• Journal of Embryo Transfer
• /
• v.23 no.3
• /
• pp.133-139
• /
• 2008

DNA methylation is one of the reasons for poor survival of clone animals. The OCT-4 gene is essential for maintaining pluripotency of embryonic stem (ES) cells and early embryos. We previously reported that the 5'-promoter region of Oct-4 gene was a target of DNA methylation and the methylation status was changed variously during embryonic development in bovine. The study conducted to examine the expression and methylation pattern of tissue-dependent differentially methylated region (T-DMR) of Oct-4 gene in bovine somatic cell nuclear transfer (SCNT) and in vitro fertilization (IVF) blastocysts. The Oct-4 gene expression was evaluated by RT-PCR and fluorescence immunocytochemistry. The methylation pattern of T-DMR was analyzed using restriction mapping and bisulfite sequencing methods. The Oct-4 transcripts were highly expressed in IVF, while they were not expressed in SCNT. The Oct-4 protein was not detected or expressed at very low level in SCNT, the intensity of Oct-4 protein, however, was strong in IVF. On the other hand, the T-DMR of Oct-4 gene was hypermethylated in SCNT compared to that of IVF. These results suggested that expression and the failure of demethylation of Oct-4 gene was closely associated with incomplete development of SCNT embryos.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.6
• /
• pp.2719-2725
• /
• 2014

Background: Secreted frizzled-related protein (SFRP) genes, new tumor suppressor genes, are negative regulators of the Wnt pathway whose alteration is associated with various tumors. In ovarian cancer, SFRPs genes promoter methylation can lead to gene inactivation. This study investigated mechanisms of SFRP and adenomatous polyposis coli (APC) genes silencing in ovarian cancer infected with high risk human papillomavirus. Materials and Methods: DNA was extracted from 200 formalin-fixed paraffin-embedded ovarian cancer and their normal adjacent tissues (NAT) and DNA methylation was detected by methylation specific PCR (MSP). High risk human papillomavirus (HPV) was detected by nested PCR with consensus primers to amplify a broad spectrum of HPV genotypes. Results: The percentages of SFRP and APC genes with methylation were significantly higher in ovarian cancer tissues infected with high risk HPV compared to NAT. The methylated studied genes were associated with suppression in their gene expression. Conclusion: This finding highlights the possible role of the high risk HPV virus in ovarian carcinogenesis or in facilitating cancer progression by suppression of SFRP and APC genes via DNA methylation.

• Asian-Australasian Journal of Animal Sciences
• /
• v.29 no.7
• /
• pp.1037-1043
• /
• 2016

Epigenetic processes in the development of skeletal muscle have been appreciated for over a decade. DNA methylation is a major epigenetic modification important for regulating gene expression and suppressing spurious transcription. Up to now, the importance of epigenetic marks in the regulation of Pax7 and myogenic regulatory factors (MRFs) expression is far less explored. In the present study, semi-quantitative the real-time polymerase chain reaction (RT-PCR) analyses showed MyoD and Myf5 were expressed in activated and quiescent C2C12 cells. MyoG was expressed in a later stage of myogenesis. Pax7 was weakly expressed in differentiated C2C12 cells. To further understand the regulation of expression of these genes, the DNA methylation status of Pax7, MyoD, and Myf5 was determined by bisulfite sequencing PCR. During the C2C12 myoblasts fusion process, the changes of promoter and exon 1 methylation of Pax7, MyoD, and Myf5 genes were observed. In addition, an inverse relationship of low methylation and high expression was found. These results suggest that DNA methylation may be an important mechanism regulating Pax7 and MRFs transcription in cell myogenic differentiation.

• Asian Pacific Journal of Cancer Prevention
• /
• v.17 no.5
• /
• pp.2727-2728
• /
• 2016

• BMB Reports
• /
• v.45 no.2
• /
• pp.126-131
• /
• 2012

We have previously identified a DNA silent region located downstream of the 3'-end of the ${\beta}^{major}$ globin gene (designated B1-559) that contains a B1 retrotransposon, consensus binding sites for erythroid specific transcription factors and shares the capacity to act as promoter in hematopoietic cells interacting with ${\beta}$-globin gene LCR sequences in vitro. In this study, we have cloned four new non-polyA RNA transcripts being detected upon blockade of murine erythroleukemia (MEL) cell differentiation to erythroid maturation by methylation inhibitors and demonstrated that two of them share high structural homology with sequences of B1 element found within the B1-559 region. Although it is not clear yet whether and how these RNAs interfere with induction of erythroid maturation, these data provide evidence for the first time showing that methylation inhibitors can activate silent repetitive DNA sequences in MEL cells and may have implications in cancer chemotherapy using demethylating drugs as antineoplastic agents.

• Journal of Gastric Cancer
• /
• v.21 no.4
• /
• pp.379-391
• /
• 2021

Purpose: Promoter DNA methylation of various genes has been associated with metachronous gastric cancer (MGC). The cancer-specific methylation gene, cysteine dioxygenase type 1 (CDO1), has been implicated in the occurrence of residual gastric cancer. We evaluated whether DNA methylation of CDO1 could be a predictive biomarker of MGC using specimens of MGC developing on scars after endoscopic submucosal dissection (ESD). Materials and Methods: CDO1 methylation values (TaqMeth values) were compared between 33 patients with early gastric cancer (EGC) with no confirmed metachronous lesions at >3 years after ESD (non-MGC: nMGC group) and 11 patients with MGC developing on scars after ESD (MGCSE groups: EGC at the first ESD [MGCSE-1 group], EGC at the second ESD for treating MGC developing on scars after ESD [MGCSE-2 group]). Each EGC specimen was measured at five locations (at tumor [T] and the 4-point tumor-adjacent noncancerous mucosa [TAM]). Results: In the nMGC group, the TaqMeth values for T were significantly higher than that for TAM (P=0.0006). In the MGCSE groups, TAM (MGCSE-1) exhibited significantly higher TaqMeth values than TAM (nMGC) (P<0.0001) and TAM (MGCSE-2) (P=0.0041), suggesting that TAM (MGCSE-1) exhibited CDO1 hypermethylation similar to T (P=0.3638). The area under the curve for discriminating the highest TaqMeth value of TAM (MGCSE-1) from that of TAM (nMGC) was 0.81, and using the cut-off value of 43.4, CDO1 hypermethylation effectively enriched the MGCSE groups (P<0.0001). Conclusions: CDO1 hypermethylation has been implicated in the occurrence of MGC, suggesting its potential as a promising MGC predictor.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.1
• /
• pp.181-186
• /
• 2012

The aim of this study was to evaluate the methylation status of three important cancer related genes viz. p16, E-cadherin and hMLH1 promoters and to associate the findings with specific dietary habits in Kashmiris, a culturally distinct population in India, with gastric cancer. The study subjects were divided into three age groups viz. 0-30yrs ($1^{st}$), 31-60yrs ($2^{nd}$) and 61-90yrs ($3^{rd}$). A highly significant association between the intake of local hot salted tea in $2^{nd}$ (p=0.001) and $3^{rd}$ (p=0.009) age groups was observed with the promoter hypermethylation of E cadherin. Again a highly significant association between the aberrant methylation of hMLH1 (p=0.000) and p16 (p=0.000) promoters and the intake of local hot salted tea was observed in the $2^{nd}$ age group of gastric cancer patients. The intake of sun-dried food was also significantly associated with the promoter hypermethylation of E cadherin (p=0.003) and p16 (p=0.015) genes in $3^{rd}$ age group. The results of the present study suggest a close association between the aberrant methylation of p16, E-cadherin and hMLH1 promoters and the intake of local hot salted tea and sun-dried foods in Kashmiri population.

• BMB Reports
• /
• v.49 no.3
• /
• pp.167-172
• /
• 2016

Kaiso is a Pox Virus and Zinc Finger (POZ-ZF) transcription factor with bi-modal DNA-binding specificity. Here, we demonstrated that Kaiso expression is inversely correlated with glucocorticoid receptor (GR) expression in breast carcinomas. Knockdown of Kaiso increased GR expression, while overexpression of Kaiso inhibited GR expression in breast cancer cells. Furthermore, Kaiso repressed GR proximal promoter-reporter activity in a dose-dependent manner. Remarkably, ChIP experiments demonstrated that endogenous Kaiso was associated with the GR promoter sequence in a methylation-dependent manner. Since glucocorticoids inhibit chemotherapyinduced apoptosis and have been widely used as a co-treatment of patients with breast cancer, we assessed the role of Kasio in GR-mediated anti-apoptotic effects. We found that overexpression of Kaiso attenuated the anti-apoptotic effects of glucocorticoids in breast cancer cells. Our findings suggest that GR is a putative target gene of Kaiso and suggest Kaiso to be a potential therapeutic target in GC-combination chemotherapy in breast cancer.

• Asian Pacific Journal of Cancer Prevention
• /
• v.15 no.22
• /
• pp.9607-9610
• /
• 2014

Breast cancer, a leading cause of death among women in most countries worldwide, is rapidly increasing in incidence in Vietnam. One of biomarkers is the disruption of the genetic material including epigenetic changes like DNA methylation. With the aim of finding hypermethylation at CpG islands of promoter of BRCA1 gene, belonged to the tumor suppressor gene family, as the biomarker for breast cancer in Vietnamese population, sensitive methyl specific PCR (MSP) was carried out on 115 samples including 95 breast cancer specimens and 20 normal breast tissues with other diseases which were obtained from Ho Chi Minh City Medical Hospital, Vietnam. The result indicated that the frequency of BRCA1 hypermethylation reached 82.1% in the cases (p<0.001). In addition, the DNA hypermethylation of this candidate gene increased the possibility to be breast cancer with high incidence via calculated odd ratios (p<0.05). In conclusion, hypermethylation of this candidate gene could be used as the promising biomarker application with Vietnamese breast cancer patients.

• Molecules and Cells
• /
• v.40 no.1
• /
• pp.45-53
• /
• 2017

Aberrant hypermethylation of Wnt antagonists has been observed in gastric cancer. A number of studies have focused on the hypermethylation of a single Wnt antagonist and its role in regulating the activation of signaling. However, how the Wnt antagonists interacted to regulate the signaling pathway has not been reported. In the present study, we systematically investigated the methylation of some Wnt antagonist genes (SFRP2, SFRP4, SFRP5, DKK1, DKK2, and APC) and their regulatory role in carcinogenesis. We found that aberrant promoter methylation of SFRP2, SFRP4, DKK1, and DKK2 was significantly increased in gastric cancer. Moreover, concurrent hypermethylation of SFRP2 and DKK2 was observed in gastric cancer and this was significantly associated with increased expression of ${\beta}-catenin$, indicating that the joint inactivation of these two genes promoted the activation of the Wnt signaling pathway. Further analysis using a multivariate Cox proportional hazards model showed that DKK2 methylation was an independent prognostic factor for poor overall survival, and the predictive value was markedly enhanced when the combined methylation status of SFRP2 and DKK2 was considered. In addition, the methylation level of SFRP4 and DKK2 was correlated with the patient's age and tumor differentiation, respectively. In conclusion, epigenetic silencing of Wnt antagonists was associated with gastric carcinogenesis, and concurrent hypermethylation of SFRP2 and DKK2 could be a potential marker for a prognosis of poor overall survival.