Figure 1. BNIP3 is induced by hypoxia and downregulated by starvation. (A) Human hepatocellular carcinoma cells (SK-Hep-1), breast cancer cells (MCF-7), cervical cancer cells (HeLa), osteoblast cells (U2OS) and human embryonic kidney cells (HEK293) were respectively incubated under normoxia (21% O2), hypoxia (1% O2) for 24 h or hypoxia followed by amino acid starvation for an additional 4 h. Changes in BNIP3 levels were analyzed by western blotting. (B) Those five different human cell lines were treated with 100 μM deferoxamine (DFO) for 24 h in the normoxic condition followed by amino acid starvation for 4 h.