Cell lysates were prepared in RIPA buffer and immunoblotting was performed as previously described (19 (link)). Nuclear fractionation was performed using the REAP cellular fractionation method, as described in (35 (link)). Antibodies used were as follows: SPHK1 (Bethyl Laboratories, Montgomery, TX), SGPL1 and HIF1α (Abcam, Cambridge, MA), HIF2α (Novus Biologicals, Littleton, CO), phospho-AKT (S473), AKT, SOX2, phospho-AMPK (T172), AMPK, c-MYC, OCT-1, PKM1/2, β-Tubulin, Histone H3, cleaved caspase 3, Snail, V5-tag and β-Actin (Cell Signaling Technology, Beverly, MA).