The Half-Life-Extended IL21 can Be Combined With Multiple Checkpoint Inhibitors for Tumor Immunotherapy

Albumin-based strategies to effectively prolong the circulation half-life of small immunomodulatory payloads in cancer therapy

Small immunomodulatory payloads (IMMs) such as peptide vaccines and cytokines have the capability to activate and boost the immune response against cancer. However, their clinical use has often been hindered by their poor stability and short circulating half-lives. To enhance the pharmacokinetic properties of small IMMs and promote their trafficking and accumulation in lymphatic and tumor tissues, a large variety of strategies have been developed. One of the most successful relies on the use of serum albumin (SA), the most abundant protein in the circulatory and lymphatic system. Here, we report a comparative analysis of the different covalent and noncovalent SA-based strategies applied so far to improve the efficacy of small IMMs in cancer therapy.

Tregs ST2 deficiency enhances the abscopal anti-tumor response induced by microwave ablation

BACKGROUND

Thermal ablation (TA), including radiofrequency ablation (RFA) and Microwave ablation (MWA) could reduce tumor burden and can stimulate an immune response, but it cannot maintain a lasting immune response. The alarming cytokine IL-33 is constitutively expressed by epithelial cells, endothelial cells, and fibroblasts, but is released during tissue injury to alert the immune system. The presence of ST2+Tregs in TME may act as a barrier contributing to this phenomenon.

METHODS

In this study, we explored the impact of RFA on the expression of ST2 (also known as IL1RL1) in tumor-infiltrating lymphocytes (TILs). Subsequently, we constructed a Treg cell-specific deletion ST2 mouse model (Foxp3CreIl1rl1fl/fl) and evaluated the genetic phenotypes by flow cytometry. A bilateral dorsal tumor-bearing model was established in Foxp3Cre and Foxp3CreIl1rl1fl/fl mice to explore the anti-tumor effect of MWA. Finally, we used flow cytometry and single-cell transcriptome sequencing (scRNA-seq) to profile CD45+ immune cells within TME.

RESULTS

Our findings suggest that ablation upregulates ST2 expression in Tregs within the contralateral TME. Compared with Foxp3Cre mice, MWA significantly inhibited the growth of contralateral tumors in Foxp3CreIl1rl1fl/fl mice. Its mechanisms include reducing the proportion of Tregs, enhancing the infiltration and effector function of CD8+T cells, increasing the proportion of Effector CD8+T cells, reducing the proportion of Exhausted CD8+T cells, increasing MHC-I molecules in mDC cells and monocytes, and reducing the expression of TAM2 inhibitory molecules and chemokines.

CONCLUSIONS

Blocking IL-33/ST2 pathway in Tregs offers a new strategy for MWA in clinical studies of metastatic cancer.

Multiomics Analysis of Interleukin-21 as a Potential Immunologic and Biomarker in Hepatocellular Carcinoma

Interleukin-21 (IL-21) is an important antitumor cytokine that contributes to the proliferation and differentiation of CD8 + T cells. It has been proven to enhance the response to immune checkpoint inhibitors (ICIs) in various solid tumors. However, its role in hepatocellular carcinoma (HCC) has not yet been clarified. In this research, we aimed to investigate the antitumor effect of IL-21 in HCC and its effect on ICI treatment. Through transcriptome sequencing analysis and immunohistochemistry validation, we found that patients with high IL-21 expression had a better prognosis. HCCs with high expression of IL-21 had higher infiltration of CD8 + T cells, increased expression of immune checkpoints, and an improved response to ICI treatment. In conclusion, IL-21 can enhance the efficacy of ICI treatment and improve the prognosis of patients by promoting the infiltration of CD8 + T cells and the expression of immune checkpoint-related genes.

Stimulating the Antitumor Immune Response Using Immunocytokines: A Preclinical and Clinical Overview

Cytokines are immune modulators which can enhance the immune response and have been proven to be an effective class of immunotherapy. Nevertheless, the clinical use of cytokines in cancer treatment has faced several challenges associated with poor pharmacokinetic properties and the occurrence of adverse effects. Immunocytokines (ICKs) have emerged as a promising approach to overcome the pharmacological limitations observed with cytokines. ICKs are fusion proteins designed to deliver cytokines in the tumor microenvironment by taking advantage of the stability and specificity of immunoglobulin-based scaffolds. Several technological approaches have been developed. This review focuses on ICKs designed with the most impactful cytokines in the cancer field: IL-2, TNFα, IL-10, IL-12, IL-15, IL-21, IFNγ, GM-CSF, and IFNα. An overview of the pharmacological effects of the naked cytokines and ICKs tested for cancer therapy is detailed. A particular emphasis is given on the immunomodulatory effects of ICKs associated with their technological design. In conclusion, this review highlights active ways of development of ICKs. Their already promising results observed in clinical trials are likely to be improved with the advances in targeting technologies such as cytokine/linker engineering and the design of multispecific antibodies with tumor targeting and immunostimulatory functional properties.

From bench to bedside: the past, present and future of IL-21 immunotherapy

As immunotherapy gains momentum as a promising approach for treating several types of cancer, IL-21 has emerged as the latest discovery within the γ chain cytokine family, known for its decisive effects on innate and adaptive immunity and immunopathology. Through the modulation of immune cells, IL-21 has demonstrated significant anti-tumor effects in preclinical studies. The potential of IL-21 in cancer treatment has been explored in phase I and II clinical trials, where it has been utilized both as monotherapy and in combination with other drug agents. Further investigation, alongside larger studies, is necessary before final evaluation and application of IL-21 as immunotherapy. This review aims to summarize these pre-clinical and clinical studies and to discuss the possible future directions of IL-21 immunotherapy development. Such a study may be helpful to accelerate the process of clinical application for IL21 immunotherapy.

Enhanced abscopal anti-tumor response via a triple combination of thermal ablation, IL-21, and PD-1 inhibition therapy

Despite the success of immune checkpoint inhibitors (ICIs) in treating solid tumors, lots of patients remain unresponsive to this therapy. Microwave ablation (MWA) stimulates systemic adaptive immunity against tumor cells by releasing tumor antigens. Additionally, IL-21 has demonstrated importance in stimulating T-cell effector function. The combination of these three therapies-MWA, IL-21, and anti-PD-1 monoclonal antibodies (mAbs)-has yet to be explored in the context of cancer treatment.In this study, we explored the impact of thermal ablation on IL-21R expression in tumor-infiltrating lymphocytes (TILs). Subsequently, we assessed alterations in the tumor microenvironment (TME) and peripheral lymphoid organs. Additionally, we conducted a thorough examination of tumor-infiltrating CD45+ immune cells across various treatment groups using single-cell RNA sequencing (scRNA-seq). Moreover, we determined the potential anti-tumor effects of the triple combination involving MWA, IL-21, and anti-PD-1 mAbs.Our findings revealed that MWA upregulated the expression of IL-21R on various immune cells in the untreated tumors. The combination of MWA with IL-21 exhibited a robust abscopal anti-tumor effect, enhancing the effector function of CD8+ T cells and facilitating dendritic cells' maturation and antigen presentation in the untreated tumor. Notably, the observed abscopal anti-tumor effect resulting from the combination is contingent upon T-cell recirculation, indicating the reliance of systemic adaptive immunity for this treatment regimen. Additionally, the combination of MWA, IL-21, and PD-1 mAbs demonstrated profound abscopal anti-tumor efficacy. Our findings provide support for further clinical investigation into a triple combination therapy involving MWA, IL-21, and ICIs for the treatment of metastatic cancer.

Metabolic adaptations determine whether natural killer cells fail or thrive within the tumor microenvironment

Natural Killer (NK) cells are a top contender in the development of adoptive cell therapies for cancer due to their diverse antitumor functions and ability to restrict their activation against nonmalignant cells. Despite their success in hematologic malignancies, NK cell-based therapies have been limited in the context of solid tumors. Tumor cells undergo various metabolic adaptations to sustain the immense energy demands that are needed to support their rapid and uncontrolled proliferation. As a result, the tumor microenvironment (TME) is depleted of nutrients needed to fuel immune cell activity and contains several immunosuppressive metabolites that hinder NK cell antitumor functions. Further, we now know that NK cell metabolic status is a main determining factor of their effector functions. Hence, the ability of NK cells to withstand and adapt to these metabolically hostile conditions is imperative for effective and sustained antitumor activity in the TME. With this in mind, we review the consequences of metabolic hostility in the TME on NK cell metabolism and function. We also discuss tumor-like metabolic programs in NK cell induced by STAT3-mediated expansion that adapt NK cells to thrive in the TME. Finally, we examine how other approaches can be applied to enhance NK cell metabolism in tumors.

Prediction of immunotherapy responsiveness in melanoma through single-cell sequencing-based characterization of the tumor immune microenvironment

Immune checkpoint inhibitors (ICB) therapy have emerged as effective treatments for melanomas. However, the response of melanoma patients to ICB has been highly heterogenous. Here, by analyzing integrated scRNA-seq datasets from melanoma patients, we revealed significant differences in the TiME composition between ICB-resistant and responsive tissues, with resistant or responsive tissues characterized by an abundance of myeloid cells and CD8+ T cells or CD4+ T cell predominance, respectively. Among CD4+ T cells, CD4+ CXCL13+ Tfh-like cells were associated with an immunosuppressive phenotype linked to immune escape-related genes and negative regulation of T cell activation. We also develop an immunotherapy response prediction model based on the composition of the immune compartment. Our predictive model was validated using CIBERSORTx on bulk RNA-seq datasets from melanoma patients pre- and post-ICB treatment and showed a better performance than other existing models. Our study presents an effective immunotherapy response prediction model with potential for further translation, as well as underscores the critical role of the TiME in influencing the response of melanomas to immunotherapy.

Therapeutic potential of interleukin-21 in cancer

Interleukin-21 (IL-21) is an immunostimulatory cytokine which belongs to the common gamma-chain family of cytokines. It plays an import role in the development, differentiation, proliferation, and activation of immune cells, in particular T and natural killer (NK) cells. Since its discovery in 2000, IL-21 has been shown to regulate both adaptive and immune responses associates with key role in antiviral and antitumor responses. Recent advances indicate IL-21 as a promising target for cancer treatment and encouraging results were obtained in preclinical studies which investigated the potency of IL-21 alone or in combination with other therapies, including monoclonal antibodies, checkpoint inhibitory molecules, oncolytic virotherapy, and adoptive cell transfer. Furthermore, IL-21 showed antitumor effects in the treatment of patients with advanced cancer, with minimal side effects in several clinical trials. In the present review, we will outline the recent progress in IL-21 research, highlighting the potential of IL-21 based therapy as single agent or in combination with other drugs to enhance cancer treatment efficiency.

Interleukin-21 as an adjuvant in cancer immunotherapy: Current advances and future directions

Immunotherapy has revolutionized cancer treatment. However, it's well-recognized that a considerable proportion of patients fail to benefit from immunotherapy, and to improve immunotherapy response is clinically urgent. Insufficient immune infiltration and immunosuppressive tumor microenvironments (TME) are main contributors to immunotherapy resistance. Thus sustaining functional self-renewal capacity for immune cells and subverting immune-suppressive signals are potential strategies for boosting the efficacy of immunotherapy. Interleukin-21 (IL-21), a crucial cytokine, which could enhance cytotoxic function of immune cells and reduces immunosuppressive cells enrichment in TME, shows promising orientations as an immunoadjuvant in tumor immunotherapy. This review focuses on IL-21 in cancer treatment, including function and mechanisms of IL-21, preclinical and clinical studies, and future directions for IL-21-assisted therapies.

Cordycepin remodels the tumor microenvironment of colorectal cancer by down-regulating the expression of PD-L1

PURPOSE

Colorectal cancer, as a common malignant tumor, poses a serious threat to human life. Cordycepin, derived from Cordyceps militaris extract, which was established as a capable inhibitor of tumor growth. Nevertheless, the precise antitumor mechanism of cordycepin in colorectal cancer cells remains elusive.

METHODS

Herein, our initial focus was to explore the tumor-suppressive impact of cordycepin through its influence on various biological functions in murine colorectal cancer cells, conducted by an in vitro setting. First, we investigated the tumor-suppressive effect of cordycepin on the regulation of biological functions in murine colorectal cancer cells in vitro. Furthermore, we evaluated the in vivo antitumor potential of cordycepin using a mouse preclinical tumor model, and further explored the antitumor mechanism.

RESULTS

Our findings revealed that cordycepin effectively inhibit the proliferation, invasion, and migration of murine colon cancer cells. Moreover, there is a substantial reduction in the expression of PD-L1 observed in tumor cells, in response to cordycepin treatment. Collectively, these results demonstrate the significant tumor-suppressive attributes of cordycepin against colorectal cancer. Consequently, our study lays a solid foundation for the potential clinical utilization of cordycepin in cancer therapy.

CONCLUSION

Cordycepin inhibits the biological functions of colorectal cancer cells and suppresses tumor growth by reducing the expression of PD-L1.

The Therapeutic Values of IL-7/IL-7R and the Recombinant Derivatives in Glioma: A Narrative Review

Interleukin-7 (IL-7) is essential for maintaining the immune system's defense functions by regulating the development and homeostasis of lymphocytes. Findings have shown the high efficacy of IL-7/IL-7 receptor (IL-7R)-based immunotherapy on various malignancies, with confirmation in both animal models and humans. In recent years, the progression-free survival and overall survival of patients suffering from gliomas significantly increased by introducing C7R-expressing chimeric antigen receptor (CAR)-T cells and long-acting IL-7 agonists such as NT-I7 (rhIL-7-hyFc, Efineptakin alfa). However, the effect of IL-7-based immunotherapies on the resistance of tumor cells to chemotherapy (when used simultaneously with chemotherapy agents) is still ambiguous and requires further studies. This article first reviews the pathophysiological roles of IL-7/IL-7R in tumors, focusing on gliomas. Subsequently, it discusses the therapeutic values of IL-7/IL-7R and the recombinant derivatives in gliomas.

Synergism Between IL21 and Anti-PD-1 Combination Therapy is Underpinned by the Coordinated Reprogramming of the Immune Cellular Network in the Tumor Microenvironment

T cell-stimulating cytokines and immune checkpoint inhibitors (ICI) are an ideal combination for increasing response rates of cancer immunotherapy. However, the results of clinical trials have not been satisfying. It is important to understand the mechanism of synergy between these two therapeutic modalities. Here, through integrated analysis of multiple single-cell RNA sequencing (scRNA-seq) datasets of human tumor-infiltrating immune cells, we demonstrate that IL21 is produced by tumor-associated T follicular helper cells and hyperactivated/exhausted CXCL13+CD4+ T cells in the human tumor microenvironment (TME). In the mouse model, the hyperactivated/exhausted CD4+ T cell-derived IL21 enhances the helper function of CD4+ T cells that boost CD8+ T cell-mediated immune responses during PD-1 blockade immunotherapy. In addition, we demonstrated that IL21's antitumor activity did not require T-cell trafficking. Using scRNA-seq analysis of the whole tumor-infiltrating immune cells, we demonstrated that IL21 treatment in combination with anti-PD-1 blockade synergistically drives tumor antigen-specific CD8+ T cells to undergo clonal expansion and differentiate toward the hyperactive/exhausted functional state in the TME. In addition, IL21 treatment and anti-PD-1 blockade synergistically promote dendritic cell (DC) activation and maturation to mature DC as well as monocyte to type 1 macrophage (M1) differentiation in the TME. Furthermore, the combined treatment reprograms the immune cellular network by reshaping cell-cell communication in the TME. Our study establishes unique mechanisms of synergy between IL21 and PD-1-based ICI in the TME through the coordinated promotion of type 1 immune responses.

Significance

This study reveals how cytokine and checkpoint inhibitor therapy can be combined to increase the efficacy of cancer immunotherapy.

Anti-Claudin18.2-IL-21 fusion protein bifunctional molecule has more powerful anti-tumor effect and better safety

Antibody or antibody-like protein drugs related to tumor immunotherapy are now widely used. Here, we describe an antibody-fusion protein drug IMAB362-mIL-21 with mouse IL-21 (mIL-21) fused into the C-terminal domain of IMAB362 (a clinical antibody drug against Claudin18.2), that we expect can achieve tumor targeting and activate local anti-tumor immune response more effectively, while reducing the systemic side effects of individual cytokines. In vitro assays comparing the fusion protein IMAB362-mIL-21 to IMAB362 and mIL-21, IMAB362-mIL-21 was able to recognize its cognate antigen Claudin18.2 and natural receptor mIL-21R with similar binding affinities, mediate equivalent ADCC activity and activate IL-21R-mediated downstream signal pathway. In in vivo assays, IMAB362-mIL-21 produced stronger anti-tumor effects compared with IMAB362 or mIL-21 or their combination at equimolar concentrations. Moreover, according to routine blood indicators, mIL-21-Fc and the combined treatment group had significant decreases (P < 0.01) in red blood cells (RBC), hemoglobin (HGB) and hematocrit (HCT), while the IMAB362-mIL-21 group did not. The above results have shown that IMAB362-mIL-21 can produce better anti-tumor effects without obvious hematological toxicity, which is sufficient to show that this kind of antibody-cytokine protein has better application value than IMAB362 or IL-21 as single drugs or in combination. Therefore, this bifunctional molecule combined tumor-targeting and immune activation effectively and has good application prospects.

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.

Extracellular vesicle-based checkpoint regulation and immune state in cancer

Tumor cells exploit several mechanisms for hijacking an immunosuppressive tumor ecosystem in order to evade immune surveillance and to progress toward metastasis. Equipment of extracellular vesicles (EVs) with checkpoints is an example of cancer control over anti-tumor responses from immune system. Programmed death-ligand 1 (PD-L1) is a checkpoint highly expressed in a tumor at progressive stage. Interactions between PD-L1 with its receptor programmed death-1 receptor (PD-1) expressed on T cells will block the effector function of CD8⁺ T cells, known as one of the most important defensive cells against cancer. Evaluation of circulatory exosomal PD-L1 can be a prognostic biomarker in tumor diagnosis and responses to the immune checkpoint inhibitor (ICI) therapy, and can be considered as a tool in clinical practice for exploiting personalized therapy. Cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) is also a checkpoint that its engagement with CD80/CD86 expressed on antigen-presenting cells (APCs), such as dendritic cells (DCs) hamper the priming phase of CD4⁺ and CD8⁺ T cells. Harvesting EVs from tumor and their modification with desired anti-checkpoint antibodies can be a promising strategy in cancer immunotherapy. The aim of this review is to discuss about EV roles in checkpoint regulation, cancer diagnosis and ICI responses, and to survey possible application of such vesicles in cancer immunotherapy.

The Role of Inflammatory Cytokines in the Pathogenesis of Colorectal Carcinoma—Recent Findings and Review

The inflammatory process plays a significant role in the development of colon cancer (CRC). Intestinal cytokine networks are critical mediators of tissue homeostasis and inflammation but also impact carcinogenesis at all stages of the disease. Recent studies suggest that inflammation is of greater importance in the serrated pathway than in the adenoma-carcinoma pathway. Interleukins have gained the most attention due to their potential role in CRC pathogenesis and promising results of clinical trials. Malignant transformation is associated with the pro-tumorigenic and anti-tumorigenic cytokines. The harmony between proinflammatory and anti-inflammatory factors is crucial to maintaining homeostasis. Immune cells in the tumor microenvironment modulate immune sensitivity and facilitate cancer escape from immune surveillance. Therefore, clarifying the role of underlying cytokine pathways and the effects of their modulation may be an important step to improve the effectiveness of cancer immunotherapy.

Roles for macrophage-polarizing interleukins in cancer immunity and immunotherapy

Macrophages are the most abundant and one of the most critical cells of tumor immunity. They provide a bridge between innate and adaptive immunity through releasing cytokines into the tumor microenvironment (TME). A number of interleukin (IL) cytokine family members is involved in shaping the final phenotype of macrophages toward either a classically-activated pro-inflammatory M1 state with anti-tumor activity or an alternatively-activated anti-inflammatory M2 state with pro-tumor activity. Shaping TME macrophages toward the M1 phenotype or recovering this phenotypic state may offer a promising therapeutic approach in patients with cancer. Here, we focus on the impact of macrophage-polarizing ILs on immune cells and IL-mediated cellular cross-interactions within the TME. The key aim of this review is to define therapeutic schedules for addressing ILs in cancer immunotherapy based on their multi-directional impacts in such a milieu. Gathering more knowledge on this area is also important for defining adverse effects related to cytokine therapy and addressing them for reinforcing the efficacy of immunotherapy against cancer.