Fig. 6. ^Thr172P-Cdk4/Cdk4 (A) and ^Ser15P-p53/p53 (B) ratios in Tacrolimus-, Sirolimus- and Everolimus-treated HepG2 cells; as well as p21 protein expression in Tacrolimus-, Sirolimus- and Everolimus-treated HepG2 (C) and Huh7 (D). Treatments were administered at different concentrations (0, 10 nM, 10 µM, and 100 µM). The protein expression of ^Thr172P-Cdk4 and Cdk4 (6 h), ^Ser15P-p53 and p53 (12 h), and p21 (12 h) was determined by Western‐blot analysis. Results are expressed as mean ± SEM, and blots are representative of three to five independent experiments. *p ≤ 0.05, **p ≤ 0.01 and ***p ≤ 0.001 between control and immunosuppressant‐treated cells. The groups with different letters (a, b, c, d or e) were significantly different (p ≤ 0.05).