Role of antibiotic use, plasma citrulline and blood microbiome in advanced non-small cell lung cancer patients treated with nivolumab

The Microbiome and Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a condition wherein excessive fat accumulates in the liver, leading to inflammation and potential liver damage. In this narrative review, we evaluate the tissue microbiota, how they arise and their constituent microbes, and the role of the intestinal and hepatic microbiota in MASLD. The history of bacteriophages (phages) and their occurrence in the microbiota, their part in the potential causation of MASLD, and conversely, "phage therapy" for antibiotic resistance, obesity, and MASLD, are all described. The microbiota metabolism of bile acids and dietary tryptophan and histidine is defined, together with the impacts of their individual metabolites on MASLD pathogenesis. Both periodontitis and intestinal microbiota dysbiosis may cause MASLD, and how individual microorganisms and their metabolites are involved in these processes is discussed. Novel treatment opportunities for MASLD involving the microbiota exist and include fecal microbiota transplantation, probiotics, prebiotics, synbiotics, tryptophan dietary supplements, intermittent fasting, and phages or their holins and endolysins. Although FDA is yet to approve phage therapy in clinical use, there are multiple FDA-approved clinical trials, and this may represent a new horizon for the future treatment of MASLD.

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

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

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.

Antibiotics use decreases survival in cutaneous squamous cell carcinoma patients receiving immune checkpoint inhibitors

INTRODUCTION

Immune checkpoint inhibitors (ICI) have become the first-line therapy in patients with advanced cutaneous squamous cell carcinoma (cSCC). Antibiotics (ATB) have been reported to reduce ICI response in cancers, but this has not been evaluated in cSCC.

AIM

To evaluate ATB exposure at the onset of ICI in cSCC patients and to analyze its impact on outcome.

METHODS

This single-center retrospective study included all patients who started anti-PD-1 for cSCC between March 2019 and July 2023. Exposure to ATB within 3 months prior and after the onset of ICI (ATB 3-3), including patients exposed within 1 month prior and after (ATB 1-1) were recorded. Response to ICI and survival were compared between patients with or without ATB exposure.

RESULTS

Among 104 patients included, 45 % were classified into ATB 3-3 subgroup, and 20 % to ATB 1-1. Disease control rate at 3 months were lower in both ATB 1-1 and ATB 3-3 subgroups, compared to their control group (p = 0.02 and 0.03, respectively). The overall survival and disease specific survival were lower in the ATB 1-1 subgroup, compared to control group (p = 0.04 and p = 0.01, respectively). Median progression free survival was 127 days in ATB 1-1 group, significantly lower than the control group (not reached), p = 0.005.

CONCLUSION

ATB intake was very frequent at ICI initiation in cSCC patients. In our cohort, ATB use within 1 month before or after ICI initiation significantly impacted survival, highlighting the need for caution when prescribing antibiotics in this population.

Differences in cell-associated and cell-free microbial DNA in blood

In the absence of infection, blood has previously been understood to be free of microbes. However, with advances in sequencing technology this notion has been challenged, prompting new investigations into microbial DNA within the blood of both healthy and diseased individuals. To comprehensively survey microbial DNA in blood, we separated blood into fractions (plasma, red blood cells, and buffy coat) and assessed if the microbial-DNA is cell-free by the addition of DNase to a subset of each fraction. We measured 16S rRNA gene copy number with digital droplet PCR and identified the taxonomic origin of the microbial DNA with synthetic full-length 16S rRNA gene sequencing. As a use case, we examine microbial DNA from the blood of 5 men without prostate cancer (PC), 5 men with low-grade PC, and 5 men with high-grade PC. Our study demonstrates that the majority of microbial DNA is cell-free, indicating that it is not representative of proliferating microbes. Our analyses also revealed buffy coat had the lowest number of 16S rRNA gene copies yet highest number of genera of the fractions (median 23.3 copies/μL and 10 genera) and thus may be a useful fraction to study moving forward. Additionally, microbial DNA in blood may have utility as a biomarker, as we detected disease-associated compositional differences in the plasma and buffy coat fractions. This study lays the groundwork for rigorously studying microbial DNA in blood, however larger studies are needed to confirm our disease-association findings.

Brain Tumors and Beyond: Multi-Compartment Microbiome and Mycobiome Analysis

Brain tumors are frequently diagnosed diseases in which etiology and progression largely depend on mutations and genetic factors. Additionally, recent reports document that the microbiome may influence tumor growth, tumor microenvironment, and response to therapy. Our goal was to examine the extent to which the bacterial composition-microbiota-and fungal composition-mycobiota-characteristic of the tumor and its microenvironment correlate with the composition of the gut and blood microbiota and mycobiota in five randomly selected brain tumor patients. The bacterial composition of the tumor, tumor-adjacent tissue (TAT), blood, and gut samples of the five patients were analyzed by 16S rRNA and ITS-based sequencing in order to determine the bacterial and fungal composition. The gut microbiome and mycobiome composition showed individual and tissue-specific signatures in each patient. The microbiome composition of the blood, TAT, and tumor tissue was very similar in each patient, dominated by Klebsiella, Enterococcus, Blautia, and Lactobacillus spp. In contrast, the mycobiome composition of the blood, TAT, and tumor showed a diverse, individual picture. The most common fungal species in the blood and TAT were Tomentella, Didymosphaeria, Alternaria, Penicillium, Mycosphaerella, and Discosia. The blood and TAT mycobiome were similar to each other but unique and characteristic of the patients. In contrast, in the tumor tissues, Alternaria, Malassezia, Schizophyllum, and Tomentella genus were the most common fungi genus. Our results showed that the presence of fungi in tumors shows a unique pattern that is independent of the pattern observed in the gut, blood, and tumor environment and that the effects of the mycobiome are distinct and cannot be associated with those of the microbiome. Elucidating the role of fungi in tumors and exploring the relationship between fungi and brain tumor types may open up further therapeutic options.

Circulating Cell-Free Microbial DNA Signatures and Plasma Soluble CD14 Level Are Associated with Clinical Outcomes of Anti-PD-1 Therapy in Advanced Melanoma Patients

An accumulating number of studies suggest the potential of circulating cell-free microbial DNA (cfmDNA) as a non-invasive biomarker in various diseases, including cancers. However, its value in the prediction or prognosis of clinical outcomes of immune checkpoint inhibitors (ICIs) is poorly explored. The circulating cfmDNA pool may also reflect the translocation of various microbial ligands to the circulatory system and may be associated with the increased release of soluble CD14 (sCD14) by myeloid cells. In the present study, blood samples were collected from advanced melanoma patients (n = 66) before and during the anti-PD-1 therapy (approximately 3 and 12 months after the start). Then, V3-V4 16S rRNA gene sequencing was performed to analyze the circulating cfmDNA extracted from plasma samples. Moreover, the concentration of plasma sCD14 was measured using ELISA. As a result, the differences in the circulating cfmDNA profiles were found between patients with favorable and unfavorable clinical outcomes of the anti-PD-1 and baseline signatures correlated with progression-free survival and overall survival. Moreover, there was a higher concentration of plasma sCD14 in patients with unfavorable clinical outcomes. High baseline sCD14 level and its increase during the therapy prognosticated worse survival outcomes. Taken together, this preliminary study indicates the potential of circulating cfmDNA signatures and plasma sCD14 levels as biomarkers of clinical outcomes of ICIs.

Targeting the gut and tumor microbiome in cancer treatment resistance

Therapy resistance represents a significant challenge in oncology, occurring in various therapeutic approaches. Recently, animal models and an increasing set of clinical trials highlight the crucial impact of the gut and tumor microbiome on treatment response. The intestinal microbiome contributes to cancer initiation, progression, and formation of distant metastasis. In addition, tumor-associated microbiota is considered a critical player in influencing tumor microenvironments and regulating local immune processes. Intriguingly, numerous studies have successfully identified pathogens within the gut and tumor microbiome that might be linked to a poor response to different therapeutic modalities. The unfavorable microbial composition with the presence of specific microbes participates in cancer resistance and progression via several mechanisms, including upregulation of oncogenic pathways, macrophage polarization reprogramming, metabolism of chemotherapeutic compounds, autophagy pathway modulation, enhanced DNA damage repair, inactivation of a proapoptotic cascade, and bacterial secretion of extracellular vesicles, promoting the processes in the metastatic cascade. Targeted elimination of specific intratumoral bacteria appears to enhance treatment response. However, broad-spectrum antibiotic pretreatment is mostly connected to reduced efficacy due to gut dysbiosis and lower diversity. Mounting evidence supports the potential of microbiota modulation by probiotics and fecal microbiota transplantation to improve intestinal dysbiosis and increase microbial diversity, leading to enhanced treatment efficacy while mitigating adverse effects. In this context, further research concerning the identification of clinically relevant microbiome signatures followed by microbiota-targeted strategies presents a promising approach to overcoming immunotherapy and chemotherapy resistance in refractory patients, improving their outcomes.

Blood Microbiota and Its Products: Mechanisms of Interference with Host Cells and Clinical Outcomes

In healthy conditions, blood was considered a sterile environment until the development of new analytical approaches that allowed for the detection of circulating bacterial ribosomal DNA. Currently, debate exists on the origin of the blood microbiota. According to advanced research using dark field microscopy, fluorescent in situ hybridization, flow cytometry, and electron microscopy, so-called microbiota have been detected in the blood. Conversely, others have reported no evidence of a common blood microbiota. Then, it was hypothesized that blood microbiota may derive from distant sites, e.g., the gut or external contamination of blood samples. Alteration of the blood microbiota's equilibrium may lead to dysbiosis and, in certain cases, disease. Cardiovascular, respiratory, hepatic, kidney, neoplastic, and immune diseases have been associated with the presence of Gram-positive and Gram-negative bacteria and/or their products in the blood. For instance, lipopolysaccharides (LPSs) and endotoxins may contribute to tissue damage, fueling chronic inflammation. Blood bacteria can interact with immune cells, especially with monocytes that engulf microorganisms and T lymphocytes via spontaneous binding to their membranes. Moreover, LPSs, extracellular vesicles, and outer membrane vesicles interact with red blood cells and immune cells, reaching distant organs. This review aims to describe the composition of blood microbiota in healthy individuals and those with disease conditions. Furthermore, special emphasis is placed on the interaction of blood microbiota with host cells to better understand disease mechanisms.

Potential mechanisms and targeting strategies of the gut microbiota in antitumor immunity and immunotherapy

BACKGROUND

Immunotherapies, notably immune checkpoints inhibitors that target programmed death 1/programmed death ligand 1(PD-1/PD-L1) and cytotoxic T lymphocyte-associated antigen 4 (CTLA-4), had profoundly changed the way advanced and metastatic cancers are treated and dramatically improved overall and progression-free survival.

AIMS

This review article aimed to explore the underlying molecular mechanisms by which the gut microbiota affects antitumor immunity and the efficacy of cancer immunotherapy.

METHODS

We summarized the latest knowledge supporting the associations among the gut microbiota, antitumor immunity, and immunotherapy. Moreover, we disscussed the therapeutic strategy for improving immunotherapy efficacy by modulating gut microbiota in cancer treatment.

RESULTS

The potential molecular mechanisms underlying these associations are explained in terms of four aspects: immunomodulation, molecular mimicry, mamps, and microbial metabolites.

CONCLUSION

The gut microbiota significantly impacts antitumor immunity and alters the effectiveness of cancer immunotherapy.

Antibiotic-associated neutropenia is marked by depletion of intestinal Lachnospiraceae in pediatric patients

Hematologic side effects are associated with prolonged antibiotic exposure in up to 34% of patients. Neutropenia, reported in 10-15% of patients, increases the risk of sepsis and death. Murine studies have established a link between the intestinal microbiota and normal hematopoiesis. We sought to identify predisposing factors, presence of microbiota-derived metabolites, and changes in intestinal microbiota composition in otherwise healthy pediatric patients who developed neutropenia after prolonged courses of antibiotics. In this multi-center study, patients with infections requiring anticipated antibiotic treatment of two or more weeks were enrolled. Stool samples were obtained at the start and completion of antibiotics and at the time of neutropenia. We identified 10 patients who developed neutropenia on antibiotics and 29 controls matched for age, sex, race, and ethnicity. Clinical data demonstrated no association between neutropenia and type of infection or type of antibiotic used; however intensive care unit admission and length of therapy were associated with neutropenia. Reduced intestinal microbiome richness and decreased abundance of Lachnospiraceae family members correlated with neutropenia. Untargeted stool metabolomic profiling revealed several metabolites that were depleted exclusively in patients with neutropenia, including members of the urea cycle pathway, pyrimidine metabolism and fatty acid metabolism that are known to be produced by Lachnospiraceae . Our study confirms a relationship between intestinal microbiota disruption and abnormal hematopoiesis and identifies taxa and metabolites likely to contribute to microbiota-sustained hematopoiesis. As the microbiome is a key determinant of stem cell transplant and immunotherapy outcomes, these findings are likely to be of broad significance.

Key Points

Neutropenia occurred in 17% of patients receiving prolonged antibiotic therapy.We found no association between neutropenia and type of infection or class of antibiotic used. Development of neutropenia after prolonged antibiotic treatment was associated with decreased prevalence of Lachnospiraceae and Lachnospiraceae metabolites such as citrulline.

Biomarkers and computational models for predicting efficacy to tumor ICI immunotherapy

Numerous studies have shown that immune checkpoint inhibitor (ICI) immunotherapy has great potential as a cancer treatment, leading to significant clinical improvements in numerous cases. However, it benefits a minority of patients, underscoring the importance of discovering reliable biomarkers that can be used to screen for potential beneficiaries and ultimately reduce the risk of overtreatment. Our comprehensive review focuses on the latest advancements in predictive biomarkers for ICI therapy, particularly emphasizing those that enhance the efficacy of programmed cell death protein 1 (PD-1)/programmed cell death-ligand 1 (PD-L1) inhibitors and cytotoxic T-lymphocyte antigen-4 (CTLA-4) inhibitors immunotherapies. We explore biomarkers derived from various sources, including tumor cells, the tumor immune microenvironment (TIME), body fluids, gut microbes, and metabolites. Among them, tumor cells-derived biomarkers include tumor mutational burden (TMB) biomarker, tumor neoantigen burden (TNB) biomarker, microsatellite instability (MSI) biomarker, PD-L1 expression biomarker, mutated gene biomarkers in pathways, and epigenetic biomarkers. TIME-derived biomarkers include immune landscape of TIME biomarkers, inhibitory checkpoints biomarkers, and immune repertoire biomarkers. We also discuss various techniques used to detect and assess these biomarkers, detailing their respective datasets, strengths, weaknesses, and evaluative metrics. Furthermore, we present a comprehensive review of computer models for predicting the response to ICI therapy. The computer models include knowledge-based mechanistic models and data-based machine learning (ML) models. Among the knowledge-based mechanistic models are pharmacokinetic/pharmacodynamic (PK/PD) models, partial differential equation (PDE) models, signal networks-based models, quantitative systems pharmacology (QSP) models, and agent-based models (ABMs). ML models include linear regression models, logistic regression models, support vector machine (SVM)/random forest/extra trees/k-nearest neighbors (KNN) models, artificial neural network (ANN) and deep learning models. Additionally, there are hybrid models of systems biology and ML. We summarized the details of these models, outlining the datasets they utilize, their evaluation methods/metrics, and their respective strengths and limitations. By summarizing the major advances in the research on predictive biomarkers and computer models for the therapeutic effect and clinical utility of tumor ICI, we aim to assist researchers in choosing appropriate biomarkers or computer models for research exploration and help clinicians conduct precision medicine by selecting the best biomarkers.

Circulating microbiome analysis in patients with perioperative anaphylaxis

Background

Perioperative anaphylaxis is a rare and acute systemic manifestation of drug-induced hypersensitivity reactions that occurs following anesthesia induction; the two main classes of drugs responsible for these reactions being neuromuscular blocking agents (NMBA) and antibiotics. The sensitization mechanisms to the drugs are not precisely known, and few risk factors have been described. A growing body of evidence underlines a link between occurrence of allergy and microbiota composition. However, no data exist on microbiota in perioperative anaphylaxis. The aim of this study was to compare circulating microbiota richness and composition between perioperative anaphylaxis patients and matched controls.

Methods

Circulating 16s rDNA was quantified and sequenced in serum samples from 20 individuals with fully characterized IgE-mediated NMBA-related anaphylaxis and 20 controls matched on sex, age, NMBA received, type of surgery and infectious status. Microbiota composition was analyzed with a published bioinformatic pipeline and links with patients clinical and biological data investigated.

Results

Analysis of microbiota diversity showed that anaphylaxis patients seem to have a richer circulating microbiota than controls, but no major differences of composition could be detected with global diversity indexes. Pairwise comparison showed a difference in relative abundance between patients and controls for Saprospiraceae, Enterobacteriaceae, Veillonellaceae, Escherichia-Shigella, Pseudarcicella, Rhodoferax, and Lewinella. Some taxa were associated with concentrations of mast cell tryptase and specific IgE.

Conclusion

We did not find a global difference in terms of microbiota composition between anaphylaxis patient and controls. However, several taxa were associated with anaphylaxis patients and with their biological data. These findings must be further confirmed in different settings to broaden our understanding of drug anaphylaxis pathophysiology and identify predisposition markers.

Antibiotic adoption effects on nutrition and quality of life in lung cancer patients undergoing radiotherapy and chemotherapy: A meta-analysis

BACKGROUND

Lung cancer (LC) is one of the leading causes of death worldwide. Treatment methodologies such as chemotherapy and radiotherapy have improved patient survival rates. Nevertheless, these treatments can also lead to adverse reactions and impact patients' nutritional status and quality of life (QOL). Antibiotics are commonly used for treating infections, but there is still controversy regarding their potential adverse effects on LC patients.

OBJECTIVE

This work aimed to investigate the impact of antibiotic adoption on the nutritional status and QOL of LC patients undergoing radiotherapy or chemotherapy, providing valuable insights for the clinical management of LC.

METHODS

A meta-analysis approach was employed to comprehensively evaluate the relationship by synthesizing relevant literature. Published studies were identified through searches in databases such as PubMed, EMBASE, Cochrane Library, Web of Science, and CNKI. The inclusion criteria encompassed randomized controlled trials, cohort studies, and cross-sectional studies. Assessment indicators included patient weight, BMI, hemoglobin levels, and QOL. Meta-analysis was conducted using software such as the Cochrane Collaboration and RevMan5.3. Heterogeneity was evaluated using the Higgins I2 index, where values between 25% and 50% indicate moderate heterogeneity, and values greater than 50% indicate substantial heterogeneity.

RESULTS

12 eligible studies involving 1,917 patients were finally included. LC patients who received antibiotics during radiotherapy or chemotherapy were found to have a higher risk of malnutrition. The antibiotic group exhibited a more significant decrease in body mass index (BMI) (P< 0.05) and lower serum albumin levels (P< 0.05) versus the control (C) group. Additionally, the overall QOL scores in the antibiotic group were dramatically lower than those in the C group, showing a significant difference with P< 0.05. Sensitivity analysis indicated that the overall conclusions of this work were robust and unbiased.

CONCLUSION

Antibiotics in LC patients undergoing radiotherapy or chemotherapy may increase the risk of malnutrition and decrease their QOL. Hence, physicians should carefully consider antibiotics and take necessary preventive measures and supportive treatments to improve LC patients' nutritional status and QOL.

Antibiotic treatment and survival in non-small cell lung cancer patients receiving immunotherapy: a systematic review and meta-analysis

Background

In patients with non-small cell lung cancer (NSCLC), immune checkpoint inhibitors (ICIs) are an effective mode of treatment. Despite their efficacy, responses to ICIs have been shown to differ based on several factors; for example, antibiotic use prior to and/or during immunotherapy has been associated with lower survival in NSCLC patients. The objective of this study is to provide an updated review of the literature and to fill in important knowledge gaps by accounting for potential confounding in the relationship between ICIs and survival.

Methods

We performed a systematic review and meta-analysis on peer-reviewed studies that examined the effects of antibiotic use on overall survival (OS) and progression-free survival (PFS) in NSCLC patients treated with ICIs. We searched MEDLINE for studies published up to June 30th, 2023 that included NSCLC patients treated with anti-programmed cell death protein 1 (PD-1) or programmed death-ligand 1 (PD-L1) agents, who received antibiotics before and/or during immunotherapy, and included a control group who did not receive antibiotics and had available data on the associations between antibiotics and OS and PFS. We calculated aggregated crude OS and PFS for all studies, and only for studies that reported multivariable hazard ratios (HRs). Risk of bias was assessed using a funnel plot. All results were synthesized and displayed using the metaphor statistical package in R, version 4.2.1.

Results

Nineteen studies, conducted between 2017 and 2022, met the inclusion criteria, and included 2,932 patients with advanced and/or metastatic NSCLC. Compared to those who did not receive antibiotics, immunotherapy patients who did had a significantly reduced PFS (HR: 1.22, 95% CI: 1.03-1.44) and OS (HR: 1.56, 95% CI: 1.23-1.99). Adjusted HRs were even more pronounced (OS HRadj: 1.67, 95% CI: 1.23-2.27, PFS HRadj: 1.64, 95% CI: 1.16-2.32).

Conclusions

NSCLC patients treated with antibiotics have significantly lowered survival compared with patients not treated with antibiotics. These results support the hypothesis that antibiotic use in conjunction with ICI among NSCLC patients lowers survival. Limitations of this analysis include the use of studies available only on a single database, limiting the literature search to NSCLC patients, which may impact the generalizability of results to other cancer patient populations, and the inability to account for and adjust the estimates for the same variables (e.g., age, sex) across all studies. Nevertheless, our findings underscore the importance of taking antibiotic use into consideration when using ICIs to treat NSCLC and suggest that confounders should be taken into account when designing future similar studies.

Gut-lung axis: role of the gut microbiota in non-small cell lung cancer immunotherapy

Immunotherapy for non-small cell lung cancer (NSCLC) has advanced considerably over the past two decades. In particular, immune checkpoint inhibitors are widely used for treating NSCLC. However, the overall cure and survival rates of patients with NSCLC remain low. Therefore, continuous investigation into complementary treatments is necessary to expand the clinical advantages of immunotherapy to a larger cohort of patients with NSCLC. Recently, the distinctive role of the gut microbiota (GM) in the initiation, progression, and dissemination of cancer has attracted increasing attention. Emerging evidence indicates a close relationship between the gut and lungs, known as the gut-lung axis (GLA). In this review, we aim to provide a comprehensive summary of the current knowledge regarding the connection between the GM and the outcomes of immunotherapy in NSCLC, with particular focus on the recent understanding of GLA. Overall, promising GM-based therapeutic strategies have been observed to improve the effectiveness or reduce the toxicity of immunotherapy in patients with NSCLC, thus advancing the utilization of microbiota precision medicine.

The Gut Microbiome from a Biomarker to a Novel Therapeutic Strategy for Immunotherapy Response in Patients with Lung Cancer

The gastrointestinal microbiome has been shown to play a key role in determining the responses to cancer immunotherapy, including immune checkpoint inhibitor (ICI) therapy and CAR-T. In patients with non-small cell lung cancer (NSCLC), increasing evidence suggests that a microbiome composition signature is associated with clinical response to ICIs as well as with the development of immune-related adverse events. In support of this, antibiotic (ATB)-related dysbiosis has been consistently linked with the deleterious impact of ICI response, shortening the overall survival (OS) among patients on ATBs prior to ICI initiation. In parallel, several preclinical experiments have unravelled various strategies using probiotics, prebiotics, diet, and fecal microbiota transplantation as new therapeutic tools to beneficially shift the microbiome and enhance ICI efficacy. These approaches are currently being evaluated in clinical trials and have achieved encouraging preliminary results. In this article, we reviewed the recent studies on the gut microbiome as a potential biomarker and an adjuvant therapy to ICIs in NSCLC patients.

Pharmacometabolomics of trabectedin in metastatic soft tissue sarcoma patients

Objective: Trabectedin is an anti-cancer drug commonly used for the treatment of patients with metastatic soft tissue sarcoma (mSTS). Despite its recognized efficacy, significant variability in pharmacological response has been observed among mSTS patients. To address this issue, this pharmacometabolomics study aimed to identify pre-dose plasma metabolomics signatures that can explain individual variations in trabectedin pharmacokinetics and overall clinical response to treatment. Methods: In this study, 40 mSTS patients treated with trabectedin administered by 24 h-intravenous infusion at a dose of 1.5 mg/m2 were enrolled. The patients' baseline plasma metabolomics profiles, which included derivatives of amino acids and bile acids, were analyzed using multiple reaction monitoring LC-MS/MS together with their pharmacokinetics profile of trabectedin. Multivariate Partial least squares regression and univariate statistical analyses were utilized to identify correlations between baseline metabolite concentrations and trabectedin pharmacokinetics, while Partial Least Squares-Discriminant Analysis was employed to evaluate associations with clinical response. Results: The multiple regression model, derived from the correlation between the AUC of trabectedin and pre-dose metabolomics, exhibited the best performance by incorporating cystathionine, hemoglobin, taurocholic acid, citrulline, and the phenylalanine/tyrosine ratio. This model demonstrated a bias of 4.6% and a precision of 17.4% in predicting drug AUC, effectively accounting for up to 70% of the inter-individual pharmacokinetic variability. Through the use of Partial least squares-Discriminant Analysis, cystathionine and hemoglobin were identified as specific metabolic signatures that effectively distinguish patients with stable disease from those with progressive disease. Conclusions: The findings from this study provide compelling evidence to support the utilization of pre-dose metabolomics in uncovering the underlying causes of pharmacokinetic variability of trabectedin, as well as facilitating the identification of patients who are most likely to benefit from this treatment.

Identification of a novel plasma metabolite panel as diagnostic biomarker for hepatocellular carcinoma

BACKGROUND AND AIMS

Metabolic reprogramming is one of the hallmarks of cancer. Hepatocellular carcinoma (HCC) is one of the most lethal malignancy camcer, but the early diagnosis of HCC remains difficult. In this study, we searched for potential plasma metabolite biomarkers of HCC.

METHODS

A total of plasma samples of 104 HCC, 76 cirrhosis and 10 healthy subjects were assessed and validated through Gas chromatography-Mass spectrometry. Receiver-operating characteristic curves (ROC) combined with multivariate statistical analyses were used to assess the diagnostic performance of metabolites and combinations.

RESULTS

10 metabolites in screening cohort were significantly changed in the plasma of HCC patients. Multivariate logistic regression analysis of candidate metabolites in validation cohort showed that N-formylglycine, oxoglutaric acid, citrulline and heptaethylene glycol could distinguish HCC from cirrhosis. The combination of these four metabolites showed a better performance than AFP with the Area Under the Curve (AUC), sensitivity, specificity as 0.940, 84.00%, 97.56%, respectively. In further, the panel of N-formylglycine, heptaethylene glycol and citrulline can more effectively discriminate early stage HCC from cirrhosis than AFP (AUC: 0.835 vs. 0.634). Finally, heptaethylene glycol could significantly inhibit the proliferation, migration and invasion of HCC cells in vitro.

CONCLUSION

The combination of plasma N-formylglycine, oxoglutaric acid, citrulline, and heptaethylene glycol can be an efficient novel diagnostic biomarker for HCC.

The Blood Microbiome and Health: Current Evidence, Controversies, and Challenges

Blood is conventionally thought to be sterile. However, emerging evidence on the blood microbiome has started to challenge this notion. Recent reports have revealed the presence of genetic materials of microbes or pathogens in the blood circulation, leading to the conceptualization of a blood microbiome that is vital for physical wellbeing. Dysbiosis of the blood microbial profile has been implicated in a wide range of health conditions. Our review aims to consolidate recent findings about the blood microbiome in human health and to highlight the existing controversies, prospects, and challenges around this topic. Current evidence does not seem to support the presence of a core healthy blood microbiome. Common microbial taxa have been identified in some diseases, for instance, Legionella and Devosia in kidney impairment, Bacteroides in cirrhosis, Escherichia/Shigella and Staphylococcus in inflammatory diseases, and Janthinobacterium in mood disorders. While the presence of culturable blood microbes remains debatable, their genetic materials in the blood could potentially be exploited to improve precision medicine for cancers, pregnancy-related complications, and asthma by augmenting patient stratification. Key controversies in blood microbiome research are the susceptibility of low-biomass samples to exogenous contamination and undetermined microbial viability from NGS-based microbial profiling, however, ongoing initiatives are attempting to mitigate these issues. We also envisage future blood microbiome research to adopt more robust and standardized approaches, to delve into the origins of these multibiome genetic materials and to focus on host-microbe interactions through the elaboration of causative and mechanistic relationships with the aid of more accurate and powerful analytical tools.

Short- and Long-term Repercussions of Vancomycin on Immune Surveillance and the Efficacy of Antitumor Treatments

ABSTRACT

Although antibiotic is a major contributor to shifts in the intestinal flora that may persist for up to several months after cessation, it is now increasingly recognized that its prescription may differentially influence clinical outcome of different anticancer treatments. Intense clinical and basic research efforts aim then at gaining sufficient insights about how the cooperative action between the intestinal ecosystem and immune surveillance modulates the efficacy of anticancer treatments. In this review, we summarize multiple levels of knowledge between vancomycin exposure, the gut microbiota, and a meaningful therapeutic response. Furthermore, we discuss the mode of action of antibiotic therapy that is prescribed for prophylaxis of bacteremia and neutropenia and outline the opportunity for judiciously improving the efficacy of anticancer drugs.

Effectiveness and safety of camrelizumab in inoperable or advanced non-small cell lung cancer patients: a multicenter real-world retrospective observational study (CTONG2004-ADV)

Background

Camrelizumab plus chemotherapy have been approved as standards for the treatment of advanced non-small cell lung cancer (NSCLC) patients based on two phase III trials. However, clinical trial results may not be representative of the general population, as clinical trials often have specific inclusion and exclusion criteria. Our research aims to investigate the real-world effectiveness and safety of camrelizumab in inoperable or advanced NSCLC patients.

Methods

This multicenter retrospective observational study included inoperable or advanced pathologically confirmed NSCLC patients who received at least one dose of camrelizumab at 22 hospitals. Clinical and follow-up data of camrelizumab were collected retrospectively from the medical records. The primary outcome was the objective response rate (ORR) and secondary outcomes were disease control rate (DCR), 6-month progression-free survival (PFS), overall survival (OS), and treatment-related adverse events (TRAEs). Multivariate logistic and Cox regression analyses were applied to identify potential predictive factors of ORR and PFS, respectively.

Results

Between July 2019 and March 2021, 336 patients were included. Adenocarcinoma was seen in 58.4% and stage IV disease in 69.3%. Twenty-nine (8.6%) had liver metastasis at baseline. Most patients received camrelizumab in the first-line setting (74.1%) and in combination with chemotherapy (60.7%). The ORR was 40.2% [95% confidence interval (CI): 34.9-45.6%] and DCR was 85.1% (95% CI: 81.3-88.9%), while the 6-month PFS and OS rates were 73.0% (95% CI: 67.1-78.0%) and 93.1% (95% CI: 89.8-95.4%), respectively. In multivariate analyses, liver metastasis [odds ratio (OR), 0.324; 95% CI: 0.115-0.915; P=0.033] and increasing lines of camrelizumab treatment (vs. first line, second line: OR, 0.347; 95% CI: 0.162-0.741; P=0.006; ≥ third line: OR, 0.126; 95% CI: 0.043-0.367; P<0.001) were negatively associated, while a longer duration of camrelizumab treatment was positively associated with ORR and PFS. TRAEs were recorded in 164 (48.8%) patients, without new safety signal.

Conclusions

We conducted a comprehensive overview of the effectiveness and safety profile of camrelizumab in a broader NSCLC population in real world NSCLC patients, and subgroup analysis indicated the presence of liver metastasis was associated with worse outcomes.

Antibiotic Treatment is an Independent Poor Risk Factor in NSCLC But Not in Melanoma Patients Who had Received Anti-PD-1/L1 Monotherapy

BACKGROUND

Antibiotic treatment may reduce the efficacy of cancer immunotherapy by disrupting gut microbiome. We aimed to study the association of antibiotics and survival outcomes in advanced cutaneous melanoma and non-small-cell lung cancer (NSCLC) patients who had received anti-PD-1/L1 monotherapy.

PATIENTS AND METHODS

A total of 222 melanoma and 199 NSCLC patients had received anti-PD-1/L1 monotherapy in 5 Finnish hospitals between January 2014 and December 2020. Clinical characteristics, antibiotic and corticosteroid treatment, and survival outcomes were retrospectively collected from hospital and national medical records.

RESULTS

There were 32% of melanoma and 31% of NSCLC patients who had received antibiotic treatment (ABT) 3 months before to 1 month after the first anti-PD-1/L1 antibody infusion. In survival analyses, early antibiotic treatment was associated with inferior overall survival (OS) (ABT 19.2 [17.6-43.7] vs. no ABT 35.6 [29.3-NA] months, P = .033) but not with inferior progression-free survival (PFS) (ABT 5.8 [3.0-12.6] vs. no ABT 10.2 [7.7-15.3] months, P = .3) in melanoma patients and with inferior OS (ABT 8.6 [6.4-12.3] vs. no ABT 18.5 [15.1-21.6] months, P < .001) and PFS (ABT 2.8 [2.1-4.5] vs. no ABT 5.6 [4.4-8.0] months, P = .0081) in NSCLC patients. In multivariable analyses, ABT was not an independent risk-factor for inferior OS and PFS in melanoma but was associated with inferior OS (hazard ratio [HR] 2.12 [1.37-3.28]) and PFS (HR 1.65 [1.10-2.47]) in NSCLC after adjusted for other risk factors.

CONCLUSIONS

Early ABT was an independent poor risk factor in NSCLC patients who had received anti-PD-1/L1 monotherapy but not in melanoma patients. The weight of ABT as a poor risk factor might depend on other prognostic factors in different cancers.

A systematic review and meta-analysis evaluating the impact of antibiotic use on the clinical outcomes of cancer patients treated with immune checkpoint inhibitors

Background

Immune checkpoint inhibitors (ICIs) have considerably improved patient outcomes in various cancer types, but their efficacy remains poorly predictable among patients. The intestinal microbiome, whose balance and composition can be significantly altered by antibiotic use, has recently emerged as a factor that may modulate ICI efficacy. The objective of this systematic review and meta-analysis is to investigate the impact of antibiotics on the clinical outcomes of cancer patients treated with ICIs.

Methods

PubMed and major oncology conference proceedings were systematically searched to identify all studies reporting associations between antibiotic use and at least one of the following endpoints: Overall Survival (OS), Progression-Free Survival (PFS), Objective Response Rate (ORR) and Progressive Disease (PD) Rate. Pooled Hazard Ratios (HRs) for OS and PFS, and pooled Odds Ratios (ORs) for ORR and PD were calculated. Subgroup analyses on survival outcomes were also performed to investigate the potential differential effect of antibiotics according to cancer types and antibiotic exposure time windows.

Results

107 articles reporting data for 123 independent cohorts were included, representing a total of 41,663 patients among whom 11,785 (28%) received antibiotics around ICI initiation. The pooled HRs for OS and PFS were respectively of 1.61 [95% Confidence Interval (CI) 1.48-1.76] and 1.45 [95% CI 1.32-1.60], confirming that antibiotic use was significantly associated with shorter survival. This negative association was observed consistently across all cancer types for OS and depending on the cancer type for PFS. The loss of survival was particularly strong when antibiotics were received shortly before or after ICI initiation. The pooled ORs for ORR and PD were respectively of 0.59 [95% CI 0.47-0.76] and 1.86 [95% CI 1.41-2.46], suggesting that antibiotic use was significantly associated with worse treatment-related outcomes.

Conclusion

As it is not ethically feasible to conduct interventional, randomized, controlled trials in which antibiotics would be administered to cancer patients treated with ICIs to demonstrate their deleterious impact versus control, prospective observational studies and interventional trials involving microbiome modifiers are crucially needed to uncover the role of microbiome and improve patient outcomes. Such studies will reduce the existing publication bias by allowing analyses on more homogeneous populations, especially in terms of treatments received, which is not possible at this stage given the current state of the field. In the meantime, antibiotic prescription should be cautiously considered in cancer patients receiving ICIs.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42019145675.

A blood-based circulating microbial metagenomic panel for early diagnosis and prognosis of oesophageal adenocarcinoma

BACKGROUND

Emerging evidence indicates the potential clinical significance of specific microbial signatures as diagnostic and prognostic biomarkers, in multiple cancers. However, to date, no studies have systematically interrogated circulating metagenome profiling in oesophageal adenocarcinoma (EAC) patients, particularly as novel non-invasive, early detection, surveillance and prognostic classifiers.

METHODS

Metagenome sequencing was performed on 81 serum specimens collected across EAC spectrum, with sequencing reads classified using Bracken and MetaPhlAn3. Followed by the Linear Discriminant Analysis effect size (LEfSe) method to identify microbial profiles between groups. Logistic regression and Kaplan-Meier analyses were used to build classifiers.

RESULTS

A significant loss of alpha and beta diversity was identified in serum specimens from EAC patients. We observed a shift in microbial taxa between each group-at the phylum, genus, and species level-with Lactobacillus sakei as the most prominent species in gastroesophageal reflux (GERD) vs other patient groups. Interestingly, LEfSe analysis identified a complete loss of Lactobacillus (L. Sakei and L. Curvatus), Collinsella stercoris and Bacteroides stercoris but conversely a significant increase in Escherichia coli in patients with EAC. Finally, we developed a metagenome panel that discriminated EAC from GERD patients with an AUC value of 0.89 (95% CI: 0.78-0.95; P < 0.001) and this panel in conjunction with the TNM stage was a robust predictor of overall survival (≥24 months; AUC = 0.84 (95% CI: 0.66-0.92; P = 0.006)).

CONCLUSION

This study firstly describes unique blood-based microbial profiles in patients across EAC carcinogenesis, that are further utilised to establish a novel circulating diagnostic and prognostic metagenomic signature for EAC.

TRANSLATIONAL RELEVANCE

Accumulating data indicates the clinical relevance of specific microbial signatures as diagnostic and prognostic biomarkers, in multiple cancers. However, to date, no studies have systematically interrogated circulating metagenome profiling in patients with oesophageal adenocarcinoma (EAC). Herein, we performed metagenome sequencing in serum specimens from EAC patients 81 collected across EAC spectrum and observed a significant loss of alpha and beta diversity, with a shift in microbial taxa between each group-at the phylum, genus, and species level-with Lactobacillus sakei as the most prominent species in gastroesophageal reflux (GERD) vs other patient groups. Interestingly, LEfSe analysis identified a complete loss of Lactobacillus (L. Sakei and L. Curvatus), Collinsella stercoris and Bacteroides stercoris but conversely a significant increase in Escherichia coli in patients with EAC. Finally, we developed a metagenome panel that discriminated EAC from GERD patients with an AUC value of 0.89 and this panel, in conjunction with the TNM stage, was a robust predictor of overall survival. This study for the first time describes unique blood-based microbial profiles in patients across EAC carcinogenesis, that are further utilised to establish a novel circulating diagnostic and prognostic metagenomic signature for EAC.

Microbiota and Extracellular Vesicles in Anti-PD-1/PD-L1 Therapy

Simple Summary

Immune checkpoint inhibitors (ICI) targeting PD-1/PD-L1 have emerged as contemporary treatments for a variety of cancers. However, the efficacy of antibody-based ICIs could be further enhanced. Microbiota have been demonstrated to be among the vital factors governing cancer progression and response to therapy in patients. Bacteria secrete extracellular vesicles carrying bioactive metabolites within their cargo that can cross physiological barriers, selectively accumulate near tumor cells, and alter the tumor microenvironment. Extracellular vesicles, particularly those derived from bacteria, could thus be of promising assistance in refining the treatment outcomes for anti-PD-1/PD-L1 therapy. The potentiality of microbiota-derived extracellular vesicles in improving the currently used treatments and presenting new therapeutic avenues for cancer has been featured in this review.

Abstract

Cancer is a deadly disease worldwide. In light of the requisite of convincing therapeutic methods for cancer, immune checkpoint inhibition methods such as anti-PD-1/PD-L1 therapy appear promising. Human microbiota have been exhibited to regulate susceptibility to cancer as well as the response to anti-PD-1/PD-L1 therapy. However, the probable contribution of bacterial extracellular vesicles (bEVs) in cancer pathophysiology and treatment has not been investigated much. bEVs illustrate the ability to cross physiological barriers, assemble around the tumor cells, and likely modify the tumor microenvironment (EVs). This systematic review emphasizes the correlation between cancer-associated extracellular vesicles, particularly bEVs and the efficacy of anti-PD-1/PD-L1 therapy. The clinical and pharmacological prospective of bEVs in revamping the contemporary treatments for cancer has been further discussed.

Citrulline protects against LPS‑induced acute lung injury by inhibiting ROS/NLRP3‑dependent pyroptosis and apoptosis via the Nrf2 signaling pathway

Acute lung injury (ALI) is a common complication in patients with sepsis and is accompanied by high mortality. The present study aimed to investigate if the organic compound citrulline has a protective against lipopolysaccharide (LPS)-stimulated ALI and its potential mechanisms. ALI was induced in mice by intraperitoneal (i.p.) injection of LPS (10 mg/kg). Citrulline (1 g/kg/day) was administrated i.p. 7 days prior to LPS injection. Mouse lung vascular endothelial cells (MLVECs) were divided into five groups: Control, LPS, LPS + Cit, LPS + N-acetyl-L-cysteine (NAC) and LPS + Cit + ML385. Lung injury was determined by morphology changes. Apoptosis and pyroptosis were detected using western blot analysis and immunofluorescence. The present results indicated that citrulline can significantly attenuate ALI. Citrulline pretreatment decreased the expression of NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome and decreased pyroptosis and apoptosis. Intervention with the total reactive oxygen species (ROS) scavenger N-acetyl-L-cysteine attenuated NLRP3 inflammasome-associated pyroptosis and apoptosis in LPS-treated MLVECs. Citrulline pretreatment inhibited pyroptotic cell death and apoptosis induced by LPS. Citrulline decreased accumulation of intracellular ROS and activated the nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Furthermore, the Nrf2 inhibitor ML385 reversed ROS generation, NLRP3 inflammasome-mediated pyroptosis and apoptosis suppressed by citrulline. In summary, the present data demonstrated that citrulline may confer protection against ALI via inhibition of ROS/NLRP3 inflammasome-dependent pyroptosis and apoptosis via the Nrf2 signaling pathway.

The gut microbiome, immune check point inhibition and immune-related adverse events in non-small cell lung cancer

Systemic treatment options for patients with lung cancer have expanded in recent years, with a number of immunotherapeutic strategies now in our treatment armamentarium. Toxicity of and resistance to treatment hold a major stake in lung cancer morbidity and mortality. Herein, we summarise the background, current evidence and potential mechanisms underlying the role of the commensal gut microbiota in immunotherapy outcomes such as response and toxicity in patients with non-small cell lung cancer (NSCLC).

Different classes of antibiotics exhibit disparate negative impacts on the therapeutic efficacy of immune checkpoint inhibitors in advanced non-small cell lung cancer patients

It has been reported that antibiotics (ATBs) have adverse effect on the efficacy of treatment with immune checkpoint inhibitors (ICIs) in cancer patients. Since different classes of ATBs have different antibacterial spectrum, we aimed to study whether all ATBs had similar or different negative effects on the clinical outcomes of ICIs in patients with advanced non-small cell lung cancer (NSCLC). Patients with advanced NSCLC who received ICIs were included in this retrospective study and grouped by the class of ATBs they had used around the ICIs treatment time. The overall survival (OS) and the progression free survival (PFS) of patients among these groups were compared using Kaplan-Meier method and Cox proportional hazards model. A total of 148 eligible patients were enrolled, and 80 patients used ATBs. The results indicated that quinolones had no significant negative consequence on the clinical outcomes, while β-lactams significantly shortened the OS and PFS of patients. Furthermore, patients exposed to the combination of β-lactams and quinolones suffered the worst OS and PFS. Moreover, the subgroup analysis of β-lactams revealed that only penicillins, but not carbapenems and cephalosporins, markedly reduced both OS and PFS. In addition to the class of ATBs used, the time frame of ATBs used also affected the clinical outcomes of ICIs therapy. Patients receiving ATBs within 60 days prior to and 30 days after the initiation of ICI treatment had significantly shorter OS and PFS compared with those who did not use ATBs. This study demonstrated that different classes of ATBs had disparate negative impacts on the clinical outcomes, and the use of β-lactams, especially penicillins, should be avoided in advanced NSCLC patients who are receiving or scheduled to receive ICIs within 60 days.

Interaction between Bacteria and the Immune System for Cancer Immunotherapy: The α-GalCer Alliance

Non-conventional T cells, such as γδ T and invariant natural killer T (iNKT) cells, are emerging players in fighting cancer. Alpha-galactosylceramide (α-GalCer) is used as an exogenous ligand to activate iNKT cells. Human cells don’t have a direct pathway producing α-GalCer, which, however, can be produced by bacteria. We searched the literature for bacteria strains that are able to produce α-GalCer and used available sequencing data to analyze their presence in human tumor tissues and their association with survival. The modulatory effect of antibiotics on the concentration of α-GalCer was analyzed in mice. The human gut bacteria Bacteroides fragilis, Bacteroides vulgatus, and Prevotella copri produce α-GalCer structures that are able to activate iNKT cells. In mice, α-GalCer was depleted upon treatment with vancomycin. The three species were detected in colon adenocarcinoma (COAD) and rectum adenocarcinoma tissues, and Prevotella copri was also detected in bone tumors and glioblastoma tissues. Bacteroides vulgatus in COAD tissues correlated with better survival. In conclusion, α-GalCer-producing bacteria are part of the human gut microbiome and can infiltrate tumor tissues. These results suggest a new mechanism of interaction between bacteria and immune cells: α-GalCer produced by bacteria may activate non-conventional T cells in tumor tissues, where they can exert a direct or indirect anti-tumor activity.

Bronchoalveolar lavage fluid reveals factors contributing to the efficacy of PD-1 blockade in lung cancer

Bronchoalveolar lavage is commonly performed to assess inflammation and identify responsible pathogens in lung diseases. Findings from bronchoalveolar lavage might be used to evaluate the immune profile of the lung tumor microenvironment (TME). To investigate whether bronchoalveolar lavage fluid (BALF) analysis can help identify patients with non–small cell lung cancer (NSCLC) who respond to immune checkpoint inhibitors (ICIs), BALF and blood were prospectively collected before initiating nivolumab. The secreted molecules, microbiome, and cellular profiles based on BALF and blood analysis of 12 patients were compared with regard to therapeutic effect. Compared with ICI nonresponders, responders showed significantly higher CXCL9 levels and a greater diversity of the lung microbiome profile in BALF, along with a greater frequency of the CD56⁺ subset in blood T cells, whereas no significant difference in PD-L1 expression was found in tumor cells. Antibiotic treatment in a preclinical lung cancer model significantly decreased CXCL9 in the lung TME, resulting in reduced sensitivity to anti–PD-1 antibody, which was reversed by CXCL9 induction in tumor cells. Thus, CXCL9 might be associated with the lung TME microbiome, and the balance of CXCL9 and lung TME microbiome could contribute to nivolumab sensitivity in patients with NSCLC. BALF analysis can help predict the efficacy of ICIs when performed along with currently approved examinations.

Impact of the use of antibiotics on the clinical response to immune checkpoint inhibitors in patients with non-small cell lung cancer

OBJECTIVE

Recent research suggests that the use of antibiotics could reduce the efficacy of checkpoint inhibitors, in addition to other well-known factors. It could be due to gut microbiota modification, which impact over the immune system response. However, the information available so far is contradictory. The objective of this research was to clarify whether antibiotic use influences efficacy of checkpoint inhibitors treatments in non-small cell lung cancer patients in clinical practice.

METHODS

Therefore, a retrospective observational study was designed. Use of antibiotics among patients treated with atezolizumab, pembrolizumab or nivolumab was assessed within 2 months of checkpoint inhibitors treatments initiation.

RESULTS

A total of 140 patients were included, mostly men, with good performance status (ECOG 0-1), all of them previously treated with chemotherapy. An antibiotic prescription was identified in 31% of these patients, mainly fluoroquinolones or beta-lactams. The most frequent indication was respiratory infection. Both progression-free survival and overall survival were lower for patients treated with anti-infective drugs, although this difference was not statistically significant.

CONCLUSIONS

More studies are needed to draw conclusions about the impact of antibiotics on the efficacy of immunotherapy.

Human Gut Microbiota in Health and Selected Cancers

The majority of the epithelial surfaces of our body, and the digestive tract, respiratory and urogenital systems, are colonized by a vast number of bacteria, archaea, fungi, protozoans, and viruses. These microbiota, particularly those of the intestines, play an important, beneficial role in digestion, metabolism, and the synthesis of vitamins. Their metabolites stimulate cytokine production by the human host, which are used against potential pathogens. The composition of the microbiota is influenced by several internal and external factors, including diet, age, disease, and lifestyle. Such changes, called dysbiosis, may be involved in the development of various conditions, such as metabolic diseases, including metabolic syndrome, type 2 diabetes mellitus, Hashimoto's thyroidis and Graves' disease; they can also play a role in nervous system disturbances, such as multiple sclerosis, Alzheimer's disease, Parkinson's disease, and depression. An association has also been found between gut microbiota dysbiosis and cancer. Our health is closely associated with the state of our microbiota, and their homeostasis. The aim of this review is to describe the associations between human gut microbiota and cancer, and examine the potential role of gut microbiota in anticancer therapy.

Blood microbiome is associated with changes in portal hypertension after successful direct-acting antiviral therapy in patients with HCV-related cirrhosis

BACKGROUND

Patients with a significant decrease in hepatic venous pressure gradient (HVPG) have a considerable reduction of liver complications and higher survival after HCV eradication.

OBJECTIVES

To evaluate the association between the baseline blood microbiome and the changes in HVPG after successful direct-acting antiviral (DAA) therapy in patients with HCV-related cirrhosis.

METHODS

We performed a prospective study in 32 cirrhotic patients (21 HIV positive) with clinically significant portal hypertension (HVPG ≥10 mmHg). Patients were assessed at baseline and 48 weeks after HCV treatment completion. The clinical endpoint was a decrease in HVPG of ≥20% or HVPG <12 mmHg at the end of follow-up. Bacterial 16S ribosomal DNA was sequenced using MiSeq Illumina technology, inflammatory plasma biomarkers were investigated using ProcartaPlex immunoassays and the metabolome was investigated using GC-MS.

RESULTS

During the follow-up, 47% of patients reached the clinical endpoint. At baseline, those patients had a higher relative abundance of Corynebacteriales and Diplorickettsiales order, Diplorickettsiaceae family, Corynebacterium and Aquicella genus and Undibacterium parvum species organisms and a lower relative abundance of Oceanospirillales and Rhodospirillales order, Halomonadaceae family and Massilia genus organisms compared with those who did not achieve the clinical endpoint according to the LEfSe algorithm. Corynebacteriales and Massilia were consistently found within the 10 bacterial taxa with the highest differential abundance between groups. Additionally, the relative abundance of the Corynebacteriales order was inversely correlated with IFN-γ, IL-17A and TNF-α levels and the Massilia genus with glycerol and lauric acid.

CONCLUSIONS

Baseline-specific bacterial taxa are related to an HVPG decrease in patients with HCV-related cirrhosis after successful DAA therapy.

Clinical Effectiveness of Immune Checkpoint Inhibitors in Non-Small-Cell Lung Cancer with a Poor Performance Status

Immune checkpoint inhibitors (ICIs) are standard treatments for patients with lung cancer. PD-1/PD-L1 or CTLA4 antibodies are chosen as the first-line therapy, contributing to the long-term survival and tolerability. Unlike molecular targeting agents, such as gefitinib, lung cancer patients with a poor performance status (PS) display unsatisfactory clinical improvements after ICI treatment. Several previous reports also demonstrated that the PS is identified as one of the most probable prognostic factors for predicting poor outcomes after ICI treatment. However, first-line pembrolizumab seemed to be effective for lung cancer patients with a PS of 2 if PD-L1 expression was greater than 50%. Currently, the induction of ICIs in patients with lung cancer with a poor PS is controversial. These problems are discussed in this review.

Potential Implications of Citrulline and Quercetin on Gut Functioning of Monogastric Animals and Humans: A Comprehensive Review

The importance of gut health in animal welfare and wellbeing is undisputable. The intestinal microbiota plays an essential role in the metabolic, nutritional, physiological, and immunological processes of animals. Therefore, the rapid development of dietary supplements to improve gut functions and homeostasis is imminent. Recent studies have uncovered the beneficial effects of dietary supplements on the immune response, microbiota, gut homeostasis, and intestinal health. The application of citrulline (a functional gut biomarker) and quercetin (a known potent flavonoid) to promote gut functions has gained considerable interest as both bioactive substances possess anti-inflammatory, anti-oxidative, and immunomodulatory properties. Research has demonstrated that both citrulline and quercetin can mediate gut activities by combating disruptions to the intestinal integrity and alterations to the gut microbiota. In addition, citrulline and quercetin play crucial roles in maintaining intestinal immune tolerance and gut health. However, the synergistic benefits which these dietary supplements (citrulline and quercetin) may afford to simultaneously promote gut functions remain to be explored. Therefore, this review summarizes the modulatory effects of citrulline and quercetin on the intestinal integrity and gut microbiota, and further expounds on their potential synergistic roles to attenuate intestinal inflammation and promote gut health.

Liquid Biopsy Biomarkers for Immunotherapy in Non-Small Cell Lung Carcinoma: Lessons Learned and the Road Ahead

Over the recent years, advances in the development of anti-cancer treatments, particularly the implementation of ICIs (immune checkpoint inhibitors), have resulted in increased survival rates in NSCLC (non-small cell lung cancer) patients. However, a significant proportion of patients does not seem respond to immunotherapy, and some individuals even develop secondary resistance to treatment. Therefore, it is imperative to correctly identify the patients that will benefit from ICI therapy in order to tailor therapeutic options in an individualised setting, ultimately benefitting both the patient and the health system. Many different biomarkers have been explored to correctly stratify patients and predict response to immunotherapy, but liquid biopsy approaches have recently arisen as an interesting opportunity to predict and monitor treatment response due to their logistic accessibility. This review summarises the current data and efforts in the field of ICI response biomarkers in NSCLC patients and highlights advantages and limitations as we discuss the road to clinical implementation.

Blood microbiota diversity determines response of advanced colorectal cancer to chemotherapy combined with adoptive T cell immunotherapy

Human microbiota influence the response of malignancies to treatment with immune checkpoint blockade; however, their impact on other forms of immunotherapy is poorly understood. This study explored the effect of blood microbiota on clinical efficacy, represented by progression-free survival (PFS) and overall survival (OS), of combined chemotherapy and adoptive cellular therapy (ACT) in advanced colon cancer patients. Plasma was collected from colorectal cancer patients (CRC) treated with either chemotherapy alone (oxaliplatin and capecitabine) (XELOX CT alone group, n = 19), or ACT with a mixed dendritic cell/cytokine-induced killer cell product (DC-CIK) + XELOX (ICT group, n = 20). Circulating microbiota analysis was performed by PCR amplification and next-generation sequencing of variable regions V3~V4 of bacterial 16S rRNA genes. The association of the blood microbial diversity with clinical response to the therapy as measured by RECIST1.1 and OS was evaluated. The baseline Chao index of blood microbial diversity predicted prolonged PFS and OS of DC/CIK immunotherapy. More diverse blood microbiota that included Bifidobacterium, Lactobacillus, and Enterococcus were identified among responders to DC/CIK compared with non-responders. The plasma bacterial DNA copy number is inversely correlated with the CD3-/CD16+/CD56+ NK cells in circulation and decreased following DC-CIK; however, the Chao index of plasma microbiota significantly increased after administration of the DC-CIK product and this subsequent change was correlated with the number of CD3-/CD16+/CD56+ and CD8+/CD28+ cells infused. The diversity of the blood microbiome is a promising predictive marker for clinical responses to chemotherapy combined with DC-CIK. Cellular immunotherapy can affect the plasma microbiota's diversity in a manner favorable to clinical responses.

Emerging Evidence of the Gut Microbiome in Chemotherapy: A Clinical Review

Increasing evidence suggests that the gut microbiome is associated with both cancer chemotherapy (CTX) outcomes and adverse events (AEs). This review examines the relationship between the gut microbiome and CTX as well as the impact of CTX on the gut microbiome. A literature search was conducted in electronic databases Medline, PubMed and ScienceDirect, with searches for "cancer" and "chemotherapy" and "microbiome/microbiota". The relevant literature was selected for use in this article. Seventeen studies were selected on participants with colorectal cancer (CRC; n=5), Acute Myeloid Leukemia (AML; n=3), Non-Hodgkin's lymphoma (n=2), breast cancer (BCa; n=1), lung cancer (n=1), ovarian cancer (n=1), liver cancer (n=1), and various other types of cancers (n=3). Seven studies assessed the relationship between the gut microbiome and CTX with faecal samples collected prior to (n=3) and following CTX (n=4) showing that the gut microbiome is associated with both CTX efficacy and toxicity. Ten other prospective studies assessed the impact of CTX during treatment and found that CTX modulates the gut microbiome of people with cancer and that dysbiosis induced by the CTX is related to AEs. CTX adversely impacts the gut microbiome, inducing dysbiosis and is associated with CTX outcomes and AEs. Current evidence provides insights into the gut microbiome for clinicians, cancer survivors and the general public. More research is required to better understand and modify the impact of CTX on the gut microbiome.

State of the art: the role of citrulline as biomarker in patients with chemotherapy- or graft-versus-host-disease-induced mucositis

PURPOSE OF REVIEW

Serum or plasma citrulline levels are used as biomarker for a broad spectrum of intestinal functions. During high-dose chemotherapy, citrulline levels are decreased due to mucositis, a common side effect of chemotherapy. This may decrease intestinal function and result in diarrhea. In this review, most recent studies investigating citrulline as biomarker for intestinal function are discussed, with focus on patients with oncological diseases, specifically hematological malignancies with chemotherapy- or Graft-versus-Host-disease (GVHD)-induced mucositis.

RECENT FINDINGS

Citrulline has recently been widely studied in relation to intestinal function and various clinical conditions. It seems therefore a promising noninvasive biomarker in clinical practice for more than intestinal function alone. The association between citrulline levels and intestinal function in patients with hematological malignancies, with or without mucositis remains unclear, as no other parameters of intestinal function for this purpose were assessed.

SUMMARY

In conclusion, citrulline seems to be a promising noninvasive biomarker for various intestinal conditions in general, and potentially for intestinal function in patients with chemotherapy- or GVHD-induced mucositis. It is unclear from recent literature whether high fecal volume or diarrhea as side effect, results in impaired intestinal function and severe malabsorption and if citrulline biomarkers can be useful to detect this.

Soluble Biomarkers with Prognostic and Predictive Value in Advanced Non-Small Cell Lung Cancer Treated with Immunotherapy

Numerous targeted therapies have been evaluated for the treatment of non-small cell lung cancer (NSCLC). To date, however, only a few agents have shown promising results. Recent advances in cancer immunotherapy, most notably immune checkpoint inhibitors (ICI), have transformed the treatment scenario for these patients. Although some patients respond well to ICIs, many patients do not benefit from ICIs, leading to disease progression and/or immune-related adverse events. New biomarkers capable of reliably predicting response to ICIs are urgently needed to improve patient selection. Currently available biomarkers-including programmed death protein 1 (PD-1) and its ligand (PD-L1), and tumor mutational burden (TMB)-have major limitations. At present, no well-validated, reliable biomarkers are available. Ideally, these biomarkers would be obtained through less invasive methods such as plasma determination or liquid biopsy. In the present review, we describe recent advances in the development of novel soluble biomarkers (e.g., circulating immune cells, TMB, circulating tumor cells, circulating tumor DNA, soluble factor PD-L1, tumor necrosis factor, etc.) for patients with NSCLC treated with ICIs. We also describe the potential use of these biomarkers as prognostic indicators of treatment response and toxicity.

Citrulline, Biomarker of Enterocyte Functional Mass and Dietary Supplement. Metabolism, Transport, and Current Evidence for Clinical Use

L-Citrulline is a non-essential but still important amino acid that is released from enterocytes. Because plasma levels are reduced in case of impaired intestinal function, it has become a biomarker to monitor intestinal integrity. Moreover, oxidative stress induces protein citrullination, and antibodies against anti-citrullinated proteins are useful to monitor rheumatoid diseases. Citrullinated histones, however, may even predict a worse outcome in cancer patients. Supplementation of citrulline is better tolerated compared to arginine and might be useful to slightly improve muscle strength or protein balance. The following article shall provide an overview of L-citrulline properties and functions, as well as the current evidence for its use as a biomarker or as a therapeutic supplement.

Gut microbiota-mediated immunomodulation in tumor

Tumor immunity consists of various types of cells, which serve an important role in antitumor therapy. The gastrointestinal tract is colonized by trillions of microorganisms, which form the gut microbiota. In addition to pathogen defense and maintaining the intestinal ecosystem, gut microbiota also plays a pivotal role in various physiological processes. Recently, the association between these symbionts and cancer, ranging from oncogenesis and cancer progression to resistance or sensitivity to antitumor therapies, has attracted much attention. Metagenome analysis revealed a significant difference between the gut microbial composition of cancer patients and healthy individuals. Moreover, modulation of microbiome could improve therapeutic response to immune checkpoint inhibitors (ICIs). These findings suggest that microbiome is involved in cancer pathogenesis and progression through regulation of tumor immunosurveillance, although the exact mechanisms remain largely unknown. This review focuses on the interaction between the microbiome and tumor immunity, with in-depth discussion regarding the therapeutic potential of modulating gut microbiota in ICIs. Further investigations are warranted before gut microbiota can be introduced into clinical practice.

Diet, Microbiome, and Cancer Immunotherapy-A Comprehensive Review

The immune system plays a key role in cancer suppression. Immunotherapy is widely used as a treatment method in patients with various types of cancer. Immune checkpoint blockade using antibodies, such as anti-PD-1, anti-PD-L1, and anti-CTLA-4, is currently gaining popularity. A systematic literature search was executed, and all available data was summarized. This review shows that specific dietary patterns (such as, e.g., animal-based, vegetarian, or Mediterranean diet) alter the gut microbiome's composition. An appropriate intestinal microbiota structure might modulate the function of human immune system, which affects the bodily anti-cancer response. This paper shows also that specific bacteria species inhabiting the gastrointestinal tract can have a beneficial influence on the efficacy of immunotherapy. Antibiotics weaken gut bacteria and worsen the immune checkpoint blockers' efficacy, whereas a faecal microbiota transplant or probiotics supplementation may help restore bacterial balance in the intestine. Other factors (like vitamins, glucose, or BMI) change the cancer treatment response, as well. This review demonstrates that there is a strong association between one's diet, gut microbiome composition, and the outcome of immunotherapy. However, further investigation on this subject is required.

Effect of antibiotic use on the efficacy of nivolumab in the treatment of advanced/metastatic non-small cell lung cancer: A meta-analysis

This study evaluates the impact of the use of antibiotics on the effectiveness of nivolumab in the treatment of advanced/metastatic non-small cell lung cancer (NSCLC). A literature search was conducted in various electronic databases to identify studies, which evaluated the impact of antibiotic use on the survival of patients with advanced/metastatic NSCLC who have been treated with nivolumab. Six studies, comprising a total of 787 patients with 37.2% females and of age range 30–90 years, were included in the study. A lack of smoking history was reported in 14.4% of the patients. A meta-analysis was conducted in 678 and 713 patients for PFS and OS, respectively. The pooled HR was 1.95 (95% CI: 1.13–3.37, P = 0.016) for PFS and 2.70 (95% CI: 1.81–4.02, P < 0.001) for OS. Among patients exposed to antibiotics, the median PFS and OS were reduced by 1.6 months (95% CI: 1.5–1.7) and 8.8 months (95% CI: 8.5–9.1), respectively. Our study indicates that, among patients with advanced/metastatic NSCLC, the use of antibiotics with nivolumab led to a decrease in the median OS by more than 8 months. Studying the mechanism of the effect of antibiotics on the efficacy of nivolumab in patients with NSCLC should also be prioritized.

Recognizing Prognostic and Predictive Biomarkers in the Treatment of Non-Small Cell Lung Cancer (NSCLC) with Immune Checkpoint Inhibitors (ICIs)

Immunotherapy plays a central role in the treatment of NSCLC and biomarkers predicting response to ICIs are valuable therapeutic tools. Programmed death-ligand 1 (PD-L1) immunohistochemistry (IHC) is integral in therapy selection as its positive predictive nature to ICIs in the metastatic setting is well documented. Tumor mutational burden (TMB) has undergone much study and, while results are somewhat mixed, there is evidence for its positive predictive value with ICI use. Additional markers such as tumor-infiltrating lymphocytes (TILs), gene expression profiling (GEP), mismatch repair (MMR) and microsatellite instability (MSI), somatic mutations, neutrophil to leukocyte ratio (NLR), smoking history, medication history, and immune-related adverse event (irAE) development can further guide clinicians.

Use of antibiotics is associated with worse clinical outcomes in patients with cancer treated with immune checkpoint inhibitors: A systematic review and meta-analysis

OBJECTIVES

Observational and experimental studies suggest that the use of antibiotics close to administration of immune checkpoint inhibitors (ICI) can have a negative effect on tumour response and patient survival, due to microbiome dysbiosis and the resultant suppression of host immune response against neoplastic cells.

METHODS

A systematic search of PUBMED and EMBASE was undertaken for studies published between 1 January 2017 and 1 June 2020, evaluating the association between the use of antibiotics and clinical outcomes in patients with cancer treated with ICIs. A meta-analysis of the association between the use of antibiotics and clinical outcomes was also performed.

RESULTS

Forty-eight studies met the inclusion criteria (12,794 patients). Use of antibiotics was associated with shorter overall survival [hazard ratio (HR) 1.88, 95% confidence interval (CI) 1.59-2.22; adjusted HR 1.87, 95% CI 1.55-2.25] and progression-free survival (HR 1.52, 95% CI 1.36-1.70; adjusted HR 1.93, 95% CI 1.59-2.36), decreased response rate [odds ratio (OR) 0.54, 95% CI 0.34-0.86] and more disease progression (OR 2.00, 95% CI 1.27-3.14). The negative association between the use of antibiotics and progression-free survival was stronger in patients with renal cell carcinoma or melanoma compared with lung cancer. Only antibiotic administration >1 month prior to ICI initiation was associated with increased disease progression. Heterogeneity was substantial for all outcomes.

CONCLUSIONS

Recent use of antibiotics in patients with cancer treated with ICIs was associated with worse clinical outcomes. Such patients may benefit from dedicated antimicrobial stewardship programmes.

Impact of Antibiotic Therapy and Metabolic Parameters in Non-Small Cell Lung Cancer Patients Receiving Checkpoint Inhibitors

Introduction: In the current study, we aimed to assess the impact of antibiotics (ATB) and metabolic parameters on clinical outcome of non-small cell lung carcinoma (NSCLC) patients treated with immune checkpoint inhibitors (ICI). Methods: Data from fifty NSCLC patients referred for ICI between December 2015 and May 2019 were analyzed. All patients underwent 18F-fluorodeoxyglucose positron emission tomography computed tomography (18F-FDG PET/CT) and contrast-enhanced CT at baseline and for response assessment after 6–8 weeks. Patients who received ATB within 1 month before or after the first dose of ICI were compared with those who did not. Response assessment according to iRECIST and EORTC was evaluated, as well as progression-free survival (PFS) and overall survival (OS). For semi-quantitative parameters, we computed metabolic tumor volume (MTV), total lesion glycolysis (TLG) and their variations (∆). Results: Twenty NSCLC cases of 50 (40%) had received ATB. Patients receiving ATB had a higher number of metastases (p = 0.046), and were associated with an elevated tumor burden, expressed by TLG (687 vs. 235.3, p = 0.007) and MTV (125.6 vs. 40.6, p = 0.002), compared to no-ATB patients. According to iRECIST, progressive disease rate was significantly higher for ATB group (64.7% vs. 27.6%, p = 0.029). Likewise, PFS was shorter for ATB compared to no-ATB (median 4.1 vs. 12.4 months, p = 0.004), while no difference for OS was detected. On multivariate analysis, the effect of ATB remained significant for poor PFS along with performance status (ECOG ≥ 1), and ∆SUVmax. Conclusions: ATB therapy seems to be associated with a worse treatment response, PFS, and higher metabolic tumor burden in NSCLC patients treated with ICI.