The yin and yang of co-inhibitory receptors: toward anti-tumor immunity without autoimmunity.
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ABSTRACT: Co-inhibitory receptors are important regulators of T-cell function that define the balance between tolerance and autoimmunity. The immune regulatory function of co-inhibitory receptors, including CTLA-4, PD-1, TIM-3, TIGIT, and LAG-3, was first discovered in the setting of autoimmune disease models, in which their blockade or deficiency resulted in induction or exacerbation of the disease. Later on, co-inhibitory receptors on lymphocytes have also been found to influence outcomes in tumor and chronic viral infection settings. These receptors suppress T-cell function in the tumor microenvironment (TME), thereby making the T cells dysfunctional. Based on this observation, blockade of co-inhibitory receptors (also known as checkpoint molecules) has emerged as a successful treatment option for a number of human cancers. However, severe autoimmune-like side effects limit the use of therapeutics that block individual or combinations of co-inhibitory receptors for cancer treatment. In this review we provide an overview of the role of co-inhibitory receptors in autoimmunity and anti-tumor immunity. We then discuss current approaches and future directions to leverage our knowledge of co-inhibitory receptors to target them in tumor immunity without inducing autoimmunity.
Project description:Yin and Yang are two complementary forces that together describe the nature of real-world elements. Yin is the dark side; Yang is the light side. We describe microRNAs having both Yin and Yang characteristics because they can contribute to normal function (Yang) but also to autoimmunity, myeloproliferation, and cancer (Yin). We have been working on a number of microRNAs that have these dual characteristics and here we focus on two, miR-125b and miR-146a. We have concentrated on these two RNAs because we have very extensive knowledge of them, much of it from our laboratory, and also because they provide a strong contrast: the effects of overexpression of miR-125b are rapid, suggesting that it acts directly, whereas the effects of miR-146a are slow to develop, suggesting that they arise from chronic alterations in cellular behavior.
Project description:In the past decade, the power of harnessing T-cell co-signaling pathways has become increasingly understood to have significant clinical importance. In cancer immunotherapy, the field has concentrated on two related modalities: First, targeting cancer antigens through highly activated chimeric antigen T cells (CAR-Ts) and second, re-animating endogenous quiescent T cells through checkpoint blockade. In each of these strategies, the therapeutic goal is to re-ignite T-cell immunity, in order to eradicate tumors. In transplantation, there is also great interest in targeting T-cell co-signaling, but with the opposite goal: in this field, we seek the Yin to cancer immunotherapy's Yang, and focus on manipulating T-cell co-signaling to induce tolerance rather than activation. In this review, we discuss the major T-cell signaling pathways that are being investigated for tolerance induction, detailing preclinical studies and the path to the clinic for many of these molecules. These include blockade of co-stimulation pathways and agonism of coinhibitory pathways, in order to achieve the delicate state of balance that is transplant tolerance: a state which guarantees lifelong transplant acceptance without ongoing immunosuppression, and with preservation of protective immune responses. In the context of the clinical translation of immune tolerance strategies, we discuss the significant challenge that is embodied by the fact that targeted pathway modulators may have opposing effects on tolerance based on their impact on effector vs regulatory T-cell biology. Achieving this delicate balance holds the key to the major challenge of transplantation: lifelong control of alloreactivity while maintaining an otherwise intact immune system.
Project description:Pentraxins are a family of multimeric proteins characterized by the presence of a pentraxin signature in their C-terminus region. Based on the primary structure, pentraxins are divided into short and long pentraxin: C-reactive protein (CRP) is the prototype of the short pentraxin subfamily while pentraxin 3 (PTX3) is the prototypic long pentraxin. Despite these two molecules exert similar fundamental actions in the regulation of innate immune and inflammatory responses, several differences exist between CRP and PTX3, including gene organization, protein oligomerization and expression pattern. The pathophysiological roles of PTX3 have been investigated using genetically modified mice since PTX3 gene organization and regulation are well conserved between mouse and human. Such in vivo studies figured out that PTX3 mainly have host-protective effects, even if it could also exert negative effects under certain pathophysiologic conditions. Here we will review the general properties of CRP and PTX3, emphasizing the differences between the two molecules and the regulatory functions exerted by PTX3 in innate immunity and inflammation.
Project description:Influenza A virions possess two surface glycoproteins-the hemagglutinin (HA) and neuraminidase (NA)-which exert opposite functions. HA attaches virions to cells by binding to terminal sialic acid residues on glycoproteins/glycolipids to initiate the infectious cycle, while NA cleaves terminal sialic acids, releasing virions to complete the infectious cycle. Antibodies specific for HA or NA can protect experimental animals from IAV pathogenesis and drive antigenic variation in their target epitopes that impairs vaccine effectiveness in humans. Here, we review progress in understanding HA/NA co-evolution as each acquires epistatic mutations to restore viral fitness to mutants selected in the other protein by host innate or adaptive immune pressure. We also discuss recent exciting findings that antibodies to HA can function in vivo by blocking NA enzyme activity to prevent nascent virion release and enhance Fc receptor-based activation of innate immune cells.
Project description:Escalating trends of chronic diseases such as type-2 diabetes (T2D) have sparked a renewed interest in complementary and alternative medicine, including herbal products. Morinda citrifolia (noni) has been used for centuries by Pacific Islanders to treat various ailments. Commercial noni fruit juice has been marketed as a dietary supplement since 1996. In 2003, the European Commission approved Tahitian noni juice as a novel food by the Health and Consumer Protection Directorate General. Among noni's several health benefits, others and we have demonstrated the anti-diabetic effects of fermented noni fruit juice in animal models. Unfortunately, noni's exciting journey from Polynesian medicine to the research bench does not reach its final destination of successful clinical outcomes when translated into commercial products. Noni products are perceived to be safe due to their "natural" origin. However, inadequate evidence regarding bioactive compounds, molecular targets, mechanism of action, pharmacokinetics, long-term safety, effective dosages, and/or unanticipated side effects are major roadblocks to successful translation "from bench side to bedside". In this review we summarize the anti-diabetic potential of noni, differences between traditional and modern use of noni, along with beneficial clinical studies of noni products and challenges in clinical translation of noni's health benefits.
Project description:Extracellular adenosine triphosphate (eATP) and its main metabolite adenosine (ADO) constitute an intrinsic part of immunological network in tumor immunity. The concentrations of eATP and ADO in tumor microenvironment (TME) are controlled by ectonucleotidases, such as CD39 and CD73, the major ecto-enzymes expressed on immune cells, endothelial cells and cancer cells. Once accumulated in TME, eATP boosts antitumor immune responses, while ADO attenuates immunity against tumors. eATP and ADO, like yin and yang, represent two opposite aspects from immune-activating to immune-suppressive signals. Here we reviewed the functions of eATP and ADO in tumor immunity and attempt to block eATP hydrolysis, ADO formation and their contradictory effects in tumor models, allowing the induction of effective anti-tumor immune responses in TME. These attempts documented that therapeutic approaches targeting eATP/ADO metabolism and function may be effective methods in cancer therapy.
Project description:BackgroundThe idea of Yin Yang Wu Xing, traditionally adopted and practiced in East-Asian medicine, has not been incorporated into the theoretical framework of modern medicine. It is therefore desired to show that Yin Yang Wu Xing is a manifestation of a higher-level faculty of cooperating system, thus making it suitable for a modern frame of thought.MethodsA higher-level faculty of the cooperating system is formulated in the scheme of Dual Five-Body Coordination. The stability of this scheme is examined mathematically and the feasibility of its physical realization is estimated.ResultsThe Dual Five-Body Coordination scheme, which overlaps substantially with the conceptual structure of Yin Yang Wu Xing, is stable and has survival merit. An imaginable conjecture based on physical reality confirms its physical feasibility.ConclusionThe Dual Five-Body Coordination scheme has potential utilization in various fields including biology and sociology. Once the theoretical framework is solidified, the Dual Five-Body Coordination scheme can be readily applied in practical research in modern medicine.
Project description:Yin Yang 1 (YY1) is a transcription factor with diverse and complex biological functions. YY1 either activates or represses gene transcription, depending on the stimuli received by the cells and its association with other cellular factors. Since its discovery, a biological role for YY1 in tumor development and progression has been suggested because of its regulatory activities toward multiple cancer-related proteins and signaling pathways and its overexpression in most cancers. In this review, we primarily focus on YY1 studies in cancer research, including the regulation of YY1 as a transcription factor, its activities independent of its DNA binding ability, the functions of its associated proteins, and mechanisms regulating YY1 expression and activities. We also discuss the correlation of YY1 expression with clinical outcomes of cancer patients and its target potential in cancer therapy. Although there is not a complete consensus about the role of YY1 in cancers based on its activities of regulating oncogene and tumor suppressor expression, most of the currently available evidence supports a proliferative or oncogenic role of YY1 in tumorigenesis.
Project description:Stimulatory and inhibitory co-receptors play fundamental roles in the regulation of the immune system. We describe a new mouse model of spontaneous autoimmune disease. Activation-induced cytidine deaminase-linked autoimmunity (aida) mice harbor a loss-of-function mutation in the gene encoding lymphocyte activation gene 3 (LAG-3), an inhibitory co-receptor. Although LAG-3 deficiency alone did not induce autoimmunity in nonautoimmune-prone mouse strains, it induced lethal myocarditis in BALB/c mice deficient for the gene encoding the inhibitory co-receptor programmed cell death 1 (PD-1). In addition, LAG-3 deficiency alone accelerated type 1 diabetes mellitus in nonobese diabetic mice. These results demonstrate that LAG-3 acts synergistically with PD-1 and/or other immunoregulatory genes to prevent autoimmunity in mice.
Project description:The tumor microenvironment is a complex structure composed of the extracellular matrix (ECM) and nontumoral cells (notably cancer-associated fibroblasts (CAFs) and immune cells). Collagens are the main components of the ECM and they are extensively remodeled during tumor progression. Some collagens are ligands for the discoidin domain receptor tyrosine kinases, DDR1 and DDR2. DDRs are involved in different stages of tumor development and metastasis formation. In this review, we present the different roles of DDRs in these processes and discuss controversial findings. We conclude by describing emerging DDR inhibitory strategies, which could be used as new alternatives for the treatment of patients.