Project description:Immune checkpoint inhibition has been shown to successfully reactivate T cell responses directed against tumor-associated antigens, resulting in significantly prolonged overall survival in patients with various types of solid tumors. Among them, cytotoxic T-lymphocyte protein 4 (CTLA-4) and programmed cell death protein 1 (PD-1) play key roles in tumor immune escape and are well-established targets of cancer immunotherapy. However, the low response rate PD-1 and CTLA-4 is a limitation and a challenge. Hence, studies have focused on investigating the tumor microenvironment for alternative therapeutic targets. Lymphocyte activation gene 3 protein (LAG-3) negatively regulates T lymphocytes by binding to the extracellular domain of the ligand, thus avoiding autoimmunity caused by T cell overactivation. LAG-3 is an important immune checkpoint in vivo and plays a balanced regulatory role in the human immune system. LAG-3 is now regarded as a new generation of immunotherapy targets. The present review describes the research progress of LAG-3 to provide reference for further investigation of LAG-3. The immune checkpoint of LAG-3 plays a crucial role in cancer development and may be used in future clinical practice of cancer therapy.
Project description:One of the most important steps forward in the management of cancer was the discovery of immunotherapy. It has become an essential pillar in the treatment paradigm of cancer patients. Unfortunately, despite the various options presented with immune checkpoint inhibitors (ICIs), the benefit is still limited to select patients and the vast majority of these patients gain either minimal benefit or eventually progress, leaving an unmet need for the development of novel therapeutic agents and strategies. Lymphocyte activation gene-3 (LAG-3), an immune checkpoint receptor protein, is a molecule found on the surface of activated T-cells. It plays a major role in negatively regulating T-cell function thereby providing tumors with an immune escape in the tumor microenvironment (TME). Given its importance in regulating the immune system, LAG-3 has been considered as a promising target in oncology and precision medicine. To date, two LAG-3-directed agents (eftilagimod alpha and relatlimab) have been approved in combination with programmed death-1 (PD-1) inhibitors in the setting of advanced solid tumors. In this review, we discuss the structure of LAG-3, its mechanism of action, and its interaction with its ligands. We also shed light on the emerging treatments targeting LAG-3 for the treatment of solid tumors.
Project description:Cancer immunotherapy and tumor microenvironment have been at the forefront of research over the past decades. Targeting immune checkpoints especially programmed death 1 (PD-1)/programmed death ligand 1 (PD-L1) has made a breakthrough in treating advanced malignancies. However, the low response rate brings a daunting challenge, changing the focus to dig deeply into the tumor microenvironment for alternative therapeutic targets. Strikingly, the inhibitory immune checkpoint lymphocyte activation gene-3 (LAG-3) holds considerable potential. LAG-3 suppresses T cells activation and cytokines secretion, thereby ensuring immune homeostasis. It exerts differential inhibitory impacts on various types of lymphocytes and shows a remarkable synergy with PD-1 to inhibit immune responses. Targeting LAG-3 immunotherapy is moving forward in active clinical trials, and combination immunotherapy of anti-LAG-3 and anti-PD-1 has shown exciting efficacy in fighting PD-1 resistance. Herein, we shed light on the significance of LAG-3 in the tumor microenvironment, highlight its role to regulate different lymphocytes, interplay with other immune checkpoints especially PD-1, and emphasize new advances in LAG-3-targeted immunotherapy.
Project description:Lymphocyte activation gene (Lag)-3 is an inhibitory co-receptor and target of immune checkpoint inhibitor (ICI) therapy for cancer. The dynamic behavior of Lag-3 was analyzed at the immune synapse upon T-cell activation to elucidate the Lag-3 inhibitory mechanism. Lag-3 formed clusters and co-localized with T-cell receptor microcluster (TCR-MC) upon T-cell activation similar to PD-1. Lag-3 blocking antibodies (Abs) inhibited the co-localization between Lag-3 and TCR-MC without inhibiting Lag-3 cluster formation. Lag-3 also inhibited MHC-II-independent stimulation and Lag-3 Ab, which did not block MHC-II binding could still block Lag-3's inhibitory function, suggesting that the Lag-3 Ab blocks the Lag-3 inhibitory signal by dissociating the co-assembly of TCR-MC and Lag-3 clusters. Consistent with the combination benefit of PD-1 and Lag-3 Abs to augment T-cell responses, bispecific Lag-3/PD-1 antagonists effectively inhibited both cluster formation and co-localization of PD-1 and Lag-3 with TCR-MC. Therefore, Lag-3 inhibits T-cell activation at TCR-MC, and the target of Lag-3 ICI is to dissociate the co-localization of Lag-3 with TCR-MC.
Project description:LAG-3, a type of immune checkpoint receptor protein belonging to the immunoglobulin superfamily, is confirmed to be expressed on activated immune cells, mainly including activated T cells. LAG-3 can negatively regulate the function of T cells, exerting important effects on maintaining the homeostasis of the immune system under normal physiological conditions and promoting tumor cells immune escape in the tumor microenvironment. Given its important biological roles, LAG-3 has been regarded as a promising target for cancer immunotherapy. To date, many LAG-3 inhibitors have been reported, which can be divided into monoclonal antibody, double antibody, and small molecule drug, some of which have entered the clinical research stage. LAG-3 inhibitors can negatively regulate and suppress T cell proliferation and activation through combination with MHC II ligand. Besides, LAG-3 inhibitors can also affect T cell function via binding to Galectin-3 and LSECtin. In addition, LAG-3 inhibitors can prevent the FGL1-LAG-3 interaction, thereby enhancing the human body's antitumor immune effect. In this review, we will describe the function of LAG-3 and summarize the latest LAG-3 inhibitors in the clinic for cancer therapy.
Project description:Immune checkpoint blocking antibodies are a cornerstone in cancer treatment; however, they benefit only a subset of patients and biomarkers to guide immune checkpoint blockade (ICB) treatment choices are lacking. We designed this study to identify blood-based correlates of clinical outcome in ICB-treated patients. We performed immune profiling of 188 ICB-treated patients with melanoma using multiparametric flow cytometry to characterize immune cells in pretreatment peripheral blood. A supervised statistical learning approach was applied to a discovery cohort to classify phenotypes and determine their association with survival and treatment response. We identified three distinct immune phenotypes (immunotypes), defined in part by the presence of a LAG-3+CD8+ T cell population. Patients with melanoma with a LAG+ immunotype had poorer outcomes after ICB with a median survival of 22.2 months compared to 75.8 months for those with the LAG- immunotype (P = 0.031). An independent cohort of 94 ICB-treated patients with urothelial carcinoma was used for validation where LAG+ immunotype was significantly associated with response (P = 0.007), survival (P < 0.001), and progression-free survival (P = 0.004). Multivariate Cox regression and stratified analyses further showed that the LAG+ immunotype was an independent marker of outcome when compared to known clinical prognostic markers and previously described markers for the clinical activity of ICB, PD-L1, and tumor mutation burden. The pretreatment peripheral blood LAG+ immunotype detects patients who are less likely to benefit from ICB and suggests a strategy for identifying actionable immune targets for further investigation.
Project description:Immune checkpoint inhibition (ICI) is a promising cancer therapy, which has progressed rapidly from a preclinical concept to clinical implementation. Commonly considered targets in ICI are CTLA-4, PD-1/PD-L1, and LAG-3, and the list grows. As ICI is generally only beneficial for a subset of patients, there is a need to select patients that are eligible for therapy as well as to monitor therapy response. There is growing interest to do this noninvasively, by molecular imaging with target-specific tracers. To this day, noninvasive imaging has focused on CTLA-4 and PD-1/PD-L1, while there is no noninvasive tool available to accurately assess LAG-3 expression in vivo. In this proof-of-concept study, we developed nanobodies, the smallest functional fragments from camelid heavy chain-only antibodies, to noninvasively evaluate mouse LAG-3 expression using single photon emission computed tomography (SPECT)/CT imaging. The in vitro characterization of 114 nanobodies led to the selection of nine nanobodies binding to mouse LAG-3. The injection of 99mTechnetium-labeled nanobodies in healthy mice showed specific uptake in immune peripheral organs like the spleen and lymph nodes, which was not observed in LAG-3 gene knock-out mice. Moreover, nanobody uptake could be visualized using SPECT/CT and correlated to the presence of LAG-3 as assessed in flow cytometry and immunohistochemistry. SPECT/CT scans of tumor bearing mice further confirmed the diagnostic potential of the nanobodies. These findings substantiate the approach to use nanobodies as a tool to image inhibitory immune checkpoints in the tumor environment.
Project description:Immune checkpoint inhibitor (ICI)-related myocarditis has been reported to appear in the early phase after ICI initiation. Herein, we report the case of a 78-year-old man with non-small cell lung cancer. Pembrolizumab was introduced as first-line therapy. After 9 months, second-line therapy, including bevacizumab, was initiated. After another 7 months, echocardiography showed diffuse left ventricular dysfunction. Based on the histopathologic examination of the myocardium, the patient was diagnosed with ICI-related myocarditis. Initiation of prednisolone therapy improved cardiac function. This case of late-onset ICI-related myocarditis illustrates that endomyocardial biopsy can be useful in the differential diagnosis of cancer-related left ventricular dysfunction.
Project description:BackgroundAntibodies that target immune checkpoints such as cytotoxic T lymphocyte antigen 4 (CTLA-4), programmed cell death protein/ligand 1 (PD-1/PD-L1) are approved for treatment of multiple cancer types. Chemotherapy is often administered with immune checkpoint blockade (ICB) therapies that target CTLA-4 and/or PD-(L)1. ICB targeting other immune checkpoints such as lymphocyte activating gene-3 (LAG-3) has the potential to improve antitumor responses when combined with chemotherapy. Response to anti-PD-1 ICB is dependent on progenitor exhausted CD8+ T cells (TPEX) in the tumor, but it is unclear how chemotherapy alters TPEX proportions and phenotype.MethodsHere we investigated whether sequential chemotherapy altered TPEX frequency and immune checkpoint expression in multiple murine tumor models.ResultsTwo doses of two different anti-metabolite chemotherapies increased tumor infiltrating CD4+, and CD8+ TPEX expressing LAG-3 in multiple mouse models, which was not restricted to tumor antigen specific CD8+ T cells. To determine if LAG-3+tumor infiltrating lymphocytes (TILs) could be targeted to improve tumor control, we administered anti-LAG-3 and anti-PD-1 ICB after two doses of chemotherapy and found combination therapy generated robust antitumor responses compared with each agent alone. Both anti-LAG-3 and anti-PD-1 ICB with chemotherapy were required for the complete tumor regression observed.ConclusionsChanges in immune checkpoint expression on TILs during chemotherapy administration informs selection of ICB therapies to combine with.