Fig. 4

Resistance to glucose deprivation enhanced by PKC-ζ requires PEPCK-M. a, b Effect of PKC-ζ silencing on cell viability. MTT cell viability assay was measured in HeLa cells growing 72 h in high-glucose media (a) and glucose exhaustion media (b). Fold change was calculated to values measured at 0 h for each cell line separately. Statistical significance compared with shCtrl was determined by unpaired two-tailed Student’s t test. c, d MTT cell viability assay of control and PKC-ζ silenced HeLa (c) and SW480 (d) cells treated with inhibitor of PEPCK-M (iPEPCK-2; 5 μM) or vehicle (DMSO). Cells were grown for 72 h in media lacking glucose. Data was normalized to shPKCζ #Ctrl with DMSO. Statistical significance compared with shCtrl was determined by unpaired two-tailed Student’s t test. e Spearman’s rank order correlation analysis between the protein expression levels of PKC-ζ and PEPCK-M in HeLa sh1-PCK2 cells treated with shRNAs against PKC-ζ. Expression levels were quantified in 24 different clones by densitometry of immunoblots