Differential Gene Expression Time Course of Normal Human Immortalized (iPrECs) vs Tumorigenic (EMP-iPrECs) Prostate Epithelial Cells during In Vitro Prostate Epithelial Cell Differentiation

The first goal of this project was to identify differentially expressed genes associated with human prostate epithelial cells (PrEC) differentiation over a 2+ week time course that are associated with and potentially required for normal PrEC differentiation (J Cell Sci 123:266-76, 2010). The second goal was to determine how these differentially expressed genes are changed when the same cells are transformed into tumorigenic cells (EMP-iPrECs) through overexpression of Erg, Myc, and shRNA to Pten (Cancer Res 74:3357-68, 2014). In the iPrECs, we readily identified many genes that were up and down regulated over time during differentiation. Genes that decreased include many cell cycle genes, and genes that increased include known differentiation markers. The EMP cells did not differentiate as previously reported and was supported by the general lack of any major changes in gene expression over the EMP time course. When iPrECs were compared to EMPs, there were over 2000 differentially expressed genes that did not overlap with the differentially expressed genes identified during the normal differentiation time course. Thus, oncogenic transformation of PrECs results in major gene expression changes and abrogates the differentiation program. Approach was to collect and isolate polyA-selected RNA from from two cell lines; normal human immortalized PrECs (iPrECs) and transformed human EMP-iPrECs, which had been subjected to an in vitro differentiation assay (J Cell Sci 123:266-76, 2010). EMP-iPrECs were generated by stable expression of Erg, Myc and shRNA to Pten iPrECs (Cancer Res 74:3357-68, 2014). Specifically, total RNA was isolated from the cells at specified time points during the course of iPrEC or EMP-iPrEC differentiation. Differentiation in untransformed cells results in a bilayer of epithelial cells- basal and luminal cells. The RNA isolated from the last two time points for iPrECs include only the luminal cells which were dissociated from the basal cells. The EMP-iPrECs did not form a bilayer, therefore all time points contain the whole population. Each time point for each cell line includes biological triplicates. Michigan State University Research Technology Support Facility Genomics Core