Molecular dynamics of the immune checkpoint Programmed Cell Death Protein I, PD-1: Conformational changes of the BC-loop upon binding of the ligand PD-L1 and the monoclonal antibody nivolumab

Author(s):  
Bernhard Roither ◽  
Chris Oostenbrink ◽  
Wolfgang Schreiner
2020 ◽  
Vol 21 (S17) ◽  
Author(s):  
Bernhard Roither ◽  
Chris Oostenbrink ◽  
Wolfgang Schreiner

Abstract Background The immune checkpoint receptor programmed cell death protein I (PD-1) has been identified as a key target in immunotherapy. PD-1 reduces the risk of autoimmunity by inducing apoptosis in antigen-specific T cells upon interaction with programmed cell death protein ligand I (PD-L1). Various cancer types overexpress PD-L1 to evade the immune system by inducing apoptosis in tumor-specific CD8+ T cells. The clinically used blocking antibody nivolumab binds to PD-1 and inhibits the immunosuppressive interaction with PD-L1. Even though PD-1 is already used as a drug target, the exact mechanism of the receptor is still a matter of debate. For instance, it is hypothesized that the signal transduction is based on an active conformation of PD-1. Results Here we present the results of the first molecular dynamics simulations of PD-1 with a complete extracellular domain with a focus on the role of the BC-loop of PD-1 upon binding PD-L1 or nivolumab. We could demonstrate that the BC-loop can form three conformations. Nivolumab binds to the BC-loop according to the conformational selection model whereas PD-L1 induces allosterically a conformational change of the BC-loop. Conclusion Due to the structural differences of the BC-loop, a signal transduction based on active conformation cannot be ruled out. These findings will have an impact on drug design and will help to refine immunotherapy blocking antibodies.


2021 ◽  
Vol 12 ◽  
Author(s):  
Wang Xie ◽  
NaNa Hu ◽  
LeJie Cao

Immune checkpoint inhibitors (ICIs), including antibodies targeting programmed cell death protein-1 (PD-1) and programmed cell death ligand-1 (PD-L1), are being extensively used on advanced human malignancies therapy. The treatment with ICIs have acquired durable tumor inhibition and changed the treatment landscape in lung cancer. Immune-related adverse events including pneumonitis and thyroiditis have been well described, but less frequent events, such as ICIs-induced thrombocytopenia, are now emerging and may sometimes be severe or fatal. Since early detection and prompt intervention are crucial to prevent fatal consequences, it is of outmost importance that medical staff is aware of these potential toxicities and learn to recognize and treat them adequately. This review focuses on the epidemiology, clinical presentation, mechanisms, and clinical management of ICIs-induced thrombocytopenia in patients with lung cancer. We also present a patient with advanced lung adenocarcinoma who received the PD-L1 inhibitor atezolizumab and eventually developed severe thrombocytopenia. The case indirectly suggests that cytokine changes might contribute to immune dysregulation in ICIs-induced thrombocytopenia.


2020 ◽  
Vol 21 (15) ◽  
pp. 5456 ◽  
Author(s):  
Ayumi Kuzume ◽  
SungGi Chi ◽  
Nobuhiko Yamauchi ◽  
Yosuke Minami

Tumor cells use immune-checkpoint pathways to evade the host immune system and suppress immune cell function. These cells express programmed cell-death protein 1 ligand 1 (PD-L1)/PD-L2, which bind to the programmed cell-death protein 1 (PD-1) present on cytotoxic T cells, trigger inhibitory signaling, and reduce cytotoxicity and T-cell exhaustion. Immune-checkpoint blockade can inhibit this signal and may serve as an effective therapeutic strategy in patients with solid tumors. Several trials have been conducted on immune-checkpoint inhibitor therapy in patients with malignant lymphoma and their efficacy has been reported. For example, in Hodgkin lymphoma, immune-checkpoint blockade has resulted in response rates of 65% to 75%. However, in non-Hodgkin lymphoma, the response rate to immune-checkpoint blockade was lower. In this review, we evaluate the biology of immune-checkpoint inhibition and the current data on its efficacy in malignant lymphoma, and identify the cases in which the treatment was more effective.


2018 ◽  
Vol 71 (8) ◽  
pp. 665-671 ◽  
Author(s):  
Dipti M Karamchandani ◽  
Runjan Chetty

Immune checkpoint inhibitors (CPIs) are a relatively new class of ‘miracle’ dugs that have revolutionised the treatment and prognosis of some advanced-stage malignancies, and have increased the survival rates significantly. This class of drugs includes cytotoxic T lymphocyte antigen-4 inhibitors such as ipilimumab; programmed cell death protein-1 inhibitors such as nivolumab, pembrolizumab and avelumab; and programmed cell death protein ligand-1 inhibitors such as atezolizumab. These drugs stimulate the immune system by blocking the coinhibitory receptors on the T cells and lead to antitumoural response. However, a flip side of these novel drugs is immune-related adverse events (irAEs), secondary to immune-mediated process due to disrupted self-tolerance. The irAEs in the gastrointestinal (GI) tract/liver may result in diarrhoea, colitis or hepatitis. An accurate diagnosis of CPI-induced colitis and/or hepatitis is essential for optimal patient management. As we anticipate greater use of these drugs in the future given the significant clinical response, pathologists need to be aware of the spectrum of histological findings that may be encountered in GI and/or liver biopsies received from these patients, as well as differentiate them from its histopathological mimics. This present review discusses the clinical features, detailed histopathological features, management and the differential diagnosis of the luminal GI and hepatic irAEs that may be encountered secondary to CPI therapy.


2017 ◽  
Vol 312 (5) ◽  
pp. H1052-H1059 ◽  
Author(s):  
Ryu Watanabe ◽  
Hui Zhang ◽  
Gerald Berry ◽  
Jörg J. Goronzy ◽  
Cornelia M. Weyand

Giant cell arteritis (GCA) is a granulomatous vasculitis of the aorta and its medium-sized branch vessels. CD4 T cells, macrophages, and dendritic cells (DCs) build granulomatous infiltrates that injure the vessel wall and elicit a maladaptive response to injury. Pathological consequences include fragmentation of elastic membranes, destruction of the medial layer, microvascular neoangiogenesis, massive outgrowth of myofibroblasts, and lumen-occlusive intimal hyperplasia. Antigens have been suspected to drive the local activation of vasculitogenic CD4 T cells, but recent data have suggested a more generalized defect in the threshold setting of such T cells, rendering them hyperreactive. Under physiological conditions, immune checkpoints provide negative signals to curb T cell activation and prevent inflammation-associated tissue destruction. This protective mechanism is disrupted in GCA. Vessel wall DCs fail to express the immunoinhibitory ligand programmed cell death ligand-1, leaving lesional T cells unchecked. Consequently, programmed cell death protein-1-positive CD4 T cells can enter the immunoprivileged vessel wall, where they produce a broad spectrum of inflammatory cytokines (interferon-γ, IL-17, and IL-21) and have a direct role in driving intimal hyperplasia and intramural neoangiogenesis. The deficiency of the programmed cell death protein-1 immune checkpoint in GCA, promoting unopposed T cell immunity, contrasts with checkpoint hyperactivity in cancer patients in whom excessive programmed cell death ligand-1 expression paralyzes the function of antitumor T cells. Excessive checkpoint activity is the principle underlying cancer-immune evasion and is therapeutically targeted by immunotherapy with checkpoint inhibitors. Such checkpoint inhibitors, which unleash anticancer T cells and induce immune-related toxicity, may lead to drug-induced vasculitis.


2017 ◽  
Vol 103 (2) ◽  
pp. 365-369 ◽  
Author(s):  
Chen Zhao ◽  
Sri Harsha Tella ◽  
Jaydira Del Rivero ◽  
Anuhya Kommalapati ◽  
Ifechukwude Ebenuwa ◽  
...  

Abstract Context Immune checkpoint inhibitors, including anti–programmed cell death protein 1 (PD-1), anti–programmed cell death protein ligand 1 (PD-L1), and anti–cytotoxic T-lymphocyte antigen 4 (anti-CTLA4) monoclonal antibodies, have been widely used in cancer treatment. They are known to cause immune-related adverse events (irAEs), which resemble autoimmune diseases. Anterior pituitary hypophysitis with secondary hypopituitarism is a frequently reported irAE, especially in patients receiving anti–CTLA4 treatment. In contrast, posterior pituitary involvement, such as central diabetes insipidus (DI), is relatively rare and is unreported in patients undergoing PD-1/PD-L1 blockade. Case Description We describe a case of a 73-year-old man with Merkel cell carcinoma who received the anti–PD-L1 monoclonal antibody avelumab and achieved partial response. The patient developed nocturia, polydipsia, and polyuria 3 months after starting avelumab. Further laboratory testing revealed central DI. Avelumab was held and he received desmopressin for the management of central DI. Within 6 weeks after discontinuation of avelumab, the patient’s symptoms resolved and he was eventually taken off desmopressin. The patient remained off avelumab and there were no signs or symptoms of DI 2 months after the discontinuation of desmopressin. Conclusion To our knowledge, this is the first report of central DI associated with anti–PD-L1 immunotherapy. The patient’s endocrinopathy was successfully managed by holding treatment with the immune checkpoint inhibitor. This case highlights the importance of early screening and appropriate management of hormonal irAEs in subjects undergoing treatment with immune checkpoint inhibitors to minimize morbidity and mortality.


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