Abstract 306: Analysis of differentially expressed exosomal genes from ibrutinib resistant diffuse large B cell lymphoma

Abstract

Abstract Diffuse large B cell lymphoma (DLBCL) is the most common subtype of non-Hodgkin lymphoma (NHL) and approximately 30% of the patients develop relapsed/refractory disease that becomes a major cause of mortality and morbidity. Selective pressure provided by chemotherapy causes aberrant gene expression and selection of pre-existing population of chemo-resistant cells. These chemo-resistant cells can also transmit chemo-resistance to chemo-sensitive cells through exosomal transfer of molecules (miRNA, mRNA and proteins). In this study, we have analysed differentially expressed mRNA and miRNA from syngeneic ibrutinib (an irreversible BTK inhibitor, FDA approved) resistant DLBCL cells and from their isolated exosomes. Five DLBCL-GCB and five ABC subtype were analysed for their sensitivity with ibrutinib. We found three ABC subtype and one GCB subtype (OCL-LY1) were sensitive to ibrutinib. We have generated syngeneic ibrutinib drug resistant model from sensitive cells (at least 10 fold increase in IC50 value) by continuous culturing them in the presence of ibrutinib with gradual increase in drug concentration in each passage. Ibrutinib sensitive DLBCL cells when cultured with the syngeneic resistant cells in transwell apparatus, acquired resistance to ibrutinib. We also analysed the sensitivity of ibrutinib resistant cells with other conventional drugs for non-Hodgkin lymphomas. We further tested the expression of drug resistant genes in syngeneic resistant cells by real time PCR analysis. Later, we isolated the total RNA and miRNA species from DLBCL ibrutinib sensitive, their syngeneic resistant cells and from respective exosomes and analysed for differential expression by micro array analyses. Thus in conclusion, our study demonstrates that chemo-resistance can be transferred from resistant cells to sensitive cells via exosomal horizontal transmission of miRNA and mRNA in diffuse large B cell lymphoma cells. Moreover, our study identified potential targets that can be used to overcome chemo-resistance in diffuse large B cell lymphoma. Citation Format: Neeraj Jain, Lalit Sehgal, Tamer Khashab, Felipe Samaniego. Analysis of differentially expressed exosomal genes from ibrutinib resistant diffuse large B cell lymphoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 306.