Figure 2
From: Specific inhibition of one DNMT1-including complex influences tumor initiation and progression
Impact of specific inhibition of DNMT1/protein-x interaction. (A) Tumorigenicity test of Astro#40 cells transfected with plasmids encoding for indicated peptides or pre-treated with procainamide. For each condition, five subcutaneous injections of 106 cells were performed in Swiss nude nice. Picture illustrates the tumor obtained (or not) 5 weeks after injections. (B) Tumorigenicity test of U87 cells transfected with plasmids encoding for indicated peptides or pre-treated with epigenetic drugs. For each condition, three subcutaneous injections of 106 cells were performed in Swiss nude mice. Graph illustrates the average ± SD of these data. Picture illustrates representative tumors obtained 4 weeks after injections. (C) Effect of different DNMT inhibitor strategies. DNA methylation governs the expression of tumor suppressor genes (TSG) but also of oncogenes and DNA repeat element and retrotransposons (whose demethylation and/or expression promotes the tumorigenesis). By using an unspecific DNMT inhibitors (5aza-2deoxycytidine) or a specific DNMT1 inhibitor (procainamide), we postulate that we induced the hypomethylation not only of TSG but also of the oncogenes and retrotransposons. By reducing the effect of DNMT1 inhibition to certain specific DNMT/protein-x interactions, we still keep the opportunity to promote the expression of the TSG without promoting the hypomethylation-induced activation of retrotransposons and oncogenes. (D) Analysis of TMZ + irradiation-induced cell death in U87 cells. Percentages of cell death were evaluated by using a trypan blue stain 0.4%, and the Countess® Automated Cell Counter (Life Technology, France). Graph illustrates the average ± SD of three independent experiments. (E) Impact of the addition of 47-60DNMT1 on TMZ treatment in an in vivo model of glioma. After the tumor establishment, mice were treated with TMZ and TMZ + 47-60DNMT1 (Additional file 4: Figure S4). Two negative controls were used: “untreated” represents a treatment with DMSO “m47-60DNMT1” symbolized a co-treatment using TMZ and mutated 47-60DNMT1. Graph illustrates the average ± SD of five independent experiments.