scholarly journals Role of NADPH oxidase NOX5-S, NF-κB, and DNMT1 in acid-induced p16 hypermethylation in Barrett's cells

2013 ◽  
Vol 305 (10) ◽  
pp. C1069-C1079 ◽  
Author(s):  
Jie Hong ◽  
Dan Li ◽  
Jack Wands ◽  
Rhonda Souza ◽  
Weibiao Cao
Keyword(s):  
Cell Proliferation ◽  
T Cells ◽  
Nadph Oxidase ◽  
Mrna Expression ◽  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Promoter Hypermethylation ◽  
P16 Gene

Inactivation of tumor suppressor genes via promoter hypermethylation may play an important role in the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA). We have previously shown that acid-induced p16 gene promoter hypermethylation may depend on activation of NADPH oxidase NOX5-S in BAR-T cells and OE33 EA cells. DNA methyltransferase 1 (DNMT1) is known to participate in maintaining established patterns of DNA methylation in dividing cells and may play an important role in the development of cancer. Therefore, we examined whether DNMT1 is involved in acid-induced p16 gene promoter hypermethylation in BAR-T cells. We found that the acid significantly increased p16 gene promoter methylation, decreased p16 mRNA, and increased cell proliferation, effects that may depend on activation of DNMT1 in BAR-T cells. DNMT1 is overexpressed in EA cells FLO and OE33 and EA tissues. Acid treatment upregulated DNMT1 mRNA expression and increased DNMT1 promoter activity. Acid-induced increases in DNMT1 mRNA expression and promoter activity were significantly decreased by knockdown of NOX5-S and NF-κB1 p50. Conversely, overexpression of NOX5-S, p50, or p65 significantly increased DNMT1 promoter activity. Knockdown of NOX5-S significantly decreased the acid-induced increase in luciferase activity in cells transfected with pNFκB-Luc. An NF-κB binding element GGGGTATCCC was identified in the DNMT1 gene promoter. We conclude that the acid-induced increase in p16 gene promoter methylation, downregulation of p16 mRNA, and increase in cell proliferation may depend on activation of DNMT1 in BAR-T cells. Acid-induced DNMT1 expression may depend on sequential activation of NOX5-S and NF-κB1 p50.

scholarly journals Acid-induced p16 hypermethylation contributes to development of esophageal adenocarcinoma via activation of NADPH oxidase NOX5-S

2010 ◽  
Vol 299 (3) ◽  
pp. G697-G706 ◽  
Author(s):  
Jie Hong ◽  
Murray Resnick ◽  
Jose Behar ◽  
Li Juan Wang ◽  
Jack Wands ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Nadph Oxidase ◽  
Cell Line ◽  
Esophageal Adenocarcinoma ◽  
Promoter Methylation ◽  
Mrna Level ◽  
Gene Promoter ◽  
Acid Reflux ◽  
Suppressor Gene ◽  
P16 Gene

Inactivation of tumor suppressor gene p16 may play an important role in the progression from Barrett's esophagus (BE) to esophageal adenocarcinoma (EA). Hypermethylation of p16 gene promoter is an important mechanism inactivating p16. However, the mechanisms of p16 hypermethylation in EA are not known. Therefore, we examined whether acid increases methylation of p16 gene promoter and whether NADPH oxidase NOX5-S mediates acid-induced p16 hypermethylation in a Barrett's cell line BAR-T and an EA cell line OE33. We found that NOX5-S was present in BAR-T and OE33 cells. Acid-induced increase in H2O2 production and cell proliferation was significantly reduced by knockdown of NOX5-S. Exogenous H2O2 remarkably increased p16 promoter methylation and cell proliferation. In addition, acid treatment significantly increased p16 promoter methylation and decreased p16 mRNA level. Knockdown of NOX5-S significantly increased p16 mRNA, inhibited acid-induced downregulation of p16 mRNA, and blocked acid-induced increase in p16 methylation and cell proliferation. Conversely, overexpression of NOX5-S significantly decreased p16 mRNA and increased p16 methylation and cell proliferation. In conclusion, NOX5-S is present in BAR-T cells and OE33 cells and mediates acid-induced H2O2 production and cell proliferation. NOX5-S is also involved in acid-induced hypermethylation of p16 gene promoter and downregulation of p16 mRNA. It is possible that acid reflux present in BE patients may activate NOX5-S and increase production of reactive oxygen species, which in turn increase p16 promoter methylation, downregulate p16 expression, and increase cell proliferation, thereby contributing to the progression from BE to EA.

scholarly journals Promoter Methylation ofSFRP3Is Frequent in Hepatocellular Carcinoma

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Ya-Wen Lin ◽  
Yu-Lueng Shih ◽  
Gi-Shih Lien ◽  
Fat-Moon Suk ◽  
Chung-Bao Hsieh ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Chronic Hepatitis ◽  
Mrna Expression ◽  
Cell Lines ◽  
Promoter Methylation ◽  
Promoter Hypermethylation ◽  
Polymerase Chain ◽  
Related Proteins ◽  
And Control

Oncogenic activation of the Wnt/β-catenin signaling pathway is common in human cancers. The secreted frizzled-related proteins (SFRPs) function as negative regulators of Wnt signaling and have important implications in carcinogenesis. Because there have been no reports about the role ofSFRP3in hepatocellular carcinoma (HCC), we investigated the level of methylation and transcription ofSFRP3. Four HCC cell lines, 60 HCCs, 23 cirrhosis livers, 37 chronic hepatitis livers, and 30 control livers were prescreened forSFRP3promoter methylation by methylation-specific polymerase chain reaction (MS-PCR) and bisulfite sequencing.SFRP3promoter methylation was observed in 100%, 60%, 39.1%, 16.2%, and 0% in HCC cell lines, primary HCCs, cirrhosis livers, chronic hepatitis livers, and control livers, respectively. Demethylation treatment with 5-aza-2′-deoxycytidine in HCC cells restored or increased theSFRP3mRNA expression. We next used quantitative MS-PCR (QMSP) to analyze the methylation level ofSFRP3in 60 HCCs and their corresponding nontumor tissues. Methylation ofSFRP3promoter region in HCCs increased significantly compared with control tissues. There is a positive correlation between promoter hypermethylation andSFRP3mRNA downregulation. Our data suggest that promoter hypermethylation ofSFRP3is a common event in HCCs and plays an important role in regulation ofSFRP3mRNA expression.

scholarly journals Analysis of smad4 gene promoter methylation in pancreatic and endometrial cancers

2017 ◽  
Vol 23 (2) ◽  
pp. 17-19
Author(s):  
Aleksandra Nikolic ◽  
Filip Opincal ◽  
Momcilo Ristanovic ◽  
Jovanka Trifunovic ◽  
Srbislav Knezevic ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Methylation Status ◽  
Gene Promoter ◽  
Promoter Hypermethylation ◽  
Surgical Removal ◽  
Smad4 Gene ◽  
Frequent Event ◽  
Cancer Types ◽  
Endometrial Cancers ◽  
Tumor Types

Background. Promoter hypermethylation of the SMAD4 gene has been registered in some cancer types, but in general doesn?t appear to be a frequent event in carcinogenesis. However, only a few published studies deal with this topic and not many cancer types have been analyzed. The aim of this study was to establish SMAD4 gene promoter methylation status in pancreatic and endometrial cancers. Methods. Patients included in the study (62 subjects) were diagnosed and surgically treated at the University of Belgrade, Clinical Center of Serbia. Patients with pancreatic carcinoma (17 subjects) underwent surgical removal of the pancreatic adenocarcinoma at the First Surgical Clinic, while the patients with endometrial carcinoma (45 subjects) underwent hysterectomy with adnexectomy at the Institute for Gynecology and Obstetrics. Extraction of DNA from fresh tissue samples was performed and the methylation status of the SMAD4 gene promoter was studied by a previously designed PCR-based HpaII and MspI restriction enzyme assay. The resulting PCR products were analyzed by electrophoresis in 2% agarose gels. Results. Neither of the analyzed samples was found to be hypermethylated. Conclusion. This is the first report on SMAD4 methylation status in pancreatic and endometrial tumor specimens, and supports the viewpoint that SMAD4 hypermethylation is not a common event in malignant tumors. Nevertheless, promoter hypermethylation remains a candidate mechanism for SMAD4 inactivation in malignant tissue as a potential cause of decreased or lost SMAD4 expression in certain tumor types, and should be further investigated in different tumor types and larger cohorts of patients.

scholarly journals EGCG Attenuates Renal Damage via Reversing Klotho Hypermethylation in Diabetic db/db Mice and HK-2 Cells

2020 ◽  
Vol 2020 ◽  
pp. 1-17 ◽  
Author(s):  
Xiu Hong Yang ◽  
Bao Long Zhang ◽  
Xiao Meng Zhang ◽  
Jin Dong Tong ◽  
Yan Hong Gu ◽  
...  
Keyword(s):  
Protein Expression ◽  
Promoter Methylation ◽  
Methylation Level ◽  
Dna Methyltransferase ◽  
Renal Damage ◽  
Transforming Growth Factor ◽  
Smooth Muscle Actin ◽  
Gene Promoter ◽  
Egcg Treatment ◽  
Klotho Gene

To explore whether epigallocatechin-3-gallate (EGCG) improves renal damage in diabetic db/db mice and high-glucose- (HG-) induced injury in HK-2 cells by regulating the level of Klotho gene promoter methylation. Western blotting was used to detect the protein expression levels of DNA methyltransferase 1 (DNMT1), DNMT3a, DNMT3b, transforming growth factor-β1 (TGF-β1), α-smooth muscle actin (α-SMA), and Klotho. The methylation level of the Klotho gene promoter was detected by pyrosequencing. Chromatin immunoprecipitation was used to detect the binding of the Klotho gene promoter to DNMT1 and DNMT3a. The expression of oxidative stress markers (reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), and 8-hydroxy-2′-deoxyguanosine (8-OHdG)) and inflammatory cytokines (interleukin-1β (IL-1β), IL-6, and tumor necrosis factor-α (TNF-α)) in kidney homogenates was also measured using ELISA. Klotho and DNMT3b protein expression was upregulated, while DNMT1, DNMT3a, TGF-β1, and α-SMA protein expression was downregulated after EGCG treatment. EGCG treatment also reduced the methylation level of the Klotho gene promoter as well as the binding of DNMT3a to the Klotho gene promoter. In addition, EGCG treatment significantly decreased the levels of ROS, MDA, 8-OHdG, IL-1β, IL-6, and TNF-α and increased the levels of CAT and SOD. Under HG conditions, EGCG regulated Klotho gene promoter methylation via DNMT3a and decreased the methylation level of the Klotho gene promoter, thereby upregulating the expression of the Klotho protein to exert its protective effect.

scholarly journals Thrombomodulin Is Silenced in Malignant Mesothelioma by a Poly(ADP-ribose) Polymerase-1-mediated Epigenetic Mechanism

2011 ◽  
Vol 286 (22) ◽  
pp. 19478-19488 ◽  
Author(s):  
Linda Nocchi ◽  
Marco Tomasetti ◽  
Monica Amati ◽  
Jiri Neuzil ◽  
Lory Santarelli ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Malignant Mesothelioma ◽  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Critical Role ◽  
Gene Promoter ◽  
Epigenetic Mechanism ◽  
Heterogeneous Expression ◽  
High Level

Malignant mesothelioma (MM) is often complicated by thromboembolic episodes, with thrombomodulin (TM) playing a critical role in the anticoagulant process. Heterogeneous expression of TM has been observed in cancer, and low or no TM expression in cancer cells is associated with poor prognosis. In this study, we analyzed TM expression in biopsies of MM patients and compared them with normal mesothelial tissue. The role of DNA methylation-associated gene silencing in TM expression was investigated. To evaluate poly(ADP-ribose) polymerase-1 (PARP1) as responsible for gene promoter epigenetic modifications, nonmalignant mesothelial cells (Met-5A) and MM cells (H28) were silenced for PARP1 and the DNA methylation/acetylation-associated TM expression evaluated. A correlation between low TM expression and high level of TM promoter methylation was found in MM biopsies. Low expression of TM was restored in MM cells by their treatment with 5-aza-2′-deoxycytidine and, to a lesser extent, with trichostatin, whereas the epigenetic agents did not affect TM expression in Met-5A cells. Silencing of PARP1 resulted in a strong down-regulation of TM expression in Met-5A cells, while restoring TM expression in H28 cells. PARP1 silencing induced TM promoter methylation in Met-5A cells and demethylation in MM cells, and this was paralleled by corresponding changes in the DNA methyltransferase activity. We propose that methylation of the TM promoter is responsible for silencing of TM expression in MM tissue, a process that is regulated by PARP1.

scholarly journals Growth Differentiation Factor-9 Stimulates Inhibin Production and Activates Smad2 in Cultured Rat Granulosa Cells

Endocrinology ◽  
2003 ◽  
Vol 144 (1) ◽  
pp. 172-178 ◽  
Author(s):  
Jae-Sook Roh ◽  
Jonas Bondestam ◽  
Sabine Mazerbourg ◽  
Noora Kaivo-Oja ◽  
Nigel Groome ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Granulosa Cells ◽  
Promoter Activity ◽  
Gene Promoter ◽  
Inhibin B ◽  
Inhibin A ◽  
Differentiation Factor ◽  
Growth Differentiation Factor 9 ◽  
Ovarian Inhibin ◽  
Stimulation Of

Abstract Ovarian inhibin production is stimulated by FSH and several TGFβ family ligands including activins and bone morphogenetic proteins. Growth differentiation factor-9 (GDF-9) derived by the oocyte is a member of the TGFβ/activin family, and we have previously shown that GDF-9 treatment stimulates ovarian inhibin-α content in explants of neonatal ovaries. However, little is known about GDF-9 regulation of inhibin production in granulosa cells and downstream signaling proteins activated by GDF-9. Here, we used cultured rat granulosa cells to examine the influence of GDF-9 on basal and FSH-stimulated inhibin production, expression of inhibin subunit transcripts, and the GDF-9 activation of Smad phosphorylation. Granulosa cells from small antral follicles of diethylstilbestrol-primed immature rats were cultured with FSH in the presence or absence of increasing concentrations of GDF-9. Secreted dimeric inhibin A and inhibin B were quantified using specific ELISAs, whereas inhibin subunit RNAs were analyzed by Northern blotting using 32P-labeled inhibin subunit cDNA probes. Similar to FSH, treatment with GDF-9 stimulated dose- and time-dependent increases of both inhibin A and inhibin B production. Furthermore, coincubation of cells with GDF-9 and FSH led to a synergistic stimulation of both inhibin A and inhibin B production. GDF-9 treatment also increased mRNA expression for inhibin-α and inhibin-β subunits. To investigate Smad activation, granulosa cell lysates were analyzed in immunoblots using antiphosphoSmad1 and antiphosphoSmad2 antibodies. GDF-9 treatment increased Smad2, but not Smad1, phosphorylation with increasing doses of GDF-9 leading to a dose-dependent increase in phosphoSmad2 levels. To further investigate inhibin-α gene promoter activation by GDF-9, granulosa cells were transiently transfected with an inhibin-α promoter-luciferase reporter construct and cultured with different hormones before assaying for luciferase activity. Treatment with FSH or GDF-9 resulted in increased inhibin-α gene promoter activity, and combined treatment with both led to synergistic increases. The present data demonstrate that oocyte-derived GDF-9, alone or together with pituitary-derived FSH, stimulates inhibin production, inhibin subunit mRNA expression, and inhibin-α promoter activity by rat granulosa cells. The synergistic stimulation of inhibin secretion by the paracrine hormone GDF-9 and the endocrine hormone FSH could play an important role in the feedback regulation of FSH release, thus leading to the modulation of follicle maturation and ovulation.

Efficacy and Tolerability of Temozolomide in an Alternating Weekly Regimen in Patients With Recurrent Glioma

2007 ◽  
Vol 25 (22) ◽  
pp. 3357-3361 ◽  
Author(s):  
Antje Wick ◽  
Jörg Felsberg ◽  
Joachim P. Steinbach ◽  
Ulrich Herrlinger ◽  
Michael Platten ◽  
...  
Keyword(s):  
Promoter Methylation ◽  
Dna Methyltransferase ◽  
Opportunistic Infections ◽  
Gene Promoter ◽  
Progression Free Survival ◽  
Preliminary Evidence ◽  
Recurrent Glioma ◽  
Hematologic Toxicity ◽  
Weekly Schedule ◽  
Mgmt Gene

Purpose Evaluation of toxicity and efficacy of an alternating weekly regimen of temozolomide administered 1 week on and 1 week off in patients with recurrent glioma. Patients and Methods Ninety adult patients with recurrent gliomas accrued in one center received chemotherapy with temozolomide at 150 mg/m2/d (days 1 through 7 and 15 through 21 every 4 weeks) with individual dose adjustments according to hematologic toxicity. Results A total of 906 treatment weeks were delivered. Grade 4 hematotoxicity according to the Common Terminology Criteria for Adverse Events (CTCAE; version 3.0) was observed in 24 treatment weeks (2.6%). CTCAE grade 4 lymphopenia eventually developed in 11 patients (12%). There were neither cumulative lymphopenias nor opportunistic infections. The progression-free survival (PFS) rate at 6 months for glioblastoma patients was 43.8%. The median PFS in these patients was 24 weeks (95% CI, 17 to 26 weeks), the median survival time from diagnosis of progression was 38 weeks (95% CI, 30 to 46 weeks), and the 1-year survival rate from progression was 23%. O6-methylguanine DNA methyltransferase (MGMT) gene promoter methylation in the tumor tissue was not associated with longer PFS (log-rank P = .37). Conclusion These data imply that the alternating weekly schedule is feasible, safe, and effective and clearly warrants investigation in randomized studies. Compared with more protracted low-dose temozolomide schedules, the 1-week-on/1-week-off schedule may be less toxic. We provide preliminary evidence that this dose-dense schedule is also active in patients with tumors lacking MGMT gene promoter methylation.

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