3.

PKM2-null reduces metabolic flux of glutamine to Ac-CoA and sensitizes cells to hypoxia conditions. (A) Schematic for metabolic flux of glutamine to Ac-CoA through the reductive pathway via the backward CAC. (B–D) Mass isotopomer analysis of succinate, succinyl-CoA, and Ac-CoA in 4T1 cell lines, 4T1/Cas9, 4T1/PKM-KO, 4T1/KO+hPKM1, and 4T1/KO+hPKM2 cells cultured with ¹³C₅-glutamine for 8 h. (E) Schematic for metabolic flux of glutamine to Ac-CoA through the forward CAC and malic enzyme (ME). (F) Relative ratio of α-ketoglutarate/isocitrate and α-ketoglutarate/citrate in 4T1 cell lines. (G) Proliferation rate of 4T1 cell lines, 4T1/Cas9, 4T1/PKM-KO, 4T1/KO+hPKM1, and 4T1/KO+hPKM2 cells under normoxia and hypoxia conditions. (H) Glucose uptake of 4T1 cell lines, 4T1/Cas9, 4T1/PKM-KO, 4T1/KO+hPKM1, and 4T1/KO+hPKM2 cells under normoxia and hypoxia conditions. (I) Lactate production of 4T1 cell lines, 4T1/Cas9, 4T1/PKM-KO, 4T1/KO+hPKM1, and 4T1/KO+hPKM2 cells under normoxia and hypoxia conditions. In all panels, error bars indicate SD (n = 3). *P < 0.05, ** P < 0.01.