Characterization of extracellular vesicles in AIDS-associated non-Hodgkin lymphoma.

Abstract

Abstract Even with the use of anti-retroviral therapy, HIV +subjects develop non-Hodgkin lymphoma (NHL) at a higher frequency than uninfected subjects. Extracellular vesicles (EVs) secreted by cells may contain immunomodulatory molecules; for example, tumor cells can secrete EVs containing bioactive PD-L1 that can inhibit anti-tumor responses. We have shown EVs bearing PD-L1, TNF-RII or IL-6Rα can be biomarkers of NHL risk. Here we aim to characterize EVs isolated from EBV +and EBV −lymphoma cell lines to define their involvement in lymphomagenesis and identify more EV-associated biomarkers for NHL risk (like immune checkpoint molecules CD80, CD86, CD28). EVs were isolated from AIDS-NHL and NHL cell lines using a total exosome isolation kit and analyzed by Western blot. A subset of these were also analyzed by proteomics using Metascape, Reactome, and R. EVs were also isolated from archived serum of HIV +individuals before NHL onset (n = 51) and matched HIV +controls (n = 53) from participants of the MACS/WIHS Combined Cohort study, with a total exosome isolation kit and characterized by Western blot. EV-specific markers were detected in EVs isolated from cell lines and serum. EVs isolated from EBV +cell lines largely expressed LMP1, an EBV CD40 homolog that induces EBV-driven B cell transformation. In EVs isolated from serum, levels of CD80, CD86, or CD28 were comparable between pre-NHL samples and matched controls, though control samples tended to have greater CD80 and CD86 expression. Our findings shed light on the EV marker expression profiles of AIDS-NHL and NHL cell lines and show LMP1 expression in EBV +cell lines. Additionally, this research provides initial insight into the complex composition of EVs and their role in lymphomagenesis. Supported by grants from NIH (R01CA228157, P30CA016042-S, R01CA228157S)