• Journal of Life Science
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• v.15 no.3 s.70
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• pp.323-331
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• 2005

The objective of the present study was to investigate the effect of $\beta-lapachone$, a quinone obtained from the bark of the lapacho tree (Tabebuia avellanedae) in South America, on the cell growth of human hepatoma (HepG2) and bladder (T24) carcinoma cells. Exposure of cancer cells to $\beta-lapachone$ resulted in growth inhibition, morphological changes and apoptosis in a concentration-dependent manner, which could be proved by MTT assay and flow cytometry analysis. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analyses revealed that $\beta-lapachone$ did not affect the levels of tumor suppressor p53 and cyclin-dependent kinase (Cdk) inhibitor p21 (WAFl/CIPl) expression. However, the transcriptional factor Sp-l and proliferating cell nuclear antigen (PCNA) protein levels were significantly down-regulated by $\beta-lapachone$ in both cell lines. Moreover, $\beta-lapachone$ treatment caused a dose-dependent inhibition of the expression of telomere regulatory gene products such as human telomere reverse transcriptase (hTERT) and telomerase-associated protein-l (TEP-l). Taken together, these findings suggest that $\beta-lapachone$-induced inhibition of human hepatoma and bladder carcinoma cell proliferation is associated with the induction of apoptotic cell death via modulation of several major growth regulatory gene products, and provide important new insights into the additional mechanisms of the anti-cancer activity of $\beta-lapachone$.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.996-1001
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• 2007

To investigate whether sulindac, sulindac sulfone, and sulindac sulfide could affect cancer cell viabilities, human colorectal HCTl16 cells were treated with 10 ${\mu}M$ of each NSAID. Among treated NSAms, sulindac sulfide dramatically decreased the cell viabilities detected by MTS and the cytotoxic effect showed dose-dependent manner. To understand the molecular mechanism of cell death in response to sulindac sulfide treatment, we performed oligo DNA microarray analysis. We found that 23 genes were up-regulated more than 2 folds, whereas 33 genes were down-regulated more than 2 folds by treatment of 10 ${\mu}M$ sulindac sulfide. Among the up-regulated genes, we selected 3 genes (NAG-1, DDIT3, PCK2) and performed RT-PCR and quantitative real-time PCR to cofirm microarray data. The results of RT-PCR and real-time PCR were highly accorded with those of microarray experiment. As NAG-1 is well-known gene as tumor suppressor, we detected changes of NAG-1 expression by 10 ${\mu}M$ of sulindac, sulindac sulfone, and sulindac sulfide. The results of RT-PCR and quantitacve real-time PCR indicated that sulindac sulfide was the strongest inducer of NAG-1 among treated NSAIDS. This result implies that induction of NAG-1 by sulindac sulfide plays important role in cell death of colorectal cancer. Overall, we speculate that these results may be helpful in understanding the molecular mechanism of the cancer chemoprevention by sulindac sulfide in human colorectal cancer.

• Journal of Microbiology and Biotechnology
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• v.33 no.9
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• pp.1206-1212
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• 2023

The Wnt/β-catenin pathway plays essential roles in regulating various cellular behaviors, including proliferation, survival, and differentiation [1-3]. The intracellular β-catenin level, which is regulated by a proteasomal degradation pathway, is critical to Wnt/β-catenin pathway control [4]. Normally, casein kinase 1 (CK1) and glycogen synthase kinase-3β (GSK-3β), which form a complex with the scaffolding protein Axin and the tumor suppressor protein adenomatous polyposis coli (APC), phosphorylate β-catenin at Ser45, Thr41, Ser37, and Ser33 [5, 6]. Phosphorylated β-catenin is ubiquitinated by the β-transducin repeat-containing protein (β-TrCP), an F-box E3 ubiquitin ligase complex, and ubiquitinated β-catenin is degraded via a proteasome pathway [7, 8]. Colorectal cancer is a significant cause of cancer-related deaths worldwide. Abnormal up-regulation of the Wnt/β-catenin pathway is a major pathological event in intestinal epithelial cells during human colorectal cancer oncogenesis [9]. Genetic mutations in the APC gene are observed in familial adenomatous polyposis coli (FAP) and sporadic colorectal cancers [10]. In addition, mutations in the N-terminal phosphorylation motif of the β-catenin gene were found in patients with colorectal cancer [11]. These mutations cause β-catenin to accumulate in the nucleus, where it forms complexes with transcription factors of the T-cell factor/lymphocyte enhancer factor (TCF/LEF) family to stimulate the expression of β-catenin responsive genes, such as c-Myc and cyclin D1, which leads to colorectal tumorigenesis [12-14]. Therefore, downregulating β-catenin response transcription (CRT) is a potential strategy for preventing and treating colorectal cancer. Plant cytokinins are N⁶-substituted purine derivatives; they promote cell division in plants and regulate developmental pathways. Natural cytokinins are classified as isoprenoid (isopentenyladenine, zeatin, and dihydrozeatin), aromatic (benzyladenine, topolin, and methoxytopolin), or furfural (kinetin and kinetin riboside), depending on their structure [15, 16]. Kinetin riboside was identified in coconut water and is a naturally produced cytokinin that induces apoptosis and exhibits antiproliferative activity in several human cancer cell lines [17]. However, little attention has been paid to kinetin riboside's mode of action. In this study, we show that kinetin riboside exerts its cytotoxic activity against colon cancer cells by suppressing the Wnt/β-catenin pathway and promoting intracellular β-catenin degradation.

• Tuberculosis and Respiratory Diseases
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• v.57 no.3
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• pp.265-272
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• 2004

Background : RASSF1A, which is one of tumor suppressor genes, is frequently inactivated by hypermethylation of the promoter region in a variety of human cancers, including lung cancer. This study was performed to investigate the association between RASSF1A methylation and the clinicopathological factors in patients with squamous cell carcinoma of the lung. Methods : Eighty-one samples from the patients with squamous cell carcinoma of lung were examined. The promoter methyation of RASSF1A was analyzed by methylation specific PCR and sequencing. Statistical analysis was made to examine the association between RASSF1A methylation and the clinicopathological parameters. Results : RASSF1A methylation was observed in 37.0 % (30 of 81) of the patients with squamous cell carcinoma of the lung. RASSF1A methylation was found to be associated with cellular differentiation(p=0.0097) and the overall survival(p=0.0635). However, there was no association between RASSF1A methylation and the other clinicopathological parameters, such as the pathological TNM stage, the recurrence rate, lymph node invasion and the amount of cigarettes smoked. Conclusion : RASSF1A methylation might be associated with a poor prognosis in patients with squamous carcinoma of the lung. A larger scale study is needed.

• Korean Journal of Microbiology
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• v.42 no.4
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• pp.319-325
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• 2006

[ $\beta$ ]-Glucans (AG) were prepared from Agaricus blazei cultured in the medium fortified with the roots of Pueraria spp. by repeated extraction with hot water, gel filtration chromatography and DEAE ion exchange chromatography. Oligosaccharides (AO) were derived from the hydrolysis of AG by an endo-$\beta$-(1$\rightarrow$6)-glucanase from Bacillus megaterium. The anti-HT-29 human colon cancer activity of AG or AO was investigated using MTT assay, apoptosis assay, cell cycle analysis, and cDNA microairay. AG and AO both inhibited proliferation and growth of HT-29 cells, and stimulated apoptosis of the cells in a dose-dependent manner. In cell cycle analysis, treating HT-29 cells with AG or AO resulted in the increase of cells in the G0 (sub-G1) and G1 phase. Especially, AO was more effective in inducing G0/G1 cell cycle arrest than AG. To screen the genes involved in the increase of apoptosis, the gene expression profile of the HT-29 cells treated with AO was examined by cDNA microarray. While several genes involved in cell cycle progression (CCND2 and CDK2) were down-regulated, many genes involved in apoptosis (TNFSF9, TNFRSF9, FADD, CASP8, BAD, CRADD, CASP9 etc), cell cycle inhibitor (CDKN2A), immune response (IL6, IL18, IL6R etc), and tumor suppressor (CEACAM1, TP53BP2, IRF1, and PHB) were up-regulated. These results suggest that AO could inhibit the proliferation and growth of HT-29 cells by G0/G1 cell cycle arrest and induction of apoptosis.

• Tuberculosis and Respiratory Diseases
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• v.44 no.3
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• pp.534-546
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• 1997

Background : The p53 and retinoblastoma(Rb) tumor suppressor genes are associated with the pathogenesis of several types of human cancer. Substantial proportion of the primary lung cancers or cell lines have been reported to have the p53 and/or the Rb gene mutations. But, so far there is no report on the analysis of the Rb gene polymorphism as one of the genetic susceptibility marker. This study was undertaken to establish the gene frequencies of the polymorphic genotypes of the p53 and Rb genes in Koreans to evaluate the possible involvement of these genotypes as a risk factor of lung cancer. Methods : In this study 145 controls without previous and present tumor history and 128 lung cancer patients were subjected to analysis. The two intragenic polymorphisms of the p53 gene(exon 4/ AccII, intron 6/MspI) and one intron 17/XbaI polymorphism of the Rb gene were analysed by the method of polymersae chain reaction- restriction fragment length polymorphisms(PCR-RFLPs). The genotype of the intron 3/16 bp repeat polymorphism of p53 was determined by PCR and direct gel electrophoresis. Results : There were no significant differences in the genotype distributions of the p53 gene between lung cancer patients and controls. But heterozygotes(Arg/Pro) of the exon 4/AccII polymorphisms were slightly over-represented than controls, especially in the Kreyberg type I cancer, which was known to be associated with smoking. The intron 3/16 bp duplication and the intron 6/MspI polymorphisms were in complete linkage disequilibrium. About 95% of the individuals were homozygotes of the common alleles both in the 16 duplication and MspI polymorphisms, and no differences were deteced in the genotype distributions between lung cancer patients and controls. Overall genotype distributions of the Rb gene polymorphisms between lung cancer patients and controls were not significantly different However, the genotype distributions in the Kreyberg type I cancer were significantly different from those of controls(p = 0.0297) or adenocarcinomas(p = 0.0008). It was noticeable that 73.4% of the patients with adenocarcinomas were heterozygotes(r1/r2) whereas 39.2% of the Kreyberg type I cancer were heterozygous at this polymorphisms. In the lung cancer patients, significant differences were also noted between the high dose smokers and low dose smokers including non-smokers(p = 0.0258). The relative risk to Kreyberg type I cancer was significantly reduced in the individuals with the genotype of r1/r2(odds ratio = 0.46, 95% C.I. = 0.25-0.86, p = 0.0124). The combined genotype distribution of the exon 4 AccII of the p53 and the intron 17 Rb gene polymorphisms in Kreyberg type I cancers were significantly different from dose of controls or adenocarcinomas. The highest odds ratio were observed in the individuals with the genotypes of Arg/Pro and r2/r2(odds ratio = 1.97,95% C.I. = 0.84-4.59) and lowest one was in the patients with Arg/Arg, r1/r2 genotype(odds ratio = 0.54, 95% C.I. = 0.25-1.14). Conclusion : The p53 and the Rb gene polymorphisms modulate the risk of smoking induced lung cancer development in Koeans. However, the exact mechanism of risk modulation by these polymorphism remains to be determined. For more discrete clarification of associations between specific genotypes and lung cancer risk, the evaluations of these polymorphisms in other ethnics and more number of patients will be needed.

• Journal of Life Science
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• v.18 no.8
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• pp.1132-1139
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• 2008

A CpG island is a short stretch of DNA in which the frequency of the CG dinucleotide is higher than other regions. CpG islands are present in the promoters and exonic regions of approximately $30{\sim}60$% of mammalian genes so they are useful markers for genes in organisms containing 5-methylcytosine in their genomes. Recent evidence supports the notion that the hypermethylation of CpG island, by silencing tumor suppressor genes, plays a major causal role in cancer, which has been described in almost every tumor types. In this respect, CpG island search by computational methods is very helpful for cancer research and computational promoter and gene predictions. I therefore developed a window program (called CpGi) on the basis of CpG island criteria defined by D. Takai and P. A. Jones. The program 'CpGi' was implemented in Visual C++ 6.0 and can determine the locations of CpG islands using diverse parameters (%GC, Obs (CpG)/Exp (CpG), window size, step size, gap value, # of CpG, length) specified by user. The analysis result of CpGi provides a graphical map of CpG islands and G+C% plot, where more detailed information on CpG island can be obtained through pop-up window. Two human contigs, i.e. AP00524 (from chromosome 22) and NT_029490.3 (from chromosome 21), were used to compare the performance of CpGi and two other public programs for the accuracy of search results. The two other programs used in the performance comparison are Emboss-CpGPlot and CpG Island Searcher that are web-based public CpG island search programs. The comparison result showed that CpGi is on a level with or outperforms Emboss-CpGPlot and CpG Island Searcher. Having a simple and easy-to-use user interface, CpGi would be a very useful tool for genome analysis and CpG island research. To obtain a copy of CpGi for academic use only, contact corresponding author.

• Journal of Life Science
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• v.25 no.8
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• pp.947-952
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• 2015

Prostate apoptosis response-4 (Par-4) was originally identified in androgen-independent prostate cancer cells undergoing apoptosis. Par-4 is ubiquitously expressed in normal cells and tissues, but it is downregulated in several types of cancers. Par-4 is a 38 kDa tumor suppressor protein encoded by the PARW gene. Par-4 promotes apoptosis in a variety of cancerous cells, but not in normal cells. In this review, we focused on the structure, expression and function of Par-4 in apoptotic signaling pathway. Functional domains of Par-4 include two nuclear localization sequences (NLS), a leucine zipper (LZ) domain, a nuclear export sequence (NES) and selective for apoptosis in cancer cell (SAC) domain. Many studies have underlined the importance of Par-4 in preventing cancer development. The activity of Par-4 is differently regulated by localization of intracellular and extracellular Par-4. Intracellular Par-4 inhibits Akt- and NF-κB-mediated cell survival pathways and downregulates Bcl-2 expression. Extracellular Par-4 activates the extrinsic apoptotic pathway by binding to cell surface receptor GRP78, a stress response protein that is in the endoplasmic reticulum (ER). Endogenous Par-4 sensitizes cancer cells to various apoptotic stimuli, while exogenous Par-4 enhances SAC domain-dependent apoptosis in cancer cells, but not normal cells. Therefore, Par-4 is an attractive target for cancer therapy.

• Journal of the korean academy of Pediatric Dentistry
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• v.38 no.2
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• pp.187-193
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• 2011

Neurofibromatosis is known as an autosomal dominant disorder caused by a mutation of a tumor suppressor gene on the long arm of chromosome 17 that affects the bone, nervous system, soft tissue, skin, and endocrine system. The most characteristic finding, which is helpful for clinical diagnosis as well, is the neurofibroma. Likewise brown macules called Cafe-au-lait spots with color of caffee latte, and Lisch nodules found around iris are useful to diagnose the disease. As known, the possibility of the neurofibromatosis occurred in oral cavity is relatively rare, and in most of cases it is related to soft tissue changes with single or multiple neurofibromatosis. The purpose of this report is to present characteristic dental findings which were found in a 4-year-old male and his father, both diagnosed as neurofibromatosis at Chonbuk National University Hospital before visiting our department, pediatric dentistry.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2699-2705
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• 2014

This study was to undertaken to investigate the impacts of AhR, CYP1A1, GSTM1 genetic polymorphisms on the R273G mutation in exon 8 of the tumor suppressor p53 gene (TP53) among polycyclic aromatic hydrocarbons (PAHs) exposed to coke-oven workers. One hundred thirteen workers exposed to PAH and 82 control workers were recruited. We genotyped for polymorphisms in the AhR, CYP1A1, GSTM1, and TP53 R273G mutation in blood by PCR methods, and determined the levels of 1-hydroxypyrene as PAH exposure marker in urine using the high pressure liquid chromatography assay. We found that the distribution of alcohol users and the urinary excretion of 1-OHP in the exposed workers were significantly higher than that of the control workers (p=0.004, p<0.001, respectively). Significant differences were observed in the p53 genotype distributions of smoking subjects (p=0.01, 95%CI: 1.23-6.01) and PAH exposure (p=0.008, 95%CI: 1.24-4.48), respectively. Further, significant differences were observed in the p53 exon 8 mutations for the genetic polymorphisms of Lys/Arg for AhR (p=0.02, 95%CI: 0.70-15.86), Val/Val for CYP1A1 (p=0.04, 95%CI: 0.98-19.09) and null for GSTM1 (p=0.02, 95%CI: 1.19-6.26), respectively. Our findings indicated that polymorphisms of PAH metabolic genes, such as AhR, CYP1A1, GSTM1 polymorphisms may interact with p53 genetic variants and may contribute to PAH related cancers.