Fig. 1.

Interferon-α-induced up-regulation of HIF-1α expression in cancer cells is heterogeneous, but concentration- and time-dependent. a Most of cancer cell lines responded to interferon-α (IFN-α) with higher HIF-1α protein expression. b-c IFN-α induced HIF-1α expression in 769P cells is dose- (b, fix 24 h, indicated dosage) and time-dependent (c, fixed 1000 units/ml IFN-α, indicated times). d IFN-α specific antibody attenuated IFN-α induced HIF-1α expression, (e) 769P cells treated with IFN-α for 24 h had a dose-dependent (500, 1000 and 3000 units/ml) elevated expression of HIF-1α and ISG15, but not that of HIF-1β. f IFN-α (1000 units/ml) and IFN-γ (100 ng/ml), but not lipopolysaccharide (LPS, 10 μg/ml), greatly elevated HIF-1α expression. g IFN-α induced HIF-1α expression was majorly on the nucleus fractions, but not cytoplasm