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Objective@#To study the oxidative damage of di- (2-ethylhexyl) phthalate (DEHP) on MCF-7 cells, and to investigate the effects of 3β-hydroxysteroid dehydrogenase (3β-HSD) gene silence or overexpression on DEHP-induced oxidative damage.@*Methods@#MCF-7 cells, 3β-HSD gene silencing cells and 3β-HSD gene overexpression cells were treated with different doses of DEHP (0,0.05,0.1,0.2,0.4,0.8 mmol/L) for 24h, then intracellular oxidative damage index such as MDA, SOD, GSH, GSH-PX were detected, DNA repair gene hOGG1, hMTH1 mRNA expression were tested by Q-PCR, hOGG1, hMTH1 protein expression were detected by western blot.@*Results@#After MCF-7 cells were treated by DEHP, MDA levels increased; SOD activity, GSH content, GSH-PX activity decreased, hOGG1 and hMTH1 mRNA expression levels increased, hOGG1 and hMTH1 protein expression levels increased, the differences were statistically significant when compared with control (P<0.05 or P<0.01) . In 3β-HSD gene silencing cells which were treated by DEHP, when compared with the same dose group of MCF-7 cells, MDA content increased, SOD activity, GSH content, GSH-PX activity decreased, hOGG1 and hMTH1 mRNA expression levels decreased, hOGG1 and hMTH1 protein expression levels decreased, the difference were statistically significant (P<0.05 or P<0.01) . In 3β-HSD gene overexpression cells which were treated by DEHP, when compared with the same dose group of MCF-7 cells, MDA content decreased; SOD activity, GSH content, GSH-PX activity increased, of hOGG1 and hMTH1 mRNA expression levels increased, hOGG1 and hMTH1 protein expression levels increased, the difference were statistically significant (P<0.05 or P<0.01) .@*Conclusion@#DEHP could cause oxidative damage in MCF-7 cells, induce the changes of related genes and proteins, 3β-HSD plays an antioxidant role in the process of DEHP ox-idative damage.
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Objective To investigate the characteristics of distribution and expression profiles of plasma miRNA in childhood acute lymphocytic leukemia (cALL) patients;the association between cALL incidence risk and plasma miRNA levels;the feasibility of plasma miRNA serving as cALL diagnostic biomarker.Methods A total of 111 pairs of newly diagnosed cALL patients and patients with fractures were collected from Shenzhen Children's Hospital,China,between January 2015 and November 2016.Age and sex of the cases and controls were 1 ∶ 1 matched and LNATM miRNA microarray was performed using 4 pairs of cALL and controls selected from the sample population.The expression level of miRNA was validated by real time quantitative PCR.Conditional logistic regression analysis was applied to evaluate the association between miRNA expression levels and the incidence risk of cALL.The receiver operating characteristic curve (ROC) and reclassification analysis were conducted to assess the feasibility of miRNAs serving as biomarkers for cALL.Results A total of 204 differentially expressed miRNA were screened out and let-7f-5p,miR-5100,miR-25-3p and miR-3654 were selected for validation identified according to the inclusion criteria.The expression levels of let-7f-5p,miR-5100 and miR-25-3p in the cALL patients were significantly lower than those of the controls (P＜0.01).After adjusting for confounding factors,3 miRNAs remained significantly associated with the risk of cALL (OR and 95％CI were 0.84 (0.76-0.92),0.81 (0.73-0.90)and 0.81 (0.74-0.89),respectively.Results from both the ROC analysis and reclassification analysis showed that introduction of one or more miRNA to traditional risk factors improved the area under the curve (P＜0.05) and provided additional values to diagnosis (P＜0.01).Conclusion The expression levels of let-7f-5p,miR-5100 and miR-25-3p were significantly associated with the incidence rate of cALL,and these miRNAs might serve as promising biomarkers for cALL.
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Objective To investigate the characteristics of distribution and expression profiles of plasma miRNA in childhood acute lymphocytic leukemia (cALL) patients;the association between cALL incidence risk and plasma miRNA levels;the feasibility of plasma miRNA serving as cALL diagnostic biomarker.Methods A total of 111 pairs of newly diagnosed cALL patients and patients with fractures were collected from Shenzhen Children's Hospital,China,between January 2015 and November 2016.Age and sex of the cases and controls were 1 ∶ 1 matched and LNATM miRNA microarray was performed using 4 pairs of cALL and controls selected from the sample population.The expression level of miRNA was validated by real time quantitative PCR.Conditional logistic regression analysis was applied to evaluate the association between miRNA expression levels and the incidence risk of cALL.The receiver operating characteristic curve (ROC) and reclassification analysis were conducted to assess the feasibility of miRNAs serving as biomarkers for cALL.Results A total of 204 differentially expressed miRNA were screened out and let-7f-5p,miR-5100,miR-25-3p and miR-3654 were selected for validation identified according to the inclusion criteria.The expression levels of let-7f-5p,miR-5100 and miR-25-3p in the cALL patients were significantly lower than those of the controls (P＜0.01).After adjusting for confounding factors,3 miRNAs remained significantly associated with the risk of cALL (OR and 95％CI were 0.84 (0.76-0.92),0.81 (0.73-0.90)and 0.81 (0.74-0.89),respectively.Results from both the ROC analysis and reclassification analysis showed that introduction of one or more miRNA to traditional risk factors improved the area under the curve (P＜0.05) and provided additional values to diagnosis (P＜0.01).Conclusion The expression levels of let-7f-5p,miR-5100 and miR-25-3p were significantly associated with the incidence rate of cALL,and these miRNAs might serve as promising biomarkers for cALL.
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<p><b>OBJECTIVE</b>To investigate the potential substitution effect of hOGG1 and hMTH1 on oxidative DNA damage, based on gene-deficient cell strains models.</p><p><b>METHODS</b>hOGG1 and hMTH1 gene deficient cell strains models were established by Human embryonic lung fibroblasts (HFL) cells. After HFL cells being exposed to 100 µmol/L H₂O₂ for 12 h, HPLC-EC detecting technique and RT-PCR method were adopted to analyze the genetic expression level of 8-oxo-dG (7, 8-dihydro-8-oxoguanine).</p><p><b>RESULTS</b>The gene-deficient cell strains models of hOGG1 and hMTH1 were obtained by infecting target cells with high titer of lentivirus. The mRNA expression level of hOGG1 was 0.09 ± 0.02, 91% lower than it in normal HFL cells, which was 1.00 ± 0.04. As the same, the mRNA expression level of hMTH1 (0.41 ± 0.04) also decreased by 60% compared with it in normal HFL cells (1.02 ± 0.06). After induced by 100 µmol/L H₂O₂ for 12 h, the genetic expression level of hMTH1 in hOGG1 gene-deficient cells (1.26 ± 0.18) increased 25% compared with it in control group (1.01 ± 0.07). Meanwhile, the genetic expression level of hOGG1 in hMTH1 gene-deficient cells (1.54 ± 0.25) also increased by 52%. The DNA 8-oxo-dG levels in hOGG1 gene-deficient cells (2.48 ± 0.54) was 3.1 times compared with it in the control group (0.80 ± 0.16), the difference showed statistical significance (P < 0.01). Whereas the 8-oxo-dG levels in hMTH1 gene-deficient cells (1.84 ± 0.46) was 2.3 times of it in the control group, the difference also showed statistical significance (P < 0.01).</p><p><b>CONCLUSION</b>Based on gene-deficient HFL cells models, a synergetic substitution effect on DNA damage and repair activity by both hOGG1 and hMTH1 were firstly discovered when induced by oxidation. The substitution effect of hOGG1 were stronger than that of hMTH1.</p>
Subject(s)
Humans , Cell Line , DNA Damage , DNA Glycosylases , Genetics , DNA Repair , DNA Repair Enzymes , Genetics , Fibroblasts , Metabolism , Oxidative Stress , Genetics , Phosphoric Monoester Hydrolases , GeneticsABSTRACT
<p><b>OBJECTIVE</b>To study the potential association of DNA oxidation and DNA methylation, in vitro cultured cells were exposed to different doses of H2O2, 8-oxo-dG formation, cell DNA 5-mC contents were analyzed to explore the time- dose-response relationship of DNA oxidation and DNA methylation.</p><p><b>METHODS</b>A549 cells were exposed to different doses of H2O2, 8-oxo-dG formation and cell genomic DNA 5-mC contents were analyzed by a high-performance liquid chromatography system and high performance capillary electrophoresis (HPCE), respectively.</p><p><b>RESULTS</b>H2O2 induced the formation of 8-oxo-dG and 5-mC in different characteristics, it need at least 10 days for significant changes in the level of DNA methylation, whereas under the same conditions, changes in the level of DNA oxidation cast only 12 hours. H2O2 induced decreased levels of DNA methylation in A549 cells in a dose-dependent manner. In a certain range of time and dose, it showed a negative correlation between DNA oxidation and DNA methylation.</p><p><b>CONCLUSION</b>The study suggests that oxidative DNA could lead to reduced levels of DNA methylation, DNA oxidation may affect the regulation of cellular methylation mechanisms, in the course of chemical mutagenesis, DNA oxidation may be an earlier important molecule event than DNA methylation.</p>