DIRECT ACTION OF INTERFERON AND INDUCERS OF INTERFERON ON TUMOR-CELLS IN ATHYMIC NUDE-MICE

  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (10) , 4596-4599
Abstract
Two interferon-mediated enzyme activities, the protein kinase and pppA (2''p5''A)n synthetase (2-5A synthetase), were used to assess the presence and action of interferon on HeLa [human cervial carcinoma] tumor cells in athymic nude mice. The protein kinase is manifested by the phosphorylation of endogenous proteins with a MW of 67,000 and 72,000 in mouse and human cells, respectively. Treatment of HeLa tumor-bearing mice with mouse interferon (.alpha. and .beta.) resulted in enhanced levels of 2-5A synthetase and protein kinase (MW 67,000) activities in the spleen and lung, while there were no apparent effects on HeLa cells. In these HeLa tumor cells of human origin, the 2-5A synthetase and protein kinase (MW 72,000) activities were enhanced considerably only after treatment of mice with human fibroblastic (.beta.) interferon. When HeLa tumor-bearing mice were given injections of poly(A).cntdot.poly(U) or poly(I)-poly(C), then the 2-5A synthetase and the protein kinase activities were enhanced in tumor cells [protein kinase] as well as in the different tissues [protein (MW 67,000) kinase] of mice since both mouse and human interferons were produced under these conditions. A direct action of interferon on homologous tumor cells is indicated, and the tumor cells in an organism may themselves produce interferon and respond to their own interferon.

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