• 한국수정란이식학회지
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• 제23권3호
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• pp.133-139
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• 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.

• Reproductive and Developmental Biology
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• 제31권2호
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• pp.97-102
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• 2007

The objective of this study was to analyzed pattern of proteins expression abnormally in cloned bovine placenta. TIMP-2 protein whose function is related to extracellular matrix degradation and tissue remodeling processes was one of differentially up-regulated proteins in SCNT placenta. And one of down-regulated protein in SCNT placenta was identified as vimentin protein that is presumed to stabilize the architecture of the cytoplasm. The expression patterns of these proteins were validated by Western blotting. To evaluate how regulatory loci. of TIMP-2 and vimentin genes was programmed reprogramming in cloned placenta. the status of DNA methylation in the promoter region of TIMP-2 and vimentin genes was analyzed by sodium Bisulfite mapping. The DNA methylation results showed that there was not difference in methylation pattern of TIMP-2 and vimentin loci between cloned and normal placenta. Histone H3 acetylation state of the nucleosome was analyzed in the cloned placental and normal placenta by Western blotting. A small portion of the protein lysates were subjected to Western blotting with the antibodies against anti acetyl-Histone H3. Overall histone H3 acetylation state of SCNT placenta was significantly higher than those of normal placenta cells. It is postulated that cloned placenta at the end of gestation seems to be unusual in function and morphology of placenta via improper expression of TIMP-2 and vimentin by abnormal acetylation states of cloned genome.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권2호
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• pp.164-173
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• 2000

The p16 protein is a cyclin dependent kinase inhibitor that inhibits cell cycle progression from $G_1$ phase to S phase in cell cycle. Many p16 gene mutations have been noted in many cancer-cell lines and in some primary cancers, and alterations of p16 gene function by DNA methylation have been noticed in various kinds of cancer tissues and cell-lines. There have been a large body of literature has accumulated indicating that abnormal patterns of DNA methylation (both hypomethylation and hypermethylation) occur in a wide variety of human neoplasma and that these aberrations of DNA methylation may play an important epigenetic role in the development and progression of neoplasia. DNA methylation is a part of the inheritable epigenetic system that influences expression or silencing of genes necessary for normal differentiation and proliferation. Gene activity may be silenced by methylation of up steream regulatory regions. Reactivation is associated with demethylation. Although evidence or a high incidence of p16 alterations in a variety of cell lines and primary tumors has been reported, that has been contested by other investigators. The precise mechanisms by which abnormal methylation might contribute to carcinogenesis are still not fully elucidated, but conceivably could involve the modulation of oncogene and other important regulatory gene expression, in addition to creating areas of genetic instability, thus predisposing to mutational events causing neoplasia. There have been many variable results of studies of head and neck squamous cell carcinoma(HNSCC). This investigation was studied on 13 primary HNSCC for p16 gene status by protein expression in immunohistochemistry, and DNA genetic/epigenetic analyzed to determine the incidence, the mechanisms, and the potential biological significance of its Inactivation. As methylation detection method of p16 gene, the methylation specific PCR(MSP) is sensitive and specific for methylation of any block of CpG sites in a CpG islands using bisulfite-modified DNA. The genomic DNA is modified by treatment with sodium bisulfate, which converts all unmethylated cytosines to uracil(thymidine). The primers designed for MSP were chosen for regions containing frequent cytosines (to distinguish unmodified from modified DNA), and CpG pairs near the 5' end of the primers (to provide maximal discrimination in the PCR between methylated and unmethylated DNA). The two strands of DNA are no longer complementary after bisulfite treatment, primers can be designed for either modified strand. In this study, 13 paraffin embedded block tissues were used, so the fragment of DNA to be amplified was intentionally small, to allow the assessment of methylation pattern in a limited region and to facilitate the application of this technique to samlples. In this 13 primary HNSCC tissues, there was no methylation of p16 promoter gene (detected by MSP and automatic sequencing). The p16 protein-specific immunohistochemical staining was performed on 13 paraffin embedded primary HNSCC tissue samples. Twelve cases among the 13 showed altered expression of p16 proteins (negative expression). In this study, The author suggested that low expression of p16 protein may play an important role in human HNSCC, and this study suggested that many kinds of genetic mechanisms including DNA methylation may play the role in carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• 제16권13호
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• pp.5343-5348
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• 2015

Promoter hypermethylation of the runt-related transcription factor 3 (RUNX3) gene is associated with increased risk of hepatocellular carcinoma (HCC). Oxidative stress plays a vital role in both carcinogenesis and progression of HCC. However, whether oxidative stress and RUNX3 hypermethylation in HCC have a cause-and-effect relationship is not known. In this study, plasma protein carbonyl and total antioxidant capacity (TAC) in patients with hepatitis B virus (HBV)-associated HCC (n=60) and age-matched healthy subjects (n=80) was determined. RUNX3 methylation in peripheral blood mononuclear cells (PBMC) of subjects was measured by methylation-specific PCR. Effect of reactive oxygen species (ROS) on induction of RUNX3 hypermethylation in HCC cells was investigated. Plasma protein carbonyl content was significantly higher, whereas plasma TAC was significantly lower, in HCC patients than healthy controls. Based on logistic regression, increased plasma protein carbonyl and decreased plasma TAC were independently associated with increased risk for HCC. PBMC RUNX3 methylation in the patient group was significantly greater than in the healthy group. RUNX3 methylation in hydrogen peroxide ($H_2O_2$)-treated HepG2 cells was significantly higher than in untreated control cells. In conclusion, increase in oxidative stress in Thai patients with HBV-associated HCC was demonstrated. This oxidative increment was independently associated with an increased risk for HCC development. RUNX3 in PBMC was found to be hypermethylated in the HCC patients. In vitro, RUNX3 hypermethylation was experimentally induced by $H_2O_2$. Our findings suggest that oxidative stress is a cause of RUNX3 promoter hypermethylation in HCC cells.

• Asian Pacific Journal of Cancer Prevention
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• 제16권2호
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• pp.541-549
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• 2015

Triple negative breast cancer (TNBC) is an aggressive subtype of breast cancer (BC) with higher metastatic rate and both local and systemic recurrence compared to non-TNBC. The generation of reactive oxygen species (ROS) secondary to oxidative stress is associated with DNA damage, chromosomal degradation and alterations of both hypermethylation and hypomethylation of DNA. This study concerns differential methylation of promoter regions in specific groups of genes in TNBC and non-TNBC Saudi females in an effort to understand whether epigenetic events might be involved in breast carcinogenesis, and whether they might be used as markers for Saudi BCs. Methylation of glutathione S-transferase P1 (GSTP1), T-cadherin (CDH13), Paired box protein 5 (PAX5), death associated protein kinase (DAPK), twist-related protein (TWIST), DNA-binding protein inhibitor (ID4), High In Normal-1 (HIN-1), cyclin-dependent kinase inhibitor 2A (p16), cyclin D2 and retinoic acid receptor-${\beta}$ ($RAR{\beta}1$) genes was analyzed by methylation specific polymerase chain reaction (MSP) in 200 archival formalin-fixed paraffin embedded BC tissues divided into 3 groups; benign breast tissues (20), TNBC (80) and non-TNBC (100). The relationships between methylation status, and clinical and pathological characteristics of patients and tumors were assessed. Higher frequencies of GSTP1, ID4, TWIST, DAPK, PAX5 and HIN-1 hypermethylation were found in TNBC than in non-TNBC. Hypermethylation of GSTP1, CDH13, ID4, DAPK, HIN-1 and PAX5 increased with tumor grade increasing. Other statistically significant correlations were identified with studied genes. Data from this study suggest that increased hypermethylation of GSTP1, ID4, TWIST, DAPK, PAX5 and HIN-1 genes in TNBC than in non-TNBC can act as useful biomarker for BCs in the Saudi population. The higher frequency of specific hypermethylated genes paralleling tumor grade, size and lymph node involvement suggests contributions to breast cancer initiation and progression.

• Journal of Gastric Cancer
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• 제5권4호
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• pp.228-237
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• 2005

목적: 위암조직에서 P16과 hMLH1 유전자의 메틸화상태를 검사하여 위암의 발생과정에서의 작용과 유전자의 발현에 미치는 영향과 Helicobacter paylori균 감염여부 및 임상병리학적인자와의 연관성을 알아보고자 하였다. 대상 및 방법: 위암 신선 동결 절편조직 100예를 대상으로 유전자의 단백질 발현상태는 면역조직화학 염색을 시행하여 확인하였고. 메틸화 상태는 methylation-specific PCR(MSP)과 염기서열분석을 시행하였다. 결과: P16유전자의 메틸화는 19예(19%)에서 관찰되었고 이 중 18예(94.7%)에서 P16유전자의 단백질 발현 소실이 있어, P16 유전자의 단백질 발현 소실이 P16유전자의 메틸화와 연관이 있음을 알 수 있었다(kappa 계수=0.317, P=.0011). hMLH1 유전자의 메틸화는 27예(27%)에서 관찰되었고, 이 중 24예(8.8%)에서 hMLH1 단백의 소실이 hMLH1유전자의 메틸화와 연관이 있음을 보여주었다(kappa계수=0.675, p<0.0001). hMLH1 유전자의 메틸화는 나이, 암종의 크기, Lauren 분류와 연관성이 있었다. P16 유전자와 hMLH1 유전자 메틸화 모두 Helicobacter paylori균 감염여부와는 연관성이 없었다. 결론: 위암에서 P16 및 hMLH1 유전자의 불활성화에는 DNA 메틸화가 작용을 함을 알 수 있었고, hMLH1유전자의 메틸화는 나이, 암종의 크기, Lauren 분류와 연관이 있음을 알 수 있었다.

• 한국동물번식학회:학술대회논문집
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• 한국동물번식학회 2003년도 학술발표대회 발표논문초록집
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• pp.27-27
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• 2003

A diversified and concentrative approach of methylation player can be one of the most powerful studies in the understanding of global epigenetic modifications. Previous studies have suggested that DNA methylation contributes to transcriptional silencing through the several DNA methylation-mediated repression systems by hypermethylation, including methyltransferases (DNMTs), DNA methyltransferase association protein 1 (DMAPl), methyl-CpG binding domain (MBD), and histone deacetylases (HDACs). Assembly of these regulatory protein complexes act sequentially, reciprocally, and interdependently on the newly composed DNA strand through S phase. Therefore, these protein complexes have a role in coupling DNA replication to the designed turn-off system in genome. In this study, we attempted to address the role of DNA methylation by the functional analysis of the methyltransferase molecule, we described the involvement of DMAP1 and DNMTs in cell divistion and the effect of their loss. We also described distinct patterns that DMAP1 and DNMTs are spatially reorganized and displaced from condensing chromosomes as cells progress through mitosis in HeLa cell, COS7, and HIH3T3 cell cycle progressions. DNMT1, DNMT3b, and DMAP1 do not stably contact the genetic material during chromosome compaction and repressive expression. These finding show that the loss of activities of DNMTs and DMAP1 occure stage specifically during the cell cycle, may contribute to the integral balance of global DNA methylation. This is consistent with previous studies resulted in decreased histone acetyltransferases and HDACs, and differs from studies resulted in increased histone methyltransferases. Our results suggest that DNA methylation by DNMTs and DMAP1 during mitosis acts to antagonize hypermethylation by which this mark is epigenetical mitotic-specific methylation.

• Asian Pacific Journal of Cancer Prevention
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• 제15권1호
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• pp.355-362
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• 2014

Objective: Altered regulation of many transcription factors has been shown to play important roles in the development of leukemia. hMSH2 can modulate the activity of some important transcription factors and is known to be a regulator of hematopoietic differentiation. Herein, we investigated epigenetic regulation of hMSH2 and its influence on cell growth and overall survival of acute lymphoblastic leukemia (ALL) patients. Methods: hMSH2 promoter methylation status was assessed by COBRA and pyrosequencing in 60 ALL patients and 30 healthy volunteers. mRNA and protein expression levels of hMSH2, PCNA, CyclinD1, Bcl-2 and Bax were determined by real time PCR and Western blotting, respectively. The influence of hMSH2 on cell proliferation and survival was assessed in transient and stable expression systems. Results: mRNA and protein expression of hMSH2 and Bcl-2 was decreased, and that of PCNA, CyclinD1 and Bax was increased in ALL patients as compared to healthy volunteers (P<0.05). hMSH2 was inactivated in ALL patients through promoter hypermethylation. Furthermore, hMSH2 hypermethylation was found in relapsed ALL patients (85.7% of all cases). The median survival of patients with hMSH2 methylation was shorter than that of patients without hMSH2 methylation (log-rank test, P=0.0035). Over-expression of hMSH2 in cell lines resulted in a significant reduction in growth and induction of apoptosis. Conclusions: This study suggests that aberrant DNA methylation and epigenetic inactivation of hMSH2 play an important role in the development of ALL through altering cell growth and survival.

• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2485-2489
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• 2014

In the present study, we studied the hypermethylation of the human riboflavin transporter 2 (hRFT2) gene and regulation of protein expression in biopsies from resected tissues from Uighur cervical squamous cell carcinoma (CSCC) patients and their neighboring normal tissues. hRFT2 gene promoter region methylation sequences were mapped in cervical cancer cell line SiHa by bisulfite-sequencing PCR and quantitative detection of methylated DNA from 30 pairs of Uighur's CSCCs and adjacent normal tissues by MassARRAY (Sequenom, San Diego, CA, USA) and hRFT2 protein expression was analyzed by immunohistochemistry. In SiHa, we identified 2 CG sites methylated from all of 12CpG sites of the hRFT2 gene. Analysis of the data from quantitative analysis of single CpG site methylation by Sequenom MassARRAY platform showed that the methylation level between two CpG sites (CpG 2 and CpG 3) from CpG 1~12 showed significant differences between CSCC and neighboring normal tissues. However, the methylation level of whole target CpG fragments demonstrated no significant variation between CSCC ($0.476{\pm}0.020$) and neighboring normal tissues ($0.401{\pm}0.019$, p>0.05). There was a tendency for translocation the hRFT2 proteins from cytoplasm/membrane to nucleus in CSCC with increase in methylation of CpG 2 and CpG 3 in hRFT2gene promoter regions, which may relate to the genesis of CSCC. Our results suggested that epigenetic modifications are responsible for aberrant expression of the hRFT2 gene, and may help to understand mechanisms of cervical carcinogenesis.

• Tuberculosis and Respiratory Diseases
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• 제51권2호
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• pp.108-121
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• 2001

배 경 : p16 종양 억제 유전자 promoter의 aberrant methylation에 의한 불활성화가 비소세포 폐암이 발병하는 초기단계에 영향을 미치는 것으로 추측되며, DAP kinase 유전자 promoter의 hypermethylation은 유전자의 발현을 억제하여 폐암의 전이에 중요한 역할을 한다고 알려져 있다. 방 법 : 본 연구는 비소세포 폐암으로 근치적 절제술을 받은 환자 중에서 총 35 예를 대상으로 MSP률 이용하여 p16 유전자와 DAP kinase의 비정상적인 methylation의 양상을 조사하여, 폐암에서 두 유전자의 메틸화 빈도, 진단적 응용의 가능성 빛 임상적 유용성을 알고자 하였다. 결 과 : 전체 대상 35예중 p16 유전자의 aberrant methylation은 33예중 13예(39.4%)에서, DAP kinase 유전자 hypermethylation은 35예중 21예(60%)에서 확인할 수 있었다. 55 세 이상에서 p16의 aberrant methylation은 유의하게 증가되어 있었으며, DAP kinase는 병기의 진행도에 따라 발현 빈도가 증가하였으나, 통계학적 의미는 없었다. 또한 p16 유전자와 DAP kinase 유전자간의 메틸화 양상에서도 연관성은 관찰할 수 없었다. 결 론 : p16과 DAP kinase 유전자중 하나라도 비정상적인 메틸화가 발견된 경우는 전체 대상의 74.3% 로 비교적 높은 빈도로 관찰되어 폐암의 조기 진단을 위한 분자 생물학적 방법으로 이용될 수 있을 것으로 사료된다.