PMC42, a novel model for the differentiated human breast

Cultured human breast carcinoma cell lines are important models for investi gating the pathogenesis of breast cancer. Their use, however, is limited be cause of loss of expression of breast-specific markers and the development of a dedifferentiated phenotype after continuous culture. PMC42 is a unique human breast carcinoma line, previously shown to express secretory and myo epithelial markers. We have induced PMC42 cells to form hollow organoids in culture, similar to in vivo breast structures, using a combination of horm ones including estrogen, progesterone, dexamethasone, insulin, and prolacti n in combination with a permeable extracellular matrix. The organoids compr ised polarized cells located around a central lumen. Expression of beta -ca sein was demonstrated in cells within organoids using reverse transcriptase -polymerase chain reaction, Western blot analysis, and confocal immunofluor escence, In this in vitro system, milk-specific gene expression was induced through hormone and matrix interactions which may be similar to those oper ating in vivo, PMC42 is a novel model for investigations into the molecular mechanisms of carcinogenesis and differentiation in the human breast. (C) 2001 Academic Press.