Epstein−Barr virus-encoded EBNA2 alters immune checkpoint PD-L1 expression by downregulating miR-34a in B-cell lymphomas

• Published in: Leukemia Vol. 33; no. 1; pp. 132 - 147
• Main Authors: Anastasiadou, Eleni, Stroopinsky, Dina, Alimperti, Stella, Jiao, Alan L, Pyzer, Athalia R, Cippitelli, Claudia, Pepe, Giuseppina, Severa, Martina, Rosenblatt, Jacalyn, Etna, Marilena P, Rieger, Simone, Kempkes, Bettina, Coccia, Eliana M, Sui, Shannan J Ho, Chen, Christopher S, Uccini, Stefania, Avigan, David, Faggioni, Alberto, Trivedi, Pankaj, Slack, Frank J
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.01.2019; Nature Publishing Group
• Subjects: 13; 13/109; 13/2; 13/31; 13/51; 13/62; 14; 42; 42/70; 631/67; 631/67/1858; 82; Antibodies; Apoptosis; B-cell lymphoma; B7-H1 Antigen - genetics; B7-H1 Antigen - metabolism; Biomarkers, Tumor - genetics; Biomarkers, Tumor - metabolism; Biomimetics; Burkitt's lymphoma; Cancer; Cancer Research; Carcinogenesis; Cell death; Coding; Combinatorial analysis; Critical Care Medicine; Early B-cell factor; Epstein-Barr virus; Epstein-Barr Virus Infections - complications; Epstein-Barr Virus Infections - virology; Epstein-Barr Virus Nuclear Antigens - genetics; Epstein-Barr Virus Nuclear Antigens - metabolism; Gene Expression Regulation, Neoplastic; Genetic aspects; Genetic regulation; Health aspects; Hematology; Herpesvirus 4, Human - immunology; Humans; Immune checkpoint; Immunogenicity; Immunosurveillance; Immunotherapy; Integrated circuits; Intensive; Internal Medicine; Latency; Lymphocytes B; Lymphoma; Lymphoma, Large B-Cell, Diffuse - genetics; Lymphoma, Large B-Cell, Diffuse - immunology; Lymphoma, Large B-Cell, Diffuse - metabolism; Lymphoma, Large B-Cell, Diffuse - virology; Medicine; Medicine & Public Health; Microfluidics; MicroRNA; MicroRNAs - genetics; miRNA; Oncology; PD-L1 protein; Prognosis; Proteins; Ribonucleic acid; RNA; T-Lymphocytes - immunology; T-Lymphocytes - metabolism; T-Lymphocytes - virology; Transcription; Tumor Cells, Cultured; Tumors; Viral antigens; Viral Proteins - genetics; Viral Proteins - metabolism; Viruses
• ISSN: 0887-6924; 1476-5551; 1476-5551
• DOI: 10.1038/s41375-018-0178-x

Cancer cells subvert host immune surveillance by altering immune checkpoint (IC) proteins. Some Epstein−Barr virus (EBV)-associated tumors have higher Programmed Cell Death Ligand, PD-L1 expression. However, it is not known how EBV alters ICs in the context of its preferred host, the B lymphocyte and in derived lymphomas. Here, we found that latency III-expressing Burkitt lymphoma (BL), diffuse large B-cell lymphomas (DLBCL) or their EBNA2-transfected derivatives express high PD-L1. In a DLBCL model, EBNA2 but not LMP1 is sufficient to induce PD-L1. Latency III-expressing DLBCL biopsies showed high levels of PD-L1. The PD-L1 targeting oncosuppressor microRNA miR-34a was downregulated in EBNA2-transfected lymphoma cells. We identified early B-cell factor 1 (EBF1) as a repressor of miR-34a transcription. Short hairpin RNA (shRNA)-mediated knockdown of EBF1 was sufficient to induce miR-34a transcription, which in turn reduced PD-L1. MiR-34a reconstitution in EBNA2-transfected DLBCL reduced PD-L1 expression and increased its immunogenicity in mixed lymphocyte reactions (MLR) and in three-dimensional biomimetic microfluidic chips. Given the importance of PD-L1 inhibition in immunotherapy and miR-34a dysregulation in cancers, our findings may have important implications for combinatorial immunotherapy, which include IC inhibiting antibodies and miR-34a, for EBV-associated cancers.