• Experimental and Molecular Medicine
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• 제50권12호
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• pp.1.1-1.14
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• 2018

DNA methylation is a regulatory mechanism in epigenetics that is frequently altered during human carcinogenesis. To detect critical methylation events associated with gastric cancer (GC), we compared three DNA methylomes from gastric mucosa (GM), intestinal metaplasia (IM), and gastric tumor (GT) cells that were microscopically dissected from an intestinal-type early gastric cancer (EGC) using methylated DNA binding domain sequencing (MBD-seq) and reduced representation bisulfite sequencing (RRBS) analysis. In this study, we focused on differentially methylated promoters (DMPs) that could be directly associated with gene expression. We detected 2,761 and 677 DMPs between the GT and GM by MBD-seq and RRBS, respectively, and for a total of 3,035 DMPs. Then, 514 (17%) of all DMPs were detected in the IM genome, which is a precancer of GC, supporting that some DMPs might represent an early event in gastric carcinogenesis. A pathway analysis of all DMPs demonstrated that 59 G protein-coupled receptor (GPCR) genes linked to the hypermethylated DMPs were significantly enriched in a neuroactive ligand-receptor interaction pathway. Furthermore, among the 59 GPCRs, six GI hormone receptor genes (NPY1R, PPYR1, PTGDR, PTGER2, PTGER3, and SSTR2) that play an inhibitory role in the secretion of gastrin or gastric acid were selected and validated as potential biomarkers for the diagnosis or prognosis of GC patients in two cohorts. These data suggest that the loss of function of gastrointestinal (GI) hormone receptors by promoter methylation may lead to gastric carcinogenesis because gastrin and gastric acid have been known to play a role in cell differentiation and carcinogenesis in the GI tract.

• Asian Pacific Journal of Cancer Prevention
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• 제15권6호
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• pp.2753-2758
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• 2014

Background: GC-binding factor 2 (GCF2) is a transcriptional regulator that represses transcriptional activity of the epidermal growth factor receptor (EGFR) by binding to a specific GC-rich sequence in the EGFR gene promoter. In addition to this function, GCF2 has also been identified as a tumor-associated antigen and regarded as a potentially valuable serum biomarker for early human hepatocellular carcinoma (HCC) diagnosis. GCF2 is high expressed in most HCC tissues and cell lines including HepG2. This study focused on the influence of GCF2 on cell proliferation and apoptosis in HepG2 cells. Materials and Methods: GCF2 expression at both mRNA and protein levels in HepG2 cells was detected with reverse transcription (RT) PCR and Western blotting, respectively. RNA interference (RNAi) technology was used to knock down GCF2 mRNA and protein expression. Afterwards, cell viability was analyzed with a Cell Counting Kit-8 (CCK-8), and cell apoptosis and caspase 3 activity by flow cytometry and with a Caspase 3 Activity Kit, respectively. Results: Specific down-regulation of GCF2 expression caused cell growth inhibition, and increased apoptosis and caspase 3 activity in HepG2 cells. Conclusions: These primary results suggest that GCF2 may influence cell proliferation and apoptosis in HepG2 cells, and also provides a molecular basis for further investigation into the possible mechanism at proliferation and apoptosis in HCC.

• 대한두경부종양학회지
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• 제33권1호
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• pp.21-29
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• 2017

Methylation of CpG islands in the promoter region of genes acts as a significant mechanism of epigenetic gene silencing in head and neck squamous cell carcinoma (HNSCC). DNA methylation markers are particularly advantageous because DNA methylation is an early event in tumorigenesis, and the epigenetic modification, 5-methylcytosine, is a stable mark. In the present study, we assessed the genome-wide preliminary screening and were to identify novel methylation biomarker candidate in HNSCC. Genome-wide methylation analysis was performed on 10 HNSCC tumors using the Methylated DNA Isolation Assay (MeDIA) CpG island microarray. Validation was done using immunohistochemistry using tissue microarray of 135 independent HNSCC tumors. In addition, in vitro proliferation, migration/invasion assays, RT-PCR and immunoblotting were performed to elucidate molecular regulating mechanisms. Our preliminary validation using CpG microarray data set, immunohisto-chemistry for HNSCC tumor tissues and in vitro functional assays revealed that methylation of the Homeobox B5 (HOXB5) and H6 Family Homeobox 2 (HMX2) could be possible novel methylation biomarkers in HNSCC.

• BMB Reports
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• 제56권10호
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• pp.563-568
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• 2023

DNA methylation regulates gene expression and contributes to tumorigenesis in the early stages of cancer. In colorectal cancer (CRC), CpG island methylator phenotype (CIMP) is recognized as a distinct subset that is associated with specific molecular and clinical features. In this study, we investigated the genome-wide DNA methylation patterns among patients with CRC. The methylation data of 1 unmatched normal, 142 adjacent normal, and 294 tumor samples were analyzed. We identified 40,003 differentially methylated positions with 6,933 (79.8%) hypermethylated and 16,145 (51.6%) hypomethylated probes in the genic region. Hypermethylated probes were predominantly found in promoter-like regions, CpG islands, and N shore sites; hypomethylated probes were enriched in open-sea regions. CRC tumors were categorized into three CIMP subgroups, with 90 (30.6%) in the CIMP-high (CIMP-H), 115 (39.1%) in the CIMP-low (CIMP-L), and 89 (30.3%) in the non-CIMP group. The CIMP-H group was associated with microsatellite instability-high tumors, hypermethylation of MLH1, older age, and right-sided tumors. Our results showed that genome-wide methylation analyses classified patients with CRC into three subgroups according to CIMP levels, with clinical and molecular features consistent with previous data.

• 생명과학회지
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• 제19권7호
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• pp.949-955
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• 2009

점막 상피는 외부 인자를 감지하는 최전선의 인식부위로서 외부스트레스 자극을 하부의 반응 신호로 전달하는 주요 세포이다. 리보솜독성 반응을 유발하는 데옥시니발레놀 (DON) 및 그 관련 곰팡이 독소는 푸자륨 곰팡이 오염에 의한 식중독성 소화기 염증성 질환과의 연관성이 알려 져 있다. 본 연구의 목적은 DON이 상피세포 감지 신호 전달 분자로서 PKR과 EGR-1이 관련 되고 이들이 상피세포에서의 염증성 사이토가인 인터루킨 8의 생성에 관련 된다는 가정 하에서 연구를 수행 하였다. PKR 발현의 세포내 작용 억제는 DON에 의해 유도되는 인터루킨 8의 생성을 감소시켰다. 또한 DON에 의한 IL-8 전사 활성화는 PKR 억제에 의하여 장관 상피세포에서 감소하였다. PKR 저해제의 처리는 EGR-1 promoter 활성, mRNA, 단백질 유도 등을 감소를 유발하였으며 MAP kinase (ERK1/2, p38, JNK)는 변화가 적거나 오히려 PKR 저해제의 전처리에 의하여 항진 되었다. 결론적으로 DON에 의해 자극된 감지신호인 EGR-1은 자체적으로 또는 PKR 신호를 경유하여 인터루킨8의 생산을 항진하는데 주요한 기능을 하였다. 이를 통하여 향후 리보솜 독성 반응과 관련된 소화기 염증유발의 주요한 기전을 제공하고 있다.

• Journal of Plant Biotechnology
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• 제39권3호
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• pp.140-145
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• 2012

고온에서 발현이 유도되도록 한 개화촉진유전자 HSpro-FT를 국립원예특작과학원에서 육성된 스프레이타입 국화 2품종('Pink PangPang'과 'Pink Pride')에 도입하여 획득한 형질전환체가 고온기에 화아가 분화하고 고온단일조건에서 화아가 발달하게 되는 조건에서 재배되었을 때 개화가 촉진되었다. HSpro-FT 유전자는 pCAMBIA2300에 삽입되어 Agrobacterium tumefaciens C58C1을 통하여 국화로 도입되었다. 아그로박테리움과의 접종 후 재분화 배지(MS + 1.0 mg/L BA + 0.5 mg/L IAA + 0.7% plant agar, pH 5.8)에 10 mg/L 과 20 mg/L kanamycin이 첨가된 1, 2차 선발배지에서 재분화된 신초를 선발하였다. PCR분석에 의해 'Pink PangPang'유래 재분화 신초 117개체와 'Pink Pride'유래 5개체로부터 FT 유전자가 도입되었음을 확인하였다. HSpro-FT 유전자 형질전환 26계통중 8계통들이 바형질전환체에 비하여 정식 후 꽃봉오리 맺히기까지의 기간이 1.7~10일 당겨졌고, 24계통들이 비형질전환체에 비하여 꽃봉오리 맺힌 후 꽃잎전개까지의 기간이 1~6일 당겨졌다. 두 품종 유래 형질전환 24계통 모두 조기개화성 이외의 꽃모양이나 꽃 색깔 등 다른 특성은 비형질전환체와 같았다.