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Objective To investigate the effects of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on the apoptosis of A549/DDP cells and the expression of hMLH1 gene.Methods A549/DDP cells were treated with 5-Aza-CdR at 0.5,5,50 μmol/L.The growth curve of A549/DDP cells was investigated by MTT assay.The methylation status of hMLH1 gene was detected by methylation specific PCR (MSP).The expression of hMLH1 mRNA was evaluated by FQ-PCR.The apoptosis rate of A549/DDP cells was analyzed by flow cytometry.Results A549/DDP cells treated with 5-Aza-CdR showed a slow growth in comparison with the control cells,and the growth rates were decreased with the increasing of 5-Aza-CdR concentration.The apoptosis rate after treatment was higher than that before treatment in A549/DDP cells (P ＜ 0.05),and had a positive correlation with 5-Aza-CdR dose (P ＜ 0.001).hMLH1 mRNA expression level was increased in a 5-Aza-CdR concentration dependent manner (P ＜ 0.05).hMLH1 promoter in A549/DDP cells was methylated and hMLH1 mRNA was negatively expressed before treatment,but the mRNA was positively expressed after treatment with 5-Aza-CdR.Conclusions 5-Aza-2'-CdR can induce apoptosis of A549/DDP cells by inducing demethylation of hMLH1 promoter and thereby enhancing hMLH1 gene expression and its tumor suppressor function.
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Objective To investigate the Reprimo and hMLH1 gene promoter methylation detection value in the diagnosis of early gastric cancer.Methods Chose patints in Shaanxi Provincial People’s Hospital from September 2013 to April 2014,50 cases of patients with chronic atrophicgastritis with intestinal metaplasia,50 cases of patients with gastricmucosal atypical hyperplasia,50 patients with gastric cancer,endoscopic gastric biopsy samples,and 30 cases of normal gastric mucosa biopsy tissues as control group.Analysis abnormal expression in Reprimo gene and hMLH1 genes promoter methylation,compared the differences.between groups of patients.Results The patients with gastric mucosatissues Reprimo and hMLH1 genes promoter methylation positive rate was significantly higher than that of normal group,the difference wasstatistically signifi-cant (P<0.05).Reprimo gene promoter methylation were:patients with chronic atrophic gastritis with intestinal metaplasia 28% (χ2 =10.18,P < 0.05).Patients with gastric mucosalatypical hyperplasia 56% (χ2 = 25.84,P < 0.05)and patients with gastric cancer 62% (χ2 = 30.36,P < 0.05).hMLH1 gene promoter methylation were:patients with chronic atrophic gastritis with intestinal metaplasia 20% (χ2 =4.39,P <0.05),patients with gastric mucosal atypical hyperplasia 44% (χ2 =15.13,P <0.05)and patients with gastric cancer 48% (χ2 = 17.41,P <0.05),high specificity of detection.Conclusion Reprimo and hMLH1 gene’s detect value in the diagnosis of early gastric cancer is very high,high specificity,it is an effec-tive way of diagnosis,treatment in clinical diagnosis of patients with broad prospects.
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Objective: To investigate the aberrant methylation status of hMLH1 (human mutL homologue 1) gene in PTC (papillary thyroid carcinoma) tissues, and its correlations with the aberrant methylation of NIS (sodium iodide symporter) and TSHR (thyroid-stimulating hormone receptor) genes. Methods: qMSP (quantitative methylation-specific PCR) was carried out to detect the promoter methylation status of hMLH1, NIS and TSHR genes in PTC tissues and adjacent normal thyroid tissues from 152 patinets with PTC. The correlation between the clinicopathologic characteristics and the promoter methylation status of hMLH1 gene was analyzed. The relationships among the methylation status of hMLH1, NIS and TSHR genes and their independent or synergistic effects on the progression of PTC were investigated. Results: The promoter methylation rate of hMLH1 gene in PTC tissues (37.5%) was significantly higher than that in the adjacent normal thyroid tissues (5.3%) (P 0.05). There was a weak correlation among aberran promoter methylation of hMLH1, NIS and TSHR genes (r 0.05). Conclusion: The aberrant methylation of hMLH1 gene promoter in PTC tissues might be associated with the progression of the tumor. There exists no correlation among the aberrant methylation of hMLH1, NIS and TSHR genes, and their independent or synergistic effect also may not be associated with the progression of PTC. Copyright © 2013 by TUMOR.
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Purpose:To study the etiological role of Val384Asp in hMLH1 gene in gastric and esophageal cancer.Methods:Genomic DNA were extracted from peripheral blood and were subjected to PCR SSCP and DNA sequencing to screen Val384Asp in hMLH1 gene in 79 gastric and 76 esophageal cancer patients, and in 79 and 76 first degree relatives of gastric and esophageal cancer patients respectively, and in 100 healthy persons. Results:There is a significant difference in the frequency of Val384Asp between gastric cancer patients with family history and healthy controls ( P 0.05). Conclusions:The alleles frequency of Val384Asp in Chinese is 3%. It may partly play an etiological role in some of the stomach cancer patients.