Effects of methotrexate and salazosulfapyridine on protein profiles of exosomes derived from a human synovial sarcoma cell line of SW982

Purpose To elucidate effects of salazosulfapyridine (SASP) and methotrexate (MTX), major anti-rheumatic drugs, on exosomes derived from SW982 of a human synovial sarcoma cell line. Experimental design SW982 was treated with SASP and/or MTX under interleukin-1β (IL-1β)-treated or nontreated conditions. Exosomes were isolated from the culture media, and exosomal proteome was analyzed by 2D-DIGE. Protein spots whose intensity was significantly altered by the above treatments were identified by MS. Results Two hundred ninety-four protein spots were detected in the exosome preparations by 2D-DIGE. Compared to the nontreated cells, SASP-, MTX-, and (SASP + MTX)-treated cells displayed 8, 10, and 21 exosomal protein spots with more than ±2.0-fold intensity differences (p < 0.05), respectively. Similarly, the IL-1β-treated cells displayed 58 exosomal protein spots with more than ±1.5-fold intensity differences (p < 0.05). In about half of the 58 spots, the IL-1β-induced intensity changes were suppressed by simultaneous addition of SASP and/or MTX. Most of the identified proteins were immunity- or anti-oxidation-related proteins. Conclusions and clinical relevance The SASP and/or MTX treatments altered the protein profiles of exosomes and suppressed the effects of IL-1β on the exosomal proteome. Exosomes may play roles in the actions of these anti-rheumatic drugs.