MicroRNA-186-5p represses neuroblastoma cell growth via downregulation of Eg5.

Micro RNA (miRNAs) is a kind of non coding small RNAs with negative regulation function, which plays an important role in regulating the occurrence and development of tumors. In this study, we analyzed the expression level and role of miRNA-186-5p and Eg5 in neuroblastoma and neuroblastoma cell lines SHSY-5Y, Kelly, NBL-S and SK-N-AS. Results of Real-time PCR and immunohistochemistry showed that the expression level of Eg5 in tumor tissues was higher than that in tumor adjacent tissues, while miRNA-186-5p expression level in tumor tissues was lower than that in tumor adjacent tissues. miRNA-186-5p mimics or Eg5 siRNA was transfected into SHSY-5Y and Kelly cells, CCK-8 and soft agar clone formation tests' results showed that the cell proliferation was inhibited. Flow cytometry analysis of cell apoptosis and cell cycle showed that overexpression of Mi-186-5p or down-regulation of Eg5 could promote cell apoptosis and lead to arrest cell cycle at G1 phase. Bioinformatics predicts that miRNA-186-5p can bind to the 3'UTR of Eg5. Luciferase reporter gene analysis and Western blot assay also confirmed that microRNA335-5p could target ICAM-1 to inhibit its expression. The tumor growth in nude mice inoculated SHSY-5Y cells with overexpression of miRNA-186-5p was inhibited. In a word, our study found that miR-186-5p could inhibit tumor proliferation by targeting Eg5 in neuroblastoma. This finding will help to better understand the pathogenesis of neuroblastoma and provide new insights into the treatment of tumors.