Fig. 2: SDH loss commits cells to rely on GPT2-mediated pyruvate transamination to maintain cell growth. | Cell Death & Disease

Fig. 2: SDH loss commits cells to rely on GPT2-mediated pyruvate transamination to maintain cell growth.

From: Pyruvate transamination and NAD biosynthesis enable proliferation of succinate dehydrogenase-deficient cells by supporting aerobic glycolysis

Fig. 2

A Labeling pattern of the indicated metabolites in cells incubated with U-13C6-glucose. MPC mitochondrial pyruvate carrier, α-KG α-ketoglutarate. In blue, cytosolic (GPT) and mitochondrial (GPT2) glutamate-pyruvate transaminase paralogues. B Intracellular levels of 13C3-alanine in Sdhbfl/fl and SdhbΔ/Δ cells cultured for 24 h in the presence/absence of the mitochondrial pyruvate carrier (MPC) inhibitor UK5099 (100 µM) in a medium containing U-13C6-glucose. Data were presented as mean ± s.e.m. of n = 3 replicates. *P < 0.05; **P < 0.01 (two-tailed Student’s t-test). C Intracellular levels of 13C3-alanine in Sdhbfl/fl and SdhbΔ/Δ cells infected with lentiviruses expressing either a non-targeting control shRNA (shNTC) or one shRNA sequence targeting Gpt2 cultured for 24 h in a medium containing U-13C6-glucose. Data were presented as mean ± s.e.m. of n = 4 replicates. *P < 0.05; **P < 0.01 (two-tailed Student’s t-test). D Number of Gpt2-silenced Sdhbfl/fl and SdhbΔ/Δ cells measured after 96 h of culture. Data were presented as mean ± s.e.m. of n = 4 replicates. ***P < 0.001 (one-way ANOVA). E Average Log2(fold change) of depletion of shRNA sequences targeting GPT2 (shGPT2) determined in 285 genomically characterized human cancer cell lines retrieved from the Project Achilles plotted in relation to their SDHB mRNA levels (microarray) retrieved from Cancer Cell Line Encyclopedia, demonstrating a correlation between sensitivity to GPT2 silencing and SDHB hypoexpression. F GPT2 mRNA expression levels (microarray GSE39716) in human pheochromocytoma and paraganglioma tumor specimens with (SDHx-mut, n = 32) or without (non-SDHx-mut, n = 13) mutations in genes encoding for succinate dehydrogenase subunits and normal adrenal medulla tissue (n = 8). Each dot indicates one sample, bold black line indicates the mean. ***P < 0.001 (Welch`s-corrected one-way-ANOVA followed by Games-Howell`s multiple comparisons test); ns: not significant. Data were tested for normality. G Correlation analysis of GPT2 and SDHB mRNA levels (transcripts per million, TPM) in n = 8 human gastrointestinal stromal tumors (GISTs) (RNAseq dataset GSE107447), lacking canonical kinase mutations hand harboring mutations in genes encoding for succinate dehydrogenase subunits. r Pearson’s correlation coefficient.

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