Cultures of normal human mammary cells.

This paper describes a method of obtaining epithelial cells from large quantities of normal human breast tissue and the response of these cells in culture to lactogenic hormones. Suspensions of single cells and clusters of cells resembling normal ductal and alveolar structures were obtained by mechanical disaggregation and subsequent (3h) incubation of tissue fragments in 0.5 mg/ml collagenase. Cells rapidly attached to glass or plastic surfaces within 48 h and grew to form large colonies which maintained their epithelial appearance throughout 2 months of observation. Cell cycling as monitored by DNA synthesis was enhanced by insulin, hydrocortisone, or ovine prolactin (in concentrations of 5.0mug/ml each) at respectively 2,3 and 5 days of incubation. These results were observed in cultures derived from 3 premenopause samples of mammary tissue maintained in medium with 1% fetal calf serum. Prolactin at a concentration of 5 mug/ml induced phosphoprotein synthesis 8-fold over control values. In addition, prolactin induced morphological changes in cells including the development of distended endoplasmic reticulum, large microvilli, and the deposition of glycogen granules. These initial results led to the tentative conclusion that prolactin was sufficient to initiate some of the characteristics in cultured cells normally associated with lactating tissues.