Autocrine release of interleukin-9 promotes Jak3-dependent survival of ALK+ anaplastic large-cell lymphoma cells

Functional diversity and regulation of IL-9-producing T cells in cancer immunotherapy

IL-9-producing T cells (T9) regulate immunological responses that affect various cellular biological processes, though their precise function remains fully understood. Previous studies have linked T9 cells to conditions such as allergic disorders, parasitic infection clearance, and various types of cancers. While the functional heterogeneity of IL-9 and T9 cells in cancer development has been documented, these cells present promising therapeutic opportunities for treating solid tumors. This review highlights the roles of IL-9 and T9 cells in cancer progression and treatment responses, focusing on potential discrepancies in IL-9/IL-9R signaling between murine tumors and cancer patients. Additionally, we discuss the regulation of tumor-specific Th9/Tc9 cell differentiation, the therapeutic potential of these cells, and current strategies to enhance their anti-tumor activities.

A reappraisal of IL-9 in inflammation and cancer

While much is known about the functional effects of type 2 cytokines interleukin (IL)-4, IL-5 and IL-13 in homeostasis and disease, we still poorly understand the functions of IL-9. Chronic inflammation seen in allergic diseases, autoimmunity and cancer is however frequently accompanied by overproduction of this elusive type 2 cytokine. Initially identified as a T cell and mast cell growth factor, and later as the hallmark cytokine defining TH9 cells, we now know that IL-9 is produced by multiple innate and adaptive immune cells. Recent evidence suggests that IL-9 controls discrete aspects of the allergic cascade, cellular responses of immune and stromal cells, cancer progression, tolerance and immune escape. Despite functioning as a pleiotropic cytokine in mucosal environments, like the lungs, the direct and indirect cellular targets of IL-9 are still not well characterized. Here, we discuss IL-9's cellular senders and receivers, focusing on asthma and cancer. Moreover, we review current research directions and the outlook of targeted therapy centered around the biology of IL-9.

The emerging role of T helper 9 (Th9) cells in immunopathophysiology: A comprehensive review of their effects and responsiveness in various disease states

Th9 cells, a subset of T-helper cells producing interleukin-9 (IL-9), play a vital role in the adaptive immune response and have diverse effects in different diseases. Regulated by transcription factors like PU.1 and IRF4, and cytokines such as IL-4 and TGF-β, Th9 cells drive tissue inflammation. This review focuses on their emerging role in immunopathophysiology. Th9 cells exhibit immune-mediated cancer cell destruction, showing promise in glioma and cervical cancer treatment. However, their role in breast and lung cancer is intricate, requiring a deeper understanding of pro- and anti-tumor aspects. Th9 cells, along with IL-9, foster T cell and immune cell proliferation, contributing to autoimmune disorders. They are implicated in psoriasis, atopic dermatitis, and infections. In allergic reactions and asthma, Th9 cells fuel pro-inflammatory responses. Targeting Foxo1 may regulate innate and adaptive immune responses, alleviating disease symptoms. This comprehensive review outlines Th9 cells' evolving immunopathophysiological role, emphasizing the necessity for further research to grasp their effects and potential therapeutic applications across diseases.

Intratumoral Delivery of Interleukin 9 via Oncolytic Vaccinia Virus Elicits Potent Antitumor Effects in Tumor Models

The success of cancer immunotherapy is largely associated with immunologically hot tumors. Approaches that promote the infiltration of immune cells into tumor beds are urgently needed to transform cold tumors into hot tumors. Oncolytic viruses can transform the tumor microenvironment (TME), resulting in immunologically hot tumors. Cytokines are good candidates for arming oncolytic viruses to enhance their function in this transformation. Here, we used the oncolytic vaccinia virus (oVV) to deliver interleukin-9 (IL-9) into the tumor bed and explored its antitumor effects in colon and lung tumor models. Our data show that IL-9 prolongs viral persistence, which is probably mediated by the up-regulation of IL-10. The vvDD-IL-9 treatment elevated the expression of Th1 chemokines and antitumor factors such as IFN-γ, granzyme B, and perforin. IL-9 expression increased the percentages of CD4+ and CD8+ T cells in the TME and decreased the percentage of oVV-induced immune suppressive myeloid-derived suppressor cells (MDSC), leading to potent antitumor effects compared with parental virus treatment. The vvDD-IL-9 treatment also increased the percentage of regulatory T cells (Tregs) in the TME and elevated the expression of immune checkpoint molecules such as PD-1, PD-L1, and CTLA-4, but not GITR. The combination therapy of vvDD-IL-9 and the anti-CTLA-4 antibody, but not the anti-GITR antibody, induced systemic tumor-specific antitumor immunity and significantly extended the overall survival of mice, indicating a potential translation of the IL-9-expressing oncolytic virus into a clinical trial to enhance the antitumor effects elicited by an immune checkpoint blockade for cancer immunotherapy.

The crosstalk of CD8+ T cells and ferroptosis in cancer

Ferroptosis is an iron-dependent, novel form of programmed cell death characterized by lipid peroxidation and glutathione depletion and is widespread in a variety of diseases. CD8+ T cells are the most important effector cells of cytotoxic T cells, capable of specifically recognizing and killing cancer cells. Traditionally, CD8+ T cells are thought to induce cancer cell death mainly through perforin and granzyme, and Fas-L/Fas binding. In recent years, CD8+ T cell-derived IFN-γ was found to promote cancer cell ferroptosis by multiple mechanisms, including upregulation of IRF1 and IRF8, and downregulation of the system XC-, while cancer cells ferroptosis was shown to enhance the anti-tumor effects of CD8+ T cell by heating the tumor immune microenvironment through the exposure and release of tumor-associated specific antigens, which results in a positive feedback pathway. Unfortunately, the intra-tumoral CD8+ T cells are more sensitive to ferroptosis than cancer cells, which limits the application of ferroptosis inducers in cancer. In addition, CD8+ T cells are susceptible to being regulated by other immune cell ferroptosis in the TME, such as tumor-associated macrophages, dendritic cells, Treg, and bone marrow-derived immunosuppressive cells. Together, these factors build a complex network of CD8+ T cells and ferroptosis in cancer. Therefore, we aim to integrate relevant studies to reveal the potential mechanisms of crosstalk between CD8+ T cells and ferroptosis, and to summarize preclinical models in cancer therapy to find new therapeutic strategies in this review.

5-Fluorouracil-Loaded PLGA Declined Expression of Pro-Inflammatory Genes IL-9, IL-17A, IL-23 and IFN- y; in the HT-29 Colon Cancer Cell Line

Background

Pro-inflammatory cytokines play critical roles in cancer pathobiology and have been considered potential targets for cancer management and therapy. Understanding the impact of cancer therapeutics such as 5-fluorouracil (5-FU) on their expression might shed light on development of novel combinational therapies. This study aimed to encapsulate 5-FU into PLGA and evaluate their effects on the expression of pro-inflammatory genes IL-9, IL-17-A, IL-23, and IFN-y; in the HT-29 cells.

Methods

PLGA-5-FU NPs were constructed and characterized by Dynamic Light Scattering (DLS) and Atomic Force Microscopy (AFM). The cytotoxicity was evaluated by MTT test and, the IC50 was identified. HT-29 cells were treated with different concentrations of the PLGA-5-FU NPs for 48 hours and, gene expression levels were analyzed by qRT-PCR.

Results

DLS and AFM analysis revealed that the prepared PLGA-5-FU NPs were negatively charged spherical-shaped particles with a mean size of 215.9 ± 43.3 nm. PLGA-5-FU NPs impacted the viability of HT-29 cells in a dose- and time-dependent manner. The qRT-PCR results revealed a dose-dependent decrease in the expression of IL-9, IL-17A, IL-23 and IFN-y; genes, and their expressions were significantly different in both 10 and 20 µg/mL treated groups compared to the control. However, although the treatment of HT-29 cells with 20 µg/mL free 5-FU resulted in decreased expression of the studied genes, the differences were not statistically significant compared to the control group.

Conclusion

PLGA-5-FU NPs significantly suppressed expression of the IL-9, IL-17A, IL-23 and IFN-y; genes, and the encapsulation of 5-FU into PLGA improved considerably impact of the 5-FU on the HT-29 cells.

The World according to IL-9

Among the cytokines regulating immune cells, IL-9 has gained considerable attention for its ability to act on multiple cell types as a regulator of beneficial and pathologic immune responses. Yet, it is still not clearly defined how IL-9 impacts immune responses. IL-9 demonstrates a remarkable degree of tissue-specific functionality and has cellular sources that vary by tissue site and the context of the inflammatory milieu. Here, we provide perspective to summarize the biological activities of IL-9 and highlight cell type-specific roles in the immune pathogenesis of diseases. This perspective will be important in defining the diseases where targeting IL-9 as a therapeutic strategy would be beneficial and where it has the potential to complicate clinical outcomes.

The Dichotomy of Interleukin-9 Function in the Tumor Microenvironment

Interleukin 9 (IL-9) is a cytokine with potent proinflammatory properties that plays a central role in pathologies such as allergic asthma, immunity to parasitic infection, and autoimmunity. More recently, IL-9 has garnered considerable attention in tumor immunity. Historically, IL-9 has been associated with a protumor function in hematological malignancies and an antitumor function in solid malignancies. However, recent discoveries of the dynamic role of IL-9 in cancer progression suggest that IL-9 can act as both a pro- or antitumor factor in various hematological and solid malignancies. This review summarizes IL-9-dependent control of tumor growth, regulation, and therapeutic applicability of IL-9 blockade and IL-9-producing cells in cancer.

Role and Potential of Different T Helper Cell Subsets in Adoptive Cell Therapy

Historically, CD8⁺ T cells have been considered the most relevant effector cells involved in the immune response against tumors and have therefore been the focus of most cancer immunotherapy approaches. However, CD4⁺ T cells and their secreted factors also play a crucial role in the tumor microenvironment and can orchestrate both pro- and antitumoral immune responses. Depending on the cytokine milieu to which they are exposed, CD4⁺ T cells can differentiate into several phenotypically different subsets with very divergent effects on tumor progression. In this review, we provide an overview of the current knowledge about the role of the different T helper subsets in the immune system, with special emphasis on their implication in antitumoral immune responses. Furthermore, we also summarize therapeutic applications of each subset and its associated cytokines in the adoptive cell therapy of cancer.

Amphiregulin/epidermal growth factor receptor/hypoxia-inducible factor-1α pathway regulates T helper 9 and T cytotoxic 9 cell response in adult patients with infectious mononucleosis

Amphiregulin (AREG)/epidermal growth factor receptor (EGFR) signaling induces hypoxia-inducible factor-1α (HIF-1α), leading to promotion of T helper 9 (Th9) differentiation and anti-tumor functions. However, the role of the AREG/EGFR/HIF-1α pathway in regulating interleukin-9 (IL-9) production by T cells in adult patients with infectious mononucleosis (IM) has not been fully elucidated. Fifty IM patients and 20 controls were enrolled. The percentages of Th9 and T cytotoxic 9 (Tc9) cells, the mRNA relative expressions of the transcription factors of IL-9-secreting T cells, purine-rich nucleic acid binding protein 1 (PU.1) and forkhead box protein O1 (FOXO1), and the levels of IL-9, AREG, EGFR, and HIF-1α were measured. Peripheral blood mononuclear cells from IM patients were stimulated with EGFR inhibitor or exogenous AREG in the presence or absence of anti-HIF-1α. Regulation of the AREG/EGFR/HIF-1α pathway to IL-9 production by T cells was assessed. The percentages of Th9 and Tc9 cells, plasma IL-9 levels, and PU.1 and FOXO1 mRNA expressions were elevated in IM patients. Plasma levels of AREG and HIF-1α were also increased in IM patients. AREG levels correlated positively with the percentages of Th9 and Tc9 cells in IM patients. Inhibition of EGFR suppressed IL-9-producing T cell differentiation and HIF-1α production. Exogenous AREG stimulation not only induced EGFR and HIF-1α expression but also promoted IL-9-secreting T cell differentiation. Neutralization of HIF-1α abrogated AREG/EGFR-induced Th9 and Tc9 differentiation in IM patients. The current data suggested that the AREG/EGFR/HIF-1α pathway contributed to the elevation of Th9 and Tc9 differentiation in IM patients.

Anaplastic lymphoma kinase-special immunity and immunotherapy

Alterations in the anaplastic lymphoma kinase (ALK) gene play a key role in the development of various human tumors, and targeted therapy has transformed the treatment paradigm for these oncogene-driven tumors. However, primary or acquired resistance remains a challenge. ALK gene variants (such as gene rearrangements and mutations) also play a key role in the tumor immune microenvironment. Immunotherapy targeting the ALK gene has potential clinical applications. Here, we review the results of recent studies on the immunological relevance of ALK-altered tumors, which provides important insights into the development of tumor immunotherapies targeting this large class of tumors.

Dual Effect of Immune Cells within Tumour Microenvironment: Pro- and Anti-Tumour Effects and Their Triggers

Our body is constantly exposed to pathogens or external threats, but with the immune response that our body can develop, we can fight off and defeat possible attacks or infections. Nevertheless, sometimes this threat comes from an internal factor. Situations such as the existence of a tumour also cause our immune system (IS) to be put on alert. Indeed, the link between immunology and cancer is evident these days, with IS being used as one of the important targets for treating cancer. Our IS is able to eliminate those abnormal or damaged cells found in our body, preventing the uncontrolled proliferation of tumour cells that can lead to cancer. However, in several cases, tumour cells can escape from the IS. It has been observed that immune cells, the extracellular matrix, blood vessels, fat cells and various molecules could support tumour growth and development. Thus, the developing tumour receives structural support, irrigation and energy, among other resources, making its survival and progression possible. All these components that accompany and help the tumour to survive and to grow are called the tumour microenvironment (TME). Given the importance of its presence in the tumour development process, this review will focus on one of the components of the TME: immune cells. Immune cells can support anti-tumour immune response protecting us against tumour cells; nevertheless, they can also behave as pro-tumoural cells, thus promoting tumour progression and survival. In this review, the anti-tumour and pro-tumour immunity of several immune cells will be discussed. In addition, the TME influence on this dual effect will be also analysed.

The Roles of IRF-8 in Regulating IL-9-Mediated Immunologic Mechanisms in the Development of DLBCL: A State-of-the-Art Literature Review

Interferon regulatory factor 8 (IRF-8) is a transcription suppressor that functions through associations with other transcription factors, contributing to the growth and differentiation of bone marrow cells and the activation of macrophages. IRF-8 expression profoundly affects pathogenic processes ranging from infections to blood diseases. Interleukin-9 (IL-9) is a multipotent cytokine that acts on a variety of immune cells by binding to the IL-9 receptor (IL-9R) and is involved in a variety of diseases such as cancer, autoimmune diseases, and other pathogen-mediated immune regulatory diseases. Studies have shown that IL-9 levels are significantly increased in the serum of patients with diffuse large B-cell lymphoma (DLBCL), and IL-9 levels are correlated with the DLBCL prognostic index. The activator protein-1 (AP-1) complex is a dimeric transcription factor that plays a critical role in cellular proliferation, apoptosis, angiogenesis, oncogene-induced transformation, and invasion by controlling basic and induced transcription of several genes containing the AP-1 locus. The AP-1 complex is involved in many cancers, including hematological tumors. In this report, we systematically review the precise roles of IL-9, IRF-8, and AP-1 in tumor development, particularly with regard to DLBCL. Finally, the recent progress in IRF-8 and IL-9 research is presented; the possible relationship among IRF-8, IL-9, and AP-1 family members is analyzed; and future research prospects are discussed.

Interleukin (IL)-9 Supports the Tumor-Promoting Environment of Chronic Lymphocytic Leukemia

Simple Summary

Interleukin 9 (IL-9), a soluble factor secreted by immune cells, has been found in several tumor niches where, depending on the specific tumor type, it either promotes or counteracts tumor development. Recently, IL-9 has been implicated in the development of chronic lymphocytic leukemia, although the underlying molecular mechanism remains unknown. Here, we summarize the current knowledge concerning the roles of IL-9 in disease, with a focus on its implication in the pathogenesis of chronic lymphocytic leukemia.

Abstract

Interleukin (IL)-9 is a soluble factor secreted by immune cells into the microenvironment. Originally identified as a mediator of allergic responses, IL-9 has been detected in recent years in several tumor niches. In solid tumors, it mainly promotes anti-tumor immune responses, while in hematologic malignancies, it sustains the growth and survival of neoplastic cells. IL-9 has been recently implicated in the pathogenesis of chronic lymphocytic leukemia; however, the molecular mechanisms underlying its contribution to this complex neoplasia are still unclear. Here, we summarize the current knowledge of IL-9 in the tumor microenvironment, with a focus on its role in the pathogenesis of chronic lymphocytic leukemia.

Cytokines, Genetic Lesions and Signaling Pathways in Anaplastic Large Cell Lymphomas

ALCL is a tumor of activated T cells and possibly innate lymphoid cells with several subtypes according to clinical presentation and genetic lesions. On one hand, the expression of transcription factors and cytokine receptors triggers signaling pathways. On the other hand, ALCL tumor cells also produce many proteins including chemokines, cytokines and growth factors that affect patient symptoms. Examples are accumulation of granulocytes stimulated by IL-8, IL-17, IL-9 and IL-13; epidermal hyperplasia and psoriasis-like skin lesions due to IL-22; and fever and weight loss in response to IL-6 and IFN-γ. In this review, we focus on the biology of the main ALCL subtypes as the identification of signaling pathways and ALCL-derived cytokines offers opportunities for targeted therapies.

IL-10, IL-13, Eotaxin and IL-10/IL-6 ratio distinguish breast implant-associated anaplastic large-cell lymphoma from all types of benign late seromas

Breast implant-associated anaplastic large-cell lymphoma (BI-ALCL) is an uncommon peripheral T cell lymphoma usually presenting as a delayed peri-implant effusion. Chronic inflammation elicited by the implant has been implicated in its pathogenesis. Infection or implant rupture may also be responsible for late seromas. Cytomorphological examination coupled with CD30 immunostaining and eventual T-cell clonality assessment are essential for BI-ALCL diagnosis. However, some benign effusions may also contain an oligo/monoclonal expansion of CD30 + cells that can make the diagnosis challenging. Since cytokines are key mediators of inflammation, we applied a multiplexed immuno-based assay to BI-ALCL seromas and to different types of reactive seromas to look for a potential diagnostic BI-ALCL-associated cytokine profile. We found that BI-ALCL is characterized by a Th2-type cytokine milieu associated with significant high levels of IL-10, IL-13 and Eotaxin which discriminate BI-ALCL from all types of reactive seroma. Moreover, we found a cutoff of IL10/IL-6 ratio of 0.104 is associated with specificity of 100% and sensitivity of 83% in recognizing BI-ALCL effusions. This study identifies promising biomarkers for initial screening of late seromas that can facilitate early diagnosis of BI-ALCL.

IL-9-producing T cells: potential players in allergy and cancer

IL-9-producing CD4⁺ T cells have been considered to represent a distinct T helper cell (T_H cell) subset owing to their unique developmental programme in vitro, their expression of distinct transcription factors (including PU.1) and their copious production of IL-9. It remains debatable whether these cells represent a truly unique T_H cell subset in vivo, but they are closely related to the T helper 2 (T_H2) cells that are detected in allergic diseases. In recent years, increasing evidence has also indicated that IL-9-producing T cells may have potent abilities in eradicating advanced tumours, particularly melanomas. Here, we review the latest literature on the development of IL-9-producing T cells and their functions in disease settings, with a particular focus on allergy and cancer. We also discuss recent ideas concerning the therapeutic targeting of these cells in patients with chronic allergic diseases and their potential use in cancer immunotherapy.

Th9 Cell Differentiation and Its Dual Effects in Tumor Development

With the improved understanding of the molecular pathogenesis and characteristics of cancers, the critical role of the immune system in preventing tumor development has been widely accepted. The understanding of the relationship between the immune system and cancer progression is constantly evolving, from the cancer immunosurveillance hypothesis to immunoediting theory and the delicate balance in the tumor microenvironment. Currently, immunotherapy is regarded as a promising strategy against cancers. Although adoptive cell therapy (ACT) has shown some exciting results regarding the rejection of tumors, the effect is not always satisfactory. Cellular therapy with CD4⁺ T cells remains to be further explored since the current ACT is mainly focused on CD8⁺ cytotoxic T lymphocytes (CTLs). Recently, Th9 cells, a subgroup of CD4⁺ T helper cells characterized by the secretion of IL-9 and IL-10, have been reported to be effective in the elimination of solid tumors and to exhibit superior antitumor properties to Th1 and Th17 cells. In this review, we summarize the most recent advances in the understanding of Th9 cell differentiation and the dual role, both anti-tumor and pro-tumor effects, of Th9 cells in tumor progression.

Comparative Analysis of Cytokines of Tumor Cell Lines, Malignant and Benign Effusions Around Breast Implants

BACKGROUND

More than 700 women have developed an anaplastic large T cell lymphoma (ALCL) surrounding textured surface breast implants, termed breast implant-associated ALCL (BIA-ALCL). Most patients with BIA-ALCL present with an accumulation of fluid (delayed seroma) around the implant. However, benign seromas without malignant cells complicating scar contracture, implant rupture, trauma, infection, and other causes are more common. For proper patient management and to avoid unnecessary surgery, a simple diagnostic test to identify malignant seromas is desirable.

OBJECTIVES

The aim of this study was to develop an ancillary test for the diagnosis of malignant seromas and to gain insight into the nature of the malignant cells and their microenvironment.

METHODS

We employed an immunologic assay on only 50 µL of aspirated seroma fluid. The assay measures 13 cytokines simultaneously by flow cytometry. To establish a baseline for clinical studies we measured cytokines secreted by BIA-ALCL and cutaneous ALCL lines.

RESULTS

Our study of cell line culture supernatants, and 8 malignant compared with 9 benign seromas indicates that interleukin 9 (IL-9), IL-10, IL-13, IL-22, and/or interferon γ concentrations >1000 pg/mL distinguish malignant seromas from benign seromas. IL-6, known to be a driver of malignant cells, is also elevated in benign seromas and does not distinguish them from malignant seromas.

CONCLUSIONS

The cytokine assay introduced in this study can be used together with levels of soluble CD30 to identify malignant seromas. Validation of these findings in a larger prospective patient cohort is warranted. The unique pattern of cytokine expression in malignant effusions surrounding breast implants gives further insight into the pathogenesis and cells of origin of BIA-ALCL.

Level of Evidence: 5.

IL-9 and IL-9-producing cells in tumor immunity

Abstract

Interleukin (IL)-9 belongs to the IL-2Rγc chain family and is a multifunctional cytokine that can regulate the function of many kinds of cells. It was originally identified as a growth factor of T cells and mast cells. In previous studies, IL-9 was mainly involved in the development of allergic diseases, autoimmune diseases and parasite infections. Recently, IL-9, as a double-edged sword in the development of cancers, has attracted extensive attention. Since T-helper 9 (Th9) cell-derived IL-9 was verified to play a powerful antitumor role in solid tumors, an increasing number of researchers have started to pay attention to the role of IL-9-skewed CD8⁺ T (Tc9) cells, mast cells and Vδ2 T cell-derived IL-9 in tumor immunity. Here, we review recent studies on IL-9 and several kinds of IL-9-producing cells in tumor immunity to provide useful insight into tumorigenesis and treatment.

Clinico-Biological Implications of Modified Levels of Cytokines in Chronic Lymphocytic Leukemia: A Possible Therapeutic Role

B-cell chronic lymphocytic leukemia (B-CLL) is the main cause of mortality among hematologic diseases in Western nations. B-CLL is correlated with an intense alteration of the immune system. The altered functions of innate immune elements and adaptive immune factors are interconnected in B-CLL and are decisive for its onset, evolution, and therapeutic response. Modifications in the cytokine balance could support the growth of the leukemic clone via a modulation of cellular proliferation and apoptosis, as some cytokines have been reported to be able to affect the life of B-CLL cells in vivo. In this review, we will examine the role played by cytokines in the cellular dynamics of B-CLL patients, interpret the contradictions sometimes present in the literature regarding their action, and evaluate the possibility of manipulating their production in order to intervene in the natural history of the disease.

Targeting the IL-9 pathway in cancer immunotherapy

Interleukin (IL)-9 is a pleiotropic cytokine, which can function as a positive or negative regulator of immune responses on multiple types of cells. The role of IL-9 was originally known in allergic disease and parasite infections. Interestingly, recent studies demonstrate its presence in the tumor tissues of mice and humans, and the association between IL-9 and tumor progression has been revisited following the discovery of T helper (Th) 9 cells. Tumor-specific Th9 cells are considered to be the main subset of CD4⁺ T cells that produce high level of IL-9 and exhibit an IL-9-dependent robust anti-cancer function in solid tumors. IL-9 exerts an unprecedented anti-tumor immunity not only by inducing innate and adaptive immune responses but also directly promoting apoptosis of tumor cells. The objective of this review is to summarize the latest advances regarding the anti-tumor mechanisms of IL-9 and Th9 cells.

Interleukin-9 promotes tumorigenesis through augmenting angiogenesis in non-small cell lung cancer

IL-9 is a proinflammatory cytokine that plays a critical role in autoimmunity and inflammatory diseases. However, its role in tumorigenesis has not been well studied. In this study, we found that IL-9 expression was significantly increased and associated with poor progression in human non-small cell lung cancer (NSCLC). Ectopic expression of IL-9 in NSCLC cells did not affect cell proliferation and apoptosis in vitro, but markedly promoted tumor growth in vivo. Immune-profile analysis showed no significant changes in the frequencies of infiltrated immune cells in the tumor site, neither in nude mice nor in immune-competent mice. However, we found that VEGF and microvessel density (MVD) were significantly increased in xenografts. IL-9 could promote cell growth and tube formation of HUVEC cells in vitro. In addition, correlation analysis implied a significant positive relationship between the density of IL-9 and VEGF, as well as MVD in human NSCLC tissues. Finally, we found that IL-9 stimulated tumor angiogenesis via STAT3 signaling. Together, our findings demonstrate a promoting role of IL-9 in lung cancer development, probably through promoting tumor angiogenesis. IL-9 thus may represent a new prognostic marker and therapeutic target for NSCLC.

The Role of Interleukin-9 in Cancer

Interluekin-9 (IL-9) is produced predominantly by helper T cells such as Th2 and Th9 cells. It normally functions through the activation of a JAK/STAT pathway and plays a critical role in immunity and the pathogenesis of cancer. In cancer, it yields different responses depending on the cancer cell line involved. This review is a summary of what is known about the involvement of IL-9 in various cancer cell lines as well as its role in immunity with a focus on allergic responses.

What Cytokines Can Tell Us About the Pathogenesis of Breast Implant-Associated Anaplastic Large Cell Lymphoma (BIA-ALCL)

Cytokines, their receptors, and downstream signaling partners, especially JAK1/2 and STAT3, are key biomarkers in lymphoproliferative disorders including systemic anaplastic large cell lymphoma (ALCL). Here we review their role in breast implant-associated anaplastic large cell lymphoma (BIA-ALCL). Early results suggest that, in addition to CD30, IL-9, IL-10, and IL-13 can distinguish malignant from benign seromas. IL-6 is increased in both benign and malignant seromas. IFNγ may identify a subset of BIA-ALCL with a different clinical course. Immunohistochemical detection of nuclear transcription factors-which regulate cytokine signaling-and phosphorylated janus kinases/signal transducers and activators of transcription can inform the identification and malignant potential of CD30+ cells. The innate immune response is the first line of defense against microbes suspected to initiate BIA-ALCL. Innate lymphoid cells are grouped according to the cytokines they produce and could potentially be identified as precursors to BIA-ALCL. Cytokines modulate the tumor microenvironment and hence the pathology of BIA-ALCL such as the influx of eosinophils and capsular fibrosis mediated by IL-13. The plasticity of T cells and innate immune cells theoretically can enable therapeutic manipulations toward a less aggressive phenotype. Cytokine receptors targeted in clinical trials of inflammatory and autoimmune disorders could afford opportunities for immunotherapy of BIA-ALCL.

Novel insights into the pathogenesis of T-cell lymphomas

T-cell lymphomas are a heterogeneous group of rare malignancies with overlapping clinical, immunologic, and histologic features. Recent advances in our understanding of T-cell differentiation based on gene expression profiling, next-generation sequencing, and transgenic mouse modeling studies have better elucidated the pathogenetic mechanisms underlying the diverse biology of T-cell lymphomas. These studies show that although genetic alterations in epigenetic modifiers are implicated in all subtypes of T-cell lymphomas, specific subtypes demonstrate enrichment for particular recurrent alterations targeting specific genes. In this regard, RHOA and TET2 alterations are prevalent in nodal T-cell lymphomas, particularly angioimmunoblastic T-cell lymphomas, peripheral T-cell lymphomas (PTCLs) not otherwise specified, and nodal PTCLs with T-follicular helper phenotype. JAK-STAT signaling pathways are mutationally activated in many extranodal T-cell lymphomas, such as natural killer/T-cell and hepatosplenic T-cell lymphomas. The functional significance of many of these genetic alterations is becoming better understood. Altogether these advances will continue to refine diagnostic criteria, improve prognostication, and identify novel therapeutic targets, resulting in improved outcomes for patient with T-cell lymphomas.

Blood cytokine concentrations in pediatric patients with anaplastic lymphoma kinase-positive anaplastic large cell lymphoma

Patients with anaplastic lymphoma kinase-positive anaplastic large cell lymphoma often present with B-symptoms or hemophagocytosis and generate an anti-tumor immune response. Specific serum cytokine levels or profiles may reflect the tumor burden, non-specific immune stimulation by the tumor or differences in the strength of the patients’ anti-lymphoma immunity. We systematically correlated pretreatment concentrations of 25 cytokines with clinical and biological characteristics in a well-characterized cohort of 119 uniformly treated pediatric patients with anaplastic large cell lymphoma. Fifteen patients with anaplastic large cell lymphoma in remission and 11 patients with low-stage B-cell lymphoma served as controls. Concentrations of interleukin-9, interleukin-10, interleukin-17a, hepatocyte growth factor, soluble interleukin-2 receptor, and soluble CD30 were significantly higher in initial sera of patients than in the sera of subjects from both control groups, indicating an anaplastic large cell lymphoma-type cytokine signature. The levels of interleukin-6, interferon-γ, interferon γ-induced protein, and soluble interleukin-2 receptor correlated with the stage, initial general condition, minimal disseminated disease, anaplastic lymphoma kinase-antibody titers, and the risk of relapse among patients with anaplastic lymphoma kinase-positive anaplastic large cell lymphoma. Only interleukin-6 showed an independent prognostic value in multivariate analyses. Pretreatment cytokine profiles in patients with anaplastic large cell lymphoma reflect a tumor signature as well as tumor burden and also differences in the strength of the patients’ immune response.

Dual Face of Vγ9Vδ2-T Cells in Tumor Immunology: Anti- versus Pro-Tumoral Activities

Vγ9Vδ2-T cells are considered as potent effector cells for tumor immunotherapy through directly killing tumor cells and indirectly regulating other innate and adaptive immune cells to establish antitumoral immunity. The antitumoral activity of Vγ9Vδ2-T cells is governed by a complicated set of activating and inhibitory cell receptors. In addition, cytokine milieu in tumor microenvironment can also induce the pro-tumoral activities and functional plasticity of Vγ9Vδ2-T cells. Here, we review the anti- versus pro-tumoral activities of Vγ9Vδ2-T cells and discuss the mechanisms underlying the recognition, activation, differentiation and regulation of Vγ9Vδ2-T cells in tumor immunosurveillance. The comprehensive understanding of the dual face of Vγ9Vδ2-T cells in tumor immunology may improve the therapeutic efficacy and clinical outcomes of Vγ9Vδ2-T cell-based tumor immunotherapy.

Evaluation of Interleukin-9 Expression as a Potential Therapeutic Target in Chronic Lymphocytic Leukemia in a Cohort of Egyptian Patients

Chronic lymphocytic leukemia (CLL) is a common lymphoid malignancy that has a highly variable clinical course. Genomic features as zeta-chain-associated protein kinase 70 (ZAP70) expression and CD38 expression provide further differentiation of disease prognosis. Extensive studies have confirmed the oncogenic activities of IL-9 in lymphoma. The aim of the current study was to investigate the contribution of IL-9 expression to the pathogenesis of CLL and its correlation to other prognostic parameters. This study was conducted on 80 patients at diagnosis with CLL and 80 healthy controls. Using real time polymerase chain reaction and enzyme linked immunosorbant assay, IL-9 mRNA expression and its serum level were compared between patients and controls. They were both correlated with other prognostic factors.

RESULTS

There was an overexpression of IL-9 in CLL patients that correlated with modified Rai staging, ZAP70, CD38 and all hallmarks of an active and aggressive disease. The correlation between IL-9 upregulation and patient characteristics provided direct clinical evidence for its contribution to the pathogenesis of CLL. In conclusion, significantly higher expression of IL-9 measured at both the mRNA and the protein levels in patients with CLL that correlates with more complex course of the disease and worse prognosis may allow one to speculate its importance in the pathogenesis of the disease and its possible impact on prognosis.

Sensitivity Analysis of the NPM-ALK Signalling Network Reveals Important Pathways for Anaplastic Large Cell Lymphoma Combination Therapy

A large subset of anaplastic large cell lymphoma (ALCL) patients harbour a somatic aberration in which anaplastic lymphoma kinase (ALK) is fused to nucleophosmin (NPM) resulting in a constitutively active signalling fusion protein, NPM-ALK. We computationally simulated the signalling network which mediates pathological cell survival and proliferation through NPM-ALK to identify therapeutically targetable nodes through which it may be possible to regain control of the tumourigenic process. The simulations reveal the predominant role of the VAV1-CDC42 (cell division control protein 42) pathway in NPM-ALK-driven cellular proliferation and of the Ras / mitogen-activated ERK kinase (MEK) / extracellular signal-regulated kinase (ERK) cascade in controlling cell survival. Our results also highlight the importance of a group of interleukins together with the Janus kinase 3 (JAK3) / signal transducer and activator of transcription 3 (STAT3) signalling in the development of NPM-ALK derived ALCL. Depending on the activity of JAK3 and STAT3, the system may also be sensitive to activation of protein tyrosine phosphatase-1 (SHP1), which has an inhibitory effect on cell survival and proliferation. The identification of signalling pathways active in tumourigenic processes is of fundamental importance for effective therapies. The prediction of alternative pathways that circumvent classical therapeutic targets opens the way to preventive approaches for countering the emergence of cancer resistance.

SUMOylation Confers Posttranslational Stability on NPM-ALK Oncogenic Protein

Nucleophosmin-anaplastic lymphoma kinase–expressing (NPM-ALK⁺) T-cell lymphoma is an aggressive form of cancer that commonly affects children and adolescents. The expression of NPM-ALK chimeric oncogene results from the chromosomal translocation t(2;5)(p23;q35) that causes the fusion of the ALK and NPM genes. This translocation generates the NPM-ALK protein tyrosine kinase that forms the constitutively activated NPM-ALK/NPM-ALK homodimers. In addition, NPM-ALK is structurally associated with wild-type NPM to form NPM/NPM-ALK heterodimers, which can translocate to the nucleus. The mechanisms that sustain the stability of NPM-ALK are not fully understood. SUMOylation is a posttranslational modification that is characterized by the reversible conjugation of small ubiquitin-like modifiers (SUMOs) with target proteins. SUMO competes with ubiquitin for substrate binding and therefore, SUMOylation is believed to protect target proteins from proteasomal degradation. Moreover, SUMOylation contributes to the subcellular distribution of target proteins. Herein, we found that the SUMOylation pathway is deregulated in NPM-ALK⁺ T-cell lymphoma cell lines and primary lymphoma tumors from patients. We also identified Lys²⁴ and Lys³² within the NPM domain as the sites where NPM-ALK conjugates with SUMO-1 and SUMO-3. Importantly, antagonizing SUMOylation by the SENP1 protease decreased the accumulation of NPM-ALK and suppressed lymphoma cell viability, proliferation, and anchorage-independent colony formation. One possible mechanism for the SENP1-mediated decrease in NPM-ALK levels was the increase in NPM-ALK association with ubiquitin, which facilitates its degradation. Our findings propose a model in which aberrancies in SUMOylation contribute to the pathogenesis of NPM-ALK⁺ T-cell lymphoma. Unraveling such pathogenic mechanisms may lead to devising novel strategies to eliminate this aggressive neoplasm.

Interleukin-9 promotes cell survival and drug resistance in diffuse large B-cell lymphoma

Background

Interleukin-9 (IL-9) was discovered as a helper T cell growth factor. It has long been recognized as an important regulator in allergic inflammation. Recent years it was discovered to induce cell growth and differentiation of multiple transformed cells. However, its oncogenic activities in B-cell lymphomas have not been reported in detail.

Methods

Serum levels of IL-9 in DLBCL patients were quantified by ELISA, and its clinical significance was analysed. The expression of IL-9 receptor (IL-9R) was investigated in lymphoma cell lines by RT-PCR and western blot, respectively. In DLBCL cell lines LY1 and LY8, IL-9R genes were knocked down by RNA interference and stable transfected cells were selected with puromycin. Normal and final siIL-9R (and siControl) LY1 and LY8 cells were treated with IL-9 alone and in synergy with chemotherapeutic drugs. Cell proliferation and apoptosis were assessed by Brdu incorporation and flow cytometric analysis. The mRNA of apoptosis regulation genes were measured with real-time PCR.

Results

Elevated serum levels of IL-9 were detected in DLBCL patients (24/30) compared to healthy controls (0/15). Positive expression of IL-9 (defined as a serum level ≥1 pg/ml) was correlated with lower serum albumin levels and high international prognostic index (IPI) scores. IL-9R was expressed in both mRNA and protein levels in the five lymphoma cell lines, including LY1, LY8, MINO, SP53 and Jurkat. In vitro studies showed that IL-9 directly induced proliferation and inhibited apoptosis in LY1 and LY8 cells. It protects LY1 and LY8 cells from prednisolone induced apoptosis, and promotes their proliferation that were inhibited by rituximab, vincristine and prednisolone. Its molecular mechanism may be concerned with upregulating expression of p21CIP1 gene. Knock-down of IL-9R gene could reverse the effects of IL-9 on LY1 and LY8 cells.

Conclusions

IL-9 is associated with clinical features of DLBCL patients. It promotes survival of DLBCL cells and reduces the sensitivities of tumor cells to chemotherapeutic drugs via upregulation of p21CIP1 genes.

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-016-0374-3) contains supplementary material, which is available to authorized users.

New insights of common gamma chain in hematological malignancies

The common gamma chain (γc) receptor family of cytokines including interleukin-2 (IL-2), IL-4, IL-7, IL-9, IL-15, and IL-21 has the common feature of sharing γc signaling subunit of their receptors. The γc cytokines have unique biological effects that regulate differentiation, survival and activation of multiple lymphocyte lineages and control proliferation of malignant cell by influencing tumor environment. It has been also described that different types of lymphoid leukemia and lymphoma exhibit expression of divergent γc cytokines and their receptors, as they may promote malignant transformation of lymphoid cells or on the contrary lead to tumor regression by inducing cell-cycle arrest. Therefore, cytokine-based or cytokine-directed blockade in cancer immunotherapy has currently revolutionized the development of cancer treatment. In this review, we will discuss about the role of γc cytokines and their signaling pathways in hematological malignancies and also propose a novel alternative approach that regulates γc cytokine responsiveness by γc in hematological malignancies.

Association between low expression levels of interleukin-9 and colon cancer progression

Although interleukin (IL)-9 has been extensively studied in inflammation and autoimmune diseases, the expression level of IL-9 in colon cancer and its clinical significance are less well established. In total, 15 healthy donors (HDs) and 60 patients who had been diagnosed with colon cancer that had undergone a surgical resection were enrolled in the study. The plasma levels of IL-9 in the HDs and cancer patients were detected by the liquid chip technique, while the expression levels of IL-9 in the colon cancer tissues and normal tissues were analyzed using immunohistochemistry (IHC) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Finally, the difference in the expression levels of IL-9 between the patients classified as tumor-node-metastasis stage I-II and stage III-IV was compared. The results demonstrated that the plasma levels of IL-9 in the patients with colon cancer were significantly lower when compared with the HDs (1.29 vs. 2.53 pg/ml, P<0.05). Furthermore, according to the IHC and RT-qPCR results, low expression levels of IL-9 were observed in the colon cancer tissues when compared with the normal tissues (P<0.05). With regard to the plasma and tumor tissue samples, patients diagnosed with stage III-IV colon cancer expressed lower levels of IL-9 compared with the stage I-II patients (P<0.05). In conclusion, low expression levels of IL-9 were observed in the tissue and plasma samples collected from the colon cancer patients, and the decreased expression of IL-9 was shown to correlate with colon cancer progression.

Neutralization of interleukin-9 ameliorates symptoms of experimental autoimmune myasthenia gravis in rats by decreasing effector T cells and altering humoral responses

Interleukin-9 (IL-9) was initially thought to be a type 2 T helper (Th2)-associated cytokine involved in the regulation of autoimmune responses by affecting multiple cell types. However, it was recently shown that IL-9-producing CD4+ T cells represent a discrete subset of Th cells, designated Th9 cells. Although Th9 cells have been shown to be important in many diseases, their roles in myasthenia gravis (MG) are unclear. The aim of this study was to determine whether IL-9 and Th9 cells promote the progression of experimental autoimmune myasthenia gravis (EAMG). The results showed that the percentage of Th9 cells changed during the progression of EAMG, accompanied by an up-regulation of IL-9. Blocking IL-9 activity with antibodies against IL-9 inhibited EAMG-associated pathology in rats and reduced serum anti-acetylcholine receptor IgG levels. Neutralization of IL-9 altered the Th subset distribution in EAMG, reducing the number of Th1 cells and increasing the number of regulatory T cells. Administration of an anti-IL-9 antibody may represent an effective therapeutic strategy for MG-associated pathologies or other T-cell- or B-cell-mediated autoimmune diseases.

ALK-positive cancer: still a growing entity

 Since the discovery of ALK-positive anaplastic large-cell lymphoma in 1994 many other types of tumors showing ALK expression were disclosed. They form a heterogeneous group, including lung, renal and soft tissue tumors. The biological function of ALK, its role in carcinogenesis and impact exerted on the clinical outcome have been studied by many research groups. New drugs specifically dedicated for ALK inhibition, for example, crizotinib, have been synthesized and have become a viable treatment option for ALK-positive lung adenocarcinoma, and potentially for other ALK-positive cancers. This review summarizes the current state of knowledge concerning ALK-positive neoplasms, focusing on the clinical aspects of the subject.

Overexpression of IL-9 induced by STAT6 activation promotes the pathogenesis of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a common leukemia in adults, but its pathogenesis is still poorly understood. Recently, extensive evidence suggests that the malignant cells of CLL patients secrete a range of cytoprotective cytokines including interleukin-4 (IL-4). IL-4 induced the rapid phosphorylation(p) and activation of the signal transducer and activator of transcription (STAT)-6 transcription factor in CLL cells in vitro. Interleukin-9 (IL-9) is not expressed by Th2 and Th9 cells in the absence of STAT6 expression. To elucidate whether there was a function link between IL-9 and STAT6 in CLL, MEC-1 cells were analyzed using RT-PCR, and western blot. Interestingly, when added with recombinant human IL-4 (rIL-4) in culturing MEC-1 cells, expressions of p-STAT6 and IL-9 in MEC-1 cells increased at a time-dependent manner and their expressions could be inhibited by STAT6 inhibitor. Our data indicated that the upregulation of IL-9 induced by pSTAT6 may be involved in the pathogenesis of CLL.

Serum levels of interleukin-9 correlate with negative prognostic factors in extranodal NK/T-cell lymphoma

Interleukin-9 (IL-9) is more functionally diverse than previously expected, especially with regards to lymphomagenesis. However, the relationship between IL-9 and the clinicopathological features of extranodal NK/T-cell lymphoma is less well established. Patients with this lymphoma in Sun Yat-Sen University Cancer Center between January 2003 and March 2013 were systematically reviewed in an intention-to-treat analysis. Baseline serum IL-9 levels were determined using sandwich enzyme-linked immunosorbent assays. A total of seventy-four patients were enrolled in this study. The mean concentration of serum IL-9 for all patients was 6.48 pg/mL (range: 1.38–51.87 pg/mL). Age, B symptoms and local lymph node involvement were found to be related to high serum IL-9 levels. Patients with low IL-9 levels tended to have higher rates of complete remission. Notably, the median progression-free survival (PFS) and overall survival (OS) were longer in the low IL-9 level group than in the high IL-9 level group (PFS: 68.7 months vs. 28.3 months, P<0.001; OS: 86 months vs. 42.8 months, P = 0.001). Multivariate analysis revealed independent prognostic factors for PFS. Similarly, high IL-9 levels (P = 0.003) and old age (P = 0.007) were independently predictive of shorter OS. Serum IL-9 is closely related to several clinical features, such as age, B symptoms and local lymph node involvement. It can also be a significant independent prognostic factor for extranodal NK/T-cell lymphoma, which suggests a role for IL-9 in the pathogenesis of this disease and offers new insight into potential therapeutic strategies.

ALK-driven tumors and targeted therapy: focus on crizotinib

Receptor tyrosine kinases have emerged as promising therapeutic targets for a diverse set of tumors. Overactivation of the tyrosine kinase anaplastic lymphoma kinase (ALK) has been reported in several types of malignancies such as anaplastic large cell lymphoma, inflammatory myofibroblastic tumor, neuroblastoma, and non-small-cell lung carcinoma. Further characterization of the molecular role of ALK has revealed an oncogenic signaling signature that results in tumor dependence on ALK. ALK-positive tumors display a different behavior than their ALK-negative counterparts; however, the specific role of ALK in some of these tumors remains to be elucidated. Although more studies are required to establish selective targeting of ALK as a definitive therapeutic option, initial trials have shown extraordinary results in the majority of cases.

Role of high expression of IL-9 in prognosis of CLL

Chronic lymphocytic leukemia (CLL) is a common leukemia in adults, but its pathogenesis is still poorly understood. Interleukin-9 (IL-9) is initially described as a growth factor secreted by helper T cells. Recently, the oncogenic activities of IL-9 were reported in some leukemia but not chronic lymphocytic leukemia (CLL). The purpose of the present study is to investigate the expression of IL-9 from patients with CLL and to evaluate its correlation with clinical characteristics. Serum and peripheral blood mononuclear cells (PBMCs) from patients with CLL were analyzed using ELISA, RT-PCR, and western blot. ELISA analysis indicated IL-9 could be detected in 20 of 47 sera from CLL patients while none serum sample from healthy volunteers contained detectable levels of IL-9. There was a higher expression of IL-9 within PBMCs from patients with CLL compared with B cells of healthy blood donors using RT-PCR and western blot. The upregulated IL-9 was correlated to the clinical staging, ZAP-70 expression, β2 microglobulin expression and IgVH status of CLL patients (P<0.05). Our findings suggest that overexpression of IL-9 may contribute to the pathogenesis of CLL and is associated with some adverse prognostic parameters.

The pathobiology of the oncogenic tyrosine kinase NPM-ALK: a brief update

Extensive research has been carried out in the past two decades to study the pathobiology of nucleophosmin-anaplastic lymphoma kinase (NPM-ALK), which is an oncogenic fusion protein found exclusively in a specific type of T-cell lymphoid malignancy, namely ALK-positive anaplastic large cell lymphoma. Results from these studies have provided highly useful insights into the mechanisms by which a constitutively tyrosine kinase, such as NPM-ALK, promotes tumorigenesis. Several previous publications have comprehensively summarized the advances in this field. In this review, we provide readers with a brief update on specific areas of NPM-ALK pathobiology. In the first part, the NPM-ALK/signal transducer and activator of transcription 3 (STAT3) signaling axis is discussed, with an emphasis on the existence of multiple biochemical defects that have been shown to amplify the oncogenic effects of this signaling axis. Specifically, findings regarding JAK3, SHP1 and the stimulatory effects of several cytokines including interleukin (IL)-9, IL-21 and IL-22 are summarized. New concepts stemming from recent observations regarding the functional interactions among the NPM-ALK/STAT3 axis, β catenin and glycogen synthase kinase 3β will be postulated. Lastly, new mechanisms by which the NPM-ALK/STAT3 axis promotes tumorigenesis, such as its modulations of Twist1, hypoxia-induced factor 1α, CD274, will be described. In the second part, we summarize recent data generated by mass spectrometry studies of NPM-ALK, and use MSH2 and heat shock proteins as examples to illustrate the use of mass spectrometry data in stimulating new research in this field. In the third part, the evolving field of microRNA in the context of NPM-ALK biology is discussed.

Overexpression of IL-9 receptor in diffuse large B-cell lymphoma

Interleukin-9 (IL-9) is initially described as a growth factor secreted by helper T cells. It acts on a variety of immune cells via its receptor (IL-9R). Recently, the oncogenic activities of IL-9 and IL-9R were reported in some lymphomas but not diffuse large B-cell lymphoma (DLBCL). The purpose of the present study is to investigate the expression of IL-9R in pathological tissues from patients with DLBCL and to evaluate its correlation with clinical characteristics. Tissue samples from patients with DLBCL and reactive lymphoid hyperplasia were analyzed using RT-PCR, western blot and immunohistochemical staining. There was a higher expression of IL-9R within DLBCL tissues compared with hyperplasic lymph nodes. Immunohistochemical analysis indicated membrane localization of IL-9R in 22 of 36 (61.1%) DLBCL cases. The upregulated IL-9R was correlated to the serum levels of β2 microglobulin and albumin, International Prognostic Index (IPI) score as well as Ki-67 expression within tumor tissues. Our findings suggest that overexpression of IL-9R may contribute to the pathogenesis of DLBCL and is associated with some adverse prognostic parameters.

Increased interleukin‑9 and CD4+IL-9+ T cells in patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease of unknown origin affecting all the organ systems. Apart from genetic and environmental factors, autoantibody and immune complex deposition as well as cytokine imbalances contribute to immune dysfunction. Interleukin‑9 (IL-9) is a T cell-derived factor preferentially expressed by CD4+ T cells and it has been characterized in human and murine systems. IL-9 targets cells of the lymphoid, myeloid and mast cell lineages, and is likely to contribute to the development of allergic and autoimmune diseases such as asthma, arthritis, multiple sclerosis and experimental autoimmune encephalomyelitis (EAE). Nevertheless, until recently there have been no studies on its role in SLE in humans. In the present study, the mRNA and serum IL-9 levels in the peripheral blood of SLE patients and healthy controls were assessed using real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively. Flow cytometry was used to analyze the percentages of CD4+IL-9+ T cells in SLE patients. Moreover, differences between the groups and the effect of glucocorticoids were analyzed. The results showed that the plasma concentration and mRNA levels of IL-9 were significantly elevated in SLE patients compared with the healthy controls. The percentages of CD4+IL-9+ T cells were also increased in SLE patients. In addition, serum IL-9 levels and the percentages of CD4+IL-9+ T cells were correlated with the SLE disease activity index (SLEDAI). Additionally, the percentages of CD4+IL-9+ T cells and serum IL-9 levels in 8 untreated active SLE patients were decreased at 1, 2 and 3 weeks after treatment with methylprednisolone. In conclusion, we provide evidence that IL-9 is increased in SLE patients. Moreover, it is described for the first time that high expression of IL-9 levels and the percentages of CD4+IL-9+ T cells correlate with disease activity and severity. This suggests an important role of IL-9 in the pathogenesis of SLE.

The role of interleukin-9 in lymphoma

Although much progress has been made in the treatment of lymphomas, the unclear molecular etiology limits its further development. Interleukin-9 (IL-9) was initially described as a growth factor secreted by activated helper T cells type 2 (Th2). Various observations have demonstrated its diverse actions in immune and inflammatory responses. In recent years, a resurgence of interest in IL-9 has been spurred by the expanded identification of its cellular sources and biological targets. Also, the determination of its growth-proliferative and anti-apoptotic activities on multiple transformed cells implies a potential role of this cytokine in tumorigenesis. In this article we review the biologic properties and signal transduction pathways of IL-9, and furthermore discuss its possible role in lymphomagenesis as well as its impact on non-malignant infiltrating cells which are characteristic of the tumor microenvironment.

A naturally processed HLA-DR-bound peptide from the IL-9 receptor alpha of HTLV-1-transformed T cells serves as a T helper epitope

Human T cell leukemia virus type 1 (HTLV-1) induced adult T cell leukemia/lymphoma (ATLL) is usually a fatal lymphoproliferative malignant disease. Thus, the enhancement of T cell immunity to ATLL through the development of therapeutic vaccines using characterized T cell peptide epitopes could be of value. We isolated and characterized HLA-DR-bound peptides from HTLV-1-transformed T cells by fractionating on reverse-phase high performance liquid chromatography and Edman NH(2)-terminal sequencing and were able to identify five independent peptide sequences. One of the identified peptide sequences corresponded to a fragment of the human interleukin-9 receptor alpha (IL-9Rα), which is commonly expressed by HTLV-1-infected T cell lymphoma cells. Using a synthetic peptide corresponding to the identified IL-9Rα sequence, we generated antigen-specific CD4 helper T lymphocytes in vitro, which were restricted by HLA-DR15 or HLA-DR53 molecules and could recognize and kill HTLV-1+, IL-9Rα+ T cell lymphoma cells. These results indicate that IL-9Rα functions as T cell leukemia/lymphoma-associated antigen for CD4 T cells and that synthetic peptides such as the one described here could be used for T cell-based immunotherapy against IL-9Rα positive ATLL.