Fig. 2
Upregulated PPP protects resistant cells from oxidative stress. a Real-time PCR analysis was performed to determine the levels of pentose phosphate pathway (PPP) enzymes. Graph represents enzyme levels in MiaPaCa/Erlo cells relative to MiaPaCa2 cells. G6PD, glucose 6-phoshate dehydrogenase; PGLS, 6-Phosphogluconolactonase; 6PGD, 6-phosphogluconate dehydrogenase; RPE, ribulose-phosphate 3-epimerase; RPI, ribulose-phosphate 4-isomerase; TKT, transketolase; TALDO, transaldolase (n = 2). b Drug-sensitive and drug-resistant cells were analyzed for G6PD levels (immunoblot) and glutathione content (glutathione detection kit) (n = 3). c DCFDA assay was performed to determine overall ROS levels in cells (top) (n = 3). Cells treated with hydrogen peroxide (H2O2) for 10 min at indicated concentration were analyzed for clonogenic survival (bottom) (n = 2). d Untreated and 6AN-treated (48 h) cells were analyzed for NADPH/NADP+ content using commercial kit (n = 2). e, f Effect of PPP inhibition (48 h 6AN treatment at indicated concentrations) was determined on cellular ROS and glutathione content in MiaPaCa/Erlo cells (n = 3). g Erlotinib-treated (48 h) cells were analyzed for ROS levels using DCFDA dye (n = 3). Data presented as average ± SEM (*p < 0.05, #p < 0.01)