Generation and multidimensional profiling of a rituximab-resistant ABC-type diffuse large B-cell lymphoma cell line

BACKGROUND: Rituximab resistance remains a major issue in diffuse large B-cell lymphoma (DLBCL), especially the ABC subtype. This study aimed to characterize the transcriptomic and DNA methylation alterations in rituximab‑resistant ABC-type DLBCL cell lines. RESEARCH DESIGN AND METHODS: Rituximab-resistant cell lines were generated from ABC (NU-DUL-1-R) and GCB (SU-DHL-6-R) subtypes using stepwise concentration escalation and were validated by flow cytometry-based complement-dependent cytotoxicity (CDC) and antibody‑dependent cellular cytotoxicity (ADCC) assays, as well as CD20, CD55, and CD59 expression. Transcriptome sequencing and 850K methylation array analysis were performed on parental and resistant NU-DUL-1 cells. Differentially expressed genes and methylated positions were identified, followed by enrichment analyses and integrated analysis. RESULTS: Both resistant cells showed significantly reduced CDC and CD20 downregulation. NU-DUL-1-R cells exhibited impaired ADCC, whereas SU-DHL-6-R cells retained ADCC, but upregulated CD55 and CD59. Integrated analysis identified eight genes (PLD4, MS4A7, FCRL5, PREX1, RASGRP3, ADAM28, RINL, TINAGL1) in NU-DUL-1-R cells with concordant changes in DNA methylation and mRNA expression. Enrichment analysis implicated cAMP, MAPK and PI3K-Akt-mTOR pathways in rituximab-resistance. CONCLUSIONS: This study provides a preliminary characterization of rituximab-resistant ABC-DLBCL cell lines in vitro. The identified subtype-specific mechanisms and candidate genes support further exploration for personalized and epigenetic-targeted therapies.