Figure 4.

SIN-1 induces a de novo synthesis of hypoglycosylated COX-2. HUVEC were treated with SIN-1 or IL-1α, either alone or in combination for 18 h. (A) Tran [³⁵S]-label was added 6 or 12 h after the beginning of incubation. At the end of incubation, COX-2 was immunoprecipitated. (B) Cells were treated with the stimuli for 18 h in the presence of cycloheximide (CHX). (C) CHX was added to HUVEC incubated with SIN-1 or SIN-1 + IL-1α, either alone or in combination, at different time after the start of incubation, as indicated. COX-2 expression was evaluated by Western blot analysis. β-actin was used as a control of protein loading. Samples with CHX added for 12 and 14 h-treatment were run on separate parallel gels. For SIN-1-treated cells, the samples for the cells treated with CHX added for 12 and 14-h were run on the same gel but were non-contiguous. Results are representative of 3 independent experiments.