2′‐Phosphodiesterase Activity in Human Cell Lines Treated or Untreated with Human Interferon

Abstract
2''-Phosphodiesterase activity was investigated, by measuring either the disappearance of (2''-5'')oligo(adenylate) or the release of 5''AMP, in several human cell lines ([neoplastic embryonic] RSa, [neoplastic fibroblast] IFr, [uterine carcinoma] HEC-1, [wheat germ agglutinin-resistant RSa] WGAr and [cervical carcinoma] HeLa) possessing different sensitivities to interferon, and treated or untreated with human interferon. In various cell lines whose (2''-5'')oligo(adenylate) synthetase was normally induced by interferon treatment, both kinetic studies and measurements at different enzyme concentrations indicated that 2''-phosphodiesterase activity remained unchanged after interferon treatment. This observation was confirmed over a broad range of substrate concentrations (1-25,000 nM). The activity of 2''-phosphodiesterase was dependent on Mg(OAc)2. In various human cell lines the modulation of (2''-5'')oligo(adenylate) metabolism by interferon does not involve an increase of 2''-phosphodiesterase activity.