Characterization of a xenograft model of human ovarian carcinoma which produces intraperitoneal carcinomatosis and metastases in mice.

A new xenograft model for human epithelial ovarian carcinoma, with extensive intraperitoneal (i.p.) carcinomatosis as the predominant disease manifestation, is described. Cells from the established NIH:OVCAR-5 cell line were injected i.p. into 6- to 8-week-old Swiss nude mice. Comparative analyses between cells cultured in vitro and tumor cells derived ex vivo were performed to assess histologic features, immunohistochemical cell markers, hormonal receptor expression, adhesion to extracellular matrix molecules and chromosomal constitution. Macroscopically, the extent of tumor development appeared to be site-dependent and tumor cell survival was dose-dependent. Advanced disease was characterized by extensive solid tumor burden and ascites with parenchymal invasion, lymphatic metastases and vascular dissemination. Individual tumor nodules exhibited developing neovasculature characterized by the absence of mature basement membrane. Despite some histologic loss of cellular differentiation in advanced disease, antigenic expression was preserved, distinguishing these cells as epithelial in origin. Karyotyping of tumor cells demonstrated multiple numeric and structural chromosomal abnormalities. Serum and ascites CA 125 levels were consistently elevated only in tumor-bearing mice. This new murine model closely resembles the aggressive disease process of human epithelial ovarian carcinoma, in which the efficacy of i.p. and systemic therapeutic modalities can be investigated.