Fig. 6. The regulatory effect of rBM on ER levels is independent of cell shape changes. (A) Primary cells (a) and Scp2 cells (b) form typical flattened monolayers on plastic. Morphological change (cell rounding and aggregation) can be induced by the non-adherent substratum polyHEMA in primary cells (c) and in Scp2 cells (d). The addition of rBM on polyHEMA did not affect this cell rounding (e,f). Bar, 100 µm. (B) The densitometric analysis of ER protein levels determined by western blot in primary mammary epithelial cells at days 2 or 6 after isolation (a) and in Scp2 cells at day 3 in culture (b) shows that addition of rBM to pre-rounded cells was necessary to upregulate ER over basal levels detected on plastic. n=3; *P<0.05.