Fig. 4
From: ErbB3 drives mammary epithelial survival and differentiation during pregnancy and lactation
Decreased STAT5-dependent differentiation of ErbB3-deficient aMECs. a, b Mammary glands harvested from 12–15-week-old mice at 16.5 d.p.c., L1, and L5. a Samples stained using IHC for P-STAT5A/B. Representative images are shown, and original magnification is 400×. Lower panel: percentage of MECs that were P-STAT5A/B+. Each data point represents the average of two random 400× fields from a single tumor; midlines are the average of samples within the group ± SD. P values calculated using Student’s unpaired two-way t test. N = 12. b Whole tissue RNA assessed by RT-qPCR for Stat5a, Csn2, and Ck8. Relative transcript levels calculated using the ΔΔCt method, internally correcting for 36B4 gene expression. Values are shown relative to the average value obtained for ErbB3WT samples harvested at 16.5 d.p.c. Each sample was assessed in triplicate, with the average triplicate value shown by a single data point. N = 7 per time point. c–e HC11-shErbB3 and HC11-shScr cells (c, e) and parental HC11 cells (d) were serum and EGF-starved for 24 h, followed by treatment with PRL, with or without BKM120 (1 μM) for 24 h. c, d Whole cell RNA assessed by RT-qPCR for expression of Stat5a and Csn2 and quantitated as described for (b). e Representative image of serum/EGF-starved cells treated for 24 h with PRL, revealing fluid-filled acini (black arrows) in ShScr cells, but not in shErbB3 cells. f HC11-shErbB3 and HC11-shScr cells transduced with Ad.AktMyr or Ad.GFP. At 48 h after transduction, cells were serum and EGF-starved, then treated with PRL for 24 h, and assessed by western blot analysis using antibodies shown at the left. dpc days post coitus, Lact d lactation day, PRL prolactin (Color figure online)