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 investigate the expression level and methylation level of micro RNA-34b（miR-34b） gene in papillary thyroid carcinoma （PTC）， and to analyze the relationship between methylation and clinicopathological characters of PTC. Methods PTC tissues and tumor adjacent tissues were collected from 25 patients with PTC who underwent operation in Huai’an First People’s Hospital of Nanjing Medical University from Sep. 2008 to Oct. 2010. Expression of miR-34b gene and level of methylation in gene promoter were detected by real time PCR and methylation-specific PCR in the 2 kinds of tissues， respectively. Results The expression value of miR-34b mRNA in PTC tissues was 0.85±0.05， which was significantly lower than those of tumor adjacent tissues （1.62±0.09）， P=0.030. There were methylation in 18 （72%，18/25） PTC tissues， and 10 （40%，10/25） in tumor adjacent tissues， and the ratio of methylation was higher in PTC tissues （P=0.021）. In PTC tissues， methylation was not related to age， gender， tumor size， TNM stage， and invasion of the capsule （P＞0.05）， but was related to lymph node metastasis （P＜0.05）. Ratio of methylation in patients with lymph node metastasis was significantly higher than those of patients with no lymph node metastasis. Conclusion Methylation of miR-34b gene promoter is one of the reasons for inactivation of PTC， and it may be related to the development and metastasis of PTC， which needs to be further investigated.
ObjectiveTo observe the expression and transcription of MART-1 in human uveal melanoma cell lines 92-1, 92-2, Ocm3, Me1285, as well as the possible effect of methylation on its expression.MethodsThe cell lines 92-1, 92-2, Ocm3 and Mel285 were cultured routinely and tested for MART-1 expression at protein and mRNA level by FACS analysis, Western blot and RT-PCR respectively. Methylation status of the MART-1 promoter region in all the cell lines were checked by Southern blots of DNA digested with methylation sensitive restriction enzymes.ResultsAs observed in FACS analysis and Western blot, 92-1, 92-2 and Ocm3 were MART-1 positive cell lines while Me1285 was negative cell line. Consistent with protein analysis, 92-1 and Ocm3 cell lines showed MART-1 specific PCR products and there was no product in Me1285 cell line in RT-PCR. The MART-1 positive cell lines, 92-1, 92-2, and Ocm3 show methylation at the MspI/HpaⅡ site, and the NruⅠ sites of all positive cell lines are not methylated. The MART-1 negative cell line Mel285 shows hypermethylation at the NruⅠsite and the MspⅠ/HpaⅡ site is not methylated.ConclusionsMART-1 could be expressed in human uveal melanoma cell lines 92-1, 92-2 and Ocm3. The change of methylation status of MART-1 promoter may correlate with the transcription of MART-1.
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.
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 role of DNA methylation in the pathogenesis of cholangiocarcinoma and its progress as a therapeutic target for cholangiocarcinoma.MethodThe relevant literatures at home and abroad in recent years about the DNA methylation and cholangiocarcinoma were reviewed.ResultsMethylation is a frequent event in cholangiocarcinoma and effect the occurrence and development of cholangiocarcinogenesis. DNA methylation inhibitors reactivate tumor suppressor genes.ConclusionsDNA methylation is closely related to the cholangiocarcinogenesis. Despite there is no effective clinical therapeutics and diagnosis at present, with further study, DNA methylation is expected to be one of the new target to treatment and diagnosis this disease.
Lung cancer is the most common malignant tumor in the world and the leading cause of cancer-related death. Due to the lack of effective early diagnosis methods, the prognosis of lung cancer is poor, but compared with advanced lung cancer, the survival rate of early lung cancer is greatly improved. Therefore, early diagnosis of lung cancer is crucial. As a major epigenetic modification, DNA methylation plays an important role in the development of lung cancer. A large number of studies have shown that detection of tumor suppressor gene methylation is an ideal early diagnosis method for lung cancer. With the continuous improvement of detection technology, methylation detection of multiple genes can be achieved. And it is found that multi-gene methylation combined detection of tissue samples obtained by minimally invasive operation such as puncture of diseased tissue and puncture of lymph node tissue, as well as the noninvasive samples such as peripheral blood, bronchoalveolar lavage fluid and sputum have higher detection rate and higher sensitivity and specificity than single gene methylation. It is an ideal method for early diagnosis of lung cancer.
ObjectiveTo summarize the current research status of the relationship between DNA methylation and liver regeneration.MethodThe related literatures at home and abroad were searched to review the studies on relationships between the methylation level of liver cells, regulation of gene expression, and methylation related proteins and liver regeneration.ResultsThe DNA methylation was an important epigenetic regulation method in vivo and its role in the liver regeneration had been paid more and more attentions in recent years. The existing studies had found the epigenetic phenomena during the liver regeneration such as the genomic hypomethylation, methylation changes of related proliferating genes and DNA methyltransferase and UHRF1 regulation of the liver regeneration.ConclusionsThere are many relationships between DNA methylation and liver regeneration. Regulation of liver regeneration from DNA methylation level is expected to become a reality in the near future.
Objective To investigate the expression of the histone deacetylases 1( HDAC1) and the level of whole histone acetylation and methylation in lung T cells of asthmatic rats, and investigate their role in the pathogenesis of asthma.Methods Sixteen wistar rats were randomly divided into a control group and an asthma group( n =8 in each group) . The rats was sensitized with ovalbumin( OVA) and challenged with aerosol OVA to establish asthma model. The asthmatic ratmodel was confirmed by measurement of pulmonary function, histochemical staining, HE staining, and the levels of interleukin-4 ( IL-4 ) , interferon-gamma ( IFN-γ) and immunoglobulin E( IgE) in serum and bronchoalveolar lavage fluid ( BALF) . T cells were isolated fromrat lungs and the purity was identified. The expression of the HDAC1, the level of whole histone H3 and H4 acetylation, and whole H3K9 dimethylation were analyzed by Western blot in lung T cells. Results Compared with the control group, the protein expression of HDAC1 was significantly lower( 0. 465±0. 087 vs 0. 790 ±0. 076, P lt;0. 05) in lung T cells of the asthma group. No significant differences werefound in regard to the level of whole histone H3 and H4 acetylation and whole H3K9 dimethylation betweenthe two groups. Conclusions HDAC1 in lung T cells may be involved in the pathogenesis of asthma.Histone modification by HDAC1 may be a specific eventwith gene transcription which may not be associated with asthma.