The type 2 transmembrane serine protease matriptase is under tight control primarily by the actions of the integral membrane Kunitz-type serine protease inhibitor HAI-1. Growing evidence indicates that HAI-2 might also be involved in matriptase inhibition in some contexts. Here we showed that matriptase inhibition by HAI-2 depends on the subcellular localizations of HAI-2, and is observed in br...

We previously identified and characterized a novel tumor growth inhibitor and a fatty acid-binding protein in human mammary gland and named it the mammary-derived growth inhibitor-related gene (MRG). Here, the effects of MRG on mammary gland differentiation and its interaction with omega-3 polyunsaturated fatty acids (omega-3 PUFAs) on growth inhibition were investigated. MRG protein expression...

Recently, two novel concepts have emerged in cancer biology: the role of so-called "cancer stem cells" in tumor initiation, and the involvement of an epithelial-mesenchymal transition (EMT) in the metastatic dissemination of epithelial cancer cells. Using a mammary tumor progression model, we show that cells possessing both stem and tumorigenic characteristics of "cancer stem cells" can be deri...

We previously identified and characterized a novel tumor growth inhibitor and a fatty acid-binding protein in human mammary gland and named it the mammary-derived growth inhibitor-related gene (MRG). Here, the effects of MRG on mammary gland differentiation and its interaction with v-3 polyunsaturated fatty acids (v-3 PUFAs) on growth inhibition were investigated. MRG protein expression was ass...

We previously identified and characterized a novel tumor growth inhibitor and a fatty acid-binding protein in human mammary gland and named it the mammary-derived growth inhibitor-related gene (MRG). Here, the effects of MRG on mammary gland differentiation and its interaction with v-3 polyunsaturated fatty acids (v-3 PUFAs) on growth inhibition were investigated. MRG protein expression was ass...

p21-Activated kinase-1 (Pak1) is frequently upregulated in human breast cancer and is required for transformation of mammary epithelial cells by ErbB2. Here, we show that loss of Pak1, but not the closely related Pak2, leads to diminished expression of β-catenin and its target genes. In MMTV-ErbB2 transgenic mice, loss of Pak1 prolonged survival, and mammary tissues of such mice showed loss of ...

Mammary epithelial cells undergo changes in growth, invasion, and differentiation throughout much of adulthood, and most strikingly during pregnancy, lactation, and involution. Although the pathways of milk protein expression are being elucidated, little is known, at a molecular level, about control of mammary epithelial cell phenotypes during normal tissue morphogenesis and evolution of aggres...

Previous studies have demonstrated that normal mammary tissue contains a hierarchy of cell types that are ultimately and continuously derived from a self-sustaining mammary stem cell population. However, a suitable assay for detecting, quantifying and characterizing such cells in humans has been lacking. Here we show that histologically normal, bi-layered mammary epithelial structures containin...