CDA-2 induces cell differentiation through suppressing Twist/SLUG signaling via miR-124 in glioma.

Cell differentiation agent-2 (CDA-2) is an extraction from healthy human urine consisting of primary organic acids and peptides, and it has been demonstrated to inhibit growth and induce differentiation in glioma and other cell lines. But the mechanism of CDA-2 remains unclear. In this study, we demonstrated that CDA-2 inhibited cell growth and induced differentiation of glioma cells, accompanied with decreased expression of SLUG, Twist and Vimentin in both SWO-38 and U251 cell lines. Overexpression of SLUG or Twist greatly eliminated the efficiency of CDA-2 in inducing differentiation. Further study showed that CDA-2 treatment resulted in great changed microRNAs (miRNAs) detected by quantitative PCR, in which miR-124 was one of the most changed miRNAs and its level was increased by fourfold. The result of miRNA target prediction showed that miR-124 could regulate hundreds of genes which were relative to cell differentiation, such as SLUG, Vimentin, actin cytoskeleton, focal adhesion, tight junction. Inhibition of miR-124 up-regulated SLUG, Twist and Vimentin proteins, and partly eliminated the function of CDA-2 on these mesenchymal markers. Our findings demonstrated for the first time that CDA-2 induced cell differentiation through suppressing Twist and SLUG via miR-124 in glioma cells.