The effect of proteasome inhibitor (AM114) on apoptosis in IL-1b-treated peripheral blood macrophage cultured cells from rheumatoid arthritis patients

Abstract Objectives Monocytes/macrophages play a central role in the innate immune response and inflammatory process. The induction of apoptosis by AM114 has been studied in many cancer cell lines but not in rheumatoid arthritis (RA) relevant cell types. Therefore, the objective of the study was to explore the effect of proteasome inhibitor (PI) AM114 on apoptosis in IL-1β-treated peripheral blood macrophage cultured cells (PBMCC) from RA patients in comparison with aspirin. Methods The efficacy of AM114, with or without IL-1β-treated macrophages, was assessed by comparing with aspirin-treated cells. The induction of apoptosis was determined in IL-1β, treated (10 ng/mL) for 24 h, macrophages isolated from peripheral blood of RA patients. The cell viability was determined by MTT assay. The cell morphological assessment of apoptosis was determined using acridine orange ethidium bromide (AO/EtBr), Hoechst 33342, and rhodamine 123 assays. The activity of caspase-3 was determined by spectrofluorimetry in IL-1β-treated PBMCC exposed to AM114 and aspirin. Student's t -test was used to compare the different groups. Results In the present study, the IC50 concentrations for induction of apoptosis by AM114 and aspirin were found to be at 0.88 μM/mL and 1120 μM/mL, respectively. The presence of apoptotic cells was detected by the presence of condensed form of nuclei, apoptotic bodies, cytoplasmic blebbing, and change in mitochondrial membrane potential. The caspase-3 activity was increased 0.7-fold in AM114 with IL-1β-treated cells than the unstimulated PI-treated cells. An increase of 0.5-fold in caspase-3 activity was observed in AM114-stimulated cells in comparison with aspirin-stimulated cells. Conclusions The AM114 is efficacious than aspirin-treated IL-1β-treated PBMCC from RA patients by inducing apoptosis and increase in caspase-3 activity.