Western blot analysis confirms changes in protein levels after MUC1 small interfering RNA (siRNA). (a) Whole cell lysates were analyzed for the following proteins: MUC1 extracellular subunit (MUC1-EX), c-Myc, total and active MAPK and ERK kinase (MEK)1/2 (MEK1/2, pMEK1/2), total and active extracellular signal regulated kinase (ERK)1/2 (ERK1/2, dpERK1/2), total and active AKT (AKT, pAKT), and tubulin as a loading control. Densitometry is shown for each blot, based on three independent measurements per band, normalized to tubulin; results are shown relative to luciferase siRNA (siLuc) for each cell line. Optimal exposures for comparing luciferase siRNA and MUC1 siRNA-treated cells from the same parental line are shown. (b) Lysates from epidermal growth factor (EGF)-stimulated MDA-MB-468 cells were blotted for MEK1/2, pMEK1/2, MUC1-EX, and actin (for loading).