The Expression And Regulatory Mechanism Of MiRNA-708in Childhood Common Precursor B-cell Acute Lymphoblastic Leukemia

Background The critical function of miRNAs in the pathogenesis and prognosis of hematopoietic cancer has become increasingly apparent. However, only a few miRNAs have been reported to be altered in acute lymphocytic leukemia (ALL).Procedures Bone marrow samples (n=34) were obtained from children newly diagnosed with common precursor B-cell ALL. The patients were diagnosed using morphological, immunological, cytogenetic, and molecular standards, and treated according to the Chinese Children’s Leukemia Group2008(CCLG-2008) protocol. As controls, bone marrow was obtained from consenting individuals (n=5) who had surgery for skeleton deformity without tumor or antecedent primary hematologic abnormalities.1. To discover aberrantly expressed miRNAs in pediatric B-cell ALL, our study employed genome-wide miRNA microarray analysis and stem-loop RT-PCR to examine common precursor B-cell ALL samples.2. The target genes of miRNA-708were then identified and verified by bioinformatics software, dual-luciferase reporter assay, RT-PCR, and Western blot.3. Point mutation and dual-luciferase reporter assay were performed to verified the binding site between miR-708and CNTFR.Results 1. Significant upregulation of miR-708, miR-210, and miR-181b, and downregulation of miR-345and miR-27a were observed in common precursor B-cell ALL (common-ALL) samples (p<0.05). In addition, elevated expression of miR-708and miR-181b were found in high-risk common-ALL compared to standard and intermediate ones.2. miR-708inhibited luciferase reporter activity by binding to the3’-translated regions (3’-UTRs) of CNTFR, NNAT, and GNG12mRNA in HEK-293cell line and suppressed the protein levels of CNTFR, NNAT, and GNG12in Jurkat cells. In addition, mRNA levels of CNTFR and NNAT, but not of GNG12, were found to be downregulated in high risk common-ALL samples.3. Mutational analysis revealed that miR-708binds to the394bp to400bp sequence region of the3’-UTR of CNTFR mRNA.Conclusion specific miRNA expreesion play an important role in the pathogenesis and developing of childhood common precursor B-cell ALL. The expression level of miR-708reflects differences among the clinical types of common precursor B-cell ALL, and regulates the pathogenesis and progression of common precursor B-cell ALL by targeting CNTFR, NNAT, and GNG12.