Progestins modulate miRNAs expression in breast cancer cells. A, Heat map depicting the expression profile of miRNA genes with changes ≥2 fold after 24 hours of MPA treatment. Total RNA was extracted from primary cultures of C4HD cells treated with 10 nM MPA or left untreated for 24 hours and used for miRNA profiling with the Applied Biosystems Mouse Low Density qPCR miRNA Array (n = 4). The small nuclear RNA U6 (U6 snRNA) was used as an endogenous control to normalize the results. B, Average fold changes of miRNAs significantly modulated by MPA (P < 0.05, n = 4) in primary cultures of C4HD cells. Each graph depicts the fold change of a specific miRNA in C4HD cells treated with MPA or left untreated; all values were normalized to U6 snRNA. The data shown represent the means of three independent experiments ± SEM (P < 0.01 for b versus a). MPA, medroxyprogesterone acetate; SEM, standard error of the mean.