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Objective:To screen and verify the key radioresistance genes regulated by m6A methylation in nasopharyngeal carcinoma (NPC) based on the chip data and cell experiments.Methods:The microarray data of NPC radioresistance genes, m6A regulated genes and mRNA expression profiles of NPC genes were downloaded from Gene Expression Omnibus (GEO) database. The differential genes were screened and statistically analyzed by R software. The biological processes, signal pathways and interaction networks of these genes were analyzed by bioinformatics. The m6A regulatory factors were knocked down and the radioresistant strains were constructed. The above m6A differential radioresistant genes of NPC were screened and verified by real-time reverse transcription PCR (qRT-PCR) and Western blot. The m6A modification of screened genes and their direct binding ability with methyltransferase 3 (METTL3) were verified by methylated RNA immunoprecipitation qPCR (MeRIP-qPCR). The siRNA of selected genes was transfected into NPC cells, and after treatment with ionizing radiation, cell proliferation was detected by CCK-8 assay and EdU, apoptosis and cell cycle were detected by flow cytometry, and radiosensitivity was detected by clone formation assay. The trend of differences in the abundance of Fe 2+ and lipid peroxidation between the control and EGLN3 knockdown groups after ionizing radiation treatment was compared by paired t-test. Results:Chip data GSE48501 intersected with GSE200792 and GSE53819 to obtain 6 differential genes, including EGLN3, FOSL2, ADM, JUN, VEGFA and PRDM1. The target genes of EGLN3 and FOSL2 were further screened by TNMplot and KMplot, etc. The mRNA of the target genes directly bound to METTL3 and were subjected to its mediated modification of m6A. The target genes were up-regulated in the parental cells after irradiation in a dose and time gradient manner, which were also significantly up-regulated in radioresistant cells. After EGLN3 and FOSL2 were down regulated, the proliferation activity of NPC cells was more significantly decreased after irradiation, and the radiosensitization ratio was statistically significant compared with that of NPC cells without EGLN3 and FOSL2 down-regulation. After irradiation, EGLN3 down-regulated NPC cells significantly down-regulated glutathione peroxidase 4 (GPX4) expression, increased the abundance of Fe 2+ and lipid peroxidation, which played a role in radiosensitization by inducing ferroptosis. Conclusions:EGLN3 and FOSL2 play a role in radioresistance in NPC through METTL3 mediated m6A methylation. Down-regulation of EGLN3 combined with ionizing radiation can increase the intracellular Fe 2+ abundance and lipid peroxidation and down-reuglate the expression of GPX4 in NPC cells, which can enhance radiosensitization for NPC radiotherapy by the ferroptosis pathway.
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Ferroptosis is a new form of regulated cell death discovered in recent years, which is iron-dependent cell death characterized by peroxidation of polyunsaturated fatty acid phospholipids. Recent studies have shown that radiotherapy can induce ferroptosis in cancer cells via ionizing radiation. Targeting ferroptosis plays a synergistic role in tumor suppression with radiation, which not only further deepens the connotation of radiobiology, but also provides a new perspective for tumor radiosensitization. This review systematically summarizes the occurrence and defense of ferroptosis, focusing on the key role of ferroptosis in the radiobiological effects of tumor cells and the potential application of ferroptosis in radiosensitization.
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Objective to measure the percentage of th22 cells and evaluate the levels of plasma interlukin-22(IL-22)in human peripheral blood, so as to determine their clinical significance in primary Sj?gren′s syndrome(pSS). Methods Patients with pSS were divided into three subgroups based on severity of labial gland involvement:mild,moderate and severe. Healthy people served as controls. the percentage of th22 cells and the lev-els of IL-22 in human peripheral blood from pSS patients and healthy controls were measured and compared. Results Compared to healthy con-trols,pSS patients had significantly higher percentage of th22 cells and higher plasma IL-22 levels(P < 0.05). Among pSS patients,the more seri-ous illness they had,the higher percentage of th22 cell and levels of IL-22 were observed. Severe patients had higher percentage of th22 cells and IL-22 levels than moderate patients(P < 0.05),and moderate patients had higher percentage of th22 cells and IL-22 levels than mild patients(P <0.05). Conclusion Increased peripheral IL-22-secreting th22 cells are detected in primary Sj?gren′s syndrome,which have a close association with disease severity. these data suggest that th22 and its released cytokine IL-22 may be considered as potential valuable biomarkers for severity of pSS,which may provide a novel therapeutic target for treatment.
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BACKGROUND: In the tooth regeneration and dental tissue engineering study, finding suitable stem cells are the central issues.OBJECTIVE: To isolate and culture child exfoliated deciduous tooth pulp stromal cells, and compare difference in dentin sialophosphoproteln expression prior to and following mineralization.DESIGN, TIME AND SETTING: The cell observational experiment was performed at the Central Laboratory of Daqing Oil Field General Hospital from December 2006 to December 2007.PARTICIPANTS: Dental pulp were obtained from exfoliated deciduous molar tooth of eight children aged from eight to ten, four males, four females. The possibility of infectious diseases, endocrine disease, dental caries and periodontal disease was excluded.METHODS: Deciduous teeth pulp stromal cells were obtained by tissue block adhesion method, and then cultured in DMEM with 10% fetal bovine serum for 14 days. Following digestion and passage, cells were incubated in DMEM/F12 supplemented with 50 pmol/L laevo-ascorbic acid, 10 nmol/L vitamin D3. 10 mmol/L Na β-glycerophosphate and 10-8 mol/L dexamethasone for another 14 days. Cells cultured in complete DMEM served as controls.MAIN OUTCOME MEASURES: Cell morphology and growth rule were observed under a microscope. Difference in dentin sialophesphoproteln expression was determined prior to and following mineralization using immunocytochemical staining.RESULTS: Dental pulp stromal cells from human exfoliated deciduous tooth, adhered to the wall, were polygon-shaped and characterized by large cell size and a relatively large nucleus and plenty cytoplasm after mineralization for 14 days. Over 80% cells were positive for dentin sialophosphoprotein. Non-induced cells were spindle, and only 2% cells were positive for dentin sialophosphoprotein.CONCLUSION: Odontogenic inductive culture might improve odontoblastic differentiation. It seems that human exfoliatod deciduous tooth pulp represents an new reservoir of adult stem cells with odontogenic potential.