ABSTRACT
HLA class I (HLA-I) glycoproteins drive immune responses by presenting antigens to cognate CD8+ T cells. This process is often hijacked by tumors and pathogens for immune evasion. Because options for restoring HLA-I antigen presentation are limited, we aimed to identify druggable HLA-I pathway targets. Using iterative genome-wide screens, we uncovered that the cell surface glycosphingolipid (GSL) repertoire determines effective HLA-I antigen presentation. We show that absence of the protease SPPL3 augmented B3GNT5 enzyme activity, resulting in upregulation of surface neolacto-series GSLs. These GSLs sterically impeded antibody and receptor interactions with HLA-I and diminished CD8+ T cell activation. Furthermore, a disturbed SPPL3-B3GNT5 pathway in glioma correlated with decreased patient survival. We show that the immunomodulatory effect could be reversed through GSL synthesis inhibition using clinically approved drugs. Overall, our study identifies a GSL signature that inhibits immune recognition and represents a potential therapeutic target in cancer, infection, and autoimmunity.
Subject(s)
Aspartic Acid Endopeptidases/metabolism , CD8-Positive T-Lymphocytes/immunology , Glioma/immunology , Glycosphingolipids/metabolism , Glycosyltransferases/metabolism , HLA Antigens/metabolism , Histocompatibility Antigens Class I/metabolism , Immunotherapy/methods , Antigen Presentation , Aspartic Acid Endopeptidases/genetics , Cell Line, Tumor , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , Glioma/mortality , Glycosphingolipids/immunology , HLA Antigens/immunology , Histocompatibility Antigens Class I/immunology , Humans , Lymphocyte Activation , Signal Transduction , Survival Analysis , Tumor EscapeABSTRACT
The morbidity and mortality of lung cancer are increasing. The Corona Virus Disease 2019 (COVID-19) is caused by novel coronavirus 2019-nCoV-2, leading to subsequent pulmonary interstitial fibrosis with chronic inflammatory changes, e.g., inflammatory factors repeatedly continuously stimulating and attacking the alveolar epithelial cells. Meanwhile, 2019-nCoV-2 can activate PI3K/Akt and ERK signaling pathways, which can play the double roles as both anti-inflammatory and carcinogenic factors. Moreover, hypoxemia may be developed, resulting in the up-regulation of HIF-1 α expression, which can be involved in the occurrence, angiogenesis, invasion and metastasis of lung cancer. Additionally, the immune system in 2019-nCoV-2 infected cases can be suppressed to cause tumor immune evasion. Therefore, we speculate that COVID-19 may be a risk factor of secondary lung cancer.