• Communications for Statistical Applications and Methods
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• v.29 no.5
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• pp.591-601
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• 2022

In gene set analysis with microarray expression data, a group of genes such as a gene regulatory pathway and a signaling pathway is often tested if there exists either differentially expressed (DE) or differentially co-expressed (DC) genes between two biological conditions. Recently, a statistical test based on covariance estimation have been proposed in order to identify DC genes. In particular, covariance regularization by hard thresholding indeed improved the power of the test when the proportion of DC genes within a biological pathway is relatively small. In this article, we compare covariance thresholding methods using four different regularization penalties such as lasso, hard, smoothly clipped absolute deviation (SCAD), and minimax concave plus (MCP) penalties. In our extensive simulation studies, we found that both SCAD and MCP thresholding methods can outperform the hard thresholding method when the proportion of DC genes is extremely small and the number of genes in a biological pathway is much greater than a sample size. We also applied four thresholding methods to 3 different microarray gene expression data sets related with mutant p53 transcriptional activity, and epithelium and stroma breast cancer to compare genetic pathways identified by each method.

• Journal of Pharmacopuncture
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• v.8 no.1
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• pp.31-40
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• 2005

Objectives : It has long been known about the osteogenic effect of CTF-HAS on bone tissues. However, it has not been determined the effect of CTF-HAS on cancer cells. The purpose of this study is to screen the CTF-HAS mediated differentially expressed genes in cancer cells such as SNU484 gastric cancer cell lines. Oligonucleotide microarray approach were employed to screen the differential expression genes. Methods : CTF-HAS was prepared by boiling and stored at $-70^{\circ}C$ until use. Cells were treated with various concentrations of CTF-HAS(0.1, 0.5, 1.5, 10, 20mg/ml) for 24 h. Cytotoxicity was tested by MTT assay. To screen the differentially expressed genes in cancer cells, cells were treated with 1.5mg/ml of CTF-HAS. For oligonucleotide microarry assay, total RNA was used for gene expression analysis using oligonucleotide genechip (Human genome U133 Plus 2.0., Affimatrix Co.). Results : It has no cytotoxic effects on HepG2 cells in all concentration (0.1, 0.5, 1.5, 10,20mg/ml). More than twofold up-regulated genes were 5 genes. The number of more than twofold down-regulated genes was 10. Discussion : This study showed the screening of CTF-HAS mediated differentially regulated genes using combined approaches of oligonucleotide microarray. The screened genes will be used for the better understanding in therapeutic effect of CTF-HAS on cancer field.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.8
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• pp.3997-4000
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• 2012

MicroRNAs (miRNAs) play roles in the clinic, both as diagnostic and therapeutic tools. The identification of relevant microRNAs is critically required for ovarian cancer because of the prevalence of late diagnosis and poor treatment options currently. To identify miRNAs involved in the development or progression of ovarian cancer, we analyzed gene expression profiles downloaded from Gene Expression Omnibus. Comparison of expression patterns between carcinomas and the corresponding normal ovarian tissues enabled us to identify 508 genes that were commonly up-regulated and 1331 genes that were down-regulated in the cancer specimens. Function annotation of these genes showed that most of the up-regulated genes were related to cell cycling, and most of the down-regulated genes were associated with the immune response. When these differentially expressed genes were mapped to MiRTarBase, we obtained a total of 18 key miRNAs which may play important regulatory roles in ovarian cancer. Investigation of these genes and microRNAs should help to disclose the molecular mechanisms of ovarian carcinogenesis and facilitate development of new approaches to therapeutic intervention.

• Journal of Acupuncture Research
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• v.23 no.3
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• pp.177-190
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• 2006

Objectives : It has long been known about the anticancer effect of GRR-HAS, however, it has not been systemically determined the differentially regulated genes by GRR-HAS in cancer cells. The purpose of this study is to screen the GRR-HAS mediated differentially expressed genes in cancer cells such as HepG2 hepatoma cell lines. Oligonucleotide microarray and proteomic approaches were employed to screen the differential expression genes. Methods : GRR~HAS was prepared by boiling and stored at $-70^{\circ}C$ until use. Cells were treated with various concentrations of GRR-HAS (0.1, 0.5, 1.5, 10, $20mg/m{\ell}$) for 24 h. Cell toxicity was tested by MTT assay. To screen the differentially expressed genes in cancer cells, cells were treated with $1.5mg/m{\ell}$ of GRR-HAS. For oligonucleotide microarray assay, total RNA was used for gene expression analysis using oligonucleotide genechip (Human genome Ul33 Plus 2.0., Affimatrix Co.). For proteomic analysis, total protein was analyzed by 2D gel electrophoresis and Q-TOF mass spectrometer. Results : It has no cytotoxic effects on both HepG2 cells in all concentrations(0.1, 0.5, 1.5, 10,$20mg/m{\ell}$). In oligonucleotide microarray assay, the number of more than twofold differentially regulated known genes was 320 with 6 up-regulated and 314 down-regulated genes in HepG2 cells. In proteomic analysis, three spots were identified by 2D-gel electrophoresis and Q-TOF analysis. One down -regulated protein was protein disulfide isomerase and up-regulated proteins were fatty acid binding protein 1 and 14-3-3 gan1lTIa protein by $1.5mg/m{\ell}$ of CRR-HAS. Discussion : This study showed the comprehensive gene expression analysis using oligonucleotide microarray for the screening of GRR-HAS mediated differentially regulated genes. These results will provide a better application of GRR-HAS in cancer field and drug target development.

• Genomics & Informatics
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• v.18 no.3
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• pp.29.1-29.11
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• 2020

Maize seed pigmentation is one of the important issue to develop maize seed breeding. The differently gene expression was characterized and compared for three inbred lines, such as the pigment accumulated seed (CM22) and non-pigmented seed (CM5 and CM19) at 10 days after pollination. We obtained a total of 63,870, 82,496, and 54,555 contigs by de novo assembly to identify gene expression in the CM22, CM5, and CM19, respectably. In differentially expressed gene analysis, it was revealed that 7,044 genes were differentially expressed by at least two-fold, with 4,067 upregulated in colored maize inbred lines and 2,977 upregulated in colorless maize inbred lines. Of them,18 genes were included to the anthocyanin biosynthesis pathways, while 15 genes were upregulated in both CM22/5 and CM22/19. Additionally, 37 genes were detected in the metabolic pathway concern to the seed pigmentation by BINs analysis using MAPMAN software. Finally, these differently expressed genes may aid in the research on seed pigmentation in maize breeding programs.

• Plant Breeding and Biotechnology
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• v.6 no.4
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• pp.354-362
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• 2018

Maize has high food and industrial value, whereas has difficulties in research because of their complex and huge size genome. Nested association mapping (NAM) was constructed to better understand maize genetics. However, most studies were conducted using the reference genome B73, and only a few studies were conducted on tropical maize. Ki3, one of the founder lines of the NAM population, is a tropical maize. We analyzed the genetic characteristics of Ki3 by using RNA sequencing and bioinformatics tools for various genetic studies. As results, a total of 30,526 genes were expressed, and expression profile were constructed. A total of 1,558 genes were differentially expressed in response to drought stress, and 513 contigs of them come from de novo assemblies. In addition, high-density polymorphisms including 464,930 single nucleotide polymorphisms (SNPs), 21,872 multiple nucleotide polymorphisms (MNPs) and 93,313 insertions and deletions (InDels) were found compared to reference genome. Among them, 15.0 % of polymorphisms (87,838) were passed non-synonymous test which could alter amino acid sequences. The variants have 66,550 SNPs, 5,853 MNPs, and 14,801 InDels, also proportion of homozygous type was higher than heterozygous. These variants were found in a total of 15,643 genes. Of these genes, 637 genes were found as differentially expressed genes (DEGs) under drought stress. Our results provide a genome-wide analysis of differentially expressed genes and information of variants on expressed genes of tropical maize under drought stress. Further characterization of these changes in genetic regulation and genetic traits will be of great value for improvement of maize genetics.

• Toxicological Research
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• v.25 no.2
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• pp.85-92
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• 2009

4,4'-Methylenedianiline (MDA) is an aromatic amine that is widely used in the industrial synthetic process. Genotoxic MDA forms DNA adducts in the liver and is known to induce liver damage in human and rats. To elucidate the molecular mechanisms associated with MDA-induced hepatotoxicity, we have identified genes differentially expressed by microarray approach. BALB/c male mice were treated once daily with MDA (20 mg/kg) up to 7 days via intraperitoneal injection (i.p.) and hepatic damages were revealed by histopathological observation and elevation of serum marker enzymes such as AST, ALT, ALP, cholesterol, DBIL, and TBIL. Microarray analysis showed that 952 genes were differentially expressed in the liver of MDA-treated mice and their biological functions and canonical pathways were further analyzed using Ingenuity Pathways Analysis (IPA). Toxicological functional analysis showed that genes related to hepatotoxicity such hyperplasia/hyperproliferation (Timp1), necrosis/cell death (Cd14, Mt1f, Timp1, and Pmaip1), hemorrhaging (Mt1f), cholestasis (Akr1c3, Hpx, and Slc10a2), and inflammation (Cd14 and Hpx) were differentially expressed in MDA-treated group. This gene expression profiling should be useful for elucidating the genetic events associated with aromatic amine-induced hepatotoxicity and for discovering the potential biomarkers for hepatotoxicity.

• Genomics & Informatics
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• v.12 no.4
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• pp.171-180
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• 2014

Aberrant DNA methylation, as an epigenetic marker of cancer, influences tumor development and progression. We downloaded publicly available DNA methylation and gene expression datasets of matched cancer and normal pairs from the Cancer Genome Atlas Data Portal and performed a systematic computational analysis. This study has three aims to screen genes that show hypermethylation and downregulated patterns in colorectal cancers, to identify differentially methylated regions in one of these genes, SFRP1, and to test whether the SFRP genes affect survival or not. Our results show that 31 hypermethylated genes had a negative correlation with gene expression. Among them, SFRP1 had a differentially methylated pattern at each methylation site. We also show that SFRP1 may be a potential biomarker for colorectal cancer survival.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10797-10801
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• 2015

Background: To explore the molecular mechanisms of metastatic osteosarcoma (OS) by using the microarray expression profiles of metastatic and non-metastatic OS samples. Materials and Methods: The gene expression profile GSE37552 was downloaded from Gene Expression Omnibus database, including 2 human metastatic OS cell line models and 2 two non-metastatic OS cell line models. The differentially expressed genes (DEGs) were identified by Multtest package in R language. In addition, functional enrichment analysis of the DEGs was performed by WebGestalt, and the protein-protein interaction (PPI) networks were constructed by Hitpredict, then the signal pathways of the genes involved in the networks were performed by Kyoto Encyclopaedia of Genes and Genomes (KEGG) automatic annotation server (KAAS). Results: A total of 237 genes were classified as DEGs in metastatic OS. The most significant up- and down-regulated genes were A2M (alpha-2-macroglobulin) and BCAN (brevican). The DEGs were significantly related to the response to hormone stimulus, and the PPI network of A2M contained IL1B (interleukin), LRP1 (low-density lipoprotein receptor-related protein 1) and PDGF (platelet-derived growth factor). Furthermore, the MAPK signaling pathway and focal adhesion were significantly enriched. Conclusions: A2M and its interactive proteins, such as IL1B, LRP1 and PDGF may be candidate target molecules to monitor, diagnose and treat metastatic OS. The response to hormone stimulus, MAPK signaling pathway and focal adhesion may play important roles in metastatic OS.

• Korean Journal of Acupuncture
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• v.23 no.2
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• pp.125-136
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• 2006

Objectives: It has long been known about the osteogenic effect of CPC-HAS(cervi parvum cornu herbal-acupuncture solution) on bone tissues. However, it has not been determined the effect of CPC-HAS on cancer cells. The purpose of this study is to screen the CPC-HAS mediated differentially expressed genes..in cancer cells such as SNU484 gastric cancer cell lines. Oligonucleotide microarray approache was employed to screen the differential expression genes. Methods: CPC-HAS was prepared by boiling and stored at $-70^{\circ}C$ until use. Cells were treated with various concentrations of CPC-HAS (0.1, 0.5, 1.5, 10, 20 mg/ml) for 24 h. Cell toxicity was tested by MTT assay. To screen the differentially expressed genes in cancer cells, cells were treated with 1.5 mg/ml of CPC-HAS. For oligonucleotide microarray assay, total RNA was used for gene expression analysis using oligonucleotide Genechip(Human genome U133 Plus 2.0., Affimatrix Co.). Results: It has no cytotoxic effects on SNU484 cell in all concentrations(0.l, 0.5, 1.5, 10, 20 mg/ml). In oligonucleotide microarray assay, in SNU484 cells, the number of more than twofold up-regulated genes was 5 while, the number of more than twofold down-regulated genes was 10. Conclusions: This study showed the screening of CPC-HAS mediated differentially regulated genes using combined approaches of oligonucleotide microarray. The screened genes will be used for the better understanding of the therapeutic effects of CPC-HAS on cancer fields.