Abstract 3428: Coordinated regulation of mesenchymal epithelial transition in the PMC42-LA breast cancer cell line variant

Abstract

Abstract PMC42 cells were derived from a breast cancer pleural effusion and exhibit stem cell-like features when first characterized (Whitehead, Bertoncello et al. 1983; Whitehead, Monaghan et al. 1983). The PMC42-LA subline (Ackland, Michalczyk et al. 2001; Ackland, Newgreen et al. 2003) is distinctly less mesenchymal than parental PMC42-ET cells, but both exhibit EGF- and TGFβ-inducible mesenchymal-like change. Together they provide an ideal model in which to study the regulation of epithelial-mesenchymal plasticity in a breast cancer context. We have assessed in vitro parameters including migration, 3D colony formation and EMT marker expression, and undertook both miRNA profiling (mirVana probe set V1, Ambion) and alternative splice usage (Affymetrix human 1.0 ST whole genome exon arrays) analysis. Several miRNAs were expressed differently in the two sublines and/or up- or down-regulated in response to EMT-inducing treatments. Relative to the mesenchymal ET subline, the, miR-200 family members were elevated in the epithelial LA subline, where a corresponding loss of Zeb1 expression was seen. The LA subline also showed reduced E-Cadherin promoter methylation, and increased methylation of the Zeb1 promoter. Manipulation of the miR 200 family affected the EMT marker expression in these cells, as did Zeb1 suppression with shRNA. Matrigel invasion was also inhibited with Zeb1 knockdown. Additional gene expression changes and alternative splice usage, promoter methylation changes, and miR expression changes are under study. These studies may identify molecules and pathways that are important in cell specification across the epithelial mesenchymal axis, and represent diagnostic and therapeutic targets in breast cancer. Ackland, M. L., A. Michalczyk, et al. (2001). “PMC42, A novel model for the differentiated human breast.” Exp Cell Res 263(1): 14-22. Ackland, M. L., D. F. Newgreen, et al. (2003). “Epidermal growth factor-induced epithelio-mesenchymal transition in human breast carcinoma cells.” Lab Invest 83(3): 435-48. Whitehead, R. H., I. Bertoncello, et al. (1983). “A new human breast carcinoma cell line (PMC42) with stem cell characteristics. I. Morphologic characterization.” J Natl Cancer Inst 70(4): 649-61. Whitehead, R. H., P. Monaghan, et al. (1983). “A new human breast carcinoma cell line (PMC42) with stem cell characteristics. II. Characterization of cells growing as organoids.” J Natl Cancer Inst 71(6): 1193-203. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 3428. doi:10.1158/1538-7445.AM2011-3428