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. 2020 May 22;117(23):13012–13022. doi: 10.1073/pnas.1918845117

Fig. 7.

Fig. 7.

Metformin inhibits both RB and 4E-BP1 activity in cell proliferation. (A and B) Immunoblot analysis of the MEK/ERK pathway, phosphorylated ERK1/2, total ERK1/2, Cyclin D1, CDK4/6, phosphorylated RB protein, and total RB protein (A), and the AKT/mTOR pathway, phosphorylated AKT (Thr308), total AKT, phosphorylated mTOR (Ser2448), total mTOR, phosphorylated 4E-BP1, and total 4E-BP1 (B) was conducted in SW48 and LoVo cells after treatment with 2.5, 5, and 10 mM metformin for 24 h. (C) Quantification of proteins in A and B by densitometry from three independent experiments, normalized by β-actin levels (mean ± SEM). *P < 0.05, **P < 0.01. (D–F) Phosphorylated RB protein, total RB protein, phosphorylated 4E-BP1, and total 4E-BP1 were detected by immunoblot analysis in KRASG13D SW48 and its control SW48 cells (D), sh-KRAS LoVo, and its control sh-ctrl LoVo cells (E) after treatment with 2.5, 5, and 10 mM metformin for 24 h and detected in 374469 KRASWT colon adenocarcinoma and 386650 KRASG12D colon mucinous adenocarcinoma patient-derived xenograft models after treatment with 1 mg/mL metformin in drinking water for 30 d (F). All P values were determined by two-way ANOVA. *P < 0.05, **P < 0.01.