Fig. 4.

STAT5 expression is required for 4ICD induced mammary epithelial cell differentiation. (A) STAT5 western blot analysis of the HC11 mammary epithelial stable cell lines HC11/vector and HC11/4ICD transfected with scramble siRNA control or STAT5 siRNA after cells were induced to undergo differentiation in the absence of exogenous prolactin, by serum starvation for two days. Western blot of α-tubulin is included as a loading control. Superfluous gel lanes between 4ICD and 4ICD STAT5 KD were removed to condense the figure panel. Expression, normalized to β-actin, of the differentiation markers (B) β-casein and (C) WAP relative to HC11/vector control treated with scramble siRNA was determined by quantitative RT-PCR. Each quantitative RT-PCR sample was prepared in triplicate and the data represent the mean and standard error (SE) of at least three independent experiments and RNA extractions. Statistically significant differences between data sets were determined using one-way ANOVA with Bonferroni post-hoc test. Asterisks indicate p<0.05.