Transforming growth factor beta blocks Tec kinase phosphorylation, Ca2+ influx, and NFATc translocation causing inhibition of T cell differentiation

Revisiting the role of cancer-associated fibroblasts in tumor microenvironment

Cancer-associated fibroblasts (CAFs) are integral components of the tumor microenvironment playing key roles in tumor progression, metastasis, and therapeutic resistance. However, challenges persist in understanding their heterogeneity, origin, and functional diversity. One major obstacle is the lack of standardized naming conventions for CAF subpopulations, with current systems failing to capture their full complexity. Additionally, the identification of CAFs is hindered by the absence of specific biomarkers, limiting the precision of diagnostic and therapeutic strategies. In vitro culture conditions often fail to maintain the in vivo characteristics of CAFs, which complicates their study and the translation of findings to clinical practice. Although current detection methods, such as antibodies, mRNA probes, and single-cell transcriptomics, offer insights into CAF biology, they lack standardization and fail to provide reliable quantitative measures. Furthermore, the dynamic interactions between CAFs, tumor cells, and immune cells within the TME remain insufficiently understood, and the role of CAFs in immune evasion and therapy resistance is an area of ongoing research. Understanding how CAFs influence drug resistance and the immune response is essential for developing more effective cancer therapies. This review aims to provide an in-depth analysis of the challenges in CAF research, propose future research directions, and emphasize the need for improved CAF-targeted therapeutic strategies. By addressing these gaps, it seeks to highlight the potential of CAFs as targets for overcoming therapeutic resistance and enhancing the efficacy of cancer treatments.

Therapeutic targeting of TGF-β in lung cancer

Transforming growth factor-β (TGF-β) plays a complex role in lung cancer pathophysiology, initially acting as a tumor suppressor by inhibiting early-stage tumor growth. However, its role evolves in the advanced stages of the disease, where it contributes to tumor progression not by directly promoting cell proliferation but by enhancing epithelial-mesenchymal transition (EMT) and creating a conducive tumor microenvironment. While EMT is typically associated with enhanced migratory and invasive capabilities rather than proliferation per se, TGF-β's influence on this process facilitates the complex dynamics of tumor metastasis. Additionally, TGF-β impacts the tumor microenvironment by interacting with immune cells, a process influenced by genetic and epigenetic changes within tumor cells. This interaction highlights its role in immune evasion and chemoresistance, further complicating lung cancer therapy. This review provides a critical overview of recent findings on TGF-β's involvement in lung cancer, its contribution to chemoresistance, and its modulation of the immune response. Despite the considerable challenges encountered in clinical trials and the development of new treatments targeting the TGF-β pathway, this review highlights the necessity for continued, in-depth investigation into the roles of TGF-β. A deeper comprehension of these roles may lead to novel, targeted therapies for lung cancer. Despite the intricate behavior of TGF-β signaling in tumors and previous challenges, further research could yield innovative treatment strategies.

Therapeutic Immunomodulation of Tumor-Lymphatic Crosstalk via Intratumoral Immunotherapy

Intra- and peritumoral lymphatics and tumor-draining lymph nodes play major roles in mediating the adaptive immune response to cancer immunotherapy. Despite this, current paradigms of clinical cancer management seldom seek to therapeutically modulate tumor-lymphatic immune crosstalk. This review explores recent developments that set the stage for how this regulatory axis can be therapeutically manipulated, with a particular emphasis on tumor-localized immunomodulation. Building on this idea, the nature of tumor-lymphatic immune crosstalk and relevant immunotherapeutic targets and pathways are reviewed, with a focus on their translational potential. Engineered drug delivery systems that enhance intratumoral immunotherapy by improving drug delivery to both the tumor and lymph nodes are also highlighted.

TGF-β: an active participant in the immune and metabolic microenvironment of multiple myeloma : TGF-β in the microenvironment of multiple myeloma

Although substantial quantities of potent therapies for multiple myeloma (MM) have been established, MM remains an incurable disease. In recent years, our understanding of the initiation, development, and metastasis of cancers has made a qualitative leap. Cancers attain the abilities to maintain proliferation signals, escape growth inhibitors, resist cell death, induce angiogenesis, and more importantly, escape anti-tumor immunity and reprogram metabolism, which are the hallmarks of cancers. Besides, different cancers have different tumor microenvironments (TME), thus, we pay more attention to the TME in the pathogenesis of MM. Many researchers have identified that myeloma cells interact with the components of TME, which is beneficial for their survival, ultimately causing the formation of immunosuppressive and high-metabolism TME. In the process, transforming growth factor-β (TGF-β), as a pivotal cytokine in the TME, controls various cells' fates and influences numerous metabolic pathways, including inhibiting immune cells to infiltrate the tumors, suppressing the activation of anti-tumor immune cells, facilitating more immunosuppressive cells, enhancing glucose and glutamine metabolism, dysregulating bone metabolism and so on. Thus, we consider TGF-β as the tumor promoter. However, in healthy cells and the early stage of tumors, it functions as a tumor suppressor. Due to the effect of context dependence, TGF-β has dual roles in TME, which attracts us to further explore whether targeting it can overcome obstacles in the treatment of MM by regulating the progression of myeloma, molecular mechanisms of drug resistance, and various signaling pathways in the immune and metabolic microenvironment. In this review, we predominantly discuss that TGF-β promotes the development of MM by influencing immunity and metabolism.

Cholesterol sensing and metabolic adaptation in tissue immunity

Cholesterol metabolites, particularly oxidized forms known as oxysterols, play crucial roles in modulating immune and metabolic processes across various tissues. Concentrations of local cholesterol and its metabolites influence tissue-specific immune responses by shaping the metabolic and spatial organization of immune cells in barrier organs like the small intestine (SI) and lungs. We explore recent molecular and cellular evidence supporting the metabolic adaptation of innate and adaptive immune cells in the SI and lung, driven by cholesterol and cholesterol metabolites. Further research should unravel the detailed molecular mechanisms and spatiotemporal adaptations involving cholesterol metabolites in distinct mucosal tissues in homeostasis or infection. We posit that pharmacological interventions targeting the generation or sensing of cholesterol metabolites might be leveraged to enhance long-term immune protection in mucosal tissues or prevent autoinflammatory states.

Oncogenic Calreticulin Induces Immune Escape by Stimulating TGFβ Expression and Regulatory T-cell Expansion in the Bone Marrow Microenvironment

Increasing evidence supports the interplay between oncogenic mutations and immune escape mechanisms. Strategies to counteract the immune escape mediated by oncogenic signaling could provide improved therapeutic options for patients with various malignancies. As mutant calreticulin (CALR) is a common driver of myeloproliferative neoplasms (MPN), we analyzed the impact of oncogenic CALRdel52 on the bone marrow (BM) microenvironment in MPN. Single-cell RNA sequencing revealed that CALRdel52 led to the expansion of TGFβ1-producing erythroid progenitor cells and promoted the expansion of FoxP3+ regulatory T cells (Treg) in a murine MPN model. Treatment with an anti-TGFβ antibody improved mouse survival and increased the glycolytic activity in CD4+ and CD8+ T cells in vivo, whereas T-cell depletion abrogated the protective effects conferred by neutralizing TGFβ. TGFβ1 reduced perforin and TNFα production by T cells in vitro. TGFβ1 production by CALRdel52 cells was dependent on JAK1/2, PI3K, and ERK activity, which activated the transcription factor Sp1 to induce TGFβ1 expression. In four independent patient cohorts, TGFβ1 expression was increased in the BM of patients with MPN compared with healthy individuals, and the BM of patients with MPN contained a higher frequency of Treg compared with healthy individuals. Together, this study identified an ERK/Sp1/TGFβ1 axis in CALRdel52 MPNs as a mechanism of immunosuppression that can be targeted to elicit T-cell-mediated cytotoxicity. Significance: Targeting the mutant calreticulin/TGFβ1 axis increases T-cell activity and glycolytic capacity, providing the rationale for conducting clinical trials on TGFβ antagonists as an immunotherapeutic strategy in patients with myeloproliferative neoplasms.

A pleiotropic recurrent dominant ITPR3 variant causes a complex multisystemic disease

Inositol 1,4,5-trisphosphate (IP3) receptor type 1 (ITPR1), 2 (ITPR2), and 3 (ITPR3) encode the IP3 receptor (IP3R), a key player in intracellular calcium release. In four unrelated patients, we report that an identical ITPR3 de novo variant-NM_002224.3:c.7570C>T, p.Arg2524Cys-causes, through a dominant-negative effect, a complex multisystemic disorder with immunodeficiency. This leads to defective calcium homeostasis, mitochondrial malfunction, CD4+ lymphopenia, a quasi-absence of naïve CD4+ and CD8+ cells, an increase in memory cells, and a distinct TCR repertoire. The calcium defect was recapitulated in Jurkat knock-in. Site-directed mutagenesis displayed the exquisite sensitivity of Arg2524 to any amino acid change. Despite the fact that all patients had severe immunodeficiency, they also displayed variable multisystemic involvements, including ectodermal dysplasia, Charcot-Marie-Tooth disease, short stature, and bone marrow failure. In conclusion, unlike previously reported ITPR1-3 deficiencies leading to narrow, mainly neurological phenotypes, a recurrent dominant ITPR3 variant leads to a multisystemic disease, defining a unique role for IP3R3 in the tetrameric IP3R complex.

Cancer-associated fibroblasts: a versatile mediator in tumor progression, metastasis, and targeted therapy

Tumor microenvironment (TME) has been demonstrated to play a significant role in tumor initiation, progression, and metastasis. Cancer-associated fibroblasts (CAFs) are the major component of TME and exhibit heterogeneous properties in their communication with tumor cells. This heterogeneity of CAFs can be attributed to various origins, including quiescent fibroblasts, mesenchymal stem cells (MSCs), adipocytes, pericytes, endothelial cells, and mesothelial cells. Moreover, single-cell RNA sequencing has identified diverse phenotypes of CAFs, with myofibroblastic CAFs (myCAFs) and inflammatory CAFs (iCAFs) being the most acknowledged, alongside newly discovered subtypes like antigen-presenting CAFs (apCAFs). Due to these heterogeneities, CAFs exert multiple functions in tumorigenesis, cancer stemness, angiogenesis, immunosuppression, metabolism, and metastasis. As a result, targeted therapies aimed at the TME, particularly focusing on CAFs, are rapidly developing, fueling the promising future of advanced tumor-targeted therapy.

IL-10 and TGF-β, but Not IL-17A or IFN-γ, Potentiate the IL-15-Induced Proliferation of Human T Cells: Association with a Decrease in the Expression of β2m-Free HLA Class I Molecules Induced by IL-15

IL-15 is a homeostatic cytokine for human T and NK cells. However, whether other cytokines influence the effect of IL-15 is not known. We studied the impact that IL-10, TGF-β, IL-17A, and IFN-γ have on the IL-15-induced proliferation of human T cells and the expression of HLA class I (HLA-I) molecules. Peripheral blood lymphocytes (PBLs) were labeled with CFSE and stimulated for 12 days with IL-15 in the absence or presence of the other cytokines. The proportion of proliferating T cells and the expression of cell surface HLA-I molecules were analyzed using flow cytometry. The IL-15-induced proliferation of T cells was paralleled by an increase in the expression of HC-10-reactive HLA-I molecules, namely on T cells that underwent ≥5-6 cycles of cell division. It is noteworthy that the IL-15-induced proliferation of T cells was potentiated by IL-10 and TGF-β but not by IL-17 or IFN-γ and was associated with a decrease in the expression of HC-10-reactive molecules. The cytokines IL-10 and TGF-β potentiate the proliferative capacity that IL-15 has on human T cells in vitro, an effect that is associated with a reduction in the amount of HC-10 reactive HLA class I molecules induced by IL-15.

Biopotency and surrogate assays to validate the immunomodulatory potency of extracellular vesicles derived from mesenchymal stem/stromal cells for the treatment of experimental autoimmune uveitis

Extracellular vesicles (EVs) derived from mesenchymal stem/stromal cells (MSCs) have been recognized as promising cytotherapeutics due to their demonstrated immunomodulatory effects in various preclinical models. The immunomodulatory capabilities of EVs stem from the proteins and genetic materials they carry from parent cells, but the cargo contents of EVs are significantly influenced by MSC tissues and donors, cellular age and culture conditions, resulting in functional variations. However, there are no surrogate assays available to validate the immunomodulatory potency of MSC-EVs before in vivo administration. In previous work, we discovered that microcarrier culture conditions enhance the immunomodulatory function of MSC-EVs, as well as the levels of immunosuppressive molecules such as TGF-β1 and let-7b in MSC-EVs. Building on these findings, we investigated whether TGF-β1 levels in MSC-EVs could serve as a surrogate biomarker for predicting their potency in vivo. Our studies revealed a strong correlation between TGF-β1 and let-7b levels in MSC-EVs, as well as their capacity to suppress IFN-γ secretion in stimulated splenocytes, establishing biopotency and surrogate assays for MSC-EVs. Subsequently, we validated MSC-EVs generated from monolayer cultures (ML-EVs) or microcarrier cultures (MC-EVs) using murine models of experimental autoimmune uveoretinitis (EAU) and additional in vitro assays reflecting the Mode of Action of MSC-EVs in vivo. Our findings demonstrated that MC-EVs carrying high levels of TGF-β1 exhibited greater efficacy than ML-EVs in halting disease progression in mice with EAU as well as inducing apoptosis and inhibiting the chemotaxis of retina-reactive T cells. Additionally, MSC-EVs suppressed the MAPK/ERK pathway in activated T cells, with treatment using TGF-β1 or let-7b showing similar effects on the MAPK/ERK pathway. Collectively, our data suggest that MSC-EVs directly inhibit the infiltration of retina-reactive T cells toward the eyes, thereby halting the disease progression in EAU mice, and their immunomodulatory potency in vivo can be predicted by their TGF-β1 levels.

Defining Human Regulatory T Cells beyond FOXP3: The Need to Combine Phenotype with Function

Regulatory T cells (Tregs) are essential to maintain immune homeostasis by promoting self-tolerance. Reduced Treg numbers or functionality can lead to a loss of tolerance, increasing the risk of developing autoimmune diseases. An overwhelming variety of human Tregs has been described, based on either specific phenotype, tissue compartment, or pathological condition, yet the bulk of the literature only addresses CD25-positive and CD127-negative cells, coined by naturally occurring Tregs (nTregs), most of which express the transcription factor Forkhead box protein 3 (FOXP3). While the discovery of FOXP3 was seminal to understanding the origin and biology of nTregs, there is evidence in humans that not all T cells expressing FOXP3 are regulatory, and that not all Tregs express FOXP3. Namely, the activation of human T cells induces the transient expression of FOXP3, irrespective of whether they are regulatory or inflammatory effectors, while some induced T cells that may be broadly defined as Tregs (e.g., Tr1 cells) typically lack demethylation and do not express FOXP3. Furthermore, it is unknown whether and how many nTregs exist without FOXP3 expression. Several other candidate regulatory molecules, such as GITR, Lag-3, GARP, GPA33, Helios, and Neuropilin, have been identified but subsequently discarded as Treg-specific markers. Multiparametric analyses have uncovered a plethora of Treg phenotypes, and neither single markers nor combinations thereof can define all and only Tregs. To date, only the functional capacity to inhibit immune responses defines a Treg and distinguishes Tregs from inflammatory T cells (Teffs) in humans. This review revisits current knowledge of the Treg universe with respect to their heterogeneity in phenotype and function. We propose that it is unavoidable to characterize human Tregs by their phenotype in combination with their function, since phenotype alone does not unambiguously define Tregs. There is an unmet need to align the expression of specific markers or combinations thereof with a particular suppressive function to coin functional Treg entities and categorize Treg diversity.

TGF-β signaling in health, disease, and therapeutics

Transforming growth factor (TGF)-β is a multifunctional cytokine expressed by almost every tissue and cell type. The signal transduction of TGF-β can stimulate diverse cellular responses and is particularly critical to embryonic development, wound healing, tissue homeostasis, and immune homeostasis in health. The dysfunction of TGF-β can play key roles in many diseases, and numerous targeted therapies have been developed to rectify its pathogenic activity. In the past decades, a large number of studies on TGF-β signaling have been carried out, covering a broad spectrum of topics in health, disease, and therapeutics. Thus, a comprehensive overview of TGF-β signaling is required for a general picture of the studies in this field. In this review, we retrace the research history of TGF-β and introduce the molecular mechanisms regarding its biosynthesis, activation, and signal transduction. We also provide deep insights into the functions of TGF-β signaling in physiological conditions as well as in pathological processes. TGF-β-targeting therapies which have brought fresh hope to the treatment of relevant diseases are highlighted. Through the summary of previous knowledge and recent updates, this review aims to provide a systematic understanding of TGF-β signaling and to attract more attention and interest to this research area.

A novel GPI-anchored dominant-negative TGF-β receptor II renders T cells unresponsive to TGF-β signaling

Transforming growth factor β (TGF-β) is a pleiotropic cytokine expressed by a wide range of cell types and is known for hampering the effectiveness of cancer immune cell therapeutic approaches. We have designed a novel construct containing the extracellular domain of the TGF-β receptor II linked to a glycosylphosphatidylinositol (GPI) anchor (GPI-ecto-TβRII) lacking the transmembrane and cytoplasmic signaling domain of TGF-β receptor II (TβRII). T cells transduced with lentivirus expressing the GPI-ecto-TβRII construct show 5 to 15 times higher membrane expression compared with a previously established dominant-negative receptor carrying a truncated signaling domain. GPI-ecto-TβRII expression renders T cells unresponsive to TGF-β-induced signaling seen by a lack of SMAD phosphorylation upon exogeneous TGF-β treatment. Transduced T cells continue to express high levels of IFNγ and granulocyte-macrophage colony-stimulating factor (GM-CSF), among other cytokines, in the presence of TGF-β while cytokine expression in untransduced T cells is being markedly suppressed. Furthermore, T cells expressing GPI-ecto-TβRII constructs have been shown to efficiently capture and inactivate TGF-β from their environment. These results indicate the potential benefits of GPI-ecto-TβRII expressing cytotoxic T cells (CTLs) in future cell therapies.

TGF-β broadly modifies rather than specifically suppresses reactivated memory CD8 T cells in a dose-dependent manner

Transforming growth factor β (TGF-β) directly acts on naive, effector, and memory T cells to control cell fate decisions, which was shown using genetic abrogation of TGF-β signaling. TGF-β availability is altered by infections and cancer; however, the dose-dependent effects of TGF-β on memory CD8 T cell (Tmem) reactivation are still poorly defined. We examined how activation and TGF-β signals interact to shape the functional outcome of Tmem reactivation. We found that TGF-β could suppress cytotoxicity in a manner that was inversely proportional to the strength of the activating TCR or proinflammatory signals. In contrast, even high doses of TGF-β had a comparatively modest effect on IFN-γ expression in the context of weak and strong reactivation signals. Since CD8 Tmem may not always receive TGF-β signals concurrently with reactivation, we also explored whether the temporal order of reactivation versus TGF-β signals is of importance. We found that exposure to TGF-β before or after an activation event were both sufficient to reduce cytotoxic effector function. Concurrent ATAC-seq and RNA-seq analysis revealed that TGF-β altered ~10% of the regulatory elements induced by reactivation and also elicited transcriptional changes indicative of broadly modulated functional properties. We confirmed some changes on the protein level and found that TGF-β-induced expression of CCR8 was inversely proportional to the strength of the reactivating TCR signal. Together, our data suggest that TGF-β is not simply suppressing CD8 Tmem but modifies functional and chemotactic properties in context of their reactivation signals and in a dose-dependent manner.

Replication of infectious bronchitis virus (IBV) Delmarva (DMV)/1639 variant in primary and secondary lymphoid organs leads to immunosuppression in chickens

Infectious bronchitis virus (IBV) that primarily causes respiratory infection in chickens, disseminate to multiple body systems leading to pathology, results in economic losses to poultry industry. IBV replicates in the bursa of Fabricius (BF), Harderian gland (HG), cecal tonsils (CT), and spleen. The objective of this study was to investigate the immunosuppressive effect of IBV Delmarva (DMV/1639) variant in chickens. Specific pathogen free chickens were infected with the IBV DMV/1639 variant while maintaining an age-matched uninfected control group. At predetermined time points, subsets of the infected and control chickens were observed for changes in body weights and pathological changes. The histopathological lesions were observed in the CT and BF, with minimal lesions in the thymus and spleen. The mRNA expression of pro-inflammatory mediators suggested immunomodulation by IBV, favoring viral replication. Further studies are warranted to observe the functional impact of the IBV DMV/1639 variant's replication in immune organs.

TGF-β broadly modifies rather than specifically suppresses reactivated memory CD8 T cells in a dose-dependent manner

Transforming growth factor β (TGF-β) directly acts on naïve, effector and memory T cells to control cell fate decisions, which was shown using genetic abrogation of TGF-β signaling. TGF-β availability is altered by infections and cancer, however the dose-dependent effects of TGF-β on memory CD8 T cell (Tmem) reactivation are still poorly defined. We examined how activation and TGF-β signals interact to shape the functional outcome of Tmem reactivation. We found that TGF-β could suppress cytotoxicity in a manner that was inversely proportional to the strength of the activating TCR or pro-inflammatory signals. In contrast, even high doses of TGF-β had a comparatively modest effect on IFN-γ expression in the context of weak and strong reactivation signals. Since CD8 Tmem may not always receive TGF-β signals concurrently with reactivation, we also explored whether the temporal order of reactivation versus TGF-β signals is of importance. We found that exposure to TGF-β prior to as well as after an activation event were both sufficient to reduce cytotoxic effector function. Concurrent ATAC-seq and RNA-seq analysis revealed that TGF-β altered ~10% of the regulatory elements induced by reactivation and also elicited transcriptional changes indicative of broadly modulated functional properties. We confirmed some changes on the protein level and found that TGF-β-induced expression of CCR8 was inversely proportional to the strength of the reactivating TCR signal. Together, our data suggest that TGF-β is not simply suppressing CD8 Tmem, but modifies functional and chemotactic properties in context of their reactivation signals and in a dose-dependent manner.

Steroid receptor coactivator 3 is a key modulator of regulatory T cell-mediated tumor evasion

Steroid receptor coactivator 3 (SRC-3) is most strongly expressed in regulatory T cells (Tregs) and B cells, suggesting that it plays an important role in the regulation of Treg function. Using an aggressive E0771 mouse breast cell line syngeneic immune-intact murine model, we observed that breast tumors were "permanently eradicated" in a genetically engineered tamoxifen-inducible Treg-cell-specific SRC-3 knockout (KO) female mouse that does not possess a systemic autoimmune pathological phenotype. A similar eradication of tumor was noted in a syngeneic model of prostate cancer. A subsequent injection of additional E0771 cancer cells into these mice showed continued resistance to tumor development without the need for tamoxifen induction to produce additional SRC-3 KO Tregs. SRC-3 KO Tregs were highly proliferative and preferentially infiltrated into breast tumors by activating the chemokine (C-C motif) ligand (Ccl) 19/Ccl21/chemokine (C-C motif) receptor (Ccr)7 signaling axis, generating antitumor immunity by enhancing the interferon-γ/C-X-C motif chemokine ligand (Cxcl) 9 signaling axis to facilitate the entrance and function of effector T cells and natural killer cells. SRC-3 KO Tregs also show a dominant effect by blocking the immune suppressive function of WT Tregs. Importantly, a single adoptive transfer of SRC-3 KO Tregs into wild-type E0771 tumor-bearing mice can completely abolish preestablished breast tumors by generating potent antitumor immunity with a durable effect that prevents tumor reoccurrence. Therefore, treatment with SRC-3-deleted Tregs represents an approach to completely block tumor growth and recurrence without the autoimmune side effects that typically accompany immune checkpoint modulators.

Phenotypic plasticity and reduced tissue retention of exhausted tumor-infiltrating T cells following neoadjuvant immunotherapy in head and neck cancer

Neoadjuvant immunotherapies (NITs) have led to clinical benefits in several cancers. Characterization of the molecular mechanisms underlying responses to NIT may lead to improved treatment strategies. Here we show that exhausted, tumor-infiltrating CD8+ T (Tex) cells display local and systemic responses to concurrent neoadjuvant TGF-β and PD-L1 blockade. NIT induces a significant and selective increase in circulating Tex cells associated with reduced intratumoral expression of the tissue-retention marker CD103. TGF-β-driven CD103 expression on CD8+ T cells is reversed following TGF-β neutralization in vitro, implicating TGF-β in T cell tissue retention and impaired systemic immunity. Transcriptional changes implicate T cell receptor signaling and glutamine metabolism as important determinants of enhanced or reduced Tex treatment response, respectively. Our analysis illustrates physiological and metabolic changes underlying T cell responses to NIT, highlighting the interplay between immunosuppression, tissue retention, and systemic anti-tumor immunity and suggest antagonism of T cell tissue retention as a promising neoadjuvant treatment strategy.

Inhibition of non-receptor tyrosine kinase LCK partially mitigates mixed granulocytic airway inflammation in a murine model of asthma

Asthma affects millions of people worldwide and is one of the most common inflammatory airway diseases. Asthma phenotypes are quite complex and categorized as eosinophilic, mixed granulocytic (presence of both eosinophils and neutrophils in the airways) and neutrophilic. Mixed granulocytic asthma requires large doses of inhaled corticosteroids, which are often insufficient in controlling airway inflammation. Therefore, there is a medical need to test newer therapies to control granulocytic inflammation. Lymphocyte specific protein tyrosine kinase (LCK) signaling has gained momentum in recent years as a molecular target in inflammatory diseases such as asthma. LCK is expressed in lymphocytes and is required for inflammatory intracellular signaling in response to antigenic stimulation. Therefore, efficacy of LCK inhibitor, A770041 was tested in cockroach (CE)-induced corticosteroid insensitive murine model of asthma. The effect of LCK inhibitor was investigated on granulocytic airway inflammation, mucus production, p-LCK and downstream signaling molecules such as p-PLCγ, GATA3, p-STAT3 in CD4+ T cells. Moreover, its effects were also studied on Th2/Th17 related cytokines and oxidative stress parameters (iNOS/nitrotyrosine) in neutrophils/macrophages. Our study shows that CE-induced p-LCK levels are concomitant with increased neutrophilic/eosinophilic inflammation and mucus hypersecretion which are significantly mitigated by A770041 treatment. A770041 also caused marked attenuation of CE-induced pulmonary levels of IL-17A levels but not completely. However, A770041 in combination with dexamethasone caused complete downregulation of mixed granulocytic airway inflammation as well as Th2/Th17 related immune responses. These results suggest that combination of LCK inhibition along with corticosteroids may be pursued as an alternative strategy to completely treat mixed granulocytic asthma.

Steroid Receptor Coactivator-3 is a Key Modulator of Regulatory T Cell-Mediated Tumor Evasion

Steroid receptor coactivator 3 (SRC-3) is most strongly expressed in regulatory T cells (Tregs) and B cells, suggesting that it plays an important role in the regulation of Treg function. Using an aggressive E0771 mouse breast cell line syngeneic immune-intact murine model, we observed that breast tumors were 'permanently eradicated' in a genetically engineered tamoxifen-inducible Treg-cell specific SRC-3 knockout (KO) female mouse that does not possess a systemic autoimmune pathological phenotype. A similar eradication of tumor was noted in a syngeneic model of prostate cancer. A subsequent injection of additional E0771 cancer cells into these mice showed continued resistance to tumor development without the need for tamoxifen induction to produce additional SRC-3 KO Tregs. SRC-3 KO Tregs were highly proliferative and preferentially infiltrated into breast tumors by activating the Chemokine (C-C motif) ligand (Ccl) 19/Ccl21/ Chemokine (C-C motif) Receptor (Ccr)7 signaling axis, generating antitumor immunity by enhancing the interferon-γ/C-X-C Motif Chemokine Ligand (Cxcl) 9 signaling axis to facilitate the entrance and function of effector T cells and Natural Killer cells. SRC-3 KO Tregs also show a dominant effect by blocking the immune suppressive function of WT Tregs. Importantly, a single adoptive transfer of SRC-3 KO Tregs into wild-type E0771 tumor-bearing mice can completely abolish pre-established breast tumors by generating potent antitumor immunity with a durable effect that prevents tumor reoccurrence. Therefore, treatment with SRC-3 deleted Tregs represents a novel approach to completely block tumor growth and recurrence without the autoimmune side-effects that typically accompany immune checkpoint modulators.

Significance statement

Tregs are essential in restraining immune responses for immune homeostasis. SRC-3 is a pleiotropic coactivator, the second-most highly expressed transcriptional coactivator in Tregs, and a suspect in Treg function. The disruption of SRC-3 expression in Tregs leads to a 'complete lifetime eradication' of tumors in aggressive syngeneic breast cancer mouse models because deletion of SRC-3 alters the expression of a wide range of key genes involved in efferent and afferent Treg signaling. SRC-3KO Tregs confer this long-lasting protection against cancer recurrence in mice without an apparent systemic autoimmune pathological phenotype. Therefore, treatment with SRC-3 deleted Tregs could represent a novel and efficient future target for eliminating tumor growth and recurrence without the autoimmune side-effects that typically accompany immune checkpoint modulators.

Rebalancing TGFβ1/BMP signals in exhausted T cells unlocks responsiveness to immune checkpoint blockade therapy

T cell dysfunctionality prevents the clearance of chronic infections and cancer. Furthermore, epigenetic programming in dysfunctional CD8+ T cells limits their response to immunotherapies, including immune checkpoint blockade (ICB). However, it is unclear which upstream signals drive acquisition of dysfunctional epigenetic programs, and whether therapeutically targeting these signals can remodel terminally dysfunctional T cells to an ICB-responsive state. Here we innovate an in vitro model system of stable human T cell dysfunction and show that chronic TGFβ1 signaling in posteffector CD8+ T cells accelerates their terminal dysfunction through stable epigenetic changes. Conversely, boosting bone morphogenetic protein (BMP) signaling while blocking TGFβ1 preserved effector and memory programs in chronically stimulated human CD8+ T cells, inducing superior responses to tumors and synergizing the ICB responses during chronic viral infection. Thus, rebalancing TGFβ1/BMP signals provides an exciting new approach to unleash dysfunctional CD8+ T cells and enhance T cell immunotherapies.

IL-10 Negatively Controls the Primary T Cell Response of Tilapia by Triggering the JAK1/STAT3/SOCS3 Axis That Suppresses NF-κB and MAPK/ERK Signaling

The braking mechanisms to protect the host from tissue damage and inflammatory disease caused by an overexuberant immune response are common in many T cell subsets. However, the negative regulation of T cell responses and detailed mechanisms are not well understood in early vertebrates. In the current study, using a Nile tilapia (Oreochromis niloticus) model, we investigated the suppression of T cell immunity by IL-10. Tilapia encodes an evolutionarily conserved IL-10, whose expression in lymphocytes is markedly induced during the primary adaptive immune response against Aeromonas hydrophila infection. Activated T cells of tilapia produce IL-10, which in turn inhibits proinflammatory cytokine expression and suppresses PHA-induced T cell activation. Moreover, administration of IL-10 impairs the proliferation of tilapia T cells, reduces their potential to differentiate into Th subsets, and cripples the cytotoxic function, rendering the animals more vulnerable to pathogen attack. After binding to its receptor IL-10Ra, IL-10 activates the JAK1/STAT3 axis by phosphorylation and enhances the expression of the suppressor of cytokine signaling 3 (SOCS3), which in turn attenuates the activation of the NF-κB and MAPK/ERK signaling pathways, thus suppressing the T cell response of tilapia. Our findings elucidate a negative regulatory mechanism of T cell immunity in a fish species and support the notion that the braking mechanism of T cells executed through IL-10 existed prior to the divergence of the tetrapod lineage from teleosts. Therefore, this study, to our knowledge, provides a novel perspective on the evolution of the adaptive immune system.

Targeting TGF-β signaling in the multiple myeloma microenvironment: Steering CARs and T cells in the right direction

Multiple myeloma (MM) remains a lethal hematologic cancer characterized by the expansion of transformed plasma cells within the permissive bone marrow (BM) milieu. The emergence of relapsed and/or refractory MM (RRMM) is provoked through clonal evolution of malignant plasma cells that harbor genomic, metabolic and proteomic perturbations. For most patients, relapsed disease remains a major cause of overall mortality. Transforming growth factors (TGFs) have pleiotropic effects that regulate myelomagenesis as well as the emergence of drug resistance. Moreover, TGF-β modulates numerous cell types present with the tumor microenvironment, including many immune cell types. While numerous agents have been FDA-approved over the past 2 decades and significantly expanded the treatment options available for MM patients, the molecular mechanisms responsible for drug resistance remain elusive. Multiple myeloma is uniformly preceded by a premalignant state, monoclonal gammopathy of unknown significance, and both conditions are associated with progressive deregulation in host immunity characterized by reduced T cell, natural killer (NK) cell and antigen-presenting dendritic cell (DC) activity. TGF-β promotes myelomagenesis as well as intrinsic drug resistance by repressing anti-myeloma immunity to promote tolerance, drug resistance and disease progression. Hence, repression of TGF-β signaling is a prerequisite to enhance the efficacy of current and future immunotherapeutics. Novel strategies that incorporate T cells that have been modified to express chimeric antigen receptor (CARs), T cell receptors (TCRs) and bispecific T cell engagers (BiTEs) offer promise to block TGF-β signaling, overcome chemoresistance and enhance anti-myeloma immunity. Here, we describe the effects of TGF-β signaling on immune cell effectors in the bone marrow and emerging strategies to overcome TGF-β-mediated myeloma growth, drug resistance and survival.

Combined targeting of soluble latent TGF-ß and a solid tumor-associated antigen with adapter CAR T cells

Solid tumors consist of malignant and nonmalignant cells that together create the local tumor microenvironment (TME). Additionally, the TME is characterized by the expression of numerous soluble factors such as TGF-β. TGF-β plays an important role in the TME by suppressing T cell effector function and promoting tumor invasiveness. Up to now CAR T cells exclusively target tumor-associated antigens (TAA) located on the cell membrane. Thus, strategies to exploit soluble antigens as CAR targets within the TME are needed. This study demonstrates a novel approach using Adapter CAR (AdCAR) T cells for the detection of soluble latent TGF-β within the TME of a pancreatic tumor model. We show that AdCARs in combination with the respective adapter can be used to sense soluble tumor-derived latent TGF-β, both in vitro and in vivo. Sensing of the soluble antigen induced cellular activation and effector cytokine production in AdCAR T cells. Moreover, we evaluated AdCAR T cells for the combined targeting of soluble latent TGF-β and tumor cell killing by targeting CD66c as TAA in vivo. In sum, our study broadens the spectrum of targetable moieties for AdCAR T cells by soluble latent TGF-β.

Therapeutic Effect of IL-21 Blockage by Gene Therapy in Experimental Autoimmune Encephalomyelitis

The pathogenic role of the interleukin 21 (IL-21) in different autoimmune diseases, such as multiple sclerosis (MS), has been extensively studied. However, its pleiotropic nature makes it a cytokine that may exhibit different activity depending on the immunological stage of the disease. In this study, we developed a gene therapy strategy to block the interaction between IL-21 and its receptor (IL-21R) by using adeno-associated vectors (AAV) encoding a new soluble cytokine receptor (sIL21R) protein. We tested this strategy in a murine model of experimental autoimmune encephalomyelitis (EAE), obtaining different clinical effects depending on the time at which the treatment was applied. Although the administration of the treatment during the development of the immune response was counterproductive, the preventive administration of the therapeutic vectors showed a protective effect by reducing the number of animals that developed the disease, as well as an improvement at the histopathological level and a modification of the immunological profile of the animals treated with the AAV8.sIL21R. The beneficial effect of the treatment was also observed when inducing the expression of the therapeutic molecule once the first neurological signs were established in a therapeutic approach with a doxycyline (Dox)-inducible expression system. All these clinical results highlight the pleiotropicity of this cytokine in the different clinical stages and its key role in the EAE immunopathogenesis.

Fucoxanthin Prevents the Ovalbumin-Induced Food Allergic Response by Enhancing the Intestinal Epithelial Barrier and Regulating the Intestinal Flora

This study aimed to determine whether fucoxanthin alleviated ovalbumin (OVA)-induced food allergy (FA) and explored the possible mechanisms. The results indicated that supplementation with fucoxanthin at 10.0-20.0 mg/kg per day for 7 weeks inhibited food anaphylaxis and the production of immunoglobulin (Ig) E, IgG, histamine, and related cytokines while alleviating allergic symptoms in sensitized mice. Fucoxanthin enhanced the intestinal epithelial barrier by up-regulating tight junction (TJ) protein expression and promoting regenerating islet-derived protein III-gamma (RegIIIγ) and secretory IgA (sIgA) secretion. In addition, fucoxanthin induced the secretion of anti-inflammatory factors (interleukin (IL)-10 and transforming growth factor β (TGF-β)) by regulatory T (Treg) cells and decreased the pro-inflammatory factor levels (IL-4, tumor necrosis factor-α (TNF-α), IL-17, and IL-1β), ameliorating intestinal inflammation. Compared with the model group, beneficial bacteria, such as Lactobacillaceae, increased in the intestinal flora, while pathogenic bacteria like Helicobacteraceae, Desulfovibrionaceae, and Streptococcaceae decreased. Therefore, fucoxanthin may effectively prevent FA by enhancing the intestinal epithelial barrier and reshaping the intestinal flora.

An immune-inflamed tumor microenvironment as defined by CD8 score is associated with favorable oncologic outcomes in hepatocellular carcinoma independent of measures of tumor mutational burden

Despite low mutational burden, immune checkpoint inhibitors have demonstrated promising results in a significant minority of hepatocellular carcinoma (HCC) patients with advanced disease. We hypothesized that HCC patients with higher levels of CD8+ T cell infiltration reflect an immune-inflamed cohort which has improved oncologic outcomes. 355 HCC patients with clinical and transcriptome data in the Cancer Genome Atlas (TCGA) and 151 HCC patients from cohort GSE7624 were analyzed. xCell computational algorithm was used to analyze immune cell infiltration in these patients. Each cohort was divided into high and low expression by the highest 2 terciles value. Gene Set Enrichment Analysis was performed to identify enriched gene sets. High CD8 score associated with improved overall survival in both cohorts (both P < 0.05). High score correlates with early BCLC stage (P = 0.035) but not AJCC stage. High CD8 also correlated with increased IFN-γ response (p = 0.038), lymphocyte infiltration (P < 0.001), and leukocyte fraction (P < 0.001). It was associated with increased polyclonality of T cell (P < 0.001) and B cell response (P = 0.017). High CD8 score correlated with increased cytolytic activity score (P < 0.001) and expression of multiple immune checkpoints including PD-1, PD-L1, CTLA-4 and Lag3 (all P < 0.001). There was no correlation to tumor mutational burden and neoantigens. GSEA demonstrated upregulation of several gene sets involved in inflammatory response and IFN-γ response. In conclusion, HCC patients with high CD8 score demonstrated favorable oncologic outcomes, which may be due to immune-mediated tumor cell attack. Furthermore, CD8 score may be a potentially useful biomarker to select patients for immune checkpoint inhibition.

SOX4-mediated FBW7 transcriptional upregulation confers Tamoxifen resistance in ER+ breast cancers via GATA3 downregulation

AIM

Tamoxifen-mediated endocrine therapy has been standard treatment for ER+ breast cancers; however, majority of them acquire resistance leading to disease relapse. Although numerous substrates of E3 ligase FBW7 are known, only a handful of factors that regulate FBW7 expression and function are reported. In particular, there remains a lack of in-depth understanding of FBW7 transcriptional regulation.

MATERIALS AND METHODS

Luciferase reporter assay was performed after cloning full length and truncated FBW7 promoters followed by Chromatin immunoprecipitation assay to validate binding of SOX4 on FBW7 promoter. Transcriptional regulation of FBW7 by SOX4 and their biological consequences with respect to ER+ breast cancer was then evaluated using immunoblotting and other cell based assays.

KEY FINDINGS

SOX4 positively regulates FBW7 at transcriptional level by binding to three putative SOX4 biding sites within 3.1 kb long FBW7 promoter. Analysis of publicly available RNAseq datasets also showed a positive correlation between SOX4 and FBW7 mRNA in cancer cell lines and patient samples. qPCR and Immunoblotting confirmed that transiently or stably expressed SOX4 induced both endogenous FBW7 mRNA and protein levels. Our findings further demonstrated that increased levels of SOX4 and FBW7 in MCF7 mammospheres promoted cancer stemness and tumor cell dormancy. We further showed that both MCF7 mammospheres and MCF^TAMR cells had elevated SOX4 levels which apparently enhanced FBW7 to potentiate GATA3 degradation leading to enhanced stemness, tumor dormancy and Tamoxifen resistance in MCF7^TAMR as well as patients with ER+ breast cancers.

SIGNIFICANCE

Targeting SOX4-FBW7-GATA3 axis may overcome tamoxifen resistance in ER+ breast cancers.

The solid tumor microenvironment-Breaking the barrier for T cells: How the solid tumor microenvironment influences T cells: How the solid tumor microenvironment influences T cells

The tumor microenvironment (TME) plays a pivotal role in the behavior and development of solid tumors as well as shaping the immune response against them. As the tumor cells proliferate, the space they occupy and their physical interactions with the surrounding tissue increases. The growing tumor tissue becomes a complex dynamic structure, containing connective tissue, vascular structures, and extracellular matrix (ECM) that facilitates stimulation, oxygenation, and nutrition, necessary for its fast growth. Mechanical cues such as stiffness, solid stress, interstitial fluid pressure (IFP), matrix density, and microarchitecture influence cellular functions and ultimately tumor progression and metastasis. In this fight, our body is equipped with T cells as its spearhead against tumors. However, the altered biochemical and mechanical environment of the tumor niche affects T cell efficacy and leads to their exhaustion. Understanding the mechanobiological properties of the TME and their effects on T cells is key for developing novel adoptive tumor immunotherapies.

Immune Inhibitory Properties and Therapeutic Prospects of Transforming Growth Factor-Beta and Interleukin 10 in Autoimmune Hepatitis

Transforming growth factor-beta and interleukin 10 have diverse immune inhibitory properties that have restored homeostatic defense mechanisms in experimental models of autoimmune disease. The goals of this review are to describe the actions of each cytokine, review their investigational use in animal models and patients, and indicate their prospects as interventions in autoimmune hepatitis. English abstracts were identified in PubMed by multiple search terms. Full-length articles were selected for review, and secondary and tertiary bibliographies were developed. Transforming growth factor-beta expands the natural and inducible populations of regulatory T cells, limits the proliferation of natural killer cells, suppresses the activation of naïve CD8⁺ T cells, decreases the production of interferon-gamma, and stimulates fibrotic repair. Interleukin 10 selectively inhibits the CD28 co-stimulatory signal for antigen recognition and impairs antigen-specific activation of uncommitted CD4⁺ and CD8⁺ T cells. It also inhibits maturation of dendritic cells, suppresses Th17 cells, supports regulatory T cells, and limits production of diverse pro-inflammatory cytokines. Contradictory immune stimulatory effects have been associated with each cytokine and may relate to the dose and accompanying cytokine milieu. Experimental findings have not translated into successful early clinical trials. The recombinant preparation of each agent in low dosage has been safe in human studies. In conclusion, transforming growth factor-beta and interleukin 10 have powerful immune inhibitory actions of potential therapeutic value in autoimmune hepatitis. The keys to their therapeutic application will be to match their predominant non-redundant function with the pivotal pathogenic mechanism or cytokine deficiency and to avoid contradictory immune stimulatory actions.

Myeloid-Derived Suppressor Cells: A Multifaceted Accomplice in Tumor Progression

Myeloid-derived suppressor cell (MDSC) is a heterogeneous population of immature myeloid cells, has a pivotal role in negatively regulating immune response, promoting tumor progression, creating pre-metastases niche, and weakening immunotherapy efficacy. The underlying mechanisms are complex and diverse, including immunosuppressive functions (such as inhibition of cytotoxic T cells and recruitment of regulatory T cells) and non-immunological functions (mediating stemness and promoting angiogenesis). Moreover, MDSC may predict therapeutic response as a poor prognosis biomarker among multiple tumors. Accumulating evidence indicates targeting MDSC can reverse immunosuppressive tumor microenvironment, and improve therapeutic response either single or combination with immunotherapy. This review summarizes the phenotype and definite mechanisms of MDSCs in tumor progression, and provide new insights of targeting strategies regarding to their clinical applications.

Overcoming TGFβ-mediated immune evasion in cancer

Transforming growth factor-β (TGFβ) signalling controls multiple cell fate decisions during development and tissue homeostasis; hence, dysregulation of this pathway can drive several diseases, including cancer. Here we discuss the influence that TGFβ exerts on the composition and behaviour of different cell populations present in the tumour immune microenvironment, and the context-dependent functions of this cytokine in suppressing or promoting cancer. During homeostasis, TGFβ controls inflammatory responses triggered by exposure to the outside milieu in barrier tissues. Lack of TGFβ exacerbates inflammation, leading to tissue damage and cellular transformation. In contrast, as tumours progress, they leverage TGFβ to drive an unrestrained wound-healing programme in cancer-associated fibroblasts, as well as to suppress the adaptive immune system and the innate immune system. In consonance with this key role in reprogramming the tumour microenvironment, emerging data demonstrate that TGFβ-inhibitory therapies can restore cancer immunity. Indeed, this approach can synergize with other immunotherapies - including immune checkpoint blockade - to unleash robust antitumour immune responses in preclinical cancer models. Despite initial challenges in clinical translation, these findings have sparked the development of multiple therapeutic strategies that inhibit the TGFβ pathway, many of which are currently in clinical evaluation.

Honeysuckle-derived microRNA2911 inhibits tumor growth by targeting TGF-β1

Background

Honeysuckle is a time‐honored herb with anticancer activity in traditional Chinese medicine. Recently, accumulating reports are suggesting that the microRNAs in this medicinal plant not only play a physiological role in their original system, but also can be transmitted to another species as potential therapeutic components. In the numerous bioactive investigations, the anti-tumor effects of these microRNAs in the magical herb are rarely studied, especially the special miR2911, a honeysuckle-encoded atypical microRNA, with high stability during the boiling process and unique biological activity to target TGF-β1 mRNA.

Methods

Luciferase assay was conducted to test the ability of miR2911 to target TGF-β1 mRNA. ELISA was performed to determine the expression level of TGF-β1 of mouse colorectal adenocarcinoma CT26 cells when treated with miR2911 and tumor tissue in Sidt1^+/+ and Sidt1^−/− mice. qRT-PCR was performed to examine the level of expression of miR2911. Tumor-bearing wild and nude mice were employed to evaluate the anti-tumor effect of honeysuckle and miR2911 in vivo. Tumor tissue necrosis was observed by H&E staining. Besides, the infiltration of T lymphocytes across solid tumors was tested by immunostaining staining.

Results

Our results showed that honeysuckle slowed the development of colon cancer down. Further research showed that miR2911 could bind strongly to TGF-β1 mRNA and down-regulate the expression of TGF-β1 and had a high stability under boiling and acid condition. Moreover, SIDT1 mediated dietary miR2911 inter-species absorption. And we found that miR2911 had a similar anticancer effect as honeysuckle. Mechanistically, miR2911 reversed the tumor-promoting effect of TGF-β1 by an increase of T lymphocytes infiltration, resulting in slowing the colon cancer process in immunocompetent mice. Consistent with this inference, the anti-tumor effect of miR2911 was revealed to be abolished in T cell immune deficiency mice.

Conclusion

Taken together, honeysuckle-derived miR2911 showed an anti-tumor effect in colon cancer through targeting TGF-β1 mRNA. The down-regulation of TGF-β1 promoted T lymphocytes infiltration, and accordingly impeded the colon tumor development.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00453-y.

Armored CAR T-Cells: The Next Chapter in T-Cell Cancer Immunotherapy

Chimeric antigen receptor (CAR) T-cell therapy engineers T-cells to express a synthetic receptor which redirects effector function to the tumor, to improve efficacy and reduce toxicities associated with conventional treatments, such as radiotherapy and chemotherapy. This approach has proved effective in treating hematological malignancies; however, the same effects have not been observed in solid tumors. The immunosuppressive tumor microenvironment (TME) creates a significant barrier to solid tumor efficacy and reduces the anti-cancer activity of endogenous tumor-resident immune cells, enabling cancer progression. In recent years, researchers have attempted to enhance CAR T-cell function in the TME by engineering the cells to express various proteins alongside the CAR. Examples of this engineering include inducing CAR T-cells to secrete cytokines or express cytokine receptors to modulate the cytokine milieu of the TME. Alternatively, the CAR T-cell may secrete antibody-like proteins to target a range of tumor antigens. Collectively, these methods are termed armored CAR T-cell therapy, and in this review, we will discuss the range of armored CAR T-cell approaches which have been investigated to date.

Transforming growth factor-beta1 and myeloid-derived suppressor cells: A cancerous partnership

Transforming growth factor-beta1 (TGF-β1) plays a crucial role in tumor progression. It can inhibit early cancer stages but promotes tumor growth and development at the late stages of tumorigenesis. TGF-β1 has a potent immunosuppressive function within the tumor microenvironment that largely contributes to tumor cells' immune escape and reduction in cancer immunotherapy responses. Likewise, myeloid-derived suppressor cells (MDSCs) have been postulated as leading tumor promoters and a hallmark of cancer immune evasion mechanisms. This review attempts to analyze the prominent roles of both TGF-β1 and MDSCs and their interplay in cancer immunity. Furthermore, therapies against either TGF-β1 or MDSCs, and their potential synergistic combination with immunotherapies are discussed. Simultaneous TGF-β1 and MDSCs inhibition suggest a potential improvement in immunotherapy or subverted tumor immune resistance.

Neurokinin-1 Receptor Signaling Is Required for Efficient Ca2+ Flux in T-Cell-Receptor-Activated T Cells

Efficient Ca²⁺ flux induced during cognate T cell activation requires signaling the T cell receptor (TCR) and unidentified G-protein-coupled receptors (GPCRs). T cells express the neurokinin-1 receptor (NK1R), a GPCR that mediates Ca²⁺ flux in excitable and non-excitable cells. However, the role of the NK1R in TCR signaling remains unknown. We show that the NK1R and its agonists, the neuropeptides substance P and hemokinin-1, co-localize within the immune synapse during cognate activation of T cells. Simultaneous TCR and NK1R stimulation is necessary for efficient Ca²⁺ flux and Ca²⁺-dependent signaling that sustains the survival of activated T cells and helper 1 (Th1) and Th17 bias. In a model of contact dermatitis, mice with T cells deficient in NK1R or its agonists exhibit impaired cellular immunity, due to high mortality of activated T cells. We demonstrate an effect of the NK1R in T cells that is relevant for immunotherapies based on pro-inflammatory neuropeptides and its receptors.

The neurokinin 1 receptor (NK1R) induces Ca²⁺ flux in excitable cells. Here, Morelli et al. show that NK1R signaling in T cells promotes optimal Ca²⁺ flux triggered by TCR stimulation, which is necessary to sustain T cell survival and the efficient Th1- and Th17-based immunity that is relevant for immunotherapies based on pro-inflammatory neuropeptides.

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.

The Therapeutic Potential of Regulatory T Cells: Challenges and Opportunities

Regulatory T cells (Tregs) are an immunosuppressive subgroup of CD4+ T cells which are identified by the expression of forkhead box protein P3 (Foxp3). The modulation capacity of these immune cells holds an important role in both transplantation and the development of autoimmune diseases. These cells are the main mediators of self-tolerance and are essential for avoiding excessive immune reactions. Tregs play a key role in the induction of peripheral tolerance that can prevent autoimmunity, by protecting self-reactive lymphocytes from the immune reaction. In contrast to autoimmune responses, tumor cells exploit Tregs in order to prevent immune cell recognition and anti-tumor immune response during the carcinogenesis process. Recently, numerous studies have focused on unraveling the biological functions and principles of Tregs and their primary suppressive mechanisms. Due to the promising and outstanding results, Tregs have been widely investigated as an alternative tool in preventing graft rejection and treating autoimmune diseases. On the other hand, targeting Tregs for the purpose of improving cancer immunotherapy is being intensively evaluated as a desirable and effective method. The purpose of this review is to point out the characteristic function and therapeutic potential of Tregs in regulatory immune mechanisms in transplantation tolerance, autoimmune diseases, cancer therapy, and also to discuss that how the manipulation of these mechanisms may increase the therapeutic options.

TGF-β Mediated Immune Evasion in Cancer-Spotlight on Cancer-Associated Fibroblasts

Various components of the tumor microenvironment (TME) play a critical role in promoting tumorigenesis, progression, and metastasis. One of the primary functions of the TME is to stimulate an immunosuppressive environment around the tumor through multiple mechanisms including the activation of the transforming growth factor-beta (TGF-β) signaling pathway. Cancer-associated fibroblasts (CAFs) are key cells in the TME that regulate the secretion of extracellular matrix (ECM) components under the influence of TGF-β. Recent reports from our group and others have described an ECM-related and CAF-associated novel gene signature that can predict resistance to immune checkpoint blockade (ICB). Importantly, studies have begun to test whether targeting some of these CAF-associated components can be used as a combinatorial approach with ICB. This perspective summarizes recent advances in our understanding of CAF and TGF-β-regulated immunosuppressive mechanisms and ways to target such signaling in cancer.

Roles of TGF-β signaling pathway in tumor microenvirionment and cancer therapy

Transforming growth factor β (TGF- β) signaling pathway has pleiotropic effects on cell proliferation, differentiation, adhesion, senescence, and apoptosis. TGF-β can be widely produced by various immune or non-immune cells and regulate cell behaviors through autocrine and paracrine. It plays essential roles in biological processes including embryological development, immune response, and tumor progression. Few cell signalings can contribute to so many pleiotropic functions as the TGF- β signaling pathway in mammals. The significant function of TGF-β signaling in tumor progression and evasion leading it to draw great attention in scientific and clinical research. Understanding the mechanism of TGF- β signaling provides us with chances to potentiate the effectiveness and selectivity of this therapeutic method. Herein, we review the molecular and cellular mechanisms of TGF-β signaling in carcinomas and tumor microenvironment. Then, we enumerate main achievements of TGF-β blockades used or being evaluated in cancer therapy, providing us opportunities to improve therapeutical approaches in the tumor which thrive in a TGF-β-rich environment.

Pan-TGFβ inhibition by SAR439459 relieves immunosuppression and improves antitumor efficacy of PD-1 blockade

TGFβ is a pleiotropic cytokine that may have both tumor inhibiting and tumor promoting properties, depending on tissue and cellular context. Emerging data support a role for TGFβ in suppression of antitumor immunity. Here we show that SAR439459, a pan-TGFβ neutralizing antibody, inhibits all active isoforms of human and murine TGFβ, blocks TGFβ-mediated pSMAD signaling, and TGFβ-mediated suppression of T cells and NK cells. In vitro, SAR439459 synergized with anti-PD1 to enhance T cell responsiveness. In syngeneic tumor models, SAR439459 treatment impaired tumor growth, while the combination of SAR439459 with anti–PD-1 resulted in complete tumor regression and a prolonged antitumor immunity. Mechanistically, we found that TGFβ inhibition with PD-1 blockade augmented intratumoral CD8⁺ T cell proliferation, reduced exhaustion, evoked proinflammatory cytokines, and promoted tumor-specific CD8⁺ T cell responses. Together, these data support the hypothesis that TGFβ neutralization using SAR439459 synergizes with PD-1 blockade to promote antitumor immunity and formed the basis for the ongoing clinical investigation of SAR439459 in patients with cancer (NCT03192345).

Polymorphisms in the TGFB1 and FOXP3 genes are associated with the presence of antinuclear antibodies in chronic hepatitis C

Chronic infection with Hepacivirus C (HCV) can lead to the occurrence of antinuclear antibodies (ANAs) and changes in cytokine profiles that can be similar to autoimmune diseases. The aim of the study was to identify polymorphisms in important mediators of the immune response in association with ANAs, which could contribute to the development of autoimmunity in hepatitis C. The study included 87 patients with chronic hepatitis C who were evaluated for the presence of ANA (indirect immunofluorescence) and for polymorphisms in the FOXP3, IFNG, IL6, IL8, IL10, MBL2, CRP, TGFΒ1 and TNFA genes (real-time PCR). Of the patients evaluated, 17 (19.54%) had ANA reactivity. The G allele of the FOXP3 rs2232365 polymorphism was more frequent in ANA-positive women (p = 0.0231; OR = 3,285). The C allele of the TGFΒ1 rs1800469 polymorphism was associated with ANA production (p = 0.0169; OR = 2.88). The results suggest that polymorphisms in genes related to immunological regulation may be associated with mechanisms that lead to the emergence of autoantibodies in the context of chronic Hepacivirus C infection.

Downexpression of HSD17B6 correlates with clinical prognosis and tumor immune infiltrates in hepatocellular carcinoma

Background

Hydroxysteroid 17-Beta Dehydrogenase 6 (HSD17B6), a key protein involved in synthetizing dihydrotestosterone, is abundant in the liver. Previous studies have suggested a role for dihydrotestosterone in modulating progress of various malignancies, and HSD17B6 dysfunction was associated with lung cancer and prostate cancer. However, little is known about the detailed role of HSD17B6 in hepatocellular carcinoma (HCC).

Methods

Clinical implication and survival data related to HSD17B6 expression in patients with HCC were obtained through TCGA, ICGC, ONCOMINE, GEO and HPA databases. Survival analysis plots were drawn with Kaplan–Meier Plotter. The ChIP-seq data were obtained from Cistrome DB. Protein–Protein Interaction and gene functional enrichment analyses were performed in STRING database. The correlations between HSD17B6 and tumor immune infiltrates was investigated via TIMER and xCell. The proliferation, migration and invasion of liver cancer cells transfected with HSD17B6 were evaluated by the CCK8 assay, wound healing test and transwell assay respectively. Expression of HSD17B6, TGFB1 and PD-L1 were assessed by quantitative RT-PCR.

Results

HSD17B6 expression was lower in HCC compared to normal liver and correlated with tumor stage and grade. Lower expression of HSD17B6 was associated with worse OS, PFS, RFS and DSS in HCC patients. HNF4A bound to enhancer and promoter regions of HSD17B6 gene, activating its transcription, and DNA methylation of HSD17B6 promoter negatively controlled the expression. HSD17B6 and its interaction partners were involved in androgen metabolism and biosynthesis in liver. HSD17B6 inhibited tumor cell proliferation, migration and invasion in liver cancer cells and low expression of HSD17B6 correlated with high immune cells infiltration, relative reduction of immune responses and multiple immune checkpoint genes expression in HCC, probably by regulating the expression of TGFB1.

Conclusions

This study indicate that HSD17B6 could be a new biomarker for the prognosis of HCC and an important negative regulator of immune responses in HCC.

Transforming growth factor β (TGF-β) receptor signaling regulates kinase networks and phosphatidylinositol metabolism during T-cell activation

The cytokine content in tissue microenvironments shapes the functional capacity of a T cell. This capacity depends on the integration of extracellular signaling through multiple receptors, including the T-cell receptor (TCR), co-receptors, and cytokine receptors. Transforming growth factor β (TGF-β) signals through its cognate receptor, TGFβR, to SMAD family member proteins and contributes to the generation of a transcriptional program that promotes regulatory T-cell differentiation. In addition to transcription, here we identified specific signaling networks that are regulated by TGFβR. Using an array of biochemical approaches, including immunoblotting, kinase assays, immunoprecipitation, and flow cytometry, we found that TGFβR signaling promotes the formation of a SMAD3/4-protein kinase A (PKA) complex that activates C-terminal Src kinase (CSK) and thereby down-regulates kinases involved in proximal TCR activation. Additionally, TGFβR signaling potentiated CSK phosphorylation of the P85 subunit in the P85-P110 phosphoinositide 3-kinase (PI3K) heterodimer, which reduced PI3K activity and down-regulated the activation of proteins that require phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) for their activation. Moreover, TGFβR-mediated disruption of the P85-P110 interaction enabled P85 binding to a lipid phosphatase, phosphatase and tensin homolog (PTEN), aiding in the maintenance of PTEN abundance and thereby promoting elevated PtdIns(4,5)P2 levels in response to TGFβR signaling. Taken together, these results highlight that TGF-β influences the trajectory of early T-cell activation by altering PI3K activity and PtdIns levels.

Transforming Growth Factor-β Signaling in Immunity and Cancer

Transforming growth factor (TGF)-β is a crucial enforcer of immune homeostasis and tolerance, inhibiting the expansion and function of many components of the immune system. Perturbations in TGF-β signaling underlie inflammatory diseases and promote tumor emergence. TGF-β is also central to immune suppression within the tumor microenvironment, and recent studies have revealed roles in tumor immune evasion and poor responses to cancer immunotherapy. Here, we present an overview of the complex biology of the TGF-β family and its context-dependent nature. Then, focusing on cancer, we discuss the roles of TGF-β signaling in distinct immune cell types and how this knowledge is being leveraged to unleash the immune system against the tumor.

TGFβ Programs Central Memory Differentiation in Ex Vivo-Stimulated Human T Cells

The adoptive transfer of ex vivo-expanded T cells is a promising approach to treat several malignancies. Several lines of evidence support that the infusion of T cells with early memory features, capable of expanding and persisting after transfer, are associated with better outcomes. We report herein that exposure to exogenous TGFβ during human T-cell stimulation ex vivo leads to the accumulation of early/central memory (Tcm) cells. Exposure to TGFβ suppressed the expression of BLIMP-1, a key orchestrator of effector T-cell differentiation, and led to the upregulation of the memory-associated transcription factor ID3. Accordingly, this was associated with an early memory transcriptional signature in both CD4⁺ and CD8⁺ T-cell subsets. The T cells stimulated in the presence of TGFβ expanded normally, and displayed polyfunctional features and no suppressive activity. The adoptive transfer of ex vivo-stimulated T cells into immunodeficient mice confirmed that TGFβ-conditioned cells had an enhanced capacity to persist and mediate xenogeneic graft-versus-host disease, as predicted by their early T-cell memory phenotype. Chimeric antigen receptor-expressing T cells generated in the presence of exogenous TGFβ were cytotoxic and more effective at controlling tumor growth in immunodeficient animals. This work unveils a new role for TGFβ in memory T-cell differentiation and indicates that TGFβ signaling may be harnessed to program Tcm differentiation in the context of ex vivo T-cell stimulation for adoptive immunotherapy in humans.

Blockade of TGF-β signaling: a potential target for cancer immunotherapy?

Introduction: Malignant tumors often escape surveillance and eventual destruction by the host immune system through a variety of strategies including production of transforming growth factor (TGF)-β. Because of its generally immunosuppressive role, TGF-β has emerged as a promising therapeutic target in cancer immunotherapy. Areas covered: This article looks at specific mechanisms of how TGF-β controls the function of various immune cell subsets in the tumor microenvironment and focusses on T-cells. Various inhibition tools of TGF-β signaling and potential targets of therapeutic intervention are assessed along with the recent progress in combining TGF-β blockade and immune-mediated therapies. To round off the article, a summary of results from clinical trials is provided in which TGF-β blockade has shown therapeutic benefit for patients. Expert opinion: Data from preclinical models have shown that blocking TGF-β signaling can overcome resistance mechanisms and in combination with immune-checkpoint therapies, can yield additive or synergistic anti-tumor responses. The future of immunooncology will therefore be based on combination trials. Since response rates may critically depend on both cancer type and stage, selection of only those patients who can benefit from combinatorial immunotherapy regimens is of utmost importance.

Transforming Growth Factor-β Signaling in Immunity and Cancer

Transforming growth factor (TGF)-β is a crucial enforcer of immune homeostasis and tolerance, inhibiting the expansion and function of many components of the immune system. Perturbations in TGF-β signaling underlie inflammatory diseases and promote tumor emergence. TGF-β is also central to immune suppression within the tumor microenvironment, and recent studies have revealed roles in tumor immune evasion and poor responses to cancer immunotherapy. Here, we present an overview of the complex biology of the TGF-β family and its context-dependent nature. Then, focusing on cancer, we discuss the roles of TGF-β signaling in distinct immune cell types and how this knowledge is being leveraged to unleash the immune system against the tumor.