Objective To investigate the effects of DNA methyltransferase inhibitor (DNMTi) and histone deacetylase inhibitor (HDCAi) on expression of E-cadherin gene and invasiveness of cholangiocarcinoma cell. Methods According to different treatment, the QBC939 cells were divided into four groups: blank control group, hydralazine group, valproic acid group and hydralazine and valproic acid combined group. After 48 h, the expression of E-cadherin was evaluated by reverse transcription-PCR (RT-PCR), mehtylation specific PCR (MSP) and Western blot, the invasiveness of QBC939 cells was evaluated by Transwell method. Results There was no expression of E-cadherin mRNA and protien in blank control group and valproic acid group. The expressions of E-cadherin mRNA and protien in hydralazine and valproic acid combined group were higher than those in hydralazine group ( P ＜ 0.01), while the invasiveness of QBC939 cells of hydralazine and valproic acid combined group was much lower than that of blank control group, hydralazine group and valproic acid group ( P ＜ 0.01). Conclusion DNMTi and HDACi can synergistically re-express E-cadherin gene and weaken the invasiveness of QBC939 cell, which plays an important part in treatment of cholangiocarcinoma.
ObjectiveTo determine the level of CDH1 gene promoter hypermethylation in human gastric carcinoma by establishing MS-PCR method, and analyze retrospectively the possible statistical relationship between CDH1 gene promoter hypermethylation in human gastric carcinoma and HP infection, tumor differentiation, invasion, lymph nodal and distant metastasis, respectively. MethodsThe bisulfite conversion MS-PCR method was adopted to examine the level of CDH1 gene promoter hypermethylation in 40 cases of human gastric carcinoma tissue collected between January 2008 and December 2009. The statistical relationship between CDH1 gene promoter hypermethylation in human gastric carcinoma and HP infection, tumor differentiation, invasion, lymph nodal and distant metastasis were examined respectively with SPSS statistical tools. ResultsThe positive rate of CDH1 gene promoter hypermethylation in gastric carcinomas (67.5%) was higher than that in paired normal gastric mucosae (12.5%), and the difference was significant (P<0.05). In gastric carcinomas, the positive rate of CDH1 gene promoter hypermethylation in well differentiated or moderately differentiated groups (22.2%) was lower than that in poorly differentiated groups (80.6%), and the difference was significant (P<0.05). The positive rate of CDH1 gene promoter hypermethylation in HP positive groups (78.1%) was higher than that in HP negative groups (25.0%), and the difference was significant (P<0.05). ConclusionCDH1 gene promoter hypermethylation may play an important role in the process of tumor carcinogenesis in gastric carcinomas. Meanwhile, the CDH1 gene promoter hypermethylation may lead to poor differentiation in gastric carcinomas. CDH1 gene promoter hypermethylation is related to HP infection in the original gastric carcinomas, which shows that HP may get involved in the process of tumor suppressor gene methylation/inactivation and tumor development process.
ObjectiveTo investigate the difference of DNA methylation before and after bariatric surgery.MethodThe relevant literatures of the research on the changes of DNA methylation level and gene expression regulation in blood and tissues before and after bariatric surgery were retrieved and reviewed.ResultsDNA methylation was an important method of epigenetic regulation in organisms and its role in bariatric surgery had been paid more and more attention in recent years. Existing studies had found that there were changes of DNA methylation in blood and tissues before and after bariatric surgery. The degree of methylation varies with different follow-up time after bariatric surgery and the same gene had different degrees of methylation in different tissues, and some even had the opposite results.ConclusionsDNA methylation levels before and after bariatric surgery are different in different tissues. And studies with larger sample size and longer follow-up time are needed, to further reveal relationship among DNA methylation, obesity, and bariatric surgery.
Objective To examine the expression of promoter CpG island methylation of Notch1 gene and explore the variable sites for DNA methylation in lung CD4 + T cells of asthmatic rat models.Methods An ovalbumin ( OVA) sensitized- challenged asthmatic rat model was established. Total T cells were isolated and CD4 + T lymphocytes were purified using magnetic beads. Twenty Wistar rats were randomly divided into a control group and an asthma group ( n = 10 in each group) . CD4 + T cells were isolated by immunomagnetic beads and identified by flow cytometry ( FCM) . Realtime PCR was employed to examine the mRNA expression of Notch1 gene in lung CD4 + T cells and the methylation level of Notch1 gene was examined by methylation-specific PCR. Results The mRNA expression of Notch1 in lung CD4 + T cells of the asthma group was 2. 254 ±0. 403 times as much as that of the control group. The total methylation level of asthma group was lower than that of the control group ( 0. 150 ±0. 108 vs. 0. 300 ±0. 667, P lt;0. 01) . Conclusion Promoter demethylation is one of the major mechanisms of Notch1 gene up-regulation in pathogenesis of asthma.
The regulation of epigenetics on bone marrow mesenchymal stem cells (BMSCs) has been a research hot spot in medical area. This paper mainly summarizes the progress of the regulation of DNA methylation, histone acetylation, small interfering RNA (siRNA) induced gene silence and microRNA (miRNA) on BMSCs. Our analysis shows that the regulation of epigenetics on BMSCs plays a significant role in the repair of bone tissue, nervous tissue and cardiac muscle.
Retinoblastoma (RB) is a common intraocular tumor in children, often leading to blindness or disability, and its pathogenesis involves genetic and epigenetic regulation. Epigenetics regulates gene expression through mechanisms such as DNA methylation and histone modification without altering the DNA sequence, and the imbalance of its homeostasis is considered a crucial factor in the development and progression of RB. Therapeutic strategies targeting these abnormal modifications offer new potential treatment avenues for RB. Although current research has highlighted the importance of epigenetics in RB, the specific mechanisms of action, the relationship with genetic bases, and the development of targeted drugs remain largely unknown. Therefore, further in-depth research into the epigenetic mechanisms of RB is of great significance for elucidating its carcinogenic mechanisms, identifying effective therapeutic targets, and developing new drugs.
ObjectiveTo explore the relationship between aberrant promoter CpG islands methylation status of E-cadherin gene and hepatocarcinogenesis, and to assess its significance in clinical early diagnosis of hepatocellular carcinoma (HCC). MethodsSurgically resected specimens, among which cancerous and corresponding noncancerous liver tissues from 34 HCC patients, 10 liver cirrhosis from patients without HCC and normal liver tissues from 4 accidental deaths, were collected in West China Hospital. Breast cancer cell line MDA-MB-435 with promoter CpG islands hypermethylation of E-cadherin as positive control was gained from the Cell Bank of Chinese Academy of Sciences in Shanghai. The methylation status of promoter CpG island of E-cadherin gene was detected by nested methylationspecific polymerase chain reaction (nested-MSP). ResultsE-cadherin gene promoter CpG islands hypermethylation was found in 61.76% (21/34) of cancerous tissues, in 29.41% (10/34) of noncancereous tissues from the 34 HCC patients and in 50.00% (5/10) liver cirrhosis from patients without HCC. None of the 4 normal liver samples were detected E-cadherin mehylation positive. Moreover, the methylation of E-cadherin gene was significantly more frequent in 34 cancerous than that in corresponding noncancerous liver tissues (Plt;0.05), which had no significant difference between the 10 cirrhotic samples and cancerous or non-cancerous liver tissues (Pgt;0.05). In 34 cancerous samples, with the combination of both biomarkers of E-cadherin methylation and AFP400 (serum AFP level at a cutoff of 400 μg/L), the diagnostic sensitivity of HCC increased to 82.35%. ConclusionsThe aberrant promoter methylation of E-cadherin gene may play a vital role in the development and progression of HCC. Moreover, it might be an early event in hepatocarcinogensis. It is of high value to make further study to confirm the significance of E-cadherin gene methylation in clinical diagnosis and therapy.
Objective To investigate the role of DNA methylation on regulation of cell apoptosis and proliferation in ischemia-reperfusion of small intestine. Methods Thirty-five male Wistar rats were randomly divided into normal group， sham operation group， and ischemia-reperfusion group. The apoptotic cell was assessed by TUNEL and electron microscopy and the expression of Ki-67 was examined by immunohistochemistry in the small intestinal parts （villi epithe-lium， crypt epithelium， and lamina propria mucosa of small intestine）. The DNA methylation was detected by DNA histo-endonuclease-linked detection of methylated DNA sites. Results ①The apoptotic positive cells increased at 3 h， 6 h，and 12 h after ischemia-reperfusion in the villi epithelium， crypt epithelium， and lamina propria mucosa of small intestine as compared with the normal group and sham operation group （P＜0.01）；Moreover， the apoptotic cells in the lamina propria mucosa of small intestine were identified as T cells by electron microscopy. ②The expressions of Ki-67 markedly increased at 3 h， 6 h， 12 h， and 24 h after ischemia-reperfusion in the villi epithelium cells as compared with the normal group and sham operation group （P＜0.01）. ③The weak expression of DNA methylation was found in the villi epith-elium and crypt epithelium in the normal group and sham operation group， the b expression was examined in the crypt epithelium cells nearby stem cell site in the ischemia-reperfusion of small intestine， the change of expression was gradually weak from crypt epithelium to villi epithelium. Conclusion This initial results indicate that the DNA methyl-ation in the ischemia-reperfusion of small intestine might regulate cell apoptosis and proliferation.
Diabetic retinopathy (DR) is one of the most common microvascular complications of diabetes, characterized by high blindness rates and a severe impact on patients' quality of life. Despite adequate glycemic control, some patients exhibit persistent progression of retinal microvascular damage, known as the "metabolic memory" phenomenon. Studies have revealed that the essence of this phenomenon is the sustained expression of epigenetic reprogramming induced by metabolic stress, in which abnormal mitochondrial DNA (mtDNA) methylation plays a pivotal role. Metabolic abnormalities such as hyperglycemia, hyperhomocysteinemia, and hyperlipidemia can alter mtDNA methylation patterns, triggering cascading pathological processes including oxidative stress, chronic inflammation, and neurovascular network disorders, remodeling mitochondrial energy metabolism, and promoting the evolution of DR from subclinical compensatory stage to irreversible structural damage. Abnormal mtDNA methylation serves as a hallmark of metabolic memory and a core driver of microvascular lesions, providing an important theoretical basis for in-depth analysis of metabolic memory mechanisms and exploration of DR intervention strategies. Current research needs to further elucidate its role in DR. Future efforts require integration of multi-dimensional epigenetic biomarkers, precise intervention approaches, and clinical translational research to advance the early diagnosis and individualized treatment of DR.
ObjectiveRecent advancements in the researches on cholangiocarcinoma (CC) related genes methylation in CC were reviewed and the clinical significances of aberrant DNA methylation for the diagnosis and treatment of CC were discussed. MethodsRelevant literatures about the relation between CC-related genes methylation and CC published recently were collected and reviewed. ResultsThe genesis of CC resulted from abnormal expressions of many genes. Many researches had shown that the abnormal methylation of CC-related genes had a close relation with CC. Epigenetic alteration had been acknowledged as an important mechanism contributing to early CC carcinogenesis. ConclusionsAbnormal methylation of CC-related genes is related with CC. The detection of CC-related genes methylation might provide new specific biomarkers for early noninvasive diagnosis of this disease. Using epigenetic agents such as azacytidine to modulate the activities of DNA methyltransferase and reverse the methylation status of CC-related gene might be an attractive strategy for future treatment of CC, which could be combined with conventional therapies.