Yu-Chyi Hwang | National Taiwan University (original) (raw)
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Papers by Yu-Chyi Hwang
Proceedings of the …, Jan 1, 2006
Nasopharyngeal carcinoma (NPC) is one of the common cancers in Chinese living in South China, Hon... more Nasopharyngeal carcinoma (NPC) is one of the common cancers in Chinese living in South China, Hong Kong, Singapore, and Taiwan. Although Epstein-Barr virus (EBV) has been proposed to be closely associated with NPC, the actual etiological factors for this disease are still ...
American Journal …, Jan 1, 2009
China, Singapore, and Taiwan. At present, its etiological factors are not well defined. To identi... more China, Singapore, and Taiwan. At present, its etiological factors are not well defined. To identify which genetic alterations might be involved in NPC pathogenesis, we identified genes that were differentially expressed in NPC cell lines and normal nasomucosal cells using subtractive hybridization and microarray analysis. Most NPC cell lines and biopsy specimens were found to have higher expression levels of the gene encoding nucleolar and coiled-body phosphoprotein 1 (NOLC1) as compared with normal cells. Severe combined immunodeficiency mice bearing NPC xenografts derived from NOLC1-short hairpin-RNA-transfected animals were found to have 82% lower levels of tumor growth than control mice as well as marked tumor cell apoptosis. Measuring the expression levels of genes related to cell growth, apoptosis, and angiogenesis, we found that the MDM2 gene was down-regulated in the transfectants. Both co-transfection and chromatin immunoprecipitation experiments showed that tumor protein 53-regulated expression of the MDM2 gene requires co-activation of NOLC1. These findings suggest that NOLC1 plays a role in the regulation of tumorigenesis of NPC and demonstrate that both NOLC1 and tumor protein 53 work together synergistically to activate the MDM2 promoter in
Functional & integrative …, Jan 1, 2007
It was proposed that Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma... more It was proposed that Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma (NPC); however, the molecular mechanisms involved in the effect of EBV on NPC host genes have not yet been well defined. For this study, two sets of microarray experiments, NPC (EBV-free) vs normal epithelial cells and EBV + vs EBV j NPC arrays, were analyzed and the datasets were crosscompared to identify any correlation between gene clusters involved in EBV targeting and the NPC host gene expression profiles. Statistical analysis revealed that EBV seems to have a preference for targeting more genes from the differentially expressed group in NPC cells than those from the ubiquitously expressed group. Furthermore, this trend is also reflected in log ratios where the EBV target genes of the differentially expressed group origin showed greater log ratios than genes with an origin from the ubiquitously expressed NPC group. Taken together, the genome-wide comparative scanning of EBV and NPC Funct Integr Genomics (2007) 7:79-93 transcriptomes has successfully demonstrated that EBV infection has an intensifying effect on the signals involved in NPC gene expression both in breadth (the majority of the genes) and in depth (greater log ratios).
Proceedings of the …, Jan 1, 2006
Nasopharyngeal carcinoma (NPC) is one of the common cancers in Chinese living in South China, Hon... more Nasopharyngeal carcinoma (NPC) is one of the common cancers in Chinese living in South China, Hong Kong, Singapore, and Taiwan. Although Epstein-Barr virus (EBV) has been proposed to be closely associated with NPC, the actual etiological factors for this disease are still ...
American Journal …, Jan 1, 2009
China, Singapore, and Taiwan. At present, its etiological factors are not well defined. To identi... more China, Singapore, and Taiwan. At present, its etiological factors are not well defined. To identify which genetic alterations might be involved in NPC pathogenesis, we identified genes that were differentially expressed in NPC cell lines and normal nasomucosal cells using subtractive hybridization and microarray analysis. Most NPC cell lines and biopsy specimens were found to have higher expression levels of the gene encoding nucleolar and coiled-body phosphoprotein 1 (NOLC1) as compared with normal cells. Severe combined immunodeficiency mice bearing NPC xenografts derived from NOLC1-short hairpin-RNA-transfected animals were found to have 82% lower levels of tumor growth than control mice as well as marked tumor cell apoptosis. Measuring the expression levels of genes related to cell growth, apoptosis, and angiogenesis, we found that the MDM2 gene was down-regulated in the transfectants. Both co-transfection and chromatin immunoprecipitation experiments showed that tumor protein 53-regulated expression of the MDM2 gene requires co-activation of NOLC1. These findings suggest that NOLC1 plays a role in the regulation of tumorigenesis of NPC and demonstrate that both NOLC1 and tumor protein 53 work together synergistically to activate the MDM2 promoter in
Functional & integrative …, Jan 1, 2007
It was proposed that Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma... more It was proposed that Epstein-Barr virus (EBV) is closely associated with nasopharyngeal carcinoma (NPC); however, the molecular mechanisms involved in the effect of EBV on NPC host genes have not yet been well defined. For this study, two sets of microarray experiments, NPC (EBV-free) vs normal epithelial cells and EBV + vs EBV j NPC arrays, were analyzed and the datasets were crosscompared to identify any correlation between gene clusters involved in EBV targeting and the NPC host gene expression profiles. Statistical analysis revealed that EBV seems to have a preference for targeting more genes from the differentially expressed group in NPC cells than those from the ubiquitously expressed group. Furthermore, this trend is also reflected in log ratios where the EBV target genes of the differentially expressed group origin showed greater log ratios than genes with an origin from the ubiquitously expressed NPC group. Taken together, the genome-wide comparative scanning of EBV and NPC Funct Integr Genomics (2007) 7:79-93 transcriptomes has successfully demonstrated that EBV infection has an intensifying effect on the signals involved in NPC gene expression both in breadth (the majority of the genes) and in depth (greater log ratios).