Abstract 4246: Long-term primary culture of a mucinous ovarian adenocarcinoma containing CD133 positive cells

Abstract

Abstract Among epithelial ovarian cancers, mucinous ovarian cancer (MOC) is rare but highly lethal. In this work, we describe the successful long-term primary culture of a heterogeneous population of cells derived from a tumor biopsy obtained from a 50 yr old patient diagnosed with stage IIIc ovarian cancer that underwent debulking surgery. The tumor was hemorrhagic and pathologically classified as a MOC. To understand the biological behavior in culture of this rare tumor type, the tissue biopsy was enzymatically digested, and the bulk of the cells were allowed to attach to regular tissue culture flasks. After 24 h in culture, the cells that adhered to the plate formed colonies of epithelial appearance. Such colonies were however surrounded by cells with mesenchymal phenotype. We considered the latter cells as part of the tumor microenvironment, and, consequently did not intend to separate them from the epithelial cells-a method that has been traditionally used to generate epithelial cancer cell lines. After two months of incubation and with periodic media changes, the culture still displayed a combination of epithelial-mesenchymal phenotype. When we compared the phenotype observed in photographs taken four days after initial plating versus those taken two months later, it was clear the net growth of the epithelial, but not the mesenchymal component of the culture. The growth of the epithelial component was confirmed by BrdUrd incorporation. Of notice, each epithelial foci was always closely surrounded by mesenchymal-like cells; when the mesenchymal component of the culture was removed to enrich the epithelial cell population, the epithelial cells stopped growing and underwent quiescence. In the mixed culture, the cells with epithelial morphology stained mostly positive for E-cadherin and negative for vimentin, whereas the opposite occurred for the cells with mesenchymal morphology. Curiously, some cells in the periphery of the epithelial compartment where positive for the mesenchymal marker vimentin, suggesting the existence of a “transitional” epithelial-mesenchymal phenotype. We studied the expression of the stem cell marker CD133 and of the endothelial marker CD31. We found CD133 positive cells in both epithelial and mesenchymal compartments, whereas CD31 positive cells were only found in the mesenchymal area. In conclusion, this study demonstrates that it is feasible to maintain in culture, for a relatively long period of time, a complex mixture of cells obtained from a primary MOC. We show that it is the complexity of the cellular components what allows the culture to grow, confirming in vitro the importance of the tumor microenvironment for the successful proliferation of the ovarian epithelial cancer cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4246. doi:1538-7445.AM2012-4246