Anti CD20 increases PD-L1 protein expression in a cell line of primary mediastinal B cell lymphoma through immunogenetic and micro RNA signaling

Cell lines of mediastinal lymphomas, one each of primary mediastinal (thymic) large B cell lymphoma (PMBL), classic Hodgkin lymphoma (CHL), B-cell lymphoma, unclassifiable, with features intermediate between diffuse large B-cell lymphoma and CHL, and T-cell lymphoma were treated with rituximab (RmAb), brentuximab vedotin (BV), ibrutinib (IBR), prednisone (PRED) or untreated (UT) for 48 hours. Flow cytometry for PD-L1 protein was performed, and differential expression (DE) analysis of mRNA and miRNA performed by RNAseq. B-cell lines exhibited 2- fold increase in PD-L1 protein (p<.05) with RmAb compared to UT. Others showed no effect of RmAb, however, the T-cell line showed 2-fold increase on treatment with BV (P<.05). DE performed by limma showed no genomic level changes. ANOVA analysis of PMBL treated with RmAb, however, showed physiologic level DE involving >3000 genes involving multiple pathways associated with cell death and survival, protein degradation, mRNA translation, mRNA degradation, immunologic functions, and PD-1/PD-L1 immunotherapy. In the B cell lines, DE of CD274 (PD-L1) was decreased or not significant. MiRNA DE showed upregulation of 7 miRNAs, including miR-155-5p. Overall design: Multiple cell lines were treated with rituximab (RmAb), brentuximab vedotin (BV), ibrutinib (IBR), and prednisone(PRED) prior to differential expression (DE) analysis of mRNA and miRNA performed by bulk RNAseq.