(A, B) C2C12 cells were treated with Dotap alone or Dotap formulations of miR-21 (A) and miR-29a (B) in the presence of increasing concentrations of IMO-8503. Cells were also treated with the indicated concentrations of antagonist only in order to assess the intrinsic toxicity of the molecule. After 24h cell proliferation was assessed through MTS assay. (C, D) The same assay was performed on C2C12 cells treated as described above for 48h. Results are presented as average ± S.D. Statistical analysis was performed by a two-way ANOVA test, in particular between the Dotap and IMO-8503 only conditions and between Dotap and miR-21/miR-29a conditions. n.s indicates “not significant”. **, 0.001< P ≤0.01; ***, P ≤0.001.