Comprehensive profiling of transcriptional networks specific for lactogenic differentiation of HC11 mammary epithelial stem-like cells

The mammary gland is an apocrine gland, and its crucial function is to produce and secrete milk. The essential components of the adult mammary gland are alveoli, which are lined by milk-secreting epithelial cells. Myoepithelial cells and a stromal compartment that are derived from embryonic ectoderm and mesoderm respectively surround the epithelial cells. Several alveoli join to form lobules that have a lactiferous duct, which drains milk into an opening of the nipple. The development of murine mammary gland initiates during E10-11.5 of embryonic state with the formation of bilateral stripes on either side of the abdomen of a developing embryo, which further organises into placodes. During puberty, these placodes differentiate into multiple mammary trees and terminal end buds under the influence of estrogen and insulin-like growth factor (IGF)8. Further development of mammary gland is triggered at a virgin stage and continues throughout the pregnancy till the end of parturition, under the influence of various hormones including epidermal growth factor (EGF), glucocorticoids (GC) and prolactin (PRL). This study provides an in-depth transcriptome analysis of the profound physiological changes brought about by the action of glucocorticoids (GC) and prolactin (PRL) in MEC.

In this study, we comprehensively analysed the gene regulatory networks of HC11 MEC in response to 1) treatment with EGF and Insulin (considered as normal MEC), 2) Primed with GC (considered as P), and 3) treatment with both GC and PRL (considered as PRL). We also cultured murine embryonic stem cells (ESC) and compared its transcriptome with normal HC11 MEC to identify the dynamics of epithelial cell-specific gene regulatory networks. This study provides an in-depth transcriptome analysis of the profound physiological changes brought about by the action of glucocorticoids (GC) and prolactin (PRL) in MEC.