Dynamic Interplay of miR-155-5p Transfer in the Mechanisms Underlying Ibrutinib Resistance in DLBCL through Extracellular Vesicles

Abstract

Ibrutinib, a Bruton Tyrosine Kinase (BTK) inhibitor, has exhibited efficacy in various B-cell lymphoid malignancies. However, prolonged usage may lead to resistance, impacting treatment outcomes. The oncogenic microRNA, miR-155-5p is related with poor prognosis in B-cell lymphomas, prompting our investigation into the mechanism of acquired ibrutinib resistance in B-cell lymphoma cells. To generate ibrutinib-resistant OCI-Ly1 cells (OCI-Ly1-IbtR), continuous exposure to 1µM and 2µM of ibrutinib was employed. microRNA profiling of OCI-Ly1-IbtR was conducted, and exosomes were isolated using ultracentrifugation. Comparative studies of microRNA levels in cells and exosomes, and targets of up-regulated microRNAs in OCI-Ly1-IbtR were explored. Target validation involved transfection of candidate microRNA, and co-culture experiments utilized OCI-Ly1 with exosomes from OCI-Ly1-IbtR. Elevated miR-155-5p levels were observed in OCI-Ly1-IbtR and exosomes from OCI-Ly1-IbtR, correlating with AKT and NF-κB activation. MiR-155-5p transfection induced AKT/NF-κB pathway activation in OCI-Ly1, resulting in ibrutinib resistance, enhanced colony formation and sustained BTK activity. Primary cell lines from ibrutinib-refractory B-cell lymphoma patients exhibited similar signaling protein activation. Target evaluation identified KDM5B and DEPTOR as miR-155-5p targets, confirmed by downregulation after transfection. KDM5B and DEPTOR enrichment in Ago2 during ibrutinib resistance and miR-155-5p transfection was observed. Co-culture experiments demonstrated exosome-mediated miR-155-5p transfer, inducing ibrutinib resistance and KDM5B/DEPTOR downregulation in OCI-Ly1. Our findings suggest that miR-155-5p overexpression is associated with AKT and NF-κB pathway activation in ibrutinib-resistant cells, proposing a potential role for acquired miR-155-5p upregulation in B-cell lymphoma ibrutinib resistance.