scholarly journals Extracellular vesicle-mediated MFG-E8 localization in the extracellular matrix is required for its integrin-dependent function in mouse mammary epithelial cells

2017 ◽  
Vol 22 (10) ◽  
pp. 885-899 ◽  
Author(s):  
Takuya Ooishi ◽  
Daita Nadano ◽  
Tsukasa Matsuda ◽  
Kenzi Oshima
1983 ◽  
Vol 3 (6) ◽  
pp. 982-990
Author(s):  
N S Yang ◽  
C Park ◽  
C Longley ◽  
P Furmanski

Multiple molecular forms of plasminogen activator were detected in normal human mammary epithelial cells in culture. Cells derived from (normal) breast mammoplasty specimens and grown on the surface of collagen gels exhibited three major classes of plasminogen activator isozymes (Mr = 100,000 [100K], 75,000 [75K], and 55,000 [55K]). The activity of the 100K and 75K isozymes was greatly reduced when the cells were grown on conventional tissue-culture-grade plastic surfaces. MCF-7, a human mammary carcinoma cell line, exhibited predominantly or exclusively the 55K isozyme, irrespective of the cell growth substratum. The activity of the 55K isozyme was more than twofold higher for MCF-7 cells grown on collagen gels than for cells grown on plastic. Progesterone, diethylstilbestrol, and estrogen stimulated the activity of the 55K isozyme of MCF-7 cells, but only when the cells were grown on a plastic surface. The plasminogen activator activities of the normal human mammary epithelial cells were not stimulated by these hormones, irrespective of the growth substratum. These results show that the expression of plasminogen activator isozymes by human mammary epithelial cells is subject to modulation by the extracellular matrix. Normal and malignant cells may differ in their responsiveness to these effects.


Author(s):  
Christian Schmidhauser ◽  
Connie A. Myers ◽  
Romina Mossi ◽  
Gerald F. Casperson ◽  
Mina J. Bissell

1995 ◽  
Vol 108 (2) ◽  
pp. 519-527 ◽  
Author(s):  
P.L. Jones ◽  
N. Boudreau ◽  
C.A. Myers ◽  
H.P. Erickson ◽  
M.J. Bissell

The physiological role of tenascin in vivo has remained obscure. Although tenascin is regulated in a stage and tissue-dependent manner, knock-out mice appear normal. When tenascin expression was examined in the normal adult mouse mammary gland, little or none was present during lactation, when epithelial cells actively synthesize and secrete milk proteins in an extracellular matrix/lactogenic hormone-dependent manner. In contrast, tenascin was prominently expressed during involution, a stage characterized by the degradation of the extracellular matrix and the subsequent loss of milk production. Studies with mammary cell lines indicated that tenascin expression was high on plastic, but was suppressed in the presence of the laminin-rich, Engelbreth-Holm-Swarm (EHS) tumour biomatrix. When exogenous tenascin was added together with EHS to mammary epithelial cells, beta-casein protein synthesis and steady-state mRNA levels were inhibited in a concentration-dependent manner. Moreover, this inhibition by tenascin could be segregated from its effects on cell morphology. Using two beta-casein promoter constructs attached to the chloramphenicol acetyltransferase reporter gene we showed that tenascin selectively suppressed extracellular matrix/prolactin-dependent transcription of the beta-casein gene in three-dimensional cultures. Finally, we mapped the active regions within the fibronectin type III repeat region of the tenascin molecule that are capable of inhibiting beta-casein protein synthesis. Our data are consistent with a model where both the loss of a laminin-rich basement membrane by extracellular matrix-degrading enzymes and the induction of tenascin contribute to the loss of tissue-specific gene expression and thus the involuting process.


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