title: Long-term primary culture of a clear cell ovarian carcinoma reveals an epithelial-mesenchymal cooperative interaction.
abstract: BACKGROUND
  We studied a primary culture developed from a biopsy of a clear cell carcinoma of the ovary (O-CCC) by (a) assessing its capacity to retain in vitro pathological features of the tumor of origin; (b) characterizing the main cells released from the complex mass without forced purification of any particular cellular entity; and (c) investigating its long-term proliferative capacity.
  
  
  METHODS
  A primary cell culture was developed from a pelvic mass diagnosed as an O-CCC. The morphological analysis of the cell culture was carried out by phase contrast microscopy. Markers of epithelial, mesenchymal, and tumor initiating cells were evaluated by immunocytochemistry. Cell proliferation was studied by detection of bromodeoxyuridine (BrdU) incorporated into newly synthesized DNA. As a biomarker of O-CCC, we assessed the expression of hepatocyte nuclear factor (HNF) 1β.
  
  
  RESULTS
  We show that cells with epithelial morphological features express E-cadherin and expand with time in culture, a fact that the incorporation of BrdU confirms. Cells with mesenchymal-like characteristics that express the mesenchymal marker vimentin, however, allocate to the edges of the epithelial compartment. Moreover, we found that some cells with epithelial features also expressed vimentin. At the beginning of incubation, over 60 % of primary cells expressed the O-CCC marker HNF1β; such percentage declined upon passaging. We show that epithelial not mesenchymal cells undergo DNA replication, and that few cells in both epithelial and mesenchymal compartments express the stem-like tumor antigen CD133.
  
  
  CONCLUSIONS
  We provide proof-of-principle that cells separated in bulk from a biopsy of an O-CCC can be maintained in culture for several months, and that two consistent cellular compartments-one epithelial that retains the O-CCC marker HNF1β, and another mesenchymal-persist, and seem to have a cooperative interaction leading to the multiplication of epithelial cells within a mesenchymal cellular environment.
authors.affiliation: Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, Vermillion, SD USA ; Department of Pathology, Faculty of Medicine, McGill University, 3775 University Street, Montreal, QC H3A 2B4 Canada.
authors.forename: Alicia A
authors.initials: AA
authors.lastname: Goyeneche
authors.affiliation: Department of Pathology, Sanford School of Medicine, The University of South Dakota, Sioux Falls, SD USA.
authors.forename: Michael
authors.initials: M
authors.lastname: Koch
authors.affiliation: Department of Obstetrics and Gynecology, Sanford School of Medicine, The University of South Dakota, Sioux Falls, SD USA.
authors.forename: Maria C
authors.initials: MC
authors.lastname: Bell
authors.affiliation: Division of Basic Biomedical Sciences, Sanford School of Medicine, The University of South Dakota, Vermillion, SD USA ; Department of Obstetrics and Gynecology, Sanford School of Medicine, The University of South Dakota, Sioux Falls, SD USA ; Department of Pathology, Faculty of Medicine, McGill University, 3775 University Street, Montreal, QC H3A 2B4 Canada.
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Telleria
keywords: E-cadherin; Epithelial; Hepatocyte nuclear factor 1β; Mesenchymal; Ovarian clear cell carcinoma; Vimentin