Fig. 1

miR-124 is downregulated in metastatic cell lines and human tissues of breast cancer. a Real-time RT-PCR quantification of miR-124 expression in normal breast tissues (Normal) and eight kinds of breast cancer cells. Expression of miR-124 was normalized against an endogenous control U6. A Student t test was used to compare miR-124 expression in each individual cell with that in normal breast tissues. * P < 0.05, ** P < 0.01. b miR-124 expression was lower in invasive breast cancer cells, including BT-549, MDA-MB-231, Hs578T, MDA-MB-468 and MDA-MB-436, than in non-invasive breast cancer cells including MCF7, T47D and BT-474. c miR-124 expression was lower in MDA-MB-231 variant with high bone metastatic potential (MDA-MB-231-B) than in parental MDA-MB-231 cells (MDA-MB-231-P). d In situ microRNA hybridization (ISH) assay of miR-124 level in 79 pairs of primary breast cancer tissues (Primary) and para-tumor tissues (Para) as well as 34 bone metastasis tissues (bone) of breast cancer. Horizontal line indicates median value. ***P < 0.001 by Mann–Whitney U test. e Representative ISH images of miR-124 expression in para-tumor tissues, primary lesions and bone metastasis tissues at an original magnification of ×40