To construct the eukaryotic expression plasmid of human PRX3 and measure its expression in the HEK-293FT cells, the full-length coding region of human PRX3 was cloned by PCR and inserted into the eukaryotic expression vector pcDNA4-Xpress (A). HEK-293FT cells were transiently transfected with the recombinant plasmid. Western blot and immuofluorescence were used to detect the expression of the fusion protein. In the experiment, restriction analysis identified the construction of the recombinant plasmid and the inserted sequence was identical with that published on GenBank. Western blot and immunofluorescence confirmed the expression of the recombinant protein in transfected HEK-293FT cells. It was concluded that the eukaryotic expression plasmid of human PRX3 was constructed successfully and the recombinant could be expressed efficiently in HEK-293FT cells, which provides a sound basis for the further study on human PRX3.
Cell Line, Transformed ; Cloning, Molecular ; Embryo, Mammalian ; Eukaryotic Cells ; metabolism ; Gene Expression ; Genetic Vectors ; Humans ; Kidney ; cytology ; metabolism ; Peroxidases ; biosynthesis ; genetics ; Peroxiredoxin III ; Peroxiredoxins ; Plasmids ; genetics ; Transfection

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

METHODSPRDX3 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.

RESULTSOf 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.

CONCLUSIONSCompared 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.

Apoptosis ; Cell Line, Tumor ; Cell Proliferation ; Cerebellar Neoplasms ; genetics ; metabolism ; pathology ; Gene Expression Regulation, Neoplastic ; Humans ; Medulloblastoma ; genetics ; metabolism ; pathology ; Membrane Potential, Mitochondrial ; MicroRNAs ; genetics ; metabolism ; Peroxiredoxin III ; genetics ; metabolism ; RNA, Messenger ; metabolism ; Reactive Oxygen Species ; metabolism ; Transfection

BACKGROUND/AIMS: Oxidative stress results in protein oxidation and is implicated in carcinogenesis. Sulfiredoxin (Srx) is responsible for the enzymatic reversal of inactivated peroxiredoxin (Prx). Nuclear factor E2-related factor 2 (Nrf2) binds to antioxidant responsive elements and upregulates the expression of Srx and Prx during oxidative stress. We aimed to elucidate the biological functions and potential roles of Srx in lung cancer. METHODS: To study the roles of Srx and Prx III in lung cancer, we compared the protein levels of Nrf2, Prxs, thioredoxin, and Srx in 40 surgically resected human lung cancer tissues using immunoblot and immunohistochemical analyses. Transforming growth factor-beta1, tumor necrosis factor-alpha, and camptothecin treatment were used to examine Prx III inactivation in Mv1Lu mink lung epithelial cells and A549 lung cancer cells. RESULTS: Prx I and Prx III proteins were markedly overexpressed in lung cancer tissues. A significant increase in the oxidized form of a cysteine sulfhydryl at the catalytic site of Prxs was found in carcinogenic lung tissue compared to normal lung tissue. Densitometric analyses of immunoblot data revealed significant Srx expression, which was higher in squamous cell carcinoma tissue (60%, 12/20) than in adenocarcinoma (20%, 4/20). Also, Nrf2 was present in the nuclear compartment of cancer cells. CONCLUSIONS: Srx and Prx III proteins were markedly overexpressed in human squamous cell carcinoma, suggesting that these proteins may play a protective role against oxidative injury and compensate for the high rate of mitochondrial metabolism in lung cancer.
Adenocarcinoma/*enzymology/genetics/mortality/pathology ; Animals ; Antineoplastic Agents, Phytogenic/pharmacology ; Blotting, Western ; Camptothecin/pharmacology ; Carcinoma, Squamous Cell/*enzymology/genetics/mortality/pathology ; Cell Line, Tumor ; Humans ; Immunohistochemistry ; Lung Neoplasms/*enzymology/genetics/mortality/pathology ; Mink ; NF-E2-Related Factor 2/*metabolism ; Oxidoreductases Acting on Sulfur Group Donors/genetics/*metabolism ; Peroxiredoxin III/*metabolism ; Peroxiredoxins/metabolism ; Prognosis ; RNA Interference ; Reactive Oxygen Species/metabolism ; Transfection ; Transforming Growth Factor beta1/metabolism ; Tumor Necrosis Factor-alpha/metabolism ; Up-Regulation