ULTRASTRUCTURAL AND PHENOTYPIC CHARACTERIZATION OF CABA-I, A NEW HUMAN OVARIAN-CANCER CELL-LINE

We have established an ovarian cancer cell line (CABA I) from ascitic fluid obtained from a patient with papillary adenocarcinoma of the ova ry prior to drug treatment. The epithelial origin of the cell line was confirmed by morphology and by immunofluorescence analysis using anti cytokeratin antibodies. Ultrastructural analysis revealed a very irreg ular membrane surface and a clear cytoplasm rich in electron-lucent ve sicles. CABA I cells grow rapidly in culture (doubling time 18 h) in a n anchorage-independent manner. Exogenously added beta-estradiol and e pidermal growth factor (EGF) treatments did not influence cell growth rate. FAGS analysis to determine the phenotypic profile of tumor-assoc iated antigen, membrane receptor, and adhesion molecule expression ind icated that the cell line was positive for different members of the c- erbB family, for alpha 6 and beta 1 integrin receptors, and intensivel y positive for HLA class I antigens and the folate receptor. Molecular characterization revealed no mutations for c-myc and c-k-ras genes, b ut did detect an exon 5 mutation in the p53 gene. CABA I cells grew po orly as heterotransplants in nude mice, and tumors showed long latency periods. Because early (15-20) and late (55-60) passage cells maintai n the same growth and phenotypic characteristics, the CABA I cell line might provide a good in vitro model system to investigate the cellula r and molecular events involved in ovarian carcinogenesis.