SOCS3 transactivation by PPARγ prevents IL-17-driven cancer growth

MiR-9 promotes G-MDSC recruitment and tumor proliferation by targeting SOCS3 in breast cancer

Myeloid-derived suppressor cells (MDSCs) are a heterogeneous group of cells that differentiate from myeloid cells, proliferate in cancer and inflammatory reactions, and mainly exert immunosuppressive functions. Nonetheless, the precise mechanisms that dictate both the accumulation and function of MDSCs remain only partially elucidated. In the course of our investigation, we observed a positive correlation between the content of MDSCs especially G-MDSCs and miR-9 level in the tumor tissues derived from miR-9 knockout MMTV-PyMT mice and 4T1 tumor-bearing mice with miR-9 overexpression. Combined with RNA-seq analysis, we identified SOCS2 and SOCS3 as direct targets of miR-9. Additionally, our research unveiled the pivotal role of the CCL5/CCR5 axis in orchestrating the chemotactic recruitment of G-MDSCs within the tumor microenvironment, a process that is enhanced by miR-9. These findings provide fresh insights into the molecular mechanisms governing the accumulation of MDSCs within the framework of breast cancer development.

Antigen-specific memory Th17 cells promote cross-protection against nontypeable Haemophilus influenzae after mild influenza A virus infection

Secondary bacterial pneumonia after influenza A virus (IAV) infection is the leading cause of hospitalization and death associated with IAV infection worldwide. Nontypeable Haemophilus influenzae (NTHi) is one of the most common causes of secondary bacterial pneumonia. Current efforts to develop vaccines against NTHi infection focus on inducing antibodies but are hindered by antigenic diversity among NTHi strains. Therefore, we investigated the contribution of the memory T helper type 17 (Th17) response in protective immunity against IAV/NTHi coinfection. We observed that even a mild IAV infection impaired the NTHi-specific Th17 response and increased morbidity and mortality compared with NTHi monoinfected mice. However, pre-existing memory NTHi-specific Th17 cells induced by a previous NTHi infection overcame IAV-driven Th17 inhibition and were cross-protective against different NTHi strains. Last, mice immunized with a NTHi protein that induced a strong Th17 memory response were broadly protected against diverse NTHi strains after challenge with coinfection. These results indicate that vaccination that limits IAV infection to mild disease may be insufficient to eliminate the risk of a lethal secondary bacterial pneumonia. However, NTHi-specific memory Th17 cells provide serotype-independent protection despite an ongoing IAV infection and demonstrate the advantage of developing broadly protective Th17-inducing vaccines against secondary bacterial pneumonia.

Lutein inhibits IL‑6 expression by inducing PPAR‑γ activation and SOCS3 expression in cerulein‑stimulated pancreatic acinar cells

Acute pancreatitis is a severe inflammatory disease of the pancreas. In experimental acute pancreatitis, cerulein induces the expression of interleukin-6 (IL-6) by activating Janus kinase (JAK) 2/signal transducer and activator of transcription (STAT) 3 in pancreatic acinar cells. Ligands of peroxisome proliferator activated receptor-γ (PPAR-γ) and suppressor of cytokine signaling (SOCS) 3 inhibit IL-6 expression by suppressing JAK2/STAT3 in cerulein-stimulated pancreatic acinar AR42J cells. Lutein, an oxygenated carotenoid, upregulates and activates PPAR-γ to regulate inflammation in a renal injury model. The present study aimed to determine whether lutein activated PPAR-γ and induced SOCS3 expression in unstimulated AR42J cells, and whether lutein inhibited activation of JAK2/STAT3 and IL-6 expression via activation of PPAR-γ and SOCS3 expression in cerulein-stimulated AR42J cells. The anti-inflammatory mechanism of lutein was determined using reverse transcription-quantitative PCR, western blot analysis and enzyme-linked immunosorbent assay in AR42J cells stimulated with or without cerulein. In another experiment, cells were treated with lutein and the PPAR-γ antagonist GW9662 or the PPAR-γ agonist troglitazone prior to cerulein stimulation to determine the involvement of PPAR-γ activation. The results indicated that lutein increased PPAR-γ and SOCS3 levels in unstimulated cells. Cerulein increased phospho-specific forms of JAK2 and STAT3, and mRNA and protein expression of IL-6, but decreased SOCS3 levels in AR42J cells. Cerulein-induced alterations were suppressed by lutein or troglitazone. GW9662 alleviated the inhibitory effect of lutein on JAK2/STAT3 activation and IL-6 expression in cerulein-stimulated cells. In conclusion, lutein inhibited the activation of JAK2/STAT3 and reduced IL-6 levels via PPAR-γ-mediated SOCS3 expression in pancreatic acinar cells stimulated with cerulein.

Peroxisome Proliferator-Activated Receptors and the Hallmarks of Cancer

Peroxisome proliferator-activated receptors (PPARs) function as nuclear transcription factors upon the binding of physiological or pharmacological ligands and heterodimerization with retinoic X receptors. Physiological ligands include fatty acids and fatty-acid-derived compounds with low specificity for the different PPAR subtypes (alpha, beta/delta, and gamma). For each of the PPAR subtypes, specific pharmacological agonists and antagonists, as well as pan-agonists, are available. In agreement with their natural ligands, PPARs are mainly focused on as targets for the treatment of metabolic syndrome and its associated complications. Nevertheless, many publications are available that implicate PPARs in malignancies. In several instances, they are controversial for very similar models. Thus, to better predict the potential use of PPAR modulators for personalized medicine in therapies against malignancies, it seems necessary and timely to review the three PPARs in relation to the didactic concept of cancer hallmark capabilities. We previously described the functions of PPAR beta/delta with respect to the cancer hallmarks and reviewed the implications of all PPARs in angiogenesis. Thus, the current review updates our knowledge on PPAR beta and the hallmarks of cancer and extends the concept to PPAR alpha and PPAR gamma.

Astilbin Activates the Reactive Oxidative Species/PPARγ Pathway to Suppress Effector CD4+ T Cell Activities via Direct Binding With Cytochrome P450 1B1

Astilbin, as a compound of flavonoids, exerts anti-inflammation, antioxidation, and immune-suppression activities. Decreased activation of NF-κB and p38 MAPK and increased activation of SOCS3 and AMPK have been found in astilbin-treated cells. However, what molecules are docked by astilbin to initiate signaling cascades and result in functional changes remains unknown. In the study, we found that astilbin efficiently suppressed TNF-α production and increased CCR9 and CD36 expression of CD4⁺ T cells. In vivo administration of astilbin repressed the occurrence of type 1 diabetes mellitus in non-obese diabetic mice. The PPARγ/SOCS3, PPARγ/PTEN, and PPARγ/AMPK signaling pathways were substantially activated and played key roles in astilbin-induced downregulation of CD4⁺ T cell functions. Transcriptome sequencing results confirmed the changes of signaling molecules involved in the immune system, inflammatory responses, and indicated variations of multiple enzymes with oxidant or antioxidant activities. Astilbin directly induced cytoplasmic ROS production of CD4⁺ T cells ex vivo, but had no effects on mitochondrial ROS and mitochondrial weight. When cellular ROS was depleted, astilbin-treated CD4⁺ T cells remarkably reversed the expression of TNF-α, IFN-γ, CCR9, CD36, and signaling molecules (PPARγ, PTEN, p-AMPK, and SOCS3). Based on bioinformatics, two P450 enzymes (CYP1B1 and CYP19A1) were selected as candidate receptors for astilbin. CYP1B1 was identified as a real docking protein of astilbin in ROS production by AutoDock Vina software analysis and surface plasmon resonance assay. Collectively, astilbin downregulates effector CD4⁺ T cell activities via the CYP1B1/ROS/PPARγ pathway, which firmly supports its potential use in the treatment of inflammation.

Impact of Lipid Metabolism on Antitumor Immune Response

Simple Summary

One of the causes of failure of anticancer therapies is the reprogramming of lipid metabolism. Cells of innate and adaptive immunity present in the tumor microenvironment can be affected by this metabolic switch and thus present changes in their anti- or protumor phenotype. In this review, modifications induced by lipid metabolism will be described for innate immune cells, such as macrophages, dendritic cells and MDSCs, and also for adaptive immune cells, such as CD4+ and CD8+ T cells and B cells. Finally, antitumor therapeutic strategies targeting lipid metabolism will be presented.

Abstract

Over the past decade, metabolic reprogramming has been defined as a hallmark of cancer. More recently, a large number of studies have demonstrated that metabolic reprogramming can modulate the differentiation and functions of immune cells, and thus modify the antitumor response. Increasing evidence suggests that modified energy metabolism could be responsible for the failure of antitumor immunity. Indeed, tumor-infiltrating immune cells play a key role in cancer, and metabolic switching in these cells has been shown to help determine their phenotype: tumor suppressive or immune suppressive. Recent studies in the field of immunometabolism focus on metabolic reprogramming in the tumor microenvironment (TME) by targeting innate and adaptive immune cells and their associated anti- or protumor phenotypes. In this review, we discuss the lipid metabolism of immune cells in the TME as well as the effects of lipids; finally, we expose the link between therapies and lipid metabolism.

Cross-Platform in-silico Analyses Exploring Tumor Immune Microenvironment with Prognostic Value in Triple-Negative Breast Cancer

INTRODUCTION

Only a proportion of triple-negative breast cancer (TNBC) is immunotherapy-responsive. We hypothesized that the tumor microenvironment (TME) influences the outcomes of TNBC and investigated the relevant signaling pathways.

MATERIALS AND METHODS

Immune score (IS) and stromal score (SS) were calculated using the ESTIMATE and correlated with the overall survival (OS) in TNBC. RNA-seq data from 115 TNBC samples and 112 normal adjacent tissues were retrieved. Validations in the methylation levels in 10 TNBC and five non-TNBC cell lines were obtained. Cox model overall survival (OS) validated the derived transcription factor (TF) genes in cBioPortal breast cancer patients.

RESULTS

SS-low predicts a higher OS compared with SS-high patients (P = 0.0081 IS-high/SS-low patients had better OS (P = 0.045) than IS-low/SS-high patients. More macrophages were polarized to the M2 state in patients with IS-low/SS-high patients (P < 0.001). Moreover, CIBERSORTx showed more CD8+ cytotoxic T-cells in IS-high/SS-low patients (p = 0.0286) and more resting NK cells in the IS-low/SS-high TME (P = 0.0108). KEGG pathway analysis revealed that overexpressed genes were enriched in the IL-17 and cytokine-cytokine receptor interaction pathways. The lncRNA DRAIC, a tumor suppressor, was consistently deactivated in the 10 TNBC cell lines. On the cBioPortal platform, we validated that 13% of ER-negative, HER2-unamplified BC harbored IL17RA deep deletion and 25% harbored TRAF3IP2 amplification. On cBioPortal datasets, the nine altered TF genes derived from the X2K analysis showed significantly worse relapse-free survival in 2377 patients and OS in 4819 invasive BC patients than in the unaltered cohort.

CONCLUSION

Of note, the results of this integrated in silico study can only be generalized to approximately 17% of patients with TNBC, in which infiltrating stromal cells and immune cells play a determinant prognostic role.

An Adaptive Transfer-Learning-Based Deep Cox Neural Network for Hepatocellular Carcinoma Prognosis Prediction

Background

Predicting hepatocellular carcinoma (HCC) prognosis is important for treatment selection, and it is increasingly interesting to predict prognosis through gene expression data. Currently, the prognosis remains of low accuracy due to the high dimension but small sample size of liver cancer omics data. In previous studies, a transfer learning strategy has been developed by pre-training models on similar cancer types and then fine-tuning the pre-trained models on the target dataset. However, transfer learning has limited performance since other cancer types are similar at different levels, and it is not trivial to balance the relations with different cancer types.

Methods

Here, we propose an adaptive transfer-learning-based deep Cox neural network (ATRCN), where cancers are represented by 12 phenotype and 10 genotype features, and suitable cancers were adaptively selected for model pre-training. In this way, the pre-trained model can learn valuable prior knowledge from other cancer types while reducing the biases.

Results

ATRCN chose pancreatic and stomach adenocarcinomas as the pre-training cancers, and the experiments indicated that our method improved the C-index of 3.8% by comparing with traditional transfer learning methods. The independent tests on three additional HCC datasets proved the robustness of our model. Based on the divided risk subgroups, we identified 10 HCC prognostic markers, including one new prognostic marker, TTC36. Further wet experiments indicated that TTC36 is associated with the progression of liver cancer cells.

Conclusion

These results proved that our proposed deep-learning-based method for HCC prognosis prediction is robust, accurate, and biologically meaningful.

Harnessing TH9 cells in cancer immunotherapy

CD4 T cell effector subsets not only profoundly affect cancer progression, but recent evidence also underscores their critical contribution to the anticancer efficacy of immune checkpoint inhibitors. In 2012, the two seminal studies suggested the superior antimelanoma activity of T_H9 cells over other T cell subsets upon adoptive T cell transfer. While these findings provided great impetus to investigate further the unique functions of T_H9 cells and explore their relevance in cancer immunotherapy, the following questions still remain outstanding: are T_H9 cell anticancer functions restricted to melanoma? What are the factors favouring T_H9 cell effector functions? What is the contribution of T_H9 cells to cancer immunotherapy treatments? Can T_H9 cells be identified in humans and, if so, what is their clinical relevance? By reviewing the studies addressing these questions, we will discuss how T_H9 cells could be therapeutically harnessed for cancer immunotherapy strategies.

IL-6 in inflammation, autoimmunity and cancer

IL-6 is involved both in immune responses and in inflammation, hematopoiesis, bone metabolism and embryonic development. IL-6 plays roles in chronic inflammation (closely related to chronic inflammatory diseases, autoimmune diseases and cancer) and even in the cytokine storm of corona virus disease 2019 (COVID-19). Acute inflammation during the immune response and wound healing is a well-controlled response, whereas chronic inflammation and the cytokine storm are uncontrolled inflammatory responses. Non-immune and immune cells, cytokines such as IL-1β, IL-6 and tumor necrosis factor alpha (TNFα) and transcription factors nuclear factor-kappa B (NF-κB) and signal transducer and activator of transcription 3 (STAT3) play central roles in inflammation. Synergistic interactions between NF-κB and STAT3 induce the hyper-activation of NF-κB followed by the production of various inflammatory cytokines. Because IL-6 is an NF-κB target, simultaneous activation of NF-κB and STAT3 in non-immune cells triggers a positive feedback loop of NF-κB activation by the IL-6-STAT3 axis. This positive feedback loop is called the IL-6 amplifier (IL-6 Amp) and is a key player in the local initiation model, which states that local initiators, such as senescence, obesity, stressors, infection, injury and smoking, trigger diseases by promoting interactions between non-immune cells and immune cells. This model counters dogma that holds that autoimmunity and oncogenesis are triggered by the breakdown of tissue-specific immune tolerance and oncogenic mutations, respectively. The IL-6 Amp is activated by a variety of local initiators, demonstrating that the IL-6-STAT3 axis is a critical target for treating diseases.

Modulation of CD4 T Cell Response According to Tumor Cytokine Microenvironment

The advancement of knowledge on tumor biology over the past decades has demonstrated a close link between tumor cells and cells of the immune system. In this context, cytokines have a major role because they act as intermediaries in the communication into the tumor bed. Cytokines play an important role in the homeostasis of innate and adaptive immunity. In particular, they participate in the differentiation of CD4 T lymphocytes. These cells play essential functions in the anti-tumor immune response but can also be corrupted by tumors. The differentiation of naïve CD4 T cells depends on the cytokine environment in which they are activated. Additionally, at the tumor site, their activity can also be modulated according to the cytokines of the tumor microenvironment. Thus, polarized CD4 T lymphocytes can see their phenotype evolve, demonstrating functional plasticity. Knowledge of the impact of these cytokines on the functions of CD4 T cells is currently a source of innovation, for therapeutic purposes. In this review, we discuss the impact of the major cytokines present in tumors on CD4 T cells. In addition, we summarize the main therapeutic strategies that can modulate the CD4 response through their impact on cytokine production.

Zinc, ω-3 polyunsaturated fatty acids and vitamin D: An essential combination for prevention and treatment of cancers

Zinc, ω-3 polyunsaturated fatty acids (PUFAs) and vitamin D are essential nutrients for health, maturation and general wellbeing. Extensive literature searches have revealed the widespread similarity in molecular biological properties of zinc, ω-3 PUFAs and vitamin D, and their similar anti-cancer properties, even though they have different modes of action. These three nutrients are separately essential for good health, especially in the aged. Zinc, ω-3 PUFAs and vitamin D are inexpensive and safe as they are fundamentally natural and have the properties of correcting and inhibiting undesirable actions without disturbing the normal functions of cells or their extracellular environment. This review of the anticancer properties of zinc, ω-3 PUFAs and vitamin D is made in the context of the hallmarks of cancer. The anticancer properties of zinc, ω-3 PUFAs and vitamin D can therefore be used beneficially through combined treatment or supplementation. It is proposed that sufficiency of zinc, ω-3 PUFAs and vitamin D is a necessary requirement during chemotherapy treatment and that clinical trials can have questionable integrity if this sufficiency is not checked and maintained during efficacy trials.

Synergistic antitumor activity of DHA and JQ1 in colorectal carcinoma

Colon cancer is still a major disease plaguing humans. In this study, we evaluated the synergistic antitumor effects of the combination of BRD4 inhibitor JQ1 and docosahexaenoic acid (DHA) in colon cancer. We demonstrated that simultaneous exposure to JQ1 and DHA resulted in strong synergistic antiproliferative and proapoptotic effects related to inhibition of expression of c-Myc and activation of NF-κB in colon cancer cell lines. At the same time, the synergetic anticancer effect had been confirmed in vivo. For in vivo experiments, JQ1 and DHA resulted in more significant tumor growth inhibition (53.7%) in a human colon cancer HCT116 xenograft model, comparing with the moderate inhibition in JQ1-treated (31.9%) or DHA-treated groups (20.3%). Because DHA is the predominant component of fish oil, our data suggest that this nontoxic dietary supplement could be administered with BRD4 inhibitor during therapy for CRC, which lay an important foundation for the development of therapeutic regimens for CRC.

PPARs and Angiogenesis-Implications in Pathology

Peroxisome proliferator-activated receptors (PPARs) belong to the family of ligand-activated nuclear receptors. The PPAR family consists of three subtypes encoded by three separate genes: PPARα (NR1C1), PPARβ/δ (NR1C2), and PPARγ (NR1C3). PPARs are critical regulators of metabolism and exhibit tissue and cell type-specific expression patterns and functions. Specific PPAR ligands have been proposed as potential therapies for a variety of diseases such as metabolic syndrome, cancer, neurogenerative disorders, diabetes, cardiovascular diseases, endometriosis, and retinopathies. In this review, we focus on the knowledge of PPAR function in angiogenesis, a complex process that plays important roles in numerous pathological conditions for which therapeutic use of PPAR modulation has been suggested.

Red Wine Extract Disrupts Th17 Lymphocyte Differentiation in a Colorectal Cancer Context

SCOPE

Scope: It is well established that immune response and inflammation promote tumoral progression. Immune cells communicate through direct contact or through cytokine secretion, and it is the pro-inflammatory status that will tip the balance toward tumor progression or anti-tumor immunity. It is demonstrated here that a red wine extract (RWE) can decrease inflammation through its action on the inflammasome complex. This study determines whether an RWE could impact other key actors of inflammation, including T helper 17 (Th17) immune cells in particular.

METHODS AND RESULTS

Methods and results: Using an RWE containing 4.16 g of polyphenols/liter of wine, it is shown that RWE decreases colorectal cancer cells in vitro and induces a reduction in colorectal tumor growth associated with a decrease in tumor-infiltrating lymphocytes in vivo. The process of T-lymphocyte differentiation in Th17 cells is altered by RWE, as revealed by the decrease in the expression of key actors controlling this process, such as signal transducer and activator of transcription 3 and retinoid acid-related orphan receptor γt. This disruption is associated with an inhibition of inflammatory interleukin 17 secretion.

CONCLUSION

The data highlights the major involvement of Th17 immune cells in the biological effects of an RWE.

STAT3, a Master Regulator of Anti-Tumor Immune Response

Immune cells in the tumor microenvironment regulate cancer growth. Thus cancer progression is dependent on the activation or repression of transcription programs involved in the proliferation/activation of lymphoid and myeloid cells. One of the main transcription factors involved in many of these pathways is the signal transducer and activator of transcription 3 (STAT3). In this review we will focus on the role of STAT3 and its regulation, e.g. by phosphorylation or acetylation in immune cells and how it might impact immune cell function and tumor progression. Moreover, we will review the ability of STAT3 to regulate checkpoint inhibitors.

Involvement of TLR4/ CXCL9/ PREX-2 pathway in the development of hepatocellular carcinoma (HCC) and the promising role of early administration of lactobacillus plantarum in Wistar rats

BACKGROUND AND AIM

Improvement of gut microbiota may help in preventing the progression of cirrhosis. We supposed that Lactobacillus Plantarum (L. Plantarum) protects the cirrhotic liver through suppression of TLR4/ CXCL9/ PREX-2.

METHODOLOGY

Rats were divided into two groups. Group I, lasts for six weeks and Group II lasts for 12 weeks. Each group was subdivided into: naïve, Lactobacillus Plantarum (L. Plantarum), thioacetamide (TAA) and TAA + L. Plantarum. Liver function tests, α fetoprotein (AFP) levels, CXCL9, PREX-2 and TLR4 expression were assessed. Histological studies were performed.

RESULTS

TAA induced significant deterioration in liver functions and increased AFP. There was periportal cirrhosis, vacuolated hepatocytes, decrease hepatocyte parrafin-1 (hep par-1) expression, increase proliferating cell nuclear antigen (PCNA) positive nuclei and cytokeratin AE1/AE3. The PCR results showed significant increase in TLR4, CXCL9 and PREX-2 expression. Early administration of L. Plantarum significantly decreased the expression of TLR4, CXCL9 and PREX-2 together with improvement in liver function and prevented the pathological changes.

CONCLUSIONS

The cirrhotic complications induced by TAA are through activation of TLR4/ CXCL9/ PREX-2 pathway and could be prevented by the early administration of L. Plantarum.

Docosahexaenoic acid inhibits both NLRP3 inflammasome assembly and JNK-mediated mature IL-1β secretion in 5-fluorouracil-treated MDSC: implication in cancer treatment

Limitation of 5-fluorouracil (5-FU) anticancer efficacy is due to IL-1β secretion by myeloid-derived suppressor cells (MDSC), according to a previous pre-clinical report. Release of mature IL-1β is a consequence of 5-FU-mediated NLRP3 activation and subsequent caspase-1 activity in MDSC. IL-1β sustains tumor growth recovery in 5-FU-treated mice. Docosahexaenoic acid (DHA) belongs to omega-3 fatty acid family and harbors both anticancer and anti-inflammatory properties, which could improve 5-FU chemotherapy. Here, we demonstrate that DHA inhibits 5-FU-induced IL-1β secretion and caspase-1 activity in a MDSC cell line (MSC-2). Accordingly, we showed that DHA-enriched diet reduces circulating IL-1β concentration and tumor recurrence in 5-FU-treated tumor-bearing mice. Treatment with 5-FU led to JNK activation through ROS production in MDSC. JNK inhibitor SP600125 as well as DHA-mediated JNK inactivation decreased IL-1β secretion. The repression of 5-FU-induced caspase-1 activity by DHA supplementation is partially due to β-arrestin-2-dependent inhibition of NLRP3 inflammasome activity but was independent of JNK pathway. Interestingly, we showed that DHA, through β-arrestin-2-mediated inhibition of JNK pathway, reduces V5-tagged mature IL-1β release induced by 5-FU, in MDSC stably overexpressing a V5-tagged mature IL-1β form. Finally, we found a negative correlation between DHA content in plasma and the induction of caspase-1 activity in HLA-DR- CD33+ CD15+ MDSC of patients treated with 5-FU-based chemotherapy, strongly suggesting that our data are clinical relevant. Together, these data provide new insights on the regulation of IL-1β secretion by DHA and on its potential benefit in 5-FU-based chemotherapy.

Immunomodulatory Effects of Flavonoids: Possible Induction of T CD4+ Regulatory Cells Through Suppression of mTOR Pathway Signaling Activity

The increasing rate of autoimmune disorders and cancer in recent years has been a controversial issue in all aspects of prevention, diagnosis, prognosis and treatment. Among dietary factors, flavonoids have specific immunomodulatory effects that might be of importance to several cancers. Over different types of immune cells, T lymphocytes play a critical role in protecting the immune system as well as in the pathogenesis of specific autoimmune diseases. One of the important mediators of metabolism and immune system is mTOR, especially in T lymphocytes. In the current review, we assessed the effects of flavonoids on the immune system and then their impact on the mTOR pathway. Flavonoids can suppress mTOR activity and are consequently able to induce the T regulatory subset.

Transcriptional Programs Underlying Cd4 T Cell Differentiation and Functions

Understanding the basis of cellular differentiation is a fundamental issue in developmental biology but also for the comprehension of pathological processes. In fact, the palette of developmental decisions for naive CD4 T cells is a critical aspect of the development of appropriate immune responses which could control infectious processes or cancer growth. However, the current accumulation of data on CD4 T cells biology reveals a complex world with different helper populations. Naive CD4 T cells can differentiate into different subtypes in response to cytokine stimulation. This stimulation involves a complex transcriptional network implicating the activation of Signal Transducer and Activator of Transcription but also master regulator transcription factors allowing the functions of each helper T lymphocyte subtype. In this review, we will present an overview of the transcriptional regulation which controls process of helper T cells differentiation. We will focus on the role of initiator transcriptional factors and on master regulators but also on other nonspecific transcriptional factors which refine the T helper polarization to stabilize or modulate the differentiation program.

Effect of cadmium exposure on essential omega-3 fatty acids in the edible bivalve Donax trunculus

Donax trunculus is the most consumed bivalve by the local population of the Northeast Algeria for its nutritional value. Therefore, the aim of the current study was to determine the effects of cadmium (Cd), a known toxic metal, on the alterations in main essential omega-3 fatty acids, i.e., eicosapentaenoic acid (EPA; C20:5n-3) and docosahexaenoic acid (DHA; C22:6n-3), in male and female gonads of D. trunculus during the reproduction period at spring (before spawning). Additionally, this work seeks to describe the relation between EPA and DHA with non-methylene-interrupted dienoic (NMID) fatty acids, and explores their possible contribution of to protect against Cd stress. The samples were collected at El Battah, a relatively clean sea shore, and reared in the laboratory. Physico-chemical parameters such as temperature, pH, salinity, and dissolved oxygen were measured. Cd was added to the rearing water at two sublethal concentrations (LC₁₀ and LC₂₅-96h, as determined previously). A two-way ANOVA analysis indicated significant effects of concentrations and genders for both fatty acids. Our results showed a significant reduction in EPA and DHA concentrations in the both genders, with a strong effect in females. There was also a negative correlation between NMID fatty acids and the two essential omega-3 fatty acids for each gender.

Combination treatment of docosahexaenoic acid (DHA) and all-trans-retinoic acid (ATRA) inhibit IL-17 and RORγt gene expression in PBMCs of patients with relapsing-remitting multiple sclerosis

OBJECTIVES

Multiple sclerosis (MS) is a demyelinating disorder with a complex autoimmune pathophysiology. Its initiation and progression correlate with IL-17 and the related transcription factor, RORγt. All-trans retinoic acid (ATRA) is a bioactive derivative of vitamin A, and docosahexaenoic acid (DHA) is an active metabolite of omega-3 fatty acid; both have immunomodulatory effects in many immune disorders. This study investigated the effects of DHA and ATRA individually and in combination on IL-17 and RORγt gene expression in peripheral blood mononuclear cells (PBMCs) of relapsing-remitting MS (RRMS) patients who were receiving interferon beta (IFN-β).

METHODS

The PBMCs of 15 RRMS patients were treated in vitro with 1 μM of ATRA and 15 μM of DHA as single and combination treatments for assessing probable additive or synergistic effects.

RESULTS

The results showed that single treatment of ATRA (p = 0.05) could significantly decrease the expression of IL-17 gene and single treatment of ATRA (p = 0.04) and single treatment of DHA (p = 0.05) induced significant inhibition on the expression of RORγt gene. The suppressive effect of combined treatment with ATRA and DHA on IL-17 (p = 0.02) and RORγt (p = 0.01) was also found significant showing that the combined treatments can have additive effects.

DISCUSSION

These results indicate that both DHA and ATRA might help control disease progression in IFN-β treated RRMS patients with the strongest effects produced by a combination of the two compounds.

The paradox of Th17 cell functions in tumor immunity

Immune system acts as a host defensive mechanism protecting against attacking pathogens and transformed cells, including cancer cells. Th17 cells are a specific subset of T helper lymphocytes determined by high secretion of IL-17 and other inflammatory cytokines. Th17 cells increase tumor progression by activating angiogenesis and immunosuppressive activities. They can also mediate antitumor immune responses through recruiting immune cells into tumors, stimulating effector CD8+ T cells, or surprisingly by altering toward Th1 phenotype and producing IFN-γ, so Th17 cells are supposed as a double-edged sword in cancer. A comprehensive approach to indicating the activity of Th17 cells in tumor progression could help in the planning of new therapeutic approaches specially targeting Th17 cells in cancer.

Induction of SOCS3 by liver X receptor suppresses the proliferation of hepatocellular carcinoma cells

Liver X receptor (LXR), a member of nuclear receptor superfamily, is involved in the regulation of glucose, lipid and cholesterol metabolism. Recently, it has been reported that LXR suppress different kinds of cancers including hepatocellular carcinoma (HCC). However, the corresponding mechanism is still not well elucidated. In the present study, we found that activation of LXR downregulated cyclin D1 while upregulated p21 and p27 by elevating the level of suppressor of cytokine signaling 3 (SOCS3), leading to the cell cycle arrest at G1/S phase and growth inhibition of HCC cells. Moreover, we demonstrated that LXRα (not LXRβ) mediated the induction of SOCS3 in HCC cells. Subsequently, we showed that LXR activation enhanced the mRNA stability of SOCS3, but had no significant influence on the transcriptional activity of SOCS3 gene promoter. The experiments in nude mice revealed that LXR agonist inhibited the growth of xenograft tumors and enhanced SOCS3 expression in vivo. These results indicate that “LXRα-SOCS3-cyclin D1/p21/p27” is a novel pathway by which LXR exerts its anti-HCC effects, suggesting that the pathway may be a new potential therapeutic target for HCC treatment.

Cross-protective mucosal immunity mediated by memory Th17 cells against Streptococcus pneumoniae lung infection

Pneumonia caused by Streptococcus pneumoniae (Sp) remains a leading cause of serious illness and death worldwide. Immunization with conjugated pneumococcal vaccine has lowered the colonization rate and consequently invasive diseases by inducing serotype-specific antibodies. However, many of the current pneumonia cases result from infection by serotype strains not included in the vaccine. In this study, we asked if cross-protection against lung infection by heterologous strains can be induced, and investigated the underlying immune mechanism. We found that immune mice recovered from a prior infection were protected against heterologous Sp strains in the pneumonia challenge model, as evident by accelerated bacterial clearance, reduced pathology, and apoptosis of lung epithelial cells. Sp infection in the lung induced strong T-helper type 17 (Th17) responses at the lung mucosal site. Transfer of CD4⁺ T cells from immune mice provided heterologous protection against pneumonia, and this protection was abrogated by interleukin-17A (IL-17A) blockade. Transfer of memory CD4⁺ T cells from IL-17A-knockout mice failed to provide protection. These results indicate that memory Th17 cells had a key role in providing protection against pneumonia in a serotype-independent manner and suggest the feasibility of developing a broadly protective vaccine against bacterial pneumonia by targeting mucosal Th17 T cells.

Obese Neuronal PPARγ Knockout Mice Are Leptin Sensitive but Show Impaired Glucose Tolerance and Fertility

The peroxisome-proliferator activated receptor γ (PPARγ) is expressed in the hypothalamus in areas involved in energy homeostasis and glucose metabolism. In this study, we created a deletion of PPARγ brain-knockout (BKO) in mature neurons in female mice to investigate its involvement in metabolism and reproduction. We observed that there was no difference in age at puberty onset between female BKOs and littermate controls, but the BKOs gave smaller litters when mated and fewer oocytes when ovulated. The female BKO mice had regular cycles but showed an increase in the number of cycles with prolonged estrus. The mice also had increased luteinizing hormone (LH) levels during the LH surge and histological examination showed hemorrhagic corpora lutea. The mice were challenged with a 60% high-fat diet (HFD). Metabolically, the female BKO mice showed normal body weight, glucose and insulin tolerance, and leptin levels but were protected from obesity-induced leptin resistance. The neuronal knockout also prevented the reduction in estrous cycles due to the HFD. Examination of ovarian histology showed a decrease in the number of primary and secondary follicles in both genotypes due to the HFD, but the BKO ovaries showed an increase in the number of hemorrhagic follicles. In summary, our results show that neuronal PPARγ is required for optimal female fertility but is also involved in the adverse effects of diet-induced obesity by creating leptin resistance potentially through induction of the repressor Socs3.

ω3 Polyunsaturated Fatty Acids as Immunomodulators in Colorectal Cancer: New Potential Role in Adjuvant Therapies

Diet composition may affect the onset and progression of chronic degenerative diseases, including cancer, whose pathogenesis relies on inflammatory processes. Growing evidence indicates that diet and its components critically contribute to human health, affecting the immune system, secretion of adipokines, and metabolic pathways. Colorectal cancer (CRC) is one of the leading causes of death worldwide. Antineoplastic drugs are widely used for CRC treatment, but drug resistance and/or off-target toxicity limit their efficacy. Dietary ω3 polyunsaturated fatty acids (PUFA) have been gaining great interest in recent years as possible anti-inflammatory and anticancer agents, especially in areas such as the large bowel, where the pro-inflammatory context promotes virtually all steps of colon carcinogenesis. Growing epidemiological, experimental, and clinical evidence suggests that ω3 PUFA may play a role in several stages of CRC management exhibiting antineoplastic activity against human CRC cells, improving the efficacy of radiation and chemotherapy, ameliorating cancer-associated secondary complications, and preventing CRC recurrence. These effects are most likely related to the immunomodulatory activities of ω3 PUFA that are able to influence several aspects of the inflammatory process ranging from inflammasome activation, leukocyte recruitment, production of immune mediators to differentiation, and activation of immune cells. In this review, we will focus on the potential use of ω3 PUFA as adjuvant agents together with chemo/radiotherapy, highlighting the immunomodulatory effects most likely responsible for their beneficial effects in different stages of CRC management.

SOCS3 revisited: a broad regulator of disease, now ready for therapeutic use?

Since their discovery, SOCS have been characterised as regulatory cornerstones of intracellular signalling. While classically controlling the JAK/STAT pathway, their inhibitory effects are documented across several cascades, underpinning their essential role in homeostatic maintenance and disease. After 20 years of extensive research, SOCS3 has emerged as arguably the most important family member, through its regulation of both cytokine- and pathogen-induced cascades. In fact, low expression of SOCS3 is associated with autoimmunity and oncogenesis, while high expression is linked to diabetes and pathogenic immune evasion. The induction of SOCS3 by both viruses and bacteria and its impact upon inflammatory disorders, underscores this protein's increasing clinical potential. Therefore, with the aim of highlighting SOCS3 as a therapeutic target for future development, this review revisits its multi-faceted immune regulatory functions and summarises its role in a broad ranges of diseases.

Anti-inflammatory effects of docosahexaenoic acid: Implications for its cancer chemopreventive potential

The implication of inflammatory tissue damage in pathophysiology of human cancer as well as some metabolic disorders has been under intense investigation. Numerous studies have identified a series of critical signaling molecules involved in cellular responses to inflammatory stimuli. These include nuclear factor κB, peroxisome proliferator-activated receptor γ, nuclear factor erythroid 2 p45-related factor 2 and sterol regulatory element-binding protein 1. The proper regulation of these transcription factors mediating pro- and anti-inflammatory signaling hence provides an important strategy for the chemoprevention of inflammation-associated cancer. There is compelling evidence supporting that dietary supplementation with fish oil-derived ω-3 polyunsaturated fatty acids including docosahexaenoic acid (DHA) ameliorates symptomatic inflammation associated with cancer as well as other divergent human disorders. Acute or physiologic inflammation is an essential body's first line of defence to microbial infection and tissue injuries, but it must be properly completed by a process termed 'resolution'. Failure of resolution mechanisms can result in persistence of inflammation, leading to chronic inflammatory conditions and related malignancies. The phagocytic engulfment of apoptotic neutrophils and clearance of their potentially histotoxic contents by macrophages, called efferocytosis is an essential component in resolving inflammation. Of note, DHA is a precursor of endogenous proresolving lipid mediators which regulate the leukocyte trafficking and recruitment and thereby facilitate efferocytosis. Therefore, DHA and its metabolites may have a preventive potential in the management of human cancer which arises as a consequence of impaired resolution of inflammation as well as chronic inflammation.

FXR induces SOCS3 and suppresses hepatocellular carcinoma

Suppressor of cytokine signaling 3 (SOCS3) is regarded as a vital repressor in the liver carcinogenesis mainly by inhibiting signal transducer and activator of transcription 3 (STAT3) activity. Farnesoid X Receptor (FXR), highly expressed in liver, has an important role in protecting against hepatocellular carcinoma (HCC). However, it is unclear whether the tumor suppressive activity of FXR involves the regulation of SOCS3. In the present study, we found that activation of FXR by its specific agonist GW4064 in HCC cells inhibited cell growth, induced cell cycle arrest at G1 phase, elevated p21 expression and repressed STAT3 activity. The above anti-tumor effects of FXR were dramatically alleviated by knockdown of SOCS3 with siRNA. Reporter assay revealed that FXR activation enhanced the transcriptional activity of SOCS3 promoter. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay displayed that FXR directly bound to IR9 DNA motif within SOCS3 promoter region. The in vivo study in nude mice showed that treatment with FXR ligand GW4064 could decelerate the growth of HCC xenografts, up-regulate SOCS3 and p21 expression and inhibit STAT3 phosphorylation in the xenografts. These results suggest that induction of SOCS3 may be a novel mechanism by which FXR exerts its anti-HCC effects, and the FXR-SOCS3 signaling may serve as a new potential target for the prevention/treatment of HCC.

Quantitative PPARγ expression affects the balance between tolerance and immunity

PPARγ modulates energy metabolism and inflammation. However, its specific functions in the balance of immunity in vivo have been explored incompletely. In this study, by the age of 14 mo, Pparg^C/− mice with PPARγ expression at 25% of the normal level exhibited high autoantibody levels and developed mesangial proliferative glomerulonephritis, which resembled systemic lupus erythematosus (SLE)-like autoimmune disease. These symptoms were preceded by splenomegaly at an early age, which was associated with increases in splenocyte accumulation and B-cell activation but not with relocation of hematopoiesis to the spleen. The mechanism of splenic lymphocyte accumulation involved reduced sphingosine-1-phosphate receptor 1 (S1P₁) expression and diminished migration toward S1P in the Pparg^C/− splenocytes, which impeded lymphocyte egression. Mechanistically, increased Th17 polarization and IL-17 signaling in the Pparg^C/− CD4⁺ T cells contributed to B-cell hyperactivation in the spleen. Finally, the activation of the remaining PPARγ in Pparg^C/− mice by pioglitazone increased S1P₁ levels, reduced the Th17 population in the spleen, and ameliorated splenomegaly. Taken together, our data demonstrated that reduction of Pparg expression in T-helper cells is critical for spontaneous SLE-like autoimmune disease development; we also revealed a novel function of PPARγ in lymphocyte trafficking and cross talk between Th17 and B cells.

Docosahexaenoic acid inhibits Helicobacter pylori-induced STAT3 phosphorylation through activation of PPARγ

SCOPE

The health beneficial effects of docosahexaenoic acid (DHA) have been attributed to its anti-inflammatory properties. However, the molecular mechanism underlying anti-inflammatory effects of DHA remains largely elusive.

METHODS AND RESULTS

In the present study, DHA was found to suppress the phosphorylation and nuclear translocation of signal transducer and activator of transcription 3 (STAT3) induced by Helicobacter pylori infection in human gastric cancer AGS cells. Notably, DHA induced expression of suppressor of cytokine signaling 3 (SOCS3), a negative regulator of STAT3. Knockdown of SOCS3 abolished the suppressive effect of DHA on STAT3(Tyr705) phosphorylation induced by H. pylori infection. DHA also induced nuclear translocation, DNA binding, and transcriptional activities of peroxisome proliferator-activated receptor gamma (PPARγ) in AGS cells. Knockdown of PPARγ inhibited the transcription of SOCS3 and attenuated the suppressive effect of DHA on phosphorylation of STAT3(Tyr705) induced by H. pylori. The PPARγ antagonist bisphenol A diglycidyl ether also mitigated the suppressive effect of DHA on H. pylori-induced phosphorylation of STAT3(Tyr705) . In addition, DHA inhibited the expression of c-Myc, which was attenuated in the AGS cells harboring SOCS3 specific siRNA. DHA also markedly decreased anchorage-independent growth of AGS cells infected by H. pylori.

CONCLUSION

DHA inhibits H. pylori-induced STAT3 phosphorylation in a PPARγ/SOCS3-dependent manner.

Probiotics modulated gut microbiota suppresses hepatocellular carcinoma growth in mice

The beneficial roles of probiotics in lowering the gastrointestinal inflammation and preventing colorectal cancer have been frequently demonstrated, but their immunomodulatory effects and mechanism in suppressing the growth of extraintestinal tumors remain unexplored. Here, we adopted a mouse model and metagenome sequencing to investigate the efficacy of probiotic feeding in controlling s.c. hepatocellular carcinoma (HCC) and the underlying mechanism suppressing the tumor progression. Our result demonstrated that Prohep, a novel probiotic mixture, slows down the tumor growth significantly and reduces the tumor size and weight by 40% compared with the control. From a mechanistic point of view the down-regulated IL-17 cytokine and its major producer Th17 cells, whose levels decreased drastically, played critical roles in tumor reduction upon probiotics feeding. Cell staining illustrated that the reduced Th17 cells in the tumor of the probiotic-treated group is mainly caused by the reduced frequency of migratory Th17 cells from the intestine and peripheral blood. In addition, shotgun-metagenome sequencing revealed the crosstalk between gut microbial metabolites and the HCC development. Probiotics shifted the gut microbial community toward certain beneficial bacteria, including Prevotella and Oscillibacter, that are known producers of antiinflammatory metabolites, which subsequently reduced the Th17 polarization and promoted the differentiation of antiinflammatory Treg/Tr1 cells in the gut. Overall, our study offers novel insights into the mechanism by which probiotic treatment modulates the microbiota and influences the regulation of the T-cell differentiation in the gut, which in turn alters the level of the proinflammatory cytokines in the extraintestinal tumor microenvironment.

Inhibition of colon cancer growth by docosahexaenoic acid involves autocrine production of TNFα

The omega-3 polyunsaturated fatty acid docosahexaenoic acid (DHA) has anti-inflammatory and anti-cancer properties. Among pro-inflammatory mediators, tumor necrosis factor α (TNFα) plays a paradoxical role in cancer biology with induction of cancer cell death or survival depending on the cellular context. The objective of the study was to evaluate the role of TNFα in DHA-mediated tumor growth inhibition and colon cancer cell death. The treatment of human colorectal cancer cells, HCT-116 and HCT-8 cells, with DHA triggered apoptosis in autocrine TNFα-dependent manner. We demonstrated that DHA-induced increased content of TNFα mRNA occurred through a post-transcriptional regulation via the down-regulation of microRNA-21 (miR-21) expression. Treatment with DHA led to nuclear accumulation of Foxo3a that bounds to the miR-21 promoter triggering its transcriptional repression. Moreover, inhibition of RIP1 kinase and AMP-activated protein kinase α reduced Foxo3a nuclear-cytoplasmic shuttling and subsequent increase of TNFα expression through a decrease of miR-21 expression in DHA-treated colon cancer cells. Finally, we were able to show in HCT-116 xenograft tumor-bearing nude mice that a DHA-enriched diet induced a decrease of human miR-21 expression and an increase of human TNFα mRNA expression limiting tumor growth in a cancer cell-derived TNFα dependent manner. Altogether, the present work highlights a novel mechanism for anti-cancer action of DHA involving colon cancer cell death mediated through autocrine action of TNFα.

Gut Microbiota Regulates K/BxN Autoimmune Arthritis through Follicular Helper T but Not Th17 Cells

The bacterial community that colonizes mucosal surfaces helps shape the development and function of the immune system. The K/BxN autoimmune arthritis model is dependent on the microbiota, and particularly on segmented filamentous bacteria, for the autoimmune phenotype. The mechanisms of how the gut microbiota affects arthritis development are not well understood. In this study, we investigate the contribution of two T cell subsets, Th17 and follicular helper T (Tfh), to arthritis and how microbiota modulates their differentiation. Using genetic approaches, we demonstrate that IL-17 is dispensable for arthritis. Antibiotic treatment inhibits disease in IL-17-deficient animals, suggesting that the gut microbiota regulates arthritis independent of Th17 cells. In contrast, conditional deletion of Bcl6 in T cells blocks Tfh cell differentiation and arthritis development. Furthermore, Tfh cell differentiation is defective in antibiotic-treated mice. Taken together, we conclude that gut microbiota regulates arthritis through Tfh but not Th17 cells. These findings have implications in our understanding of how environmental factors contribute to the development of autoimmune diseases.

Methylation and microRNA-mediated epigenetic regulation of SOCS3

Epigenetic gene silencing of several genes causes different pathological conditions in humans, and DNA methylation has been identified as one of the key mechanisms that underlie this evolutionarily conserved phenomenon associated with developmental and pathological gene regulation. Recent advances in the miRNA technology with high throughput analysis of gene regulation further increased our understanding on the role of miRNAs regulating multiple gene expression. There is increasing evidence supporting that the miRNAs not only regulate gene expression but they also are involved in the hypermethylation of promoter sequences, which cumulatively contributes to the epigenetic gene silencing. Here, we critically evaluated the recent progress on the transcriptional regulation of an important suppressor protein that inhibits cytokine-mediated signaling, SOCS3, whose expression is directly regulated both by promoter methylation and also by microRNAs, affecting its vital cell regulating functions. SOCS3 was identified as a potent inhibitor of Jak/Stat signaling pathway which is frequently upregulated in several pathologies, including cardiovascular disease, cancer, diabetes, viral infections, and the expression of SOCS3 was inhibited or greatly reduced due to hypermethylation of the CpG islands in its promoter region or suppression of its expression by different microRNAs. Additionally, we discuss key intracellular signaling pathways regulated by SOCS3 involving cellular events, including cell proliferation, cell growth, cell migration and apoptosis. Identification of the pathway intermediates as specific targets would not only aid in the development of novel therapeutic drugs, but, would also assist in developing new treatment strategies that could successfully be employed in combination therapy to target multiple signaling pathways.

Dysregulation of the suppressor of cytokine signalling 3-signal transducer and activator of transcription-3 pathway in the aetiopathogenesis of Sjögren's syndrome

The suppressor of cytokine signalling 3 (SOCS3) negatively regulates the Janus kinase (JAK)/signal transducer and activator of transcription-3 (STAT-3)/interleukin (IL)-17 pathway. The proinflammatory cytokine IL-17 is over-expressed in Sjögren's syndrome (SS) and is a key factor in its pathogenesis. We hypothesized that IL-17 over-expression in SS results from ineffective regulation by SOCS3. The expression of SOCS3 was analysed in peripheral blood mononuclear cells (PBMC) from SS cases, sicca controls (SC) and healthy controls (HC) and tissue samples from SS, SC and healthy salivary glands (HSG). PBMC and salivary gland tissue from SS and controls were dual-immunostained for SOCS3 and IL-17. IL-6-stimulated PBMC from SS and controls were evaluated for time-dependent STAT-3 activation and SOCS3 induction, and for IL-17 expression. Immunoblotting revealed greater levels of SOCS3 in PBMC from SS than SC (P = 0·017) or HC (P < 0·001). Similarly, the proportion of salivary-gland tissue cells staining for SOCS3 was significantly higher in SS than SC (P = 0·029) or HSG (P = 0·021). The cells in PBMC/salivary gland samples from controls predominantly expressed either SOCS3 or IL-17. However, there was a high frequency of SOCS3/IL-17 co-expression within cells of SS samples. IL-6-stimulation of PBMC from SS cases revealed prolonged activation of STAT-3 with reduced negative regulation by SOCS3, and enhanced expression of IL-17. This study showed that SOCS3 expression is up-regulated in SS. However, the absence in SS of the normal inverse relationship between SOCS3 and pSTAT-3/IL-17 indicates a functional disturbance in this signalling cascade. Consequently, a reduction in function, rather than a reduction in expression of SOCS3 accounts for the unregulated expression of IL-17 in SS, and may play a crucial role in aetiopathogenesis.

Role of Tyk-2 in Th9 and Th17 cells in allergic asthma

In a murine model of allergic asthma, we found that Tyk-2^(−/−) asthmatic mice have induced peribronchial collagen deposition, mucosal type mast cells in the lung, IRF4 and hyperproliferative lung Th2 CD4⁺ effector T cells over-expressing IL-3, IL-4, IL-5, IL-10 and IL-13. We also observed increased Th9 cells expressing IL-9 and IL-10 as well as T helper cells expressing IL-6, IL-10 and IL-21 with a defect in IL-17A and IL-17F production. This T helper phenotype was accompanied by increased SOCS3 in the lung of Tyk-2 deficient asthmatic mice. Finally, in vivo treatment with rIL-17A inhibited local CD4⁺CD25⁺Foxp3⁺ T regulatory cells as well as Th2 cytokines without affecting IL-9 in the lung. These results suggest a role of Tyk-2 in different subsets of T helper cells mediated by SOCS3 regulation that is relevant for the treatment of asthma, cancer and autoimmune diseases.

Interleukin-17 and type 17 helper T cells in cancer management and research

Since their recent discovery, T helper 17 (Th17) cells have been frequently detected in the tumor microenvironment of many malignancies, but their clinical implications remain largely unknown. Interleukin-17 (IL-17) detection is commonly related with poor outcomes in colorectal cancers, yet its presence is associated with antitumor responses in ovarian carcinomas. Numerous experimental models illustrate the divergent roles of Th17 cells in tumor immunity, which appears to be mainly dependent on the tumor context (type, location, and stage of cancer). It is recognized that IL-17 is produced by a variety of cell types and that Th17 cells are endowed with a unique functional plasticity. Therefore, when trying to elucidate potential immune biomarkers and immunotargets, it is extremely important to make a clear dissociation between strategies targeting Th17 versus its hallmark cytokine, IL-17. In this review, we will summarize the data regarding the detection of IL-17 and Th17 in human cancers, consider the experimental evidence on their respective roles in antitumor activity, and discuss the potential of IL-17 as an immune target for therapeutic interventions.

Immune regulatory activity of vitamin d3 in head and neck cancer

While vitamin D exhibits a multitude of cellular effects that can impact on cancer development and progression, this review focuses on its immune modulatory effects. These immune modulatory effects can be both direct and indirect. Compared to other cancer types, head and neck squamous cell carcinomas (HNSCC) have received less attention, but are a fascination immunologically because of the profound extent to which they inhibit immune defenses. This review describes the mechanisms of some of these immune inhibitory processes and how vitamin D can help overcome aspects of this immune suppression.