Fig. 5: PPP promotes cell growth and AKT activation by inhibiting PHLDA3.

a 6-AN treatment inhibits cell growth, similar to glucose starvation and PKI-587 treatment. Pten null mES cells were seeded in 3.5 cm dishes at a density of 2000 cells/well. Forty-eight hours later, the cells were treated with PKI-587 (1 µM), 6-AN (100 nM) or glucose depletion. The colony numbers were counted 7 days later (left panel), while the percentages of cells in each phase of the cell cycle and apoptosis were measured by FACS analysis after 24 h of PKI-587 (1 µM) or 6-AN (100 nM) treatment or 12 h in glucose-depleted medium (right panel, lower panel). b 6-AN treatment inhibits AKT activity, similar to the effect of PKI-587 treatment (left panel), but has no effect on the ERK and PDK1 activities (right panel). The Pten null mES cells were treated with PKI-587 (1 µM) or 6-AN (100 nM) for the indicated time periods. Cell lysates were subjected to immunoblotting with the indicated antibodies. c Overexpression or knockdown of G6PD alters the AKT activities in PC3 cells. d The PHLDA3 mRNA and protein levels are regulated by 6-AN and G6PD activity in PC3 cells. e The PPP regulates AKT activity through a PHLDA3-dependent mechanism. PHLDA3 overexpression abolished the G6PD overexpression-induced AKT activation (left), while PHLDA3 knockdown blocked the G6PD knockdown-induced AKT inactivation in PC3 cells (right). Data are presented as the mean ± SD and were compared with untreated cells. Each experiment was performed n = 3 (a) and n = 4 (d) independent times. *p < 0.05, **p < 0.001, and ***p < 0.001, based on Student’s t test (two-sided ANOVA). See also Supplementary Fig. 5. Source data are provided as a Source Data file.