• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2719-2725
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• 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 Pacific Journal of Cancer Prevention
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• 제17권6호
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• pp.2757-2760
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• 2016

Gastric cancer (GC) is the fourth most prevalant cancer and the second leading cause of cancer-related mortality worldwide. As in other cancers gastric carcinogenesis is multifactorial involving environmental, genetic and epigenetic components. Epigenetic silencing due to hypermethylation of tumour suppressor genes is one of the key events in gastric carcinogenesis. This study was aimed to analyse the hypermethylation status of the E-Cadherin (CDH1) gene promoter in GCs in the ethnic Kashmiri population. In this study a total of 80 GC patients were recruited. Hypermethylation in tumour tissue was detected by methylation specific PCR (MS-PCR). Hypermethylation of CDH1 promoter was observed in 52 (65%) of gastric carcinoma cases which was significantly much higher than adjacent normal tissue [$p{\leq}0.0001$]. Further the frequency of CDH1 promoter methylation was significantly different with intestinal and diffuse types of gastric cancer [55.7% vs 82.1%; p<0.05]. Moreover females and cases with lymph node invasion had higher frequencies of CDH1 hypermethylation [$P{\leq}0.05$]. Thus the current data indicate a vital role of epigenetic alteration of CDH1 in the causation and development of gastric cancer, particularly of diffuse type, in our population.

• Tuberculosis and Respiratory Diseases
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• 제65권6호
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• pp.495-503
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• 2008

연구배경: 유전자의 후생적인 변화(epigenetic alteration)는 악성종양의 병인론에 있어서 유전자 변이와 동등한 위치를 점하고 있다. 특히 종양억제 유전자의 전사 촉진(promoter) 부위에 발생하는 비정상적인 메칠화(methylation)는 유전자의 발현을 침묵화(silencing)하고, 결과적으로 유전자의 기능 소실을 일으키게 된다. 저자들은 CpG island와 HpaII site를 가지고 있으며 암화 과정에 관여할 것으로 생각되는 유전자에 대하여 HpaII-MspI methylation microarray를 이용하여 새로운 종양억제 유전자를 발굴하고자 하였다. 방 법: 2005년 건양대학교 병원에서 수술한 비 소세포성 폐암 환자 10명에서 폐암조직과 상응하는 암 주변의 정상조직을 얻었으며, HpaII-MspI methylation microarray (Methyl-Scan DNA chip$^{(R)}$, Genomic tree, Inc, South Korea)를 이용하여 21개의 유전자에 대하여 DNA methylation profile을 분석하였다. 각각의 유전자에서 메칠화된 정도를 두 그룹에서 비교하였고, 정상 대조군으로 두 명의 젊고 건강한 기흉 환자에서 수술한 폐 조직에 대하여 methylation profile을 분석하였다. 결 과: 21개의 대상 유전자 중 10개의 유전자에서 폐암조직, 폐암 주변 정상 조직, 대조군에서 모두 공통적으로 과메칠화 되었고, 나머지 11개의 유전자 중 APC, AR, RAR-b, HTR1B, EPHA3, CFTR의 6개의 유전자에서 대조군에서 메칠화가 없으며, 폐암조직에서 폐암 주변 정상 조직에 비하여 더 빈번하게 과메칠화 되었다. 결 론: HTR1B, EPHA3, CFTR은 비소세포 폐암에서 후생적 변화로 발생하는 새로운 종양억제 유전자의 후보 유전자로서의 가능성이 있을 것으로 생각한다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권11호
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• pp.5799-5804
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• 2012

Family with sequence similarity 189, member B (FAM189B), alias COTE1, a putative oncogene selected by microarray, for the first time was here found to be significantly up-regulated in hepatocellular carcinoma (HCC) specimens and HCC cell lines. mRNA expression of COTE1 in HCC samples and cell lines was detected by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR, while protein expression of COTE1 in HCC tissues was assessed by immunohistochemistry. In addition, invasion of HCC cells was observed after overexpressing or silencing COTE1. In the total of 48 paired HCC specimens, compared with the adjacent non-cancer tissues, the expression of COTE1 was up-regulated in 31 (p<0.01). In HCC cell lines, COTE1 expression was significantly higher than in normal human adult liver (p<0.01). Overexpression of COTE1 enhanced HCC-derived LM6 and MHCC-L cellular invasion in vitro. In contrast, COTE1 knockdown via RNAi markedly suppressed these phenotypes, as documented in LM3 and MHCC-H HCC cells. Mechanistic analyses indicated that COTE1 could physically associate with WW domain oxidoreductase (WWOX), a tumor suppressor. COTE1 may be closely correlated with invasion of hepatocellular carcinoma (HCC) cells and thus may serve as an effective target for gene therapy.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1833-1836
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• 2012

Objective: Promoter methylation, which can be regulated by MTHFR activity, is associated with silencing of genes. In this study we evaluated the methylation status (type) of the BRCA2 promoter in ovarian cancer patients carrying different genotypes of the MTHFR gene (A or C polymorphisms at position 1298). Methods: The methylation type of the BRCA2 promoter was evaluated using bisulfate-modified DNA in methylation-specific PCR and the MTHFRa1278c polymorphism was assessed by PCR-RFLP. Results: Analysis of the BRCA2 promoter methylation type of cases showed that 7 out of 60 cases (11.7%) were methylated while the remaining 53 (88.3%) were unmethylated. In methylated cases, one out of the 7 cases had a CC genotype and the remaining 6 methylated cases had an AC genotype. The AA genotype was absent. In unmethylated cases, 34, 18, and one out of these had AC, AA and CC genotype, respectively. Conclusion: There was no significant relationship between the methylation types of the BRCA2 promoter in different genotypes of MTHFRa1298c polymorphism in ovarian cancer; p=0.255. There was no significant relation between the methylation types of the BRCA2 promoter in different genotypes of the MTHFRa1298c polymorphism in ovarian cancer.

• Asian Pacific Journal of Cancer Prevention
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• 제17권sup3호
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• pp.219-224
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• 2016

Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver making up more than 80 percent of cases. It is known to be the sixth most prevalent cancer and the third most frequent cause of cancer related death worldwide. Epigenetic regulation constitutes an important mechanism by which dietary components can selectively activate or inactivate target gene expression. The miR-34 family members including mir-34a, mir-34b and mir-34c are tumor suppressor micro RNAs, which are expressed in the majority of normal tissues. Several studies have indicated silencing of miR-34 expression via DNA methylation in multiple types of cancers. Bioactive nutrients like curcumin (Cur) have excellent anticarcinogenic activity and minimal toxic manifestations in biological systems. This compound has recently been determined to induce epigenetic changes. However, Cur is lipophilic and has a poor systemic bioavailability and poor absorption. Its bioavailability is increased through employing dendrosome nanoparticles. The aim of the current study was to investigate the effect of dendrosomal nanocurcumin (DNC) on expression of mir-34 family members in two HCC cell lines, HepG2 and Huh7. We performed the MTT assay to evaluate DNC and dendrosome effects on cell viability. The ability of DNC to alter expression of the mir-34 family and DNA methyltransferases (DNMT1, DNMT3A and 3B) was evaluated using semi-quantitative and quantitative PCR. We observed the entrance of DNC into HepG2 and Huh7 cells. Gene expression assays indicated that DNC treatment upregulated mir34a, mir34b and mir34c expression (P<0.05) as well as downregulated DNMT1, DNMT3A and DNMT3B expression (P<0.05) in both HepG2 and Huh7 cell lines. DNC also reduced viability of Huh7 and HepG2 cells through restoration of miR-34s expression. We showed that DNC could awaken the epigenetically silenced miR-34 family by downregulation of DNMTs. Our findings suggest that DNC has potential in epigenetic therapy of HCC.

• 생명과학회지
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• 제18권8호
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• pp.1132-1139
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• 2008

CpG island는 유전자의 발현 기작과 많은 관련이 있다. 포유동물 유전자의 약 $30{\sim}60$% 정도의 프로모터와 엑손부위에 CpG island가 존재 한다. 최근의 연구 결과에 따르면 CpG island의 과메틸화는 주요 암 억제유전자들을 불활성화 시켜 암을 일으키는 주요 요인이 되는 것으로 밝혀졌다. CpG island의 과메틸화는 거의 모든 암 종류에서 발견되고 있다. 따라서 CpG island를 검색하는 프로그램은 매우 중요한 의미를 갖는다. 그래서 D. Takai 와 P. A. Jones 등이 2002년 검증한 CpG island 정의 기준을 이용하여 윈도우 기반의 소프트웨어 프로그램인 CpGi를 개발하였다. CpGi는 Visual C++ 6.0로 구현하였으며, 입력서열 양식은 FASTA 포맷을 허용하도록 구성하였다. CpGi의 검색 성능을 평가하기 위해 2개의 인간 Contig, 즉, AP00524 (22번 염색체)와 NT_029490.3 (21번 염색체) 등을 대상으로 기존의 다른 CpG island 검색 프로그램인 Emboss-CpGPlot 및 CpG Island Searcher 등과 검색결과를 비교 분석하였다. CpGi에 의한 검색 결과는 다른 두 프로그램에 비해 같거나 오히려 보다 정확한 검색 결과를 보여주었다. CpGi는 사용자 친화적인 윈도우 인터페이스로 구현되어 있어 사용자가 프로그램을 구동하고 이용하기 매우 쉽고, 분석결과에 대한 이해도 용이하다. 본 프로그램은 사용자가 지정한 파라미터 값들(%GC, Obs (CpG)/Exp (CpG), 분석 윈도우 크기, 스텝크기, Gap 허용치, #CG)에 의해 CpG island의 위치를 결정하고, G+C%와 CpG island의 위치를 시각적으로 보여준다. 결과적으로, CpGi는 CpG island 관련 실험 연구자들뿐만 아니라 대용량 서열 분석 및 주석 작업을 위해 매우 유용한 도구로 활용될 수 있을 것이다.