Overexpression of miR-199b-5p inhibits Ewing's sarcoma cell lines by targeting CCNL1

MicroRNAs (miRNAs) are known to regulate the expression of a variety of genes, which are important in the development of several types of tumor, including Ewing's sarcoma (ES), at the post-transcriptional level. Although previous studies have identified that the expression of miRNA-199b-5p was downregulated in various types of tumor, the expression levels of miR-199b-5p in ES cells remain to be elucidated. The mechanism underlying ES via the miRNA pathway remains to be elucidated. The present study demonstrated that miR-199b-5p was an important regulator in ES cells and its expression was downregulated in ES originated A673/TC252 cells. The ES cell lines, A673 and TC252, were transfected with an miR-199b-5p mimic to overexpress the levels of this miRNA. This forced expression of miR-199b-5p suppressed the cell proliferation and invasion, arrested cell cycle progression, and promoted cell apoptosis. Furthermore, CCNL1 was identified by bioinformatic software as a potential target gene of miR-199b-5p. Following this, the present study identified CCNL1 as a direct target of miR-199b-5p in ES cells. Taken together, the present study established a functional link between ES, miR-199b-5p and CCNL1, and suggested that miR-199b-5p acts as a tumor suppressor and may be of diagnostic and therapeutic importance for human ES.