Sensitivity of human germ-cell-tumor cell lines to human interferons

We examined the sensitivity of four human germ-cell-tumor cell lines exhibiting different stages of differentiation to human interferons (IFNs) in vitro. The cell lines were derived from two embryonal carcinomas (NEC 8 and NEC 14), a choriocarcinoma (IMa), and a yolk-sac tumor (HUOT). Treatment with poly I:C induced IFN production in IMa and HUOT cells, but not in NEC-8 and NEC-14 cells. In the two embryonal-carcinoma cell lines, the addition of IFN-alpha, IFN-beta, and IFN-gamma did not prevent infection by vesicular stomatitis virus and encephalomyocarditis virus. Also, in these two lines, 2-5A synthetase was not induced by the addition of IFN-alpha. In contrast, both IMa and HUOT showed sensitivity to the antiviral action of IFN-alpha and IFN-beta against the two viruses, and 2-5A synthetase was induced by IFN-alpha. IFNs added at doses of up to 1000 IU/ml had no antiproliferative effect on NEC 8, NEC 14, and HUOT, whereas colony formation by IMa cells was greatly suppressed by all three forms of IFN. These results indicate that the production of and sensitivity to IFN are developmentally regulated and are related to the level of differentiation of human germ-cell stem cells.