Reduction by interferon-alpha of levels of c-myc protein and DNA synthesis in a human hepatoma cell line mediated by inhibition of putrescine synthesis.

Interferon-alpha inhibited increases in ornithine decarboxylase, intracellular putrescine, and DNA synthesis as human hepatoma cells were stimulated to grow. Interferon-alpha inhibited the increase in the c-myc protein level, but not its mRNA level. Added putrescine abrogated the effects on c-myc protein and DNA synthesis. Interferon-alpha seemed to inhibit the increase in the c-myc protein level post-transcriptionally by reducing the putrescine level, inhibiting DNA synthesis.