FIG. 4.

HIF-1α expression in 786-O cells restores the glycolytic gene response to hypoxia treatment. (A) Establishment and characterization of 786-O (WT-8) clones stably transfected with HIF-1α. WT-8L cells express low levels of HIF-1α, whereas WT-8H cells express higher levels of HIF-1α as demonstrated by HIF-1α Northern blot and Western blot assays. The pcDNA3 vector-transfected control WT-8V cells and parental WT-8 cells express no HIF-1α RNA or protein. HEK293 cells, whose endogenous HIF-1α mRNA (asterisk) exhibits a larger size than transfected HIF-1α mRNA (double asterisk), served as positive control for HIF-1α protein. (B) Northern blot analysis of two glycolytic genes in HIF-1α-rescued WT-8 cells, showing that LDHA and PGK-1 are induced in WT-8H cells after treatment with 1.5% O₂ for 16 h. The level of induction in WT-8H is comparable to that in HEK293 cells by endogenous HIF-1α.