Modulation of Pulmonary Microbiota by Antibiotic or Probiotic Aerosol Therapy: A Strategy to Promote Immunosurveillance against Lung Metastases

Upregulation of Lactobacillus spp. in gut microbiota as a novel mechanism for environmental eustress-induced anti-pancreatic cancer effects

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with limited effective treatment options. Emerging evidence links enriched environment (EE)-induced eustress to PDAC inhibition. However, the underlying mechanisms remain unclear. In this study, we explored the role of gut microbiota in PDAC-suppressive effects of EE. We demonstrated that depletion of gut microbiota with antibiotics abolished EE-induced tumor suppression, while fecal microbiota transplantation (FMT) from EE mice significantly inhibited tumor growth in both subcutaneous and orthotopic PDAC models housed in standard environment. 16S rRNA sequencing revealed that EE enhanced gut microbiota diversity and selectively enriched probiotic Lactobacillus, particularly L. reuteri. Treatment with L. reuteri significantly suppressed PDAC tumor growth and increased natural killer (NK) cell infiltration into the tumor microenvironment. Depletion of NK cells alleviated the anti-tumor effects of L. reuteri, underscoring the essential role of NK cell-mediated immunity in anti-tumor response. Clinical analysis of PDAC patients showed that higher fecal Lactobacillus abundance correlated with improved progression-free and overall survival, further supporting the therapeutic potential of L. reuteri in PDAC. Overall, this study identifies gut microbiota as a systemic regulator of PDAC under psychological stress. Supplementation of psychobiotic Lactobacillus may offer a novel therapeutic strategy for PDAC.

Tissue-resident microbiota signature in nasopharyngeal carcinoma

BACKGROUND

Emerging evidence reveals that microbiota plays a crucial role in multiple cancers. Nasopharyngeal carcinoma (NPC) tissues harbour microbiota, highlighting the need to investigate the clinical implications of tissue-resident microbiota in the development of NPC. Here, we aim to clarify the specific profile of tissue-resident microbiota and its influence on NPC outcomes.

RESULTS

This retrospective study included 491 NPC patients from Sun Yat-sen University Cancer Center (Guangzhou, China) and the Affiliated Hospital of Guilin Medical College (Guilin, China). We profiled the microbial composition of 343 NPC and 36 normal nasopharyngeal tissues through sequencing of the genes encoding the 16S rRNA subunit of bacterial ribosomes. There were significant differences in microbial composition, alpha diversity (Shannon index, P = 0.007; Simpson index, P = 0.036), and beta diversity (Bray-Curtis distance: R2 = 0.016, F = 5.187, P = 0.001; unweighted UniFrac distance: R2 = 0.017, F = 5.373, P = 0.001) between NPC and normal nasopharyngeal tissues. A bacterial signature comprising four risk bacterial genera, including Bacteroides, Alloprevotella, Parvimonas, and Dialister, was constructed in the training cohort (n = 171). Patients in the high-risk group had shorter disease-free (HR 2.80, 95% CI 1.51-5.18, P < 0.001), distant metastasis-free (HR 4.00, 95% CI 1.77-9.01, P < 0.001), and overall survival (HR 3.45, 95% CI 1.77-6.72, P < 0.001) than those of patients in the low-risk group. Similar results were yielded in the internal validation (n = 172) and external validation (n = 148) cohorts. Integrated multi-omics analysis revealed that NPC tissues harbouring abundant risk bacteria were characterised by deficient immune infiltration, which was verified by multiplex immunohistochemistry.

CONCLUSIONS

This study developed and validated the applicability of a four-bacteria signature as a prognostic tool for NPC prognostication. Integrated multi-omics analysis further uncovered that the tumour immune microenvironment was perturbed by tissue-resident microbiota, which might pave the way towards the era of microbiota-targeted precision medicine for NPC. Video Abstract.

Charting the landscape of intratumoral microbiota in lung cancer: From bench to bedside

The intratumoral microbiota plays a critical role in lung cancer development, metastasis, and treatment response, offering valuable insights into the tumor microenvironment (TME) and revealing new therapeutic opportunities. Lung cancer remains the leading cause of cancer-related deaths worldwide, with the intratumoral microbiota exhibiting unique characteristics and functions within this disease. In this review, we summarized the origin of the intratumoral microbiota, its entry into the tumor, its detailed composition, functions, and its potential clinical applications in lung cancer. For the first time, we estimate the absolute abundance of different microbes in lung cancer, highlight the specific differences in microorganisms, and track their dynamic changes from health to disease. We also describe the overall landscape of intratumoral microbiota. Finally, we discuss the challenges and implications of this emerging field, offering insights for future research and therapeutic strategies.

The Respiratory Tract Microbiome and Human Health

The respiratory tract microbiome (RTM) is a multi-kingdom microbial ecosystem that inhabits various niches of the respiratory system. While previously overlooked, there is now sufficient evidence that the RTM plays a crucial role in human health related to immune system training and protection against pathogens. Accordingly, dysbiosis or disequilibrium of the RTM has been linked to several communicable and non-communicable respiratory diseases, highlighting the need to unveil its role in health and disease. Here, we define the RTM and its place in microbiome medicine. Moreover, we outline the challenges of RTM research, emphasising the need for combining methodologies, including multi-omics and computational tools. We also discuss the RTM's potential for diagnosing, preventing and treating respiratory diseases and developing novel microbiome-based therapies to improve pulmonary health.

Oral and intestinal flora translocation and tumor development

ABSTRACT

Cancer metastasis is the leading cause of death in patients. In recent years, there has been a growing recognition of the role of tumor-associated microflora in tumor metastasis. The connection between oral and gut microflora and the tumor microenvironment has also been extensively studied. The migration of oral and gut microflora is closely associated with tumor development. Although there is awareness regarding the significant impact of microbial communities on human health, the focus on their relationship with host organisms, particularly those related to tumor-associated microflora, remains inadequate. As an integral part of the body, the host microflora is crucial for regulating the cancer risk and preventing tumor recurrence. The oral-gut axis plays an indispensable role in human immunity, and many types of cancers, such as colorectal, pancreatic, and breast, are significantly influenced by their internal microbial communities. However, further exploration into the mechanisms underlying the role of the intratumoral microflora in cancer is necessary to achieve a comprehensive understanding. We have summarized and analyzed related articles in PubMed. This article reviews the impact of the oral-gut axis on the human immune system, explores the relationship between the translocation of the oral and intestinal flora and the tumor microenvironment, analyzes the specific mechanisms involved in the translocation of the oral and intestinal microflora during the evolution and progression of tumors, and elaborates on the correlations between the occurrence and development of tumors and the changes in the microflora. Finally, a summary of these abovementioned points is provided.

The application of organoids in investigating immune evasion in the microenvironment of gastric cancer and screening novel drug candidates

Gastric cancer (GC) is a prevalent digestive system tumor, the fifth most diagnosed cancer worldwide, and a leading cause of cancer deaths. GC is distinguished by its pronounced heterogeneity and a dynamically evolving tumor microenvironment (TME). The lack of accurate disease models complicates the understanding of its mechanisms and impedes the discovery of novel drugs. A growing body of evidence suggests that GC organoids, developed using organoid culture technology, preserve the genetic, phenotypic, and behavioral characteristics. GC organoids hold significant potential for predicting treatment responses in individual patients. This review provides a comprehensive overview of the current clinical treatment strategies for GC, as well as the history, construction and clinical applications of organoids. The focus is on the role of organoids in simulating the TME to explore mechanisms of immune evasion and intratumoral microbiota in GC, as well as their applications in guiding clinical drug therapy and facilitating novel drug screening. Furthermore, we summarize the limitations of GC organoid models and underscore the need for continued technological advancements to benefit both basic and translational oncological research.

From Microbial Ecology to Clinical Challenges: The Respiratory Microbiome's Role in Antibiotic Resistance

Antibiotic resistance represents a growing public health threat, with airborne drug-resistant strains being especially alarming due to their ease of transmission and association with severe respiratory infections. The respiratory microbiome plays a pivotal role in maintaining respiratory health, influencing the dynamics of antibiotic resistance among airborne pathogenic microorganisms. In this context, this review proposes the exploration of the complex interplay between the respiratory microbiota and antimicrobial resistance, highlighting the implications of microbiome diversity in health and disease. Moreover, strategies to mitigate antibiotic resistance, including stewardship programs, alternatives to traditional antibiotics, probiotics, microbiota restoration techniques, and nanotechnology-based therapeutic interventions, are critically presented, setting an updated framework of current management options. Therefore, through a better understanding of respiratory microbiome roles in antibiotic resistance, alongside emerging therapeutic strategies, this paper aims to shed light on how the global health challenges posed by multi-drug-resistant pathogens can be addressed.

Cancer Biology and the Perioperative Period: Opportunities for Disease Evolution and Challenges for Perioperative Care

Efforts to deconvolve the complex interactions of cancer cells with other components of the tumor micro- and macro-environment have exposed a common tendency for cancers to subvert systems physiology and exploit endogenous programs involved in homeostatic control of metabolism, immunity, regeneration, and repair. Many such programs are engaged in the healing response to surgery which, together with other abrupt biochemical changes in the perioperative period, provide an opportunity for the macroevolution of residual disease. This review relates contemporary perspectives of cancer as a systemic disease with the overlapping biology of host responses to surgery and events within the perioperative period. With a particular focus on examples of cancer cell plasticity and changes within the host, we explore how perioperative inflammation and acute metabolic, neuroendocrine, and immune dyshomeostasis might contribute to cancer evolution within this contextually short, yet crucially influential timeframe, and highlight potential therapeutic opportunities within to further optimize surgical cancer care and its long-term oncological outcomes.

Landscape of the intratumoral microbiota acting on the tumor immune microenvironment in LUAD and LUSC

Although the intratumoral microbiota has been discovered to have a close connection with tumor immunity, the specific role played by intratumoral microbiota in regulating the tumor immune microenvironment (TIME) of lung cancer remains largely unexplored. Here, we comprehensively investigated the association between intratumoral microbiota and the TIME in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC). First, we found that intratumoral microbiota and host transcriptome profile significantly differed between LUAD and LUSC. Moreover, there were strong associations between the abundance of intratumoral microbes and the expression of host genes in both LUAD and LUSC. Furthermore, we found an association between intratumoral Lachnoclostridium and chemokine expression, suggesting a role for these species of microbiota in modulating tumor immunity. In addition, we found that tumors harbor distinct relative abundance of Lachnoclostridium presented variation in response to immunotherapy and sensitivity to potential drug candidates. Our study provided important insights into the regulation of intratumoral microbiota on the TIME in LUAD and LUSC, which may serve as a precursor for a hypothesis-driven study to better understand the causational relationship of intratumoral microbiota in lung cancer.NEW & NOTEWORTHY LUAD and LUSC exhibited significant differences in intratumoral microbiome and the TIME profile. The relative abundance of intratumoral Lachnoclostridium correlated with the tumor immune infiltration in both LUSC and LUAD. Intratumoral Lachnoclostridium impacted the patients' sensitivity to potential targeted drugs, especially in LUSC.

Unveiling the microbial influence: bacteria's dual role in tumor metastasis

As cancer research advances, the intricate relationship between the microbiome and cancer is gaining heightened recognition, especially concerning tumor metastasis, where bacterial involvement becomes increasingly complex. This review seeks to systematically examine the dual roles of bacteria in the tumor metastasis process, encompassing both mechanisms that facilitate metastasis and the inhibitory effects exerted by specific microorganisms. We explore the mechanisms through which bacteria influence tumor cell migration by inducing chronic inflammation, evading host immune responses, and remodeling the ECM. Moreover, the immunomodulatory potential of probiotics and genetically engineered bacteria offers promising prospects for the prevention and treatment of tumor metastasis. This article elucidates the complexity and emerging frontiers of bacterial involvement in tumor metastasis by examining the clinical significance of bacteria as potential biomarkers and evaluating the effects of antibiotic usage on the metastatic process. We posit that comprehending the biological characteristics and clinical significance of bacteria, as a critical component of the tumor microenvironment, will offer innovative strategies and theoretical foundations for cancer treatment. Furthermore, this article explores future research directions, including the application of microbiome technologies and bacteria-based therapeutic strategies, thereby offering a valuable perspective for the development of novel anti-cancer approaches.

Research status of the relationship between microecological imbalance and lung cancer

Microecology refers to the ecosystem formed by human and microbial communities in the process of co-evolution, the microecological imbalance is associated with occurrence and development of multiple diseases, including lung cancer. In this review, we detailedly summarized the concept and roles of microecology, the relationship between microecology and human diseases, and related techniques in microecology studies. Importantly, we specially analyzed the correlations between microecology and lung cancer by focusing on gut microbiota, oral microbiota and lower respiratory tract microbiota, and further evaluated the effects of microbiota dysbiosis on chemotherapy and immunotherapy efficacy in lung cancer. At last, we discussed the potential mechanisms by which dysregulated microbiota promotes the genesis and development of lung cancer. Microecology-centered detection and intervention will improve the early diagnosis of lung cancer and provide new targets for the treatment of lung cancer.

Implications of intratumoral microbiota in tumor metastasis: a special perspective of microorganisms in tumorigenesis and clinical therapeutics

Tumor metastasis is the main cause of therapeutic failure and mortality in cancer patients. The intricate metastastic process is influenced by both the intrinsic properties of tumor cells and extrinsic factors, such as microorganisms. Notably, some microbiota have been discovered to colonize tumor tissues, collectively known as intratumoral microbiota. Intratumoral microbiota can modulate tumor progression through multiple mechanisms, including regulating immune responses, inducing genomic instability and gene mutations, altering metabolic pathways, controlling epigenetic pathways, and disrupting cancer-related signaling pathways. Furthermore, intratumoral microbiota have been shown to directly impact tumor metastasis by regulating cell adhesion, stem cell plasticity and stemness, mechanical stresses and the epithelial-mesenchymal transition. Indirectly, they may affect tumor metastasis by modulating the host immune system and the tumor microenvironment. These recent findings have reshaped our understanding of the relationship between microorganims and the metastatic process. In this review, we comprehensively summarize the existing knowledge on tumor metastasis and elaborate on the properties, origins and carcinogenic mechanisms of intratumoral microbiota. Moreover, we explore the roles of intratumoral microbiota in tumor metastasis and discuss their clinical implications. Ongoing research in this field will establish a solid foundation for novel therapeutic strategies and clinical treatments for various tumors.

Tumor microbiome: roles in tumor initiation, progression, and therapy

Over the past few years, the tumor microbiome is increasingly recognized for its multifaceted involvement in cancer initiation, progression, and metastasis. With the application of 16S ribosomal ribonucleic acid (16S rRNA) sequencing, the intratumoral microbiome, also referred to as tumor-intrinsic or tumor-resident microbiome, has also been found to play a significant role in the tumor microenvironment (TME). Understanding their complex functions is critical for identifying new therapeutic avenues and improving treatment outcomes. This review first summarizes the origins and composition of these microbial communities, emphasizing their adapted diversity across a diverse range of tumor types and stages. Moreover, we outline the general mechanisms by which specific microbes induce tumor initiation, including the activation of carcinogenic pathways, deoxyribonucleic acid (DNA) damage, epigenetic modifications, and chronic inflammation. We further propose the tumor microbiome may evade immunity and promote angiogenesis to support tumor progression, while uncovering specific microbial influences on each step of the metastatic cascade, such as invasion, circulation, and seeding in secondary sites. Additionally, tumor microbiome is closely associated with drug resistance and influences therapeutic efficacy by modulating immune responses, drug metabolism, and apoptotic pathways. Furthermore, we explore innovative microbe-based therapeutic strategies, such as engineered bacteria, oncolytic virotherapy, and other modalities aimed at enhancing immunotherapeutic efficacy, paving the way for microbiome-centered cancer treatment frameworks.

The implication of microbiome in lungs cancer: mechanisms and strategies of cancer growth, diagnosis and therapy

Available evidence illustrates that microbiome is a promising target for the study of growth, diagnosis and therapy of various types of cancer. Lung cancer is a leading cause of cancer death worldwide. The relationship of microbiota and their products with diverse pathologic conditions has been getting large attention. The novel research suggests that the microbiome plays an important role in the growth and progression of lung cancer. The lung microbiome plays a crucial role in maintaining mucosal immunity and synchronizing the stability between tolerance and inflammation. Alteration in microbiome is identified as a critical player in the progression of lung cancer and negatively impacts the patient. Studies suggest that healthy microbiome is essential for effective therapy. Various clinical trials and research are focusing on enhancing the treatment efficacy by altering the microbiome. The regulation of microbiota will provide innovative and promising treatment strategies for the maintenance of host homeostasis and the prevention of lung cancer in lung cancer patients. In the current review article, we presented the latest progress about the involvement of microbiome in the growth and diagnosis of lung cancer. Furthermore, we also assessed the therapeutic status of the microbiome for the management and treatment of lung cancer.

A Perspective on Lung Cancer and Lung Microbiome: Insight on Immunity

BACKGROUND

Although the carcinogenic potential of microbes has long been recognized, their significance may have been underestimated. Currently, the connection between microbiota and cancer is under extensive research. The lung microbiota may serve as a proxy for the state of lung health based on its crucial role in preserving lung hemostasis.

OBJECTIVES

This review tried to outline the state of our understanding of the contribution of lung microbiome and lung cancer.

METHODS

A literature search was performed using PubMed, Google Scholar, and Scopus databases for recent research focusing on the development and possible pathogenesis of lung microbiome and lung cancer.

RESULTS

Early research on lung cancer indicated that dysbiosis significantly impacted the development and spread of the tumor. As a result of these findings, the study of the lung microbiota as a possible therapeutic target and diagnostic marker has accelerated. Early-stage disease diagnostic biomarkers could be represented as microbiota profiles. Additionally, the microbiome is involved in anticancer therapy. There are limited studies on lung microbiota, and most microbiome studies commonly concentrate on the gut microbiota. A proper understanding of lung microbiota can have several potential therapeutic approaches. Therefore, more studies in this field may initiate remarkable advancements in microbiome-dependent treatment.

CONCLUSION

Convincing data from studies on both humans and animals indicates that the microbiota might play a role in cancer initiation, influenced by internal and environmental factors of the host. Notably, the lung harbors its microbiome, as do lung cancers. In general view, it seems microbiome diversity in lung cancer patients is reduced. Meanwhile, some genera were increased in lung cancer patients in comparison with a noncancerous population (such as Streptococcus genus), and some of them were decreased (Granulicatella adiacens, G. adiacens). Furthermore, research on the microbiome-carcinogenesis relationship is still in its infancy, and much remains to be fully understood.

Lower respiratory tract microbiome dysbiosis impairs clinical responses to immune checkpoint blockade in advanced non-small-cell lung cancer

BACKGROUND

Gut microbiome on predicting clinical responses to immune checkpoint inhibitors (ICIs) has been discussed in detail for decades, while microecological features of the lower respiratory tract within advanced non-small-cell lung cancer (NSCLC) are still relatively vague.

METHODS

During this study, 26 bronchoalveolar lavage fluids (BALF) from advanced NSCLC participants who received immune checkpoint inhibitor monotherapy were performed 16S rRNA sequencing and untargeted metabolome sequencing to identify differentially abundant microbes and metabolic characteristics. Additionally, inflammatory cytokines and chemokines were also launched in paired BALF and serum samples by immunoassays to uncover their underlying correlations. The omics data were separately analyzed and integrated by using multiple correlation coefficients. Multiplex immunohistochemical staining was then used to assess the immune cell infiltration after immune checkpoint blockade therapy.

RESULTS

Lower respiratory tract microbiome diversity favoured preferred responses to ICIs. Microbial markers demonstrated microbial diversity overweight a single strain in favoured response to ICI therapy, where Bacillus matters. Sphingomonas and Sediminibacterium were liable to remodulate lipid and essential amino acid degradations to embrace progression after immunotherapies. Microbiome-derived metabolites reshaped the immune microenvironment in the lower respiratory tract by releasing inflammatory cytokines and chemokines, which was partially achieved by metabolite-mediated tumoral inflammatory products and reduction of CD8+ effective T cells and M1 phenotypes macrophages in malignant lesions.

CONCLUSIONS

This study provided a microecological landscape of the lower respiratory tract with advanced NSCLC to ICI interventions and presented a multidimensional perspective with favoured outcomes that may improve the predictive capacity of the localized microbiome in clinical practices.

HIGHLIGHTS

Alterations of the lower respiratory tract microbiome indicate different clinical responses to ICB within advanced NSCLC. Reduced microbial diversity of lower respiratory tracts impairs anti-tumoral performances. Microbe-derived metabolites perform as a dominant regulator to remodify the microecological environment in lower respiratory tracts. Multi-omics sequencings of the lower respiratory tract possess the potential to predict the long-term clinical responses to ICB among advanced NSCLC.

The Gut Microbiome and Its Multifaceted Role in Cancer Metabolism, Initiation, and Progression: Insights and Therapeutic Implications

This review summarizes the intricate relationship between the microbiome and cancer initiation and development. Microbiome alterations impact metabolic pathways, immune responses, and gene expression, which can accelerate or mitigate cancer progression. We examine how dysbiosis affects tumor growth, metastasis, and treatment resistance. Additionally, we discuss the potential of microbiome-targeted therapies, such as probiotics and fecal microbiota transplants, to modulate cancer metabolism. These interventions offer the possibility of reversing or controlling cancer progression, enhancing the efficacy of traditional treatments like chemotherapy and immunotherapy. Despite promising developments, challenges remain in identifying key microbial species and pathways and validating microbiome-targeted therapies through large-scale clinical trials. Nonetheless, the intersection of microbiome research and cancer initiation and development presents an exciting frontier for innovative therapies. This review offers a fresh perspective on cancer initiation and development by integrating microbiome insights, highlighting the potential for interdisciplinary research to enhance our understanding of cancer progression and treatment strategies.

Unravelling the prognostic and operative role of intratumoural microbiota in non-small cell lung cancer: Insights from 16S rRNA and RNA sequencing

BACKGROUND

Complex interrelationships between the microbiota and cancer have been identified by several studies. However, despite delineating microbial composition in non-small cell lung cancer (NSCLC), key pathogenic microbiota and their underlying mechanisms remain unclear.

METHODS

We performed 16S rRNA V3-V4 amplicon and transcriptome sequencing on cancerous and adjacent normal tissue samples from 30 patients with NSCLC, from which clinical characteristics and prognosis outcomes were collected. We used 16S rRNA sequencing to dissect microbial composition and perform prognosis correlations, and in conjunction with transcriptome sequencing, we determined potential mechanisms underpinning significant microbiota actions.

RESULTS

In comparing different sample types, we identified more pronounced beta diversity disparity between NSCLC, lung squamous cell carcinoma (LUSC) and corresponding paired normal tissues. Concurrently, LUSC and lung adenocarcinoma exhibited distinct microbial composition traits at genus levels. Subsequently, four phyla, five classes, nine orders, 17 families and 36 genera were filtered out and were related to prognosis outcomes. Intriguingly, a protective microbial cluster was identified encompassing nine genera associated with delayed disease recurrence, with functional analyses suggested that these microbiota predominantly exerted metabolism-related functions. Additionally, a harmful microbial cluster (HMC) was identified, including three genera. In this HMC and subsequent prognosis model analyses, harmful intratumoural microbiota were potentially implicated in infection, inflammation and immune regulation. Crucially, we identified a microbial genus, Peptococcus, which was as an independent, detrimental NSCLC prognostic factor and potentially impacted prognosis outcomes via tumour necrosis factor (TNF) signalling.

CONCLUSIONS

We identified a substantial connection between intratumoural microbiota and NSCLC prognosis outcomes. Protective microbiota primarily exerted metabolic functions, whereas harmful microbiota were mainly implicated in infection, inflammation and immune modulation. Furthermore, Peptococcus may be significant in adverse NSCLC prognoses and serve as a potential biomarker for patient management and cancer screening.

KEY POINTS

Four phyla, five classes, nine orders, 17 families and 36 genera have been found associated with NSCLC prognosis. We identified a protective microbial cluster associated with delayed recurrence and a harmful microbial cluster related to shorter survival and earlier recurrence. We identified Peptococcus as an independent, detrimental prognostic factor for NSCLC, potentially impacting prognosis via TNF signalling.

A visualization analysis of immune-related adverse reactions in pulmonary carcinoma

Immunotherapy has emerged as a crucial advancement in pulmonary carcinoma treatment. Nevertheless, its unique side effects not only reduce patients' quality of life but also affect treatment efficacy, with severe cases potentially endangering the patient's life. This study uses bibliometric analysis to perform a comprehensive bibliometric analysis literature on IRAEs in lung cancer from 1991 to 2023, retrieved from the Web of Science database. The dataset was analyzed using VOSviewer and CiteSpace to identify trends, key contributors, and emerging research areas. A total of 124 publications were analyzed, revealing a notable increase in research activity post-2015, with China and the USA contributing over 50% of the studies. This research highlights the importance of understanding IRAEs and suggests future investigations into the pulmonary microbiota and tumor microenvironment.

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.

New Relevant Evidence in Cholangiocarcinoma Biology and Characterization

Among solid tumors, cholangiocarcinoma (CCA) emerges as one of the most difficult to eradicate. The silent and asymptomatic nature of this tumor, particularly in its early stages, as well as the high heterogeneity at genomic, epigenetic, and molecular levels delay the diagnosis, significantly compromising the efficacy of current therapeutic options and thus contributing to a dismal prognosis. Extensive research has been conducted on the molecular pathobiology of CCA, and recent advances have been made in the classification and characterization of new molecular targets. Both targeted therapy and immunotherapy have emerged as effective and safe strategies for various types of cancers, demonstrating potential benefits in advanced CCA. Furthermore, the deeper comprehension of the cellular and molecular components in the tumor microenvironment (TME) has opened up possibilities for new innovative treatment methods. This review discusses recent evidence in the characterization and molecular biology of CCA, highlighting novel possible druggable targets.

C-Reactive Protein Induces Immunosuppression by Activating FcγR2B in Pulmonary Macrophages to Promote Lung Metastasis

C-reactive protein (CRP) is a liver-derived acute phase reactant that is a clinical marker of inflammation associated with poor cancer prognosis. Elevated CRP levels are observed in many types of cancer and are associated with significantly increased risk of metastasis, suggesting that CRP could have prometastatic actions. In this study, we reported that CRP promotes lung metastasis by dampening the anticancer capacity of pulmonary macrophages in breast cancer and melanoma. Deletion of CRP in mice inhibited lung metastasis of breast cancer and melanoma cells without significantly impacting tumor growth compared with wild-type mice. In addition, the lungs of CRP-deficient mice were enriched for activated pulmonary macrophages, which could be reduced to the level of wild-type mice by systemic administration of human CRP. Mechanistically, CRP blocked the activation of pulmonary macrophages induced by commensal bacteria in a FcγR2B-dependent manner, thereby impairing macrophage-mediated immune surveillance to promote the formation of a premetastatic niche in the lungs of tumor-bearing mice. Accordingly, treatment with specific CRP inhibitors activated pulmonary macrophages and attenuated lung metastasis in vivo. These findings highlight the importance of CRP in lung metastasis, which may represent an effective therapeutic target for patients with advanced solid cancers in clinics. Significance: CRP maintains host-commensal tolerance by inhibiting pulmonary macrophage activation and can be targeted to remodel the premetastatic niche in the lung to lower the risk of cancer metastasis. See related commentary by Saal et al., p. 4121.

Inhalation exposure to chemicals, microbiota dysbiosis and adverse effects on humans

As revealed by culture-independent methodologies, disruption of the normal lung microbiota (LM) configuration (LM dysbiosis) is a potential mediator of adverse effects from inhaled chemicals. LM, which consists of microbiota in the upper and lower respiratory tract, is influenced by various factors, including inter alia environmental exposures. LM dysbiosis has been associated with multiple respiratory pathologies such as asthma, lung cancer, idiopathic pulmonary fibrosis (IPF), chronic obstructive pulmonary disease (COPD) and cystic fibrosis (CF). Chemically-induced LM dysbiosis appears to play significant roles in human respiratory diseases, as has been shown for some air pollutants, cigarette smoke and some inhalable chemical antibiotics. Lung microbiota are also linked with the central nervous system (CNS) in the so-called lung-brain axis. Inhaled chemicals that undergo mucociliary clearance may be linked to respiratory conditions through gut microbiota (GM) dysbiosis in the so-called Gut-Lung axis. However, current linkages of various disease states to LM appears to be associative, with causal linkages requiring further studies using more robust approaches, methods and techniques that are different from those applied in studies involving (GM). Most importantly, the sampling techniques determine the level of risk of cross contamination. Furthermore, the development of continuous or semi-continuous systems designed to replicate the lung microbiome will go a long way to further LM dysbiosis studies. These challenges notwithstanding, the preponderance of evidence points to the significant role of LM-mediated chemical toxicity in human disease and conditions.

Concurrent ozone and high temperature exacerbates nasal epithelial barrier damage in allergic rhinitis mice: Insights from the nasal transcriptome and nasal microbiota

The global ambient temperature has been rising in recent decades and high temperature is usually accompanied by ozone (O3) pollution. Environmental change is an underlying factor for the increased prevalence of respiratory allergic disease. However, the potential mechanisms are complex and remain elusive. This study was performed to reveal toxic effects and molecular mechanisms of O3 or/and high temperature induced allergic rhinitis (AR) deterioration. The results indicated that O3 and high temperature co-exposure exacerbated rhinitis symptoms, destroyed ultrastructure of nasal mucosa and down-regulated the expression of nasal epithelial barrier structural proteins ZO-1 and occludin. Moreover, the levels of total protein and lactate dehydrogenase (LDH) in nasal lavage fluid and the levels of IL-1β and TNF-α in serum also exhibited a significant upward trend. Transcriptomic analysis revealed that immune and inflammatory signaling pathways such as IL-17 signaling pathway was involved in the combined toxicity of O3 and high temperature. Microbiome examination showed that Prevotella and Elizabethkingia were linked to nasal injury. What's more, spearman correlation analysis revealed correlations among nasal microbiota dysbiosis, inflammation and injury. To sum up, the present study assessed the combined toxicity of O3 and high temperature and found potential mechanisms, which provided important experimental evidence for making preventive intervention strategies and protecting vulnerable populations.

Identifications of the potential in-silico biomarkers in lung cancer tissue microbiomes

It is postulated that the tumor tissue microbiome is one of the enabling characteristics that can either promote or suppress the ability of tumors to acquire certain hallmarks of cancer. This underscores its critical importance in carcinogenesis, cancer progression, and therapy responses. However, characterizing the tumor microbiomes is extremely challenging because of their low biomass and severe difficulties in controlling laboratory-borne contaminants, which is further aggravated by lack of comprehensively effective computational approaches to identify unique or enriched microbial species associated with cancers. Here we take advantage of a recent computational framework by Ma (2024), termed metagenome comparison (MC) framework (MCF), which can detect treatment-specific, unique or enriched OMUs (operational metagenomic unit), or US/ES (unique/enriched species) when adapted for this study. We apply the MCF to reanalyze four lung cancer tissue microbiome datasets, which include samples from Lung Adenocarcinoma (LUAD), Lung Squamous Cell Carcinoma (LUSC), and their adjacent normal tissue (NT) controls. Our analysis is structured around three distinct schemes: Scheme I-separately detecting the US/ES for each of the four lung cancer microbiome datasets; Scheme II-consolidation of the four datasets followed by detection of US/ES in the combined datasets; Scheme III-construction of the union and intersection sets of US/ES derived from the results of the preceding two schemes. The generated lists of US/ES, including enriched microbial phyla, likely hold significant biomedical value for developing diagnostic and prognostic biomarkers for lung cancer risk assessment, improving the efficacy of immunotherapy, and designing novel microbiome-based therapies in lung cancer research.

Beyond Tumor Borders: Intratumoral Microbiome Effects on Tumor Behavior and Therapeutic Responses

The human body contains a diverse array of microorganisms, which exert a significant impact on various physiological processes, including immunity, and can significantly influence susceptibility to various diseases such as cancer. Recent advancements in metagenomic sequencing have uncovered the role of intratumoral microbiome, which covertly altered the development of cancer, the growth of tumors, and the response to existing treatments through multiple mechanisms. These mechanisms involve mainly DNA damage induction, oncogenic signaling pathway activation, and the host's immune response modulation. To explore novel therapeutic options and effectively target and regulate the intratumoral microbiome, a comprehensive understanding of these processes is indispensable. Here, we will explore various potential actions of the intratumoral microbiome concerning the initiation and progression of tumors. We will examine its impact on responses to chemotherapy, radiotherapy, and immunotherapy. Additionally, we will discuss the current state of knowledge regarding the use of genetically modified bacteria as a promising treatment option for cancer.

Influence of gut and lung dysbiosis on lung cancer progression and their modulation as promising therapeutic targets: a comprehensive review

Lung cancer (LC) continues to pose the highest mortality and exhibits a common prevalence among all types of cancer. The genetic interaction between human eukaryotes and microbial cells plays a vital role in orchestrating every physiological activity of the host. The dynamic crosstalk between gut and lung microbiomes and the gut-lung axis communication network has been widely accepted as promising factors influencing LC progression. The advent of the 16s rDNA sequencing technique has opened new horizons for elucidating the lung microbiome and its potential pathophysiological role in LC and other infectious lung diseases using a molecular approach. Numerous studies have reported the direct involvement of the host microbiome in lung tumorigenesis processes and their impact on current treatment strategies such as radiotherapy, chemotherapy, or immunotherapy. The genetic and metabolomic cross-interaction, microbiome-dependent host immune modulation, and the close association between microbiota composition and treatment outcomes strongly suggest that designing microbiome-based treatment strategies and investigating new molecules targeting the common holobiome could offer potential alternatives to develop effective therapeutic principles for LC treatment. This review aims to highlight the interaction between the host and microbiome in LC progression and the possibility of manipulating altered microbiome ecology as therapeutic targets.

Bacterial live therapeutics for human diseases

The genomic revolution has fueled rapid progress in synthetic and systems biology, opening up new possibilities for using live biotherapeutic products (LBP) to treat, attenuate or prevent human diseases. Among LBP, bacteria-based therapies are particularly promising due to their ability to colonize diverse human tissues, modulate the immune system and secrete or deliver complex biological products. These bacterial LBP include engineered pathogenic species designed to target specific diseases, and microbiota species that promote microbial balance and immune system homeostasis, either through local administration or the gut-body axes. This review focuses on recent advancements in preclinical and clinical trials of bacteria-based LBP, highlighting both on-site and long-reaching strategies.

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

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

Bacteria and fungi of the lung: allies or enemies?

Moving from the earlier periods in which the lungs were believed to represent sterile environments, our knowledge on the lung microbiota has dramatically increased, from the first descriptions of the microbial communities inhabiting the healthy lungs and the definition of the ecological rules that regulate its composition, to the identification of the changes that occur in pathological conditions. Despite the limitations of lung as a microbiome reservoir due to the low microbial biomass and abundance, defining its microbial composition and function in the upper and lower airways may help understanding the impact on local homeostasis and its disruption in lung diseases. In particular, the understanding of the metabolic and immune significance of microbes, their presence or lack thereof, in health and disease states could be valuable in development of novel druggable targets in disease treatments. Next-generation sequencing has identified intricate inter-microbe association networks that comprise true mutualistic or antagonistic direct or indirect relationships in the respiratory tract. In this review, the tripartite interaction of bacteria, fungi and the mammalian host is addressed to provide an integrated view of the microbial-host cross-talk in lung health and diseases from an immune and metabolic perspective.

Beyond the Gut: The intratumoral microbiome's influence on tumorigenesis and treatment response

The intratumoral microbiome (TM) refers to the microorganisms in the tumor tissues, including bacteria, fungi, viruses, and so on, and is distinct from the gut microbiome and circulating microbiota. TM is strongly associated with tumorigenesis, progression, metastasis, and response to therapy. This paper highlights the current status of TM. Tract sources, adjacent normal tissue, circulatory system, and concomitant tumor co-metastasis are the main origin of TM. The advanced techniques in TM analysis are comprehensively summarized. Besides, TM is involved in tumor progression through several mechanisms, including DNA damage, activation of oncogenic signaling pathways (phosphoinositide 3-kinase [PI3K], signal transducer and activator of transcription [STAT], WNT/β-catenin, and extracellular regulated protein kinases [ERK]), influence of cytokines and induce inflammatory responses, and interaction with the tumor microenvironment (anti-tumor immunity, pro-tumor immunity, and microbial-derived metabolites). Moreover, promising directions of TM in tumor therapy include immunotherapy, chemotherapy, radiotherapy, the application of probiotics/prebiotics/synbiotics, fecal microbiome transplantation, engineered microbiota, phage therapy, and oncolytic virus therapy. The inherent challenges of clinical application are also summarized. This review provides a comprehensive landscape for analyzing TM, especially the TM-related mechanisms and TM-based treatment in cancer.

Pathogenic mechanisms and latest therapeutic approaches for radiation-induced lung injury: A narrative review

The treatment of thoracic tumors with ionizing radiation can cause radiation-induced lung injury (RILI), which includes radiation pneumonitis and radiation-induced pulmonary fibrosis. Preventing RILI is crucial for controlling tumor growth and improving quality of life. However, the serious adverse effects of traditional RILI treatment methods remain a major obstacle, necessitating the development of novel treatment options that are both safe and effective. This review summarizes the molecular mechanisms of RILI and explores novel treatment options, including natural compounds, gene therapy, nanomaterials, and mesenchymal stem cells. These recent experimental approaches show potential as effective prevention and treatment options for RILI in clinical practice.

Role of respiratory system microbiota in development of lung cancer and clinical application

Microbes play a significant role in human tumor development and profoundly impact treatment efficacy, particularly in immunotherapy. The respiratory tract extensively interacts with the external environment and possesses a mucosal immune system. This prompts consideration of the relationship between respiratory microbiota and lung cancer. Advancements in culture-independent techniques have revealed unique communities within the lower respiratory tract. Here, we provide an overview of the respiratory microbiota composition, dysbiosis characteristics in lung cancer patients, and microbiota profiles within lung cancer. We delve into how the lung microbiota contributes to lung cancer onset and progression through direct functions, sustained immune activation, and immunosuppressive mechanisms. Furthermore, we emphasize the clinical utility of respiratory microbiota in prognosis and treatment optimization for lung cancer.

Intratumoral Escherichia Is Associated With Improved Survival to Single-Agent Immune Checkpoint Inhibition in Patients With Advanced Non-Small-Cell Lung Cancer

PURPOSEThe impact of the intratumoral microbiome on immune checkpoint inhibitor (ICI) efficacy in patients with non-small-cell lung cancer (NSCLC) is unknown. Preclinically, intratumoral Escherichia is associated with a proinflammatory tumor microenvironment and decreased metastases. We sought to determine whether intratumoral Escherichia is associated with outcome to ICI in patients with NSCLC.PATIENTS AND METHODSWe examined the intratumoral microbiome in 958 patients with advanced NSCLC treated with ICI by querying unmapped next-generation sequencing reads against a bacterial genome database. Putative environmental contaminants were filtered using no-template controls (n = 2,378). The impact of intratumoral Escherichia detection on overall survival (OS) was assessed using univariable and multivariable analyses. The findings were further validated in an external independent cohort of 772 patients. Escherichia fluorescence in situ hybridization (FISH) and transcriptomic profiling were performed.RESULTSIn the discovery cohort, read mapping to intratumoral Escherichia was associated with significantly longer OS (16 v 11 months; hazard ratio, 0.73 [95% CI, 0.59 to 0.92]; P = .0065) in patients treated with single-agent ICI, but not combination chemoimmunotherapy. The association with OS in the single-agent ICI cohort remained statistically significant in multivariable analysis adjusting for prognostic features including PD-L1 expression (P = .023). Analysis of an external validation cohort confirmed the association with improved OS in univariable and multivariable analyses of patients treated with single-agent ICI, and not in patients treated with chemoimmunotherapy. Escherichia localization within tumor cells was supported by coregistration of FISH staining and serial hematoxylin and eosin sections. Transcriptomic analysis correlated Escherichia-positive samples with expression signatures of immune cell infiltration.CONCLUSIONRead mapping to potential intratumoral Escherichia was associated with survival to single-agent ICI in two independent cohorts of patients with NSCLC.

Ethnic foods: impact of probiotics on human health and disease treatment

The human gut is inhabited by approximately 100 trillion of microflora, and there exists a reciprocal relationship between human health and the gut microbiota. The major reasons for the dysbiosis in the population of gut microbiota are attributed to changes in lifestyle, medication, and the intake of junk foods. In addition, the proportion of beneficial bacteria in the intestine decreases gradually with age and causes physiological disturbances, malfunctions of the immune system, and several metabolic disorders. Thus, finding safe solutions to improve the diversity of microflora is a big challenge. With an increase in health consciousness among the population, the demand for healthy and nutraceutical food products is growing gradually. Recent research has proved that consumption of probiotics promotes gut health and prevents from several metabolic and other diseases. Hence, in this present review, we will discuss the various probiotic bacteria present in ethnic foods. The importance of these probiotics in the prevention and treatment of gastrointestinal, respiratory, cancer, and metabolic disorders will be elucidated. In addition, we will highlight the importance of the development of new-generation probiotics to cater the needs of the current market.

Aldehyde-based Activation of C2α-lactylthiamin Diphosphate Decarboxylation on Bacterial 1-deoxy-d-xylulose 5-phosphate Synthase

1-Deoxy-d-xylulose 5-phosphate synthase (DXPS) catalyzes the thiamin diphosphate (ThDP)-dependent formation of DXP from pyruvate (donor substrate) and d-glyceraldehyde 3-phosphate (d-GAP, acceptor substrate) in bacterial central metabolism. DXPS uses a ligand-gated mechanism in which binding of a small molecule "trigger" activates the first enzyme-bound intermediate, C2α-lactylThDP (LThDP), to form the reactive carbanion via LThDP decarboxylation. d-GAP is the natural acceptor substrate for DXPS and also serves a role as a trigger to induce LThDP decarboxylation in the gated step. Additionally, we have shown that O2 and d-glyceraldehyde (d-GA) can induce LThDP decarboxylation. We hypothesize this ligand-gated mechanism poises DXPS to sense and respond to cellular cues in metabolic remodeling during bacterial adaptation. Here we sought to characterize features of small molecule inducers of LThDP decarboxylation. Using a combination of CD, NMR and biochemical methods, we demonstrate that the α-hydroxy aldehyde moiety of d-GAP is sufficient to induce LThDP decarboxylation en route to DXP formation. A variety of aliphatic aldehydes also induce LThDP decarboxylation. The study highlights the capacity of DXPS to respond to different molecular cues, lending support to potential multifunctionality of DXPS and its metabolic regulation by this mechanism.

Anti-tuberculosis effect of microbiome therapeutic PMC205 in extensively drug-resistant pulmonary tuberculosis in vivo

BACKGROUND

Tuberculosis is a highly contagious disease caused by Mycobacterium tuberculosis, and the increase in antibiotic resistance threatens humankind. Therefore, there is an urgent need to develop new anti-tuberculosis drugs that can overcome the limitations of existing drugs. Here, we report the anti-tuberculosis effect of microbiome therapeutic PMC205, a strain of Bacillus subtilis.

METHODS

The anti-tuberculosis activity of probiotics was evaluated in mouse models of lethal and latent pulmonary tuberculosis induced by high or low-dose infection of the extensively drug-resistant strain. Probiotics were administered by inhalation, and the burden of M. tuberculosis in the lungs, along with mortality and clinical observations, were monitored for 12 weeks and 8 months, respectively. For an in-depth understanding, analysis of the microbiome and inflammatory profile of the lung microenvironment and induction of autophagy in vitro were explored.

RESULTS

After inhalation administration of PMC205 for 3 months, the survival rate was 100%, unlike all deaths in the saline-treated group, and the burden of M. tuberculosis in the lungs was reduced by log 1.3 in the 8-month latent tuberculosis model. Moreover, PMC205 induced recovery of disrupted lung microflora, increased butyric acid, and suppressed excessive inflammation. It also promoted autophagy.

CONCLUSIONS

These results confirm PMC205's anti-tuberculosis effect, suggesting that it can be developed as an adjuvant to current antibiotic therapy to solve the drug-resistant tuberculosis problem.

Engineered probiotic Escherichia coli elicits immediate and long-term protection against influenza A virus in mice

Influenza virus infection remains a major global health problem and requires a universal vaccine with broad protection against different subtypes as well as a rapid-response vaccine to provide immediate protection in the event of an epidemic outbreak. Here, we show that intranasal administration of probiotic Escherichia coli Nissle 1917 activates innate immunity in the respiratory tract and provides immediate protection against influenza virus infection within 1 day. Based on this vehicle, a recombinant strain is engineered to express and secret five tandem repeats of the extracellular domain of matrix protein 2 from different influenza virus subtypes. Intranasal vaccination with this strain induces durable humoral and mucosal responses in the respiratory tract, and provides broad protection against the lethal challenge of divergent influenza viruses in female BALB/c mice. Our findings highlight a promising delivery platform for developing mucosal vaccines that provide immediate and sustained protection against respiratory pathogens.

Modulating the gut microbiome in non-small cell lung cancer: Challenges and opportunities

Despite the efficacy of immunotherapy in non-small cell lung cancer (NSCLC), the majority of the patients experience relapse with limited subsequent treatment options. Preclinical studies of various epithelial tumors, such as melanoma and NSCLC, have shown that harnessing the gut microbiome resulted in improvement of therapeutic responses to immunotherapy. Is this review, we summarize the role of microbiome, including lung and gut microbiome in the context of NSCLC, provide overview of the mechanisms of microbiome in efficacy and toxicity of chemotherapies and immunotherapies, and address current ongoing clinical trials for NSCLC including fecal microbiota transplantation (FMT) and live biotherapeutic products (LBPs).

Microbes in the tumor microenvironment: New additions to break the tumor immunotherapy dilemma

Immunotherapies currently used in clinical practice are unsatisfactory in terms of therapeutic response and toxic side effects, and therefore new immunotherapies need to be explored. Intratumoral microbiota (ITM) exists in the tumor environment (TME) and reacts with its components. On the one hand, ITM promotes antigen delivery to tumor cells or provides cross-antigens to promote immune cells to attack tumors. On the other hand, ITM affects the activity of immune cells and stromal cells. We also summarize the dialog pathways by which ITM crosstalks with components within the TME, particularly the interferon pathway. This interaction between ITM and TME provides new ideas for tumor immunotherapy. By analyzing the bidirectional role of ITM in TME and combining it with its experimental and clinical status, we summarized the adjuvant role of ITM in immunotherapy. We explored the potential applications of using ITM as tumor immunotherapy, such as a healthy diet, fecal transplantation, targeted ITM, antibiotics, and probiotics, to provide a new perspective on the use of ITM in tumor immunotherapy.

The intratumoral microbiota: a new horizon in cancer immunology

Over the past decade, advancements in high-throughput sequencing technologies have led to a qualitative leap in our understanding of the role of the microbiota in human diseases, particularly in oncology. Despite the low biomass of the intratumoral microbiota, it remains a crucial component of the tumor immune microenvironment, displaying significant heterogeneity across different tumor tissues and individual patients. Although immunotherapy has emerged a major strategy for treating tumors, patient responses to these treatments vary widely. Increasing evidence suggests that interactions between the intratumoral microbiota and the immune system can modulate host tumor immune responses, thereby influencing the effectiveness of immunotherapy. Therefore, it is critical to gain a deep understanding of how the intratumoral microbiota shapes and regulates the tumor immune microenvironment. Here, we summarize the latest advancements on the role of the intratumoral microbiota in cancer immunity, exploring the potential mechanisms through which immune functions are influenced by intratumoral microbiota within and outside the gut barrier. We also discuss the impact of the intratumoral microbiota on the response to cancer immunotherapy and its clinical applications, highlighting future research directions and challenges in this field. We anticipate that the valuable insights into the interactions between cancer immunity and the intratumoral microbiota provided in this review will foster the development of microbiota-based tumor therapies.

Dry Powder Inhaler Formulation of Lactobacillus rhamnosus GG Targeting Pseudomonas aeruginosa Infection in Bronchiectasis Maintenance Therapy

The inhaled delivery of lactic acid bacteria (LAB) probiotics has been demonstrated to exert therapeutic benefits to the lungs due to LAB's immunomodulatory activities. The development of inhaled probiotics formulation, however, is in its nascent stage limited to nebulized LAB. We developed a dry powder inhaler (DPI) formulation of lactobacillus rhamnosus GG (LGG) intended for bronchiectasis maintenance therapy by spray freeze drying (SFD). The optimal DPI formulation (i.e., LGG: mannitol: lactose: leucine = 35: 45: 15: 5 wt.%) was determined based on the aerosolization efficiency (86% emitted dose and 26% respirable fraction) and LGG cell viability post-SFD (7 log CFU/mL per mg powder). The optimal DPI formulation was evaluated and compared to lyophilized naked LGG by its (1) adhesion capacity and cytotoxicity to human lung epithelium cells (i.e., A549 and 16HBE14o- cells) as well as its (2) effectiveness in inhibiting the growth and adhesion of Pseudomonas aeruginosa to lung cells. The optimal DPI of LGG exhibited similar non-cytotoxicity and adhesion capacity to lung cells to naked LGG. The DPI of LGG also inhibited the growth and adhesion of P. aeruginosa to the lung cells as effectively as the naked LGG. The present work established the feasibility of delivering the LAB probiotic by the DPI platform without adversely affecting LGG's anti-pseudomonal activities.

Gut microbiota's role in glioblastoma risk, with a focus on the mediating role of metabolites

This study employed Mendelian randomization (MR) analysis to systematically investigate the potential connections between gut microbiota and the risk of glioblastoma (GBM). We identified 12 microbial groups closely associated with the incidence risk of GBM. Subsequently, MR analysis was conducted on 1,091 blood metabolites and 309 metabolite ratios, revealing 19 metabolites that exert an impact on the occurrence of GBM. Hypothesizing that gut microbiota may influence the risk of glioblastoma multiforme by modulating these metabolites, we performed MR analyses, considering each microbial group as exposure and each metabolite as an outcome. Through these analyses, we constructed a regulatory network encompassing gut microbiota, metabolites, and GBM, providing a novel perspective for a deeper understanding of the role of the gut-brain axis in the pathogenesis of GBM. This research offers crucial insights into how gut microbiota may affect the risk of GBM by regulating specific metabolites. The identified regulatory network of the gut-brain axis may play a significant role in the formation and development of GBM, providing valuable information for future research and therapeutic interventions.

The role of airways microbiota on local and systemic diseases: a rationale for probiotics delivery to the respiratory tract

INTRODUCTION

Recent discoveries in the field of lung microbiota have enabled the investigation of new therapeutic interventions involving the use of inhaled probiotics.

AREAS COVERED

This review provides an overview of what is known about the correlation between airway dysbiosis and the development of local and systemic diseases, and how this knowledge can be exploited for therapeutic interventions. In particular, the review focused on attempts to formulate probiotics that can be deposited directly on the airways.

EXPERT OPINION

Despite considerable progress since the emergence of respiratory microbiota restoration as a new research field, numerous clinical implications and benefits remain to be determined. In the case of local diseases, once the pathophysiology is understood, manipulating the lung microbiota through probiotic administration is an approach that can be exploited. In contrast, the effect of pulmonary dysbiosis on systemic diseases remains to be clarified; however, this approach could represent a turning point in their treatment.

Cell membrane-coated nanoparticles for targeting carcinogenic bacteria

The etiology of cancers is multifactorial, with certain bacteria established as contributors to carcinogenesis. As the understanding of carcinogenic bacteria deepens, interest in cancer treatment through bacterial eradication is growing. Among emerging antibacterial platforms, cell membrane-coated nanoparticles (CNPs), constructed by enveloping synthetic substrates with natural cell membranes, exhibit significant promise in overcoming challenges encountered by traditional antibiotics. This article reviews recent advancements in developing CNPs for targeting carcinogenic bacteria. It first summarizes the mechanisms of carcinogenic bacteria and the status of cancer treatment through bacterial eradication. Then, it reviews engineering strategies for developing highly functional and multitasking CNPs and examines the emerging applications of CNPs in combating carcinogenic bacteria. These applications include neutralizing virulence factors to enhance bacterial eradication, exploiting bacterium-host binding for precise antibiotic delivery, and modulating antibacterial immunity to inhibit bacterial growth. Overall, this article aims to inspire technological innovations in developing CNPs for effective cancer treatment through oncogenic bacterial targeting.

Characterization of tumor microbiome and associations with prognosis in intrahepatic cholangiocarcinoma

BACKGROUND

The tumor microbiome has been characterized in several malignancies; however, no previous studies have investigated its role in intrahepatic cholangiocarcinoma (ICC). Hence, we explored the tumor microbiome and its association with prognosis in ICC.

METHODS

One hundred and twenty-one ICC tumor samples and 89 adjacent normal tissues were profiled by 16S rRNA sequencing. Microbial differences between tumor and adjacent nontumoral liver tissues were assessed. Tumor microbial composition was then evaluated to detect its association with prognosis. Finally, a risk score calculated by the tumor microbiota was accessed by the least absolute shrinkage and selector operator method (Lasso) to predict prognosis of ICC.

RESULTS

The tumor microbiome displayed a greater diversity than that in adjacent nontumoral liver tissues. Tumor samples were characterized by a higher abundance of Firmicutes, Actinobacteria, Bacteroidetes, and Acidobacteriota. Higher tumor microbial α diversity was associated with lymph node metastasis and predicted shortened overall survival (OS) and recurrence-free survival (RFS). A total of 11 bacteria were selected to generate the risk score by Lasso. This score showed potential in predicting OS, and was an independent risk factor for OS.

CONCLUSION

In conclusion, our study characterized the tumor microbiome and revealed its role in predicting prognosis in ICC.

Circulating microbiome DNA as biomarkers for early diagnosis and recurrence of lung cancer

Lung cancer mortality is exacerbated by late-stage diagnosis. Emerging evidence indicates the potential clinical significance of distinct microbial signatures as diagnostic and prognostic biomarkers across various cancers. However, circulating microbiome DNA (cmDNA) profiles are underexplored in lung cancer (LC). Here, whole-genome sequencing is performed on plasma of LC patients and healthy controls (HCs). Differentially enriched microbial species are identified between LC and HC. A diagnostic model is developed, which has a high sensitivity of 87.7% and achieves an AUC of 93.2% in the independent validation dataset. Crucially, this model demonstrates the capability to detect early-stage LC, achieving a sensitivity of 86.5% for stage I and 87.1% for tumors <1 cm. In addition, we construct a cmDNA model for recurrence, which precisely predicts LC recurrence after surgery. Overall, this study highlights the significant alterations of cmDNA profiles in LC, indicating its potential as biomarkers for early diagnosis and recurrence.

The airway microbiome of persons with cystic fibrosis correlates with acquisition and microbiological outcomes of incident Stenotrophomonas maltophilia infection

Rationale

Chronic infection with Stenotrophomonas maltophilia in persons with cystic fibrosis (pwCF) has been linked to an increased risk of pulmonary exacerbations and lung function decline. We sought to establish whether baseline sputum microbiome associates with risk of S. maltophilia incident infection and persistence in pwCF.

Methods

pwCF experiencing incident S. maltophilia infections attending the Calgary Adult CF Clinic from 2010-2018 were compared with S. maltophilia-negative sex, age (+/-2 years), and birth-cohort-matched controls. Infection outcomes were classified as persistent (when the pathogen was recovered in ≥50% of cultures in the subsequent year) or transient. We assessed microbial communities from prospectively biobanked sputum using V3-V4 16S ribosomal RNA (rRNA) gene sequencing, in the year preceding (Pre) (n = 57), at (At) (n = 22), and after (Post) (n = 31) incident infection. We verified relative abundance data using S. maltophilia-specific qPCR and 16S rRNA-targeted qPCR to assess bioburden. Strains were typed using pulse-field gel electrophoresis.

Results

Twenty-five pwCF with incident S. maltophilia (56% female, median 29 years, median FEV1 61%) with 33 total episodes were compared with 56 uninfected pwCF controls. Demographics and clinical characteristics were similar between cohorts. Among those with incident S. maltophilia infection, sputum communities did not cluster based on infection timeline (Pre, At, Post). Communities differed between the infection cohort and controls (n = 56) based on Shannon Diversity Index (SDI, p = 0.04) and clustered based on Aitchison distance (PERMANOVA, p = 0.01) prior to infection. At the time of incident S. maltophilia isolation, communities did not differ in SDI but clustered based on Aitchison distance (PERMANOVA, p = 0.03) in those that ultimately developed persistent infection versus those that were transient. S. maltophilia abundance within sputum was increased in samples from patients (Pre) relative to controls, measuring both relative (p = 0.004) and absolute (p = 0.001). Furthermore, S. maltophilia abundance was increased in sputum at incident infection in those who ultimately developed persistent infection relative to those with transient infection, measured relatively (p = 0.04) or absolute (p = 0.04), respectively.

Conclusion

Microbial community composition of CF sputum associates with S. maltophilia infection acquisition as well as infection outcome. Our study suggests sputum microbiome may serve as a surrogate for identifying infection risk and persistence risk.

Tumor-resident microbes: the new kids on the microenvironment block

Tumor-resident microbes (TRM) are an integral component of the tumor microenvironment (TME). TRM can influence tumor growth, distant dissemination, and response to therapies by interfering with molecular pathways in tumor cells as well as with other components of the TME. Novel technologies are improving the identification and visualization of cell type-specific microbes in the TME. The mechanisms that mediate the role of TRM at the primary tumors and metastatic sites are being elucidated. This knowledge is providing novel perspectives for targeting microbes or using microbial interventions for cancer interception or therapy.