The expression of an Ets1 transcription factor lacking its activation domain decreases uPA proteolytic activity and cell motility, and impairs normal tubulogenesis and cancerous scattering in mammary epithelial cells.

Cell migration and invasion play a crucial role during normal and pathological development. The expression of several members of the Ets family of transcription factors has been shown to correlate with the occurrence of these processes. In the present study, we investigated the effect of the expression of Ets1-DB, the DNA-binding domain of c-Ets1, on the functional properties of NMuMG and MMT epithelial cell lines, from normal and cancerous mouse mammary tissues, respectively.

Characterization of morphogenetic and invasive abilities of human mammary epithelial cells: correlation with variations of urokinase-type plasminogen activator activity and type-1 plasminogen activator inhibitor level.

Urokinase-type plasminogen activator (uPA) and one of its inhibitors, the PAI-1, are involved in the proteolytic cascade of matrix degradation during in vivo morphogenesis or metastasis. In the present study, we have characterized the in vitro morphological behavior of human normal and malignant mammary epithelial cells and determined the levels of uPA activity and PAI-1 during these events. Two-dimensional cultures in the presence of inductive fibroblast-conditioned medium (CM) allowed migration of HBL-100 cells and MDA-MB-231 cells.

Expression of c-ets-1 and uPA genes is associated with mammary epithelial cell tubulogenesis or neoplastic scattering.

Although the inductive interactions which trigger epithelial morphogenesis have been extensively described, little is known about the transcription factors involved in these processes. During mammary gland morphogenesis, we report the expression of the transcription factor c-ets-1 and one of its target genes uPA in mesenchymal cells during early stages of epithelial invasion, and later in epithelial cells themselves. In vitro studies show that both c-ets-1 and uPA mRNAs can be induced in cultured normal mammary epithelial cells in response to medium conditioned by MRC-5 fibroblasts.