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Sung HY, Han J, Chae YJ, Ju W, Kang JL, Park AK, Ahn JH. Identification of a novel PARP4 gene promoter CpG locus associated with cisplatin chemoresistance. BMB Rep 2023; 56:347-352. [PMID: 37013346 PMCID: PMC10315564 DOI: 10.5483/bmbrep.2022-0202] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/28/2022] [Accepted: 04/01/2023] [Indexed: 10/11/2023] Open
Abstract
The protein family of poly (ADP-ribose) polymerases (PARPs) is comprised of multifunctional nuclear enzymes. Several PARP inhibitors have been developed as new anticancer drugs to combat resistance to chemotherapy. Herein, we characterized PARP4 mRNA expression profiles in cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. PARP4 mRNA expression was significantly upregulated in cisplatin-resistant ovarian cancer cell lines, and this upregulation was associated with the hypomethylation of specific cytosine-phosphate-guanine (CpG) sites (cg18582260 and cg17117459) on its promoter. Reduced PARP4 expression was restored by treating cisplatin-sensitive cell lines with a demethylation agent, implicating the epigenetic regulation of PARP4 expression by promoter methylation. Depletion of PARP4 expression in cisplatin-resistant cell lines reduced cisplatin chemoresistance and promoted cisplatin-induced DNA fragmentation. The differential mRNA expression and DNA methylation status at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) according to cisplatin responses, was further validated in primary ovarian tumor tissues. The results showed significantly increased PARP4 mRNA expressions and decreased DNA methylation levels at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) in cisplatin-resistant patients. Additionally, the DNA methylation status at cg18582260 CpG sites in ovarian tumor tissues showed fairly clear discrimination between cisplatin-resistant patients and cisplatin-sensitive patients, with high accuracy (area under the curve = 0.86, P = 0.003845). Our findings suggest that the DNA methylation status of PARP4 at the specific promoter site (cg18582260) may be a useful diagnostic biomarker for predicting the response to cisplatin in ovarian cancer patients. [BMB Reports 2023; 56(6): 347-352].
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 07804, Korea
| | - Jihye Han
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 07804, Korea
| | - Yun Ju Chae
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 07804, Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul 07804, Korea
| | - Jihee Lee Kang
- Department of Physiology, College of Medicine, Ewha Womans University, Seoul 07804, Korea
- Inflammation-Cancer Microenvironment Research Center, College of Medicine, Ewha Womans University, Seoul 07804, Korea
| | - Ae Kyung Park
- Department of Pharmacy, School of Pharmacy, Jeonbuk National University, Jeonju 54896, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 07804, Korea
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Sung HY, Lee S, Han M, An WJ, Ryu H, Kang E, Park YS, Lee SE, Ahn C, Oh KH, Park SK, Ahn JH. Epigenome-wide association study of diabetic chronic kidney disease progression in the Korean population: the KNOW-CKD study. Sci Rep 2023; 13:8175. [PMID: 37210443 DOI: 10.1038/s41598-023-35485-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Accepted: 05/18/2023] [Indexed: 05/22/2023] Open
Abstract
Since the etiology of diabetic chronic kidney disease (CKD) is multifactorial, studies on DNA methylation for kidney function deterioration have rarely been performed despite the need for an epigenetic approach. Therefore, this study aimed to identify epigenetic markers associated with CKD progression based on the decline in the estimated glomerular filtration rate in diabetic CKD in Korea. An epigenome-wide association study was performed using whole blood samples from 180 CKD recruited from the KNOW-CKD cohort. Pyrosequencing was also performed on 133 CKD participants as an external replication analysis. Functional analyses, including the analysis of disease-gene networks, reactome pathways, and protein-protein interaction networks, were conducted to identify the biological mechanisms of CpG sites. A phenome-wide association study was performed to determine the associations between CpG sites and other phenotypes. Two epigenetic markers, cg10297223 on AGTR1 and cg02990553 on KRT28 indicated a potential association with diabetic CKD progression. Based on the functional analyses, other phenotypes (blood pressure and cardiac arrhythmia for AGTR1) and biological pathways (keratinization and cornified envelope for KRT28) related to CKD were also identified. This study suggests a potential association between the cg10297223 and cg02990553 and the progression of diabetic CKD in Koreans. Nevertheless, further validation is needed through additional studies.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, Ewha Womans University College of Medicine, 25 Magokdong‑ro 2‑gil, Gangseo‑gu, Seoul, 07804, South Korea
| | - Sangjun Lee
- Department of Preventive Medicine, Seoul National University College of Medicine, 103, Daehak-ro, Jongro-gu, Seoul, 03080, South Korea
- Cancer Research Institute, Seoul National University, Seoul, South Korea
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, South Korea
| | - Miyeun Han
- Department of Internal Medicine, National Medical Center, Seoul, South Korea
| | - Woo Ju An
- Department of Preventive Medicine, Seoul National University College of Medicine, 103, Daehak-ro, Jongro-gu, Seoul, 03080, South Korea
- Cancer Research Institute, Seoul National University, Seoul, South Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul, South Korea
| | - Hyunjin Ryu
- Department of Internal Medicine, Seoul National University Hospital, 103, Daehak-ro, Jongro-gu, Seoul, 03080, Republic of Korea
| | - Eunjeong Kang
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Ewha Womans University College of Medicine, Seoul, South Korea
| | - Yong Seek Park
- Department of Microbiology, School of Medicine, Kyung Hee University, Seoul, South Korea
| | - Seung Eun Lee
- Department of Microbiology, School of Medicine, Kyung Hee University, Seoul, South Korea
| | - Curie Ahn
- Department of Internal Medicine, National Medical Center, Seoul, South Korea
- Department of Internal Medicine, Seoul National University Hospital, 103, Daehak-ro, Jongro-gu, Seoul, 03080, Republic of Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University Hospital, 103, Daehak-ro, Jongro-gu, Seoul, 03080, Republic of Korea.
| | - Sue K Park
- Department of Preventive Medicine, Seoul National University College of Medicine, 103, Daehak-ro, Jongro-gu, Seoul, 03080, South Korea.
- Cancer Research Institute, Seoul National University, Seoul, South Korea.
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul, South Korea.
| | - Jung-Hyuck Ahn
- Department of Biochemistry, Ewha Womans University College of Medicine, 25 Magokdong‑ro 2‑gil, Gangseo‑gu, Seoul, 07804, South Korea.
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Han M, Moon S, Lee S, Kim K, An WJ, Ryu H, Kang E, Ahn JH, Sung HY, Park YS, Lee SE, Lee SH, Jeong KH, Ahn C, Kelly TN, Hsu JY, Feldman HI, Park SK, Oh KH. Novel Genetic Variants Associated with Chronic Kidney Disease Progression. J Am Soc Nephrol 2023; 34:857-875. [PMID: 36720675 PMCID: PMC10125649 DOI: 10.1681/asn.0000000000000066] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2022] [Accepted: 12/11/2022] [Indexed: 02/02/2023] Open
Abstract
SIGNIFICANCE STATEMENT eGFR slope has been used as a surrogate outcome for progression of CKD. However, genetic markers associated with eGFR slope among patients with CKD were unknown. We aimed to identify genetic susceptibility loci associated with eGFR slope. A two-phase genome-wide association study identified single nucleotide polymorphisms (SNPs) in TPPP and FAT1-LINC02374 , and 22 of them were used to derive polygenic risk scores that mark the decline of eGFR by disrupting binding of nearby transcription factors. This work is the first to identify the impact of TPPP and FAT1-LINC02374 on CKD progression, providing predictive markers for the decline of eGFR in patients with CKD. BACKGROUND The incidence of CKD is associated with genetic factors. However, genetic markers associated with the progression of CKD have not been fully elucidated. METHODS We conducted a genome-wide association study among 1738 patients with CKD, mainly from the KoreaN cohort study for Outcomes in patients With CKD. The outcome was eGFR slope. We performed a replication study for discovered single nucleotide polymorphisms (SNPs) with P <10 -6 in 2498 patients with CKD from the Chronic Renal Insufficiency Cohort study. Several expression quantitative trait loci (eQTL) studies, pathway enrichment analyses, exploration of epigenetic architecture, and predicting disruption of transcription factor (TF) binding sites explored potential biological implications of the loci. We developed and evaluated the effect of polygenic risk scores (PRS) on incident CKD outcomes. RESULTS SNPs in two novel loci, TPPP and FAT1-LINC02374 , were replicated (rs59402340 in TPPP , Pdiscovery =7.11×10 -7 , PCRIC =8.13×10 -4 , Pmeta =7.23×10 -8 ; rs28629773 in FAT1-LINC02374 , Pdiscovery =6.08×10 -7 , PCRIC =4.33×10 -2 , Pmeta =1.87×10 -7 ). The eQTL studies revealed that the replicated SNPs regulated the expression level of nearby genes associated with kidney function. Furthermore, these SNPs were near gene enhancer regions and predicted to disrupt the binding of TFs. PRS based on the independently significant top 22 SNPs were significantly associated with CKD outcomes. CONCLUSIONS This study demonstrates that SNP markers in the TPPP and FAT1-LINC02374 loci could be predictive markers for the decline of eGFR in patients with CKD.
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Affiliation(s)
- Miyeun Han
- Department of Internal Medicine, National Medical Center, Seoul, Korea
| | - Sungji Moon
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
- Interdisciplinary Program in Cancer Biology, Seoul National University College of Medicine, Seoul, Korea
- Genomic Medicine Institute, Seoul National University College of Medicine, Seoul, Korea
| | - Sangjun Lee
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
- Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea
| | - Kyungsik Kim
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
- Department of Biomedical Science, Seoul National University Graduate School, Seoul, Korea
| | - Woo Ju An
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Hyunjin Ryu
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Eunjeong Kang
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Ewha Womans University College of Medicine, Seoul, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul, Korea
| | - Hye Youn Sung
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul, Korea
| | - Yong Seek Park
- Department of Microbiology, School of Medicine, Kyung Hee University, Seoul, Korea
| | - Seung Eun Lee
- Department of Microbiology, School of Medicine, Kyung Hee University, Seoul, Korea
| | - Sang-Ho Lee
- Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea
| | - Kyung Hwan Jeong
- Department of Internal Medicine, Kyung Hee University School of Medicine, Seoul, Korea
| | - Curie Ahn
- Department of Internal Medicine, National Medical Center, Seoul, Korea
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
| | - Tanika N. Kelly
- Department of Epidemiology, Tulane University, New Orleans, Louisiana
| | - Jesse Y. Hsu
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Harold I. Feldman
- Department of Biostatistics, Epidemiology and Informatics, University of Pennsylvania Perelman School of Medicine, Philadelphia, Pennsylvania
| | - Sue K. Park
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul, Korea
- Cancer Research Institute, Seoul National University, Seoul, Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul, Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University Hospital, Seoul, Korea
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Sung HY, Han J, Chae YJ, Ju W, Lee Kang J, Park AK, Ahn JH. Identification of a novel PARP4 gene promoter CpG locus associated with cisplatin chemoresistance. BMB Rep 2023:5820. [PMID: 37013346] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Abstract
The protein family of poly (ADP-ribose) polymerases (PARPs) is comprised of multifunctional nuclear enzymes. Several PARP inhibitors have been developed as new anticancer drugs to combat resistance to chemotherapy. Herein, we characterized PARP4 mRNA expression profiles in cisplatin-sensitive and cisplatin-resistant ovarian cancer cell lines. PARP4 mRNA expression was significantly upregulated in cisplatin-resistant ovarian cancer cell lines, and this upregulation was associated with hypomethylation of specific cytosine-phosphate-guanine (CpG) sites (cg18582260 and cg17117459) on its promoter. Reduced PARP4 expression was restored by treating cisplatin-sensitive cell lines with a demethylation agent, implicating epigenetic regulation of PARP4 expression by promoter methylation. Depletion of PARP4 expression in cisplatin-resistant cell lines reduced cisplatin chemoresistance and promoted cisplatin-induced DNA fragmentation. The differential mRNA expression and DNA methylation status at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) according to cisplatin responses, were further validated in primary ovarian tumor tissues. The results showed significantly increased PARP4 mRNA expressions and decreased DNA methylation levels at specific PARP4 promoter CpG sites (cg18582260 and cg17117459) in cisplatin-resistant patients. Additionally, the DNA methylation status at cg18582260 CpG sites in ovarian tumor tissues showed fairly clear discrimination between cisplatin-resistant patients and cisplatin-sensitive patients, with high accuracy (area under the curve = 0.86, p = 0.003845). Our findings suggested that the DNA methylation status of PARP4 at the specific promoter site (cg18582260) may be a useful diagnostic biomarker for predicting the response to cisplatin in ovarian cancer patients.
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Affiliation(s)
| | | | | | | | | | - Ae Kyung Park
- School of Pharmacy, Jeonbuk National University, Jeonju 54896, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul 07804, Korea
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Kang E, Li Y, Kim B, Huh KY, Han M, Ahn JH, Sung HY, Park YS, Lee SE, Lee S, Park SK, Cho JY, Oh KH. Identification of Serum Metabolites for Predicting Chronic Kidney Disease Progression according to Chronic Kidney Disease Cause. Metabolites 2022; 12:1125. [PMID: 36422264 PMCID: PMC9696352 DOI: 10.3390/metabo12111125] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2022] [Revised: 11/03/2022] [Accepted: 11/10/2022] [Indexed: 12/01/2023] Open
Abstract
Early detection and proper management of chronic kidney disease (CKD) can delay progression to end-stage kidney disease. We applied metabolomics to discover novel biomarkers to predict the risk of deterioration in patients with different causes of CKD. We enrolled non-dialytic diabetic nephropathy (DMN, n = 124), hypertensive nephropathy (HTN, n = 118), and polycystic kidney disease (PKD, n = 124) patients from the KNOW-CKD cohort. Within each disease subgroup, subjects were categorized as progressors (P) or non-progressors (NP) based on the median eGFR slope. P and NP pairs were randomly selected after matching for age, sex, and baseline eGFR. Targeted metabolomics was performed to quantify 188 metabolites in the baseline serum samples. We selected ten progression-related biomarkers for DMN and nine biomarkers each for HTN and PKD. Clinical parameters showed good ability to predict DMN (AUC 0.734); however, this tendency was not evident for HTN (AUC 0.659) or PKD (AUC 0.560). Models constructed with selected metabolites and clinical parameters had better ability to predict CKD progression than clinical parameters only. When selected metabolites were used in combination with clinical indicators, random forest prediction models for CKD progression were constructed with AUCs of 0.826, 0.872, and 0.834 for DMN, HTN, and PKD, respectively. Select novel metabolites identified in this study can help identify high-risk CKD patients who may benefit from more aggressive medical treatment.
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Grants
- 2011E3300300, 2012E3301100, 2013E3301600, 2013E3301601, 2013E3301602, 2016E3300200, 2016E3300201, 2016E3300202, 2019E320100, 2019E320101, 2019E320102, and 2022-11-007 Korea Disease Control and Prevention Agency
- 2017M3A9E4044649 the Korean government (MSIT)
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Affiliation(s)
- Eunjeong Kang
- Department of Internal Medicine, Ewha Womans University Seoul Hospital, Ewha Womans University College of Medicine, Seoul 07804, Republic of Korea
| | - Yufei Li
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul 03080, Republic of Korea
| | - Bora Kim
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul 03080, Republic of Korea
- Laboratory of Metabolism, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Ki Young Huh
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul 03080, Republic of Korea
| | - Miyeun Han
- Department of Internal Medicine, National Medical Center, Seoul 04564, Republic of Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul 07804, Republic of Korea
| | - Hye Youn Sung
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul 07804, Republic of Korea
| | - Yong Seek Park
- Department of Microbiology, School of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Seung Eun Lee
- Department of Microbiology, School of Medicine, Kyung Hee University, Seoul 02447, Republic of Korea
| | - Sangjun Lee
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul 03080, Republic of Korea
| | - Sue K. Park
- Department of Preventive Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
- Cancer Research Institute, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
- Integrated Major in Innovative Medical Science, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
| | - Joo-Youn Cho
- Department of Clinical Pharmacology and Therapeutics, Seoul National University College of Medicine and Hospital, Seoul 03080, Republic of Korea
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul 03080, Republic of Korea
| | - Kook-Hwan Oh
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul 03080, Republic of Korea
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Sung HY, Choi EN, Han J, Chae YJ, Im SW, Kim HS, Park EM, Ahn JH. Protective role of ABCA1 in ischemic preconditioning is mediated by downregulation of miR-33-5p and miR-135-5p. Sci Rep 2021; 11:12511. [PMID: 34131232 PMCID: PMC8206355 DOI: 10.1038/s41598-021-91982-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 06/03/2021] [Indexed: 11/22/2022] Open
Abstract
Ischemic preconditioning (IPC) significantly reduces ischemia–reperfusion injury in the brain by inducing ischemic tolerance. Although emerging evidence suggests that microRNAs (miRNAs) contribute to the pathogenesis of brain ischemia and IPC-induced neuroprotection, the role of miRNAs and their underlying mechanisms are still unclear. IPC was induced in male C57BL/6 mice by brief bilateral common carotid artery occlusion. After 24 h, mice underwent transient middle cerebral artery occlusion followed by 3 h of reperfusion. Expression levels of messenger RNAs (mRNAs) and proteins were examined in the ipsilateral cortex, and mimics and inhibitors of selective miRNAs were transfected into Neuro-2a cells before oxygen–glucose deprivation (OGD). Post-IPC miRNA expression profiling identified neuroprotection-associated changes in miRNA expression in the ipsilateral cortex after ischemic stroke. Among them, miR-33-5p and miR-135b-5p were significantly downregulated by IPC. Inhibition of miR-33-5p and miR-135b-5p expression protected Neuro-2a cells from OGD-induced apoptosis. Inhibition of these two miRNAs significantly increased mRNA and protein levels of ATP-binding cassette subfamily A member 1 (ABCA1), and a binding assay showed that these two miRNAs showed specificity for Abca1 mRNA. Overexpression of ABCA1 decreased the Bax/Bcl2 mRNA ratio and activation of caspase-9 and caspase-3, whereas knockdown of ABCA1 expression increased the Bax/Bcl2 mRNA ratio and the percentage of Neuro-2a cells with a loss of mitochondrial membrane potential after OGD-treatment. In conclusion, ABCA1 expression is regulated by miR-33-5p and miR-135b-5p. Increased ABCA1 expression following IPC exerts a protective influence against cerebral ischemia via suppression of a mitochondria-dependent apoptosis pathway.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, College of Medicine, Ewha Womans University, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Korea
| | - Eun Nam Choi
- Department of Biochemistry, College of Medicine, Ewha Womans University, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Korea
| | - Jihye Han
- Department of Biochemistry, College of Medicine, Ewha Womans University, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Korea
| | - Yun Ju Chae
- Department of Biochemistry, College of Medicine, Ewha Womans University, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Korea
| | - Sun-Wha Im
- Genomic Medicine Institute, Medical Research Center, Seoul National University, Seoul, Korea
| | - Hee-Sun Kim
- Department of Molecular Medicine, College of Medicine, Ewha Womans University, Seoul, Korea
| | - Eun-Mi Park
- Department of Pharmacology, College of Medicine, Ewha Womans University, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Korea.
| | - Jung-Hyuck Ahn
- Department of Biochemistry, College of Medicine, Ewha Womans University, 25 Magokdong-ro 2-gil, Gangseo-gu, Seoul, 07804, Korea.
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Kim HJ, Kim HJ, Kim MK, Bae MK, Sung HY, Ahn JH, Kim YH, Kim SC, Ju W. SPSB1 enhances ovarian cancer cell survival by destabilizing p21. Biochem Biophys Res Commun 2019; 510:364-369. [PMID: 30712944 DOI: 10.1016/j.bbrc.2019.01.088] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2019] [Accepted: 01/19/2019] [Indexed: 11/20/2022]
Abstract
SPRY domain-containing SOCS box protein 1 (SPSB1) is an E3 ligase adaptor protein with unknown functions in cancer cells. In this study, we found that SPSB1 knockdown markedly decreased the viability and migration of ovarian cancer cells, while ectopic SPSB1 overexpression in IL-3-dependent Ba/F3 cells significantly increased their proliferation rate compared with empty vector-transfected cells. SPSB1 knockdown significantly elevated p21 protein and mRNA levels and induced apoptosis in ovarian cancer cells, as evidenced by increased levels of cleaved PARP and decreased levels of Bcl-2. Notably, mechanistic investigations revealed that SPSB1 accelerated p21 destabilization by directly interacting with p21 and promoting its ubiquitin-mediated proteasomal degradation. Taken together, our findings provide novel insights into the role of SPSB1 in ovarian cancer cells.
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Affiliation(s)
- Hyun-Jung Kim
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Hye Jin Kim
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea
| | - Mi-Kyung Kim
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea
| | - Moon Kyoung Bae
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Hye Youn Sung
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Yun Hwan Kim
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Seung Cheol Kim
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, College of Medicine, Ewha Womans University, Seoul, South Korea; Innovative Research Center for Control and Prevention of Women's Cancer, Ewha Womans University Mokdong Hospital, Seoul, South Korea.
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Sung HY, Lee JY, Park AK, Moon YJ, Jo I, Park EM, Wang KC, Phi JH, Ahn JH, Kim SK. Aberrant Promoter Hypomethylation of Sortilin 1: A Moyamoya Disease Biomarker. J Stroke 2018; 20:350-361. [PMID: 30309230 PMCID: PMC6186926 DOI: 10.5853/jos.2018.00962] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2018] [Accepted: 09/18/2018] [Indexed: 01/28/2023] Open
Abstract
BACKGROUND AND PURPOSE The pathogenesis of moyamoya disease (MMD) remains poorly understood, and no reliable molecular biomarkers for MMD have been identified to date. The present study aimed to identify epigenetic biomarkers for use in the diagnosis of MMD. METHODS We performed integrated analyses of gene expression profiles and DNA methylation profiles in endothelial colony forming cells (ECFCs) from three patients with MMD and two healthy individuals. Candidate gene mRNA expression and DNA methylation status were further validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and pyrosequencing analysis of an expanded ECFC sample set from nine patients with MMD and ten controls. We evaluated the diagnostic accuracy of the potential biomarkers identified here using receiver operating characteristic curve analyses and further measured major angiogenic factor expression levels using a tube formation assay and RT-qPCR. RESULTS Five candidate genes were selected via integrated analysis; all five were upregulated by hypomethylation of specific promoter CpG sites. After further validation in an expanded sample set, we identified a candidate biomarker gene, sortilin 1 (SORT1). DNA methylation status at a specific SORT1 promoter CpG site in ECFCs readily distinguished patients with MMD from the normal controls with high accuracy (area under the curve 0.98, sensitivity 83.33%, specificity 100%). Furthermore, SORT1 overexpression suppressed endothelial cell tube formation and modulated major angiogenic factor and matrix metalloproteinase-9 expression, implying SORT1 involvement in MMD pathogenesis. CONCLUSION s Our findings suggest that DNA methylation status at the SORT1 promoter CpG site may be a potential biomarker for MMD.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul, Korea
| | - Ji Yeoun Lee
- Department of Anatomy, Seoul National University College of Medicine, Seoul, Korea.,Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ae Kyung Park
- Suncheon National University College of Pharmacy, Suncheon, Korea
| | - Youn Joo Moon
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Inho Jo
- Department of Molecular Medicine, Ewha Womans University College of Medicine, Seoul, Korea
| | - Eun-Mi Park
- Department of Pharmacology, Ewha Womans University College of Medicine, Seoul, Korea
| | - Kyu-Chang Wang
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ji Hoon Phi
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, Ewha Womans University College of Medicine, Seoul, Korea
| | - Seung-Ki Kim
- Division of Pediatric Neurosurgery, Seoul National University Children's Hospital, Seoul National University College of Medicine, Seoul, Korea
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Ha YN, Sung HY, Yang SD, Chae YJ, Ju W, Ahn JH. Epigenetic modification of α- N-acetylgalactosaminidase enhances cisplatin resistance in ovarian cancer. Korean J Physiol Pharmacol 2017; 22:43-51. [PMID: 29302211 PMCID: PMC5746511 DOI: 10.4196/kjpp.2018.22.1.43] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 10/30/2017] [Accepted: 11/23/2017] [Indexed: 12/18/2022]
Abstract
Although cisplatin is one of the most effective antitumor drugs for ovarian cancer, the emergence of chemoresistance to cisplatin in over 80% of initially responsive patients is a major barrier to successful therapy. The precise mechanisms underlying the development of cisplatin resistance are not fully understood, but alteration of DNA methylation associated with aberrant gene silencing may play a role. To identify epigenetically regulated genes directly associated with ovarian cancer cisplatin resistance, we compared the expression and methylation profiles of cisplatin-sensitive and -resistant human ovarian cancer cell lines. We identified α-Nacetylgalactosaminidase (NAGA) as one of the key candidate genes for cisplatin drug response. Interestingly, in cisplatin-resistant cell lines, NAGA was significantly downregulated and hypermethylated at a promoter CpG site at position +251 relative to the transcriptional start site. Low NAGA expression in cisplatin-resistant cell lines was restored by treatment with a DNA demethylation agent, indicating transcriptional silencing by hyper-DNA methylation. Furthermore, overexpression of NAGA in cisplatin-resistant lines induced cytotoxicity in response to cisplatin, whereas depletion of NAGA expression increased cisplatin chemoresistance, suggesting an essential role of NAGA in sensitizing ovarian cells to cisplatin. These findings indicate that NAGA acts as a cisplatin sensitizer and its gene silencing by hypermethylation confers resistance to cisplatin in ovarian cancer. Therefore, we suggest NAGA may be a promising potential therapeutic target for improvement of sensitivity to cisplatin in ovarian cancer.
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Affiliation(s)
- Ye-Na Ha
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 07985, Korea
| | - Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 07985, Korea
| | - San-Duk Yang
- Department of Biomedical Sciences, Seoul National University, College of Medicine, Seoul 03080, Korea
| | - Yun Ju Chae
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 07985, Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University Seoul 07985, Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 07985, Korea
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Park MH, Kim S, Hwang H, Park H, Kwak J, Kwon EK, Sung HY, Han B. Positive Rates of Preliminary Crossmatches Among Transplantation Candidates Waitlisted for Different Organs in the Korean Network for Organ Sharing. Transplant Proc 2017; 48:2464-2466. [PMID: 27742323 DOI: 10.1016/j.transproceed.2016.02.086] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2015] [Accepted: 02/02/2016] [Indexed: 10/20/2022]
Abstract
OBJECTIVE For deceased-donor organ transplantations, negative T cell crossmatches (XMs) are mandatory for kidney and pancreas allocation in the Korean Network for Organ Sharing (KONOS) organ allocation system. Submission and periodic renewal of serum to the KONOS is required for all transplantation candidates of kidney or pancreas and these sera are distributed to 23 laboratories for preliminary XMs. We have investigated how sensitization status varies among transplantation candidates waitlisted for different organs. METHODS Positive rates of T cell XMs performed during recent 1-year period (from March 2014 to February 2015) in the Korea Organ Donation Agency laboratory have been analyzed according to different organs. For 163 cases of deceased donors, 3605 recipients (22.1 recipients per one donor) were crossmatched using both of National Institutes of Health and antihuman globulin complement-dependent cytotoxicity (CDC) methods and flow cytometry method. RESULTS T cell XM positive rates varied among transplantation candidates for different organs. The positive rate was high for kidney (485/3,145, 15.4%), and low for pancreas or kidney/pancreas (7/200, 3.5%), lung (0/41, 0%), and heart (11/221, 5.0%). Among XM-positive individuals, nearly two-thirds of the kidney transplantation candidates showed strong sensitization status with CDC+/flow+ results (64.5%), whereas pancreas or kidney/pancreas transplantation candidates more commonly showed weaker sensitization status with CDC-/flow+ results (85.7%). CONCLUSION Kidney transplantation candidates show a much higher positive rate and stronger sensitization status than candidates for other organs. The results of this study would be useful for determining the number of candidates to be crossmatched for different organs.
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Affiliation(s)
- M H Park
- Korea Organ Donation Agency Laboratory, Seoul, Korea.
| | - S Kim
- Korea Organ Donation Agency Laboratory, Seoul, Korea
| | - H Hwang
- Korea Organ Donation Agency Laboratory, Seoul, Korea
| | - H Park
- Korea Organ Donation Agency Laboratory, Seoul, Korea
| | - J Kwak
- Korea Organ Donation Agency Laboratory, Seoul, Korea
| | - E K Kwon
- Korea Organ Donation Agency Laboratory, Seoul, Korea
| | - H Y Sung
- Korea Organ Donation Agency Laboratory, Seoul, Korea
| | - B Han
- Korea Organ Donation Agency Laboratory, Seoul, Korea
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Sung HY, Yang SD, Park AK, Ju W, Ahn JH. Aberrant Hypomethylation of Solute Carrier Family 6 Member 12 Promoter Induces Metastasis of Ovarian Cancer. Yonsei Med J 2017; 58:27-34. [PMID: 27873492 PMCID: PMC5122649 DOI: 10.3349/ymj.2017.58.1.27] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 06/28/2016] [Accepted: 06/30/2016] [Indexed: 12/30/2022] Open
Abstract
PURPOSE Ovarian cancer (OC) is the most fatal of gynecological malignancies with a high rate of recurrence. We aimed to evaluate the expression of solute carrier family 6, member 12 (SLC6A12) and methylation of its promoter CpG sites in a xenograft mouse model of metastatic OC, and to investigate the regulatory mechanisms that promote aggressive properties during OC progression. MATERIALS AND METHODS Expression of SLC6A12 mRNA was determined by reverse-transcription quantitative polymerase chain reaction (RT-qPCR), and DNA methylation status of its promoter CpGs was detected by quantitative methylation-specific PCR. The metastatic potential of SLC6A12 was evaluated by in vitro migration/invasion transwell assays. Gene expression and DNA methylation of SLC6A12 and clinical outcomes were further investigated from publicly available databases from curatedOvarianData and The Cancer Genome Atlas. RESULTS SLC6A12 expression was 8.1-14.0-fold upregulated and its DNA methylation of promoter CpG sites was 41-62% decreased in tumor metastases. After treatment with DNA methyltransferase inhibitor and/or histone deacetylase inhibitor, the expression of SLC6A12 was profoundly enhanced (~8.0-fold), strongly supporting DNA methylation-dependent epigenetic regulation of SLC6A12. Overexpression of SLC6A12 led to increased migration and invasion of ovarian carcinoma cells in vitro, approximately 2.0-fold and 3.3-fold, respectively. The meta-analysis showed that high expression of SLC6A12 was significantly associated with poor overall survival [hazard ratio (HR)=1.07, p value=0.016] and that low DNA methylation levels of SLC6A12 at specific promoter CpG site negatively affected patient survival. CONCLUSION Our findings provide novel evidence for the biological and clinical significance of SLC6A12 as a metastasis-promoting gene.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea
| | - San Duk Yang
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
| | - Ae Kyung Park
- College of Pharmacy and Research Institute of Life and Pharmaceutical Sciences, Sunchon National University, Suncheon, Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Seoul, Korea.
| | - Jung Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea.
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Sung HY, Choi BO, Jeong JH, Kong KA, Hwang J, Ahn JH. Amyloid Beta-Mediated Hypomethylation of Heme Oxygenase 1 Correlates with Cognitive Impairment in Alzheimer's Disease. PLoS One 2016; 11:e0153156. [PMID: 27058954 PMCID: PMC4825942 DOI: 10.1371/journal.pone.0153156] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 03/24/2016] [Indexed: 01/02/2023] Open
Abstract
To identify epigenetically regulated genes involved in the pathogenesis of Alzheimer’s disease (AD) we analyzed global mRNA expression and methylation profiles in amyloid precursor protein (APP)-Swedish mutant-expressing AD model cells, H4-sw and selected heme oxygenase-1 (HMOX1), which is associated with pathological features of AD such as neurofibrillary tangles and senile plaques. We examined the epigenetic regulatory mechanism of HMOX1 and its application as a diagnostic and prognostic biomarker for AD. Our results show that HMOX1 mRNA and protein expression was approximately 12.2-fold and 7.9-fold increased in H4-sw cells, respectively. Increased HMOX1 expression was also detected in the brain, particularly the hippocampus, of AD model transgenic mice. However, the methylation of specific CpG sites within its promoter, particularly at CpG located −374 was significantly decreased in H4-sw cells. Treatment of neuroglioma cells with the demethylating agent 5-aza-2′-deoxycytidine resulted in reduced methylation of HMOX1 promoter accompanied by enhanced HMOX1 expression strongly supporting DNA methylation-dependent transcriptional regulation of HMOX1. Toxic Aβ-induced aberrant hypomethylation of HMOX1 at −374 promoter CpG site was correlated with increased HMOX1expression. In addition to neuroglioma cells, we also found Aβ-induced epigenetic regulation of HMOX1 in human T lymphocyte Jurkat cells. We evaluated DNA methylation status of HMOX1 at −374 promoter CpG site in blood samples from AD patients, patients with mild cognitive impairment (MCI), and control individuals using quantitative methylation-specific polymerase chain reaction. We observed lower methylation of HMOX1 at the −374 promoter CpG site in AD patients compared to MCI and control individuals, and a correlation between Mini-Mental State Examination score and demethylation level. Receiver operating characteristics analysis revealed good discrimination of AD patients from MCI patients and control individuals. Our findings suggest that the methylation status of HMOX1 at a specific promoter CpG site is related to AD progression.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Byung-Ok Choi
- Department of Neurology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | - Jee Hyang Jeong
- Department of Neurology, Ewha Womans University Mokdong Hospital, Seoul, Republic of Korea
| | - Kyoung Ae Kong
- Clinical Trial Center, Ewha Womans University Medical Center, Seoul, Republic of Korea
| | - Jinha Hwang
- Department of Biomedical Sciences, Seoul National University Graduate School, Seoul, Republic of Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
- Department of Biochemistry, Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
- * E-mail:
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Abstract
PURPOSE Both genetic and epigenetic alterations can lead to abnormal expression of metastasis-regulating genes in tumor cells. Recent studies suggest that aberrant epigenetic alterations, followed by differential gene expression, leads to an aggressive cancer cell phenotype. We examined epigenetically regulated genes that are involved in ovarian cancer metastasis. MATERIALS AND METHODS We developed SK-OV-3 human ovarian carcinoma cell xenografts in mice. We compared the mRNA expression and DNA methylation profiles of metastatic tissues to those of the original SK-OV-3 cell line. RESULTS Metastatic implants showed increased mRNA expression of the carbonic anhydrase 9 (CA9) gene and hypomethylation at CpG sites in the CA9 promoter. Treatment of wild-type SK-OV-3 cells with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine reduced methylation of the CA9 promoter and increased CA9 mRNA expression. Eight CpGs, which were located at positions -197, -74, -19, -6, +4, +13, +40, and +86, relative to the transcription start site, were hypomethylated in metastatic tumor implants, compared to that of wild-type SK-OV-3. Overexpression of CA9 induced an aggressive phenotype, including increased invasiveness and migration, in SK-OV-3 cells. CONCLUSION Alterations in the DNA methylation profile of the CA9 promoter were correlated with a more aggressive phenotype in ovarian cancer cells.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Seoul, Korea.
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea.
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Abstract
PURPOSE Recent discoveries suggest that aberrant DNA methylation provides cancer cells with advanced metastatic properties. However, the precise regulatory mechanisms controlling metastasis genes and their role in metastatic transformation are largely unknown. To address epigenetically-regulated gene products involved in ovarian cancer metastasis, we examined the mechanisms regulating mucin 13 (MUC13) expression and its influence on aggressive behaviors of ovarian malignancies. MATERIALS AND METHODS We injected SK-OV-3 ovarian cancer cells peritoneally into nude mice to mimic human ovarian tumor metastasis. Overexpression of MUC13 mRNA was detected in metastatic implants from the xenografts by expression microarray analysis and quantitative reverse-transcription polymerase chain reaction (qRT-PCR). The DNA methylation status within the MUC13 promoter region was determined using bisulfite sequencing PCR and quantitative methylation-specific PCR. We evaluated the effects of exogenous MUC13 on cell invasion and migration using in vitro transwell assays. RESULTS MUC13 mRNA expression was up-regulated, and methylation of specific CpG sites within the promoter was reduced in the metastatic implants relative to those in wild-type SK-OV-3 cells. Addition of a DNA methyltransferase inhibitor to SK-OV-3 cells induced MUC13 expression, thereby implying epigenetic regulation of MUC13 by promoter methylation. MUC13 overexpression increased migration and invasiveness, compared to control cells, suggesting aberrant up-regulation of MUC13 is strongly associated with progression of aggressive behaviors in ovarian cancer. CONCLUSION We provide novel evidence for epigenetic regulation of MUC13 in ovarian cancer. We suggest that the DNA methylation status within the MUC13 promoter region may be a potential biomarker of aggressive behavior in ovarian cancer.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea
| | - Ae Kyung Park
- College of Pharmacy, Sunchon National University, Suncheon, Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Seoul, Korea.
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Korea.
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Sung HY, Choi EN, Lyu D, Mook-Jung I, Ahn JH. Amyloid beta-mediated epigenetic alteration of insulin-like growth factor binding protein 3 controls cell survival in Alzheimer's disease. PLoS One 2014; 9:e99047. [PMID: 24964199 PMCID: PMC4070895 DOI: 10.1371/journal.pone.0099047] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2013] [Accepted: 05/11/2014] [Indexed: 12/30/2022] Open
Abstract
Swedish double mutation (KM670/671NL) of amyloid precursor protein (APP) is reported to increase toxic amyloid β (Aβ) production via aberrant cleavage at the β-secretase site and thereby cause early-onset Alzheimer's disease (AD). However, the underlying molecular mechanisms leading to AD pathogenesis remains largely unknown. Previously, our transcriptome sequence analyses revealed global expressional modifications of over 600 genes in APP-Swedish mutant-expressing H4 (H4-sw) cells compared to wild type H4 cells. Insulin-like growth factor binding protein 3 (IGFBP3) is one gene that showed significantly decreased mRNA expression in H4-sw cells. In this study, we investigated the functional role of IGFBP3 in AD pathogenesis and elucidated the mechanisms regulating its expression. We observed decreased IGFBP3 expression in the H4-sw cell line as well as the hippocampus of AD model transgenic mice. Treatment with exogenous IGFBP3 protein inhibited Aβ1–42- induced cell death and caspase-3 activity, whereas siRNA-mediated suppression of IGFBP3 expression induced cell death and caspase-3 cleavage. In primary hippocampal neurons, administration of IGFBP3 protein blocked apoptotic cell death due to Aβ1–42 toxicity. These data implicate a protective role for IGFBP3 against Aβ1–42-mediated apoptosis. Next, we investigated the regulatory mechanisms of IGFBP3 expression in AD pathogenesis. We observed abnormal IGFBP3 hypermethylation within the promoter CpG island in H4-sw cells. Treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine restored IGFBP3 expression at both the mRNA and protein levels. Chronic exposure to Aβ1–42 induced IGFBP3 hypermethylation at CpGs, particularly at loci −164 and −173, and subsequently suppressed IGFBP3 expression. Therefore, we demonstrate that expression of anti-apoptotic IGFBP3 is regulated by epigenetic DNA methylation, suggesting a mechanism that contributes to AD pathogenesis.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Eun Nam Choi
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Dahyun Lyu
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
| | - Inhee Mook-Jung
- Department of Biochemistry and Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
- Tissue Injury Defense Research Center, School of Medicine, Ewha Womans University, Seoul, Republic of Korea
- * E-mail:
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16
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Sung HY, Choi EN, Lyu D, Park AK, Ju W, Ahn JH. Aberrant hypomethylation-mediated AGR2 overexpression induces an aggressive phenotype in ovarian cancer cells. Oncol Rep 2014; 32:815-20. [PMID: 24920423 DOI: 10.3892/or.2014.3243] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2014] [Accepted: 03/30/2014] [Indexed: 11/06/2022] Open
Abstract
The metastatic properties of cancer cells result from genetic and epigenetic alterations that lead to the abnormal expression of key genes regulating tumor phenotypes. Recent discoveries suggest that aberrant DNA methylation provides cancer cells with advanced metastatic properties; however, the precise regulatory mechanisms controlling metastasis-associated genes and their roles in metastatic transformation are largely unknown. We injected SK-OV-3 human ovarian cancer cells into the perineum of nude mice to generate a mouse model that mimics human ovarian cancer metastasis. We analyzed the mRNA expression and DNA methylation profiles in metastasized tumor tissues in the mice. The pro-oncogenic anterior gradient 2 (AGR2) gene showed increased mRNA expression and hypomethylation at CpG sites in its promoter region in the metastatic tumor tissues compared with the cultured SK-OV-3 cells. We identified crucial cytosine residues at CpG sites in the AGR2 promoter region. Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine reduced the level of CpG methylation in the AGR2 promoter and increased the level of AGR2 expression. Next, we explored the functional role of AGR2 in the metastatic transformation of SK-OV-3 cells. SK-OV-3 cells overexpressing AGR2 showed increased migratory and invasive activity. Our results indicate that DNA methylation within the AGR2 promoter modulates more aggressive cancer cell phenotypes.
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Affiliation(s)
- Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 158-710, Republic of Korea
| | - Eun Nam Choi
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 158-710, Republic of Korea
| | - Dahyun Lyu
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 158-710, Republic of Korea
| | - Ae Kyung Park
- College of Pharmacy, Sunchon National University, Jeonnam 540-742, Republic of Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Seoul 158-710, Republic of Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Seoul 158-710, Republic of Korea
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17
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Kim NH, Sung HY, Choi EN, Lyu D, Choi HJ, Ju W, Ahn JH. Aberrant DNA methylation in the IFITM1 promoter enhances the metastatic phenotype in an intraperitoneal xenograft model of human ovarian cancer. Oncol Rep 2014; 31:2139-46. [PMID: 24676393 DOI: 10.3892/or.2014.3110] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 02/26/2014] [Indexed: 11/06/2022] Open
Abstract
A lack of reliable biomarkers for the early detection and risk of metastatic recurrences makes ovarian cancer the most lethal gynecological cancer. To understand the molecular mechanisms involved in ovarian cancer metastasis in vivo, we analyzed the transcriptional expression pattern in metastatic implants of human ovarian carcinoma xenografts in mice. The expression of 937 genes was significantly different, by at least 2-fold, in the xenografts compared with that in SK-OV-3 cells. We investigated the mechanisms that regulate the expression of one of the profoundly upregulated genes, interferon-induced transmembrane protein 1 (IFITM1), in the metastatic implants. Specific CpG sites within the IFITM1 promoter were hypomethylated in the metastatic implants relative to those in the wild-type SK-OV-3 cells. Treating wild-type SK-OV-3 cells with the demethylating agent 5-aza-2'-deoxycytidine enhanced IFITM1 expression in a dose-dependent manner, implying transcriptional regulation by promoter methylation. We also found that IFITM1 overexpression caused increased migration and invasiveness in SK-OV-3 cells. Our results demonstrate that IFITM1 could be a novel metastasis-promoting gene that enhances the metastatic phenotype in ovarian cancer via epigenetic transcriptional regulation. Our findings also suggest that the status of DNA methylation within the IFITM1 promoter region could be a biomarker indicating metastatic progression in ovarian cancer.
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Affiliation(s)
- Nam Hee Kim
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Yangcheon‑ku, Seoul 158-710, Republic of Korea
| | - Hye Youn Sung
- Department of Biochemistry, School of Medicine, Ewha Womans University, Yangcheon‑ku, Seoul 158-710, Republic of Korea
| | - Eun Nam Choi
- Department of Biochemistry, School of Medicine, Ewha Womans University, Yangcheon‑ku, Seoul 158-710, Republic of Korea
| | - Dahyun Lyu
- Department of Biochemistry, School of Medicine, Ewha Womans University, Yangcheon‑ku, Seoul 158-710, Republic of Korea
| | - Hyuck Jae Choi
- Department of Radiology and Research, Institute of Radiology, University of Ulsan, College of Medicine, Asan Medical Center, Songpa-ku, Seoul 138-736, Republic of Korea
| | - Woong Ju
- Department of Obstetrics and Gynecology, School of Medicine, Ewha Womans University, Yangcheon‑ku, Seoul 158-710, Republic of Korea
| | - Jung-Hyuck Ahn
- Department of Biochemistry, School of Medicine, Ewha Womans University, Yangcheon‑ku, Seoul 158-710, Republic of Korea
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Jo I, Park J, Sung HY, Lee JY, Kim HJ, Ahn J. Protein phosphatase 2A B56α mediates retinoic acid‐induced decreases in phosphorylation of endothelial nitric oxide synthase at serine 1179 and nitric oxide production. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1051.3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Inho Jo
- Molecular MedicineEwha Womans University Medical SchoolSeoulRepublic of Korea
| | - Jung‐Hyun Park
- Molecular MedicineEwha Womans University Medical SchoolSeoulRepublic of Korea
| | - Hye Youn Sung
- BiochemistryEwha Womans University Medical SchoolSeoulRepublic of Korea
| | - Jee Young Lee
- Molecular MedicineEwha Womans University Medical SchoolSeoulRepublic of Korea
| | - Hyun Jin Kim
- Molecular MedicineEwha Womans University Medical SchoolSeoulRepublic of Korea
| | - Jung‐Hyuck Ahn
- BiochemistryEwha Womans University Medical SchoolSeoulRepublic of Korea
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Kim KM, Sung HY, Jung B, Kang MS, Huh JY. HLA-B*40:179, a novel allele identified by sequence-based typing in cord blood from a Korean woman. ACTA ACUST UNITED AC 2012; 80:194-5. [PMID: 22607317 DOI: 10.1111/j.1399-0039.2012.01894.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
The novel allele B*40:179 showed one nucleotide difference with B*40:01:01 in exon 4.
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Affiliation(s)
- K M Kim
- Department of Laboratory Medicine, CHA Bundang Medical Center, CHA University, Seongnam, Gyeonggi-do, Korea
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Sung HY, Francis SE, Arnold ND, Holland K, Ernst V, Angyal A, Kiss-Toth E. Enhanced macrophage tribbles-1 expression in murine experimental atherosclerosis. Biology (Basel) 2012; 1:43-57. [PMID: 24832046 PMCID: PMC4011034 DOI: 10.3390/biology1010043] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 03/13/2012] [Accepted: 03/31/2012] [Indexed: 02/04/2023]
Abstract
Development of the atherosclerotic plaque involves a complex interplay between a number of cell types and an extensive inter-cellular communication via cell bound as well as soluble mediators. The family of tribbles proteins has recently been identified as novel controllers of pro-inflammatory signal transduction. The objective of this study was to address the expression pattern of all three tribbles proteins in atherosclerotic plaques from a mouse model of atherosclerosis. Each tribbles were expressed in vascular smooth muscle cells, endothelial cells as well as in resident macrophages of mouse atherosclerotic plaques. The role of IL-1 mediated inflammatory events in controlling tribbles expression was also addressed by inducing experimental atherosclerosis in ApoE−/−IL1R1−/− (double knockout) mice. Immunohistochemical analysis of these mice showed a selective decrease in the percentage of trb-1 expressing macrophages, compared to the ApoE−/− cohort (14.7% ± 1.55 vs. 26.3% ± 1.19). The biological significance of this finding was verified in vitro where overexpression of trb-1 in macrophages led to a significant attenuation (~70%) of IL-6 production as well as a suppressed IL-12 expression induced by a proinflammatory stimulus. In this in vitro setting, expression of truncated trb-1 mutants suggests that the kinase domain of this protein is sufficient to exert this inhibitory action.
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Affiliation(s)
- Hye Youn Sung
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
| | - Sheila E Francis
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
| | - Nadine D Arnold
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
| | - Karen Holland
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
| | - Vanessa Ernst
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
| | - Adrienn Angyal
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
| | - Endre Kiss-Toth
- Department of Cardiovascular Science, University of Sheffield, Sheffield, S10 2RX, UK.
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Sung HY, Choi EN, Ahn Jo S, Oh S, Ahn JH. Amyloid protein-mediated differential DNA methylation status regulates gene expression in Alzheimer’s disease model cell line. Biochem Biophys Res Commun 2011; 414:700-5. [DOI: 10.1016/j.bbrc.2011.09.136] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Accepted: 09/28/2011] [Indexed: 10/17/2022]
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Abstract
PURPOSE To identify genes responsible for the radiosensitivity, we investigated the role of the differential gene expression profiles by comparing radioresistant H1299 with radiosensitive H460 lung cancer cell lines. MATERIALS AND METHODS mRNA profiles of lung cancer cell lines were assessed using microarray, and subsequent validation was performed with qRT-PCR (Quantitative real time-polymerase chain reaction). The expression levels of differentially expressed genes were determined by Western blot and the radioresistance of lung cancer cell lines was measured by clonogenic assay. RESULTS From the differentially expressed apoptosis-related genes between H1299 and H460, we found Dcr3 (Decoy receptor 3, also known as TNFRSF6B; Tumour necrosis factor receptor super family member 6B) expression was significantly (P = 4.38 x 10(-7)) higher in H1299 cells than H460 cells. Moreover, the Dcr3 mRNA expression level in the radioresistant cell lines (H1299, A549, DLD1, MB231, MB157) was increased in comparison to the radiosensitive cell lines (ME180, Caski, U87MG, MCF7, H460). Overexpression of Dcr3 increased the survival rate of radiosensitive H460, MCF7, and U87MG cells, and knockdown of Dcr3 abolished the radioresistance of A549 cells. The survival rate of p53 (Tumour protein 53)-deficient H1299 after gamma-irradiation was not affected by the suppression of Dcr3 expression. However, when we introduced p53 into H1299 cells, siDcr3 (siRNA of Dcr3) suppressed the radioresistance of H1299 cells by inducing p53-dependent Fas (Fas receptor, also known as TNFRSF6; Tumour necrosis factor receptor super family member 6)-mediated apoptosis pathway. CONCLUSION Characterisation of gene expression profiles in two lung cancer cell lines revealed that Dcr3 expression and p53-dependent apoptosis signalling pathway regulate cellular response to ionising radiation.
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Affiliation(s)
- Hye Youn Sung
- Department of Biomedical Sciences, Biochemistry and Molecular Biology, Seoul National University College of Medicine, Seoul, Korea
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23
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Chae MJ, Sung HY, Kim EH, Lee M, Kwak H, Chae CH, Kim S, Park WY. Chemical inhibitors destabilize HuR binding to the AU-rich element of TNF-alpha mRNA. Exp Mol Med 2010; 41:824-31. [PMID: 19949288 DOI: 10.3858/emm.2009.41.11.088] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Hu protein R (HuR) binds to the AU-rich element (ARE) in the 3UTR to stabilize TNF-alpha mRNA. Here, we identified chemical inhibitors of the interaction between HuR and the ARE of TNF-alpha mRNA using RNA electrophoretic mobility gel shift assay (EMSA) and filter binding assay. Of 179 chemicals screened, we identified three with a half-maximal inhibitory concentration (IC(50)) below 10 microM. The IC(50) of quercetin, b-40, and b-41 were 1.4, 0.38, and 6.21 microM, respectively, for binding of HuR protein to TNF-alpha mRNA. Quercetin and b-40 did not inhibit binding of tristetraprolin to the ARE of TNF-alpha mRNA. When LPS-treated RAW264.7 cells were treated with quercetin and b-40, we observed decreased stability of TNF-alpha mRNA and decreased levels of secreted TNF-alpha. From these results, we could find inhibitors for the TNF-alpha mRNA stability, which might be used advantageously for both the study for post-transcriptional regulation and the discovery of new anti-inflammation drugs.
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Affiliation(s)
- Min-Ju Chae
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Korea
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Gilby DC, Sung HY, Winship PR, Goodeve AC, Reilly JT, Kiss-Toth E. Tribbles-1 and -2 are tumour suppressors, down-regulated in human acute myeloid leukaemia. Immunol Lett 2009; 130:115-24. [PMID: 20005259 DOI: 10.1016/j.imlet.2009.12.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2009] [Revised: 11/26/2009] [Accepted: 12/02/2009] [Indexed: 12/17/2022]
Abstract
Constitutive MAPK signalling is observed in approximately 50% of acute myeloid leukaemia (AML) cases. JNK activation in particular is associated with treatment failure in AML. Tribbles proteins (trb-1, trb-2 and trb-3) are potent negative regulators of MAPK pathways influencing apoptosis, differentiation and cell-cycle progression. Here we aimed to examine tribbles gene expression in AML and to characterise their role in leukaemic cells. A microarray dataset was interrogated for tribbles expression levels in AML cases and healthy controls. Myeloid cell proliferation and apoptosis were assayed in response to trb-1/trb-2 gene knockdown and overexpression, as well as a physical and functional interaction between trb and C/EBPalpha. Trb-2 expression was reduced in AML compared to healthy controls (correlating with nucleophosmin (NPM1) mutations), while low trb-1 expression was associated with inactive C/EBPalpha. In vitro assays indicated that trb-1/trb-2 are growth restrictive and pro-apoptotic in Me-1 cells, each capable of inhibiting JNK activation. JNK inactivation was itself associated with reduced Bcl-2 Ser70 phosphorylation, a residue which, when phosphorylated, maintains the anti-apoptotic activity of Bcl-2. Consistent with this, tribbles-mediated dephosphorylation of Bcl-2 Ser70 was associated with subsequent apoptosis. Trb-1/trb-2 transcription appeared to be moderately C/EBPalpha-responsive, and physical interaction between C/EBPalpha and trb-1/trb-2 was observed, suggesting a potential for auto-regulation of trb-1 and trb-2 transcription. In conclusion, we propose that trb-1 and trb-2 tumour suppressor activity may be abrogated in a proportion of AML patients. This may lead to enhanced cell survival, and therefore contribute to pathogenesis of the disease. Trb-1/trb-2 may, therefore, represent useful therapeutic targets for the treatment of AML in patients with dys-regulated trb activity.
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Affiliation(s)
- Daniel C Gilby
- Department of Cardiovascular Science, University of Sheffield, Sheffield, United Kingdom
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Park JH, Jin JY, Baek WK, Park SH, Sung HY, Kim YK, Lee J, Song DK. Ambivalent role of gallated catechins in glucose tolerance in humans: a novel insight into non-absorbable gallated catechin-derived inhibitors of glucose absorption. J Physiol Pharmacol 2009; 60:101-109. [PMID: 20065503] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 10/20/2008] [Accepted: 11/06/2009] [Indexed: 05/28/2023]
Abstract
Prolonged postprandial hyperglycemia is a detrimental factor for type 2 diabetes and obesity. The benefit of green tea extract (GTE) consumption still requires confirmation. We report the effects of circulating green tea catechins on blood glucose and insulin levels. Oral glucose loading 1 h after GTE ingestion in humans led to higher blood glucose and insulin levels than in control subjects. Gallated catechins were required for these effects, although within the intestinal lumen they have been known to decrease glucose and cholesterol absorption. Treatment with epigallocatechin-3-gallate hindered 2-deoxyglucose uptake into liver, fat, pancreatic beta-cell, and skeletal muscle cell lines. The glucose intolerance was ameliorated by gallated catechin-deficient GTE or GTE mixed with polyethylene glycol, which was used as an inhibitor of intestinal absorption of gallated catechins. These findings may suggest that the gallated catechin when it is in the circulation elevates blood glucose level by blocking normal glucose uptake into the tissues, resulting in secondary hyperinsulinemia, whereas it decreases glucose entry into the circulation when they are inside the intestinal lumen. These findings encourage the development of non-absorbable derivatives of gallated catechins for preventative treatment of type 2 diabetes and obesity, which would specifically induce only the positive luminal effect.
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Affiliation(s)
- J H Park
- Department of Physiology and Chronic Disease Research Center, Daegu, Korea
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26
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Abstract
We describe a case of esophageal perforation that resulted from a fishbone. A 71-year-old man had had a fishbone impacted in the lower esophagus for 2 days. At presentation, the bone was dislodged at endoscopy; one round opening in a deep ulceration was detected when the fishbone was removed. The perforation was closed by endoscopic hemoclipping, after the removal of the fishbone. A thoracic computed tomography revealed air around the esophagus, aorta and bronchus and the presence of a pleural effusion. These findings suggested mediastinal emphysema and mediastinitis due to the esophageal perforation after the removal of the fishbone. Esophagography revealed a focal esophageal defect and linear contrast leakage at the distal esophagus. The mediastinal emphysema and pleural effusion successfully resolved after the endoscopic hemoclip application and conservative management of the perforation.
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Affiliation(s)
- H Y Sung
- Division of Gastroenterology, Department of Internal Medicine, Catholic University of Korea, Seoul, Korea
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27
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Sung HY, Guan H, Czibula A, King AR, Eder K, Heath E, Suvarna SK, Dower SK, Wilson AG, Francis SE, Crossman DC, Kiss-Toth E. Human tribbles-1 controls proliferation and chemotaxis of smooth muscle cells via MAPK signaling pathways. J Biol Chem 2007; 282:18379-18387. [PMID: 17452330 PMCID: PMC2366084 DOI: 10.1074/jbc.m610792200] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Migration and proliferation of smooth muscle cells are key to a number of physiological and pathological processes, including wound healing and the narrowing of the vessel wall. Previous work has shown links between inflammatory stimuli and vascular smooth muscle cell proliferation and migration through mitogen-activated protein kinase (MAPK) activation, although the molecular mechanisms of this process are poorly understood. Here we report that tribbles-1, a recently described modulator of MAPK activation, controls vascular smooth muscle cell proliferation and chemotaxis via the Jun kinase pathway. Our findings demonstrate that this regulation takes place via direct interactions between tribbles-1 and MKK4/SEK1, a Jun activator kinase. The activity of this kinase is dependent on tribbles-1 levels, whereas the activation and the expression of MKK4/SEK1 are not. In addition, tribbles-1 expression is elevated in human atherosclerotic arteries when compared with non-atherosclerotic controls, suggesting that this protein may play a role in disease in vivo. In summary, the data presented here suggest an important regulatory role for trb-1 in vascular smooth muscle cell biology.
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Affiliation(s)
- Hye Youn Sung
- Cardiovascular Research Unit, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Hongtao Guan
- Section of Infection, Inflammation and Immunity, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Agnes Czibula
- Institute of Genetics, Biological Research Centre, H-6701 Szeged, Hungary
| | - Andrea R King
- Cardiovascular Research Unit, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Katalin Eder
- Institute of Biochemistry, Biological Research Centre, H-6701 Szeged, Hungary
| | - Emily Heath
- Cardiovascular Research Unit, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - S Kim Suvarna
- Department of Histopathology, Northern General Hospital, Sheffield S5 7AU, United Kingdom
| | - Steven K Dower
- Section of Infection, Inflammation and Immunity, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Anthony G Wilson
- Section of Infection, Inflammation and Immunity, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Sheila E Francis
- Cardiovascular Research Unit, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - David C Crossman
- Cardiovascular Research Unit, University of Sheffield, Sheffield S10 2TN, United Kingdom
| | - Endre Kiss-Toth
- Cardiovascular Research Unit, University of Sheffield, Sheffield S10 2TN, United Kingdom.
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Sung HY, Francis SE, Crossman DC, Kiss-Toth E. Regulation of expression and signalling modulator function of mammalian tribbles is cell-type specific. Immunol Lett 2006; 104:171-7. [PMID: 16364454 DOI: 10.1016/j.imlet.2005.11.010] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2005] [Revised: 11/11/2005] [Accepted: 11/11/2005] [Indexed: 10/25/2022]
Abstract
The constant need to respond to changes in the environment is a common feature for all life forms. During evolution, a number of intracellular signal processing systems have evolved to fulfill this requirement. One of the most ancient such systems is the mitogen activated protein kinase (MAPK) signalling network, shared by all eukaryotes. Activation of MAPKs is key to regulation of mitosis and in cellular responses to stress or hormones, for instance. In addition, activity of this signalling system is essential during embryonic development. However, many aspects of MAPK mediated responses are strongly cell-type specific. A family of proteins, called tribbles have recently been described as novel regulators of MAPK function. Our group has previously shown that alterations in tribbles levels lead to profound changes in the activation of the various MAPKs. However, little is known about the cell-type specific aspects of regulation of tribbles expression. Here, we report that expression of all three members of the human tribbles family is dynamically controlled in response to inflammatory stimulation. This regulation, however, is strongly cell-type dependent. Our observations suggest regulation of tribbles expression may play an important role in the cell-type specific cellular responses, mediated by the MAPK network.
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Affiliation(s)
- H Y Sung
- Cardiovascular Research Unit, Division of Clinical Sciences (North), University of Sheffield, Sheffield S5 7AU, United Kingdom
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Abstract
OBJECTIVES To determine associations between advancing age and screening behavior and prognosis in long-term members of a prepaid health plan diagnosed with invasive cervical cancer (ICC). DESIGN Case series. SETTING Prepaid health plan. PARTICIPANTS All women diagnosed with ICC at Kaiser Permanente Medical Care Program-Northern California health plan from 1988 to 1994. MEASUREMENTS From medical records, we recorded participants' age, stage at diagnosis, tumor histology, and results of and reasons for all previous cervical smears. We limited our analysis to women who had been members of the health plan for at least 30 of the 36 months preceding diagnosis (n = 455). RESULTS Women in older age groups were less likely than younger women to have been screened within the 3 years before diagnosis (P = .005 for trend). Nonadherence to follow-up of abnormal cervical smears was uncommon (17/455, 3.7%) and not age related (P = .932 for trend). The proportions of ICC that were interval cancers, defined as ICC diagnosed within 3 years of a negative screening smear, were highest in women under age 30 (P = .004 for trend). In multivariate analyses controlling for stage at diagnosis, women age 60 and older were not more likely to die of ICC within 3 years of diagnosis than were women younger than age 60 (odds ratio 1.30, 95% confidence interval 0.75-2.28). CONCLUSION The disproportionate burden of cervical cancer observed in older women appears to be largely attributable to lack of screening within the 3 years before diagnosis.
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Affiliation(s)
- G F Sawaya
- Department of Obstetrics, Gynecology and Reproductive Sciences, University of California, San Francisco, 94143, USA
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30
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Abstract
A mutant of Bacillus subtilis IMR-NK1, which is used for the production of domestic "natto" in Taiwan, produced high fibrinolytic enzyme activity by solid-state fermentation using wheat bran as medium. In addition, a strong fibrinolytic enzyme was purified from the cultivation media. The purified enzyme was almost homogeneous, as examined by SDS-PAGE and capillary electrophoresis. The enzyme had an optimal pH of 7.8, an optimal temperature of 55 degrees C, and a K(m) of 0.15% for fibrin hydrolysis. The molecular mass estimated by gel filtration was 31.5 kDa, and the isoelectric point estimated by isoelectric focusing electrophoresis was 8.3. The enzyme also showed activity for hydrolysis of fibrinogen, casein, and several synthetic substrates. Among the synthetic substrates, the most sensitive substrate was N-succinyl-Ala-Ala-Pro-Phe-pNA. PMSF and NBS almost completely inhibited the activity of the enzyme. These results indicate that the enzyme is a subtilisin-like serine protease, similar to nattokinase from Bacillus natto.
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Affiliation(s)
- C T Chang
- Department of Food and Nutrition, Providence University, Shalu, Taiwan, Republic of China
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31
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Abstract
BACKGROUND The first nicotine replacement product, Nicorette Gum, was marketed in 1984 as an adjuvant to help smokers quit smoking. In 1992, sales of nicotine patches were begun. Before 1996, nicotine gums and nicotine patches were prescribed by physicians and supplemented with behavioural counselling. Since 1996, nicotine gums and patches became available over the counter. OBJECTIVES To examine the effect of sales of nicotine replacement products on national cigarette consumption. DESIGN National time series quarterly cigarette consumption, sales of nicotine gums and patches data between 1976 and 1998 are used to estimate a time series autoregressive moving average intervention model. PARTICIPANTS National reported statistics. MAIN OUTCOME MEASURES Per capita cigarette sales. RESULTS A 10% increase in sales of nicotine replacement products will lead to a 0.04% reduction in cigarette sales. The model indicates that a 0.076% reduction in cigarette consumption is associated with the availability of nicotine patches after 1992. The over the counter dummy variable (after 1996) has a negative sign, but is not significant, perhaps due to only a few quarters of data in the study period. CONCLUSIONS Nicotine replacement products (nicotine gums and nicotine patches) play a significant role in reducing cigarette consumption, in addition to the negative effect of increasing cigarette price and the overall trend of declining cigarette consumption (as reflected by the time trend variable). The findings of this study suggest that additional efforts for promoting sales of nicotine replacement products will be another effective alternative to discouraging cigarette consumption.
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Affiliation(s)
- T Hu
- School of Public Health, University of California, Berkeley 94720, USA.
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Sung HY, Kearney KA, Miller M, Kinney W, Sawaya GF, Hiatt RA. Papanicolaou smear history and diagnosis of invasive cervical carcinoma among members of a large prepaid health plan. Cancer 2000; 88:2283-9. [PMID: 10820350] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
BACKGROUND Despite the widespread use of Papanicolaou (Pap) smear screening, substantial morbidity and mortality from cervical carcinoma continue in the U.S. Although access to screening is a major barrier to use of the Pap smear, invasive cervical carcinoma (ICC) still is observed in health plan members who have comprehensive preventive care coverage. METHODS For all women diagnosed with ICC between 1988 and 1994 in a large prepaid health plan, the authors retrospectively reviewed the medical records for prediagnosis Pap smear history to identify antecedents to ICC. RESULTS Of 642 women diagnosed as having ICC, 455 (71%) had been plan members for > or = 30 of the 36 months before diagnosis. Of these 455 women, 240 (53%) had no Pap smear during the 6-36 months prior to diagnosis (i.e., were nonadherent to screening), 127 (28%) had only "normal" Pap smear results, 42 (9%) had at least 1 abnormal Pap smear and were adequately followed, 17 (4%) had at least 1 abnormal result without adequate follow-up, and 29 (6%) were classified as "other." Compared with adherent women, more nonadherent women presented with later stage disease, were symptomatic at the time of diagnosis, were older, and were of a race/ethnicity other than non-Hispanic white. CONCLUSIONS Nonadherence to screening recommendations was found to be the most important modifiable antecedent to ICC in this population. The rate of incidence of ICC could be reduced by interventions to increase screening in women who do not have Pap smears regularly and by the use of newer screening technologies to reduce the false-negative rate of Pap smears.
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Affiliation(s)
- H Y Sung
- Department of Quality and Utilization, Kaiser Permanente Medical Care Program, Oakland, California 94612, USA
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Kinney W, Sung HY, Kearney KA, Miller M, Sawaya G, Hiatt RA. Missed opportunities for cervical cancer screening of HMO members developing invasive cervical cancer (ICC). Gynecol Oncol 1998; 71:428-30. [PMID: 9887244 DOI: 10.1006/gyno.1998.5135] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
OBJECTIVE To identify potential missed opportunities and to suggest interventions for cervical cancer screening in members of a prepaid health plan by examining the membership histories and medical records of women who had no Pap smear performed in the 3 years prior to the diagnosis of ICC. METHODS Medical records of all 642 members of a prepaid health plan developing ICC during the period from 1988 to 1994 were reviewed and details of patient interaction with the health care system were abstracted. Assessment of screening history and history of clinic visits was limited to the period 36 months prior to diagnosis, but excluded the last 6 months prior to diagnosis, so as to avoid including smears or visits which were part of the evaluation that led to the recognition of ICC. RESULTS Of women developing ICC, 384/642 (60%) had not had a smear in the period from 36 months to 6 months preceding the diagnosis. Of these 384 unscreened women, 241 (63%) had been insured by our HMO for at least 30 of the 36 months prior to diagnosis. Contact with the medical system in one of the primary care outpatient clinics was documented in 180/241 (75%) of these long-standing members during the specified period. Considering only Internal Medicine and Family Practice clinic visits, 169/241 (70%) had been seen at least once and 101/241 (42%) had been seen 3 or more times. CONCLUSION Most long-standing HMO members developing ICC without benefit of recent Pap smear screening were seen in primary care outpatient clinics in the 3 years preceding their diagnosis.
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Affiliation(s)
- W Kinney
- Division of Gynecologic Oncology, Permanente Medical Group, Oakland, California, 95815, USA
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Abstract
beta-N-Acetylhexosaminidase was purified from the extract of cabbage by sequential steps of ammonium sulfate fractionation, chromatofocusing, DEAE-Sepharose CL-6B ion exchange chromatography and Sephacryl S-200 HR gel filtration. By these steps, the purity of the enzyme increased by 256 fold with a recovery of 8%. The purified enzyme was homogeneous as examined by native PAGE. It showed an optimal pH of 4, an optimal temperature of 60 degrees C and a Km of 0.94 mM for hydrolysis of pNp-beta-GlcNAc. The molecular mass of the enzyme determined from filtration through Sephacryl S-200 was 150 kDa. Three subunits with molecular mass of 64, 57 and 51 kDa were observed as determined by SDS-PAGE. NBS (0.025 mM), DEPC (3 mM) and WRK (30 mM) significantly inhibited the activity of the enzyme. The enzyme also showed activity toward pNp-beta-GalNAc, N,N'-diacetylchitobiose, N,N',N"-triacetylchitotriose and N,N',N",N"'-tetraacetyl chitotetraose but showed no activity toward pNp-alpha-GlcNAc, chitin and ethylene glycol chitin.
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Affiliation(s)
- C T Chang
- Department of Food and Nutrition, Providence University, Shalu, Taiwan, R.O.C
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Abstract
OBJECTIVES To determine (1) the number and proportion of Americans living with chronic conditions, and (2) the magnitude of their costs, including direct costs (annual personal health expenditures) and indirect costs to society (lost productivity due to chronic conditions and premature death). DESIGN Analysis of the 1987 National Medical Expenditure Survey for prevalence and direct health care costs; indirect costs based on the 1990 National Health Interview Survey and Vital Statistics of the United States. SETTING US population. PARTICIPANTS For the estimate of prevalence and direct costs, the National Medical Expenditure Survey sample of persons who reported health conditions associated with (1) use of health services or supplies or (2) periods of disability. INTERVENTIONS None. MAIN OUTCOME MEASURES The number of persons with chronic conditions, their annual direct health care costs, and indirect costs from lost productivity and premature deaths. RESULTS In 1987, 90 million Americans were living with chronic conditions, 39 million of whom were living with more than 1 chronic condition. Over 45% of noninstitutionalized Americans have 1 or more chronic conditions and their direct health care costs account for three fourths of US health care expenditures. Total costs projected to 1990 for people with chronic conditions amounted to $659 billion--$425 billion for direct health care costs and $234 billion in indirect costs. CONCLUSIONS The prevalence and costs of chronic conditions as a whole have rarely been estimated. Because the number of persons with limitations due to chronic conditions is more regularly reported in the literature, the total prevalence of chronic conditions has perhaps been minimized. The majority of persons with chronic conditions are not disabled, nor are they elderly. Chronic conditions affect all ages. Because persons with chronic conditions have greater health needs at any age, their costs are disproportionately high.
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Affiliation(s)
- C Hoffman
- Institute for Health and Aging at the University of California, San Francisco, USA
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36
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Chang CT, Hsueh YL, Sung HY. Purification and properties of chitinase from cabbage stems with roots. Biochem Mol Biol Int 1996; 40:417-25. [PMID: 8896765 DOI: 10.1080/15216549600201922] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Chitinase has been purified from the extract of cabbage stems with roots through successive steps of ammonium sulfate fractionation, Sephadex G-75 gel filtration, chromatofocusing and Sephacryl S-200 HR gel filtration. By these steps, the purity of the enzyme increased by 63 fold and the recovery of the enzyme activity was 18%. The purified enzyme was homogeneous when analyzed by SDS-PAGE. It showed an optimal pH of 6 and optimal temperature of 60 degrees C for hydrolysis of ethylene glycol chitin (EGC). The molecular mass of the enzyme was 41 kDa, as determined by SDS-PAGE. Heavy metal ions (1.5 mM) Ag+, Hg2+ and Fe2+, and chemical modification agents NAI (1 mM), NBS (0.5 mM) and CHD (0.5 mM) significantly or completely inhibited the activity of the enzyme. Substrate EGC at high concentrations also inhibited the activity. BSA (0.05%), Triton X-100 (0.5%) and glycerol (50%) provided significant protection of the enzyme from freezing inactivation.
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Affiliation(s)
- C T Chang
- Department of Food and Nutrition, Providence University, Shalu, Taiwan, R.O.C
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Keeler TE, Hu TW, Barnett PG, Manning WG, Sung HY. Do cigarette producers price-discriminate by state? An empirical analysis of local cigarette pricing and taxation. J Health Econ 1996; 15:499-512. [PMID: 10164041 DOI: 10.1016/s0167-6296(96)00498-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
This study analyzes the interactive effects of oligopoly pricing, state taxation, and anti-smoking regulations on retail cigarette prices by state, using panel data for the 50 US states between 1960 and 1990. The results indicate that cigarette producers do price-discriminate by state, though the effect is not large relative to the final retail price. There are two further results: (1) state taxes are more than passed on - a 1-cent state tax increase results in a price increase of 1.11 cents, and (2) sellers offset state and local anti-smoking laws with lower prices, thereby blunting effects of the regulations.
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Affiliation(s)
- T E Keeler
- Department of Economics, University of California, Berkeley 94720, USA
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Huang JW, Chen JT, Yu WP, Shyur LF, Wang AY, Sung HY, Lee PD, Su JC. Complete structures of three rice sucrose synthase isogenes and differential regulation of their expressions. Biosci Biotechnol Biochem 1996; 60:233-9. [PMID: 9063969 DOI: 10.1271/bbb.60.233] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
By cloning and sequencing cDNA and genomic DNA and transcription initiation site mapping, the total structures including at least 1 kb of putative regulatory sequences upstream of the transcription initiation sites of three genes encoding rice sucrose synthase isoprotomers were either newly established or amended. The third type of SS gene, RSus3, has not been found in other plants. The structures of the three genes and the gene products were compared and their evolutionary sequence was proposed. Specific probes for the three SS mRNA's were developed and used for analyzing their steady state levels at different organs and under some physiological stress conditions. It appears that RSus2 is a house-keeping gene, RSus3 is highly specific to the grain, and the expression of RSus1 shows a tendency to complement that of RSus3. A possible cause of the presence of the third rice SS gene was discussed. We also reported a novel method to synthesize single-stranded DNA for S1 mapping of a transcription initiation site associated with extended secondary structures.
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Affiliation(s)
- J W Huang
- Department of Agricultural Chemistry, National Taiwan University, Taipei
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39
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Abstract
OBJECTIVES The purpose of this study was to examine the relative effects of taxation vs an anti-smoking media campaign on cigarette consumption in California. METHODS Quarterly cigarette sales data reported by the California State Board of Equalization between 1980 and 1992 were used to estimate a time-series model, adjusted for seasonal variations and time trends. RESULTS The estimated results show that sales of cigarettes were reduced by 819 million packs from the third quarter of 1990 through the fourth quarter of 1992 owing to an additional 25-cent state tax increase, while the anti-smoking media campaign reduced the cigarette sales by 232 million packs during the same period. CONCLUSIONS Both taxation and anti-smoking media campaigns are effective means of reducing cigarette consumption. The strength of those effects, however, is influenced by the magnitude of the taxes and the amount of media campaign expenditures.
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Affiliation(s)
- T W Hu
- School of Public Health, University of California, Berkeley 94720, USA
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40
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Wu JS, Sung HY, Juang RH. Transformation of cadmium-binding complexes during cadmium sequestration in fission yeast. Biochem Mol Biol Int 1995; 36:1169-75. [PMID: 8535288] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Fission yeast responded to environmental cadmium by producing a family of small Cd-binding peptides, phytochelatins (PCn). A low molecular weight (LMW) complex essentially composed of PC2, and PC3 was produced and then disappeared gradually in 24 hrs after Cd treatment, which served as a transient form for a temporary but quick relief of Cd in the cytosoL It had been reported that the LMW complex was further transported into the vacuole by an ABC-type protein (HMT1), and a higher molecular weight (HMW) complex was formed in the vacuole. Results from gel filtration chromatography and HPLC analysis showed that the transformation of the LMW to the HMW complex was accompanied with a rearrangement of its PCn component. Besides, the molecular conformation of the HMW complex changed from a relaxed form in the early stage to a more condensed conformation during cell aging. And the transformation of the LMW into the HMW complex by the addition of sulfide in the test tube was demonstrated.
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Affiliation(s)
- J S Wu
- Department of Agricultural Chemistry, National Taiwan University, Taipei
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41
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Hu TW, Sung HY, Keeler TE. The state antismoking campaign and the industry response: the effects of advertising on cigarette consumption in California. Am Econ Rev 1995; 85:85-90. [PMID: 10160516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Affiliation(s)
- T W Hu
- School of Public Health, University of California, Berkeley, 94720, USA
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42
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Yen SF, Su JC, Sung HY. Purification and characterization of rice sucrose synthase isozymes. Biochem Mol Biol Int 1994; 34:613-620. [PMID: 7833839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
From an extract of milk-ripe stage rice grains, four sucrose synthase activities could be separated by a FPLC Mono Q column. They are considered isozymes because they show different electrophoretic mobilities in a non-denaturing gel. However, the migration rates of their subunits in SDS-PAGE were indistinguishable and had a molecular mass of 94 kDa. The native forms had identical molecular mass of 440 kDa, thus they were considered to be tetrameric but carrying different ionic charges. Ouchterlony assay indicates that they have the same epitopes. All isozymes use UDP as the best nucleoside diphosphate substrate. When characterized by the ratio of catalytic rates of sucrose synthesizing and cleaving reactions, the isozyme that had the slowest migration rate in PAGE had the smallest value.
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Affiliation(s)
- S F Yen
- Department of Agricultural Chemistry, National Taiwan University, Taipei, R.O.C
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43
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Charng YY, Juang RH, Su JC, Sung HY. Partial purification and characterization of invertase isozymes from rice grains (Oryza sativa). Biochem Mol Biol Int 1994; 33:607-15. [PMID: 7951078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Four invertase isozymes have been isolated from the milky stage rice grains. According to the pH optima, they are classified as one alkaline (IT7) and three acid invertases. The acid invertases are further divided into two soluble forms (IT4 and IT5) and one cell wall-bound (ITb) form which was solubilized in 1 M NaCl. The pH optima of ITb, IT4, IT5 and IT7 are 4.5, 3.5-4.0, 5.0 and 7.0, and the molecular masses are 42, 60, 64 and 260 kDa, respectively. Both IT4 and IT5 were bound to Con A-Sepharose suggesting that these enzymes are glycoprotein. The Km of ITb, IT4, IT5 and IT7 for sucrose are 4.3, 0.9, 12.1 and 70.1 mM, respectively. IT4 and IT5 have a higher Km for raffinose, and the maximum activities are 64% and 27% of that using sucrose as the substrate. IT7 did not hydrolyze raffinose at all. These invertases also exhibit distinct isoelectric points (pI) and different susceptibility to various inhibitors.
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Affiliation(s)
- Y Y Charng
- Department of Agricultural Chemistry, National Taiwan University, Taipei, R.O.C
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Scheffler RM, Clement DG, Sullivan SD, Hu TW, Sung HY. The hospital response to Medicare's Prospective Payment System: an econometric model of Blue Cross and Blue Shield plans. Med Care 1994; 32:471-85. [PMID: 8182975 DOI: 10.1097/00005650-199405000-00006] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
This paper presents an empirical analysis of the impact that resulted from phase-in of Medicare's Prospective Payment System (PPS) on hospital utilization and payments for the Blue Cross and Blue Shield (BCBS) plans. A pooled cross-sectional time series econometric model was specified and estimated using quarterly hospital utilization and payments of the BCBS plans over the period 1980 to 1987. The results indicate that the implementation of PPS was significantly associated with a lower rate of hospital admissions, days and deflated inpatient payments for the BCBS plan members under age 65. A 1% increase in the proportion of hospital days reimbursed under PPS resulted in a .032% decrease in BCBS plan admissions per 1,000 members, a 0.017% decline in days per 1,000 members and a 0.016% decline in deflated inpatient payment per 1,000 members. The reductions in hospital utilization resulted in lower payments by BCBS plans to participating hospitals suggesting a positive spill-over effect of PPS for private insurers. This research underscores the importance of interaction between federal health policy and the private health insurance market.
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Affiliation(s)
- R M Scheffler
- School of Public Health, University of California at Berkeley 94820
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45
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Lin SS, Sung HY. Partial purification and characterization of soluble acid invertases from rice (Oryza sativa) leaves. Biochem Mol Biol Int 1993; 31:945-53. [PMID: 8136712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
There are three soluble acid invertases in the leaves of rice. They could be separated by DEAE1-Sephacel chromatography, and named IT1, IT2 and IT3. The molecular weights of IT1, IT2 and IT3, determined by HPLC gel filtration chromatography, were 220 kD, 59 kD and 67 kD, respectively. Their pI values were 6.2, 5.2 and 4.9, respectively. The pH optima of IT1, IT2 and IT3 were 3.5, 6.0 and 5.5 respectively. All of them could hydrolyze sucrose and raffinose but not maltose, therefore they are all beta-fructofuranosidases. The apparent Km values for sucrose and raffinose of IT3 were 7.0 and 14.5 mM, respectively. Exogenous protein BSA could activate IT3. IT3 was inhibited by metal ions--Pb2+, Zn2+, Cu2+, Hg2+ and Ag+. The sulfhydryl group inhibitor, PCMB, and serine protease inhibitor, PMSF, had no effects on IT3 activity. It might indicate that cysteine and serine did not participate directly the active site catalytic reaction of IT3.
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Affiliation(s)
- S S Lin
- Department of Agricultural Chemistry, National Taiwan University, Taipei, R.O.C
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46
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Wang AY, Juang RH, Chang CT, Sung HY. Purification and characterization of 5'-phosphodiesterase from barley rootlets. Biochem Mol Biol Int 1993; 29:1095-102. [PMID: 7687182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A phosphodiesterase was purified from barley rootlets by polyethylene glycol fractionation, calcium phosphate gel-cellulose adsorption, Sepharose CL-4B gel filtration, DEAE-Sepharose CL-6B ion exchange and preparative polyacrylamide gel electrophoresis (PAGE). The enzyme was purified by 103.6 folds and 11% of the enzyme activity was recovered. The purified enzyme was apparently homogeneous when examined on PAGE. It had a molecular weight of 100 kD, an optimum pH of 9.5, and a Km of 0.28 mM on the hydrolysis of p-nitrophenyl thymidine 5'-phosphate. SDS-PAGE revealed that the enzyme molecule might be composed of two or three subunits. Reducing agents, CuSO4, EDTA and 5'-nucleotides were inhibitory to the enzyme activity. This enzyme was able to hydrolyze RNA and denatured DNA efficiently, whereas native DNA was not a good substrate.
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Affiliation(s)
- A Y Wang
- Department of Agricultural Chemistry, National Taiwan University, Taipei
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47
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Sung HY, Yu RH, Chang CT. Purification and some properties of peroxidase isozymes from pineapple stem. Biochem Mol Biol Int 1993; 29:185-95. [PMID: 8490564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The enzyme peroxidase is widely distributed among the higher plants. Isozymes of peroxidase are known to occur in a variety of tissues in a large number of plant species. In this study, peroxidase isozymes were purified from the extract of pineapple stem through successive steps of ammonium sulfate fractionation, CM-Sepharose CL-6B chromatographies and DEAE-Sepharose CL-6B chromatographies. By these steps, twelve isozymes of peroxidase were obtained. Some properties of the isozymes were studied and compared.
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Affiliation(s)
- H Y Sung
- Department of Agricultural Chemistry, National Taiwan University, Taipei, R.O.C
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48
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Chang CT, Lo HF, Wu CJ, Sung HY. Purification and properties of chitinase from cabbage. Biochem Int 1992; 28:707-15. [PMID: 1482407] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Chitinase has been purified from the extract of cabbage through successive steps of ammonium sulfate fractionation, chromatofocusing and Sephadex G-75 gel filtration. By these steps, the purity of the enzyme increased by 93.3 fold and the recovery of the enzyme activity was 20%. The purified enzyme had an optimal pH of 5.0, an optimal temperature between 40 to 50 degrees C and a Km of 76 microM for hydrolysis of ethylene glycol chitin. The molecular weight of the enzyme determined from filtration through Sephadex G-75 was 30,000 daltons. Heavy metal ions, Hg2+ (0.5 mM) and Ag+(2.5 mM) significantly inhibited the activity of the enzyme. NBSI1 (1.0 mM), DNFB (0.5 mM) and PMSF (0.5 mM) completely inhibited the activity of the enzyme. The enzyme also showed muramidase activity for hydrolysis of Micrococcus lysodeikticus cell wall. The presence of chitinase in cabbage may function as a defense enzyme against potential pathogens.
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Affiliation(s)
- C T Chang
- Department of Food and Nutrition, Providence University, Shalu, Taiwan, R.O.C
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49
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Wang AY, Yu WP, Juang RH, Huang JW, Sung HY, Su JC. Presence of three rice sucrose synthase genes as revealed by cloning and sequencing of cDNA. Plant Mol Biol 1992; 18:1191-1194. [PMID: 1534703 DOI: 10.1007/bf00047725] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
By sequencing cDNA clones, we have concluded that three distinct sucrose genes are expressed in rice (Oryza sativa cv. Tainong 67). When the amino acid sequences deduced from these cDNAs as well as those of known sucrose synthase are compared, the highest divergence is found in the C-termini. The most suitable DNA sequences for use as specific for the mRNA derived from these genes have been suggested.
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Affiliation(s)
- A Y Wang
- Department of Agricultural Chemistry, National Taiwan University, Taipei, ROC
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50
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Affiliation(s)
- W P Yu
- Department of Agricultural Chemistry, National Taiwan University, Taipei
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