Cluster analysis of treated and untreated NB4 cell lines using the 8 human miRNAs differentially expressed and Northern blot validation of miR-223, miR-17 and miR-25. A) Cluster analysis, made only for the human miRNAs, reveals that the 8 miRNAs changed their expression after treatment. In fact, red color means that the expression of the miR is higher in NB4 cell line treated with ATRA while green color means that the expression is lower. Yellow means no variation. B, C, D) 15 μg of total RNA was loaded in each lane from two independent experiments. The membranes were probed as indicated on the side: B) miR- 17 probe and U6 snRNA probe; C) miR-25 probe and U6 snRNA probe; D) miR- 223 probe and U6 snRNA probe. Note that for the miR-17 is visualized also the precursor (prec. miR-17). T = 6 days of 0.5 mM ATRA treatment, UT = untreated.