Effect of dehydroxymethylepoxyquinomicin on human fibroblast-like synovial cells. Effect of dehydroxymethylepoxyquinomicin (DHMEQ) on expression of receptor activator of NF-κB ligand (RANKL) and of macrophage colony-stimulating factor (M-CSF) by fibroblast-like synovial cells obtained from patients with rheumatoid arthritis (RA-FLS). The RA-FLS were incubated with DHMEQ, with vehicle (dimethyl sulfoxide (DMSO)), or with PBS for 24 hours. (a) Cell lysates were analyzed by western blotting with anti-RANKL or with anti-β-actin monoclonal antibody. Representative data of similar results obtained using cell lines from two patients with RA are shown. (b) Concentration of M-CSF in the culture supernatant measured by ELISA; results expressed as relative values compared with PBS. Data are the mean ± standard error of the mean of independent experiments carried out in triplicate using cell lines obtained from six patients with RA, and were compared by Student's t test. *P < 0.05.