• The Korean Journal of Physiology and Pharmacology
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• v.23 no.6
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• pp.475-482
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• 2019

Glioma is the most common brain tumor with a dismal prognosis. While temozolomide (TMZ) based chemotherapy significantly improves survival in glioma patients, resistance against this compound commonly leads to glioma treatment failure. Overexpression of long-noncoding RNA (LncRNA) FoxD2 adjacent opposite strand RNA 1 (FoxD2-AS1) was identified to promote glioma development, but the role in TMZ resistance remains unclear. In this paper, we found that FoxD2-AS1 was overexpressed in recurrent glioma, high FoxD2-AS1 expression was significantly correlated with poor patient outcome. Methylation of $O^6$-methylguanine-DNA methyltransferase (MGMT) is significantly less frequent in high FoxD2-AS1 expression patients. Knockdown of FoxD2-AS1 decreased the proliferation, metastatic ability of glioma cells and promote the sensitivity to TMZ in glioma cells. Furthermore, knockdown of FoxD2-AS1 induced hypermethylation of the promoter region of MGMT. Our data suggested that FoxD2-AS1 is a clinical relevance LncRNA and mediates TMZ resistance by regulating the methylation status of the MGMT promoter region.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.6
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• pp.453-459
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• 2010

Introduction: Ameloblastic carcinoma is a rare malignant lesion, and may arise from either carcinoma ex-ameloblastoma or de novo carcinoma. Aberrant promoter hypermethylation of the tumor-associated genes leading to their inactivation is a common event in many cancer types. The p16/CDKN2/INK4A gene and p16 5 protein are involved directly in regulating the cell cycles. Cadherins are cell adhesion molecules that modulate the epithelial phenotype and regulate tumor invasion. The aim of this study was to evaluate the roles of p16 and E-cadherin methylation and loss of p16 and E-cadherin expression in the malignant transformation of an ameloblastoma. Materials and Methods: Eight cases of ameloblastoma, including 4 benign ameloblastomas without recurrence, 2 benign ameloblastomas with recurrence and 2 carcinoma ex-ameloblastomas, were examined. The promoter hypermethylation profile of the p16 and E-cadherin genes was studied using methylation-specific polymerase chain reaction (MSP) and immunohistochemical staining for p16 and E-cadherin expression. Results: 1) Aberrant CpG island methylation of the p16 gene was detected in 3 of the 4 benign ameloblastomas without recurrence and 1 of the 2 benign ameloblastomas with recurrence. 2) Aberrant CpG island methylation of the E-cadherin gene was found in 1 of the 4 benign ameloblastomas without recurrence. 3) A loss of p16 expression was noted in 1 of 4 benign ameloblastomas without recurrence and 1 of 2 carcinoma ex-ameloblastomas. 4) A loss of E-cadherin expression was noted in 2 of the 4 benign ameloblastomas without recurrence, 1 of the 2 benign ameloblastomas with recurrence and 2 of the 2 carcinoma ex-ameloblastomas. 5) A loss of p16 expression was observed in 1 of the 4 cases showing aberrant methylation of the p16 gene. 6) A loss of E-cadherin expression was observed in 3 benign ameloblastoma case showing aberrant methylation of the E-cadherin gene. Conclusion: These results suggest that loss of E-cadherin expression related to the other genetic pathway (not methylation) might be an adjuvant indicator predicting the malignant transformation of an ameloblastoma. However, the number of samples in this study was too small and the relationship between the treatment methods and clinical course were not defined. Therefore, further study will be needed.

• BMB Reports
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• v.44 no.8
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• pp.523-528
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• 2011

To identify novel genes that are regulated by promoter methylation, a combinational approach involving in silico mining followed by molecular assay was performed. From the expression microarray data registered in the European bioinformatics institute (EBI), genes showing downregulation in breast cancer cells were initially screened and then selected by e-Northern analysis using the Unigene database. A series of these in silico methods identified CAMK2B and ARFGEF1 as candidates, and the two genes were revealed to be hypermethylated in breast cancer cell lines and hypomethylated in normal breast cell lines. Additionally, cancer cell lines showed downregulated expression of these genes. Furthermore, treatment of the cancer cell lines with a demethylation agent, 5-Aza-2'-deoxycytidine, recovered expression of CAMK2B and ARFGEF1, implying that hypermethyaltion silenced gene activity in cancer cells. Taken together, promoter methylations of CAMK2B and ARFGEF1 are novel epigenetic markers identified in breast cancer cell lines and can be utilized for the application to clinical cancer tissues.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.8957-8961
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• 2014

Background: Promoter hypermethylation leads to altered gene functions and may result in malignant cellular transformation. Thus, identification of biomarkers for hypermethylated genes could be useful for diagnosis, prognosis, and therapeutic treatment of oral squamous cell carcinoma (OSCC). Objectives: To screen hypermethylated genes with a microarray approach and to validate selected hypermethylated genes with the methylation-specific polymerase chain reaction (MSPCR). Materials and Methods: Genome-wide analysis of normal oral mucosa and OSCC tissues was conducted using the Illumina methylation microarray. The specified differential genes were selected and hypermethylation status was further verified with an independent cohort sample of OSCC samples. Candidate genes were screened using microarray assay and run by MSPCR analysis. Results: TP73, PIK3R5, and CELSR3 demonstrated high percentages of differential hypermethylation status. Conclusions: Our microarray screening and MSPCR approaches revealed that the signature candidates of differentially hypermethylated genes may possibly become potential biomarkers which would be useful for diagnostic, prognostic and therapeutic targets of OSCC in the near future.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.3
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• pp.1197-1200
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• 2015

Breast cancer metastasis is a major cause of cancer-related death in women. However, markers for diagnosis of breast cancer metastasis are rare. Here, we reported that TET1, a tumor suppressor gene, was downregulated and hypermethylated in highly metastatic breast cancer cell lines. Moreover, silencing of TET1 in breast cancer cells increased the migration and spreading of breast cancer cells. In breast cancer clinical samples, TET1 expression was reduced in LN metastases compared with primary tissues. Besides, the methylation level of the TET1 promoter was increased significantly in LN metastases. Taken together, these findings indicate that promoter hypermethylation may contribute to the downregulation of TET1 and could be used as a promising marker for diagnosis in patients with breast cancer metastasis.

• Molecules and Cells
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• v.42 no.7
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• pp.530-545
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• 2019

Tumor cells can vary epigenetically during ionizing irradiation (IR) treatment. These epigenetic variegations can influence IR response and shape tumor aggressiveness. However, epigenetic disturbance of histones after IR, implicating in IR responsiveness, has been elusive. Here, we investigate whether altered histone modification after IR can influence radiation responsiveness. The oncogenic CXCL12 mRNA and protein were more highly expressed in residual cancer cells from a hepatoma heterotopic murine tumor microenvironment and coculture of human hepatoma Huh7 and normal IMR90 cells after radiation. H3K4 methylation was also enriched and H3K9 methylation was decreased at its promoter region. Accordingly, invasiveness and the subpopulation of aggressive $CD133^+/CD24^-$ cells increased after IR. Histone demethylase inhibitor IOX1 attenuated CXCL12 expression and the malignant subpopulation, suggesting that responses to IR can be partially mediated via histone modifications. Taken together, radiation-induced histone alterations at the CXCL12 promoter in hepatoma cells are linked to CXCL12 upregulation and increased aggressiveness in the tumor microenvironment.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2004.05a
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• pp.63-63
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• 2004

• International Journal of Oral Biology
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• v.31 no.2
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• pp.27-32
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• 2006

Expression of invasion/metastasis suppressor, E-cadherin, is reduced in many types of human carcinomas. Although somatic and germline mutations in the CDH1, which encodes the human E-cadherin, have frequently been reported in cases with diffuse gastric and lobular breast cancers, irreversible genetic inactivations are rare in other human carcinomas. Recently, it has been well documented that some genes in human cancers may be inactivated by altered CpG methylation. Herein, we determined the expression and methylation status of E-cadherin in oral squamous cell carcinoma(SCC) by immunohistochemistry and methylation-specific PCR. The expression of E-cadherin was significantly higher in the well-differentiated oral SCCs than the moderately or poorly differentiated ones. None of eight tested benign epithelial hyperplasias showed aberrant methylation, whereas five of 12 oral squamous cell carcinomas showed aberrant methylation. When we compared E-cadherin expression with methylation status, oral SCCs with normal methylation showed a higher expression of E-cadherin than those with methylation. These findings suggest that aberrant CpG methylation of CDH1 promoter region is closely associated with transcriptional inactivation and might be involved in tumor progression of the oral mucosa.

• Tuberculosis and Respiratory Diseases
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• v.60 no.2
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• pp.160-170
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• 2006

Background : The aberrant promoter hypermethylation of p16INK4a, as a tumor suppressor gene, is contributory factor to non-small cell lung cancer(NSCLC). However, its potential diagnostic impact of lung cancer is unclear. This study measured the level of $p16^{INK4a}$ promoter hypermethylation in the sputum and blood, and compared this with the level measured in the tissue obtained from NSCLC and pulmonary inflammation. Methods : Of the patients who visited the Our Lady of Mercy Hospital in Incheon, Korea for an evaluation of a lung mass and underwent blood, sputum, and tissue tests, 23patients (18 NSCLC, 5 pulmonary inflammation) were enrolled in this study. DNA was extracted from each sample and the level of p16INK4amethylation was determined using methylation-specific polymerase chain reaction. Results : $p16^{INK4a}$ methylation of the blood was observed in 88.9% (16 of 18) and 20.0% (1 of 5) of NSCLC and from pulmonary inflammation samples, respectively (P=0.008). Methylation of the sputum was observed in 83.3% (10 of 12) 80.0% (4 of 5) of NSCLC and pulmonary inflammation samples, respectively (P=1.00). Among the 8 NSCLC tissue samples, methylation changes were detected in 75.0% of samples (6 cases). Four out of seven tissue samples (57.1%) showed concordance, being methylated in both the blood and sputum. Conclusions : There was a higher level of $p16^{INK4a}$ methylation of the blood from NSCLC patients than from pulmonary inflammation. The tissue showed a high concordance with the blood in the NSCLC samples. These findings suggest that $p16^{INK4a}$ promoter hypermethylation of the blood can used to discriminate between NSCLC and pulmonary inflammation.

• Journal of Chest Surgery
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• v.53 no.1
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• pp.22-27
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• 2020

Background: Previous studies have shown that lung cancer stem cells express CD133 and that certain cancer stem cells express cancer germline antigens (CGAs). The transcriptional regulation of CD133 is complicated and poorly understood. We investigated CD133 and CGA expression in a non-small cell lung cancer cell line. Methods: The expression levels of CD133 and CGAs (MAGE-6, GAGE, SSX, and TRAG-3) were measured in an NCI-H292 lung cancer cell line. The methylation status of the CD133 gene promoter region was analyzed. The expression levels and promoter methylation statuses of CD133 and CGAs were confirmed by treatment with the demethylating agent 5-aza-2'-deoxycytidine (ADC). Results: After treatment with ADC, CD133 expression was no longer detected. MAGE-6 and TRAG-3 were detected before ADC treatment, while GAGE and SSX were not detected. ADC treatment upregulated MAGE-6 and TRAG-3 expression, while GAGE expression was still undetected after treatment, and only weak SSX expression was observed. GAGE expression was not correlated with expression of CD133, while the levels of expression of MAGE-6, TRAG-3, and SSX were inversely correlated with CD133 expression. Conclusion: These results showed that CD133 expression can be regulated by methylation. Thus, the demethylation of the CD133 promoter may compromise the treatment of lung cancer by inactivating cancer stem cells and/or activating CGAs.