The Different Functional Distribution of "Not Effector" T Cells (Treg/Tnull) in Colorectal Cancer

Generation of colon cancer-derived tumor-infiltrating T cells (TILs) for adoptive cell therapy

Adoptive cell therapy (ACT) using specific immune cells and stem cells has emerged as a promising treatment option that could complement traditional cancer therapies in the future. In particular, tumor-infiltrating lymphocytes (TILs) have been shown to be effective against solid tumors in various clinical trials. Despite the enormous disease burden and large number of premature deaths caused by colorectal cancer (CRC), studies on TILs isolated from tumor tissue of patients with CRC are still rare. To date, studies on ACT often lack controlled and comparable expansion processes as well as selected ACT-relevant T-cell populations. We describe a procedure for generating patient-specific TILs, which are prerequisites for clinical trials of ACT in CRC. The manufacturing and characteristics of these TILs differ in important modalities from TILs commonly used for this therapeutic approach. Tumor tissue samples were obtained from 12 patients undergoing surgery for primary CRC, predominantly with low microsatellite instability (pMMR-MSI-L). Tumors in the resected specimens were examined pathologically, and an approved volume of tumor tissue was transferred to a disposable perfusion bioreactor. Tissue samples were subjected to an automatically controlled and highly reproducible cultivation process in a GMP-conform, closed perfusion bioreactor system using starting medium containing interleukin-2 and interleukin-12. Outgrowth of TIL from tissue samples was initiated by short-term supplementation with a specific activation cocktail. During subsequent expansion, TILs were grown in interleukin-2-enriched medium. Expansion of TILs in a low-scaled, two-phase process in the Zellwerk ZRP bioreactor under hyperoxic conditions resulted in a number of approximately 2 × 10⁹ cells. The expanded TILs consisted mainly (73%) of the ACT-relevant CD3⁺/CD8⁺ effector memory phenotype (CD45RO⁺/CCR7^-). TILs harvested under these conditions exhibited high functional potential, which was confirmed upon nonspecific stimulation (interferon-γ, tumor necrosis factor-α cytokine assay).

A comparative study of carbonic anhydrase activity in lymphocytes from colorectal cancer tissues and adjacent healthy counterparts

Several carbonic anhydrase (CA, EC 4.2.1.1) isoforms play an essential role in processes connected to tumorigenesis, as they efficiently accelerate the hydration of carbon dioxide to bicarbonate and proton. In this context, examples are CA IX and CA XII, which were proved to be upregulated in many solid malignancies. On the other hand, cancer and the immune system are inextricably linked, and targeting the immune checkpoints recently was shown to efficiently improve the treatment of malignancies. In this study, we have investigated the expression of CA isoforms in tumour-infiltrating lymphocytes (TILs) that, according to the immunosurveillance theory, were suggested to have a crucial role in the development of colorectal cancer (CRC). T lymphocytes isolated from healthy surrounding mucosa showed a higher CA activity compared to those present in tumour and peripheral blood in the same patients. CA I and II were confirmed as enzyme isoforms involved in the process, as determined by proteomic analysis of corresponding TIL samples. These preliminary findings suggest a dysregulation of the local immune response in the CRC tissues and a loss of effective anticancer mechanisms mediated by CAs therein.

Characterization of the “gut microbiota-immunity axis” and microbial lipid metabolites in atrophic and potential celiac disease

Introduction

Potential celiac disease (pCD) is characterized by genetic predisposition, positive anti-endomysial and anti-tissue transglutaminase antibodies, but a normal or almost normal jejunal mucosa (e.g., minor histological abnormalities without villous atrophy). To gain further insights into basic mechanisms involved in the development of intestinal villous atrophy, we evaluated and compared the microbial, lipid, and immunological signatures of pCD and atrophic CD (aCD).

Materials and methods

This study included 17 aCD patients, 10 pCD patients, and 12 healthy controls (HC). Serum samples from all participants were collected to analyze free fatty acids (FFAs). Duodenal mucosa samples of aCD and pCD patients were taken to evaluate histology, tissue microbiota composition, and mucosal immune response.

Results

We found no significant differences in the mucosa-associated microbiota composition of pCD and aCD patients. On the other hand, in pCD patients, the overall abundance of serum FFAs showed relevant and significant differences in comparison with aCD patients and HC. In detail, compared to HC, pCD patients displayed higher levels of propionic, butyric, valeric, 2-ethylhexanoic, tetradecanoic, hexadecanoic, and octadecanoic acids. Instead, aCD patients showed increased levels of propionic, isohexanoic, and 2-ethylhexanoic acids, and a lower abundance of isovaleric and 2-methylbutyricacids when compared to HC. In addition, compared to aCD patients, pCD patients showed a higher abundance of isobutyric and octadecanoic acid. Finally, the immunological analysis of duodenal biopsy revealed a lower percentage of CD4⁺ T lymphocytes in pCD infiltrate compared to that observed in aCD patients. The functional characterization of T cells documented a pro-inflammatory immune response in both aCD and pCD patients, but the pCD patients showed a higher percentage of Th0/Th17 and a lower percentage of Th1/Th17.

Conclusion

The results of the present study show, for the first time, that the duodenal microbiota of patients with pCD does not differ substantially from that of aCD; however, serum FFAs and local T cells displayed a distinctive profile between pCD, aCD, and HC. In conclusion, our result may help to shed new light on the “gut microbiota-immunity axis,” lipid metabolites, and duodenal immune response in overt CD and pCD patients, opening new paradigms in understanding the pathogenesis behind CD progression.

Gut Microbiota and Associated Mucosal Immune Response in Eosinophilic Granulomatosis with Polyangiitis (EGPA)

Eosinophilic granulomatosis with polyangiitis (EGPA) is an anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis. A genome-wide association study showed a correlation between ANCA-negative EGPA and variants of genes encoding proteins with intestinal barrier functions, suggesting that modifications of the mucosal layer and consequent gut dysbiosis might be involved in EGPA pathogenesis. Here, we characterized the gut microbiota (GM) composition and the intestinal immune response in a cohort of EGPA patients. Faeces from 29 patients and 9 unrelated healthy cohabitants were collected, and GM and derived metabolites’ composition were compared. Seven intestinal biopsies from EGPA patients with gastrointestinal manifestations were analysed to assess the T-cell distribution and its correlation with GM and EGPA clinical and laboratory features. No significant differences in GM composition, nor in the total amount of faecal metabolites, emerged between patients and controls. Nevertheless, differences in bacterial taxa abundances and compositional GM-derived metabolites profile were observed. Notably, an enrichment of potential pathobionts (Enterobacteriacee and Streptococcaceae) was found in EGPA, particularly in patients with active disease, while lower levels were found in patients on immunosuppression, compared with non-immunosuppressed ones. Significantly lower amounts of hexanoic acid were found in patients, compared to controls. The analysis of the immune response in the gut mucosa revealed a high frequency of IFN-γ/IL-17-producing T lymphocytes, and a positive correlation between EGPA disease activity and intestinal T-cell levels. Our data suggest that an enrichment in potential intestinal pathobionts might drive an imbalanced inflammatory response in EGPA.

Gut mucosal microbiota profiles linked to colorectal cancer recurrence

BACKGROUND

Emerging evidence links gut microbiota to various human diseases including colorectal cancer (CRC) initiation and development. However, gut microbiota profiles associated with CRC recurrence and patient prognosis are not completely understood yet, especially in a Chinese cohort.

AIM

To investigate the relationship between gut mucosal microbiota profiles and CRC recurrence and patient prognosis.

METHODS

We obtained the composition and structure of gut microbiota collected from 75 patients diagnosed with CRC and 26 healthy controls. The patients were followed up by regular examination to determine whether tumors recurred. Triplet-paired samples from on-tumor, adjacent-tumor and off-tumor sites of patients diagnosed with/without CRC recurrence were analyzed to assess spatial-specific patterns of gut mucosal microbiota by 16S ribosomal RNA sequencing. Next, we carried out bioinformatic analyses, Kaplan-Meier survival analyses and Cox regression analyses to determine the relationship between gut mucosal microbiota profiles and CRC recurrence and patient prognosis.

RESULTS

We observed spatial-specific patterns of gut mucosal microbiota profiles linked to CRC recurrence and patient prognosis. A total of 17 bacterial genera/families were identified as potential biomarkers for CRC recurrence and patient prognosis, including Anaerotruncus, Bacteroidales, Coriobacteriaceae, Dialister, Eubacterium, Fusobacterium, Filifactor, Gemella, Haemophilus, Mogibacteriazeae, Pyramidobacter, Parvimonas, Porphyromonadaceae, Slackia, Schwartzia, TG5 and Treponema.

CONCLUSION

Our work suggests that intestinal microbiota can serve as biomarkers to predict the risk of CRC recurrence and patient death.

Fusobacterium nucleatum promotes liver metastasis in colorectal cancer by regulating the hepatic immune niche and altering gut microbiota

Liver metastasis is the major cause of death in colorectal cancer (CRC) patients. Nevertheless, the underlying mechanisms remain unknown. Gut microbiota intricately affect the initiation and progression of CRC by instigating immune response through the secretion of pro-inflammatory cytokines. In this study, we investigated the contribution of Fusobacterium nucleatum (F.nucleatum) to the microbiota-liver axis of CRC in mice, focusing on the correlation between liver immunity and gut microbiota alterations. When F. nucleatum was orally administered to mice, CRC liver metastasis was evidently exaggerated and accompanied by noticeable deleterious effects on body weight, cecum weight, and overall survival time. Further evaluation of the immune response and cytokine profiles revealed a substantial increase in the levels of pro-inflammatory cytokines such as IL6, IL12, IL9, IL17A, CXCL1, MCP-1, TNF-α, and IFN-γ in the plasma of mice treated with F. nucleatum as compared to that in the untreated control mice. Besides, hepatic immune response was also modulated by recruitment of myeloid-derived suppressor cells, reduction in the infiltration of natural killer (NK) and T helper-17 (Th17) cells, as well as increase in regulatory T cell accumulation in the liver. Additionally, sustained F. nucleatum exposure abridged the murine gut microbiota diversity, inducing an imbalanced and restructured intestinal microflora. In particular, the abundance of CRC-promoting bacteria such as Enterococcus and Escherichia/Shigella was evidently elevated post F. nucleatum treatment. Thus, our findings suggest that F. nucleatum might be an important factor involved in promoting CRC liver metastasis by triggering of liver immunity through the regulation of gut microbiota structure and composition.

Systemic Interleukins' Profile in Early and Advanced Colorectal Cancer

Tumor microenvironment (TME) is characterized by mutual interactions of the tumor, stromal and immune cells. Early and advanced colorectal tumors differ in structure and present altered serum cytokine levels. Mutual crosstalk among TME infiltrating cells may shift the balance into immune suppressive or pro-inflammatory, antitumor response this way influencing patients' prognosis. Cancer-related inflammation affects all the body and this way, the systemic level of cytokines could reflect TME processes. Despite numerous studies, it is still not known how systemic cytokines levels change during colorectal cancer (CRC) tumor development. Better understanding tumor microenvironment processes could help in planning therapeutic interventions and more accurate patient prognosis. To contribute to the comprehension of these processes within TME, we reviewed cytokines levels from clinical trials in early and advanced colorectal cancer. Presented data were analyzed in the context of experimental studies and studies analyzing tumor infiltration with immune cells. The review summarizes clinical data of cytokines secreted by tumor microenvironment cells: lymphocytes T helper 1 (Th1), lymphocytes T helper 2 (Th2), lymphocytes T helper 17 (Th17), regulatory T cells (Treg cells), regulatory T cells (Breg cells), M1/M2 macrophages, N1/N2 neutrophils, myeloid-derived suppressor cells (MDSC), dendritic cells (DC), innate lymphoid cells (ILC) natural killer (NK) cells and tumor cells.

Fecal metabolomic profiles: A comparative study of patients with colorectal cancer vs adenomatous polyps

BACKGROUND

Colorectal cancer (CRC), the third most common cause of death in both males and females worldwide, shows a positive response to therapy and usually a better prognosis when detected at an early stage. However, the survival rate declines when the diagnosis is late and the tumor spreads to other organs. Currently, the measures widely used in the clinic are fecal occult blood test and evaluation of serum tumor markers, but the lack of sensitivity and specificity of these markers restricts their use for CRC diagnosis. Due to its high sensitivity and precision, colonoscopy is currently the gold-standard screening technique for CRC, but it is a costly and invasive procedure. Therefore, the implementation of custom-made methodologies including those with minimal invasiveness, protection, and reproducibility is highly desirable. With regard to other screening methods, the screening of fecal samples has several benefits, and metabolomics is a successful method to classify the metabolite shift in living systems as a reaction to pathophysiological influences, genetic modifications, and environmental factors.

AIM

To characterize the variation groups and potentially recognize some diagnostic markers, we compared with healthy controls (HCs) the fecal nuclear magnetic resonance (NMR) metabolomic profiles of patients with CRC or adenomatous polyposis (AP).

METHODS

Proton nuclear magnetic resonance spectroscopy was used in combination with multivariate and univariate statistical approaches, to define the fecal metabolic profiles of 32 CRC patients, 16 AP patients, and 38 HCs well matched in age, sex, and body mass index.

RESULTS

NMR metabolomic analyses revealed that fecal sample profiles differed among CRC patients, AP patients, and HCs, and some discriminatory metabolites including acetate, butyrate, propionate, 3-hydroxyphenylacetic acid, valine, tyrosine and leucine were identified.

CONCLUSION

In conclusion, we are confident that our data can be a forerunner for future studies on CRC management, especially the diagnosis and evaluation of the effectiveness of treatments.

Ex vivo modelling of PD-1/PD-L1 immune checkpoint blockade under acute, chronic, and exhaustion-like conditions of T-cell stimulation

Blockade of PD-1/PD-L1 interactions is proving an exciting, durable therapeutic modality in a range of cancers whereby T cells are released from checkpoint inhibition to revive their inherent anti-tumour activity. Here we have studied various ways to model ex vivo T cell function in order to compare the impact of the clinically utilised anti-PD-1 antibody, pembrolizumab (Keytruda) on the activation of human T cells: focussing on the release of pro-inflammatory IFNγ and anti-inflammatory IL-10 to assess functionality. Firstly, we investigated the actions of pembrolizumab in an acute model of T-cell activation with either immature or mature allogeneic dendritic cells (DCs); pembrolizumab enhanced IFNγ and IL-10 release from purified CD4+ T-cells in the majority of donors with a bias towards pro-inflammatory cytokine release. Next, we modelled the impact of pembrolizumab in settings of more chronic T-cell activation. In a 7-day antigen-specific response to EBV peptides, the presence of pembrolizumab resulted in a relatively modest increase in both IFNγ and IL-10 release. Where pembrolizumab was assessed against long-term stimulated CD4+ cells that had up-regulated the exhaustion markers TIM-3 and PD-1, there was a highly effective enhancement of the otherwise exhausted response to allogeneic DCs with respect to IFNγ production. By contrast, the restoration of IL-10 production was considerably more limited. Finally, to assess a direct clinical relevance we investigated the consequence of PD-1/PD-L1 blockade in the disease setting of dissociated cells from lung and colon carcinomas responding to allogeneic DCs: here, pembrolizumab once more enhanced IFNγ production from the majority of tumour preparations whereas, again, the increase in IL-10 release was modest at best. In conclusion, we have shown that the contribution of PD-1-revealed by using a canonical blocking antibody to interrupt its interaction with PD-L1-to the production of an exemplar pro- and anti-inflammatory cytokine, respectively, depends in magnitude and ratio on the particular stimulation setting and activation status of the target T cell. We have identified a number of in vitro assays with response profiles that mimic features of dissociated cell populations from primary tumours thereby indicating these represent disease-relevant functional assays for the screening of immune checkpoint inhibitors in current and future development. Such in vitro assays may also support patient stratification of those likely to respond to immuno-oncology therapies in the wider population.

Significant and Conflicting Correlation of IL-9 With Prevotella and Bacteroides in Human Colorectal Cancer

Background and aim

Gut microbiota (GM) can support colorectal cancer (CRC) progression by modulating immune responses through the production of both immunostimulatory and/or immunosuppressive cytokines. The role of IL-9 is paradigmatic because it can either promote tumor progression in hematological malignancies or inhibit tumorigenesis in solid cancers. Therefore, we investigate the microbiota–immunity axis in healthy and tumor mucosa, focusing on the correlation between cytokine profile and GM signature.

Methods

In this observational study, we collected tumor (CRC) and healthy (CRC-S) mucosa samples from 45 CRC patients, who were undergoing surgery in 2018 at the Careggi University Hospital (Florence, Italy). First, we characterized the tissue infiltrating lymphocyte subset profile and the GM composition. Subsequently, we evaluated the CRC and CRC-S molecular inflammatory response and correlated this profile with GM composition, using Dirichlet multinomial regression.

Results

CRC samples displayed higher percentages of Th17, Th2, and Tregs. Moreover, CRC tissues showed significantly higher levels of MIP-1α, IL-1α, IL-1β, IL-2, IP-10, IL-6, IL-8, IL-17A, IFN-γ, TNF-α, MCP-1, P-selectin, and IL-9. Compared to CRC-S, CRC samples also showed significantly higher levels of the following genera: Fusobacteria, Proteobacteria, Fusobacterium, Ruminococcus2, and Ruminococcus. Finally, the abundance of Prevotella spp. in CRC samples negatively correlated with IL-17A and positively with IL-9. On the contrary, Bacteroides spp. presence negatively correlated with IL-9.

Conclusions

Our data consolidate antitumor immunity impairment and the presence of a distinct microbiota profile in the tumor microenvironment compared with the healthy mucosa counterpart. Relating the CRC cytokine profile with GM composition, we confirm the presence of bidirectional crosstalk between the immune response and the host’s commensal microorganisms. Indeed, we document, for the first time, that Prevotella spp. and Bacteroides spp. are, respectively, positively and negatively correlated with IL-9, whose role in CRC development is still under debate.

The Regulation of Intestinal Inflammation and Cancer Development by Type 2 Immune Responses

The gut is among the most complex organs of the human body. It has to exert several functions including food and water absorption while setting up an efficient barrier to the outside world. Dysfunction of the gut can be life-threatening. Diseases of the gastrointestinal tract such as inflammatory bowel disease, infections, or colorectal cancer, therefore, pose substantial challenges to clinical care. The intestinal epithelium plays an important role in intestinal disease development. It not only establishes an important barrier against the gut lumen but also constantly signals information about the gut lumen and its composition to immune cells in the bowel wall. Such signaling across the epithelial barrier also occurs in the other direction. Intestinal epithelial cells respond to cytokines and other mediators of immune cells in the lamina propria and shape the microbial community within the gut by producing various antimicrobial peptides. Thus, the epithelium can be considered as an interpreter between the microbiota and the mucosal immune system, safeguarding and moderating communication to the benefit of the host. Type 2 immune responses play important roles in immune-epithelial communication. They contribute to gut tissue homeostasis and protect the host against infections with helminths. However, they are also involved in pathogenic pathways in inflammatory bowel disease and colorectal cancer. The current review provides an overview of current concepts regarding type 2 immune responses in intestinal physiology and pathophysiology.

Resolving the Paradox of Colon Cancer Through the Integration of Genetics, Immunology, and the Microbiota

While colorectal cancers (CRC) are paradigmatic tumors invaded by effector memory lymphocytes, the mechanisms accounting for the relative resistance of MSI negative CRC to immunogenic cell death mediated by oxaliplatin and immune checkpoint inhibitors has remained an open conundrum. Here, we propose the viewpoint where its microenvironmental contexture could be explained -at least in part- by macroenvironmental cues constituted by the complex interplay between the epithelial barrier, its microbial ecosystem, and the local immune system. Taken together this dynamic ménage-à-trois offers novel coordinated actors of the humoral and cellular immune responses actionable to restore sensitivity to immune checkpoint inhibition. Solving this paradox involves breaking tolerance to crypt stem cells by inducing the immunogenic apoptosis of ileal cells in the context of an ileal microbiome shifted towards immunogenic bacteria using cytotoxicants. This manoeuver results in the elicitation of a productive Tfh and B cell dialogue in mesenteric lymph nodes culminating in tumor-specific memory CD8+ T cell responses sparing the normal epithelium.

Immune Landscape in Tumor Microenvironment: Implications for Biomarker Development and Immunotherapy

Integration of the tumor microenvironment as a fundamental part of the tumorigenic process has undoubtedly revolutionized our understanding of cancer biology. Increasing evidence indicates that neoplastic cells establish a dependency relationship with normal resident cells in the affected tissue and, furthermore, develop the ability to recruit new accessory cells that aid tumor development. In addition to normal stromal and tumor cells, this tumor ecosystem includes an infiltrated immune component that establishes complex interactions that have a critical effect during the natural history of the tumor. The process by which immune cells modulate tumor progression is known as immunoediting, a dynamic process that creates a selective pressure that finally leads to the generation of immune-resistant cells and the inability of the immune system to eradicate the tumor. In this context, the cellular and functional characterization of the immune compartment within the tumor microenvironment will help to understand tumor progression and, ultimately, will serve to create novel prognostic tools and improve patient stratification for cancer treatment. Here we review the impact of the immune system on tumor development, focusing particularly on its clinical implications and the current technologies used to analyze immune cell diversity within the tumor.

Metabolomics profile in gastrointestinal cancers: Update and future perspectives

Despite recent progress in diagnosis and therapy, gastrointestinal (GI) cancers remain one of the most important causes of death with a poor prognosis due to late diagnosis. Serum tumor markers and detection of occult blood in the stool are the current tests used in the clinic of GI cancers; however, these tests are not useful as diagnostic screening since they have low specificity and low sensitivity. Considering that one of the hallmarks of cancer is dysregulated metabolism and metabolomics is an optimal approach to illustrate the metabolic mechanisms that belong to living systems, is now clear that this -omics could open a new way to study cancer. In the last years, nuclear magnetic resonance (NMR) metabolomics has demonstrated to be an optimal approach for diseases' diagnosis nevertheless a few studies focus on the NMR capability to find new biomarkers for early diagnosis of GI cancers. For these reasons in this review, we will give an update on the status of NMR metabolomic studies for the diagnosis and development of GI cancers using biological fluids.

Phenotype molding of T cells in colorectal cancer by single-cell analysis

The majority of patients with microsatellite stable (MSS) colorectal cancer (CRC) do not benefit from the immunotherapies directed at rescuing T-cell functions. Therefore, complete understanding of T-cell phenotypes and functional status in the CRC microenvironment is desirable. Here, we applied single-cell mass cytometry to mold the T-cell phenotype in 18 patients with MSS CRC for better understanding of CRC as a systemic disease and to search for tumor-driven T-cell profile changes. We show interpatient and intrapatient phenotypic diversity of T-cell subsets. We revealed increased immunosuppressive/exhausted T-cell phenotypes at tumor lesions. CD8+ CD28- immunosenescent T cells with impaired proliferation capacity dominate the T-cell compartment. As per the transcriptome and quantitative real time-PCR analysis, the accumulation of immunosuppressive cells is driven by the tumor microenvironment. T-cell profiles are similar between patients at early and late stages, indicating that the immunosuppressive microenvironment is formulated early during CRC development. Mapping of T-cell infiltration and understanding of the mechanisms underlying their regulation may provide valuable information to boost the immune response in patients with MSS CRC.

The Role of the Immune Infiltrate in Distinct Cancer Types and Its Clinical Implications : Lymphocytic Infiltration in Colorectal Cancer

Colorectal cancer (CRC) represents a major public health challenges, with one of the highest incidences worldwide. The two affected anatomical sites in CRC, i.e. the colon and the rectum, share important underlying features, but often differ in terms of therapeutic management. Current guidelines for CRC define its clinical stratification according to classical, tumor cell-based and pathological parameters. Novel ground-breaking findings in the recent years revealed the prominent role of the immune system in shaping CRC development. This chapter provides a detailed overview of the main genomic and immune features driving (or hampering) CRC progression, with a focus on the main immune cells and factors shaping its evolution. Furthermore, we discuss how tumor-infiltrating immunity could be leveraged both for therapeutic and stratification purposes.

Interleukin-24 Regulates T Cell Activity in Patients With Colorectal Adenocarcinoma

Interleukin (IL)-24 plays a potential anti-tumor activity in colorectal cancer in a dose-dependent manner. However, the immunoregulatory role of IL-24 to peripheral and tumor-infiltrating T cell function in colorectal cancer was not fully elucidated. In this study, twenty-nine colorectal adenocarcinoma patients and fifteen healthy individuals were enrolled. IL-24 expression and IL-24 receptor (IL-20R1, IL-20R2, and IL-22R1) mRNA relative level was measured by ELISA and real-time PCR, respectively. CD4⁺ and CD8⁺ T cells were purified from peripheral bloods and cancer specimens, and were stimulated with low (10 ng/ml) and high (100 ng/ml) concentration of recombinant IL-24. CD4⁺ T cells activity was assessed by measurement of Th cell percentage, transcriptional factors, and cytokine production. CD8⁺ T cells activity was evaluated by investigation of cytotoxic molecules, target cell death, and interferon-γ (IFN-γ) secretion. IL-24 was decreasingly expressed in both peripheral bloods and cancer tissues in colorectal adenocarcinoma patients. However, IL-20R1 and IL-20R2 was comparable between healthy controls and colorectal adenocarcinoma patients. Low concentration of IL-24 suppressed CD4⁺ T cell proliferation. In contrast, high concentration of IL-24 not only promoted CD4⁺ T cell proliferation, but also enhanced CD4⁺ T cell activity, which mainly presented as up-regulation of Th1/Th17 frequency, T-bet/RORγt mRNA, and IFN-γ/IL-17 production but down-regulation of Treg percentage, FoxP3 mRNA, and IL-10/IL-35 secretion. Moreover, high concentration of IL-24 also increased perforin and granzyme B expression in CD8⁺ T cells, and elevated cytolytic and non-cytolytic activity of CD8⁺ T cells, which presented as induction of target cell death and elevation of IFN-γ expression. However, low concentration of IL-24 did not affect bioactivity of CD8⁺ T cells. The current data indicated that IL-24 might regulate T cell function in a dose-dependent manner. High-concentration of IL-24 might promote anti-tumor immune responses in development novel therapeutic approaches to colorectal adenocarcinoma.

Evaluation and comparison of short chain fatty acids composition in gut diseases

BACKGROUND

An altered (dysbiosis) and unhealthy status of the gut microbiota is usually responsible for a reduction of short chain fatty acids (SCFAs) concentration. SCFAs obtained from the carbohydrate fermentation processes are crucial in maintaining gut homeostasis and their determination in stool samples could provide a faster, reliable and cheaper method to highlight the presence of an intestinal dysbiosis and a biomarker for various gut diseases. We hypothesize that different intestinal diseases, such as celiac disease (CD), adenomatous polyposis (AP) and colorectal cancer (CRC) could display a particular fecal SCFAs' signature.

AIM

To compare the fecal SCFAs' profiles of CD, AP, CRC patients and healthy controls, using the same analytical method.

METHODS

In this cross-sectional study, we defined and compared the SCFAs' concentration in fecal samples of 9 AP, 16 CD, 19 CRC patients and 16 healthy controls (HC). The SCFAs' analysis were performed using a gas-chromatography coupled with mass spectrometry method. Data analysis was carried out using Wilcoxon rank-sum test to assess pairwise differences of SCFAs' profiles, partial least squares-discriminate analysis (PLS-DA) to determine the status membership based on distinct SCFAs' profiles, and Dirichlet regression to determine factors influencing concentration levels of SCFAs.

RESULTS

We have not observed any difference in the SCFAs' amount and composition between CD and healthy control. On the contrary, the total amount of SCFAs was significantly lower in CRC patients compared to HC (P = 0.044) and CD (P = 0.005). Moreover, the SCFAs' percentage composition was different in CRC and AP compared to HC. In detail, HC displayed higher percentage of acetic acid (P value = 1.3 × 10-6) and a lower amount of butyric (P value = 0.02192), isobutyric (P value = 7.4 × 10-5), isovaleric (P value = 0.00012) and valeric (P value = 0.00014) acids compared to CRC patients. AP showed a lower abundance of acetic acid (P value = 0.00062) and higher percentages of propionic (P value = 0.00433) and isovaleric (P value = 0.00433) acids compared to HC. Moreover, AP showed higher levels of propionic acid (P value = 0.03251) and a lower level of isobutyric acid (P value = 0.00427) in comparison to CRC. The PLS-DA model demonstrated a significant separation of CRC and AP groups from HC, although some degree of overlap was observed between CRC and AP.

CONCLUSION

Analysis of fecal SCFAs shows the potential to provide a non-invasive means of diagnosis to detect patients with CRC and AP, while CD patients cannot be discriminated from healthy subjects.

Healthy axis: Towards an integrated view of the gut-brain health

Despite the lack of precise mechanisms of action, a growing number of studies suggests that gut microbiota is involved in a great number of physiological functions of the human organism. In fact, the composition and the relations of intestinal microbial populations play a role, either directly or indirectly, to both the onset and development of various pathologies. In particular, the gastrointestinal tract and nervous system are closely connected by the so-called gut–brain axis, a complex bidirectional system in which the central and enteric nervous system interact with each other, also engaging endocrine, immune and neuronal circuits. This allows us to put forward new working hypotheses on the origin of some multifactorial diseases: from eating to neuropsychiatric disorders (such as autism spectrum disorders and depression) up to diabetes and tumors (such as colorectal cancer). This scenario reinforces the idea that the microbiota and its composition represent a factor, which is no longer negligible, not only in preserving what we call “health” but also in defining and thus determining it. Therefore, we propose to consider the gut-brain axis as the focus of new scientific and clinical investigation as long as the locus of possible systemic therapeutic interventions.

Examining Peripheral and Tumor Cellular Immunome in Patients With Cancer

Immunotherapies are rapidly being integrated into standard of care (SOC) therapy in conjunction with surgery, chemotherapy, and radiotherapy for many cancers and a large number of clinical studies continue to explore immunotherapy alone and as part of combination therapies in patients with cancer. It is evident that clinical effectiveness of immunotherapy is limited to a subset of patients and improving immunotherapy related outcomes remains a major scientific and clinical effort. Understanding the immune cell subset phenotype and activation/functional status (cellular immunome) prior to and post therapy is therefore critical to develop biomarkers that (1) will predict if a patient will respond to immunotherapy and (2) are a result of immunotherapy. In this study, we investigated local (tumor) and peripheral (blood) cellular immunome of patients with melanoma, breast cancer, and brain cancer using a rapid and reliable standardized, multiparameter flow cytometry assay. We used this approach to monitor changes in the peripheral cellular immunome in women with breast cancer undergoing SOC therapy. Our analysis is unique because it is conducted using matched fresh tumor tissue and blood from patients in real-time, within 2–3 h of sample acquisition, and provides insight into the innate and adaptive immune cell profile in blood and tumor. Specific to blood, this approach involves no manipulation and evaluates all immune subsets such as T cells, B cells, natural killer (NK) cells, monocytes, dendritic cells (DCs), neutrophils, eosinophils, and basophils using 0.5 ml of blood. Analysis of the corresponding tumor provides much needed insight into the phenotype and activation status of immune cells, especially T and B cells, in the tumor microenvironment vs. the periphery. This analysis will be used to assess baseline and therapy-mediated changes in local and peripheral cellular immunome in patients with glioblastoma, breast cancer, and melanoma in planned immunotherapy clinical studies.

Differential Responses of Colorectal Cancer Cell Lines to Enterococcus faecalis' Strains Isolated from Healthy Donors and Colorectal Cancer Patients

The metabolites produced by the host’s gut microbiota have an important role in the maintenance of intestinal homeostasis, but can also act as toxins and induce DNA damage in colorectal epithelial cells increasing the colorectal cancer (CRC) chance. In this scenario, the impact of some of the components of the natural human gastrointestinal microbiota, such as Enterococcus faecalis (E. faecalis), at the onset of CRC progression remains controversial. Since under dysbiotic conditions it could turn into a pathogen, the aim of this study was to compare the effect of E. faecalis’ strains (isolated from CRC patients and healthy subjects’ stools) on the proliferation of different colorectal cells lines. First, we isolated and genotyping characterized the Enterococcus faecalis’ strains. Then, we analyzed the proliferation index (by 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay) of three tumor and one normal intestinal cell lines, previously exposed to E. faecalis strains pre-cultured medium. Stool samples of CRC patients demonstrated a reduced frequency of E. faecalis compared to healthy subjects. In addition, the secreted metabolites of E. faecalis’ strains, isolated from healthy donors, decreased the human ileocecal adenocarcinoma cell line HCT-8 and human colon carcinoma cell line HCT-116 cell proliferation without effects on human colorectal adenocarcinoma cell line SW620 and on normal human diploid cell line CLR-1790. Notably, the metabolites of the strains isolated from CRC patients did not influence the cell growth of CRC cell lines. Our results demonstrated a new point of view in the investigation of E. faecalis’ role in CRC development, which raises awareness of the importance of not only associating the presence/absence of a unique microorganism, but also in defining the specific characteristics of the different investigated strains.

Regulatory T Cells and Plasmacytoid Dendritic Cells Within the Tumor Microenvironment in Gastric Cancer Are Correlated With Gastric Microbiota Dysbiosis: A Preliminary Study

Substantial evidence indicates that gastric microbiota dysbiosis, immune system dysfunction especially immune escape are critical for gastric cancer (GC) occurrence and progression. As two important elements of tumor microenvironment (TME), the relationship between gastric microbiota and tumor-immune microenvironment is still unclear. Our present study aimed to explore the correlation between gastric mucosal microbiota in different microhabitats and its corresponding gastric immunosuppressive cells such as regulatory T cells (Tregs) and plasmacytoid dendritic cells (pDCs) in the TME. A cohort of 64 GC patients without preoperative chemotherapy was enrolled retrospectively, and 60 normal, 61 peritumoral and 59 tumoral tissues were obtained for gastric mucosal microbiota analysis and immunohistochemistry analysis. From different microhabitats, BDCA2⁺pDCs and Foxp3⁺Tregs were observed positively correlated, and increased in tumoral and peritumoral tissues compared to normal ones. The diversity, composition and function of gastric mucosal microbiota also changed more significantly in tumoral tissues than those in normal and peritumoral ones. With pearson's correlation analysis, we found that several non-abundant genera such as Stenotrophomonas and Selenomonas were positively correlated with BDCA2⁺pDCs and Foxp3⁺Tregs, respectively, while Comamonas and Gaiella were negatively correlated with BDCA2⁺pDCs and Foxp3⁺ Tregs, respectively. The increased BDCA2⁺pDCs and Foxp3⁺Tregs might be modulated by gastric mucosal microbiota, both participated in the immunosuppression microenvironment of GC, which might provide evidence to establish new strategies in antitumor therapy targeting on gastric microbiota.

Context-Dependent Effect of Glucocorticoids on the Proliferation, Differentiation, and Apoptosis of Regulatory T Cells: A Review of the Empirical Evidence and Clinical Applications

Glucocorticoids (GCs) are widely used to treat several diseases because of their powerful anti-inflammatory and immunomodulatory effects on immune cells and non-lymphoid tissues. The effects of GCs on T cells are the most relevant in this regard. In this review, we analyze how GCs modulate the survival, maturation, and differentiation of regulatory T (Treg) cell subsets into both murine models and humans. In this way, GCs change the Treg cell number with an impact on the mid-term and long-term efficacy of GC treatment. In vitro studies suggest that the GC-dependent expansion of Treg cells is relevant when they are activated. In agreement with this observation, the GC treatment of patients with established autoimmune, allergic, or (auto)inflammatory diseases causes an expansion of Treg cells. An exception to this appears to be the local GC treatment of psoriatic lesions. Moreover, the effects on Treg number in patients with multiple sclerosis are uncertain. The effects of GCs on Treg cell number in healthy/diseased subjects treated with or exposed to allergens/antigens appear to be context-dependent. Considering the relevance of this effect in the maturation of the immune system (tolerogenic response to antigens), the success of vaccination (including desensitization), and the tolerance to xenografts, the findings must be considered when planning GC treatment.

The Interplay between Immunity and Microbiota at Intestinal Immunological Niche: The Case of Cancer

The gut microbiota is central to the pathogenesis of several inflammatory and autoimmune diseases. While multiple mechanisms are involved, the immune system clearly plays a special role. Indeed, the breakdown of the physiological balance in gut microbial composition leads to dysbiosis, which is then able to enhance inflammation and to influence gene expression. At the same time, there is an intense cross-talk between the microbiota and the immunological niche in the intestinal mucosa. These interactions may pave the way to the development, growth and spreading of cancer, especially in the gastro-intestinal system. Here, we review the changes in microbiota composition, how they relate to the immunological imbalance, influencing the onset of different types of cancer and the impact of these mechanisms on the efficacy of traditional and upcoming cancer treatments.

Role of diet and gut microbiota on colorectal cancer immunomodulation

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers, and it is characterized by genetic and epigenetic alterations, as well as by inflammatory cell infiltration among malignant and stromal cells. However, this dynamic infiltration can be influenced by the microenvironment to promote tumor proliferation, survival and metastasis or cancer inhibition. In particular, the cancer microenvironment metabolites can regulate the inflammatory cells to induce a chronic inflammatory response that can be a predisposing condition for CRC retention. In addition, some nutritional components might contribute to a chronic inflammatory condition by regulating various immune and inflammatory pathways. Besides that, diet strongly modulates the gut microbiota composition, which has a key role in maintaining gut homeostasis and is associated with the modulation of host inflammatory and immune responses. Therefore, diet has a fundamental role in CRC initiation, progression and prevention. In particular, functional foods such as probiotics, prebiotics and symbiotics can have a potentially positive effect on health beyond basic nutrition and have anti-inflammatory effects. In this review, we discuss the influence of diet on gut microbiota composition, focusing on its role on gut inflammation and immunity. Finally, we describe the potential benefits of using probiotics and prebiotics to modulate the host inflammatory response, as well as its application in CRC prevention and treatment.

The Gut⁻Brain Axis in the Neuropsychological Disease Model of Obesity: A Classical Movie Revised by the Emerging Director "Microbiome"

The worldwide epidemic of obesity has become an important public health issue, with serious psychological and social consequences. Obesity is a multifactorial disorder in which various elements (genetic, host, and environment), play a definite role, even if none of them satisfactorily explains its etiology. A number of neurological comorbidities, such as anxiety and depression, charges the global obesity burden, and evidence suggests the hypothesis that the brain could be the seat of the initial malfunction leading to obesity. The gut microbiome plays an important role in energy homeostasis regulating energy harvesting, fat deposition, as well as feeding behavior and appetite. Dietary patterns, like the Western diet, are known to be a major cause of the obesity epidemic, probably promoting a dysbiotic drift in the gut microbiota. Moreover, the existence of a "gut⁻brain axis" suggests a role for microbiome on hosts' behavior according to different modalities, including interaction through the nervous system, and mutual crosstalk with the immune and the endocrine systems. In the perspective of obesity as a real neuropsychological disease and in light of the discussed considerations, this review focuses on the microbiome role as an emerging director in the development of obesity.