Interleukin 21 - its potential role in the therapy of B-cell lymphomas

Enhanced chemoimmunotherapy of breast cancer in mice by apolipoprotein A1-modified doxorubicin liposomes combined with interleukin-21

Backgroud: Breast cancer is a prevalent malignancy among women, with triple-negative breast cancer (TNBC) comprising approximately 15-20% of all cases, possessing high invasiveness, drug resistance and poor prognosis. Chemotherapy, the main treatment for TNBC, is limited by toxicity and drug resistance. Apolipoprotein A1 modified doxorubicin liposome (ApoA1-lip/Dox) was constructed in our previous study, with promising anti-tumour effect and improved safety been proved. However, during long-term administration, the problem of cumulative toxicity and insufficient tumour inhibition is still inevitable. Interleukin-21 is a small molecule protein secreted by T cells with various immune regulatory functions. IL-21 has significantly curative effects in numerous solid tumours, but it has the disadvantages of low response rate and short half-life. The combination of chemotherapy and immunotherapy has received increasing attention.Purpose: In this study, ApoA1 drug loading system and long-acting IL-21 are innovatively combined for tumour treatment.Methods: We combined ApoA1-lip/Dox and IL-21 for treatment and evaluated their impact on tumor-infiltrating lymphocytes and CD8+ T and NK cell cytotoxicity.Results: Combined administration significantly improved the tumour-infiltrating lymphocytes and enhanced the cytotoxicity of CD8+ T and NK cells. The combination of ApoA1-lip/Dox and IL-21 exhibits significantly enhanced anti-tumour efficacy with lower toxicity of ApoA1-lip/Dox, providing a new strategy for TNBC treatment with enhanced anti-tumour response and reduced toxicity.

Defining the Basal and Immunomodulatory Mediator-Induced Phosphoprotein Signature in Pediatric B Cell Acute Lymphoblastic Leukemia (B-ALL) Diagnostic Samples

It is theorized that dysregulated immune responses to infectious insults contribute to the development of pediatric B-ALL. In this context, our understanding of the immunomodulatory-mediator-induced signaling responses of leukemic blasts in pediatric B-ALL diagnostic samples is rather limited. Hence, in this study, we defined the signaling landscape of leukemic blasts, as well as normal mature B cells and T cells residing in diagnostic samples from 63 pediatric B-ALL patients. These samples were interrogated with a range of immunomodulatory-mediators within 24 h of collection, and phosflow analyses of downstream proximal signaling nodes were performed. Our data reveal evidence of basal hyperphosphorylation across a broad swath of these signaling nodes in leukemic blasts in contrast to normal mature B cells and T cells in the same sample. We also detected similarities in the phosphoprotein signature between blasts and mature B cells in response to IFNγ and IL-2 treatment, but significant divergence in the phosphoprotein signature was observed between blasts and mature B cells in response to IL-4, IL-7, IL-10, IL-21 and CD40 ligand treatment. Our results demonstrate the existence of both symmetry and asymmetry in the phosphoprotein signature between leukemic and non-leukemic cells in pediatric B-ALL diagnostic samples.

EBV dUTPase: A Novel Modulator of Inflammation and the Tumor Microenvironment in EBV-Associated Malignancies

There is increasing evidence that put into question the classical dogma that the Epstein-Barr virus (EBV) exists in cells as either a lytic virus in which new progeny is produced or in a latent state in which no progeny is produced. Notably, a third state has now been described, known as the abortive-lytic phase, which is characterized by the expression of some immediate early (IE) and early (E) genes, but no new virus progeny is produced. While the function of these IE and E gene products is not well understood, several recent studies support the concept they may contribute to tumor promotion by altering the tumor microenvironment (TME). The mechanisms by which these viral gene products may contribute to tumorigenesis remain unclear; however, it has been proposed that some of them promote cellular growth, immune evasion, and/or inhibit apoptosis. One of these EBV early gene products is the deoxyuridine triphosphate nucleotidohydrolase (dUTPase) encoded by BLLF3, which not only contributes to the establishment of latency through the production of activin A and IL-21, but it may also alter the TME, thus promoting oncogenesis.

Evolution of developmental and comparative immunology in poultry: The regulators and the regulated

Avian has a unique immune system that evolved in response to environmental pressures in all aspects of innate and adaptive immune responses, including localized and circulating lymphocytes, diversity of immunoglobulin repertoire, and various cytokines and chemokines. All of these attributes make birds an indispensable vertebrate model for studying the fundamental immunological concepts and comparative immunology. However, research on the immune system in birds lags far behind that of humans, mice, and other agricultural animal species, and limited immune tools have hindered the adequate application of birds as disease models for mammalian systems. An in-depth understanding of the avian immune system relies on the detailed studies of various regulated and regulatory mediators, such as cell surface antigens, cytokines, and chemokines. Here, we review current knowledge centered on the roles of avian cell surface antigens, cytokines, chemokines, and beyond. Moreover, we provide an update on recent progress in this rapidly developing field of study with respect to the availability of immune reagents that will facilitate the study of regulatory and regulated components of poultry immunity. The new information on avian immunity and available immune tools will benefit avian researchers and evolutionary biologists in conducting fundamental and applied research.

Anti-fibrotic effect of extracellular vesicles derived from tea leaves in hepatic stellate cells and liver fibrosis mice

Background

Activation of hepatic stellate cells (HSCs) is essential for the pathogenesis of liver fibrosis, there is no effective drug used to prevent or reverse the fibrotic process.

Methods

With human hepatic stellate cell line LX-2 and mouse model of CCl₄-induced liver fibrosis, we investigated the anti-fibrotic effect to liver fibrosis of extracellular vesicles (EVs) extracted from tea leaves through cytological tests such as cell proliferation, cell migration, and cell fibrotic marker.

Results

It was found that tea-derived EVs (TEVs) inhibited HSCs activation. In CCl₄-induced liver fibrosis model, TEVs treatment can significantly improve the pathological changes of liver tissue, inhibit collagen deposition, reduce the number of lipid droplets in liver tissue, and reduce serum AST and ALT levels. In addition, TEVs inhibited TGF-β1 signaling and miR-44 in TEVs had the potential inhibitory effect on liver fibrosis.

Conclusions

Taken together, our work suggesting that TEVs are novel therapeutic potential for liver fibrosis.

Harnessing natural killer cells for cancer immunotherapy: dispatching the first responders

Natural killer (NK) cells have crucial roles in the innate immunosurveillance of cancer and viral infections. They are 'first responders' that can spontaneously recognize abnormal cells in the body, rapidly eliminate them through focused cytotoxicity mechanisms and potently produce pro-inflammatory cytokines and chemokines that recruit and activate other immune cells to initiate an adaptive response. From the initial discovery of the diverse cell surface receptors on NK cells to the characterization of regulatory events that control their function, our understanding of the basic biology of NK cells has improved dramatically in the past three decades. This advanced knowledge has revealed increased mechanistic complexity, which has opened the doors to the development of a plethora of exciting new therapeutics that can effectively manipulate and target NK cell functional responses, particularly in cancer patients. Here, we summarize the basic mechanisms that regulate NK cell biology, review a wide variety of drugs, cytokines and antibodies currently being developed and used to stimulate NK cell responses, and outline evolving NK cell adoptive transfer approaches to treat cancer.

CXCL13 expressed on inflamed cerebral blood vessels recruit IL-21 producing TFH cells to damage neurons following stroke

BACKGROUND

Ischemic stroke is a leading cause of mortality worldwide, largely due to the inflammatory response to brain ischemia during post-stroke reperfusion. Despite ongoing intensive research, there have not been any clinically approved drugs targeting the inflammatory component to stroke. Preclinical studies have identified T cells as pro-inflammatory mediators of ischemic brain damage, yet mechanisms that regulate the infiltration and phenotype of these cells are lacking. Further understanding of how T cells migrate to the ischemic brain and facilitate neuronal death during brain ischemia can reveal novel targets for post-stroke intervention.

METHODS

To identify the population of T cells that produce IL-21 and contribute to stroke, we performed transient middle cerebral artery occlusion (tMCAO) in mice and performed flow cytometry on brain tissue. We also utilized immunohistochemistry in both mouse and human brain sections to identify cell types and inflammatory mediators related to stroke-induced IL-21 signaling. To mechanistically demonstrate our findings, we employed pharmacological inhibitor anti-CXCL13 and performed histological analyses to evaluate its effects on brain infarct damage. Finally, to evaluate cellular mechanisms of stroke, we exposed mouse primary neurons to oxygen glucose deprivation (OGD) conditions with or without IL-21 and measured cell viability, caspase activity and JAK/STAT signaling.

RESULTS

Flow cytometry on brains from mice following tMCAO identified a novel population of cells IL-21 producing CXCR5+ CD4+ ICOS-1+ T follicular helper cells (TFH) in the ischemic brain early after injury. We observed augmented expression of CXCL13 on inflamed brain vascular cells and demonstrated that inhibition of CXCL13 protects mice from tMCAO by restricting the migration and influence of IL-21 producing TFH cells in the ischemic brain. We also illustrate that neurons express IL-21R in the peri-infarct regions of both mice and human stroke tissue in vivo. Lastly, we found that IL-21 acts on mouse primary ischemic neurons to activate the JAK/STAT pathway and induce caspase 3/7-mediated apoptosis in vitro.

CONCLUSION

These findings identify a novel mechanism for how pro-inflammatory T cells are recruited to the ischemic brain to propagate stroke damage and provide a potential new therapeutic target for stroke.

Cytokine Based Immunotherapy for Cancer and Lymphoma: Biology, Challenges and Future Perspectives

Cytokines regulate both the innate and adaptive immune responses to cancer. Although antitumor activity has been seen for several cytokines in preclinical models, they have had limited success as single therapeutic agents in clinical trials of cancer immunotherapy. However, the possible combinations of cytokines with other immune therapeutics and the advancement in genetic engineering, synthetic biology and cellular and immune therapy has led to the revival of interest in cytokines as anticancer agents. This article will review several immunostimulatory cytokines with anticancer activity, focusing on the those that have been studied in treatment of lymphoma and highlighting recent advances of potential clinical relevance.

The PD-1/PD-L1 Checkpoint in Normal Germinal Centers and Diffuse Large B-Cell Lymphomas

Besides a recognized role of PD-1/PD-L1 checkpoint in anti-tumour immune evasion, there is accumulating evidence that PD-1/PD-L1 interactions between B and T cells also play an important role in normal germinal center (GC) reactions. Even when smaller in number, T follicular helper cells (TFH) and regulatory T (TFR) or B (Breg) cells are involved in positive selection of GC B cells and may result critical in the lymphoma microenvironment. Here, we discuss a role of PD-1/PD-L1 during tumour evolution in diffuse large B cell lymphoma (DLBCL), a paradigm of GC-derived lymphomagenesis. We depict a progression model, in two phases, where malignant B cells take advantage of positive selection signals derived from correct antigen-presentation and PD-1/PD-L1 inter-cellular crosstalks to survive and initiate tumour expansion. Later, a constant pressure for the accumulation of genetic/epigenetic alterations facilitates that DLBCL cells exhibit higher PD-L1 levels and capacity to secrete IL-10, resembling Breg-like features. As a result, a complex immunosuppressive microenvironment is established where DLBCL cells sustain proliferation and survival by impairing regulatory control of TFR cells and limiting IL-21-mediated anti-tumour functions of TFH cells and maximize the use of PD-1/PD-L1 signaling to escape from CD8+ cytotoxic activity. Integration of these molecular and cellular addictions into a framework may contribute to the better understanding of the lymphoma microenvironment and contribute to the rationale for novel PD-1/PD-L1-based combinational immunotherapies in DLBCL.

IL-21 Stimulates the expression and activation of cell cycle regulators and promotes cell proliferation in EBV-positive diffuse large B cell lymphoma

The clinical features of EBV-positive diffuse large B cell lymphoma (DLBCL) indicate a poorer prognosis than EBV-negative DLBCL. Currently, there is no efficacious drug for EBV-positive DLBCL. The cytokine interleukin-21 (IL-21) has been reported to be pro-apoptotic in DLBCL cell lines and is being explored as a new therapeutic strategy for this type of lymphomas. However, our previous studies showed that IL-21 stimulation of EBV-positive DLBCL cell lines leads to increased proliferation. Here, analysis of a rare clinical sample of EBV-positive DLBCL, in combination with a NOD/SCID mouse xenograft model, confirmed the effect of IL-21 on the proliferation of EBV-positive DLBCL cells. Using RNA-sequencing, we identified the pattern of differentially-expressed genes following IL-21 treatment and verified the expression of key genes at the protein level using western blotting. We found that IL-21 upregulates expression of the host MYC and AP-1 (composed of related Jun and Fos family proteins) and STAT3 phosphorylation, as well as expression of the viral LMP-1 protein. These proteins are known to promote the G1/S phase transition to accelerate cell cycle progression. Furthermore, in NOD/SCID mouse xenograft model experiments, we found that IL-21 treatment increases glucose uptake and angiogenesis in EBV-positive DLBCL tumours. Although more samples are needed to validate these observations, our study reconfirms the adverse effects of IL-21 on EBV-positive DLBCL, which has implications for the drug development of DLBCL.

Adenovirus-mediated overexpression of interleukin-21 regulates the development of oral squamous cell carcinoma in vitro

Interleukin-21 (IL-21) is an important cytokine that is currently being investigated for its potential use in tumor immunotherapy in the future. In tumor cells, IL-21 stimulates the immune response by increasing the cytotoxic activity of natural killer cells, B cells and CD8⁺ T cells, which in turn induces the apoptosis of tumor cells. The therapeutic effects of IL-21 have been investigated in several types of disease and numerous clinical trials are in progress. The aim of the present study was to determine the role of IL-21 in oral squamous cell carcinoma (OSCC) in vitro. IL-21 expression was detected in OSCC tissues via RT-qPCR, western blotting and immunohistochemistry analyses. The results demonstrated that IL-21 protein expression decreased in OSCC tissues. IL-21 was overexpressed using adenovirus in CAL-27 cells. The Cell Counting Kit-8 assay demonstrated that overexpression of IL-21 inhibited cell proliferation. Furthermore, overexpression of IL-21 inhibited cell migration, detected by the wound healing assay, and promoted cell apoptosis, detected by TUNEL staining and flow cytometry analysis. The results demonstrated that overexpression of IL-21 inhibited activation of the JNK signaling pathway. In conclusion, the findings of the present study suggest that IL-21 may function as a potent antitumor agent in OSCC.

Beclin-1 as a neutrophil-specific immune checkpoint

Neutrophils are early wound healing and inflammation regulators that, due to functional plasticity, can adopt either pro- or antitumor functions. Until recently, beclin-1 was a protein known mainly for its role as a critical regulator of autophagy. In this issue of the JCI, Tan et al. describe the effects of the beclin-1 conditional myeloid cell-specific deletion in mice, in which immunostimulation resulted in hypersensitive neutrophils. The chronic proinflammatory effect of these neutrophils triggered spontaneous B cell malignancies to develop. Such tumorigenic effects were mediated primarily by IL-21 and CD40 signaling, leading to the upregulation of tolerogenic molecules, such as IL-10 and PD-L1. The authors went on to examine samples derived from patient lymphoid malignancies and showed that beclin-1 expression in neutrophils positively correlated with pre-B cell leukemia/lymphoma. Overall, the study provides an elegant model for neutrophil-driven carcinogenesis and identifies potential targets for immunotherapy of B cell malignancies.

Interleukin-21 receptor gene polymorphism is associated with hepatitis B virus-related hepatocellular carcinoma in Chinese patients

Background

We investigated the relationship between hepatitis B virus (HBV)‐related pathogenesis and single nucleotide polymorphisms (SNPs) in interleukin‐21 (IL‐21)‐JAK‐STAT signaling pathway genes.

Methods

We used the high‐resolution melting (HRM) method to genotype five SNPs (IL‐21 rs2221903, IL‐21 rs4833837, IL‐21 receptor (IL‐21R) rs2285452, JAK3 rs3008, and STAT3 rs1053023) in 546 HBV‐infected patients and 353 healthy Chinese subjects. The HBV‐infected patients were further divided into subgroups based on the HBV‐related pathologies: chronic hepatitis B (CHB), HBV‐related liver cirrhosis (LC), and HBV‐related hepatocellular carcinoma (HCC).

Results

There were no significant differences in the genotype and allele distributions of the five SNPs between the HBV‐infected patients and healthy subjects. The genotype and allele frequencies were similar in the two groups for IL‐21 rs2221903 (A>G, P = 0.83 and 0.67), rs4833837 (A>G, P = 0.80 and 0.49), IL‐21R rs2285452 (G>A, P = 0.25 and 0.68), STAT3 rs1053023 (A>G, P = 1.00 and 0.96), and JAK3 rs3008 (C>T, P = 0.32 and 0.54). However, patients with the IL‐21R rs2285452 AA genotype were more susceptible to HBV‐related HCC than those with the IL‐21R rs2285452 GA/GG genotype (P = 0.03, OR = 3.27, 95% CI = 1.16‐9.20). The serological marker model of “HBsAg+, HBeAg+, HBcAb+” was predominant among patients with HBV infection. However, there was no association between the genotype's distribution of the five SNPs and the serological marker models (P > 0.05).

Conclusions

These findings demonstrate that the IL‐21R rs2285452 AA genotype increases the risk of HBV‐related HCC in Chinese patients.

Genotype-related variations in proinflammatory and regulatory cytokine levels in treated and treatment-naive HCV-infected patients

Hepatitis C virus (HCV) modulates immune-related inflammatory responses to induce milder reactions leading to virus persistence. In this regard, the present study aimed to investigate the link between the HCV genotypes and the proinflammatory and regulatory cytokine levels. Ninety patients with hepatitis C infection (68 treatment-naive and 22 treated patients) and 76 healthy blood donors were studied. The serum levels of IFN-γ, IL-10, IL-17A, and IL-21 were measured by ELISA in the patients and healthy controls. IL-10, IL-17A, and IL-21 levels were significantly higher in HCV patients than in the healthy controls. The same cytokines were also higher in genotype 3a-infected patients compared with genotype 1a-infected patients. Interestingly, in treated patients, lower serum levels of IL-17A and IL-21 were detected in G3a-infected individuals, but not in those infected with G1a. G3a viral load displayed a significant correlation with IL-21 and IL-17A levels. In addition, G1a viral load correlated with IL-10 levels. In G3a-infected patients, a significant association was found between IL-17A serum levels and ALT. We found differences in IL-21 and IL-17A serum levels among HCV-infected patients which were genotype dependent. Since Th17-associated cytokines are associated with the progression of liver disease in HCV patients, IL-17A and IL-21 can be used as important biological markers for evaluating the immunopathogenesis of chronic hepatitis. Our results suggest that HCV G3a along with immune responses such as cytokines in HCV patients should be taken into account when interpreting clinical data and IFN-based therapeutic response.

Anti-CD20-interleukin-21 fusokine targets malignant B cells via direct apoptosis and NK-cell–dependent cytotoxicity

Delivering IL-21 to tumor B cells by fusion with anti-CD20 antibody (αCD20-IL-21 fusokine) is a potent antilymphoma therapeutic strategy. αCD20-IL-21 fusokine demonstrated superior antilymphoma activity compared with its individual components.

An Ocular Protein Triad Can Classify Four Complex Retinal Diseases

Retinal diseases generally are vision-threatening conditions that warrant appropriate clinical decision-making which currently solely dependents upon extensive clinical screening by specialized ophthalmologists. In the era where molecular assessment has improved dramatically, we aimed at the identification of biomarkers in 175 ocular fluids to classify four archetypical ocular conditions affecting the retina (age-related macular degeneration, idiopathic non-infectious uveitis, primary vitreoretinal lymphoma, and rhegmatogenous retinal detachment) with one single test. Unsupervised clustering of ocular proteins revealed a classification strikingly similar to the clinical phenotypes of each disease group studied. We developed and independently validated a parsimonious model based merely on three proteins; interleukin (IL)-10, IL-21, and angiotensin converting enzyme (ACE) that could correctly classify patients with an overall accuracy, sensitivity and specificity of respectively, 86.7%, 79.4% and 92.5%. Here, we provide proof-of-concept for molecular profiling as a diagnostic aid for ophthalmologists in the care for patients with retinal conditions.