Fig. 4.

Effects of mucin 1 (MUC1) on apoptosis and proliferation in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLSs). Silencing efficiency of MUC1-targeting small interfering RNA (siRNA) was measured by a) quantitative real-time polymerase chain reaction (qRT-PCR) (n = 3) and b) western blot (WB). Three siRNAs targeting MUC1 were designed and named as siMUC1-1, siMUC1-2, and siMUC1-3, respectively. Effects of c) MUC1 silencing (n = 3) and d) MUC1 inhibitor GO-203 treatment (5 μM, 48 hours) (n = 6) on cell apoptosis of RA FLSs were measured by flow cytometry following staining with FITC-conjugated Annexin V/propidium iodide (PI). Early apoptotic cells defined as PI negative and Annexin V positive cells were quantified. e) After transfection with MUC1-targeting siRNA for the indicated time, cell viability was measured by Cell Counting Kit-8 (CCK-8) assay; n = 5 at different timepoints. f) RA FLSs were treated with different concentrations of GO-203 for the indicated time and cell viability was measured; n = 3 at different timepoints. Ctr, control; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; mRNA, messenger RNA; NC, negative control.