DDIT4 and neoplasm: Importantly, normal SVZ cells responded in a different way; indeed, by chemically stabilizing HIF-1α, REDD1 was transiently upregulated and Akt/mTOR pathway was not inhibited, unlike in tumor cells, following exposure to high oxygen tension (Figure 3H), and Akt and Stat3 were eventually upregulated by CoCl2.