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OBJECTIVE@#To explore whether casticin (CAS) suppresses stemness in cancer stem-like cells (CSLCs) obtained from human cervical cancer (CCSLCs) and the underlying mechanism.@*METHODS@#Spheres from HeLa and CaSki cells were used as CCSLCs. DNA methyltransferase 1 (DNMT1) activity and mRNA levels, self-renewal capability (Nanog and Sox2), and cancer stem cell markers (CD133 and CD44), were detected by a colorimetric DNMT activity/inhibition assay kit, quantitative real-time reverse transcription-polymerase chain reaction, sphere and colony formation assays, and immunoblot, respectively. Knockdown and overexpression of DNMT1 by transfection with shRNA and cDNA, respectively, were performed to explore the mechanism for action of CAS (0, 10, 30, and 100 nmol/L).@*RESULTS@#DNMT1 activity was increased in CCSLCs compared with HeLa and CaSki cells (P<0.05). In addition, HeLa-derived CCSLCs transfected with DNMT1 shRNA showed reduced sphere and colony formation abilities, and lower CD133, CD44, Nanog and Sox2 protein expressions (P<0.05). Conversely, overexpression of DNMT1 in HeLa cells exhibited the oppositive effects. Furthermore, CAS significantly reduced DNMT1 activity and transcription levels as well as stemness in HeLa-derived CCSLCs (P<0.05). Interestingly, DNMT1 knockdown enhanced the inhibitory effect of CAS on stemness. As expected, DNMT1 overexpression reversed the inhibitory effect of CAS on stemness in HeLa cells.@*CONCLUSION@#CAS effectively inhibits stemness in CCSLCs through suppression of DNMT1 activation, suggesting that CAS acts as a promising preventive and therapeutic candidate in cervical cancer.
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Female , Humans , Cell Line, Tumor , HeLa Cells , Neoplastic Stem Cells/metabolism , RNA, Small Interfering/metabolism , Uterine Cervical Neoplasms/metabolismABSTRACT
Objective:To investigate the effects of cell adhesion molecule 1 (CADM1) promoter methylation in ovarian cancer on gene transcription and protein expression levels, and the regulation mechanism of mirNA-148A on CADM1 methylation levels.Methods:A total of 86 patients with ovarian cancer who received surgical treatment in the Affiliated Hospital of Hangzhou Normal University from Jun. 2018 to Jun. 2020 were selected as study subjects. The methylation level of CADM1 gene CpG island in ovarian cancer tissues and adjacent tissues was quantitatively detected. Quantitative real-time polymerase chain reaction was used to detect the mRNA and mirNA-148a expressions of CADM1 gene. The CADM1 gene and DNMT1 protein levels were detected by Western blot. Human ovarian cancer SKOV3 cells were treated with different concentrations of methyltransferase inhibitors (5-Azacytidine, 5-aza) , and CADM1 mRNA expression was detected 72 h later. Human ovarian cancer cell lines SKOV3 were transfected with mir-335-5p mimic, inhibitor and negative control respectively. Then mir-335-5p expression level and CADM1 gene methylation level were detected after transfection.Results:The methylation level of CADM1-1 island in ovarian cancer tissues was 2.89%±0.82%, significantly higher than that of paracancerous normal tissues 1.86%±0.68% ( t=4.936, P<0.001) , and that of CADM1-2 island in ovarian cancer tissues was 3.12%±0.93%, significantly higher than that of paracancerous normal tissues (2.27%±0.69%, t=5.114, P<0.001) . Pearson correlation analysis showed that the methylation level of CADM1-1 island and CADM1-2 island in ovarian cancer tissues was significantly negatively correlated with the relative mRNA expression (r was -0.615 and -0.582, respectively, and both P<0.001) , and with the protein expression level of CADM1 (r was -0.521 and -0.612, respectively, and both P<0.001) . The relative expression level of mirNA-148a in ovarian cancer tissues was 1.53±0.42, significantly lower than that in paracancer tissues (2.59±0.73, t=6.113, P<0.001) . After treatment with different concentrations of 5-AZA, mRNA expression levels of CADM1 gene in SKOV3 cells were significantly higher in the low concentration group and the high concentration group than in the control group (both P<0.05) , and mRNA expression levels in the high concentration group were significantly higher than in the low concentration group ( P<0.05) . After mirNA-148A transfected SKOV3 cells, the relative expression levels of mirNA-148a in the mimic group were significantly increased, while those of inhibitor group were significantly decreased ( P<0.001) . The DNMT1 expression level and CADM1 gene methylation level of mimic group were significantly decreased, while those of inhibitor group were significantly increased (P<0.001) . Conclusion:In ovarian cancer, miRNA-148a can regulate the DNA methylation level of CADM1 gene by acting on the downstream target protein DNMT1, thus affecting the mRNA and protein expression levels of CDM1 gene and participating in the pathogenesis of ovarian cancer.
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Objective:To analyze the relationship between DNA methyltransferase 1 (DNMT1) and forkhead box O3a (FOXO3a) in colon cancer and the diagnostic efficacy of combined detection in predicting the occurrence of colon cancer by detecting the levels of DNMT1 and FOXO3a in serum of colon cancer patients.Methods:A total of 105 patients with colon cancer diagnosed and treated in Xi′an International Medical Center Hospital from September 2019 to September 2020 were selected as the colon cancer group, and 65 patients with colon polyps diagnosed by biopsy during the same period were selected as control group. The levels of DNMT1 and FOXO3a in serum of patients were detected by real-time fluorescence quantitative PCR. Pearson correlation coefficient method was used to analyze the correlation between the levels of DNMT1 and FOXO3a in serum of patients with colon cancer. Subject operating characteristic curve was used to evaluate the diagnostic values of DNMT1 and FOXO3a levels in colon cancer.Results:The serum levels of DNMT1 in the control group and colon cancer group were 0.93±0.28 and 1.34±0.35, compared with the control group, the level of DNMT1 in the colon cancer group was significantly higher, with a statistically significant difference ( t=7.990, P<0.001). The serum levels of FOXO3a were 1.04±0.39 and 0.69±0.18, compared with the control group, the level of FOXO3a in the colon cancer group was significantly lower, with a statistically significant difference ( t=7.940, P=0.001). The serum levels of DNMT1 and FOXO3a in patients with colon cancer were negatively correlated ( r=-0.687, P<0.001). The area under the curve (AUC) of DNMT1 predicting colon cancer was 0.843, the sensitivity was 71.40%, and the specificity was 90.80%. The AUC of FOXO3a predicting colon cancer was 0.812, the sensitivity was 88.60%, and the specificity was 67.70%. The AUC of the two combined predicting colon cancer was 0.859, the sensitivity was 89.50%, and the specificity was 92.30%. Compared with FOXO3a single detection, the predictive value of combined detection of DNMT1 and FOXO3a were higher ( Z=1.982, P=0.047). Conclusion:The level of DNMT1 in the serum of patients with colon cancer is increased, while the level of FOXO3a is decreased. There is a negative correlation between them in the serum of patients with colon cancer. The combined detection of the DNMT1 and FOXO3a can effectively improve the diagnostic value of colon cancer.
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Objective:To explore the role ofDNA methyltransferase 1 (DNMT1) in mouse skin aging.Methods:Epidermal conditional K14 Cre-mediated DNA methyltransferase 1 (DNMT1) knockout mice (Mut group,n=4) and the littermate normal mice with the same age (WT group) n=4) were used in this study.HE staining was used to detect the pathological changes of skin;the changes of number in the dermal elastic fibers were detected by Gomori aldehyde fuchsin staining,the number of 5-bromo-2-deoxyuridine (BrdU)-labeled transit amplifying cells (TAC) in epidermis were detected by immunohistochemical staining;the number of chlorodeoxyuridine (CldU)-labelretaining cells (LRC) in epidermis were detected by immunofluorescent staining.Results:Compared with the WT group,the skin showed premature aging symptoms in the Mut group concomitant with the decreased epidermal thickness as well as the number of dermal collagen fibers,while the increased dermal elastic fiber fracture.Compared with the WT group,the number of TAC in the epidermis was significantly increased (P＜0.05),and the number of LRC was significantly decreased (P＜0.05) in the Mut group.Conclusion:The phenotype of skin premature aging in epidermal stem cell conditional DNMT1-knockout mice suggests an important role of DNMT 1 in skin aging.
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Objective To investigate the expression and clinical significance of DNMT1 and CCNA1 in different grades of cervical lesions. Methods Cervical tissues were selected from normal cervical(NC),low-grade cervical intraepithelial lesion(LSIL),high-grade cervical intraepithelial lesion(HSIL)and cervical squa-mous cell carcinoma(SCC)from each thirty patients.The expression of DNMT1 and CCNA1 mRNA and protein was examined by Western Blot analysis and qRT-PCR in cervical tissues. Results The expression of DNMT1 mRNA and protein in LSIL,HSIL and SCC was higher than in NC(F=117.93,P<0.05;F=61.24,P<0.05). Expression of DNMT1 mRNA and protein was increased steadily according to severity of cervical lesions(χ2trend=26.25,P<0.05;χ2trend=26.60,P<0.05).The expression of CCNA1 mRNA and protein in HSIL and SCC was lower than that in NC and LSIL(F = 77.04,P < 0.05;F = 57.15,P < 0.05). Expression of CCNA1 mRNA and protein was decreased steadily according to severity of cervical lesions(χ2trend=64.19,P<0.05;χ2trend=60.24,P<0.05). There was a negative correlation between expression of DNMT1 and CCNA1 protein in LSIL,HSIL,SCC (r=-0.75,-0.56,P<0.05). Conclusion In DNMT1 mRNA there is high expression of protein and in CCNA1 mRNA there is low expression of protein,but both may be related to the occurrence and development of cervical cancer.
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AIM: To explore the effect of pyrrolidine dithiocarbamate (PDTC), an NF-κB inhibitor, on the proliferation and apoptosis of human multiple myeloma U266 cells and its mechanisms.METHODS: The U266 cells were treated with PDTC at different concentrations (0, 25, 50, 100 and 200 μmol/L) in vitro.The growth inhibitory rate of the U266 cells was detected by CCK-8 assay and cell counting.The cell cycle of the U266 cells was determined by flow cyto-metry, and the apoptosis was examined by flow cytometry with Annexin V-FITC/PI staining.The effect of PDTC on the expression of DNA methyltransferase 1 (DNMT1) at mRNA and protein levels was measured by RT-qPCR and Western blot, respectively.The effects of PDTC on the protein levels of NF-κB (P65), DNMT1, Bcl-2, cyclin D1, cleaved caspase-3 and cleaved caspase-8 were determined by Western blot.RESULTS: The protein level of NF-κB (P65) was decreased after treatment with PDTC for 48 h or 72 h.PDTC inhibited the proliferation of U266 cells in both dose-and time-dependent manners.After treatment with PDTC for 48 h, the percentage of U266 cells in G2 phase increased compared with control group (P<0.05).PDTC induced the apoptosis of U266 cells in a dose-dependent manner.The expression of DNMT1 at mRNA and protein levels decreased (P<0.05).The results of Western blot showed that the expression of Bcl-2 in PDTC groups decreased, while the protein levels of cyclin D1, cleaved caspase-3 and cleaved caspase-8 were higher than those in control group (P<0.05).CONCLUSION: The NF-κB inhibitor PDTC inhibits the proliferation of U266 cells by inducing cell apoptosis.It may be related to the down-regulated expression of DNMT1, cell cycle arrest and activation of the apoptotic pathways.
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BACKGROUND: Mesenchymal stem cells (MSCs) play an important role in hematopoietic stem cell (HSC) maintenance, proliferation, and apoptosis. DNA methyltransferase 1 (DNMT1) is considered an essential factor in the maintenance of HSCs in mammalian cells. Therefore, this study was conducted to evaluate the mRNA expression level of DNMT1 during cord blood (CB)-HSC ex vivo expansion with MSCs. METHODS: Ex vivo cultures of CB-HSCs were performed in three culture conditions for 7 days: cytokines, cytokines with MSCs, and only MSCs. Total and viable cell numbers were counted after 5 and 7 days using trypan blue stain, and the stem cell percentage was then evaluated by flow cytometry. Moreover, in vitro colony-forming unit assay was carried out to detect clonogenic potential of HSCs at days 0 and 7 using MethoCult H4434. Finally, DNMT1 mRNA expression level was evaluated by real-time polymerase chain reaction. RESULTS: Maximum CB-CD34⁺ cell expansion was observed on day 7 in all the three cultures. After 7 days, ex vivo expansion of CB-CD34⁺ cells indicated a significant decrease in DNMT1 expression in the cytokine cultures, whereas in the two co-culture conditions DNMT1 expression was increased. A significant difference between the number of CD34⁺ and CD34⁻ cells in the cytokine co-culture system was observed. CONCLUSION: These data indicated that an elevated expression of DNMT1 is associated with increased expansion and proliferation of HSCs co-cultured with human MSCs. Hence, DNMT1 may be a potential factor in the maintenance of expanded HSCs co-cultured with human MSCs.
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Humans , Apoptosis , Cell Count , Coculture Techniques , Cytokines , DNA , Fetal Blood , Flow Cytometry , Hematopoietic Stem Cells , In Vitro Techniques , Mesenchymal Stem Cells , Real-Time Polymerase Chain Reaction , RNA, Messenger , Stem Cells , Trypan BlueABSTRACT
Objective To explore the characteristics and biological functions of epigenetic treatment to DNMT1 expression in NSCLC cell lines. Methods Lung cancer cells were divided into 4 groups , and drugs with different concentrations. The effect of epigenetic treatment on NSCLC cell line was detected by CCK-8 and MTT. The effect of epigenetic treatment on the expression of DNMT1 in NSCLC cell line was detected by Western blot. Results CCK-8 and MTT assay showed that treatment with 5-Aza-CdR and MS-275 inhibited the proliferation of NSCLC cells. Western blot showed that treatment with 5-Aza-CdR and MS-275 inhibited the DNMT1 expression in NSCLC cells. Conclusion The expression of DNMT1 gene in the NSCLC cell lines may be suppressed effectively by epigenetic treatment , and the gene may inhibit the proliferation and growth of NSCLC cell lines.
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The expression of DNA methyltranferase 1 (DNMT1 )mRNA and protein in 20 controls of normal oral mucosa tissue and 43 cases of oral squamous cell carcinoma(OSCC)was detected by Real-Time PCR and immunohistochemical staining and Western blot respectively. DNMTl mRNA CT values in OSCC and the controls were 0.958 6 ±0.986 6 and 0.459 5 ±0.525 8 respectively(Z =-2.028,P <0.05), The positive expression of DNMT1 protein in OSCC and the controls was 87% and 25% respectively(P <0.05).DNMT1 may play a role in the development of OSCC.
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Objective To probe into the expression features of EZH2 and DNMT1 in triple-negative breast cancer (TNBC), and the relations between the expression and the main clinical pathological parameters of TNBC. Methods The clinical and pathological data of 209 cases of breast cancer (including 131 cases of TNBC and 78 cases of non-TNBC) in Guangzhou Kingmed Center for Clinical Laboratory from Jan. 2008 to May 2013 were retrospectively analyzed. Immunohistochemistry SP assay was performed to determine the expressions of EZH2 and DNMT1 in 209 paraffin-embedded specimens of breast cancer and 65 specimens of normal tissue (more than 4cm away from tumor). The differences of protein expression in the specimens were compared, and correlation analysis was performed to disclose the relationship between protein expression and clinico-pathological indices. Multivariate logistic regression analysis was applied to analyze the positive expression-related factor of EZH2 and DNMT1. Spearman rank correlation analysis was used to analyse the interrelation of EZH2 and DNMT1 in TNBC. Results The positive expression rates of EZH2 in TNBC, non-TNBC and adjacent breast tissue were 86.3%, 89.7% and 40.0%, respectively, while the positive expression rates of DNMT1 were 63.4%, 66.6% and 44.6%, respectively. The positive expression rates of EZH2 and DNMT1 were higher in both TNBC and non-TNBC tissues than in adjacent breast tissue (P0.05), but the positive expression of EZH2 in TNBC was related to the pathological grade, tumor size and lymph node metastasis (P<0.05), and the positive expression of DNMT1 was related to the pathological grade and lymph node metastasis (P<0.05). Multivariate logistic regression analysis demonstrated that the pathological grade of tumor was the main factor affecting the expressions of EZH2 and DNMT1, and the expressions of EZH2 and DNMT1 in TNBC were positively correlated (r=0.34, P<0.01). Conclusion The high expressions of EZH2 and DNMT1 are correlated with the differentiation, growth and metastasis of TNBC. Combined detection of the expressions of EZH2 and DNMT1 may be more valuable in determination of prognosis of patients with TNBC.
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Objective To study the relationship between DNA methylation and pathogenesis of childhood immune thrombocytopenic purpura (ITP) by examining the expression of DNA methyltransferase 1(Dnmt1) and DNA methyltransferase 3a (Dnmt3a) mRNA in peripheral blood lymphocytes of the children with ITP. Methods Expression of Dnmt 1 and Dnmt3a mRNA in the peripheral blood lymphocytes in 36 children with newly diagnosed ITP and 26 healthy children were detected using RT-PCR. Results Dnmt1 mRNA expression in peripheral blood lymphocytes in children diagnosed with ITP was 3.02±0.49, significantly lower than 4.58±0.52 in the control group (t=11.95, P<0.001). Dnmt3a mRNA expression in peripheral blood lymphocytes in children diagnosed with ITP was 1.49±0.44, signiifcantly lower than 2.41±0.32 in the control group (t=9.12, P<0.001). Conclusions Children with newly diagnosed ITP have lower DNA methylation status in peripheral blood lymphocytes as compared to that in healthy children. The DNA methylation may play an important role in the etiology of acute ITP in children.
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Objective To investigate the expression of DNM T1 and PDCD4 in Tongue Squamous cell carcinoma and their signif‐icance to Clinical .Methods The protein expression of DNM T1 and PDCD4 in 40 cases of TSCC tissues and The adjacent no tumor tissues were measured by Elivision Two Step immunohistochemical method(IHC) ,the relationship between DNM T1 ,PDCD4 and clinicopathological parameters were analyzed .Results There was positively over expression of DNM T1 while the expression of PD‐CD4 was at a low lever or lost in TSCC tissues ,the expression of two genes DNM T1 and PDCD4 in the adjacent no tumor tissues were in contrast ;there was a significant negative correlation between DNM T1 and PDCD4 expression in TSCC(r = - 0 .452 ,P<0 .05) .The expression of DNM T1 protein were associated with histopathological differentiation types ,regional lymph node metasta‐sis and TNM staging(P< 0 .05) ,it had nothing to do with age and gender ;the expression of PDCD4 protein were associated with regional lymph node metastasis and TNM staging(P< 0 .05) ,and it had nothing to do with age ,gender ,histopathological differenti‐ation types .Conclusion Implying the abnormal expression of DNM T1 and PDCD4 protein might be closely related to the develop‐ment and progression of TSCC .DNM T1 may be participates in the inactivation of PDCD4 expression ,and led to the development of the cancer at last .
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Objective To explore the effects of folate on the expression of DNA methyltransferase 1 (DNMT1) and methyl-CpG-bingding protein 2 (MeCP2) in cervical cancer cell lines.Methods Experimental study was carried out in vitro.Human cervical cancer cell lines,including C33A cell with HPV negative and Caski cell with HPV16 positive,were treated with different concentration of folate.The expression of DNMT1 and MeCP2 protein (by Western blot)and mRNA (by real-time PCR) were then detected in the two cell lines.Results It was found that supplement of folate was able to reduce the cell proliferation in C33A cell (r=0.984,P＜0.001) and Caski cell (r=0.978,P=0.002),as well as induced the cell apoptosis (C33A:r=0.989,P＜0.001 ;Caski:r=0.994,P＜0.001).Results showed that the expression levels of DNMT1 protein (C33A:r=-0.914,P＜ 0.001 ; Caski:r=-0.859,P=0.003) and MeCP2 protein (C33A:r=-0.830,P=0.005 ;Caski:r=-0.981,P＜0.001) decreased gradually with the increase of folate concentrations,but the expression of DNMT1 and MeCP2 mRNA was not observed in Caski or C33A cell.When at the same levels of folate,the expression of DNMT1 protein or mRNA was higher in Caski cell than in C33A cell.However,the expression of MeCP2 protein or mRNA was higher in C33A cell than in Caski cell.Conclusion Our fimding indicated that adequate foleta could effectively inhibit the proliferation of cervical cancer cells and facilitate their apoptosis in vitro,thus would reverse the aberration protein expression of DNMTl and MeCP2.That there might be a synergistic action between HPV16 infection and parafunction of DNMT l in cervical cancer,being noticed.
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Objective To explore the effects of aberrant expression of DNA methyltransferase 1 (DNMT1) in cervical cancerization tissue and cervical cancer cells.Methods Cervical tissues were collected from 80 cases with a diagnosis of invasive cervix squamous cell carcinoma (SCC),53 cases with high-grade cervical intraepithelial neoplasia (CIN Ⅱ/Ⅲ),52 cases with low-grade cervical intraepithelial neoplasia (CIN Ⅰ)and 53 cases with normal cervix (NC).Meanwhile,Caski (HPV16-positive) and C33A (HPV-negative) cells selected from cervical cancer cell lines were cultured routinely in vitro.The expression of DNMT1 protein and mRNA were examined by Western blot analysis and real-time PCR (qRT-PCR) in the tissues and cells,respectively.Results The levels of DNMT1 protein were 1.33,1.84 and 2.28,and the Ct-ratios (DNMT1/β-actin) of DNMT1 mRNA were 1.27,1.27 and 1.26 in CIN Ⅰ,CIN Ⅱ/Ⅲand SCC group,respectively.Comparing with NC group,the expression of DNMT1 protein or mRNA was elevated in deficient cervical groups,with statistical significance (F =110.57,P ＜ 0.001,F =2.68,P =0.048).The expression levels of DNMT1 protein were increased steadily according to severity of the cervix lesions (x2tend =50.80,P ＜ 0.001),however,the expression of DNMT1 mRNA was not observed the same tendency (x2tend =3.63,P ＞ 0.05).The results from experiment in vitro showed that the levels of DNMT1 protein or mRNA were both higher in Caski cell than in C33A cell,especially for DNMT1 mRNA with significantly difference (t =7.134,P =0.002).Conclusion Aberrant expression of DNMT1 protein or mRNA could link with the risk of cervical cancerization by both transcriptional and posttranscriptional mechanisms.There would be a synergistic effect between overexpression of DNMT1 and HPV16 infection in the progression of cervix carcinogenesis.
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Objective To explore the effect of folic acid and DNA methyltransferase 1 (DNMT1) on cervical cancer and cervix precancerous lesion. Methods 100 patients with cervix squamouscell carcinoma (SCC), 101 patients with cervical intraepithelial neoplasm (CIN) and 109 patients with cervix inflammation (CI) diagnosed by histology were included in this study. Radioimmunoassay (RIA), polymerase chain reaction (PCR) and Western blot were used to detect the levels of serum folate, HPV16 infection and the expression of DNMT1 protein,respectively. Results The average levels of serum folate were (2.60 ± 1.61) ng/ml, (3.14 + 2.08) ng/ml and (3.32+1.74) ng/ml,and the expression of DNMT1 protein were 2.40 + 0.99,1.88 + 0.33 and 0.89 ± 0.29 in the group of SCC, CIN and CI, respectively.The relationship of folate levels and DNMT1 protein expression showed inverse correlation (r=-0.186, P=0.00l). The results in our study indicated that there was an additive interaction between low-level of serum folate and high-expressionof DNMT1 protein related to the risk of CIN and SCC, with OR value as 2.50(95%C/: 1.21-9.22) and 6.03 (95%C/: 2.79-21.72) respectively. The relative excessrisk of interaction (RERI) , attributableproportion of interaction (API) and synergy index (S) were 0.92, 0.36 and 2.59 in the CIN group while 2.47, 0.41 and 1.96 in the SCC group. Conclusion The low level of serum folate and high expression of DNMT1 protein seemed to be associated with high risk of cervical cancer and its precancerous lesion. It suggested that there might be a synergistic action between serum folate and DNMT1 in the progression of cervix carcinogenesis.
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Objective To investigate the transcription and expression of DNA methyltransferase 1 (DNMT1) mRNA in endemic arsenism patients by burning coal usage,to probe its effects on the development and carcinogenesis of arsenism. Methods In 2008,68 arsenism patients(including 24 mild cases,28 moderate cases and 16 severe cases) were selected in the areas with endemic arsenism according to Standarding of Diagnosis for Endemic Arsenism from Xingren county,Guizhou province. Among the subjects,40 cases were diagnosed by pathological methods,and they were divided into general pathological changes(20),precancerous(14) and cancerous group(6). Tweleve kilometer away from the endemic arsenism area,23 controls were selected in Daguoduo village (non-arsenism exposure). Under the principle of informed consent,blood samples were collected from individuals. The mRNA expression of DNMTI was detected by real-time quantitative reverse transcription polymerase chain reaction(FQ-PCR). At the same time,skin tissue samples were collected from the voluntary surgical treatment patients with endemic arsenism (total 61 cases,including 34 general pathological changes cases,21 precancerous cases and 6 cancerous cases) and from the control(15 cases). DNMT1 protein was detected by immunohistochemical method.Results Average level of DNMT1 mRNA were 0.221 83±0.595 09,0.246 11±0.509 79 and 0.389 27±0.411 33 respectively among mild,moderate and severe arsenism group. DNMT1 mRNA level of mild and moderate group were obviously lower than the control group(0.695 95±0.463 98,all P < 0.01). The mRNA average level of DNMT1 were 0.320 64±0.547 46,0.313 09±0.529 13 and 0.159 07±0.342 56 individually among general pathological changes,precancerous and cancerous group,which were obviously lower than the control group(0.695 95±0.463 98,all P < 0.05). The expression rates of DNMT1 protein in skin were 88.24%(30/34),100%(21/21) and 100% (6/6) among general pathological changes,precancerous and cancerous group were higher than the control group [0(0/15),all P < 0.01],and the extent of expression gradually increased with the aggravation of skin damage(r,= 0.740,P < 0.01). Conclusions DNMT1 participated in the development of the arsenism. High expression of its protein was an early event during the process of the arsenism. DNMT1 may be the new target markers for early diagnosis and treatment of arsenism.
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Hypermethylation in the promoter region is an important epigenetic mechanism for the transcriptional repression of a number of cancer-associated genes, and over-expression and/or increased activity of DNA methyltransferases are considered to be the main cause of promoter hypermethylation. In order to explore the roles of two methyltransferase members (DNMT1 and DNMT3b) in the cholangiocarcinoma tumorigenesis, antisense eukaryotic expression plasmid of DNMT1 and DNMT3b gene was constructed respectively, and were co-transfected into the human cholangiocarcinoma cell line QBC-939 to observe their biological effects on the cell growth and proliferation ability, apoptosis, cell cycle alteration, and the tumorigenesis ability in the subcutaneous tissue of nude mouse. The results demonstrated that co-transfection with antisense eukaryotic expression plasmid of DNMT1 and DNMT3b gene and single transfection with antisense eukaryotic expression plasmid of DNMT1 gene can suppress the growth and proliferation of QBC-939, block the cell cycle at G1 phase, increase the apoptosis rate, minimize the tumor size in the subcutaneous tissue of nude mouse. The suppressing biological effect of co-transfection is stronger than single transfection with antisense DNMT1. Meanwhile, single transfection with antisense eukaryotic expression plasmid of DNMT3b gene has no effects on the biological characteristics of QBC-939. This study suggests that DNMT1 gene plays a key role in DNA methylation and DNMT3b gene may act as an accessory to support its function in inactivation of tumor suppressor genes. Combination DNMT1 and DNMT3b will inhere their biological effects and have the synergistic effect on suppressing the growth of human cholangiocarcinoma cell line QBC-939.
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OBJECTIVE: Epigenetics is an important, alternative mechanism of gene regulation that is independent of the nucleotide sequences of DNA. We investigated mRNA levels for DNA methyltransferase-1 (DNMT-1), and the effect of estrogen on the expression of DNMT-1 level in T cells and B cells from patients with systemic lupus erythematosus (SLE) and healthy subjects, and assessed the possible etiological role of DNA methylation in the pathogenesis of SLE. METHODS: mRNA levels for DNMT-1 in CD4+ T cells and CD19+ B cells from 37 patients with SLE and 12 healthy controls were examined using RT-PCR. We used specific primer for DNMT-1 and beta actin, The effect of estrogen on the DNA methylation was measured by the mRNA level of DNMT-1 CD4+ T cells and CD19+ B cells treated with 100 nM of 17beta-estradiol for 72 hour. RESULTS: The levels of DNMT-1 mRNA were significantly lower in CD4+ T cells and CD19+ B cells from SLE patients compared with healthy controls. We observed the suppression of the levels of DNMT-1 mRNA by stimulated with estrogen in patients with SLE patients, especially in CD19+B cells. DNA hypomethylation of B cells was tend to be correlated with the level of anti-ds DNA antibody without statistical significance (r=-0.43, p=0.3). CONCLUSION: Our observations suggest that suppression of DNMT-1 by estrogen in B cells from patients with SLE might be related to the pathogenesis of SLE. Epigenetic studies may provide clues for developing new treatment strategies of SLE.
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Humans , Actins , B-Lymphocytes , Base Sequence , DNA Methylation , DNA , Epigenomics , Estrogens , Lupus Erythematosus, Systemic , RNA, Messenger , T-LymphocytesABSTRACT
Background and purpose:More and s’more evidence has demonstrated that DNMT1 was expressed at high levels in many different kinds of human tumor tissues or cells,suggesting that high expression of DNMT1 was closely associated with occurrence and development of tumors.In this study,effect of down-regulation of DNMT1 on cell proliferation and migration ability of esophageal squamous cell carcinoma(ESCC) cell line EC9706 cells was studied and its related mechanism was explored.Methods:Cell proliferation assay was investigated using CCK-8 Kit,cell migration ability was analyzed using Boyden chamber and the expressions of DNMT1 and MMP-2 were detected by Real-time PCR and Western blotting methods.Results:The result of cell proliferation experiment showed that down-regulation of DNMT1 could markedly inhibit cell proliferation in EC9706 cells.After transfection with DNMT1 siRNA,invasiveness and metastasis ability of EC9706 cells displayed an obvious decrease(P
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Objective To study the expression of DNA methyltransferase 1 (DNMT1) in human cervical carcinoma tissue and cells, analyze the relationship between the expression level of DNMT1 and the clinicopathologic features of cervical carcinoma, and explore the role DNMT1 plays in tumorigenesis of cervical carcinoma. Methods The expression levels of DNMT1 protein in 3 cervical cancer cell lines, 89 samples of cervial cancer tissue, 20 samples of cervical intraepithelial neoplasia (CIN) and 20 samples of normal cervix were determined by immunohistochemistry method. The expression levels of DNMT1 mRNA in all the cell lines and 79 paraffin sections of cervix tissue were determined by RT-PCR. Results The DNMT1 protein was expressed in all the three cervix cancer cell lines. Positive expression was detected in 71.9% of cervix cancer samples, 35.0% of CIN samples and 10.0% of normal cervix samples, with significant differences among the three groups (P