Fig 2: Suppression of HSF1 expression by specific siRNA induces downregulation of the PI3K/AKT/mTOR pathway(A) In HLE cells, silencing of HSF1 for 48 h resulted in the downregulation of PIK3CA (an upstream inducer of AKT), phosphorylated/activated AKT and downstream AKT effectors involved in lipogenesis (p-RPS6, FASN, ACAC, SCD1) and glycolysis (ALDOA, LDHA/C, PKM2), as detected by Western blot analysis. (B) Equivalent results were obtained in HLF cells. ß-Actin was used as a loading control.

Fig 3: Suppression of hepatocarcinogenesis following HSF1 inactivation is accompanied by downregulation of activated AKT and its downstream effectors in the mouse liver(A, B) Representative Western blot analysis of livers from control mice (injected with empty vector), AKT mice (injected with myr-AKT1) and AKT/HSF1dn mice (co-injected with myr-AKT1 and HSF1dn). Inactivation of HSF1 in AKT/HSF1dn mice resulted in downregulation of phosphorylated/activated AKT. Levels of some AKT upstream (PIK3CA) and downstream effectors (p-RPS6, p-NDRG1, FASN, ACLY, ACAC, SCD1, PPARG, ALDOA, LDHA/C, PKM2) were downregulated in AKT/HSF1dn mice when compared with AKT mice. As expected, livers from AKT/HSF1dn mice were the only ones to express the transfected HSF1dn construct (V5-tagged). Of note, the levels of some of the proteins tested were even lower in AKT/HSF1dn mice than in control mice. Ten livers from each group of mice were used for the analysis, and representative images are shown. ß-Actin was used as a loading control. (C–F) Fatty acid biosynthesis, cholesterol and triglyceride content, and lactate dehydrogenase activity were strongly induced in the livers of AKT mice, and equally lower in control and AKT/HSF1dn livers. Tukey–Kramer test: P < 0.0001 a, vs control (mice injected with empty vector); b, vs AKT mice. Abbreviations: FA, fatty acid; CE, cholesterol; TG, triglycerides; LDH, lactate dehydrogenase.