Breast cancer is one of the most common cancers among women in the United States and it is the second leading cause of cancer deaths in this population. Roughly 232,000 women in the U.S. were diagnosed with malignant breast cancer in 2013 and approximately 40,000 of these patients will die. The majority of breast cancers originate in the lobular or ductal cells of the milk-producing glands. In these structures, there are two main cell types: the inner luminal cells, which are surrounded by basal myoepithelium. These cells are structurally distinct and are the precursors to variable forms of breast cancer. As such, it is important to study them not only separately but also together. Current methods for culturing human mammary epithelial cells select for those of a basal phenotype. Isolation of pure basal and luminal cell populations was accomplished by using antibody-linked magnetic beads to isolate essentially pure populations of both basal (CALLA/CD10) and luminal mammary (MUC-1/CD227) epithelial cells from organoid explant cultures. Organoids were isolated and plated on collagen I coated flasks in either DFCI (basal) or MBCM (luminal) media and cultured at 37°C in 5% CO2 to induce cell migration. The media was replenished every 2 - 3 days until the cells reached confluence. Cultured cells were harvested and immunopurified using a CALLA/CD10 or MUC-1/CD227 antibody and magnetic beads. Positively selected cells were seeded in tissue culture treated flasks and propagated with medium exchange every 2 - 3 days. Each cell population was analyzed using flow cytometry to determine their purity. The DFCI/CD10 cells were over 98% CD10 positive with very little MUC1 reactivity, suggesting that they are an essentially pure basal epithelial cell population. The cells isolated using MBCM/MUC1 appear to be a mixed population with 86% MUC1 positive luminal cells and the remainder being CD10 positive basal cells. A second round of immunopurification resulted in an isolated cell population that was greater than 95% MUC1 positive, suggesting a pure luminal epithelial cell population. This procedure has been used on several organoid preparations and has generated high cell yields in addition to high cell purity. These isolated cell types can now be tested individually for drug sensitivity.

Citation Format: Steven Hoynowski. Isolation and characterization of human breast epithelial cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1199. doi:10.1158/1538-7445.AM2014-1199