein and mRNA in lung tissue, and SCFAs content in stool were evaluated. In the C-FMT group, lung function significantly improved, inflammatory cell content in peripheral blood and BALF decreased, lung tissue pathology and collagen fiber deposition significantly improved, the protein and mRNA levels of lung inflammatory factors IL-4, IL-5, IL-13, IL-17, IL-33, LT, TSLP, PGD2 were significantly decreased, and SCFAs such as acetate (C2), propionate (C3), butyrate (C4), isobutyric acid (I-C4), valeric acid (C5), and isovaleric acid (I-C5) content in stool significantly increased. However, the indexes in the A-FMT group did not show significant recovery, and the treatment effect on asthma symptoms in rats was inferior to that in the C-FMT group. Asthma induced intestinal flora disorders in rats, and FMT treatment improved the inflammatory response in asthmatic rat models and corrected their intestinal SCFAs disorders. Encouraging the recovery of intestinal SCFAs may play a significant role, and beneficial bacteria present in feces may improve asthma symptoms by promoting the remodeling of intestinal flora. This experiment provides further scientific evidence supporting the "gut-lung axis" theory.

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

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

The bacterial microbiome and cancer: development, diagnosis, treatment, and future directions

The term "microbiome" refers to the collection of bacterial species that reside in the human body's tissues. Sometimes, it is used to refer to all microbial entities (bacteria, viruses, fungi, and others) which colonize the human body. It is now generally acknowledged that the microbiome plays a critical role in the host's physiological processes and general well-being. Changes in the structure and/or function of the microbiome (dysbiosis) are linked to the development of many diseases including cancer. The claim that because of their negatively charged membrane, cancer cells are more vulnerable to some bacteria than normal cells and that is how the link between these bacteria and cancer evolved has been refuted. Furthermore, the relationship between the microbiome and cancer is more evident in the emerging field of cancer immunotherapy. In this narrative review, we detailed the correlation between the presence/absence of specific bacterial species and the development, diagnosis, prognosis, and treatment of some types of cancer including colorectal, lung, breast, and prostate cancer. In addition, we discussed the mechanisms of microbiome-cancer interactions including genotoxin production, the role of free radicals, modification of signaling pathways in host cells, immune modulation, and modulation of drug metabolism by microbiome. Future directions and clinical application of microbiome in the early detection, prognosis, and treatment of cancer emphasizing on the role of fecal transplantation, probiotics, prebiotics, and microbiome biomarkers were also considered.

Fecal Microbiota Transplantation: Insights into Colon Carcinogenesis and Immune Regulation

Colorectal cancer (CRC) constitutes a significant global health challenge, with recent studies underscoring the pivotal role of the gut microbiome in its pathogenesis and progression. Fecal microbiota transplantation (FMT) has emerged as a compelling therapeutic approach, offering the potential to modulate microbial composition and optimize treatment outcomes. Research suggests that specific bacterial strains are closely linked to CRC, influencing both its clinical management and therapeutic interventions. Moreover, the gut microbiome's impact on immunotherapy responsiveness heralds new avenues for personalized medicine. Despite the promise of FMT, safety concerns, particularly in immunocompromised individuals, remain a critical issue. Clinical outcomes vary widely, influenced by genetic predispositions and the specific transplantation methodologies employed. Additionally, rigorous donor selection and screening protocols are paramount to minimize risks and maximize therapeutic efficacy. The current body of literature advocates for the establishment of standardized protocols and further clinical trials to substantiate FMT's role in CRC management. As our understanding of the microbiome deepens, FMT is poised to become a cornerstone in CRC treatment, underscoring the imperative for continued research and clinical validation.

Predictors of response to immunotherapy in colorectal cancer

Colorectal cancer (CRC) is a major cause of cancer-related deaths globally. While treatment advancements have improved survival rates, primarily through targeted therapies based on KRAS, NRAS, and BRAF mutations, personalized treatment strategies for CRC remain limited. Immunotherapy, mainly immune checkpoint blockade, has shown efficacy in various cancers but is effective in only a small subset of patients with CRC with deficient mismatch repair (dMMR) proteins or high microsatellite instability (MSI). Recent research has challenged the notion that CRC is immunologically inert, revealing subsets with high immunogenicity and diverse lymphocytic infiltration. Identifying precise biomarkers beyond dMMR and MSI is crucial to expanding immunotherapy benefits. Hence, exploration has extended to various biomarker sources, such as the tumor microenvironment, genomic markers, and gut microbiota. Recent studies have introduced a novel classification system, consensus molecular subtypes, that aids in identifying patients with CRC with an immunogenic profile. These findings underscore the necessity of moving beyond single biomarkers and toward a comprehensive understanding of the immunological landscape in CRC, facilitating the development of more effective, personalized therapies.

Dual-targeted treatment for inflammatory bowel disease: Whether fecal microbiota transplantation can be an important part of it

Inflammatory bowel disease (IBD) is a chronic gastrointestinal inflammatory disease. With the emergence of biologics and other therapeutic methods, two biologics or one biologic combined with a novel small-molecule drug has been proposed in recent years to treat IBD. Although treatment strategies for IBD are being optimized, their efficacy and risks still warrant further consideration. This editorial explores the current risks associated with dual-targeted treatment for IBD and the great potential that fecal microbiota transplantation (FMT) may have for use in combination therapy for IBD. We are focused on addressing refractory IBD or biologically resistant IBD based on currently available dual-targeted treatment by incorporating FMT as part of this dual-targeted treatment. In this new therapy regimen, FMT represents a promising combination therapy.

Mucosal microbiota characterization in gastric cancer identifies immune-activated-related transcripts relevant gastric microbiome signatures

Tumor microenvironment (TME) immune cells and gastric mucosal microbiome constitute two vital elements of tumor tissue. Increasing evidence has elucidated their clinicopathological significance in predicting outcomes and therapeutic efficacy. However, comprehensive characterization of immune cell-associated microbiome signatures in the TME is still in the early stages of development. Here, we characterized the gastric mucosa microbiome and its associations with immune-activated related transcripts (IATs) in 170 GC tumor tissues and matched non-tumor tissues using 16s rRNA gene sequencing and quantitative reverse transcription-PCR. Microbial diversity and richness were significantly higher in GC tumor tissues than in non-tumor tissues. Differences in microbial composition between the groups were evident, with Firmicutes, Proteobacteria, Bacteroidota, Campilobacterota, Actinobacteria, Fusobacteriota, Verrucomicrobiota, Acidobacteriota, and Cyanobacteria being the dominant phyla in the gastric mucosal microbiota. Microbial interaction network analysis revealed distinctive centralities of oral bacteria (such as Fusobacterium, Porphyromonas, Prevotella, etc.) in both tumor and normal mucosae networks, suggesting their significant influence on GC microbial ecology. Furthermore, we analyzed the expression of IATs (CXCL9, CXCL10, GZMA, GZMB, PRF1, CD8A, IFNG, TBX2, and TNF) and characterized IAT-relevant gastric microbiome signatures in GC patients. Our results showed that the expression of CXCL9, CXCL10, GZMA, GZMB, PRF1 and IFNG was significantly higher in tumor tissues than in adjacent normal tissues in GC patients. Notably, high expression of IATs in tumor tissues was associated with improved survival in GC patients and could serve as a powerful predictor for disease-free survival. Additionally, analysis of IAT levels and mucosal microbiota diversity revealed a correlation between higher IAT expression and increased microbiota richness and evenness in the IATs high group, suggesting potential interactions between mucosal microbiota and tumor immunopathology. Spearman correlation analysis showed positive associations between IAT expression and specific mucosal bacterial species. Notably, Akkermansia muciniphila demonstrated potential involvement in modulating GZMB expression in the GC mucosal microenvironment. These findings underscore the importance of mucosal microbiota alterations in GC and suggest potential therapeutic targets focusing on modulating the tumor microbiota for improved clinical outcomes. The detailed characterization of these elements has profound implications for both treatment and survival prediction in GC. We observed that microbial diversity and richness were significantly higher in GC tumor tissues compared to non-tumor tissues. These differences highlight the unique microbial landscape of GC tumors and suggest that the microbiome could influence tumor development and progression. Importantly, our study demonstrated that high expression levels of IATs in GC tumor tissues were associated with improved patient survival. This suggests that IATs not only reflect immune activation but also serve as valuable biomarkers for predicting disease-free survival. The potential of IATs as predictive markers underscores their utility in guiding therapeutic strategies and personalizing treatment approaches. Moreover, the correlation between higher IAT expression and increased microbiota richness and evenness suggests that a diverse and balanced microbiome may enhance immune responses and contribute to better clinical outcomes. These findings highlight the critical need to consider mucosal microbiota alterations in GC management. Targeting the tumor microbiota could emerge as a promising therapeutic strategy, potentially leading to more effective treatments and improved patient outcomes. Understanding and modulating the microbiome's role in GC opens new avenues for innovative therapeutic interventions and personalized medicine.

Pharmacomicrobiomics in precision cancer therapy: bench to bedside

The burgeoning field of pharmacomicrobiomics offers promising insights into the intricate interplay between the microbiome and cancer, shaping responses to diverse treatment modalities. This review aims to analyze the molecular mechanisms underlying interactions between distinct microbiota types and cancer, as well as their influence on treatment outcomes. We explore how the microbiome impacts antitumor immunity, and response to chemotherapy, immunotherapy, and radiation therapy, unveiling its multifaceted roles in cancer progression and therapy resistance. Moreover, we discuss the challenges hindering the development of microbiome-based interventions in cancer therapy, including standardization, validation, and clinical translation. By synthesizing clinical evidence, we underscore the transformative potential of harnessing pharmacomicrobiomics in guiding cancer treatment decisions, paving the way for improved patient outcomes in clinical practice.

Shaping the future of gastrointestinal cancers through metabolic interactions with host gut microbiota

Gastrointestinal (GI) cancers represent a significant global health challenge, driving relentless efforts to identify innovative diagnostic and therapeutic approaches. Recent strides in microbiome research have unveiled a previously underestimated dimension of cancer progression that revolves around the intricate metabolic interplay between GI cancers and the host's gut microbiota. This review aims to provide a comprehensive overview of these emerging metabolic interactions and their potential to catalyze a paradigm shift in precision diagnosis and therapeutic breakthroughs in GI cancers. The article underscores the groundbreaking impact of microbiome research on oncology by delving into the symbiotic connection between host metabolism and the gut microbiota. It offers valuable insights into tailoring treatment strategies to individual patients, thus moving beyond the traditional one-size-fits-all approach. This review also sheds light on novel diagnostic methodologies that could transform the early detection of GI cancers, potentially leading to more favorable patient outcomes. In conclusion, exploring the metabolic interactions between host gut microbiota and GI cancers showcases a promising frontier in the ongoing battle against these formidable diseases. By comprehending and harnessing the microbiome's influence, the future of precision diagnosis and therapeutic innovation for GI cancers appears more optimistic, opening doors to tailored treatments and enhanced diagnostic precision.

Nutrition Intervention and Microbiome Modulation in the Management of Breast Cancer

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

Immunotherapy for renal cell carcinoma: New therapeutic combinations and adverse event management strategies: A review

Immune checkpoint inhibitor (ICI) combinations, as well as ICIs combined with tyrosine kinase inhibitors, have considerable potential for renal cell carcinoma (RCC) treatment. Newer targeted medications, gut microbiome, nanomedicines, and cyclin-dependent kinase (CDK) inhibitors demonstrate significant potential in preventing side effects and resistance associated with RCC treatment. Most patients, including those demonstrating long-term treatment effects, eventually demonstrate cancer progression. Nevertheless, recent studies have further revealed RCC pathogenesis and many acquired drug resistance mechanisms, which together have led to the identification of promising therapeutic targets. In addition to having roles in metabolism, immunogenicity, and the immune response to tumors, CDK4 and CDK6 regulate the cell cycle. Targeting CDK4 and CDK6, either separately or in combination with already approved treatments, may improve therapeutic outcomes in patients with kidney cancer. Other novel drugs, including pegylated interleukin 10, colony-stimulating factor 1 receptor inhibitors, CD40 agonists, and C-X-C receptor 4 inhibitors affect the tumor microenvironment and cancer cell metabolism. Moreover, a triple ICI combination has been noted to be efficacious. In general, compared with sunitinib as a single-drug treatment, newer ICI combinations improve overall survival in patients with RCC. Future research on the prevention of adverse events and medication resistance related to newer therapies may aid in ensuring effective treatment outcomes among patients with RCC. This article aims to summarize innovative immunotherapy drug combinations for RCC treatment and the mechanisms of action, drug resistance, and treatment of adverse events associated with these combinations.

Microbiome and lung cancer: carcinogenic mechanisms, early cancer diagnosis, and promising microbial therapies

Microbiomes in the lung, gut, and oral cavity are correlated with lung cancer initiation and progression. While correlations have been preliminarily established in earlier studies, delving into microbe-mediated carcinogenic mechanisms will extend our understanding from correlation to causation. Building upon the causative relationships between microbiome and lung cancer, a novel concept of microbial biomarkers has emerged, mainly encompassing cancer-specific bacteria and circulating microbiome DNA. They might function as noninvasive liquid biopsy techniques for lung cancer early detection. Furthermore, potential microbial therapies have displayed initial efficacy in lung cancer treatment, providing multiple avenues for therapeutic intervention. Herein, we will discuss the molecular mechanisms and signaling pathways through which microbes influence lung cancer initiation and development. Additionally, we will summarize recent findings on microbial biomarkers as a member of tumor liquid biopsy techniques and provide an overview of the latest advances in various microbe-assisted/mediated therapeutic approaches for lung cancer.

Progress in understanding of relationship between intestinal microecology and pancreatic cancer

In recent years, the association between the gut microbiota (GM) and pancreatic cancer (PC) has attracted extensive attention. Studies have shown that the oral, intestinal, and pancreatic microbiota of PC patients is different from that of healthy people, showing different characteristics. On this basis, the application of characteristic GM and its metabolites as biomarkers for early diagnosis and prognosis evaluation of PC holds great potential. Intestinal microecological therapy targeting the GM, such as probiotics and fecal microbiota transplantation, may affect the response to chemotherapy and immunotherapy by remodeling the tumor microenvironment, to improve the prognosis. In this paper, we review the role of the GM in PC development, early diagnosis, prognosis assessment, and treatment.

Cellular and Molecular Mechanisms of the Tumor Stroma in Colorectal Cancer: Insights into Disease Progression and Therapeutic Targets

Colorectal cancer (CRC) is a major health burden worldwide and is the third most common type of cancer. The early detection and diagnosis of CRC is critical to improve patient outcomes. This review explores the intricate interplay between the tumor microenvironment, stromal interactions, and the progression and metastasis of colorectal cancer. The review begins by assessing the gut microbiome's influence on CRC development, emphasizing its association with gut-associated lymphoid tissue (GALT). The role of the Wnt signaling pathway in CRC tumor stroma is scrutinized, elucidating its impact on disease progression. Tumor budding, its effect on tumor stroma, and the implications for patient prognosis are investigated. The review also identifies conserved oncogenic signatures (COS) within CRC stroma and explores their potential as therapeutic targets. Lastly, the seed and soil hypothesis is employed to contextualize metastasis, accentuating the significance of both tumor cells and the surrounding stroma in metastatic propensity. This review highlights the intricate interdependence between CRC cells and their microenvironment, providing valuable insights into prospective therapeutic approaches targeting tumor-stroma interactions.

Molecular Ensembles of Microbiotic Metabolites in Carcinogenesis

The mechanisms of carcinogenesis are extremely complex and involve multiple components that contribute to the malignant cell transformation, tumor growth, and metastasis. In recent decades, there has been a growing interest in the role of symbiotic human microbiota in the regulation of metabolism and functioning of host immune system. The symbiosis between a macroorganism and its microbiota has given rise to the concept of a holoorganism. Interactions between the components of a holoorganism have formed in the process of coevolution, resulting in the acquisition by microbiotic metabolites of a special role of signaling molecules and main regulators of molecular interactions in the holoorganism. As elements of signaling pathways in the host organism, bacterial metabolites have become essential participants in various physiological and pathological processes, including tumor growth. At the same time, signaling metabolites often exhibit multiple effects and impact both the functions of the host cells and metabolic activity and composition of the microbiome. This review discusses the role of microbiotic metabolites in the induction and prevention of malignant transformation of cells in the host organism and their impact on the efficacy of anticancer therapy, with special emphasis on the involvement of some components of the microbial metabolite molecular ensemble in the initiation and progression of tumor growth.

Potential role of gut microbes in the efficacy and toxicity of immune checkpoints inhibitors

In recent years, Immune checkpoint inhibitors have been extensively used in the treatment of a variety of cancers. However, the response rates ranging from 13% to 69% depending on the tumor type and the emergence of immune-related adverse events have posed significant challenges for clinical treatment. As a key environmental factor, gut microbes have a variety of important physiological functions such as regulating intestinal nutrient metabolism, promoting intestinal mucosal renewal, and maintaining intestinal mucosal immune activity. A growing number of studies have revealed that gut microbes further influence the anticancer effects of tumor patients through modulation of the efficacy and toxicity of immune checkpoint inhibitors. Currently, faecal microbiota transplantation (FMT) have been developed relatively mature and suggested as an important regulator in order to enhance the efficacy of treatment. This review is dedicated to exploring the impact of differences in flora composition on the efficacy and toxicity of immune checkpoint inhibitors as well as to summarizing the current progress of FMT.