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Chen LY, Tang RS, Wu YC, Lai CH, Chuang TH. Regiodivergent Synthesis of Methylene and Methyl Ring-Fused Isoquinolinones: Base-Promoted Isomerization of N-Allyl Amides. J Org Chem 2022; 87:5925-5937. [PMID: 35404617 DOI: 10.1021/acs.joc.2c00204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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
Methylene and methyl tricyclic isoquinolinones were selectively prepared using a palladium(II)-catalyzed aerobic aza-Wacker reaction, followed by a base- and temperature-controlled Heck reaction catalyzed by palladium(0). Exo- to endo-double-bond migration in isoquinolinones was achieved with 93-99% yields by treatment of the Heck products with Cs2CO3 in dimethyl sulfoxide (DMSO) at 150 °C. A probable mechanism for Cs2CO3-promoted olefin isomerization was proposed and examined using D-isotope labeling experiments. Finally, yuanamide, a 13-methyl-8-oxoprotoberberine alkaloid, was synthesized using the palladium-catalyzed aza-Wacker/Heck/migration sequence.
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Affiliation(s)
- Li-Yuan Chen
- School of Pharmacy, China Medical University, Taichung 406040, Taiwan
| | - Rong-Shiow Tang
- School of Pharmacy, China Medical University, Taichung 406040, Taiwan
| | - Yang-Chang Wu
- Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung 404394, Taiwan
| | - Chin-Hung Lai
- Department of Medical Applied Chemistry, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung 406040, Taiwan
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2
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Su YH, Hsu TW, Chen HA, Su CM, Huang MT, Chuang TH, Leo Su J, Hsieh CL, Chiu CF. ERK-mediated transcriptional activation of Dicer is involved in gemcitabine resistance of pancreatic cancer. J Cell Physiol 2021; 236:4420-4434. [PMID: 33184874 DOI: 10.1002/jcp.30159] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [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: 04/30/2020] [Revised: 10/29/2020] [Accepted: 11/02/2020] [Indexed: 12/12/2022]
Abstract
Gemcitabine has been a commonly used therapeutic agent for treatment of pancreatic cancer. In the clinic, a growing resistance to gemcitabine has been observed in patients with pancreatic cancer, and investigation of the underlying mechanism of gemcitabine resistance is urgently required. The microRNA (miRNA)-producing enzyme, Dicer, is crucial for the maturation of miRNAs, and is involved in clinical aggressiveness, poor prognosis, and survival outcomes in various cancers, however, the role of Dicer in acquired gemcitabine resistance of pancreatic cancer is still not clear. Here, we found that Dicer expression was significantly increased in gemcitabine-resistant PANC-1 (PANC-1/GEM) cells compared with parental PANC-1 cells and observed a high level of Dicer correlated with increased risk of pancreatic cancer. Suppression of Dicer obviously decreased gemcitabine resistance in PANC-1/GEM cells; consistently, overexpression of Dicer in PANC-1 cells increased gemcitabine resistance. Moreover, we identified that transcriptional factor Sp1 targeted the promoter region of Dicer and found ERK/Sp1 signaling regulated Dicer expression in PANC-1/GEM cells, as well as positively correlated with pancreatic cancer progression and suggest that targeting the ERK/Sp1/Dicer pathway has potential therapeutic value for pancreatic cancer with acquired resistance to gemcitabine.
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MESH Headings
- Animals
- Antimetabolites, Antineoplastic/pharmacology
- Carcinoma, Pancreatic Ductal/drug therapy
- Carcinoma, Pancreatic Ductal/enzymology
- Carcinoma, Pancreatic Ductal/genetics
- Carcinoma, Pancreatic Ductal/pathology
- Cell Line, Tumor
- DEAD-box RNA Helicases/genetics
- DEAD-box RNA Helicases/metabolism
- Deoxycytidine/analogs & derivatives
- Deoxycytidine/pharmacology
- Drug Resistance, Neoplasm/genetics
- Extracellular Signal-Regulated MAP Kinases/metabolism
- Gene Expression Regulation, Neoplastic
- Humans
- Male
- Mice, Inbred NOD
- Mice, SCID
- Pancreatic Neoplasms/drug therapy
- Pancreatic Neoplasms/enzymology
- Pancreatic Neoplasms/genetics
- Pancreatic Neoplasms/pathology
- Ribonuclease III/genetics
- Ribonuclease III/metabolism
- Signal Transduction
- Sp1 Transcription Factor/genetics
- Sp1 Transcription Factor/metabolism
- Transcriptional Activation
- Xenograft Model Antitumor Assays
- Gemcitabine
- Mice
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Affiliation(s)
- Yen-Hao Su
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Surgery, Division of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Department of General Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Tung-Wei Hsu
- Department of Surgery, Division of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Hsin-An Chen
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Surgery, Division of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Department of General Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Chih-Ming Su
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Surgery, Division of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Department of General Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ming-Te Huang
- Graduate Institute of Clinical Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- Department of Surgery, Division of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
- Department of General Surgery, School of Medicine, College of Medicine, Taipei Medical University, Taipei, Taiwan
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung, Taiwan
| | - J Leo Su
- Department of Surgery, Division of General Surgery, Shuang Ho Hospital, Taipei Medical University, New Taipei City, Taiwan
| | - Chia-Ling Hsieh
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
- The Ph.D. Program for Translational Medicine, College of Medical Science and Technology, Taipei Medical University, Taipei, Taiwan
| | - Ching-Feng Chiu
- TMU Research Center of Cancer Translational Medicine, Taipei Medical University, Taipei, Taiwan
- Nutrition Research Center, Taipei Medical University Hospital, Taipei, Taiwan
- Graduate Institute of Metabolism and Obesity Sciences, College of Nutrition, Taipei Medical University, Taipei, Taiwan
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3
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Tang RS, Chen LY, Lai CH, Chuang TH. Palladium-Catalyzed Stereoselective Aza-Wacker-Heck Cyclization: One-Pot Stepwise Strategy toward Tetracyclic Fused Heterocycles. Org Lett 2020; 22:9337-9341. [PMID: 33226826 DOI: 10.1021/acs.orglett.0c03552] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Palladium-catalyzed intramolecular tandem cyclization reactions were conducted for the synthesis of densely cis/cis-fused aza-tetracyclic structures. The process involved a palladium(II)-catalyzed aerobic aza-Wacker reaction, followed by a palladium(0)-catalyzed Heck reaction. The effects of the solvent and benzene substitution pattern on the one-pot, two-step cascade reaction were studied systematically, and a probable mechanism was proposed. Strained pentahydrobenzo[f]cyclopenta[hi]indolizin-6-one and racemic γ-lycorane can also be synthesized rapidly using this palladium-catalyzed aza-Wacker-Heck cyclization reaction.
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Affiliation(s)
- Rong-Shiow Tang
- School of Pharmacy, China Medical University, Taichung 406040, Taiwan
| | - Li-Yuan Chen
- School of Pharmacy, China Medical University, Taichung 406040, Taiwan
| | - Chin-Hung Lai
- Department of Medical Applied Chemistry, Chung Shan Medical University, Taichung 40201, Taiwan
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung 406040, Taiwan
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Chen YH, Tang RS, Chen LY, Chuang TH. One-Pot Oxidative Coupling/Decyanation of 6,7-Diphenylindolizine-5-carbonitriles and 2,3-Diphenylquinolizine-4-carbonitriles. J Org Chem 2019; 84:4501-4506. [PMID: 30864446 DOI: 10.1021/acs.joc.9b00041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The one-pot oxidative coupling/decyanation reactions of 6,7-diphenylindolizine-5-carbonitriles and 2,3-diphenylquinolizine-4-carbonitriles were investigated using aryl-aryl oxidative coupling reagents. The phenanthroindolizidinones and phenanthroquinolizidinones were produced in 52-89% yields under VOF3/trifluoroacetic acid or [bis(trifluoroacetoxy)iodo]benzene/BF3-mediated conditions. This represents a mild and efficient approach to construct these types of pentacyclic skeletons from the corresponding cyano group-activated aza-Diels-Alder cycloadducts. A plausible mechanism of the one-pot oxidative coupling/decyanation reaction was proposed.
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Affiliation(s)
- Yi-Hsuan Chen
- School of Pharmacy , China Medical University , Taichung 40402 , Taiwan
| | - Rong-Shiow Tang
- School of Pharmacy , China Medical University , Taichung 40402 , Taiwan
| | - Li-Yuan Chen
- School of Pharmacy , China Medical University , Taichung 40402 , Taiwan
| | - Ta-Hsien Chuang
- School of Pharmacy , China Medical University , Taichung 40402 , Taiwan
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5
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Lai CH, Chang CC, Weng YL, Chuang TH. Synthesis, Experimental and Density Functional Theory (DFT) Studies on Solubility of Camptothecin Derivatives. Molecules 2018; 23:molecules23123170. [PMID: 30513778 PMCID: PMC6320962 DOI: 10.3390/molecules23123170] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Revised: 11/27/2018] [Accepted: 11/30/2018] [Indexed: 11/16/2022] Open
Abstract
Two camptothecin derivatives, 10-cyclohexyl-7-methyl-20(S)-camptothecin and 7-methyl-10-morpholino-20(S)-camptothecin, were synthesized and their differences in solubility were investigated using four chosen solvent systems. Based on our results, 10-cyclohexyl-7-methyl-20(S)-camptothecin exhibited higher solubilities than 7-methyl-10-morpholino-20(S)-camptothecin in polar aprotic solvents. However, these two camptothecin derivatives did not exhibit apparent differences in solubility between 5% dimethyl sulfoxide (DMSO)/95% normal saline co-solvent system and 5% dimethylacetamide (DMAC)/95% normal saline co-solvent system. To rationalize their differences in solubility, we also tried to perform a DFT-B3LYP study to investigate their interaction with one water molecule.
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Affiliation(s)
- Chin-Hung Lai
- Department of Medical Applied Chemistry, Chung Shan Medical University, Taichung 40201, Taiwan.
- Department of Medical Education, Chung Shan Medical University Hospital, Taichung 40201, Taiwan.
| | - Chia-Chin Chang
- Master Program for Pharmaceutical Manufacture, China Medical University, Taichung 40402, Taiwan.
| | - Yi-Lin Weng
- Master Program for Pharmaceutical Manufacture, China Medical University, Taichung 40402, Taiwan.
| | - Ta-Hsien Chuang
- Master Program for Pharmaceutical Manufacture, China Medical University, Taichung 40402, Taiwan.
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
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6
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Chen YH, Lai CH, Sorra K, Chuang TH. Protecting-Group-Free Synthesis of 1-Phenylisoquinolin-4-ols: Thermal Cyclization of Methyl 2-[(Diphenylmethylidene)amino]acetates. J Org Chem 2017; 82:12849-12856. [PMID: 29065266 DOI: 10.1021/acs.joc.7b02240] [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] [Indexed: 11/29/2022]
Abstract
A protecting-group-free synthetic approach to 1-phenylisoquinolin-4-ols was developed by the intramolecular thermal cyclization of methyl 2-[(diphenylmethylidene)amino]acetates. R1 and R2 substituents were found to affect the required reaction temperatures, time, and yields of the cyclized products. The reactivity of the Schiff bases increased upon introduction of α-benzoyl and α-ester groups (R2). The cyclization yield also depended on the position of the R1 substituents on the phenyl groups.
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Affiliation(s)
- Ying-Hui Chen
- School of Pharmacy, China Medical University , Taichung 40402, Taiwan
| | - Chin-Hung Lai
- Department of Medical Applied Chemistry, Chung Shan Medical University , Taichung 40201, Taiwan
| | - Kumaraswamy Sorra
- Medicinal Chemistry Laboratory, Gunapati Venkata Krishnareddy Biosciences Private Limited , Hyderabad 500076, India
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University , Taichung 40402, Taiwan
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Abstract
The partitioned n-hexane, CHCl3, and EtOAc extracts from the crude MeOH extract of Phaius mishmensis showed considerable cytotoxicities against the human breast carcinoma (MCF-7), lung carcinoma (NCI-H460), and central nervous system carcinoma (SF-268) cell lines. Four new compounds, phaindole (1), (7′R,8′R)-phaithrene (2), methyl 3-hydroxy-4,5-dimethoxypropiophenone (3), and methyl hematinate (4), as well as 44 known compounds were isolated from the MeOH extract of Phaius mishmensis. The structures of the compounds were determined using spectroscopic methods.
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Affiliation(s)
- Chen-Wei Jao
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan.
| | - Tzu-Heng Hung
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
| | - Chi-Fen Chang
- Department of Anatomy, School of Medicine, China Medical University, Taichung 40402, Taiwan.
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
- Research Center for Chinese Herbal Medicine, China Medical University, Taichung 40402, Taiwan.
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8
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Sorra K, Lai CH, Feng CY, Wu YC, Pusuluri S, Mukkanti K, Chuang TH. A convenient synthesis of chiral 2-methylenebenzo[ e ][1,4]diazepin-5-ones via a one-pot reductive cyclodehydration with retention of chirality. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.09.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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9
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Chang CF, Li CF, Tsai CC, Chuang TH. Cyano Group Removal from Cyano-Promoted Aza-Diels-Alder Adducts: Synthesis and Structure-Activity Relationship of Phenanthroindolizidines and Phenanthroquinolizidines. Org Lett 2016; 18:638-41. [PMID: 26836702 DOI: 10.1021/acs.orglett.5b03395] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Phenanthroindolizidines and phenanthroquinolizidines were concisely synthesized by the reductive decyanization of cyano-promoted intramolecular aza-Diels-Alder cycloadducts followed by aryl-aryl coupling. Cyano groups were removed from α-aminoacrylonitriles via treatment with sodium borohydride in 2-propanol in almost quantitative yields; a possible mechanism was proposed and examined using D-labeling experiments. A systematic study of the effects of the phenanthrene substitution pattern on the anticancer activity against three human cancer cell lines was discussed.
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Affiliation(s)
- Chi-Fen Chang
- Department of Anatomy, School of Medicine, China Medical University , Taichung 40402, Taiwan
| | - Chien-Fu Li
- School of Pharmacy, China Medical University , Taichung 40402, Taiwan
| | - Chia-Chen Tsai
- School of Pharmacy, China Medical University , Taichung 40402, Taiwan
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University , Taichung 40402, Taiwan.,Research Center for Chinese Herbal Medicine, China Medical University , Taichung 40402, Taiwan
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10
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Chang CF, Ke CY, Wu YC, Chuang TH. Structure-Activity Relationship of Synthetic 2-Phenylnaphthalenes with Hydroxyl Groups that Inhibit Proliferation and Induce Apoptosis of MCF-7 Cancer Cells. PLoS One 2015; 10:e0141184. [PMID: 26492346 PMCID: PMC4619615 DOI: 10.1371/journal.pone.0141184] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [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: 07/13/2015] [Accepted: 10/06/2015] [Indexed: 11/18/2022] Open
Abstract
In this study, six 2-phenylnaphthalenes with hydroxyl groups were synthesized in high yields by the demethylation of the corresponding methoxy-2-phenylnaphthalenes, and one 2-phenylnaphthalene with an amino group was obtained by hydrogenation. All of the 2-phenylnaphthalene derivatives were evaluated for cytotoxicity, and the structure-activity relationship (SAR) against human breast cancer (MCF-7) cells was also determined. The SAR results revealed that cytotoxicity was markedly promoted by the hydroxyl group at the C-7 position of the naphthalene ring. The introduction of hydroxyl groups at the C-6 position of the naphthalene ring and the C-4' position of the phenyl ring fairly enhanced cytotoxicity, but the introduction of a hydroxyl group at the C-3' position of the phenyl ring slightly decreased cytotoxicity. Overall, 6,7-dihydroxy-2-(4'-hydroxyphenyl)naphthalene (PNAP-6h) exhibited the best cytotoxicity, with an IC50 value of 4.8 μM against the MCF-7 cell line, and showed low toxicity toward normal human mammary epithelial cells (MCF-10A). PNAP-6h led to cell arrest at the S phase, most likely due to increasing levels of p21 and p27 and decreasing levels of cyclin D1, CDK4, cyclin E, and CDK2. In addition, PNAP-6h decreased CDK1 and cyclin B1 expression, most likely leading to G2/M arrest, and induced morphological changes, such as nuclear shrinkage, nuclear fragmentation, and nuclear hypercondensation, as observed by Hoechst 33342 staining. PNAP-6h induced apoptosis, most likely by the promotion of Fas expression, increased PARP activity, caspase-7, caspase-8, and caspase-9 expression, the Bax/Bcl-2 ratio, and the phosphorylation of p38, and decreased the phosphorylation of ERK. This study provides the first demonstration of the cytotoxicity of PNAPs against MCF-7 cells and elucidates the mechanism underlying PNAP-induced cytotoxicity.
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Affiliation(s)
- Chi-Fen Chang
- Department of Anatomy, School of Medicine, China Medical University, Taichung, Taiwan
- * E-mail: (CFC); (THC)
| | - Ci-Yi Ke
- Department of Medical Laboratory Science and Biotechnology, China Medical University, Taichung, Taiwan
| | - Yang-Chang Wu
- School of Pharmacy, China Medical University, Taichung, Taiwan
- Research Center for Chinese Herbal Medicine, China Medical University, Taichung, Taiwan
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung, Taiwan
- Research Center for Chinese Herbal Medicine, China Medical University, Taichung, Taiwan
- * E-mail: (CFC); (THC)
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Chang CF, Hsu YL, Lee CY, Wu CH, Wu YC, Chuang TH. Isolation and cytotoxicity evaluation of the chemical constituents from Cephalantheropsis gracilis. Int J Mol Sci 2015; 16:3980-9. [PMID: 25686035 PMCID: PMC4346938 DOI: 10.3390/ijms16023980] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [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: 01/15/2015] [Revised: 02/02/2015] [Accepted: 02/02/2015] [Indexed: 11/23/2022] Open
Abstract
Cephalantheropsis gracilis afforded five new compounds: cephalanthrin-A (1), cephalanthrin-B (2), cephathrene-A (3), cephathrene-B (4), methyl 2-(aminocarbonyl)phenylcarbamate (5), and 52 known compounds. The structures of the new compounds were determined by spectroscopic analysis. Among the compounds isolated, tryptanthrin (6), phaitanthrin A (7), cephalinone D (19), and flavanthrin (30) showed significant cytotoxicity against MCF-7, NCI-H460, and SF-268 cell lines.
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Affiliation(s)
- Chi-Fen Chang
- Department of Anatomy, School of Medicine, China Medical University, Taichung 40402, Taiwan.
| | - Yu-Lin Hsu
- Department of Chemistry, National Cheng Kung University, Tainan 70101, Taiwan.
| | - Chao-Ying Lee
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
| | - Chia-Hua Wu
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
| | - Yang-Chang Wu
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
- Research Center for Chinese Herbal Medicine, China Medical University, Taichung 40402, Taiwan.
- Chinese Medicine Research and Development Center, China Medical University Hospital, Taichung 40402, Taiwan.
- Graduate Institute of Natural Products, Kaohsiung Medical University, Kaohsiung 80708, Taiwan.
- Center of Molecular Medicine, China Medical University Hospital, Taichung 40402, Taiwan.
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan.
- Research Center for Chinese Herbal Medicine, China Medical University, Taichung 40402, Taiwan.
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13
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Chuang TH, Li CF, Lee HZ, Wen YC. Direct Conversion of 1-(2-Bromobenzoyl)isoquinolines to Dibenzo[de,g]quinolin-7-ones via Reductive Photocyclization. J Org Chem 2013; 78:4974-84. [PMID: 23611299 DOI: 10.1021/jo400645g] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Ta-Hsien Chuang
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung, 40402 Taiwan, Republic of China
| | - Chien-Fu Li
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung, 40402 Taiwan, Republic of China
| | - Hong-Zin Lee
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung, 40402 Taiwan, Republic of China
| | - Yu-Chia Wen
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung, 40402 Taiwan, Republic of China
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14
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Sorra K, Chang CF, Pusuluri S, Mukkanti K, Laiu MC, Bao BY, Su CH, Chuang TH. Synthesis and cytotoxicity testing of new amido-substituted triazolopyrrolo[2,1-c][1,4]benzodiazepine (PBDT) derivatives. Molecules 2012; 17:8762-72. [PMID: 22832878 PMCID: PMC6269039 DOI: 10.3390/molecules17088762] [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] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2012] [Revised: 07/16/2012] [Accepted: 07/18/2012] [Indexed: 11/16/2022] Open
Abstract
A series of amido-substituted triazolopyrrolo[2,1-c][1,4]benzodiazepine (PBDT) derivatives was synthesized from isatoic anhydride, and their cytotoxicity against the MRC-5 and Mahlavu cell lines was evaluated. The results suggest that compound PBDT-7i with the meta-trifluoromethylbenzoyl substituent can selectively inhibit the growth of Mahlavu cells and has low toxicity towards MRC-5 cells.
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Affiliation(s)
- Kumaraswamy Sorra
- Medicinal Chemistry Laboratory, GVK Biosciences Private Limited, Plot No. 5C, IDA Uppal, Hyderabad 500039, AP, India; E-Mail: (S.P.)
- Chemistry Division, Institute of Science and Technology, JNT University, Kukatpally, Hyderabad 500072, AP, India
| | - Chi-Fen Chang
- Department of Anatomy and Cell Biology, College of Medicine, National Taiwan University, 1-1, Jen-Ai Road, Taipei 100, Taiwan; E-Mail:
| | - Srinivas Pusuluri
- Medicinal Chemistry Laboratory, GVK Biosciences Private Limited, Plot No. 5C, IDA Uppal, Hyderabad 500039, AP, India; E-Mail: (S.P.)
| | - Khagga Mukkanti
- Chemistry Division, Institute of Science and Technology, JNT University, Kukatpally, Hyderabad 500072, AP, India
| | - Min-Chiau Laiu
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; E-Mail:
| | - Bo-Ying Bao
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan; E-Mail:
| | - Chia-Hao Su
- Center for Translational Research in Biomedical Sciences, Kaohsiung Chang Gung Memorial Hospital, Kaohsiung 833, Taiwan; E-Mail:
| | - Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung 40402, Taiwan; E-Mail:
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15
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Chuang TH, Chang WY, Li CF, Wen YC, Tsai CC. Substituent Effects on the Iodine-Catalyzed Thermal Cyclization of 3,4-Diphenylbuta-1,3-dienyl Isocyanates: Mechanistic Studies. J Org Chem 2011; 76:9678-86. [DOI: 10.1021/jo2017247] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ta-Hsien Chuang
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung 40402, Taiwan, Republic of China
| | - Wei-Yu Chang
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung 40402, Taiwan, Republic of China
| | - Chien-Fu Li
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung 40402, Taiwan, Republic of China
| | - Yu-Chia Wen
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung 40402, Taiwan, Republic of China
| | - Chia-Chen Tsai
- School of Pharmacy, China Medical University, No. 91, Hsueh-Shih Road,
Taichung 40402, Taiwan, Republic of China
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16
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Chuang TH, Chen YC, Pola S. Use of the Curtius Rearrangement of Acryloyl Azides in the Synthesis of 3,5-Disubstituted Pyridines: Mechanistic Studies. J Org Chem 2010; 75:6625-30. [DOI: 10.1021/jo101394c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ta-Hsien Chuang
- School of Pharmacy, China Medical University, Taichung, 40402, Taiwan, Republic of China
| | - Yu-Chi Chen
- Department of Cosmetic Science, Vanung University, Chung-Li, Tao-Yuan 32045, Taiwan, Republic of China
| | - Someshwar Pola
- Department of Chemistry, Kakatiya University, Warangal, India
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17
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Chuang TH, Yang CH, Kao PC. Efficient red-emitting cyclometalated iridium(III) complex and applications of organic light-emitting diode. Inorganica Chim Acta 2009. [DOI: 10.1016/j.ica.2009.08.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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18
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Wu CM, Yang CW, Lee YZ, Chuang TH, Wu PL, Chao YS, Lee SJ. Tylophorine arrests carcinoma cells at G1 phase by downregulating cyclin A2 expression. Biochem Biophys Res Commun 2009; 386:140-5. [DOI: 10.1016/j.bbrc.2009.05.138] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2009] [Accepted: 05/30/2009] [Indexed: 10/20/2022]
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19
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Huang HH, Hsieh HH, Wu CC, Lin CC, Chou PT, Chuang TH, Wen YS, Chow TJ. Thermal generation of pentacene from soluble precursors through expulsion of carbon dioxide. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2008.05.061] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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20
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Chuang TH, Hsieh HH, Chen CK, Wu CC, Lin CC, Chou PT, Chao TH, Chow TJ. Photogeneration and Thermal Generation of Pentacene from Soluble Precursors for OTFT Applications. Org Lett 2008; 10:2869-72. [DOI: 10.1021/ol8010419] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Ta-Hsien Chuang
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Hsing-Hung Hsieh
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Chang-Ken Chen
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Chung-Chih Wu
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Chao-Chen Lin
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Pi-Tai Chou
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Ting-Han Chao
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
| | - Tahsin J. Chow
- Institute of Chemistry, Academia Sinica, Taipei 115, Taiwan, Department of Electrical Engineering and Graduate Institute of Electronics Engineering, National Taiwan University, Taipei 106, Taiwan, Department of Chemistry, National Taiwan University, Taipei 106, Taiwan, and Department of Chemistry, National Taiwan Normal University, Taipei 106, Taiwan
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21
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Ho HY, Hung CC, Chuang TH, Wang WL. Identification and Synthesis of the Sex Pheromone of the Passionvine Mealybug, Planococcus minor (Maskell). J Chem Ecol 2007; 33:1986-96. [PMID: 17885792 DOI: 10.1007/s10886-007-9361-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [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: 06/05/2007] [Revised: 08/15/2007] [Accepted: 08/31/2007] [Indexed: 10/22/2022]
Abstract
The sex pheromone of the mealybug, Planococcus minor was isolated by fractionation of crude pheromone extract obtained by aeration of virgin females. The pheromone was identified as the irregular terpenoid, 2-isopropyl-5-methyl-2,4-hexadienyl acetate, by mass spectrometry, microchemical tests, and (1)H NMR spectroscopy. The stereochemistry of the pheromone was assigned as (E) by comparison with synthetic standards of known geometry. The compound was highly attractive to males in laboratory bioassays, whereas the (Z)-isomer appeared to antagonize attraction.
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Affiliation(s)
- Hsiao-Yung Ho
- Institute of Cellular and Organismic Biology, Academia Sinica, Taipei, Taiwan 11526, Republic of China.
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22
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Yang CW, Chuang TH, Wu PL, Huang WH, Lee SJ. Anti-inflammatory effects of 7-methoxycryptopleurine and structure–activity relations of phenanthroindolizidines and phenanthroquinolizidines. Biochem Biophys Res Commun 2007; 354:942-8. [PMID: 17274949 DOI: 10.1016/j.bbrc.2007.01.065] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [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: 01/12/2007] [Accepted: 01/13/2007] [Indexed: 11/27/2022]
Abstract
A cryptopleurine analogue, 7-methoxycryptopleurine, a phenanthroquinolizidine, was first found to exert potent anti-inflammatory activity in vitro and in vivo as well as have remarkable cytotoxic activity against cancer cells. The non-planar structure between the two major moieties, phenanthrene and indolizidine/quinolizidine, played a crucial role in the activity of phenanthroindolizidines or phenanthroquinolizidines in terms of cytotoxic effects on cancer cells and anti-inflammatory activity. We also showed that increase in planarity and rigidity of the indolizidine/quinolizidine moiety and change of the amine group into an amide by introducing a keto group to phenanthroindolizidines or phenanthroquinolizidines at the equivalent position 9 of tylophorine significantly reduced their activities. Moreover, in general, phenanthroquinolizidines are more potent than their respective phenanthroindolizines.
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Affiliation(s)
- Cheng-Wei Yang
- Division of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Miaoli county, Taiwan, ROC
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23
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Abstract
Bioassay-guided fractionation of the MeOH extract of the leaves of Grevillea robusta led to the isolation of six new 5-alkylresorcinols, gravicycle (1), dehydrogravicycle (2), bisgravillol (3), dehydrobisgravillol (4), dehydrograviphane (5), and methyldehydrograviphane (6), as well as eight known compounds. The structures of these compounds were determined by spectroscopic and chemical methods. Graviphane (7) and methylgraviphane (8) were isolated in the pure form for the first time from a natural source. The compounds all showed marginal cytotoxicity against MCF-7, NCI-H460, and SF-268 cell lines.
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Affiliation(s)
- Ta-Hsien Chuang
- Department of Chemistry, National Cheng Kung University, Tainan, 701, Taiwan, Republic of China
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24
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Chuang TH, Lee SJ, Yang CW, Wu PL. Expedient synthesis and structure-activity relationships of phenanthroindolizidine and phenanthroquinolizidine alkaloids. Org Biomol Chem 2006; 4:860-7. [PMID: 16493470 DOI: 10.1039/b516152e] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [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: 11/21/2022]
Abstract
The total synthesis of alkaloids phenanthroindolizidine 1a, tylophorine 1b, and phenanthroquinolizidine 1c, has been achieved in 46%, 49%, and 42% overall yield, respectively, starting from the corresponding phenanthrene-9-carboxaldehyde. Compound exhibited potent inhibition activity in three human cancer cell lines, with IC(50) values ranging from 104 to 130 nM. The structure-activity relations of these alkaloids and some of their synthetic intermediates against the three cell lines were also described.
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Affiliation(s)
- Ta-Hsien Chuang
- Department of Chemistry, National Cheng Kung University, Tainan, 701, Taiwan, ROC
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25
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Affiliation(s)
- Yu-Ting Huang
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
| | - Ta-Hsien Chuang
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
| | - Yu-Lin Shu
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
| | - Yi-Chun Kuo
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
| | - Pei-Lin Wu
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
| | - Cheng-Hsien Yang
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
| | - I-Wen Sun
- Department of Chemistry, National Cheng Kung University, Tainan, Taiwan, 70101, Republic of China
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26
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Wu PL, Chuang TH, He CX, Wu TS. Cytotoxicity of phenylpropanoid esters from the stems of Hibiscus taiwanensis. Bioorg Med Chem 2004; 12:2193-7. [PMID: 15080919 DOI: 10.1016/j.bmc.2004.02.020] [Citation(s) in RCA: 20] [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] [Received: 12/09/2003] [Revised: 02/16/2004] [Accepted: 02/17/2004] [Indexed: 10/26/2022]
Abstract
The separation of an extract prepared from the stems of the previously uninvestigated Hibiscus taiwanensis led to the isolation of three new phenylpropanoid esters, (7S,8S)-demethylcarolignan E (1), hibiscuwanin A (2), hibiscuwanin B (3), in addition to eight known ones. The structures of these compounds were elucidated by spectroscopic and chemical transformation studies. In cytotoxicity evaluation of the isolates, 9,9'-O-feruloyl-(-)-secoisolaricinresinol (8) showed strong cytotoxic activity against human lung carcinoma and breast carcinoma cell lines in an in vitro cytotoxicity assay with EC(50) values of 1.8 and 3.9 microg/mL, respectively.
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Affiliation(s)
- Pei-Lin Wu
- Department of Chemistry, National Cheng Kung University, Tainan 701, Taiwan, ROC.
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27
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Werts C, Tapping RI, Mathison JC, Chuang TH, Kravchenko V, Saint Girons I, Haake DA, Godowski PJ, Hayashi F, Ozinsky A, Underhill DM, Kirschning CJ, Wagner H, Aderem A, Tobias PS, Ulevitch RJ. Leptospiral lipopolysaccharide activates cells through a TLR2-dependent mechanism. Nat Immunol 2001; 2:346-52. [PMID: 11276206 DOI: 10.1038/86354] [Citation(s) in RCA: 484] [Impact Index Per Article: 21.0] [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: 12/11/2022]
Abstract
Leptospira interrogans are zoonotic pathogens that have been linked to a recent increased incidence of morbidity and mortality in highly populated tropical urban centers. They are unique among invasive spirochetes in that they contain outer membrane lipopolysaccharide (LPS) as well as lipoproteins. Here we show that both these leptospiral outer membrane constituents activate macrophages through CD14 and the Toll-like receptor 2 (TLR2). Conversely, it seems that TLR4, a central component for recognition of Gram-negative LPS, is not involved in cellular responses to L. interrogans. We also show that for intact L. interrogans, it is LPS, not lipoprotein, that constitutes the predominant signaling component for macrophages through a TLR2 pathway. These data provide a basis for understanding the innate immune response caused by leptospirosis and demonstrate a new ligand specificity for TLR2.
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Affiliation(s)
- C Werts
- Department of Immunology, The Scripps Research Institute, La Jolla, CA 92037, USA
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28
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Golovanov AP, Chuang TH, DerMardirossian C, Barsukov I, Hawkins D, Badii R, Bokoch GM, Lian LY, Roberts GC. Structure-activity relationships in flexible protein domains: regulation of rho GTPases by RhoGDI and D4 GDI. J Mol Biol 2001; 305:121-35. [PMID: 11114252 DOI: 10.1006/jmbi.2000.4262] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [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: 11/22/2022]
Abstract
The guanine dissociation inhibitors RhoGDI and D4GDI inhibit guanosine 5'-diphosphate dissociation from Rho GTPases, keeping these small GTPases in an inactive state. The GDIs are made up of two domains: a flexible N-terminal domain of about 70 amino acid residues and a folded 134-residue C-terminal domain. Here, we characterize the conformation of the N-terminal regions of both RhoGDI and D4GDI using a series of NMR experiments which include (15)N relaxation and amide solvent accessibility measurements. In each protein, two regions with tendencies to form helices are identified: residues 36 to 58 and 9 to 20 in RhoGDI, and residues 36 to 57 and 20 to 25 in D4GDI. To examine the functional roles of the N-terminal domain of RhoGDI, in vitro and in vivo functional assays have been carried out with N-terminally truncated proteins. These studies show that the first 30 amino acid residues are not required for inhibition of GDP dissociation but appear to be important for GTP hydrolysis, whilst removal of the first 41 residues completely abolish the ability of RhoGDI to inhibit GDP dissociation. The combination of structural and functional studies allows us to explain why RhoGDI and D4GDI are able to interact in similar ways with the guanosine 5'-diphosphate-bound GTPase, but differ in their ability to regulate GTP-bound forms; these functional differences are attributed to the conformational differences of the N-terminal domains of the guanosine 5'-diphosphate dissociation inhibitors. Therefore, the two transient helices, appear to be associated with different biological effects of RhoGDI, providing a clear example of structure-activity relationships in a flexible protein domain.
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Affiliation(s)
- A P Golovanov
- Department of Biochemistry and Biological NMR Centre, University of Leicester, Leicester, LE1 7RH, UK
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29
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Chuang TH, Sharpless KB. Applications of aziridinium ions. Selective syntheses of alpha, beta-diamino esters, alpha-sulfanyl-beta-amino esters, beta-lactams, and 1,5-benzodiazepin-2-one. Org Lett 2000; 2:3555-7. [PMID: 11073643 DOI: 10.1021/ol000221+] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [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: 11/28/2022]
Abstract
A variety of nucleophiles, including amines, thiolates, and alkoxides, were employed to open the aziridinium ions Az. The latter are opened stereospecifically and regioselectively at the C-3 position by a wide range of amines, and thiolate nucleophiles attack predominately at the C-2 position. Poor regioselectivities (ca. 1:1) were observed using nucleophiles derived from phenols, carboxylic acids, and imides. Base-mediated ring closure of the aziridinium opening products, from primary amines, gave beta-lactams and a 1, 5-benzodiazepin-2-one in high yields.
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Affiliation(s)
- T H Chuang
- Department of Chemistry and the Skaggs Institute for Chemical Biology, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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30
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Chuang TH, Ulevitch RJ. Cloning and characterization of a sub-family of human toll-like receptors: hTLR7, hTLR8 and hTLR9. Eur Cytokine Netw 2000; 11:372-8. [PMID: 11022120] [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: 02/17/2023]
Abstract
Members of the Toll-like receptor family are essential components of the innate immune system. Herein we report the molecular cloning and characterization of three novel human Toll-like receptors (hTLRs) designated hTLR7, hTLR8, and hTLR9. Human TLR7-9, like the previously described members hTLR1-6 contain an ectodomain with multiple leucine-rich repeats (LRRs) and a cytoplasmic domain homologous to that of the human interleukin-1 (IL-1) receptor. When compared with hTLR1-6, the hTLR7-9 has a higher molecular weight largely as a result of a longer ectodomain. Phylogenetic analysis shows that hTLR7-9 belong to a new sub-family of the hTLRs. Analysis of mRNA expression at the tissue levels shows differential expression patterns; hTLR7 is predominantly expressed in lung, placenta and spleen, hTLR8 is more abundant in lung, peripheral blood leukocytes, and hTLR9 is preferentially expressed in immune cell rich tissues, such as spleen, lymph node, bone marrow and peripheral blood leukocytes. The hTLR7 and hTLR8 genes are located on the sex chromosome X, hTLR9 gene is located on chromosome 3. Expression of constitutively active hTLR7-9 stimulates an NF-kappaB signaling pathway indirectly supporting the contention that these receptors are involved in cellular responses to stimuli, which activate innate immunity.
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Affiliation(s)
- T H Chuang
- Department of Immunology, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037 USA
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31
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Subauste MC, Von Herrath M, Benard V, Chamberlain CE, Chuang TH, Chu K, Bokoch GM, Hahn KM. Rho family proteins modulate rapid apoptosis induced by cytotoxic T lymphocytes and Fas. J Biol Chem 2000; 275:9725-33. [PMID: 10734125 DOI: 10.1074/jbc.275.13.9725] [Citation(s) in RCA: 207] [Impact Index Per Article: 8.6] [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: 01/26/2023] Open
Abstract
Little is known about the role of Rho proteins in apoptosis produced by stimuli evolved specifically to produce apoptosis, such as granzymes from cytotoxic T lymphocytes (CTLs) and Fas. Here we demonstrate that all three Rho family members are involved in CTL- and Fas-induced killing. Dominant-negative mutants of each Rho family member and Clostridium difficile toxin B, an inhibitor of all family members, strongly inhibited the susceptibility of cells to CTL- and Fas-induced apoptosis. Fas-induced caspase-3 activation was inhibited by C. difficile toxin. Activated mutants of each GTPase increased susceptibility to apoptosis, and activation of Cdc42 increased within 5 min of Fas stimulation. In contrast, during the time required for CTL and Fas killing, no apoptosis was produced by dominant-negative or activated mutants or by C. difficile toxin alone. Inhibition of actin polymerization using latrunculin A reduced the ability of constitutively active GTPase mutants to stimulate apoptosis and blocked Fas-induced activation of caspase-3. Furthermore, the ability of Rac to enhance apoptosis was decreased by point mutations reported to block Rac induction of actin polymerization. Rho family proteins may regulate apoptosis through their effects on the actin cytoskeleton.
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Affiliation(s)
- M C Subauste
- Department of Cell Biology, Division of Virology, Scripps Research Institute, La Jolla, California 92037, USA
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32
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Abstract
[formula: see text] alpha,beta-Diamino esters are readily prepared through stereospecific and regioselective opening of an aziridinium ion intermediate with a variety of amines. The aziridinium ion is generated from the epoxide in two steps.
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Affiliation(s)
- T H Chuang
- Department of Chemistry, Scripps Research Institute, La Jolla, California 92037, USA
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33
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Rudel T, Zenke FT, Chuang TH, Bokoch GM. p21-activated kinase (PAK) is required for Fas-induced JNK activation in Jurkat cells. J Immunol 1998; 160:7-11. [PMID: 9551947] [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: 02/07/2023]
Abstract
The process of apoptosis is a critical component of normal immune system development and homeostasis, and in many cells this involves signaling through the c-Jun amino terminal kinase (JNK) pathway. In Jurkat T cells, Fas-induced JNK activity is dependent upon activation of the caspase cascades known to be central components of the apoptotic program. We show in Jurkat cell lines expressing a dominant negative PAK construct that PAK signaling is necessary for JNK activation in response to Fas receptor cross-linking. Inhibition of JNK activation induced by Fas does not impair cell death as assessed by DNA fragmentation. However, expression of the catalytically active C terminus of PAK2, which is generated through caspase action during Fas-mediated apoptosis, induces Jurkat cell apoptosis. We conclude that PAK activity resulting from caspase-mediated cleavage is a necessary component of JNK activation induced by Fas receptor signaling and that PAK2 can contribute to the induction of cell death.
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Affiliation(s)
- T Rudel
- The Scripps Research Institute, Department of Immunology, La Jolla, CA 92037, USA
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34
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Chuang TH, Hahn KM, Lee JD, Danley DE, Bokoch GM. The small GTPase Cdc42 initiates an apoptotic signaling pathway in Jurkat T lymphocytes. Mol Biol Cell 1997; 8:1687-98. [PMID: 9307966 PMCID: PMC305729 DOI: 10.1091/mbc.8.9.1687] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [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: 02/05/2023] Open
Abstract
Apoptosis plays an important role in regulating development and homeostasis of the immune system, yet the elements of the signaling pathways that control cell death have not been well defined. When expressed in Jurkat T cells, an activated form of the small GTPase Cdc42 induces cell death exhibiting the characteristics of apoptosis. The death response induced by Cdc42 is mediated by activation of a protein kinase cascade leading to stimulation of c-Jun amino terminal kinase (JNK). Apoptosis initiated by Cdc42 is inhibited by dominant negative components of the JNK cascade and by reagents that block activity of the ICE protease (caspase) family, suggesting that stimulation of the JNK kinase cascade can lead to caspase activation. The sequence of morphological events observed typically in apoptotic cells is modified in the presence of activated Cdc42, suggesting that this GTPase may account for some aspects of cytoskeletal regulation during the apoptotic program. These data suggest a means through which the biochemical and morphological events occurring during apoptosis may be coordinately regulated.
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Affiliation(s)
- T H Chuang
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037, USA
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35
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Danley DE, Chuang TH, Bokoch GM. Defective Rho GTPase regulation by IL-1 beta-converting enzyme-mediated cleavage of D4 GDP dissociation inhibitor. J Immunol 1996; 157:500-3. [PMID: 8752894] [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] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
GTPases of the Rho family regulate many aspects of inflammatory cell activity, including motility, formation of toxic oxygen metabolites, and generation of proinflammatory cytokines. Defective regulation of such signaling pathways leads to a variety of acute and chronic inflammatory disorders, although the mechanisms by which this occurs have not been well defined. We describe in this work specific proteolytic cleavage of D4 GDI, a critical regulator of Rho GTPase activity in inflammatory leukocytes, by IL-1 beta-converting enzyme (ICE). Cleavage of D4 GDI by ICE occurs at Asp55, leading to the formation of the truncated D4 that is unable to effectively bind and regulate GTPases of the Rho family. Our data suggest that activation of ICE protease(s) at inflammatory sites leads to defective Rho GTPase regulation. Release of these critical regulatory proteins may contribute substantially to the inflammatory response at these sites, exacerbating and perpetuating the resulting tissue damage.
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Affiliation(s)
- D E Danley
- Department of Molecular Sciences, Pfizer Central Research, Groton, CT 06340, USA
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36
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Danley DE, Chuang TH, Bokoch GM. Defective Rho GTPase regulation by IL-1 beta-converting enzyme-mediated cleavage of D4 GDP dissociation inhibitor. The Journal of Immunology 1996. [DOI: 10.4049/jimmunol.157.2.500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Abstract
GTPases of the Rho family regulate many aspects of inflammatory cell activity, including motility, formation of toxic oxygen metabolites, and generation of proinflammatory cytokines. Defective regulation of such signaling pathways leads to a variety of acute and chronic inflammatory disorders, although the mechanisms by which this occurs have not been well defined. We describe in this work specific proteolytic cleavage of D4 GDI, a critical regulator of Rho GTPase activity in inflammatory leukocytes, by IL-1 beta-converting enzyme (ICE). Cleavage of D4 GDI by ICE occurs at Asp55, leading to the formation of the truncated D4 that is unable to effectively bind and regulate GTPases of the Rho family. Our data suggest that activation of ICE protease(s) at inflammatory sites leads to defective Rho GTPase regulation. Release of these critical regulatory proteins may contribute substantially to the inflammatory response at these sites, exacerbating and perpetuating the resulting tissue damage.
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Affiliation(s)
- D E Danley
- Department of Molecular Sciences, Pfizer Central Research, Groton, CT 06340, USA
| | - T H Chuang
- Department of Molecular Sciences, Pfizer Central Research, Groton, CT 06340, USA
| | - G M Bokoch
- Department of Molecular Sciences, Pfizer Central Research, Groton, CT 06340, USA
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37
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Abstract
Pinocytosis and membrane ruffling are among the earliest and most dramatic cellular responses to stimulation by growth factors or other mitogens. The small Ras-related G proteins Rho and Rac have a regulatory role in membrane ruffling and activated Rho has been shown to stimulate pinocytosis when microinjected into Xenopus oocytes. In contrast to these well established effects of Rho and Rac on plasma membrane morphology and bulk pinocytosis, there has been no evidence for their involvement in the regulation of receptor-mediated endocytosis in clathrin-coated pits. Here we show that activated Rho and Rac inhibit transferrin-receptor-mediated endocytosis when expressed in intact cells. Furthermore, we have reconstituted these effects in a cell-free system and established that Rho and Rac can regulate clathrin-coated vesicle formation.
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Affiliation(s)
- C Lamaze
- Department of Cell Biology, The Scripps Research Institute, La Jolla, California 92037, USA
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38
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Martin SJ, Amarante-Mendes GP, Shi L, Chuang TH, Casiano CA, O'Brien GA, Fitzgerald P, Tan EM, Bokoch GM, Greenberg AH, Green DR. The cytotoxic cell protease granzyme B initiates apoptosis in a cell-free system by proteolytic processing and activation of the ICE/CED-3 family protease, CPP32, via a novel two-step mechanism. EMBO J 1996; 15:2407-16. [PMID: 8665848 PMCID: PMC450172] [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: 02/01/2023] Open
Abstract
The major mechanism of cytotoxic lymphocyte killing involves the directed release of granules containing perforin and a number of proteases onto the target cell membrane. One of these proteases, granzyme B, has an unusual substrate site preference for Asp residues, a property that it shares with members of the emerging interleukin-1beta-converting enzyme (ICE)/CED-3 family of proteases. Here we show that granzyme B is sufficient to reproduce rapidly all of the key features of apoptosis, including the degradation of several protein substrates, when introduced into Jurkat cell-free extracts. Granzyme B-induced apoptosis was neutralized by a tetrapeptide inhibitor of the ICE/CED-3 family protease, CPP32, whereas a similar inhibitor of ICE had no effect. Granzyme B was found to convert CPP32, but not ICE, to its active form by cleaving between the large and small subunits of the CPP32 proenzyme, resulting in removal of the prodomain via an autocatalytic step. The cowpox virus protein CrmA, a known inhibitor of ICE family proteases as well as granzyme B, inhibited granzyme B-mediated CPP32 processing and apoptosis. These data demonstrate that CPP32 activation is a key event during apoptosis initiated by granzyme B.
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Affiliation(s)
- S J Martin
- La Jolla Institute for Allergy and Immunology, CA 92037, USA
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Na S, Chuang TH, Cunningham A, Turi TG, Hanke JH, Bokoch GM, Danley DE. D4-GDI, a substrate of CPP32, is proteolyzed during Fas-induced apoptosis. J Biol Chem 1996; 271:11209-13. [PMID: 8626669 DOI: 10.1074/jbc.271.19.11209] [Citation(s) in RCA: 183] [Impact Index Per Article: 6.5] [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: 01/31/2023] Open
Abstract
Apoptosis (programmed cell death) is a fundamental process for normal development of multicellular organisms, and is involved in the regulation of the immune system, normal morphogenesis, and maintenance of homeostasis, ICE/CED-3 family cysteine proteases have been implicated directly in apoptosis, but relatively few of the substrates through which their action is mediated have been identified. Here we report that D4-GDI, an abundant hematopoietic cell GDP dissociation inhibitor for the Ras-related Rho family GTPases, is a substrate of the apoptosis protease CPP32/Yama/Apopain. D4-GDI was rapidly truncated to a 23-kDa fragment in Jurkat cells with kinetics that parallel the onset of apoptosis following Fas cross-linking with agonistic antibody or treatment with staurosporine. Fas- and staurosporine-induced apoptosis as well as cleavage of D4-GDI were inhibited by the ICE inhibitor, YVAD-cmk. D4-GDI was cleaved in vitro by recombinant CPP32 expressed in Escherichia coli to form a 23-kDa fragment. The CPP32-mediated cleavage of D4-GDI was completely inhibited by 1 microM DEVD-CHO, a reported selective inhibitor of CPP32. In contrast, the ICE-selective inhibitors, YVAD-CHO or YVAD-cmk, did not inhibit CPP32-mediated D4-GDI cleavage at concentrations up to 50 microM. N-terminal sequencing of the 23-kDa D4-GDI fragment demonstrated that D4-GDI was cleaved between Asp19 and Ser20 of the poly(ADP-ribose) polymerase-like cleavage sequence DELD19S. These data suggest that regulation by D4-GDI of Rho family GTPases may be disrupted during apoptosis by CPP32-mediated cleavage of the GDI protein.
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Affiliation(s)
- S Na
- Department of Molecular Sciences, Pfizer Inc., Groton, Connecticut 06340, USA
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Chuang TH, Xu X, Kaartinen V, Heisterkamp N, Groffen J, Bokoch GM. Abr and Bcr are multifunctional regulators of the Rho GTP-binding protein family. Proc Natl Acad Sci U S A 1995; 92:10282-6. [PMID: 7479768 PMCID: PMC40780 DOI: 10.1073/pnas.92.22.10282] [Citation(s) in RCA: 127] [Impact Index Per Article: 4.4] [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: 01/25/2023] Open
Abstract
Philadelphia chromosome-positive leukemias result from the fusion of the BCR and ABL genes, which generates a functional chimeric molecule. The Abr protein is very similar to Bcr but lacks a structural domain which may influence its biological regulatory capabilities. Both Abr and Bcr have a GTPase-activating protein (GAP) domain similar to those found in other proteins that stimulate GTP hydrolysis by members of the Rho family of GTP-binding proteins, as well as a region of homology with the guanine nucleotide dissociation-stimulating domain of the DBL oncogene product. We purified as recombinant fusion proteins the GAP- and Dbl-homology domains of both Abr and Bcr. The Dbl-homology domains of Bcr and Abr were active in stimulating GTP binding to CDC42Hs, RhoA, Rac1, and Rac2 (rank order, CDC42Hs > RhoA > Rac1 = Rac2) but were inactive toward Rap1A and Ha-Ras. Both Bcr and Abr acted as GAPs for Rac1, Rac2, and CDC42Hs but were inactive toward RhoA, Rap1A, and Ha-Ras. Each individual domain bound in a noncompetitive manner to GTP-binding protein substrates. These data suggest the multifunctional Bcr and Abr proteins might interact simultaneously and/or sequentially with members of the Rho family to regulate and coordinate cellular signaling.
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Affiliation(s)
- T H Chuang
- Department of Immunology, Scripps Research Institute, La Jolla, CA 92037, USA
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41
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Abstract
In mink lung CCL64 epithelial cells the rate of synthesis of plasminogen activator inhibitor type I (PAI-1) increases 10-100-fold within 3 h in response to 12-O-tetradecanoyl phorbol-13-acetate (PMA). The PAI-1 gene is regulated transcriptionally. Parallel studies of the time-courses of PAI-1 synthesis and secretion and of mRNA accumulation indicate that the amount of secreted PAI-1 produced by the cells is tightly coupled to the level of its transcript. The half-life of the PAI-1 mRNA was found to be 25 min which is much shorter than previously reported for PAI-1 in other cells. Actinomycin D, which is commonly used to determine mRNA half-life, stabilized the PAI-1 mRNA. Cycloheximide also stabilized the mRNA. The short half-life and the superinducibility of PAI mRNA are properties shared with rapidly degraded mRNAs encoding protooncoproteins. A 2.97-kb cDNA clone containing the entire coding sequence of PAI-1 was isolated from a cDNA library made from mink lung CCL64 epithelial cells stimulated with PMA. The PAI-1 cDNA contains a long 3'-untranslated region (UTR) of 1720 bp whose sequence is highly conserved among PAI-1 mRNAs from different species. The PAI-1 mRNA also contains several AUUUA pentamer sequences which are the features of an A+U-rich regulatory element such as is found on the fos protooncogene mRNA. Upstream of one of these AUUUA pentamers are several highly conserved sequences that are also found in the 3' UTR of the fos and integrin receptor alpha-subunit mRNAs.(ABSTRACT TRUNCATED AT 250 WORDS)
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Affiliation(s)
- T H Chuang
- Department of Biochemistry and Biophysics, Iowa State University, Ames 50011, USA
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Bokoch GM, Bohl BP, Chuang TH. Guanine nucleotide exchange regulates membrane translocation of Rac/Rho GTP-binding proteins. J Biol Chem 1994; 269:31674-9. [PMID: 7989340] [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: 01/28/2023] Open
Abstract
GTP-binding proteins of the Rho family are maintained as cytosolic complexes with RhoGDI in resting cells, but are released and translocate to the membrane during the course of cell activation. Membrane association of Rac/Rho/CDC42 was specifically induced by GTP analogs and required a heat- and trypsin-labile membrane component. Translocation was associated with the release of Rho family proteins from RhoGDI, but such release did not occur in the absence of membranes, nor was release in the absence of guanosine 5'-O-(thiotriphosphate) (GTP gamma S) sufficient for membrane association. Membrane binding was correlated with exchange of GTP gamma S for GDP on Rac, and only GTP gamma S-bound Rac became membrane localized. We propose that translocation of Rac and other members of the Rho family is controlled by membrane-associated guanine nucleotide exchange factors, providing a mechanism to regulate the release and activation of individual members of the Rho family during cell stimulation.
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Affiliation(s)
- G M Bokoch
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037
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Chuang TH, Xu X, Quilliam LA, Bokoch GM. SmgGDS stabilizes nucleotide-bound and -free forms of the Rac1 GTP-binding protein and stimulates GTP/GDP exchange through a substituted enzyme mechanism. Biochem J 1994; 303 ( Pt 3):761-7. [PMID: 7980444 PMCID: PMC1137612 DOI: 10.1042/bj3030761] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [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: 01/28/2023]
Abstract
The Rac proteins, Rac1 and Rac2, are essential components of the NADPH oxidase system of phagocytes and regulate the actin assembly associated with membrane ruffling. These functions are controlled by the GTP-bound form of Rac. The biochemical interaction between Rac and its only known GDP-dissociation stimulator (termed smgGDS) was characterized. SmgGDS was able to stimulate the incorporation of guanosine 5'-[gamma-thio]-triphosphate GTP[gamma S] into the RhoA, Rac2, Rac1, Rap1A and CDC42Hs GTP-binding proteins, but the activity was greatest toward RhoA and Rac2. Isoprenoid modification of these proteins was not absolutely required for the interaction with smgGDS. Interestingly, the activity of smgGDS toward Rac1 could not be observed in a [3H]GDP/GTP exchange assay under conditions where it stimulated incorporation of GTP[gamma S] into Rac1. We determined that smgGDS prevented the loss of Rac1 activity during the [3H]GDP/GTP exchange assay by demonstrating the ability of smgGDS to inhibit the loss of Rac1 GTP[gamma S]-binding during incubations at 30 degrees C. This stabilizing effect was exactly counterbalanced by the ability of smgGDS to stimulate the release of [3H]GDP from Rac1, thereby producing no net observable effect in the exchange assay. SmgGDS was able to effectively stimulate the release of GDP but not GTP[gamma S] from Rac1. SmgGDS maintains Rac1 in a nucleotide-free form after release of GDP, indicating that the reaction between Rac1 and smgGDS involves a substituted enzyme mechanism.
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Affiliation(s)
- T H Chuang
- Department of Immunology, Scripps Research Institute, La Jolla, CA 92037
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Chuang TH, Bohl BP, Bokoch GM. Biologically active lipids are regulators of Rac.GDI complexation. J Biol Chem 1993; 268:26206-11. [PMID: 8253741] [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: 01/29/2023] Open
Abstract
Members of the Rho family of GTP-binding proteins are localized in the cytosol of cells by complexation with a protein known as (Rho)GDI. We show by sucrose gradient equilibrium sedimentation analysis that all of the Rac protein present in human neutrophil cytosol exists as a complex with (Rho)GDI under non-activating conditions. This interaction can be disrupted in the presence of various lipids which have been shown to have biological activity in a variety of systems, including NADPH oxidase activation. Particularly effective were arachidonic acid, phosphatidic acid, and phosphatidylinositols. These lipids were active at concentrations from 0.5-50 microM and were capable of disrupting complexation of (Rho)GDI with both GDP- and GTP-bound forms of Rac, although the latter were more sensitive to lipid. These data suggest that certain lipids generated in chemoattractant-stimulated neutrophils may play a role in modulating the activity of Rac and thus NADPH oxidase activity.
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Affiliation(s)
- T H Chuang
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037
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45
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46
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Chuang TH, Xu X, Knaus UG, Hart MJ, Bokoch GM. GDP dissociation inhibitor prevents intrinsic and GTPase activating protein-stimulated GTP hydrolysis by the Rac GTP-binding protein. J Biol Chem 1993; 268:775-8. [PMID: 8419353] [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: 01/30/2023] Open
Abstract
The majority of the GTP-binding proteins of the Ras superfamily hydrolyze GTP to GDP very slowly. A notable exception to this are the Rac proteins, which have intrinsic GTPase rates at least 50-fold those of Ras or Rho. A protein (or proteins) capable of inhibiting this GTPase activity exists in human neutrophil cytosol. Since Rac appears to exist normally in neutrophils as a cytosolic protein complexed to (Rho)GDI, we examined the ability of (Rho)GDI to inhibit GTP hydrolysis by Rac. (Rho)GDI produced a concentration-dependent inhibition of GTP hydrolysis by Rac1 that paralleled its ability to inhibit GDP dissociation from the Rac protein. Maximal inhibition occurred at or near equimolar concentrations of the GDI and the Rac substrate. The ability of two molecules exhibiting GTPase activating protein (GAP) activity toward Rac to stimulate GTP hydrolysis was also inhibited by the presence of (Rho)GDI. The inhibitory effect of the GDI could be overcome by increasing the GAP concentration to levels equal to that of the GDI. (Rho)GDI weakly, but consistently, inhibited GTP gamma S (guanosine 5'-3-O-(thio)triphosphate) dissociation from Rac1, confirming an interaction of (Rho)GDI with the GTP-bound form of the protein. These data describe an additional activity of (Rho)GDI and suggest a mechanism by which Rac might be maintained in an active form in vivo in the presence of regulatory GAPs.
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Affiliation(s)
- T H Chuang
- Department of Immunology, Scripps Research Institute, La Jolla, California 92037
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Chen LS, Chen CC, Chang RC, Chuang TH. [Bonded retainer for anterior periodontal splinting]. Zhonghua Ya Yi Xue Hui Za Zhi 1985; 4:55-60. [PMID: 3915703] [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: 01/08/2023]
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48
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Jou YT, Chuang TH, Lan WH, Kwan HW. Talon cusp--report of cases. Zhonghua Ya Yi Xue Hui Za Zhi 1985; 4:15-20. [PMID: 3869075] [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: 01/07/2023]
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49
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Duh BR, Chuang TH, Lan WH. [Evaluation of the accuracy of the Endodontic Meter-S]. Zhonghua Ya Yi Xue Hui Za Zhi 1985; 4:8-14. [PMID: 3869080] [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: 01/07/2023]
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