[MicroRNA383 regulates expression of PRDX3 in human medulloblastomas]

To investigate the effects of microRNA-383 (miR-383) on PRDX3 gene expression, cell proliferation and apoptosis of human medulloblastma.

PRDX3 and miR-383 RNA expression was detected by real-time quantitative RT-PCR in human medulloblastoma tumor tissue samples, Daoy cell line and normal brain tissue samples. Western blot was used to detect protein expression of PRDX3. Synthetic miR-383 mimics were transfected into Daoy cells by lipofectamine. Using Cell Counting Kit-8 (CCK-8) method, flow cytometry was used to investigate the cell proliferation and apoptosis, cells reactive oxgen species(ROS), mitochondrial membrane potential changes in each experimental groups.

Of 15 cases of human medulloblastoma tumor, 13 cases had miR-383 expression levels significantly lower than that of normal brain tissue, and 14 had PRDX3 mRNA expression levels significantly higher than that of normal brain tissue. The expression levels of miR-383 and PRDX3 in Daoy cells were 0.353 and 1.315 times than those of normal brain tissue, respectively. The protein expression levels of PRDX3 were higher in human medulloblatoma tumors and Daoy cells than that of normal brain tissue. Transfected miR-383 mimics increased the expression level of miR-383 after 24 h and 48 h was significantly higher than that of the control. In contrast, PRDX3 gene mRNA and protein expression levels were significantly decreased at 48 h compared with the control group. Using CCK-8 assay, the cell proliferation rate in the experimental group was significantly lower than that of the control group (P < 0.05). Annexin V-FITC assay demonstrated that early apoptosis rate of the experimental group (11.60 ± 0.30)% was significantly higher than those of the control group (2.3 ± 0.20)% and negative control group (10.37 ± 0.25)% (P = 0.000) after 48 h of transfection. The intracellular ROS levels after transfection at 24 and 48 h significantly increased than those of the control group. Mitochondrial membrane potential level at 24 h after transfection significantly decreased, comparing with the blank control group and the negative control group.

Compared with normal brain tissue, decreased expression of miR-383 but elevated expression of PRDX3 are medulloblastoma tumour and Daoy cell lines. Up-regulation of miR-383 knockdowns the expression of PRDX3, inhibits proliferation and promotes apoptosis of Daoy cells, leading to increased intracellular ROS and decreased levels of mitochondrial membrane potential.