Interferons and oncogenes in the control of cell growth and differentiation: working hypothesis and experimental facts

This short review summarizes available evidence for (i) growth regulatory properties of exogenous as well as recently described autocrine IFNs, (ii) down-regulation of cellular oncogene expression with emphasis on c-myc and (iii) the possible involvement of the IFN-regulated 2-5A pathway at these levels. Initially described as a part of the IFN-induced antiviral mechanism, this double-stranded RNA-activated pathway leads to the preferential degradation of viral mRNAs in IFN-treated virus-infected cells probably through localized activation at the site of virus replication. Such mechanisms could be involved in the regulation of the stability of rapidly turning over mRNAs as for instance c-myc mRNA in IFN-treated cells. Whatever the elegance of the concept, however, experimental evidence is essentially circumstantial; tools developed in our group to strengthen the demonstration are briefly described.