| Research Abstract |
To establish an in vitro differentiation system of human germ cell tumor cells, we initially selected a cell line, NEC 14 from 9 cell lines derived from various types of human germ cell tumors. The NEC 14 line established from testicular embryonal carcinoma ( EC ) showed spontaneously a capacity for multiple differentiation in xenograft tumors in nude mice, such as glandular components, cartilagious tissue, and an extraembryonic syncytiotrophoblastic element. As a differentiation inducing reagent in vitro, we used 10 M of N,N'- hexamethylene bisacetamide ( HMBA ), since this reagent showed the most potent activity to induce apparently differentiated colonies among HMBA, retinoic acid, progesterone, DMSO, and dbc AMP.
FACS analyses revealed that the HMBA treatment reduced human EC antigen, SSEA-3, and inversely induced SSEA-1 and HLA-A, B, C antigen on NEC 14 cells. Furthermore, these HMBA-treated NEC 14 cells showed higher adhesivity to plastic substrate, and contained larger amount ( 3X ) of plasminogen activator than untreated NEC 14 cells. After prolonged culture, keratin, desmin, and vimentin were immunohistochemically identifiable on a subpopulation of these HMBA-treated cells.
In additional projects, we characterized the molecular properties of F9 embryoglycan recognized by a unique antibody in sera from patients with germ cell tumors. We also found that neuron-specific enolase ( NSE ) measurements are of diagnostic value not only for immature teratomas but also for dysgerminomas.
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