IL-1 and IL-1 regulatory pathways in cancer progression and therapy

The impact of inflationary cytomegalovirus-specific memory T cells on anti-tumour immune responses in patients with cancer

Human cytomegalovirus (CMV) is a ubiquitous, persistent beta herpesvirus. CMV infection contributes to the accumulation of functional antigen-specific CD8⁺ T-cell pools with an effector-memory phenotype and enrichment of these immune cells in peripheral organs. We review here this 'memory T-cell inflation' phenomenon and associated factors including age and sex. 'Collateral damage' due to CMV-directed immune reactivity may occur in later stages of life - arising from CMV-specific immune responses that were beneficial in earlier life. CMV may be considered an age-dependent immunomodulator and a double-edged sword in editing anti-tumour immune responses. Emerging evidence suggests that CMV is highly prevalent in patients with a variety of cancers, particularly glioblastoma. A better understanding of CMV-associated immune responses and its implications for immune senescence, especially in patients with cancer, may aid in the design of more clinically relevant and tailored, personalized treatment regimens. 'Memory T-cell inflation' could be applied in vaccine development strategies to enrich for immune reactivity where long-term immunological memory is needed, e.g. in long-term immune memory formation directed against transformed cells.

Regulation of IL-1 signaling by the decoy receptor IL-1R2

The pleiotropic cytokine IL-1 mediates its biological functions via association with the signaling receptor IL-1R1. Despite an apparent simplicity in IL-1 signaling activation, multiple negative regulators have been identified. The decoy receptor IL-1R2 (also known as CD121b) can suppress IL-1 maturation, sequester its active forms or hinder the signaling complex assembly. IL-1R2 is differentially expressed among numerous cell types and displays cis- and trans- modes of action. In this review, we link different forms of IL-1R2 (membrane-bound (mIL-1R2), secreted (sIL-1R2), shedded (shIL-1R2), cytoplasmic, and intracellular domain (IL-1R2^ICD) restricted) with their ability to interfere with IL-1, thereby regulating immune responses. We also discuss the intriguing possible function of IL-1R2 as a transcriptional regulator. Finally, we summarize the known impact of IL-1R2 in disease pathogenesis and discuss its potential role in treatment of inflammatory conditions.

Interleukin-1 Beta-A Friend or Foe in Malignancies?

Interleukin-1 beta (IL-1β) is induced by inflammatory signals in a broad number of immune cell types. IL-1β (and IL-18) are the only cytokines which are processed by caspase-1 after inflammasome-mediated activation. This review aims to summarize current knowledge about parameters of regulation of IL-1β expression and its multi-facetted role in pathophysiological conditions. IL-1 signaling activates innate immune cells including antigen presenting cells, and drives polarization of CD4+ T cells towards T helper type (Th) 1 and Th17 cells. Therefore, IL-1β has been attributed a largely beneficial role in resolving acute inflammations, and by initiating adaptive anti-tumor responses. However, IL-1β generated in the course of chronic inflammation supports tumor development. Furthermore, IL-1β generated within the tumor microenvironment predominantly by tumor-infiltrating macrophages promotes tumor growth and metastasis via different mechanisms. These include the expression of IL-1 targets which promote neoangiogenesis and of soluble mediators in cancer-associated fibroblasts that evoke antiapoptotic signaling in tumor cells. Moreover, IL-1 promotes the propagation of myeloid-derived suppressor cells. Using genetic mouse models as well as agents for pharmacological inhibition of IL-1 signaling therapeutically applied for treatment of IL-1 associated autoimmune diseases indicate that IL-1β is a driver of tumor induction and development.

Trial Watch: Immunostimulation with recombinant cytokines for cancer therapy

Cytokines regulate virtually aspects of innate and adaptive immunity, including the initiation, execution and extinction of tumor-targeting immune responses. Over the past three decades, the possibility of using recombinant cytokines as a means to elicit or boost clinically relevant anticancer immune responses has attracted considerable attention. However, only three cytokines have been approved so far by the US Food and Drug Administration and the European Medicines Agency for use in cancer patients, namely, recombinant interleukin (IL)-2 and two variants of recombinant interferon alpha 2 (IFN-α2a and IFN-α2b). Moreover, the use of these cytokines in the clinics is steadily decreasing, mostly as a consequence of: (1) the elevated pleiotropism of IL-2, IFN-α2a and IFN-α2b, resulting in multiple unwarranted effects; and (2) the development of highly effective immunostimulatory therapeutics, such as immune checkpoint blockers. Despite this and other obstacles, research in the field continues as alternative cytokines with restricted effects on specific cell populations are being evaluated. Here, we summarize research preclinical and clinical developments on the use of recombinant cytokines for immunostimulation in cancer patients.