miR-497/195 regulation by promoter methylation in BCP-ALL. (A) Locus of miR-497/195, with the upstream CpG island and methylated region α (chr17: 6 926 487-6 926 780) and β (chr17: 6 926 900-6 927 200, identified in this study). In the lower panel, methylation status for the xenograft samples is shown as normalized (Norm) read count. (B) Expression of miR-497 and miR-195 in pdx samples methylated (meth) or nonmethylated (unmeth) in the promoter region. (C) Expression of miR-497 and miR-195 in pdx samples methylated in region α, region α and β (α+β), or nonmethylated. (D-E) Methylation level of regions α and β upon treatment with decitabine (Deci) 0.5 µM or dimethyl sulfoxide (DMSO) in cell lines (D) NALM-6 and (E) EU-3 (697), as assessed by MassARRAY. Individual data points represent the average of biological replicates for each amplicon belonging to the indicated region. na = not available. (F-G) Expression of miR-497 and miR-195 in cell lines (F) NALM-6 and (G) EU-3 (697) after 2 or 4 days of treatment with decitabine 0.5 µM; expression relative to untreated cells. (H-I) Percentage of viable cells in (H) NALM-6 and (I) EU-3 (697) treated with decitabine 0.5 µM or DMSO. Data are presented as mean ± SD compared between groups (Mann-Whitney U test, horizontal lines).