Figure 4.

A, Levels of endogenous PRLr in T47D-derived cells that harbor shCON or shRNA against PRLr (shPRLr) were determined by immunoprecipitation (IP)-immunoblotting (IB) as described in details in Ref. 12. B, Pyruvate kinase activity was measured in the lysates from T47D-derived cells that harbor shCON or shRNA against PRLr (shPRLr). Cells (that were described in details in Ref. 12) were left untreated (gray bars) or treated with PRL (100 ng/ml for 20 min, white bars). Absolute values of PKM activity in untreated cells transfected with different shRNA constructs were comparable (data not shown). Asterisks denote statistical significance of obtained differences (P < 0.05 by Student’s t test). C, Lactate levels in the lysates from cells used in panel B were determined as outlined in Fig. 3E.