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Jao TM, Fang WH, Ciou SC, Yu SL, Hung YL, Weng WT, Lin TY, Tsai MH, Yang YC. PCDH10 exerts tumor-suppressor functions through modulation of EGFR/AKT axis in colorectal cancer. Cancer Lett 2020; 499:290-300. [PMID: 33271263 DOI: 10.1016/j.canlet.2020.11.017] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Revised: 11/12/2020] [Accepted: 11/13/2020] [Indexed: 02/07/2023]
Abstract
Protocadherin 10 (PCDH10) is identified as a tumor suppressor in multiple cancers. The molecular mechanisms that mediate the functions of PCDH10 have yet to be fully elucidated. Here, we demonstrated that ectopic expression of PCDH10 in colorectal cancer (CRC) cells induced cell cycle retardation and increased apoptosis through regulation of the p53/p21/Rb axis and Bcl-2 expression. Overexpression of PCDH10 reversed the epithelial-mesenchymal transition (EMT) process with morphological changes and EMT marker alterations. Mechanistic study revealed that PCDH10 inhibited AKT/GSK3β signaling pathway which in turn reduced β-catenin activity and thus attenuated Snail and Twist1 expression. Furthermore, PCDH10 inhibited the stemness of CRC cells, including spheroid formation and stem cell markers. A proteomics approach revealed that PCDH10 could interact with EGFR, which was further verified by co-immunoprecipitation. Moreover, restoration of PCDH10 expression reduced EGFR phosphorylation. Accordingly, our work proposes a novel pathway by which PCDH10 directly engages in the negative regulation of EGFR/AKT/β-catenin signaling pathway, resulting in tumor suppression.
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Affiliation(s)
- Tzu-Ming Jao
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan; Department of Medical Education and Research, Kaohsiung Veterans General Hospital, Kaohsiung City, 813, Taiwan
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, 100, Taiwan
| | - Shih-Ci Ciou
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan
| | - Sung-Liang Yu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, 100, Taiwan
| | - Yu-Lin Hung
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan
| | - Wei-Ting Weng
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan
| | - Tsai-Yi Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan
| | - Ming-Hong Tsai
- Department of Surgery, Cardinal Tien Hospital, New Taipei City, 231, Taiwan; School of Medicine, Fu-Jen Catholic University, New Taipei City, 242, Taiwan.
| | - Ya-Chien Yang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, 100, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, 100, Taiwan.
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2
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Chang HL, Su KY, Goodman SD, Yen RS, Cheng WC, Yang YC, Lin LI, Chang SY, Fang WH. Measurement of uracil-DNA glycosylase activity by matrix assisted laser desorption/ionization time-of-flight mass spectrometry technique. DNA Repair (Amst) 2020; 97:103028. [PMID: 33254084 DOI: 10.1016/j.dnarep.2020.103028] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 11/19/2020] [Accepted: 11/19/2020] [Indexed: 11/26/2022]
Abstract
Uracil-DNA glycosylase (UDG) is a highly conserved DNA repair enzyme that acts as a key component in the base excision repair pathway to correct hydrolytic deamination of cytosine making it critical to genome integrity in living organisms. We report here a non-labeled, non-radio-isotopic and very specific method to measure UDG activity. Oligodeoxyribonucleotide duplex containing a site-specific G:U mismatch that is hydrolyzed by UDG then subjected to Matrix Assisted Laser Desorption/Ionization time-of-flight mass spectrometry analysis. A protocol was developed to maintain the AP product in DNA without strand break then the cleavage of uracil was identified by the mass change from uracil substrate to AP product. From UDG kinetic analysis, for G:U substrate the Km is 50 nM, Vmax is 0.98 nM/s and Kcat = 9.31 s-1. The method was applied to uracil glycosylase inhibitor measurement with an IC50 value of 7.6 pM. Single-stranded and double-stranded DNAs with uracil at various positions of the substrates were also tested for UDG activity albeit with different efficiencies. The simple, rapid, quantifiable, scalable and versatile method has potential to be the reference method for monofunctional glycosylase measurement, and can also be used as a tool for glycosylase inhibitors screening.
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Affiliation(s)
- Hui-Lan Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC
| | - Kang-Yi Su
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Steven D Goodman
- Center for Microbial Pathogenesis, Nationwide Children's Hospital and the Department of Pediatrics, the Ohio State University, Columbus, OH, USA
| | - Rong-Syuan Yen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC
| | - Wern-Cherng Cheng
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Ya-Chien Yang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Liang-In Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Sui-Yuan Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, National Taiwan University College of Medicine, Taipei, Taiwan, ROC; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan, ROC.
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Su KY, Goodman SD, Lai HM, Yen RS, Hu WY, Cheng WC, Lin LI, Yang YC, Fang WH. Proofreading and DNA Repair Assay Using Single Nucleotide Extension and MALDI-TOF Mass Spectrometry Analysis. J Vis Exp 2018:57862. [PMID: 29985320 PMCID: PMC6101880 DOI: 10.3791/57862] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [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] [Indexed: 10/31/2022] Open
Abstract
The maintenance of the genome and its faithful replication is paramount for conserving genetic information. To assess high fidelity replication, we have developed a simple non-labeled and non-radio-isotopic method using a matrix-assisted laser desorption ionization with time-of-flight (MALDI-TOF) mass spectrometry (MS) analysis for a proofreading study. Here, a DNA polymerase [e.g., the Klenow fragment (KF) of Escherichia coli DNA polymerase I (pol I) in this study] in the presence of all four dideoxyribonucleotide triphosphates is used to process a mismatched primer-template duplex. The mismatched primer is then proofread/extended and subjected to MALDI-TOF MS. The products are distinguished by the mass change of the primer down to single nucleotide variations. Importantly, a proofreading can also be determined for internal single mismatches, albeit at different efficiencies. Mismatches located at 2-4-nucleotides (nt) from the 3' end were efficiently proofread by pol I, and a mismatch at 5 nt from the primer terminus showed only a partial correction. No proofreading occurred for internal mismatches located at 6 - 9 nt from the primer 3' end. This method can also be applied to DNA repair assays (e.g., assessing a base-lesion repair of substrates for the endo V repair pathway). Primers containing 3' penultimate deoxyinosine (dI) lesions could be corrected by pol I. Indeed, penultimate T-I, G-I, and A-I substrates had their last 2 dI-containing nucleotides excised by pol I before adding a correct ddN 5'-monophosphate (ddNMP) while penultimate C-I mismatches were tolerated by pol I, allowing the primer to be extended without repair, demonstrating the sensitivity and resolution of the MS assay to measure DNA repair.
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Affiliation(s)
- Kang-Yi Su
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University; Department of Laboratory Medicine, National Taiwan University Hospital
| | - Steven D Goodman
- Center for Microbial Pathogenesis, Nationwide Children's Hospital and the Department of Pediatrics, The Ohio State University
| | - Hung-Ming Lai
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University
| | - Rong-Syuan Yen
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University
| | - Wei-Yao Hu
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University
| | - Wern-Cherng Cheng
- Department of Laboratory Medicine, National Taiwan University Hospital
| | - Liang-In Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University; Department of Laboratory Medicine, National Taiwan University Hospital
| | - Ya-Chien Yang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University; Department of Laboratory Medicine, National Taiwan University Hospital
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University; Department of Laboratory Medicine, National Taiwan University Hospital;
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4
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Luo WJ, Cheng TY, Wong KI, Fang WH, Liao KM, Hsieh YT, Su KY. Novel therapeutic drug identification and gene correlation for fatty liver disease using high-content screening: Proof of concept. Eur J Pharm Sci 2018; 121:106-117. [PMID: 29800612 DOI: 10.1016/j.ejps.2018.05.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2018] [Revised: 05/13/2018] [Accepted: 05/18/2018] [Indexed: 02/06/2023]
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a problem in obese people caused by increasing intake of high-calorie food such as fructose implicated in the elevated prevalence. It is necessary to identify novel drugs to develop effective therapies. In this study, we combined LOPAC® (The Library of Pharmacologically Active Compounds) and High-Content screening to identify compounds that significantly reduced intracellular lipid droplets (LD) after high fat medium (HFM) treatment. Among 1280 compounds, we identified 239 compounds that reduced LD by >50%. Of these, 17 maintained cell viability. Nine of them were selected for validation using normal primary hepatocytes, of which five compounds showed dose-dependent efficacy. Whole genome transcriptomic network analysis was performed to construct the underlying regulatory network. There were 831 (711 up-regulated and 120 down-regulated genes) and 3480 (2009 up-regulated and 1471 down-regulated genes) genes that showed a significant change (>2-fold; p < 0.05) after 12 and 24 h HFM treatment, respectively. Gene enrichment and pathway analysis showed several immune responses mediated by MIF, IL-17, TLR, and IL-6. These compounds modulate lipogenesis via GSK3β and CREB1, which is followed by an alteration in the expression of several downstream genes related to hepatocellular carcinoma and hepatitis. CREB1 is a core transcription factor and may be a potential therapeutic target for liver disease. In conclusion, this proof of concept provides a strategy for identifying novel drugs for treatment of fatty liver disease as well as elucidates their underlying mechanisms. This research provides opportunity for developing future pharmaceutical therapeutics.
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Affiliation(s)
- Wei-Jia Luo
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Ting-Yu Cheng
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Keng-Ieng Wong
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Keng-Mao Liao
- Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan
| | - Yun-Ting Hsieh
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Kang-Yi Su
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan; Genome and Systems Biology Degree Program, National Taiwan University and Academia Sinica, Taipei, Taiwan; Center of Genomic Medicine, National Taiwan University, Taipei, Taiwan; Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan.
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5
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Chang CK, Lin XR, Lin YL, Fang WH, Lin SW, Chang SY, Kao JT. Magnolol-mediated regulation of plasma triglyceride through affecting lipoprotein lipase activity in apolipoprotein A5 knock-in mice. PLoS One 2018; 13:e0192740. [PMID: 29425239 PMCID: PMC5806881 DOI: 10.1371/journal.pone.0192740] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [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: 09/20/2017] [Accepted: 01/30/2018] [Indexed: 01/24/2023] Open
Abstract
Hyperlipidemia is a risk factor of arteriosclerosis, stroke, and other coronary heart disease, which has been shown to correlate with single nucleotide polymorphisms of genes essential for lipid metabolism, such as lipoprotein lipase (LPL) and apolipoprotein A5 (APOA5). In this study, the effect of magnolol, the main active component extracted from Magnolia officinalis, on LPL activity was investigated. A dose-dependent up-regulation of LPL activity, possibly through increasing LPL mRNA transcription, was observed in mouse 3T3-L1 pre-adipocytes cultured in the presence of magnolol for 6 days. Subsequently, a transgenic knock-in mice carrying APOA5 c.553G>T variant was established and then fed with corn oil with or without magnolol for four days. The baseline plasma triglyceride levels in transgenic knock-in mice were higher than those in wild-type mice, with the highest increase occurred in homozygous transgenic mice (106 mg/dL vs 51 mg/dL, p<0.01). After the induction of hyperglyceridemia along with the administration of magnolol, the plasma triglyceride level in heterozygous transgenic mice was significantly reduced by half. In summary, magnolol could effectively lower the plasma triglyceride levels in APOA5 c.553G>T variant carrier mice and facilitate the triglyceride metabolism in postprandial hypertriglyceridemia.
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Affiliation(s)
- Chun-Kai Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Xiu-Ru Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Laboratory Medicine, National Yang-Ming University Hospital, Yilan, Taiwan
| | - Yen-Lin Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Shu-Wha Lin
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
| | - Sui-Yuan Chang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- Department of Laboratory Medicine, National Taiwan University Hospital, Taipei, Taiwan
- * E-mail: (JK); (SC)
| | - Jau-Tsuen Kao
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan
- * E-mail: (JK); (SC)
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6
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Hsiao YY, Fang WH, Lee CC, Chen YP, Yuan HS. Structural insights into DNA repair by RNase T--an exonuclease processing 3' end of structured DNA in repair pathways. PLoS Biol 2014; 12:e1001803. [PMID: 24594808 PMCID: PMC3942315 DOI: 10.1371/journal.pbio.1001803] [Citation(s) in RCA: 21] [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] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2013] [Accepted: 01/21/2014] [Indexed: 11/19/2022] Open
Abstract
DNA repair mechanisms are essential for preservation of genome integrity. However, it is not clear how DNA are selected and processed at broken ends by exonucleases during repair pathways. Here we show that the DnaQ-like exonuclease RNase T is critical for Escherichia coli resistance to various DNA-damaging agents and UV radiation. RNase T specifically trims the 3' end of structured DNA, including bulge, bubble, and Y-structured DNA, and it can work with Endonuclease V to restore the deaminated base in an inosine-containing heteroduplex DNA. Crystal structure analyses further reveal how RNase T recognizes the bulge DNA by inserting a phenylalanine into the bulge, and as a result the 3' end of blunt-end bulge DNA can be digested by RNase T. In contrast, the homodimeric RNase T interacts with the Y-structured DNA by a different binding mode via a single protomer so that the 3' overhang of the Y-structured DNA can be trimmed closely to the duplex region. Our data suggest that RNase T likely processes bulge and bubble DNA in the Endonuclease V-dependent DNA repair, whereas it processes Y-structured DNA in UV-induced and various other DNA repair pathways. This study thus provides mechanistic insights for RNase T and thousands of DnaQ-like exonucleases in DNA 3'-end processing.
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Affiliation(s)
- Yu-Yuan Hsiao
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
- Department of Biological Science and Technology, National Chiao Tung University, Hsinchu, Taiwan, Republic of China
| | - Woei-Horng Fang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Chia-Chia Lee
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
| | - Yi-Ping Chen
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
| | - Hanna S. Yuan
- Institute of Molecular Biology, Academia Sinica, Taipei, Taiwan, Republic of China
- Graduate Institute of Biochemistry and Molecular Biology, National Taiwan University, Taipei, Taiwan, Republic of China
- * E-mail:
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7
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Lee CC, Yang YC, Goodman SD, Lin CJ, Chen YA, Wang YT, Cheng WC, Lin LI, Fang WH. The excision of 3' penultimate errors by DNA polymerase I and its role in endonuclease V-mediated DNA repair. DNA Repair (Amst) 2013; 12:899-911. [PMID: 24012058 DOI: 10.1016/j.dnarep.2013.08.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 11/28/2022]
Abstract
Deamination of adenine can occur spontaneously under physiological conditions, and is enhanced by exposure of DNA to ionizing radiation, UV light, nitrous acid, or heat, generating the highly mutagenic lesion of deoxyinosine in DNA. Such DNA lesions tends to generate A:T to G:C transition mutations if unrepaired. In Escherichia coli, deoxyinosine is primarily removed through a repair pathway initiated by endonuclease V (endo V). In this study, we compared the repair of three mutagenic deoxyinosine lesions of A-I, G-I, and T-I using E. coli cell-free extracts as well as reconstituted protein system. We found that 3'-5' exonuclease activity of DNA polymerase I (pol I) was very important for processing all deoxyinosine lesions. To understand the nature of pol I in removing damaged nucleotides, we systemically analyzed its proofreading to 12 possible mismatches 3'-penultimate of a nick, a configuration that represents a repair intermediate generated by endo V. The results showed all mismatches as well as deoxyinosine at the 3' penultimate site were corrected with similar efficiency. This study strongly supports for the idea that the 3'-5' exonuclease activity of E. coli pol I is the primary exonuclease activity for removing 3'-penultimate deoxyinosines derived from endo V nicking reaction.
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Affiliation(s)
- Chia-Chia Lee
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, 100-02, Taiwan, ROC
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8
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Tsai MH, Fang WH, Lin SH, Tzeng ST, Huang CS, Yen SJ, Chou SJ, Yang YC. Mapping of Genetic Deletions on Chromosome 3 in Colorectal Cancer: Loss of 3p25-pter is Associated with Distant Metastasis and Poor Survival. Ann Surg Oncol 2011; 18:2662-70. [DOI: 10.1245/s10434-011-1603-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2010] [Indexed: 11/18/2022]
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Huang CP, Au LC, Chiou RYY, Chung PC, Chen SY, Tang WC, Chang CL, Fang WH, Lin SB. Arachidin-1, a peanut stilbenoid, induces programmed cell death in human leukemia HL-60 cells. J Agric Food Chem 2010; 58:12123-12129. [PMID: 21067217 DOI: 10.1021/jf102993j] [Citation(s) in RCA: 30] [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] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The stilbenoids, arachidin-1 (Ara-1), arachidin-3, isopentadienylresveratrol, and resveratrol, have been isolated from germinating peanut kernels and characterized as antioxidant and anti-inflammatory agents. Resveratrol possesses anticancer activity, and studies have indicated that it induces programmed cell death (PCD) in human leukemia HL-60 cells. In this study, the anticancer activity of these stilbenoids was determined in HL-60 cells. Ara-1 had the highest efficacy in inducing PCD in HL-60 cells, with an approximately 4-fold lower EC50 than resveratrol. Ara-1 treatment caused mitochondrial membrane damage, activation of caspases, and nuclear translocation of apoptosis-inducing factor, resulting in chromosome degradation and cell death. Therefore, Ara-1 induces PCD in HL-60 cells through caspase-dependent and caspase-independent pathways. Ara-1 demonstrates its efficacy as an anticancer agent by inducing caspase-independent cell death, which is an alternative death pathway of cancer cells with mutations in key apoptotic genes. These findings indicate the merits of screening other peanut stilbenoids for anticancer activity.
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Affiliation(s)
- Cheng-Po Huang
- Department of Clinical Laboratory Sciences and Medical Biotechnology, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
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10
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Tsai MH, Fang WH, Lin SW, Yen SJ, Chou SJ, Yang YC. Mitochondrial genomic instability in colorectal cancer: no correlation to nuclear microsatellite instability and allelic deletion of hMSH2, hMLH1, and p53 genes, but prediction of better survival for Dukes' stage C disease. Ann Surg Oncol 2009; 16:2918-25. [PMID: 19582509 DOI: 10.1245/s10434-009-0581-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2009] [Revised: 06/01/2009] [Accepted: 06/01/2009] [Indexed: 01/10/2023]
Abstract
PURPOSE Malfunction of mismatch repair (MMR) system and p53 produces nuclear genomic instability and is involved in colorectal tumorigenesis. In addition to a nuclear genome, eukaryotic cells have cytoplasmic genomes that are compartmentalized in the mitochondria. The aims of this study were to detect the mitochondrial genomic instability (mtGI) in colorectal carcinomas, and to explore its relationship with nuclear genetic alterations and its prognostic meaning. METHODS Eighty-three colorectal carcinomas with corresponding normal mucosa were analyzed for mtGI, nuclear microsatellite instability (nMSI), and loss of heterozygosity (LOH) of hMSH2, hMLH1, and p53 genes. Mitochondrial and nuclear alterations were examined for mutual correlation and for associations with clinicopathological features and clinical outcomes. RESULTS Out of 83 cases, mtGI was identified in 23 carcinomas (27.7%), whereas nMSI was detected in 11 (13.3%). Of the 23 cases with mtGI, only two showed nMSI simultaneously. The frequencies of LOH of hMSH2, hMLH1, and p53 were 16.1%, 11.6%, and 65.3%, respectively. There was no significant association between mtGI and these allelic losses. Notably, Dukes' C patients with mtGI had better disease-free and overall survival than those lacking this feature (p = 0.0516 and 0.0313, respectively). CONCLUSIONS Mitochondrial genomic instability occurs with a high frequency in colorectal carcinomas but is independent of nMSI and allelic deletion of hMSH2, hMLH1, and p53 genes. The results suggest that, instead of nuclear MMR system, there might be different mechanisms involving mitochondrial genomic integrity, and mtGI confers a better prognosis in Dukes' C colorectal cancer.
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Affiliation(s)
- Ming-Hong Tsai
- School of Medicine, Fu-Jen Catholic University, Taipei, Taiwan
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11
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Fang WH, Hu LL, Yang XL, Hu K, Liang SC, Zhou S. Effect of temperature on pharmacokinetics of enrofloxacin in mud crab, Scylla serrata (Forsskål), following oral administration. J Fish Dis 2008; 31:171-176. [PMID: 18261030 DOI: 10.1111/j.1365-2761.2007.00884.x] [Citation(s) in RCA: 5] [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: 05/25/2023]
Abstract
The study was conducted to evaluate the pharmacokinetics of enrofloxacin following a single oral gavage (10 mg kg(-1)) in mud crab, Scylla serrata, at water temperatures of 19 and 26 degrees C. Enrofloxacin concentration in haemolymph was determined using high-performance liquid chromatography (HPLC). A multiple and repeated haemolymph sampling from the articular cavity of crab periopods was developed. The haemolymph of an individual crab was successfully sampled up to 11 times from the articular cavity. The profile of haemolymph enrofloxacin concentration of an individual crab versus time was thus achieved. The mean haemolymph enrofloxacin concentration versus time was described by a two-compartment model with first-order absorption at two water temperatures. The peak concentrations of haemolymph enrofloxacin at 19 and 26 degrees C were 7.26 and 11.03 mug mL(-1), at 6 and 2 h, respectively. The absorption and distribution half-life time ( and t(1/2alpha)) at 19 degrees C were 3.7 and 4.5 h, respectively, which were markedly larger than the corresponding values (1.1 and 1.5 h) at 26 degrees C; the elimination half-life time (t(1/2beta)) was 79.1 and 56.5 h at 19 and 26 degrees C, respectively. The area under curve (AUC), total body clearance (Cl) and mean residence time (MRT(0-infinity)) at 19 degrees C were 636.0 mg L(-1) h, 0.016 L h(-1) kg(-1) and 102.5 h, respectively; the corresponding values at 26 degrees C were 583.4 mg L(-1) h, 0.018 L h(-1) kg(-1)and 63.7 h. These results indicate that enrofloxacin is absorbed and eliminated more rapidly in mud crab at 26 degrees C than at 19 degrees C.
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Affiliation(s)
- W H Fang
- East China Sea Fisheries Research Institute, Chinese Academy of Fisheries Science, Key and Open Laboratory of Marine and Estuarine Fisheries, Ministry of Agriculture, 300 Jungong Road, Shanghai, China.
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12
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Huang CP, Fang WH, Lin LI, Chiou RY, Kan LS, Chi NH, Chen YR, Lin TY, Lin SB. Anticancer activity of botanical alkyl hydroquinones attributed to topoisomerase II poisoning. Toxicol Appl Pharmacol 2008; 227:331-8. [DOI: 10.1016/j.taap.2007.11.014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2007] [Revised: 11/12/2007] [Accepted: 11/14/2007] [Indexed: 10/22/2022]
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Chien KL, Fang WH, Wen HC, Lin HP, Lin YL, Lin SW, Wu JH, Kao JT. APOA1/C3/A5 haplotype and risk of hypertriglyceridemia in Taiwanese. Clin Chim Acta 2007; 390:56-62. [PMID: 18206649 DOI: 10.1016/j.cca.2007.12.014] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2007] [Revised: 12/19/2007] [Accepted: 12/19/2007] [Indexed: 11/17/2022]
Abstract
BACKGROUND Apolipoprotein A5 gene (APOA5) has been shown to modulate plasma triglyceride concentrations. We investigated 2 distinct APOA1/C3/A5 haplotypes roles for hypertriglyceridemia. METHODS We recruited 308 cases of hypertriglyceridemia and 281 normal controls from a hospital. Twelve single nucleotide polymorphisms (SNPs) across the APOA1/C3/A5 gene region were genotyped. RESULTS One haplotype containing the minor alleles of the APOA5 (-1131T>C, c.553G>T) and APOA1 (-3013C>T,-75G>A) was more prevalent in cases than in controls (11.3% vs. 1.1%, respectively) and was statistically significantly associated with high triglycerides (adjusted odds ratio: 12.83, 95% confidence interval [CI]: 5.1-32.4, P<0.001). Another haplotype that was associated with hypertriglyceridemia (adjusted odds ratio 2.13, 95% CI, 1.37-3.29, P=0.001). Participants carrying both minor alleles of APOA5-1131CC and c.553TT had a 116% higher triglyceride concentration compared with those carrying common allele. CONCLUSIONS The APOA1/C3/A5 haplotype represents an important locus for predicting risk of hypertriglyceridemia among Taiwanese.
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Affiliation(s)
- Kuo-Liong Chien
- Institute of Preventive Medicine, College of Public School, National Taiwan University, Taiwan
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Li CH, Chen PY, Chang UM, Kan LS, Fang WH, Tsai KS, Lin SB. Ganoderic acid X, a lanostanoid triterpene, inhibits topoisomerases and induces apoptosis of cancer cells. Life Sci 2005; 77:252-65. [PMID: 15878354 DOI: 10.1016/j.lfs.2004.09.045] [Citation(s) in RCA: 86] [Impact Index Per Article: 4.5] [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: 05/10/2004] [Accepted: 09/28/2004] [Indexed: 10/25/2022]
Abstract
Lanostanoid triterpenes isolated from Ganoderma amboinense were found to inhibit the growth of numerous cancer cell lines, and some of them inhibited the activities of topoisomerases I and IIalpha in vitro. Among the bioactive isolates, one of the most potent triterpene was identified to be 3 alpha-hydroxy-15 alpha-acetoxy-lanosta-7,9(11),24-trien-26-oic acid, ganoderic acid X (GAX). Treatment of human hepatoma HuH-7 cells with GAX caused immediate inhibition of DNA synthesis as well as activation of ERK and JNK mitogen-activated protein kinases, and cell apoptosis. Molecular events of apoptosis including degradation of chromosomal DNA, decrease in the level of Bcl-xL, the disruption of mitochondrial membrane, cytosolic release of cytochrome c and activation of caspase-3 were elucidated. The ability of GAX to inhibit topoisomerases and to sensitize the cancer cells toward apoptosis fulfills the feature of a potential anticancer drug.
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Affiliation(s)
- Chyi-Hann Li
- Graduate Institute of Medical Technology, College of Medicine, National Taiwan University, Taipei, Taiwan, ROC
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15
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Phillips DL, Fang WH. Density functional theory investigation of the reactions of isodihalomethanes (CH(2)X-X where X = Cl, Br, or I) with ethylene: substituent effects on the carbenoid behavior of the CH(2)X-X species. J Org Chem 2001; 66:5890-6. [PMID: 11511267 DOI: 10.1021/jo010582i] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We investigated the chemical reactions of isodihalomethane (CH(2)X-X) and CH(2)X radical species (where X = Cl, Br, or I) with ethylene and the isomerization reactions of CH(2)X-X using density functional theory calculations. The CH(2)X-X species readily reacts with ethylene to give the cyclopropane product and an X(2) product via a one-step reaction with barrier heights of approximately 2.9 kcal/mol for CH(2)I-I, 6.8 kcal/mol for CH(2)Br-Br, and 8.9 kcal/mol for CH(2)Cl-Cl. The CH(2)X reactions with ethylene proceed via a two-step reaction mechanism to give a cyclopropane product and X atom product with much larger barriers to reaction. This suggests that photocyclopropanation reactions using ultraviolet excitation of dihalomethanes most likely occurs via the isodihalomethane species and not the CH(2)X species. The isomerization reactions of CH(2)X-X had barrier heights of approximately 14.4 kcal/mol for CH(2)I-I, 11.8 kcal/mol for CH(2)Br-Br, and 9.1 kcal/mol for CH(2)Cl-Cl. We compare our results for the CH(2)X-X carbenoids to results from previous calculations of the Simmons-Smith-type carbenoids (XCH(2)ZnX) and Li-type carbenoids (LiCH(2)X) and discuss their differences and similarities as methylene transfer agents.
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Affiliation(s)
- D L Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, PR China.
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16
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Fang WH, Yao YM, Shi ZG, Yu Y, Wu Y, Lu LR, Sheng ZY. Effect of recombinant bactericidal/permeability-increasing protein on endotoxin translocation and lipopolysaccharide-binding protein/CD14 expression in rats after thermal injury. Crit Care Med 2001; 29:1452-9. [PMID: 11445707 DOI: 10.1097/00003246-200107000-00025] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [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: 12/13/2022]
Abstract
OBJECTIVE To investigate the potential mechanisms underlying the in vivo effect of recombinant bactericidal/permeability-increasing protein (rBPI21) on endogenous bacteria or endotoxin translocation and lipopolysaccharide-binding protein/CD14 expression secondary to thermal injury. DESIGN Prospective, randomized, controlled animal study. SETTING College hospital animal research laboratory. SUBJECTS Thirty-six male Wistar rats weighing 250-300 g. INTERVENTIONS The rats were anesthetized, and a 35% total body surface area full-thickness burn was created. Animals were randomized to receive treatment with either rBPI21 or the control protein (albumin). rBPI21 (2 mg/kg body wt, BPI group) or a protein control preparation (burn group) in the same dose was administered in an intravenous bolus at 30 mins and 4 hrs after thermal injury. All animals were killed at 12 and 24 hrs postburn (six to ten rats for each interval). In addition, eight rats were taken as normal controls. MEASUREMENT AND MAIN RESULTS Our data showed that treatment with rBPI21 was effective in preventing endotoxin translocation secondary to severe burns. Meanwhile, tissue lipopolysaccharide-binding protein, CD14, and tumor necrosis factor-alpha mRNA expression in various organs were inhibited markedly by rBPI21 secondary to acute insults (p <.05-.01). Furthermore, significant reduction in serum aminoleucine transferase concentrations and elevation in intestinal diamine oxidase activities in the rBPI21-treated group were found compared with controls (p <.05-.01). CONCLUSIONS These findings indicate that endotoxin accumulated in local sites after thermal injury can markedly up-regulate lipopolysaccharide-binding protein/CD14 and tumor necrosis factor-alpha mRNA expression in various organs. Meanwhile, up-regulation of lipopolysaccharide-binding protein/CD14 expression would be the major molecular mechanism of increasing sensitivity to endogenous endotoxin response after burns. Early treatment with rBPI21may be effective in attenuating multiple organ damage resulting from gut-origin endotoxin translocation. This might be associated with the down-regulation effects of tissue lipopolysaccharide-binding protein and CD14 gene expression by the use of rBPI21.
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Affiliation(s)
- W H Fang
- Department of Microbiology and Immunology, Trauma Research Center, Postgraduate Medical College, 304th Hospital, Beijing, People's Republic of China
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17
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Phillips DL, Fang WH, Zheng X. Isodiiodomethane is the methylene transfer agent in cyclopropanation reactions with olefins using ultraviolet photolysis of diiodomethane in solutions: a density functional theory investigation of the reactions of isodiiodomethane, iodomethyl radical, and iodomethyl cation with ethylene. J Am Chem Soc 2001; 123:4197-203. [PMID: 11457184 DOI: 10.1021/ja003090g] [Citation(s) in RCA: 49] [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] [Indexed: 11/30/2022]
Abstract
We examine the chemical reactions of the isodiiodomethane (CH2I-I), .CH2I and CH2I(+) species with ethylene using density functional theory computations. The CH2I-I species readily reacts with ethylene to give the cyclopropane product and an I2 product via a one-step reaction with a barrier height of approximately 2.9 kcal/mol. However, the.CH2I and CH2I(+) species have much more difficult pathways (with larger potential barriers) to react with ethylene via a two-step reaction mechanism. Comparison of experimental results to our present calculation results indicates that the CH2I-I photoproduct species is most likely the methylene transfer agent for the cyclopropanation reaction of olefins via ultraviolet photoexcitation of diiodomethane.
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Affiliation(s)
- D L Phillips
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong S. A. R., P. R. China
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18
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Fang WH, Yao YM, Shi ZG. [Myeloid defensins: an update review]. Sheng Li Ke Xue Jin Zhan 2001; 32:153-6. [PMID: 12545889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
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19
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Affiliation(s)
- J J Tsai-Wu
- Department of Clinical Research, National Taiwan University Hospital, Taipei, Republic of China
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20
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Littman SJ, Fang WH, Modrich P. Repair of large insertion/deletion heterologies in human nuclear extracts is directed by a 5' single-strand break and is independent of the mismatch repair system. J Biol Chem 1999; 274:7474-81. [PMID: 10066813 DOI: 10.1074/jbc.274.11.7474] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [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
The repair of 12-, 27-, 62-, and 216-nucleotide unpaired insertion/deletion heterologies has been demonstrated in nuclear extracts of human cells. When present in covalently closed circular heteroduplexes or heteroduplexes containing a single-strand break 3' to the heterology, such structures are subject to a low level repair reaction that occurs with little strand bias. However, the presence of a single-strand break 5' to the insertion/deletion heterology greatly increases the efficiency of rectification and directs repair to the incised DNA strand. Because nick direction of repair is independent of the strand in which a particular heterology is placed, the observed strand bias is not due to asymmetry imposed on the heteroduplex by the extrahelical DNA segment. Strand-specific repair by this system requires ATP and the four dNTPs and is inhibited by aphidicolin. Repair is independent of the mismatch repair proteins MSH2, MSH6, MLH1, and PMS2 and occurs by a mechanism that is distinct from that of the conventional mismatch repair system. Large heterology repair in nuclear extracts of human cells is also independent of the XPF gene product, and extracts of Chinese hamster ovary cells deficient in the ERCC1 and ERCC4 gene products also support the reaction.
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Affiliation(s)
- S J Littman
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, USA
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21
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Zhu DM, Fang WH, Narla RK, Uckun FM. A requirement for protein kinase C inhibition for calcium-triggered apoptosis in acute lymphoblastic leukemia cells. Clin Cancer Res 1999; 5:355-60. [PMID: 10037185] [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: 02/10/2023]
Abstract
We have evaluated the cytotoxicities of the combinations of calcium mobilizers and PKC inhibitors against human acute lymphoblastic leukemia (ALL) cells. Here we report that calcium mobilizers alone or PKC inhibitors alone do not induce apoptosis in human ALL cells. However, the combinations of calcium mobilizers with potent inhibitors of PKC cause significant apoptosis in ALL cells. Our results provide experimental evidence that PKC blocks Ca2+-triggered apoptosis in human ALL cells. Thus, PKC inhibitors can be used to enhance the antileukemic activity of chemical or biological agents that trigger an apoptotic calcium signal in ALL cells. The exquisite sensitivity of ALL cells to calcium-dependent apoptosis in the presence of PKC inhibitors could provide the basis for new treatment programs against ALL.
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Affiliation(s)
- D M Zhu
- Department of Immunology, Hughes Institute, St. Paul, Minnesota 55113, USA
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22
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Zhu DM, Narla RK, Fang WH, Chia NC, Uckun FM. Calphostin C triggers calcium-dependent apoptosis in human acute lymphoblastic leukemia cells. Clin Cancer Res 1998; 4:2967-76. [PMID: 9865907] [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: 02/09/2023]
Abstract
Recent studies have demonstrated that the naturally occurring perylenequinone antibiotic calphostin C is a potent inhibitor of protein kinase C and can induce apoptosis in some tumor cell lines by an as yet unknown mechanism. Here we demonstrate that calphostin C induces dose-dependent apoptosis in DT40 chicken lymphoma B-cells, and targeted disruption of lyn, syk, btk, PLCgamma2, or IP3R genes does not prevent or attenuate its cytotoxicity. In our study, calphostin C also induced rapid apoptosis in human acute lymphoblastic leukemia (ALL) cell lines ALL-1 (BCR-ABL+ pre-pre-B ALL), RS4;11 (MLL-AF4+ pro-B ALL), NALM-6 (pre-B ALL), DAUDI (Burkitt's/B-cell ALL), MOLT-3 (T-ALL), and JURKAT (T-ALL), whereas other potent PKC inhibitors did not. In biochemical studies, calphostin C was discovered to induce rapid calcium mobilization from intracellular stores of ALL cell lines, and its cytotoxicity against ALL cell lines was well correlated with the magnitude of this calcium signal. Calphostin C-induced apoptosis was markedly suppressed by BAPTA/AM, a cell-permeable Ca2+ chelator as well as NiCl2, an inhibitor of Ca2+/Mg2+-dependent endonucleases. Inhibition of the Ca2+/calmodulin-dependent phosphatase calcineurin with perfluoreperazine dimadeate (a calmodulin antagonist) or cyclosporin A (a specific inhibitor of calcineurin) also reduced the magnitude of calphostin C-induced apoptosis in ALL cell lines. Calphostin C was capable of inducing calcium mobilization and apoptosis in freshly obtained primary leukemic cells from children with ALL. Taken together, our results provide unprecedented evidence that calphostin C triggers a Ca2+-dependent apoptotic signal in human ALL cells.
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Affiliation(s)
- D M Zhu
- Department of Immunology, Parker Hughes Cancer Center, Roseville, Minnesota 55113, USA
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Shirabe S, Fang WH, Schwartz JP. Altered intermediate filament expression in human neuroblastoma cells transformed by a growth-promoting agent derived from schizophrenic CSF. Cell Mol Neurobiol 1997; 17:1-11. [PMID: 9118201 DOI: 10.1023/a:1026320919282] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [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: 02/04/2023]
Abstract
1. Transformed (TR) cell lines showed faster doubling times and higher cell densities at confluence, as well as altered morphology, changing from flat epitheloid to smaller round or bipolar shapes. Since such morphological changes are suggestive of alterations in intermediate filaments, we have analyzed the expression of both vimentin and neurofilament. 2. Immunohistochemical analysis of vimentin showed a redistribution from a cytoplasmic network to a perinuclear accumulation in TR cell lines. 3. Western blot analysis demonstrated that the vimentin content was decreased 60-90%. The content of the 70-kD neurofilament protein was also decreased in TR cells, but its intracellular distribution was indistinguishable from that in the control cell lines.
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Affiliation(s)
- S Shirabe
- Molecular Genetics Section, Clinical Neuroscience Branch, National Institute of Neurological Disorders and Stroke, NIH, Bethesda, Maryland 20892, USA
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24
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Parsons R, Li GM, Longley MJ, Fang WH, Papadopoulos N, Jen J, de la Chapelle A, Kinzler KW, Vogelstein B, Modrich P. Hypermutability and mismatch repair deficiency in RER+ tumor cells. Cell 1993; 75:1227-36. [PMID: 8261516 DOI: 10.1016/0092-8674(93)90331-j] [Citation(s) in RCA: 718] [Impact Index Per Article: 23.2] [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: 01/29/2023]
Abstract
A subset of sporadic colorectal tumors and most tumors developing in hereditary nonpolyposis colorectal cancer patients display frequent alterations in microsatellite sequences. Such tumors have been thought to manifest replication errors (RER+), but the basis for the alterations has remained conjectural. We demonstrate that the mutation rate of (CA)n repeats in RER+ tumor cells is at least 100-fold that in RER- tumor cells and show by in vitro assay that increased mutability of RER+ cells is associated with a profound defect in strand-specific mismatch repair. This deficiency was observed with microsatellite heteroduplexes as well as with heteroduplexes containing single base-base mismatches and affected an early step in the repair pathway. Thus, a true mutator phenotype exists in a subset of tumor cells, the responsible defect is likely to cause transitions and transversions in addition to microsatellite alterations, and a biochemical basis for this phenotype has been identified.
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Affiliation(s)
- R Parsons
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710
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Kat A, Thilly WG, Fang WH, Longley MJ, Li GM, Modrich P. An alkylation-tolerant, mutator human cell line is deficient in strand-specific mismatch repair. Proc Natl Acad Sci U S A 1993; 90:6424-8. [PMID: 8341649 PMCID: PMC46944 DOI: 10.1073/pnas.90.14.6424] [Citation(s) in RCA: 324] [Impact Index Per Article: 10.5] [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: 01/30/2023] Open
Abstract
The human lymphoblastoid MT1 B-cell line was previously isolated as one of a series of mutant cells able to survive the cytotoxic effects of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). MT1 cells nevertheless remain sensitive to mutagenesis by MNNG and display a mutator phenotype. These phenotypes have been attributed to a single genetic alteration postulated to confer a defect in strand-specific mismatch repair, a proposal that attributes the cytotoxic effect of DNA alkylation in wild-type cells to futile attempts to correct mispairs that arise during replication of alkylated template strands. Our results support this view. MNNG-induced mutations in the HPRT gene of MT1 cells are almost exclusively G.C-->A.T transitions, while spontaneous mutations observed in this mutator cell line are single-nucleotide insertions, transversions, and A.T-->G.C transitions. In vitro assay has demonstrated that the MT1 line is in fact deficient in strand-specific correction of all eight base-base mispairs. This defect, which is manifest at or prior to the excision stage of the reaction, is due to simple deficiency of a required activity because MT1 nuclear extracts can be complemented by a partially purified HeLa fraction to restore in vitro repair. These findings substantiate the idea that strand-specific mismatch repair contributes to alkylation-induced cytotoxicity and imply that this process serves as a barrier to spontaneous transition, transversion, and insertion/deletion mutations in mammalian cells.
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Affiliation(s)
- A Kat
- Division of Toxicology, Massachusetts Institute of Technology, Cambridge 02139
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26
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Fang WH, Modrich P. Human strand-specific mismatch repair occurs by a bidirectional mechanism similar to that of the bacterial reaction. J Biol Chem 1993; 268:11838-44. [PMID: 8505312] [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] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Nuclear extracts prepared from a HeLa cell line have been previously shown to support strand-specific repair of heteroduplex DNAs containing a site-specific, strand-specific incision (Holmes, J.J., Clark, S., and Modrich, P. (1990) Proc. Natl. Acad. Sci. U.S.A. 87, 5837-5841; Thomas, D.C., Roberts, J.D., and Kunkel, T.A. (1991) J. Biol. Chem. 266, 3744-3751). Further analysis of the substrate specificity of the reaction has shown that in addition to G-T, A-C, G-G, and C-C, nuclear extracts also recognize and correct in a strand-specific manner A-A, A-G, T-T, and C-T mismatches, with repair in each case being inhibited by aphidicolin. The rate of repair of a circular G-T heteroduplex was found to decrease monotonically with increasing separation between the mismatch and the strand break that targets repair, as viewed along the shorter path joining the two sites in the circular substrate. This decrease is independent of the polarity of the incised strand, suggesting that the human pathway of mismatch correction may possess a bidirectional excision capability similar to that of the Escherichia coli methyl-directed system. This possibility was confirmed by analysis of excision tracts associated with the reaction. Inhibition of DNA synthesis by aphidicolin or by omission of exogenous dNTPs leads to the mismatch-provoked formation of a single-strand gap that spans the shorter path between the strand break and the mismatch, irrespective of the polarity of the incised strand. Formation of these gaps, which extend from the site of the strand break to terminate at a number of discrete sites in the region 90 to 170 nucleotides beyond the mismatch, is therefore independent of the relative orientation of the two sites. Based on similar mismatch specificities and common features of mechanism, we have concluded that the human strand-specific mismatch repair system is functionally homologous to the bacterial methyl-directed pathway.
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Affiliation(s)
- W H Fang
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710
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Fang WH. [Clinical analysis of 76 cases of persistent ventricular tachycardia]. Zhonghua Xin Xue Guan Bing Za Zhi 1993; 21:38. [PMID: 8223154] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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28
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Fang WH, Li GM, Longley M, Holmes J, Thilly W, Modrich P. Mismatch repair and genetic stability in human cells. Cold Spring Harb Symp Quant Biol 1993; 58:597-603. [PMID: 7956074 DOI: 10.1101/sqb.1993.058.01.066] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- W H Fang
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710
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29
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Fang WH. [A preliminary report on the antiarrhythmic effect of ethmozine]. Zhonghua Xin Xue Guan Bing Za Zhi 1988; 16:154-5. [PMID: 3065022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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30
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Lu FJ, Fang WH, Chen HY, Wang MY. [Preliminary analysis of serum lactate dehydrogenase isoenzymes in patients of blackfoot disease]. Taiwan Yi Xue Hui Za Zhi 1984; 83:1001-1005. [PMID: 6597260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
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31
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Fang WH. [Some problems in the diagnosis of hypertrophic cardiomyopathy--with an analysis of 44 cardioangiographically proven cases]. Zhonghua Nei Ke Za Zhi 1982; 21:596-9. [PMID: 6217958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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32
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Fang WH. [Aprindine for intractable dysarrhythmia (author's transl)]. Zhonghua Xin Xue Guan Bing Za Zhi 1980; 8:210-2. [PMID: 7307950] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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33
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Fang WH, Hu ZX, Wang SH, Li JR, Liu YS. [Evaluation of the effects of propranolol on hypertrophic cardiomyopathy by non-invasive technics]. Zhonghua Xin Xue Guan Bing Za Zhi 1980; 8:13-5. [PMID: 7192621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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