• Proceedings of the Korean Society of Applied Pharmacology
• /
• 2001.11a
• /
• pp.108-108
• /
• 2001

Axin2/Conductin/Axil and its ortholog Axin are negative regulators of the Wnt signaling pathway, which promote the phosphorylation and degradation of ${\beta}$-catenin. While Axin is expressed ubiquitously, Axin2 mRNA was seen in a restricted pattern during mouse embryogenesis and organogenesis. Because many sites of Axin2 expression overlapped with those of several Wnt genes, we tested whether Axin2 was induced by Wnt signaling. Endogenous Axin2 mRNA and protein expression could be rapidly induced by activation of the Wnt pathway, and Axin2 reporter constructs, containing a 5.6 kb DNA fragment including the promoter and first intron, were also induced. This genomic region contains eight Tcf/LEF consensus binding sites, five of which are located within longer, highly conserved non-coding sequences. The mutation or deletion of these Tcf/LEF sites greatly diminished induction by ${\beta}$-catenin, and mutation of the Tcf/LEF site T2 abolished protein binding in an electrophoretic mobility-shift assay. These results strongly suggest that Axin2 is a direct target of the Wnt pathway, mediated through Tcf/LEF factors. The 5.6 kb genomic sequence was sufficient to direct the tissue specific expression of d2EGFP in transgenic embryos, consistent with a role for the Tcf/LEF sites and surrounding conserved sequences in the in vivo expression pattern of Axin2. Our results suggest that Axin2 participates in a negative feedback loop, which could serve to limit the duration or intensity of a Wnt-initiated signal.

• Korean Journal of Head & Neck Oncology
• /
• v.14 no.1
• /
• pp.20-26
• /
• 1998

Objectives: Deletion in the short arm of chromosome 3 is common in many human cancers, including sporadic and hereditary renal carcinomas, small cell lung carcinomas, non-small cell lung carcinomas, and carcinomas of the ovary, breast, and cervix. A high frequency of chromosomal aberrations in head and neck cancers involving chromosome 3p has also been reported. These findings suggest that multiple tumor suppressor genes may be present on the short arm of chromosome 3. Materials and Methods: To investigate the possibility of chromosome 3p deletions in the Korean head and neck cancer patients, we applied a polymerase chain reaction(PCR)-based Restriction Fragment Length Polymorphism analysis to the DNA samples of matched normal mucosa and head and neck squamous cell carcinomas from 19 patients. Results: In the 19 normal samples heterozygosity at the polymorphic loci varied: 6 at the D3F15S2 locus(on telomeric 3p21), 2 at the D3S32 locus(on centromeric 3p21), and 4 at the THRB locus(on centromeric 3p24). In 12 matched carcinoma specimens, LOH(loss of heterozygosity) was observed at D3F15S2 in 1 of 6(17%), D3S32 in 1 of 2(50%), and at THRB in 2 of 4 cases(50%). Conclusion: The frequency of chromosome 3p deletion in the Korean head and neck carcinomas appear as other country did.

• Korean Journal of Clinical Laboratory Science
• /
• v.45 no.1
• /
• pp.32-36
• /
• 2013

The thyroid is the organ that has the greatest risk of malignant tumors among the endocrine tumors. The papillary carcinoma occupies 80% of the entire thyroid tumors. Immunohistochemical staining of galectin-3 has usually been used in differentiating papillary carcinoma and follicular carcinoma. The p53 gene of the cell cycle is a tumor suppressor gene acting in on the control points. The cyclin D1 genes in the cell cycle, involved in the implementation of G1 and S phase, plays an important role in the progression of thyroid tumors. This research compares and analyzes correlation between papillary carcinoma, follicular carcinoma, p53, cyclin D1 and galectin-3 gene expression patterns. In a total of 30 cases from papillary carcinoma, 21 cases from p53 (70%), 27 cases in galectin-3 (90%), and 26 cases in cyclin D1 (86.7%) showed positive rate. The galectin-3 staining investigated, showed a significant difference between a papillary carcinoma and a follicular carcinoma. Follicular carcinoma from 15 cases, p53 in 13 cases (86.7%), galectin-3 in 5 cases (33.3%) and cyclin D1 in 12 cases (80%) showed a positive rate. The cyclin D1 in follicular carcinoma and staining between the p53 that had correlation was also investigated. In this study, as the examples of the expression of the 27 cases of galectin-3 (90%) in papillary carcinoma and 5 cases in follicular carcinoma (33.3%) indicate, it was concluded that there is a difference in the expression on both carcinoma. In addition, cyclin D1 and p53 has a positive rate in follicular carcinoma, when cyclin D1 in 12 cases (80%), there was a significant correlation that was investigated. Distinguishing between papillary carcinoma and follicular carcinoma can be identified by the expression of galectin-3. It is considered to get results that are more accurate in follicular carcinoma diagnosis depending on whether the cyclin D1 and p53 is expressed or not.

• Asian Pacific Journal of Cancer Prevention
• /
• v.13 no.5
• /
• pp.1833-1836
• /
• 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.

• Journal of Microbiology and Biotechnology
• /
• v.19 no.11
• /
• pp.1482-1489
• /
• 2009

In this study, we investigated the anti-proliferative effect of polysaccharides from Salicornia herbacea on HT-29 human colon cancer cells. Crude polysaccharides from S. herbacea (CS) were prepared by extraction with hot steam water, and fine polysaccharides from S. herbacea (PS) were obtained through further size exclusion chromatography. The anti-proliferative effect of CS and PS were measured using the MTS assay, apoptosis analysis, cell cycle analysis, and RT-PCR. HT-29 cells were treated with CS or PS at different dosages (0.5, 1, 2, 4 mg $ml^{-1}$) for 24 or 48 h. CS and PS inhibited proliferation and stimulated apoptosis of cells in a dose-dependent manner. Flow cytometric analysis after Annexin V-FITC and PI staining revealed that treatment with CS or PS increased total apoptotic death of cells to 24.99% or 91.59%, respectively, in comparison with the control (13.51 %). PS increased early apoptotic death substantially - up to 12 times more than the control. Treatment with CS or PS resulted in a concentration-dependent increase of the G2/M cell population of the cell cycle as determined by flow cytometry. G2/M arrest was induced significantly with the highest concentration (4 mg $ml^{-1}$) of PS. RT-PCR was performed to study the correlation between G2/M arrest and transcription of cell cycle control genes. The anti-proliferative activity of CS and PS was accompanied by inhibition of cyclin B1, and Cdc 2 mRNA. Moreover, both CS and PS induced expression of the p53 tumor suppressor gene and the Cdk inhibitor p21. These results suggest that polysaccharides from S. herbacea have anti-cancer activity in human colon cancer cells.

• Molecules and Cells
• /
• v.26 no.1
• /
• pp.5-11
• /
• 2008

Stalled DNA replication forks activate specific DNA repair mechanism called post-replication repair (PRR) pathways that simply bypass DNA damage. The bypassing of DNA damage by PRR prevents prolonged stalling of DNA replication that could result in double strand breaks (DSBs). Proliferating cell nuclear antigen (PCNA) functions to initiate and choose different bypassing pathways of PRR. In yeast, DNA replication forks stalled by DNA damage induces monoubiquitination of PCNA at K164, which is catalyzed by Rad6/Rad18 complex. PCNA monoubiquitination triggers the replacement of replicative polymerase with special translesion synthesis (TLS) polymerases that are able to replicate past DNA lesions. The PCNA interaction motif and/or the ubiquitin binding motif in most TLS polymerases seem to be important for the regulation of TLS. The TLS pathway is usually error-prone because TLS polymerases have low fidelity and no proofreading activity. PCNA can also be further polyubiquitinated by Ubc13/ Mms2/Rad5 complex, which adds an ubiquitin chain onto monoubiquitinated K164 of PCNA. PCNA polyubiquitination directs a different PRR pathway known as error-free damage avoidance, which uses the newly synthesized sister chromatid as a template to bypass DNA damage presumably through template switching mechanism. Mammalian homologues of all of the yeast PRR proteins have been identified, thus PRR is well conserved throughout evolution. Mutations of some PRR genes are associated with a higher risk for cancers in mice and human patients, strongly supporting the importance of PRR as a tumor suppressor pathway.

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

• Journal of the Korean Chemical Society
• /
• v.50 no.2
• /
• pp.116-122
• /
• 2006

In this study we extracted DNA from 100 tissues of breast cancer patients and 103 normals. Then we confirmed single-nucleotide polymorphism(SNP) using PCR-DHPLC(polymerase chain reaction-denaturing high performance liquid chromatogrphy).Also, we studied SNP of samples using several columns to identify relation between packing materials of column and resolution.As a result, we identified 4 C/A, C/G genotypes(4%) in exon 5 and 37 T del genotypes(37%) in exon 8 among 100 breast cancer tissues and 2 in exon 5, 9 in exon 8 among 103 normal samples.In resolution test, we confirmed that PS-DVB(poly styrene-divinylbenzen) column is more efficient than C18 column.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.38 no.5
• /
• pp.644-648
• /
• 2009

Antiproliferative effects of soy milk fermented with Bacillus subtilis from chungkukjang was studied in AGS human gastric adenocarcinoma cells. The fermented soy milk by B. subtilis (B. subtilis-F-SM) exhibited 82% growth inhibitory effect at 2 mg/mL concentration, while non-fermented soy milk (Non-F-SM) showed 68%. B. subtilis-F-SM treated AGS cells induced more apoptotic bodies than the Non-F-SM treated cells. In mRNA expressions, B. subtilis-F-SM showed decreased expression of anti-apoptotic bcl-2 and increased expression of pro-apoptotic bax. The expressions of tumor suppressor genes of p53 and p21 were also increased. These results suggest that fermented soy milk by B. subtilis exhibited higher antiproliferative activities compared with non-fermented soy milk.

• Toxicological Research
• /
• v.25 no.1
• /
• pp.35-40
• /
• 2009

TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) and related halogenated aromatic hydrocarbons elicit a diverse spectrum of biochemical and toxic responses in laboratory animals and mammalian cells in culture. Toxicity and carcinogenicity of TCDD is well established but the molecular mechanism is still poorly understood. Here, we found the noble responsive genes to TCDD using the differential display analysis. Treatment of HepG2 cells with TCDD showed a significantly different mRNA expression pattern from the untreated cells in differential display analysis. The differentially displayed bands were isolated and used as probes in dot blot and Northern blot analyses. Of thirty-five isolated differentially displayed bands, only two bands were confirmed as positive in dot blot and Northern blot analyses. The nucleotides sequences of these clones were analyzed and the search of Genebank database revealed that one clone is highly homologous with RanBP2 (Ras-related nuclear protein binding protein2; 92%) and the other is an unknown gene. RanBP2 is a nucleoporin with SUMO E3 ligase activity that functions in both nucleocytoplasmic transport and mitosis and its role as a novel tumor suppressor has been recently proposed. Thus, these results may suggest the clue elucidating the toxic mechanism of TCDD through RanBP2.