PP1 or AZD0530 tyrosine kinase inhibitors had no effect on ERα protein degradation in MCF-7 cells.

<p>In panels (<b>A</b>) and (<b>B</b>), ERα protein expression after 6-hour exposure to 100 nM fulvestrant in the presence of PP1 or AZD0530 was determined by Western blotting (A) and ELISA (B, mean±SEM of three or more independent experiments. Asterisks indicate statistical significance, p<0.05, to fulvestrant-only group). In panels (<b>C</b>) and (<b>D</b>), fulvestrant concentration was reduced as indicated, and ERα protein expression after 6-hour exposure in the presence of PP1 or AZD0530 was determined by Western blotting (<b>C</b>). Panel (<b>D</b>) shows a typical densitometric quantitation of the ERα protein band. Three independently performed experiments did not show statistically significant effects of PP1 or AZD0530.</p>