A homodimeric IL-15 superagonist F4RLI with easy preparation, improved half-life, and potent antitumor activities

A tumor-conditional IL-15 safely synergizes with immunotherapy to enhance antitumor immune responses

It is a challenge to invigorate tumor-infiltrating lymphocytes without causing immune-related adverse events, which also stands as a primary factor contributing to resistance against cancer immunotherapies. Interleukin (IL)-15 can potently promote expansion and activation of T cells, but its clinical use has been limited by dose-limiting toxicities. In this study, we develop a tumor-conditional IL-15 (pro-IL-15), which masks IL-15 with steric hindrance caused by Fc fragment and IL-15Rα-sushi domain. Upon reaching the tumor site, it can be cleaved by tumor-associated proteases to release an IL-15 superagonist, resulting in potent antitumor activities. Systemic delivery of pro-IL-15 demonstrates significantly reduced toxicity but uncompromised antitumor efficacy. Pro-IL-15 can yield better effectors and vitalize terminally exhausted CD8+ T cells to overcome checkpoint blockade resistance. Moreover, pro-IL-15 promotes chemotaxis and activation of adoptive T cells, leading to eradication of advanced solid tumors and durable cures. Furthermore, pro-IL-15 shows promise for synergizing with other immunotherapies like IL-12 and oncolytic virus by improving the CD8/Treg ratio and interferon-γ levels, resulting in substantial regression of both local and metastatic cold tumors. Collectively, our results suggest that pro-IL-15 represents a compelling strategy for overcoming resistance to current immunotherapies while avoiding toxicities.

IL-15 as a key regulator in NK cell-mediated immunotherapy for cancer: From bench to bedside

Interleukin 15 (IL-15) has emerged as a crucial factor in the relationship between natural killer (NK) cells and immunotherapy for cancer. This review article aims to provide a comprehensive understanding of the role of IL-15 in NK cell-mediated immunotherapy. First, the key role of IL-15 signaling in NK cell immunity is discussed, highlighting its regulation of NK cell functions and antitumor properties. Furthermore, the use of IL-15 or its analogs in clinical trials as a therapeutic strategy for various cancers, including the genetic modification of NK cells to produce IL-15, has been explored. The potential of IL-15-based therapies, such as chimeric antigen receptor (CAR) T and NK cell infusion along with IL-15 in combination with checkpoint inhibitors and other treatments, has been examined. This review also addresses the challenges and advantages of incorporating IL-15 in cell-based immunotherapy. Additionally, unresolved questions regarding the detection and biological significance of the soluble IL-15/IL-15Rα complex, as well as the potential role of IL-15/IL-15Rα in human cancer and the immunological consequences of prolonged exposure to soluble IL-15 for NK cells, are discussed.

Mitotic MTH1 inhibitor TH1579 induces PD-L1 expression and inflammatory response through the cGAS-STING pathway

The mitotic MTH1 inhibitor TH1579 is a dual inhibitor that inhibits mitosis and incorporation of oxidative DNA damage and leads to cancer-specific cell death. The response to immune checkpoint inhibitor (ICI) treatment is often augmented by DNA damaging agents through the cGAS-STING pathway. This study investigates whether TH1579 can improve the efficacy of immune checkpoint blockades through its immunomodulatory properties. Various human and murine cancer cell lines were treated with mitotic MTH1i TH1579, and the expression of PD-L1 and T-cell infiltration-related chemokines was analysed by flow cytometry and real-time qPCR. Syngeneic mouse models were established to examine the combined effect of TH1579 and PD-L1 blockade. In our investigation, we found that TH1579 upregulates PD-L1 expression at both the protein and mRNA levels in human cancer cell lines. However, in murine cell lines, the increase was less pronounced. An in vivo experiment in a syngeneic mouse melanoma model showed that TH1579 treatment significantly increased the efficacy of atezolizumab, an anti-PD-L1 antibody, compared to vehicle or atezolizumab monotherapy. Furthermore, TH1579 exhibited immune-modulatory properties, elevating cytokines such as IFN-β and chemokines including CCL5 and CXCL10, in a cGAS-STING pathway-dependent manner. In conclusion, TH1579 has the potential to improve ICI treatment by modulating immune checkpoint-related proteins and pathways.

Cancer immunotherapy focusing on the role of interleukins: A comprehensive and updated study

Cytokines bind to specific receptors on target cells to activate intracellular signaling pathways that control diverse cellular functions, such as proliferation, differentiation, migration, and death. They are essential for the growth, activation, and operation of immune cells and the control of immunological reactions to pathogens, cancer cells, and other dangers. Based on their structural and functional properties, cytokines can be roughly categorized into different families, such as the tumor necrosis factor (TNF) family, interleukins, interferons, and chemokines. Leukocytes produce interleukins, a class of cytokines that have essential functions in coordinating and communicating with immune cells. Cancer, inflammation, and autoimmunity are immune-related disorders brought on by dysregulation of cytokine production or signaling. Understanding cytokines' biology to create novel diagnostic, prognostic, and therapeutic methods for various immune-related illnesses is crucial. Different immune cells, including T cells, B cells, macrophages, and dendritic cells, and other cells in the body, including epithelial cells and fibroblasts, generate and secrete interleukins. The present study's main aim is to fully understand interleukins' roles in cancer development and identify new therapeutic targets and strategies for cancer treatment.