• BMB Reports
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• v.44 no.4
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• pp.267-272
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• 2011

ZAS3 is a large zinc finger transcription repressor that binds the ${\kappa}B$-motif via two signature domains of ZASN and ZASC. A loss-of-function study showed that lack of ZAS3 protein induced accelerated cell proliferation and tumorigenesis. Conversely, gain-of-function studies showed that ZAS3 repressed $NF{\kappa}B$-activated transcription by competing with $NF{\kappa}B$ for the ${\kappa}B$-motif. Based on these observations, we hypothesize that ZAS3 promotes apoptosis by interrupting anti-apoptotic activity of $NF{\kappa}B$. Here, we present evidence that upon $TNF{\alpha}$ stimulation, ZAS3 inhibits $NF{\kappa}B$-mediated cell survival and promotes caspase-mediated apoptosis. The inhibitory effect of ZAS3 on $NF{\kappa}B$ activity is mediated by neither direct association with $NF{\kappa}B$ nor disrupting nuclear localization of $NF{\kappa}B$. Instead, ZAS3 repressed the expression of two key anti-apoptotic genes of $NF{\kappa}B$, TRAF1 and TRAF2, thereby sensitizing cells to $TNF{\alpha}$-induced cell death. Taken together, our data suggest that ZAS3 is a tumor suppressor gene and therefore serves as a novel therapeutic target for developing anti-cancer drugs.

• Journal of Ginseng Research
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• v.45 no.6
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• pp.754-762
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• 2021

Background: Ginsenoside Rh2, a major saponin derivative in ginseng extract, is recognized for its anti-cancer activities. Compared to coding genes, studies on long noncoding RNAs (lncRNAs) and microRNAs (miRNAs) that are regulated by Rh2 in cancer cells, especially on competitive endogenous RNA (ceRNA) are sparse. Methods: LncRNAs whose promoter DNA methylation level was significantly altered by Rh2 were screened from methylation array data. The effect of STXBP5-AS1, miR-4425, and RNF217 on the proliferation and apoptosis of MCF-7 breast cancer cells was monitored in the presence of Rh2 after deregulating the corresponding gene. The ceRNA relationship between STXBP5-AS1 and miR-4425 was examined by measuring the luciferase activity of a recombinant luciferase/STXBP5-AS1 plasmid construct in the presence of mimic miR-4425. Results: Inhibition of STXBP5-AS1 decreased apoptosis but stimulated growth of the MCF-7 cells, suggesting tumor-suppressive activity of the lncRNA. MiR-4425 was identified to have a binding site on STXBP5-AS1 and proven to be downregulated by STXBP5-AS1 as well as by Rh2. In contrast to STXBP5-AS1, miR-4425 showed pro-proliferation activity by inducing a decrease in apoptosis but increased growth of the MCF-7 cells. MiR-4425 decreased luciferase activity from the luciferase/STXBP5-AS1 construct by 26%. Screening the target genes of miR-4425 and Rh2 revealed that Rh2, STXBP5-AS1, and miR-4425 consistently regulated tumor suppressor RNF217 at both the RNA and protein level. Conclusion: LncRNA STXBP5-AS1 is upregulated by Rh2 via promoter hypomethylation and acts as a ceRNA, sponging the oncogenic miR-4425. Therefore, Rh2 controls the STXBP5-AS1/miR-4425/RNF217 axis to suppress breast cancer cell growth.

• Proceedings of the Korean Society for Bioinformatics Conference
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• 2001.10a
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• pp.61-86
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• 2001

All cancers are caused by abnormalities in DNA sequence. Throughout life, the DNA in human cells is exposed to mutagens and suffers mistakes in replication, resulting in progressive, subtle changes in the DNA sequence in each cell. Since the development of conventional and molecular cytogenetic methods to the analysis of chromosomal aberrations in cancers, more than 1,800 recurring chromosomal breakpoints have been identified. These breakpoints and regions of nonrandom copy number changes typically point to the location of genes involved in cancer initiation and progression. With the introduction of molecular cytogenetic methodologies based on fluorescence in situ hybridization (FISH), namely, comparative genomic hybridization (CGH) and multicolor FISH (m-FISH) in carcinomas become susceptible to analysis. Conventional CGH has been widely applied for the detection of genomic imbalances in tumor cells, and used normal metaphase chromosomes as targets for the mapping of copy number changes. However, this limits the mapping of such imbalances to the resolution limit of metaphase chromosomes (usually 10 to 20 Mb). Efforts to increase this resolution have led to the "new"concept of genomic DNA chip (1 to 2 Mb), whereby the chromosomal target is replaced with cloned DNA immobilized on such as glass slides. The resulting resolution then depends on the size of the immobilized DNA fragments. We have completed the first draft of its Korean Genome Project. The project proceeded by end sequencing inserts from a library of 96,768 bacterial artificial chromosomes (BACs) containing genomic DNA fragments from Korean ethnicity. The sequenced BAC ends were then compared to the Human Genome Project′s publicly available sequence database and aligned according to known cancer gene sequences. These BAC clones were biotinylated by nick translation, hybridized to cytogenetic preparations of metaphase cells, and detected with fluorescein-conjugated avidin. Only locations of unique or low-copy Portions of the clone are identified, because high-copy interspersed repetitive sequences in the probe were suppressed by the addition of unlabelled Cotl DNA. Banding patterns were produced using DAPI. By this means, every BAC fragment has been matched to its appropriate chromosomal location. We have placed 86 (156 BAC clones) cytogenetically defined landmarks to help with the characterization of known cancer genes. Microarray techniques would be applied in CGH by replacement of metaphase chromosome to arrayed BAC confirming in oncogene and tumor suppressor gene: and an array BAC clones from the collection is used to perform a genome-wide scan for segmental aneuploidy by array-CGH. Therefore, the genomic DNA chip (arrayed BAC) will be undoubtedly provide accurate diagnosis of deletions, duplication, insertions and rearrangements of genomic material related to various human phenotypes, including neoplasias. And our tumor markers based on genetic abnormalities of cancer would be identified and contribute to the screening of the stage of cancers and/or hereditary diseases

• Journal of Ginseng Research
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• v.41 no.3
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• pp.386-391
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• 2017

Background: Korean Red Ginseng (KRG) is an ethnopharmacological plant that is traditionally used to improve the body's immune functions and ameliorate the symptoms of various diseases. However, the antitumorigenic effects of KRG and its underlying molecular and cellular mechanisms are not fully understood in terms of its individual components. In this study, in vitro and in vivo antitumorigenic activities of KRG were explored in water extract (WE), saponin fraction (SF), and nonsaponin fraction (NSF). Methods: In vitro antitumorigenic activities of WE, SF, and NSF of KRG were investigated in the C6 glioma cell line using cytotoxicity, migration, and proliferation assays. The underlying molecular mechanisms of KRG fractions were determined by examining the signaling cascades of apoptotic cell death by semiquantitative reverse transcriptase polymerase chain reaction and Western blot analysis. The in vivo antitumorigenic activities of WE, SF, and NSF were investigated in a xenograft mouse model. Results: SF induced apoptotic death of C6 glioma cells and suppressed migration and proliferation of C6 glioma cells, whereas WE and NSF neither induced apoptosis nor suppressed migration of C6 glioma cells. SF downregulated the expression of the anti-apoptotic gene B-cell lymphoma-2 (Bcl-2) and upregulated the expression of the pro-apoptotic gene Bcl-2-associated X protein (BAX) in C6 glioma cells but had no effect on the expression of the p53 tumor-suppressor gene. Moreover, SF treatment resulted in activation of caspase-3 as evidenced by increased levels of cleaved caspase-3. Finally, WE, SF, and NSF exhibited in vivo antitumorigenic activities in the xenograft mouse model by suppressing the growth of grafted CT-26 carcinoma cells without decreasing the animal body weight. Conclusion: These results suggest that WE, SF, and NSF of KRG are able to suppress tumor growth via different molecular and cellular mechanisms, including induction of apoptosis and activation of immune cells.

• Molecules and Cells
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• v.24 no.3
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• pp.364-371
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• 2007

The tumor suppressor gene Ras association domain family 1A (RASSF1A) is highly methylated in a wide range of human sporadic tumors. The current study investigated the hypermethylation of RASSF1A, the expression of RASSF1A protein, and the correlation between these and the clinicopathological features of gallbladder (GB) cancer in Korean patients. Formalin-fixed, paraffin-embedded tumors and non-neoplastic GB tissues (22 carcinomas, 8 adenomas, 26 normal epithelia) were collected from patients who had undergone surgical resection. The methylation status of two regions of the RASSF1A CpG island was determined by methylation-specific PCR (MSP), and the expression of RASSF1A protein was examined by immunohistochemistry using tissue microarrays. The K-RAS mutation was analyzed by direct sequencing. Methylation of the RASSF1A promoter (region 1) was detected in 22.7% (5/22) of carcinomas, 12.5% (1/8) of adenomas, and 0% (0/26) of normal gallbladder epithelia (P = 0.025). Methylation of the first exon (region 2) was found in 36.4% (8/22) of carcinomas, 25.0% (2/8) of adenomas, and 8.0% (2/26) of normal gallbladder epithelia (P = 0.038). K-RAS mutations were present in 4.5% (1/22) of carcinomas and 25% (2/8) of adenomas. RASSF1A methylaton was not associated with clinicopathological factors or K-ras mutation. Reduction or loss of RASSF1A expression was observed in most methylated adenocarcinomas. Three RASSF1A-expressing human biliary tract cancer cell lines examined contained unmethylated promoters and exons 1. These results suggest that downregulation of RASSF1A expression by DNA hypermethylation may be involved in GB carcinogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.347-350
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• 2012

TP53 is the mostly commonly mutated gene in many cancers and the P53 tumor suppressor protein is involved in multiple cellular processes, including transcription, DNA repair, genomic stability, senescence, cell cycle control and apoptosis. A common single nucleotide polymorphism located within the proline rich region of TP53 gene at codon 72 in exon 4 encodes either proline or arginine. TP53 Arg 72 is more active than TP53 Pro 72 in inducing apoptosis. The aim of this study was to understand the association of the 72 codon polymorphism with acute leukemia development and prognosis. A total of 288 acute leukemia cases comprising 147 acute lymphocytic leukemia (ALL) and 141 acute myeloid leukemia (AML), as well as 245 controls were recruited for analysis of the TP53 72 polymorphism using PCR-RFLP method. Significant association of homozygous arginine genotype with AML was observed (${\chi}^2$- 133.53; df-2, p < 0.001. When data were analyzed with respect to clinical variables, elevation in mean WBC, blast %, LDH levels and slight reduction in DFS in ALL cases with the arginine genotype was observed. In contrast, AML patients with Pro/Pro had elevated WBC, Blast%, LDH levels with slightly reduced DFS. Our study indicates that Arg/Arg genotype might confer increased risk to development of acute myeloid leukemia.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.2
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• pp.511-516
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• 2012

Background: We investigated the association between polymorphisms in the $p53$ tumor suppressor gene and breast cancer risk in women especially in the Southern part of India. Methods: Genotyping was performed for 50 breast cancer women and 50 controls to determine the status of $p53$ exon 4 codon 72 polymorphism and exon 7 codon 249 mutation and their possible role in breast cancer risk. Results: Frequency of Arg/Arg at codon 72 was 18% in controls and 28% in patients, Arg/Pro frequency was 56% and 66%, Pro/Pro genotype was 8% in controls and 8% in patients. No significance was observed for breast cancer risk with either Arg/Arg or Pro/Pro genotype in codon 72 polymorphism. Similarly, mutation analysis of exon 7 codon 249 revealed that 72% of breast cancer patients have mutation, which is not statistically significant. However, there is a strong association between increase in exon 7 codon 249 mutation and exposure to pollution. Conclusion: The results suggested that there is no risk for exon 4 with Arg/Arg or Pro/Pro polymorphisms in the $p53$ gene and there is no strong correlation between breast cancer patients and mutation in exon 7 codon 249 in South Indian women.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4827-4834
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• 2012

Tumor suppressor genes have received much attention for their roles in the development of human malignancies. Gelsolin has been found to be down-regulated in several types of human cancers, including leukemias. It is, however, expressed in macrophages, which are the final differentiation derivatives for the monocytic myeloid lineage, implicating this protein in the differentiation process of such cells. In order to investigate the role of gelsolin in leukaemic cell differentiation, stable clones over-expressing ectopic gelsolin, and a control clone were established from U937 leukaemia cells. Unlike the control cells, both gelsolin-overexpressing clones displayed retarded growth, improved monocytic morphology, increased NADPH and NSE activities, and enhanced surface expression of the ${\beta}$-integrin receptor, CD11b, when compared with the parental U937 cells. Interestingly, RT-PCR and western blot analysis also revealed that gelsolin enhanced p21CIP1 mRNA and protein expression in the overexpressing clones. Moreover, transient transfection with siRNA silencing P21CIP1, but not the control siRNA, resulted in a reduction in monocytic differentiation, accompanied by an increase in proliferation. In conclusion, our work demonstrates that gelsolin, by itself, is capable of inducing monocytic differentiation in U937 leukaemia cells, most probably through p21CIP1 activation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.6
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• pp.3773-3778
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• 2013

Increased oxidative stress and changes in DNA methylation are frequently detected in bladder cancer patients. We previously demonstrated a relationship between increased oxidative stress and hypomethylation of the transposable long-interspersed nuclear element-1 (LINE-1). Promoter hypermethylation of a tumor suppressor gene, runt-related transcription factor 3 (RUNX3), may also be associated with bladder cancer genesis. In this study, we investigated changes of DNA methylation in LINE-1 and RUNX3 promoter in a bladder cancer cell (UM-UC-3) under oxidative stress conditions, stimulated by challenge with $H_2O_2$ for 72 h. Cells were pretreated with an antioxidant, tocopheryl acetate for 1 h to attenuate oxidative stress. Methylation levels of LINE-1 and RUNX3 promoter were measured by combined bisulfite restriction analysis PCR and methylation-specific PCR, respectively. Levels of LINE-1 methylation were significantly decreased in $H_2O_2$-treated cells, and reestablished after pretreated with tocopheryl acetate. Methylation of RUNX3 promoter was significantly increased in cells exposed to $H_2O_2$. In tocopheryl acetate pretreated cells, it was markedly decreased. In conclusion, hypomethylation of LINE-1 and hypermethylation of RUNX3 promoter in bladder cancer cell line was experimentally induced by reactive oxygen species (ROS). The present findings support the hypothesis that oxidative stress promotes urothelial cell carcinogenesis through modulation of DNA methylation. Our data also imply that mechanistic pathways of ROS-induced alteration of DNA methylation in a repetitive DNA element and a gene promoter might differ.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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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.