Fig. 1

miR-503 downregulation affects cancer properties in MM in vitro. A NGS expression values of DEG miRNAs selected after single CDDP and combined CDDP/P treatments and q-PCR validation in MM cells. B Effects on cell viability of miR-503 inhibition at different time. 48 h treatment resulted the best time and reduction was 46% MSTO, 66% NCI and 43% Mes2. A lower decrease was detected after 24 h (75% MSTO, 68% NCI and 84% Mes2) while after 72 h the effect was comparable to the 48 h (49% MSTO, 69% NCI and 50% Mes2). C FACS analysis confirms that cell viability decrease after 48 h treatments is due to apoptotic increase in all MM cells treated with anti-miR-503 (33% MSTO, 35% NCI and 16% Mes2) compared to nc-anti-miR-503 (6% MSTO, 4% NCI and 4% Mes2), used as control. Histograms report a data summary of the apoptotic index for both treatments. D Crystal violet colony assay in MM cells transfected for 48 h with anti-miR-503 or with negative control (nc-anti-miR-503). Cells were grown for 7 days before transfection and after additional 7 days the colonies were stained with 0.4% (w/v) crystal violet and counted using Image J. Reduction of colony numbers were: 50% MSTO, 50% NCI and 45% Mes2. Data are shown in the histogram. E Wound-healing assay shows that miR-503 inhibition after 48 h greatly reduced the migration capability of MM cells. The graph reports the residual gap in treated anti-miR-503 cells compared to control (80% MSTO, 80% NCI and 76% Mes2). Data are presented as the mean ± SD of at least three independent experiments (n = 3). **p < 0.01 ***p < 0.001 ****p < 0.0001 vs. control