Expression of lncRNA CCAT2 in children with neuroblastoma and its effect on cancer cell growth.

The aim of this study was to determine the expression of long-chain non-coding RNA (lncRNA) colon cancer-associated transcript 2 (CCAT2) in children with neuroblastoma and its effect on cancer cell growth. A polymerase chain reaction assay was carried out to quantify lncRNA CCAT2 miRNA in neuroblastoma cells, corresponding paracancerous cells, SH-SY5Y and SK-N-SH cells, and human umbilical vein endothelial cells (HUVEC), and two groups of children with different lncRNA CCAT2 expression were compared in clinical pathological parameters and prognosis. CCAT2-NC and si-CCAT2 were transfected into SH-SY5Y cells, separately. Then a 3-(4,5-Dimethylthiazol-2-yl)-2,5-Diphenyltetrazolium Bromide (MTT) assay was carried out to analyze the cell proliferation, migration, and invasion ability, a flow cytometry to detect cell apoptosis, and a Western blotting (WB) assay to quantify p53 and Bcl-2 proteins. lncRNA CCAT2 expression in cancer tissues of children with neuroblastoma was notably higher than that in corresponding paracancerous tissues (P < 0.05), and children with different tissue differentiation, tumor staging, and lymph node metastasis (LNM) showed notably different lncRNA CCAT2 expression (P < 0.05). In addition, children with neuroblastoma in the high lncRNA CCAT2 expression group showed lower 3-year survival rate than those in the low expression group (P < 0.05). Multivariate analysis revealed that tissue differentiation, tumor-node-metastasis staging, LNM, and lncRNA CCAT2 expression were all independent risk factors affecting the prognosis of children with neuroblastoma (all P < 0.05). Compared with HUVEC cells, SH-SY5Y and SK-N-SH cells showed notably up-regulated lncRNA CCAT2, and the expression of it in SH-SY5Y was higher than that in SK-N-SH cells (P < 0.05). Compared with the CCAT2-NC group, the si-CCAT2 group presented notably down-regulated CCAT2 (P < 0.05). Moreover, according to the MTT assay, the si-CCAT2 group showed notably weakened cell viability and proliferation than the CCAT2-NC group (both P < 0.05), and SH-SY5Y cells in the former group were less active than those in the latter group in terms of migration and invasion. The cell apoptosis rate of SH-SY5Y cells in the si-CCAT2 was higher than that in the CCAT2-NC. The results suggested that knock down of lncRNA CCAT2 could improve the apoptosis activity of neuroblastoma cells in children. According to the WB assay, the si-CCAT2 group showed notably higher p53 expression and notably lower Bcl-2 protein expression than the CCAT2-NC group (both P < 0.05). LncRNA CCAT2 can inhibit the proliferation of neuroblastoma cells and promote their apoptosis, which provides a basis for the treatment of neuroblastoma.