Modulation of antiviral activity of interferon and 2',5'-oligoadenylate synthetase gene expression by mild hyperthermia (39.5 degrees C) in cultured human cells.
The antiviral/antiproliferative/antitumor properties of interferon (IFN) are potentiated by a febrile temperature (Heron, I., and Berg, K. (1978) Nature 274, 508-510; Fleischmann, W. R., Fleischmann, C. M., Jr., and Gindhart, T. D. (1986) Cancer Res. 46, 1722-1726; Groveman, D. S., Borden, E. C., Merritt, J. A., Robins, H. I., Steeves, R., and Bryan, G. T. (1984) Cancer Res. 44, 5517-5521). To investigate the role of 2',5'-oligoadenylate (2-5A) synthetase in linking temperature with these biological functions of IFN, antiviral activities and expression of the 2-5A synthetase gene were measured simultaneously in control and type I IFN-treated HL-60 and WISH cells at the selected elevated temperature of 39.5 degrees C +/- 0.5 degrees C (herein referred to as hyperthermia). In both cell lines, the IFN-mediated antiviral effect was enhanced 3-10-fold. Concurrently, enzymatic assays and immunoblot analyses with an anti-40-kDa synthetase antibody clearly gave a 2-3-fold increase of synthetase above that observed at the normal cell culture temperature (37 degrees C). These results suggest that potentiation of 2-5A synthetase must partially account for the enhanced antiviral activity of IFN at the higher cell culture temperature. The supranormal elevation of 2-5A synthetase was accompanied by a parallel increase in the steady-state concentration of 2-5A synthetase mRNA, which is likely to contribute to the observed increase in enzyme level. Transient reporter gene expression studies using plasmid constructs carrying 2-5A synthetase gene promoter linked in tandem with chloramphenicol acetyltransferase showed that IFN-inducible chloramphenicol acetyltransferase activity was not influenced by hyperthermia, suggesting that transcription activation is an unlikely explanation for the observed 2-5A synthetase mRNA level increases. Messenger RNA stability assays showed that the half-life (t1/2) of 2-5A synthetase mRNA was extended from 2 to 4 h at 39.5 degrees C. Under identical conditions, the t1/2 of poly(A)+ RNA remained unchanged whereas the t1/2 of beta-actin mRNA was reduced. Taken together, these results are consistent with the interpretation that selective stabilization of 2-5A synthetase mRNA at the elevated temperature is a major factor contributing to the potentiation of antiviral activity of IFN by hyperthermia.
Chang
C C
CC
Department of Biochemistry and Molecular Biology, New York Medical College, Valhalla 10595.
Wu
J M
JM
D015088:2',5'-Oligoadenylate Synthetase / Q000235:genetics*; D000998:Antiviral Agents; D015152:Blotting, Northern; D002478:Cells, Cultured; D002846:Chromatography, Affinity; D003609:Dactinomycin / Q000494:pharmacology; D005334:Fever / Q000503:physiopathology*; D015870:Gene Expression; D006801:Humans; D066298:In Vitro Techniques; D007372:Interferons / Q000502:physiology*; D011061:Poly A / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics
D000998:Antiviral Agents; D012333:RNA, Messenger; D003609:Dactinomycin; D011061:Poly A; D012313:RNA; D007372:Interferons; D015088:2',5'-Oligoadenylate Synthetase