Abstract 522: Comparison of ovarian cancer spheroids and three-dimensional cell movement with the spheroids formed by normal ovarian surface epithelial and fallopian tube epithelial cells using an in vitro culture system

Abstract

Abstract Ovarian cancer is the most lethal cause of death among gynecological cancers. Recent studies have suggested that the cells of origin of ovarian cancer might be the ovarian surface epithelial (OSE) cells and epithelial cells derived from other Mullerian ducts such as distal fallopian tube. It is believed that these cells exist as cortical inclusion cysts in the ovary, to which the extracellular matrix (ECM) proteins, proteases, secreted growth factors and chemokines from the stromal microenvironment can provide oncogenic signals in a paracrine fashion. In order to investigate the molecular mechanisms and signaling events governing these processes, we grew ovarian cancer cell lines, normal OSE and fallopian tube epithelial (FTE) primary cells as three-dimensional (3D) cultures in Matrigel, which was enriched with basement membrane proteins. Most of the cells formed spheroid structures resembling ovarian inclusion cysts, with sizes ranging from 50 to 100 μm. One cancer cell line formed spindle-like structure. The multicellular structures were stained for membrane markers and examined using confocal laser scanning microscopy. Most of the cancer spheroids were consisted of tightly packed polarized epithelial cells, as revealed by lateral β-catenin and E-cadherin staining, and GM130 staining at the apical surface outlining a central lumen. In contrast, normal OSE spheroids and FTE spheroids showed less organized structure with random β-catenin and GM130 staining. To evaluate the growth and progression of the cancer cells in response to stimuli from a stromal microenvironment, the spheroids were transferred to a collagen matrix. Interestingly, the majority of the cancer cells migrated out of the spheroids in a collective movement similar to the lymphatic metastasis observed in breast cancer. The morphology of the collectively moving cells was distinctively different from that expected from an epithelial-mesenchymal transition model. Ongoing gene expression profiling and characterization of the cells growing in the 3D spheroids will reveal the molecular mechanisms underlying the morphogenic changes and may provide insights into the growth and progression of clinical ovarian cancer from inclusion cysts. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 522.