Figure 8.

Ellagic acid-induced SIRT6 overexpression ameliorates Dox-induced cytotoxicity in cardiomyocytes but exacerbates Dox-induced cytotoxicity in cancer cells. (A) The 2D structure of ellagic acid. (B) The 3D binding model of ellagic acid and SIRT6. The ellagic acid is colored in cyan. The surrounding residues in the binding pocket are colored in yellow. The backbone of the receptor is depicted as gray cartoon. The hydrogen bond and Pi–Pi stacking interaction are depicted as green dashed lines. (C, D) After treatment with different concentrations of ellagic acid for 24 h, the expression of SIRT6, SGK1, H3K9 and H3K56 in primary cardiomyocytes isolated from WT mice and LLC cells was examined by Western blotting. β-Actin was used as a loading control. Semiquantitative analyses of bands were performed using ImageJ software (n = 3 different experiments). (E, F) Primary cardiomyocytes isolated from WT mice and LLC cells were transfected with SIRT6 siRNA or control siRNA. After pre-treated with ellagic acid (10 μmol/L) for 24 h, Dox (0.5 μmol/L) was added to culture medium for subsequent 24 h, and apoptosis was analyzed by TUNEL assays. Representative images are shown (scale bar = 100 μm). The TUNEL-positive rates were quantified blindly in 5 images from different fields. The data are expressed as the mean ± standard deviation. Two-tailed unpaired t tests were performed to determine significant differences in D. One-way ANOVA followed by Bonferroni multiple comparisons were performed to determine significant differences in E and F. ∗P < 0.05, ∗∗P < 0.01, and ∗∗∗P < 0.001 compared to the control group. ^#P < 0.05, ^##P < 0.01, and ^###P < 0.001 compared to the Dox-treated group. n.s., no significance.