Suppression of UV- and interferon-alpha-refractoriness by antipain in human IFr cells established from RSa cells sensitive to both stimuli.
The human cell line IFr is a variant with an increased resistance to cell proliferation inhibition (CPI) by human interferon (HuIFN)-alpha, established from RSa cells with unusually high-sensitivity to CPI. IFr cells were later found to have increased resistance to the cell-killing effects of far-ultraviolet (UV) irradiation. Here, in cell lysates extracted from UV-irradiated IFr cells but not in those from irradiated RSa cells, fibrinolytic protease activity was found to be elevated promptly and transiently after irradiation. Treatment of IFr cells with HuIFN-alpha alone also resulted in the elevation of protease activity, but not that of RSa cells. Both the activity elevated after UV irradiation and after HuIFN-alpha treatment was inhibited to the greatest extent by antipain in vitro. Moreover, the refractoriness of IFr cells to UV cell-killing and to HuIFN-alpha CPI was suppressed by culturing with medium containing antipain immediately after UV irradiation or during HuIFN-alpha exposure. In similarly treated RSa cells, there was no modulation of UV- or HuIFN-alpha-susceptibility. These comparative characteristics between the two cell lines suggested that antipain-sensitive proteases and/or cellular functions may be involved in increased resistance to UV and HuIFN-alpha of IFr cells.
Suzuki
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Department of Biochemistry, School of Medicine, Chiba University, Japan.
D000976:Antipain / Q000494:pharmacology*; D002454:Cell Differentiation; D002455:Cell Division / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects / Q000528:radiation effects; D004351:Drug Resistance; D010450:Endopeptidases / Q000378:metabolism*; D006801:Humans; D016898:Interferon-alpha / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology*; D014466:Ultraviolet Rays
D016898:Interferon-alpha; D011480:Protease Inhibitors; D000976:Antipain; D010450:Endopeptidases