Figure 3. Down-regulation of Estrogen Receptor by CM from HS5 and hFOB stromal cells.
A. Immunofluorescent stain of MCF7 cells exposed to control medium or to HS5-CM. ER immunostaining (above); Hoechst stain shown below. B. Down-regulation of ER in MCF7 by HS5-CM and hFOB CM and not by KM101, or HS27A. Two exposures of ER immunoblotting shown. Cells were incubated with 30% CM for 16 hours before harvest. CM’s and medium controls (1, DMEM, 10% serum; 2, DMEM/F12 10% serum) were added to 30% v/v. Actin loading control shown for each of two parallel gels. C. Vehicle control (v/v, DMSO) and p38 inhibitors at 10uM did not prevent ER downregulation by HS5 and hFOB CM. 20 hour incubation of MCF7 with CM. D. PBS control or 10μg/ml of exosomes from HS5 and from (control) KM101 had no effect on ER expression.