Profiling the DNA Methylation-Mediated Cardioprotective Effect of Metformin Against Doxorubicin

Doxorubicin causes dose-dependent cardiotoxicity linked to epigenetic dysregulation, especially DNA methylation. Metformin shows cardioprotective effects through metabolic and epigenetic mechanisms. This study examined the role of metformin in counteracting doxorubicin-induced DNA methylation changes. H9c2 cardiomyoblasts were treated with doxorubicin with or without metformin (0.7–2.8 mM). Cell viability and IC₅₀ were determined by MTT assay. Genome-wide DNA methylation was analysed by whole-genome bisulfite sequencing, followed by PCA and differential methylation analysis with FDR correction. Doxorubicin reduced cell viability (IC₅₀ = 0.164 µM), while metformin increased IC₅₀ values. PCA showed clear group separation. Numerous DMRs were associated with oxidative stress, mitochondrial function, apoptosis, and chromatin regulation. Metformin induced dose-dependent genome-wide methylation changes in cardiac cells, supporting a direct epigenetic cardioprotective effect.