Prolactin enhances insulin-like growth factor I receptor phosphorylation by decreasing its association with the tyrosine phosphatase SHP-2 in MCF-7 breast cancer cells.

Normal mammary development requires coordinated interactions of numerous factors, including prolactin (PRL) and insulin-like growth factor I (IGF-I), both of which have also been implicated in breast cancer pathogenesis and progression. We previously reported that PRL and IGF-I synergize in breast cancer cells to activate ERK1/2 and AKT, leading to increased proliferation, survival, and invasion. Intriguingly, PRL co-treatment with IGF-I augments IGF-I receptor (IGF-IR) phosphorylation 2-fold higher than IGF-I alone.

Biological implications of polydimethylsiloxane-based microfluidic cell culture.

Polydimethylsiloxane (PDMS) has become a staple of the microfluidics community by virtue of its simple fabrication process and material attributes, such as gas permeability, optical transparency, and flexibility. As microfluidic systems are put toward biological problems and increasingly utilized as cell culture platforms, the material properties of PDMS must be considered in a biological context. Two properties of PDMS were addressed in this study: the leaching of uncured oligomers from the polymer network into microchannel media, and the absorption of small, hydrophobic molecules (i.

Complex prolactin crosstalk in breast cancer: new therapeutic implications.

The contributions of prolactin (PRL) to breast cancer are becoming increasingly recognized. To better understand the role for PRL in this disease, its interactions with other oncogenic growth factors and hormones must be characterized. Here, we review our current understanding of PRL crosstalk with other mammary oncogenic factors, including estrogen, epidermal growth factor (EGF) family members, and insulin-like growth factor-I (IGF-I).

SRC family kinases accelerate prolactin receptor internalization, modulating trafficking and signaling in breast cancer cells.

Despite the growing body of evidence supporting prolactin (PRL) actions in human breast cancer, little is known regarding PRL regulation of its own receptor in these cells. Ligand-initiated endocytosis is a key process in the regulation of receptor availability and signaling cascades that may lead to oncogenic actions. Although exposure to exogenous PRL accelerates degradation of the long isoform of the PRL receptor (lPRLR), neither the signals initiated by PRL that lead to lPRLR internalization and subsequent down-regulation, nor the relationship to downstream pathways are understood in breast cancer cells.

Prolactin does not require insulin-like growth factor intermediates but synergizes with insulin-like growth factor I in human breast cancer cells.

Insulin-like growth factor (IGF)-II is a required intermediate for prolactin-induced up-regulation of cyclin D1 and proliferation in normal murine mammary epithelial cells in vivo and in vitro. However, we have recently shown that prolactin can rapidly induce cyclin D1 protein expression and subsequent proliferation in the MCF-7 human breast cancer cell line, suggesting that prolactin actions can be independent of IGFs in breast disease. Here, we investigate the relationship between these factors and show that prolactin up-regulated transcript levels of both IGF-I and IGF-II, but only after increases in cyclin D1 protein were observed.