Fig. 5

TXNIP reduction in response to PKM2 activation is probably due to depleted upstream glycolytic metabolites. a Western blot analysis showing the ability of DASA-58 (15 μM) and TEPP-46 (30 μM) in reducing TXNIP levels in the presence of the proteasome inhibitor MG132 (5 μM), whereas the presence of the translation inhibitor cycloheximide (10 μM) depleted TXNIP levels almost completely in MCF7 cells. b Western blot showing the ability of DASA-58 (15 μM) in reducing TXNIP levels in the absence of LKB1, STAT3, and AMPK. Predesigned siRNAs were used to achieve knock-down of LKB1, STAT3, and AMPK in MCF7 cells. c, d Western blot analysis showing the effects of ER signaling on TXNIP expression in the presence of DASA-58 (15 μM) in MCF7 cells. The ER blocker tamoxifen (5 μM) cannot rescue TXNIP levels in the presence of DASA-58 at short (upper panel) and long (bottom panel) time points (c). ER activation using E2 (100nM) also fails to rescue TXNIP expression in response to DASA-58 at short (upper panel) and long (bottom panel) time points (d). e Western blot showing TXNIP levels in MCF7 cells as triplicates in the presence of DASA-58 (15 μM, 72 h) alone or combined with the glycolytic inhibitor 2DG (5 mM, 24 h). Adding 2DG to the conditioned medium 24 h before the end of DASA-58 treatment period rescues TXNIP expression to the basal levels. f Schematic illustration representing the hypothesis that PKM2 activation leads to decreased upstream glycolytic metabolites leading to reduced TXNIP expression, an effect that can be counteracted with the glycolytic inhibitor 2DG