Comparative transcriptome analysis between immortalized ovarian surface epithelial (iOSE) and immortalized fallopian tube secretory epithelial (iFTE) cells

The transcriptomes of three immortalized ovarian surface epithelial cell lines (iOSE, PMID: 17266044) and primary OSE cells (Innoprot, Derio, Spain) and four immortalized fallopian tube secretory epithelial (iFTE) cell lines (PMID: 21502498, 22936217) were compared. RNA-sequencing was done from rRNA depleted total RNA (Ribo-Zero rRNA Removal Kit) to approx. 20 million 50 bp paired end reads per sample. A discriminative gene expression signature comprised of 211 genes was developed and used to classify isolated and EpCAM enriched primary ovarian cancer cells (PMID: 25991672). Impact of this signature on overall survival was assessed from several publicly available ovarian cancer gene expression data sets. Background: High grade serous ovarian cancer (HGSOC) is characterized by extensive local, i.e. peritoneal, tumor spread, manifested in two different clinical presentations, miliary (many millet sized peritoneal implants) and non-miliary (few large exophytically growing peritoneal nodes), and an overall unfavorable outcome. HGSOC is thought to arise from fallopian tube secretory epithelial cells, via so called serous tubal intraepithelial carcinomas (STICs) but an ovarian origin was never ruled out for at least some cases. Comparative transcriptome analyses of isolated tumor cells from fresh HGSOC tissues and (immortalized) ovarian surface epithelial and fallopian tube secretory epithelial cell lines revealed a close relation between putative origin and tumor spread characteristic, i.e. miliary from tubes and non-miliary from ovaries.