Epithelia derived from human mammary tissue exhibits unique ion transport characteristics

Abstract

Ion transport and barrier characteristics of mammary epithelium are poorly defined for most species, including humans. MCF10a cells, derived from non‐neoplastic human mammary tissue (Cancer Res 50: 6075, 1990), were cultured on permeable supports in typical medium (DMEM/F12) for 9‐17 days in the absence and presence of cholera toxin (Ct). At all time points tested, MCF10a cells generated an electrically tight epithelial barrier (1010±110 O cm2) that exhibited a positive short circuit current (Isc; 6.1±0.3 μA cm−2) indicative of net cation absorption or anion secretion. Cells cultured in Ct exhibited greater basal Isc and greater amiloride‐sensitive Isc (4.3 vs. 2.5 μA cm−2), indicating enhanced sodium absorption. Culturing the cells in the presence of forskolin (0.2 μM) did not replicate the Ct effect. Additionally, it was shown that the effect of Ct‐enhanced amiloride‐sensitive Isc was greatest at the shortest exposure period tested, 1 day. Regardless of culture conditions, acute exposure to forskolin (2 μM) induced a modest, slowly developing increase in Isc. Bumetanide and glibenclamide (300 μM) were associated with modest reductions in Isc (<0.7 μA cm−2). These results demonstrate that MCF10a cells provide a valuable model to identify transport mechanisms and regulatory pathways that can account for the unique composition of human milk. [NIH (P20‐RR017686), KS Ag Exp Stn, and KSU SUROP support]