Figure 4. Stable over-expression of MRP4 does not enhance PGE2 export from MCF7 cells.

A. Vector-expressing control cells (MCF7-Vec) or MRP4-expressing cells (MCF7-MRP4-2, MCF7-MRP4-3) were stimulated with 10 μg/mL LPS for 24 hours. Total protein lysate was collected for western blot to determine relative levels of MRP4 and COX-2 expression. β-actin was used as a loading control. B. Conditioned media was collected and assayed for PGE₂. PGE₂ is expressed as mean ± SEM pg/μg protein from triplicate determinations. Western blot lanes are vertically aligned with corresponding PGE₂ levels.