Objective To study the differential expression profiling of the transcripts modified by m5C methylation in a rat model of N-methyl-D-aspartate (NMDA)-induced retinal excitotoxicity. MethodsA total of 65 Sprague Dawley male rats aged 7-8 weeks were randomly divided into two groups: normal control group and NMDA group. The right eye (model eye) of rats in the NMDA group were injected with 50.0 mmol/L of NMDA 3 μl in the vitreous cavity, while in the normal control group, equal volume of normal saline was injected into the vitreous cavity. After 1 week of the injection, the optic nerve conduction function of rats was detected by visual evoked potential. The whole structure of rat retina was observed by hematoxylin-eosin staining, and the thickness of each retinal layer and the number of retinal ganglion cell layer were detected. The number of β3 tubulin immunofluorescence positive cells was detected by immunofluorescence staining on retinal stretched preparation. Total RNA was extracted from the retinas of normal control group and NMDA group, and high-throughput m5C modified RNA was sequenced, and bioinformatics analysis was performed. The relative expression levels of SLFN3, PLXNB3, CD36 and HIC2 mRNA in retina were detected by real-time quantitative polymerase chain reaction. The comparison between the two groups was performed using an unpaired t test. ResultsThe P1 latency of control group and NMDA group were (117.86±6.48) and (148.46±3.78) ms, and the amplitudes were (42.57±2.41) and (8.68±0.63) μV, respectively. Compared with the normal control group, the latency period was prolonged and the amplitude was significantly decreased in the NMDA group, with statistical significance (P＜0.001). In normal control group, retinal ganglion cells (RGC) were uniformly arranged with large round nuclei. In NMDA group, the volume of retinal RGC was atrophied and the number of RGC was reduced. The total retinal thickness in the control group and NMDA group was (207.51±12.76) μm and (187.51±12.54) μm, respectively. The number of β3 tubulin positive cells was 79.86±6.56 and 29.36±2.16, respectively. Compared with normal control group, the total retinal thickness and the number of β3 tubulin positive cells in NMDA group were decreased, with statistical significance (P＜0.001). Compared with the control group, 576 differentially expressed m5C mRNA were screened in the NMDA group, among which 230 up-regulated and 346 down-regulated genes were detected, respectively. The results of biological information analysis showed that compared with the control group, the upregulated m5C mRNA in the NMDA group was mainly involved in biological processes such as perception and cell-cell adhesion, and was mainly concentrated in the cytokine-cytokine receptor interaction and neural active ligand-receptor interaction pathway. The biological processes in which down-regulated m5C mRNA was mainly involved in biological processes such as G-protein-coupled receptor signaling pathway and cell communication, which were mainly concentrated in primary immune deficiency pathway and neural active ligand-receptor interaction pathway. Real-time quantitative polymerase chain reaction detection results showed that compared with the normal control group, the relative expression levels of SLFN3 and PLXNB3 mRNA in the retina of rats in NMDA group were significantly increased, while the relative expression levels of CD36 and HIC2 mRNA were significantly decreased, with statistical significance (P＜0.05). ConclusionIn NMDA induced retinal excitatory toxicity rat models, m5C modified retinal transcriptome showed abnormal expression.
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.
ObjectiveTo explore the clinical significance of promoter hypermethylation of O6-methylguanine-DNA methyltransferase (MGMT) in cholangiocarcinoma. MethodsPromoter methylation status of MGMT gene and expression of MGMT protein were detected in cholangiocarcinoma by methylationspecific PCR and immunohistochemical staining, respectively. ResultsAberrant methylation of MGMT gene was detected in 17 patients (47.2%). Twentyone cases showed negative immunoreactivities. Of 21 patients with negative MGMT expression, 14 patients had aberrant methylation of MGMT gene. In 15 patients with positive MGMT expression, aberrant methylation of MGMT gene was only found in three cases. There was a negative correlation between promoter methylation status of MGMT gene and the expression of MGMT protein (rs=-0.816, Plt;0.05). Promoter methylation status of MGMT gene was related to depth of invasion, degree of differentiation, and TNM stage (Plt;0.05), but not to age of patient, gender, pathological type, and lymph node metastasis (Pgt;0.05). ConclusionsHypermethylation of MGMT promoter is a frequency molecular event in cholangiocarcinoma and may be involved in carcinogenesis. Methylation status of MGMT gene may be used to evaluate malignant degree of cholangiocarcinoma.
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.
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 systematically review the effectiveness and safety of demethylation agents in patients with myelodysplastic syndrome. MethodsRandomized controlled trials (RCTs) about demethylation agents in treating myelodysplastic syndrome was electronically searched in PubMed, EMbase, The Cochrane Library (Issue 3, 2013), Web of Science, CNKI, VIP, WanFang Data and CBM from inception to March 2013. Two reviewers independently screened literature according to the inclusion and exclusion criteria, extracted data, and assessed methodological quality of the included studies. Meta-analysis was performed using RevMan 5.1 software. ResultsA total of 4 studies involving 816 patients were finally included. The results of meta-analysis showed that:for patients with myelodysplastic syndrome at middle/advanced stage, compared with the best supportive treatment plan, demethylation agents improved complete remission (CR) (OR=19.14, 95%CI 5.33 to 68.7, P < 0.000 01), partial remission (PR) (OR=20.63, 95%CI 5.76 to 73.93, P < 0.000 01), hematological improvement (HI) (OR=3.58, 95%CI 2.40 to 5.34, P < 0.000 01), and the incidences of Grade Ⅲ or Ⅳ neutropenia (OR=3.82, 95%CI 2.67 to 5.47, P < 0.000 01), Grade Ⅲ or Ⅳ thrombocytopenia (OR=3.98, 95%CI 2.55 to 6.23, P < 0.000 01), and mortalities (OR=0.52, 95%CI 0.35 to 0.77, P < 0.000 01), all with significant differences; and part of patients suffered from Grade Ⅲ or Ⅳ thrombocytopenia and tolerable adverse reaction caused by non-hematologic change. ConclusionCurrent evidence suggests that demethylation agents in treating myelodysplastic syndrome have apparently curative effects. Besides, it could prolong the time of turning into acute myelocytic leukemia, reduce mortalities, and improve patients' quality of life.
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 summarize mechanism of DNA methylation and histone methylation in liver fibrosis.MethodThe literatures on the DNA methylation and histone methylation during the liver fibrosis were reviewed and analyzed.ResultsThe DNA methylation and histone methylation were the important components of epigenetics. The up-regulation or down-regulation of genes during the liver fibrosis leaded to the activation or inactivation of the subsequent pathways. For example, the PTEN, SEPT9, Smad7, etc. were hypermethylated and the expressions were decreased in the liver fibrosis. The Spp1 was hypomethylated and the expression was increased in the liver fibrosis.ConclusionsMethylation affects expression of genes by altering epigenetics of genes. Systematic and in-depth study of role and mechanism of methylation in liver diseases provides a new direction and locations for some target treatments for liver disease.
Objective To investigate the possible mechanism of arsenic trioxide (As2O3) inducing P16 gene demethylation and transcription regulation in the retinoblastoma (RB) Cell Line Y79． Methods The induced growth inhibition of Y79 cell was assayed by MTT; The DNA content of Y79 cell was analyzed by flow cytometry after being exposed to As2O3; the methylation status of the P16 gene in Y79 cell line before and after treatment with As2O3 was detected by the nestedmethylation specific PCR and DNA sequencing; the mRNA of P16,DNA methyltransferases (DNMT3A and 3B)gene were determined by RT-PCR． Results As2O3 was able to inhibit the growth of Y79 cell and increase the cell number in G0-G1 phase；P16 gene was not expressed in Y79 cell line and As2O3 can induce itrsquo;s mRNA expression；after 48 hour disposal of As2O3，the methylation levelof P16 gene was apparently attenuated in Y79 cell line,the expression of DNMT3A and DNMT3B was obviously down-regulated． Conclusions P16 gene is the hypermethylation in the retinoblastoma cell line Y79, and As2O3 can inhibite the methylation of P16 gene and upregulate the expression of p16 gene mRNA which inhibits the proliferation of Y79 cell by inducing the G0-G1 arrest, by inhibiting the expression of DNA methyltransferases.