Feasibility of the use of primary breast epithelial cell cultures to identify genotype-specific preventive agents

Abstract

3140 Background: Recent progress has intensified efforts to discover agents that target genetically determined events in order to treat, or even prevent, cancer. We have chosen to study clinically normal cells from Li Fraumeni Syndrome (LFS) and BRCA2 mutation carriers, individuals who carry a dominantly inherited increased risk for breast cancer. Our purpose was 1) to determine the feasibility of initiating short-term breast epithelial cell cultures from normal breast parenchyma obtained from incisional or core biopsies, and 2) to determine the effects of potential chemopreventive agents on growth inhibition of clinically normal cells from gene-carriers and controls. Methods: Uninvolved breast parenchyma was obtained from mastectomies for breast cancer, or contralateral prophylactic mastectomies, via incisional or 16G core biopsy. Specimens were digested in collagenase, and epithelial cells grown in MEGM (Clonetics, CA). Epithelial cell growth (passage 2–3) after 72 hours’ drug treatment was assessed with sulforhodamine B assay. Results: Breast epithelial cells were cultured from 28 (93%) of 30 incisional biopsies, with 100% success in the last 15. Cultures were initiated in 24 (83%) of 29 samples from 4 core biopsies, with 100% success in the last 20. Epithelial cells from four patients with LFS, two with BRCA2, and six controls were treated with tamoxifen, celecoxib, 4HPR, SAHA, CP31398, and rapamycin. All agents produced similar growth inhibitory effects for most genotypes. However, there was a trend toward more pronounced growth inhibition of LFS cells than of controls with p53-stabilizing agent CP31398 (28.3% vs 15% at 10 μM, p=0.08). Conclusions: It is feasible to culture breast epithelial cells from incisional as well as core biopsies, holding promise for individualized in vitro testing of chemopreventive agents. The agents in our study appear to have growth inhibitory effects in all genotypes tested. Further work is needed to determine whether novel genotype-specific preventive agents can be identified and temporal and concentration-dependent short-term biomarkers of response can be developed with this in vitro approach. Supported by NCI grant NO1-CN-15102 (to L.C.S.). No significant financial relationships to disclose.