Fig. 3

Decreased miR-125a expression is caused by hypermethylation of its upstream/promoter region and can be increased by HMA treatment. a miR-125a expression was assessed by qPCR in the myeloid cell lines THP1, U937, and NB4 after treatment with 5 µM decitabine for 48 h. For comparison of the different conditions, respective control situations (treated with the empty dissolvent only) were set at a value of 1. The relative increase in miR-125a expression in the decitabine-treated conditions was calculated as the ratio of decitabine-treated to control-treated expression levels. b miR-125a expression after treatment with 2.5 µM azacitidine for 24 h. The relative increase in miR-125a expression in the azacitidine-treated conditions compared to controls is displayed. Graphs denote the mean ± SD of at least three independent experiments. Comparisons against the control condition were performed using a one-sample t test against a reference value of 1. Of note, the increase in miR-125a expression could also be observed after incubation with a lower azacitidine concentration (1 µM; Additional file 1: Fig. S4) c Eight CpG-sites within a CpG-rich region upstream of miR-125a [23] were studied by bisulfite sequencing in U937 cells before and after treatment with 2.5 µM azacitidine for 24 h. This region roughly correlates to the miR-125a promoter region [52]. The panel on the left demonstrates the percentage of methylated sequencing reads for each CpG site studied; the panel on the right depicts the mean percentage of methylation across all eight CpG sites ± SD. Statistical differences were assessed with the t test. Aza, azacitidine; Dec, decitabine