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Using the concepts and methods of epigenetics and metabolomics, to investigate the overall action molecular mechanism of Chrysanthemi indici C (CIC), the anti-hepatitis B virus (HBV) active extracts from Flos chrysanthemi indici. The inhibitory effects of CIC on proliferation and hepatitis B surface antigen (HBsAg), hepatitis B envelope antigen (HBeAg) and HBV-DNA of HepG2.2.15 cells were detected by CCK-8 and antigen kit. The DNA methyltransferases (DNMTs)/ten-eleven-translocation-2 (TET2) equilibrium was detected by ELISA. Illumina 850K methylation chip, pyrosequencing and qPCR were used to determine the action pathway and target of CIC by GO and KEGG analysis. Cell metabolites were extracted with 80% methanol, and the changes of differential metabolites, differential metabolic pathways and cell microenvironment were detected by LC-MS and other metabolomics methods. The results showed that CIC could inhibit the proliferation, HBsAg, HBeAg and HBV-DNA of HepG2.2.15 cells obviously, down-regulate DNA methyltransferase 1 (DNMT1), DNA methyltransferase 3a (DNMT3a) and DNA methyltransferase 3b (DNMT3b), up-regulate TET2, and restore the balance of DNMTs/TET2. The action targets of CIC were phospholipase C gamma 2 (PLCG2), phosphoinositide-3-kinase regulatory subunit 3 (PIK3R3), 1-acylglycerol-3-phosphate O-acyltransferase 2 (AGPAT2), 5-hydroxytryptamine receptor 2B (HTR2B), nerve growth factor (NGF), mainly involved in lipid metabolism, inflammation mediated regulation of transient receptor potential (TRP), phospholipase D signaling and advanced glycation end product-receptor for AGE (AGE-RAGE) signaling in diabetic complications pathways. CIC could significantly affect fatty acid metabolism and had great influence on phenolic acid, alkaloid and lipid metabolites in cell microenvironment. These results suggest that the action mechanism of CIC may be the synergistic action of multiple pathways and multiple targets, including related inflammatory pathways, immune pathways and lipid metabolism, through regulating epigenetic expression balance and restoring the balance of cell microenvironment.
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Objective@#To investigate the effects of Paraquat on neural stem cell proliferation in vitro and explore the its mechanism based on DNA methylation pathway.@*Methods@#Nestin, β-tubulin III, and glial fibrillary acidic protein (GFAP) were detected by indirect immunofluorescence assay to evaluate self renewal and differentiation potentia of ReNcell CX human neural stem. The cells were treated with terminal concentrations of 0, 5, 25, 50, and 100μmol/L PQ for 24 hours, and the cells were induced by 50 μmol/L PQ for different time (6, 12, 24, 48 h). Cell viability was determined by MTT assay. The proliferation of neural stem cells was evaluated using Sox2/Brdu and Nestin/Brdu double immunofluorescence staining. The global DNA methylation level was assayed by MethyflashTM methylated DNA Quantification kit. The expression levels of Dnmts mRNA and protein were analyzed by quantitative reverse transcription polymerase chain reaction(qRT-PCR) and Western blot, respectively.@*Results@#Immunofluorescence showed that nestin was primarily expressed in proliferative neural stem cell and peotein biomarkers (β-tubulin III, GFAP) for neuron and astrocyte were expressed in differentiated cells. MTT assay showed PQ induced cell survival rate decrease in a time and dose dependent manner. Double immunfluorescence staining of cells showed colocalization of Sox2 and Brdu. The percentage of Brdu/Sox2 positive cells was significantly lower in the PQ-exposed (25, 50, 100μmol/L PQ treatment) groups compared to control (P<0.05); Meanwhile, The percentage of Brdu/Nestin positive cells was also significantly lower in the PQ-exposed(50,100μmol/L PQ treatment) groups compared to control (P<0.05). The results of global DNA methylation revealed a significant decrease in PQ-exposed groups (P<0.05). Western blot showed that compared with control group, the protein and mRNA levels of Dnmt1, Dnmt3a in PQ-exposed group were significantly decreased (P<0.05), but there was a significant increase in expression level of Dnmt3b in 50, 100 μmol/L PQ-treated group(P<0.05).@*Conclusion@#Paraquat could inhibite the proliferation of human neural stem cells through reducing the level of DNA methylation reaction by suppressing the protein expression and transcription of DNA methylated transferase(Dnmts).
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Breast cancer is now the most common malignant tumor in Chinese women. Approximately 70% of breast cancers express estrogen receptor (ER) which plays a critical role in the development of breast cancer. Endocrine therapy has become one of the most effective treatments for ER-positive breast cancer. At present, the endocrine therapy drugs are mainly divided into three categories: selective ER modulators, selective ER down-regulators and aromatase inhibitors. The adjuvant endocrine therapy with these drugs can reduce the risk of breast cancer recurrence by nearly 40%. However, the resistance of tumor cells to endocrine therapy is a major factor limiting the success of breast cancer treatment. The known mechanisms of endocrine therapy resistance include the concentration of estrogen increased in tumor microenvironment, ER gene mutation, up-regulation of multiple molecular signal pathway, and epigenetic mechanisms. Overcoming endocrine therapy resistance is essential for further improving the benefit rate of endocrine therapy. In this review, the progresses of epigenetic mechanisms (including DNA methylation and histone modification) and epigenetic drugs (including DNAmethyltransferases inhibitors and histone deacetylases inhibitors) of endocrine therapy resistance in ER-positive breast cancer are introduced, in order to further understand the mechanism and therapeutics of endocrine therapy resistance in breast cancer.
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The epigenetic changes of clear cell renal cell carcinoma(ccRCC )are considered to be the main molecular mechanisms of its pathogenesis ,including DNA methylation ,histone modification ,microRNA change ,and so on.DNA methyltransferases(DNMTs)catalyze the occurrence of DNA methylation.DNA methylation changes are mani-fested in the overall low methylation of the genome and the high methylation of specific sites ,which were involved in the de-velopment of ccRCC by affecting the expression of tumor suppressor genes.Due to histone-modified enzyme involvement ,histone modification is shown as possible genetic reversal.MicroRNA plays an important role in the abnormal expression of ccRCC genes.With the studies of epigenetic mechanism and molecular pathology ,it is important to explore the mechanisms and to seek effective early diagnosis ,treatment and prognosis intervention of ccRCC.
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Objective@#To investigate the correlation between CpG islands methylation statuses of TGF-β3, Dnmts and their expression during TCDD-induced mouse embryonic palatal development.@*Methods@#Eithtteen pregnant C57BL/6J mice were randomly divided into 2 groups: the control group(n=9) and TCDD-exposure group(n=9). At gestation day 10.5(GD10.5), the mice in TCDD-group were orally administrated with TCDD 28 μg/kg, while the mice in the control group received equivalent corn oil. The pregnant mice were sacrificed at GD13.5, GD14.5, GD15.5, fetal palates were collected. CpG island methylation statuses were analysed by methylation specific polymerase chain reaction(MSP). IBM SPSS 20.0 software was applied for statistical analysis. Kolmogorov-Smirnov test was used for normal distribution check, and the distributions were normal. Independent t-test was carried out between two groups. P<0.05 was considered statistically significant.@*Results@#CpG island in promoter region of gene TGF-β3 were all at low methylation level at all GDs of both groups, there were no differences at same GD between two groups [GD13.5: (8.6±0.8)% vs (8.7±0.8)%, P>0.05; GD14.5: (11.5±1.4)%vs (11.7±1.0)%, P>0.05; GD15.5: (12.0±0.7)% vs (12.1±0.5)%, P>0.05]. CpG island in promoter region of gene Dnmt1 were all highly methylated with no differences showed at same GD between two groups [GD13.5: (73.9±1.1)%vs (72.6±0.8)%, P>0.05; GD14.5: (70.8±1.7)% vs (70.7±1.0)%, P>0.05; GD15.5: (69.4±2.2)% vs (69.7±0.5)%, P>0.05]. The methylation level of CpG island 1 in promoter region of gene Dnmt3a in TCDD group was higher than that in control group at GD13.5 and GD15.5 [(21.9±1.1)% vs (8.1±0.6)%, P<0.01, (43.4±0.4)% vs(32.9±0.7)%, P<0.01], while lower at GD14.5[(33.2±0.5)% vs (42.9±0.3)%, P<0.01]. The methylation level of CpG island 2 in promoter region of gene Dnmt3a in control group was higher than that in TCDD group at all GDs [GD13.5: (82.0±0.7)% vs (32.3±0.6)%, P<0.01; GD14.5: (62.7±1.0)%vs (25.5±1.4)%, P<0.01; GD15.5: (47.2±0.4)% vs (30.3±1.4)%, P<0.01].@*Conclusions@#Low methylation level of CpG island 2 which is close to the first exon in promoter region of gene Dnm3a may be the cause of highly expressed Dnmt3a mRNA at GD13.5 during mice palatogenesis induced by TCDD, thus the global DNA methylation is extremely high to induce cleft palate. TCDD-treatment doesn′t influence the CpG methylation statuses in promoter region of TGF-β3 and Dnmt1.
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Objective To observe the effect of hippocampal DNA methyltransferases (DNMTs)on neonatal cognitive impairments induced by sevoflurance exposure.Methods Sixty-four 7-day old male Sprague-Dawley rats were randomly divided into the following four groups (n =1 6):control group (group C),sevoflurane group (group S),sevoflurane+NaCl group (group SN),and sevoflurane+5-AZA group (group SA).Sevoflurane animals received 3% sevoflurane plus 30% oxy-gen for 2 hours daily for 3 consecutive days,and rats in group C were placed into the same container, which contained 30% oxygen only.Animals in group SA were intracerebroventricularly injected with 5-AZA (1 mg/kg),while group SN same volume of NaCl one hour before sevoflurane exposure. Open field and Morris water maze were given the four weeks after anesthesia (n =8).Rats without any behavior tests from each group (n =8)were euthanized 4 weeks after the treatment and the hip-pocampus was harvested.Quantitative real-time PCR and Western blot were used to detect the mRNA and protein levels of DNMT1,DNMT3a and DNMT3b.Results In the open field test,no significant difference was observed in the distance travelled and the time spent in the center of the arena.Com-pared with the group C,group S showed an increase in the latency,decreased time spent in the target quadrant,and the mRNA and protein levels of DNMT3a and DNMT3b in the hippocampus were sig-nificantly increased (P < 0.05).Compared with the group SN,group SA showed a decrease in the la-tency,more time spent in the target quadrant,and the mRNA and protein levels of DNMT3a and DNMT3b in the hippocampus were decreased (P < 0.05).There was no significant difference in the expression of DNMT1 among the four groups.Conclusion Sevoflurane exposure induces neonatal cog-nitive impairments later in life,which was accompanied by the increased mRNA and protein levels of DNMT3a and DNMT3b in the hippocampus.By contrast,pretreatment of 5-AZA decreased hipp-ocampal DNMT3a and DNMT3b,and ameliorated cognitive impairments.These results suggest that DNMTs are involved in sevoflurane induced neonatal cognitive impairments.
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The drug metabolism is a biochemical process on modification of pharmaceutical substances through specialized enzymatic systems. Changes in the expression of drug-metabolizing enzyme genes can affect drug metabolism. Recently, epigenetic regulation of drug-metabolizing enzyme genes has emerged as an important mechanism. Epigenetic regulation refers to heritable factors of genomic modifications that do not involve changes in DNA sequence. Examples of such modifications include DNA methylation, histone modifications, and non-coding RNAs. This review examines the widespread effect of epigenetic regulations on genes involved in drug metabolism, and also suggests a network perspective of epigenetic regulation. The epigenetic mechanisms have important clinical implications and may provide insights into effective drug development and improve safety of drug therapy.
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Objective To investigate the expression of DNA methyltransferases ( DNMTs) in hilar cholangiocarcinoma and its clinical significance.Methods A total of 150 samples of cholangetic tissues were collected from 111 patients with hilar cholangiocarcinoma ( cholangiocarcinoma group) and 39 patients with choledochocele ( control group) at the First Affiliated Hospital of Sun Yat-Sen University from April 1997 to March 2007.A tissue chip containing the samples of hilar cholangiocarcinoma and choledochocele was prepared.Expressions of DNMT1,DNMT3a and DNMT3b were detected by the immunohistochemical staining. Differences in the protein expressions of DNMTs in the cholangiocarcinoma group and the control group were compared,and the correlation between DNMTs protein expressions and clinicopathological features was analyzed.All data were analyzed by using the chi-square test or Fisher exact probability.The survival curve was drawn by using the Kaplan-Meier method and the survival rate was compared by using the Log-rank test.Results The rates of high protein expressions of DNMT1 and DNMT3b were 54.1％ (60/111) and 47.7％ (53/111) in the cholangiocarcinoma group, which were significantly higher than 28.2％ ( 11/39) and 23.1％ ( 9/39) in the control group ( x2 =7.740,7.240,P ＜0.05). The high protein expression of DNMT1 was correlated with-the Bismuth-Corlette classification and T staging of the tumor ( x2 =12.200, 17.800,P ＜0.05) ; there was no significant difference in the high protein expressions of DNMT3a in the cholangiocarcinoma group and the control group ( x2 =3.370.P ＞0.05 ) ; while the high protein expressions of DNMT3b was correlated with the Bismuth-Corlette classification (x2 =8.300,P ＜ 0.05 ),but not with the T staging. Sixty-six patients received hilar cholangiocarcinoma resection,and 42 of them were followed up.The median postoperative survival time of patients with low protein expression of DNMT1 was 23.9 months,which was significantly longer than 11.8 months of patients with high protein expression of DNMT1 (x2 =3.980,P ＜ 0.05).Conclusions DNMT1 and DNMT3b with high protein expression might play important roles in the carcinogenesis and development of hilar cholangiocarcinoma.There is an obvious relationship between the expression of DNMT1 and postoperative survival time of patients with hilar cholangiocarcinoma,and DNMT1 might be a valuable prognostic factor for hilar cholangiocarcinoma.
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Objective To investigate the expression of DNMT3b mRNA and microRNA-29b (miR-29b) in pancreatic cancer cells and analyze their relationship.Methods Real-time RT-PCR method was used to detect the expression of DNMT3b mRNA and miR-29b in five pancreatic cancer cell lines ( PANC1,BxPC3,CFPAC,AsPC 1,Capan 2 ) and the relationship between DNMT3b mRNA and miR-29b expression was analvzed by pearson linear correlation method.Results The expression of DNMT3b mRNA in PANC1,BxPC3,CFPAC,AsPC 1,Capan 2 were 0.497 ±0.184,0.420 ±0.168,0.439 ±0.217,0.122 ±0.111 and 0.731 ±0.387,while the expression of miR-29b were 0.745 ± 0.596,0.797 ± 1.000,0.464 ± 0.430,1.836 ± 1.623 and 0.216 ± 0.335.The expression of DNMT3b mRNA was negatively correlated with the expression of miR-29b (r =-0.922,P =0.026 ).Conclusions Both DNMT3b and miRNA29b are involved in the carcinogenesis of pancreatic cancer,and they are negatively correlated.
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Objective To investigate the expression of DNA methyltransferases (DNMTs) in liver cancer and its clinical significance. Methods The specimens of liver cancer tissues, adjacent tissues, cirrhotic tissues and chronic hepatitis tissues were collected from 50 patients who received radical resection at the First Affiliated Hospital of Sun Yat-Sen University from July 2007 to April 2008. The mRNA and protein expressions of DNMT1,DNMT3a and DNMT3b in liver cancer tissues, adjacent tissues, cirrhotic tissues and chronic hepatitis tissues were detected by real-time quantitative PCR and immunohistochemical staining. The mRNA expression of DNMTs in the liver cancer tissues was compared with those in the adjacent tissues, cirrhotic tissues and chronic hepatitis tissues by using t test and Mann-Whitney U test. The correlation between the protein expression of DNMTs in the liver cancer tissue and the clinicopathological features was analyzed by chi-square test or Fisher exact test, and the tumor-free survival time was analyzed by using Kaplan-Meier method and the difference in tumor-free survival rate between different patients was analyzed by Log-rank test. Results The mRNA expressions of DNMT1, DNMT3a and DNMT3b in the liver cancer tissue were 2.57, 2.29 and 4.86 times higher than those in the adjacent tissues (t = 3.94, 2. 72, 4. 06, P ＜ 0.05 ). The mRNA expressions of DNMT1, DNMT3a and DNMT3b were 2.38,2.14 and 4.66 times higher than those in the cirrhotic tissues, and 6.12, 4.58 and 12.99 times higher than those in the chronic hepatitis tissues. The mRNA expressions of DNMT1, DNMT3a and DNMT3b in the liver cancer tissue were significantly higher than those in the cirrhotic tissues and chronic hepatitis tissues ( U = 587.5,730. 0,562.5; 65.5, 64.5, 71.0, P ＜ 0.05). The protein expression of DNMT1 was correlated with the size, number,TNM stages and vascular invasion of tumors ( x2 = 4.08, 5.95, 4.08, P ＜ 0.05 ). The protein expression of DNMT3a was correlated with the size, number and TNM stages of tumors (x2 = 4.08, 5.95, 4.08, P ＜ 0.05 ).The mean tumor recurrence time of patients with low expressions of DNMT1 and DNMT3a were 9.4 and 8.7 months, which were significantly longer than 5.0 and 3.2 months of those with high expressions of DNMT1 and DNMT3a (x2 =3.89, 9.91, P＜0.05). Conclusions DNMTs play an important role in hepatocarcinogenesis.High expressions of DNMT1 and DNMT3a are correlated with the postoperative recurrence of liver cancer, which are valuable prognostic factors for liver cancer.
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Gastric cancer is the forth malignancy in frequency in the world. In the northern Brazil is the second neoplasia most frequent in males and the third most frequent in females. Genetic and epigenetic alterations are evolved on gastric carcinogenesis and DNA methylation is the epigenetic alteration better studied. We analyzed de novo DNA methyltransferases methylation pattern and its association with RUNX3 gene methylation pattern in Brazilian samples of intestinal-type and diffuse-type of gastric cancer. PCR methylation specific was used to evaluate DNA methylation pattern. Sixty-six samples were studied in this work. Only the gene RUNX3 presented altered methylation pattern, being methylated in 38.5% of gastric cancer intestinal-type samples and in 70% of gastric cancer diffuse-type samples and, by this reason, it should be evolved in the genesis of this neoplasia. There was a statistically significant difference among diffuse-type and intestinal-type samples (p=0.0418) and among normal and tumour tissues (p<0.0001) for RUNX3 gene but not to DNMT3A, DNMT3B e DNMT3 genes on CpG islands analyzed. Alteration of RUNX3 methylation pattern is not associated to de novo alteration of DNA methyltransferases methylation pattern on studied regionsTherefore, it becomes necessary a better comprehension of this phenomenon on gastric carcinogenesis.
El cáncer gástrico es la cuarta patología más frecuente en el mundo. En el norte del Brasil, es la segunda neoplasia más frecuente en hombres y la tercera en mujeres. Alteraciones genéticas y epigenéticas relacionadas con la carcinogénesis gástrica y la metilación del DNA son las alteraciones epigenéticas mejor estudiadas. En este trabajo, analizamos el estado de novo de metilación de genes DNA metiltransferases y su asociación con el estado de metilación del gen RUNX3 en muestras de individuos brasileños con cáncer gástrico de los tipos intestinal y difuso. Fue usada la Reacción en Cadena de la Polimerasa (PCR), metilación específica, para analizar el estado de metilación del DNA. Fueron estudiados 66 tejidos tumorales. Solamente el gen RUNX3 presentó un estado de metilación alterado, estuvo metilado en 38,5% de las muestras de cáncer gástrico tipo intestinal y en 70% de muestras de cáncer gástrico tipo difuso, lo que sugiere que estaría relacionado con la génesis de esta neoplasia. Hubo una diferencia estadística significativa entre muestras de los tipos difuso e intestinal (p=0.0418) y entre tejidos normal y tumoral (p<0.0001)parael gen RUNX3. Esta asociación no fue encontrada para los genes DNMT3A, DNMT3B y DNMT3 en las islas CpG analizadas. Alteraciones del estado de metilación de RUNX3 no están asociadas con alteraciones de novo de genes DNA metiltransferases. De esta forma se hace necesaria una mejor comprensión de este fenómeno en la carcinogénesis gástrica.
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Humans , Stomach Neoplasms/genetics , Adenocarcinoma/genetics , Core Binding Factor Alpha 3 Subunit/genetics , Methyltransferases/genetics , Polymerase Chain Reaction/methods , DNA MethylationABSTRACT
Objective To investigate the correlation between aberrant methylation status of ras association domain family 1A (RASSF1A) , transcriptional levels of DNA methyltransferases (DNMTs) and hepatitis B virus ( HBV) infection in patients with hepatocellular carcinoma ( HCC). Methods HCC samples in 61 cases were collected. Aberrant methylation status of RASSF1A was detected using methylation specific PCR (MSP). Transcriptional levels of DNMT1, DNMT3 A and DNMT3B was measured using semi-quantitative reverse transcriptase-PCR(RT-PCR). Results RASSF1A gene with abnormal methylation in initiation zone was found in 45 cases with HCC among 61 patients (73.8%). Further analysis revealed RASSF1A methylated in 32 of 47 HBV infected cases and in 13 of 14 uninfected cases. However, there was no significant association between methylation status of RASSF1A and HBV infection (x2 =2.260, P = 0. 133). Compared with normal control, DNMTs was up-regulated in all HCC samples, HCC cell lines and HBV infected group. Analysis within each group indicated that DNMT3A and DNMT3B levels of HCC increased in MSP positive cases ( t = 3. 494, P
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Objective To investigate the relationship between the expression of DNA methyltransferases(DNMT)and clinical prognosis in children with acute leukemia(AL).Methods The mRNA expressions of DNMT1,DNMT3A,DNMT3B,p15,mdrl were measured in 56 AL children and 20 normal controls by semi-quantitative reverse transcriptionpolymerse chain reaction.Results In 56 cases of children with AL,the positive rate of DNMT1 was 73.2%(41/56);the positive rate of DNMT3A was 67.9%(38 /56);the positive rate of DNMT3B was 64.3%(36/56).Thirty-one cases showed positive expressions of the 3 DNMT simultaneously,4 cases with negative expressionss imultaneously,21 cases with at least 1 positive expression of the DNMT,positive rate of p15 was 19.6%(11/56);positive rate of mdrl was 28.6%(16/56),all 3 simultaneous expressions of the 3 DNMT in AL children were significantly higher than those in normal controls(P