1
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Gaikwad P, Kemp MG. Cathepsin L inhibition prevents the cleavage of multiple nuclear proteins upon lysis of quiescent human cells. MICROPUBLICATION BIOLOGY 2023; 2022:10.17912/micropub.biology.000716. [PMID: 36606083 PMCID: PMC9807461 DOI: 10.17912/micropub.biology.000716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2022] [Revised: 12/13/2022] [Accepted: 12/14/2022] [Indexed: 01/07/2023]
Abstract
Several studies have indicated a role for cathepsin L (CTSL) proteolytic activity in the nucleus under distinct cellular conditions, including during differentiation, senescence, and quiescence. Here we show that addition of CTSL inhibitors to a cell lysis buffer prevents the cleavage of several nuclear proteins during the lysis of quiescent human cells, including proteins previously thought to have functional relevance in other cell and tissue contexts. These findings suggest that care should be taken to use CTSL inhibitors when lysing cells and tissues containing high levels of CTSL protein to differentiate proteolysis that occurs in vivo versus artifactually in vitro.
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Affiliation(s)
- Prashant Gaikwad
- Department of Pharmcology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH 45435
| | - Michael G. Kemp
- Department of Pharmcology and Toxicology, Wright State University Boonshoft School of Medicine, Dayton, OH 45435
,
Research Service, Dayton VA Medical Center, Dayton, OH 45428
,
Correspondence to: Michael G. Kemp (
)
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2
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Shao M, Lu L, Wang Q, Ma L, Tian X, Li C, Li C, Guo D, Wang Q, Wang W, Wang Y. The multi-faceted role of retinoid X receptor in cardiovascular diseases. Biomed Pharmacother 2021; 137:111264. [PMID: 33761589 DOI: 10.1016/j.biopha.2021.111264] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 01/04/2021] [Accepted: 01/07/2021] [Indexed: 01/14/2023] Open
Abstract
Retinoid X receptors (RXRs) are members of ligand-dependent transcription factors whose effects on a diversity of cellular processes, including cellular proliferation, the immune response, and lipid and glucose metabolism. Knock out of RXRα causes a hypoplasia of the myocardium which is lethal during fetal life. In addition, the heart maintains a well-orchestrated balances in utilizing fatty acids (FAs) and other substrates to meet the high energy requirements. As the master transcriptional regulators of lipid metabolism, RXRs become particularly important for the energy needs of the heart. Accumulating evidence suggested that RXRs may exert direct beneficial effects in the heart both through heterodimerization with other nuclear receptors (NRs) and homodimerization, thus standing as suitable targets for treating in cardiovascular diseases. Although compounds that target RXRs are promising drugs, their use is limited by toxicity. A better understanding of the structural biology of RXRs in cardiovascular disease should enable the rational design of more selective nuclear receptor modulators to overcome these problems. Here, this review summarizes a brief overview of RXRs structure and versatility of RXR action in the control of cardiovascular diseases. And we also discussed the therapeutic potential of RXR ligand.
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Affiliation(s)
- Mingyan Shao
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Linghui Lu
- College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Qian Wang
- State Key Laboratory of Natural and Biomimetic Drugs, School of Pharmaceutical Sciences, Peking University, Beijing, 100191, China
| | - Lin Ma
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Xue Tian
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Changxiang Li
- College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Chun Li
- Modern Research Center of Traditional Chinese Medicine, School of Traditional Chinese Material Medica, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Dongqing Guo
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Qiyan Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China
| | - Wei Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China.
| | - Yong Wang
- School of Life Science, Beijing University of Chinese Medicine, Beijing, 100029, China; College of Traditional Chinese Medicine, Beijing University of Chinese Medicine, Beijing, 100029, China.
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3
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Oncogenic potential of truncated RXRα during colitis-associated colorectal tumorigenesis by promoting IL-6-STAT3 signaling. Nat Commun 2019; 10:1463. [PMID: 30931933 PMCID: PMC6443775 DOI: 10.1038/s41467-019-09375-8] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Accepted: 02/18/2019] [Indexed: 12/22/2022] Open
Abstract
Retinoid X receptor-alpha (RXRα) is a potent regulator of inflammatory responses; however, its therapeutic potential for inflammatory cancer remains to be explored. We previously discovered that RXRα is abnormally cleaved in tumor cells and tissues, producing a truncated RXRα (tRXRα). Here, we show that transgenic expression of tRXRα in mice accelerates the development of colitis-associated colon cancer (CAC). The tumorigenic effect of tRXRα is primarily dependent on its expression in myeloid cells, which results in interleukin-6 (IL-6) induction and STAT3 activation. Mechanistic studies reveal an extensive interaction between tRXRα and TRAF6 in the cytoplasm of macrophages, leading to TRAF6 ubiquitination and subsequent activation of the NF-κB inflammatory pathway. K-80003, a tRXRα modulator derived from nonsteroidal anti-inflammatory drug (NSAID) sulindac, suppresses the growth of tRXRα-mediated colorectal tumor by inhibiting the NF-κB-IL-6-STAT3 signaling cascade. These results provide new insight into tRXRα action and identify a promising tRXRα ligand for treating CAC.
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4
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Chen L, Aleshin AE, Alitongbieke G, Zhou Y, Zhang X, Ye X, Hu M, Ren G, Chen Z, Ma Y, Zhang D, Liu S, Gao W, Cai L, Wu L, Zeng Z, Jiang F, Liu J, Zhou H, Cadwell G, Liddington RC, Su Y, Zhang XK. Modulation of nongenomic activation of PI3K signalling by tetramerization of N-terminally-cleaved RXRα. Nat Commun 2017; 8:16066. [PMID: 28714476 PMCID: PMC5520057 DOI: 10.1038/ncomms16066] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2016] [Accepted: 05/24/2017] [Indexed: 12/14/2022] Open
Abstract
Retinoid X receptor-alpha (RXRα) binds to DNA either as homodimers or heterodimers, but it also forms homotetramers whose function is poorly defined. We previously discovered that an N-terminally-cleaved form of RXRα (tRXRα), produced in tumour cells, activates phosphoinositide 3-kinase (PI3K) signalling by binding to the p85α subunit of PI3K and that K-80003, an anti-cancer agent, inhibits this process. Here, we report through crystallographic and biochemical studies that K-80003 binds to and stabilizes tRXRα tetramers via a ‘three-pronged’ combination of canonical and non-canonical mechanisms. K-80003 binding has no effect on tetramerization of RXRα, owing to the head–tail interaction that is absent in tRXRα. We also identify an LxxLL motif in p85α, which binds to the coactivator-binding groove on tRXRα and dissociates from tRXRα upon tRXRα tetramerization. These results identify conformational selection as the mechanism for inhibiting the nongenomic action of tRXRα and provide molecular insights into the development of RXRα cancer therapeutics. The transcription factor retinoid X receptor-alpha (RXRα) can also form homotetramers. Here the authors show that the anti-cancer agent K-80003 selectively inhibits the nongenomic action of N-terminally-cleaved RXRα in tumour cells by stabilizing its tetramerization but not that of full-length RXRα.
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Affiliation(s)
- Liqun Chen
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China.,College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China.,Sanford Burnham Prebys Medical Discovery Institute, 10901, North Torrey Pines Road, La Jolla, California 92037, USA
| | - Alexander E Aleshin
- Sanford Burnham Prebys Medical Discovery Institute, 10901, North Torrey Pines Road, La Jolla, California 92037, USA
| | - Gulimiran Alitongbieke
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Yuqi Zhou
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Xindao Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Xiaohong Ye
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Mengjie Hu
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Gaoang Ren
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Ziwen Chen
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Yue Ma
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Duo Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Shuai Liu
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Weiwei Gao
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Lijun Cai
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Lingjuan Wu
- College of Biological Science and Engineering, Fuzhou University, Fuzhou 350108, China
| | - Zhiping Zeng
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Fuquan Jiang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Jie Liu
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Hu Zhou
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China
| | - Gregory Cadwell
- Sanford Burnham Prebys Medical Discovery Institute, 10901, North Torrey Pines Road, La Jolla, California 92037, USA
| | - Robert C Liddington
- Sanford Burnham Prebys Medical Discovery Institute, 10901, North Torrey Pines Road, La Jolla, California 92037, USA
| | - Ying Su
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China.,Sanford Burnham Prebys Medical Discovery Institute, 10901, North Torrey Pines Road, La Jolla, California 92037, USA
| | - Xiao-Kun Zhang
- School of Pharmaceutical Sciences, Fujian Provincial Key Laboratory of Innovative Drug Target Research, Xiamen University, Xiamen 361102, China.,Sanford Burnham Prebys Medical Discovery Institute, 10901, North Torrey Pines Road, La Jolla, California 92037, USA
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Carruthers NJ, Parker GC, Gratsch T, Caruso JA, Stemmer PM. Protein Mobility Shifts Contribute to Gel Electrophoresis Liquid Chromatography Analysis. J Biomol Tech 2016; 26:103-12. [PMID: 26229520 DOI: 10.7171/jbt.15-2603-003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Profiling of cellular and subcellular proteomes by liquid chromatography with tandem mass spectrometry (MS) after fractionation by SDS-PAGE is referred to as GeLC (gel electrophoresis liquid chromatography)-MS. The GeLC approach decreases complexity within individual MS analyses by size fractionation with SDS-PAGE. SDS-PAGE is considered an excellent fractionation technique for intact proteins because of good resolution for proteins of all sizes, isoelectric points, and hydrophobicities. Additional information derived from the mobility of the intact proteins is available after an SDS-PAGE fractionation, but that information is usually not incorporated into the proteomic analysis. Any chemical or proteolytic modification of a protein that changes the mobility of that protein in the gel can be detected. The ability of SDS-PAGE to resolve proteins with chemical modifications has not been widely utilized within profiling experiments. In this work, we examined the ability of the GeLC-MS approach to help identify proteins that were modified after a small hairpin RNA-dependent knockdown in an experiment using stable isotope labeling by amino acids in cell culture-based quantitation.
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Affiliation(s)
- Nicholas J Carruthers
- 1 Institute of Environmental Health Sciences and 2 Carman and Ann Adam Department of Pediatrics, Wayne State University, Detroit, Michigan 48201, USA
| | - Graham C Parker
- 1 Institute of Environmental Health Sciences and 2 Carman and Ann Adam Department of Pediatrics, Wayne State University, Detroit, Michigan 48201, USA
| | - Theresa Gratsch
- 1 Institute of Environmental Health Sciences and 2 Carman and Ann Adam Department of Pediatrics, Wayne State University, Detroit, Michigan 48201, USA
| | - Joseph A Caruso
- 1 Institute of Environmental Health Sciences and 2 Carman and Ann Adam Department of Pediatrics, Wayne State University, Detroit, Michigan 48201, USA
| | - Paul M Stemmer
- 1 Institute of Environmental Health Sciences and 2 Carman and Ann Adam Department of Pediatrics, Wayne State University, Detroit, Michigan 48201, USA
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6
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Zhang X, Zhou H, Su Y. Targeting truncated RXRα for cancer therapy. Acta Biochim Biophys Sin (Shanghai) 2016; 48:49-59. [PMID: 26494413 DOI: 10.1093/abbs/gmv104] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/24/2015] [Indexed: 01/08/2023] Open
Abstract
Retinoid X receptor-alpha (RXRα), a unique member of the nuclear receptor superfamily, is a well-established drug target, representing one of the most important targets for pharmacologic interventions and therapeutic applications for cancer. However, how RXRα regulates cancer cell growth and how RXRα modulators suppress tumorigenesis are poorly understood. Altered expression and aberrant function of RXRα are implicated in the development of cancer. Previously, several studies had demonstrated the presence of N-terminally truncated RXRα (tRXRα) proteins resulted from limited proteolysis of RXRα in tumor cells. Recently, we discovered that overexpression of tRXRα can promote tumor growth by interacting with tumor necrosis factor-alpha-induced phosphoinositide 3-kinase and NF-κB signal transduction pathways. We also identified nonsteroidal anti-inflammatory drug Sulindac and analogs as effective inhibitors of tRXRα activities via a unique binding mechanism. This review discusses the emerging roles of tRXRα and modulators in the regulation of cancer cell survival and death as well as inflammation and our recent understanding of tRXRα regulation by targeting the alternate binding sites on its surface.
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Affiliation(s)
- Xiaokun Zhang
- School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China Sanford Burnham Prebys Medical Discovery Institute, Cancer Center, La Jolla, CA 92037, USA
| | - Hu Zhou
- School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Ying Su
- School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China Sanford Burnham Prebys Medical Discovery Institute, Cancer Center, La Jolla, CA 92037, USA
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7
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Chen F, Chen J, Lin J, Cheltsov AV, Xu L, Chen Y, Zeng Z, Chen L, Huang M, Hu M, Ye X, Zhou Y, Wang G, Su Y, Zhang L, Zhou F, Zhang XK, Zhou H. NSC-640358 acts as RXRα ligand to promote TNFα-mediated apoptosis of cancer cell. Protein Cell 2015; 6:654-666. [PMID: 26156677 PMCID: PMC4537469 DOI: 10.1007/s13238-015-0178-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2015] [Accepted: 05/03/2015] [Indexed: 12/18/2022] Open
Abstract
Retinoid X receptor α (RXRα) and its N-terminally truncated version tRXRα play important roles in tumorigenesis, while some RXRα ligands possess potent anti-cancer activities by targeting and modulating the tumorigenic effects of RXRα and tRXRα. Here we describe NSC-640358 (N-6), a thiazolyl-pyrazole derived compound, acts as a selective RXRα ligand to promote TNFα-mediated apoptosis of cancer cell. N-6 binds to RXRα and inhibits the transactivation of RXRα homodimer and RXRα/TR3 heterodimer. Using mutational analysis and computational study, we determine that Arg316 in RXRα, essential for 9-cis-retinoic acid binding and activating RXRα transactivation, is not required for antagonist effects of N-6, whereas Trp305 and Phe313 are crucial for N-6 binding to RXRα by forming extra π–π stacking interactions with N-6, indicating a distinct RXRα binding mode of N-6. N-6 inhibits TR3-stimulated transactivation of Gal4-DBD-RXRα-LBD by binding to the ligand binding pocket of RXRα-LBD, suggesting a strategy to regulate TR3 activity indirectly by using small molecules to target its interacting partner RXRα. For its physiological activities, we show that N-6 strongly inhibits tumor necrosis factor α (TNFα)-induced AKT activation and stimulates TNFα-mediated apoptosis in cancer cells in an RXRα/tRXRα dependent manner. The inhibition of TNFα-induced tRXRα/p85α complex formation by N-6 implies that N-6 targets tRXRα to inhibit TNFα-induced AKT activation and to induce cancer cell apoptosis. Together, our data illustrate a new RXRα ligand with a unique RXRα binding mode and the abilities to regulate TR3 activity indirectly and to induce TNFα-mediated cancer cell apoptosis by targeting RXRα/tRXRα.
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Affiliation(s)
- Fan Chen
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
- />School of Biological Science and Biotechnology, Minnan Normal University, Zhangzhou, 363000 China
| | - Jiebo Chen
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Jiacheng Lin
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | | | - Lin Xu
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Ya Chen
- />Cancer Center, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037 USA
| | - Zhiping Zeng
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Liqun Chen
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Mingfeng Huang
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Mengjie Hu
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Xiaohong Ye
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Yuqi Zhou
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Guanghui Wang
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
| | - Ying Su
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
- />Cancer Center, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037 USA
| | - Long Zhang
- />Life Science Institute, Zhejiang University, Hangzhou, 310058 China
| | - Fangfang Zhou
- />Institutes of Biology and Medical Sciences, Soochow University, Suzhou, 215123 China
| | - Xiao-kun Zhang
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
- />Cancer Center, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037 USA
| | - Hu Zhou
- />School of Pharmaceutical Sciences, Xiamen University, Xiamen, 361102 China
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8
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Zhang XK, Su Y, Chen L, Chen F, Liu J, Zhou H. Regulation of the nongenomic actions of retinoid X receptor-α by targeting the coregulator-binding sites. Acta Pharmacol Sin 2015; 36:102-12. [PMID: 25434990 DOI: 10.1038/aps.2014.109] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Accepted: 09/28/2014] [Indexed: 12/31/2022] Open
Abstract
Retinoid X receptor-α (RXRα), a unique member of the nuclear receptor superfamily, represents an intriguing and unusual target for pharmacologic interventions and therapeutic applications in cancer, metabolic disorders and neurodegenerative diseases. Despite the fact that the RXR-based drug Targretin (bexarotene) is currently used for treating human cutaneous T-cell lymphoma and the fact that RXRα ligands (rexinoids) show beneficial effects in the treatment of cancer and diseases, the therapeutic potential of RXRα remains unexplored. In addition to its conventional transcription regulation activity in the nucleus, RXRα can act in the cytoplasm to modulate important biological processes, such as mitochondria-dependent apoptosis, inflammation, and phosphatidylinositol 3-kinase (PI3K)/AKT-mediated cell survival. Recently, new small-molecule-binding sites on the surface of RXRα have been identified, which mediate the regulation of the nongenomic actions of RXRα by a class of small molecules derived from the nonsteroidal anti-inflammatory drug (NSAID) Sulindac. This review discusses the emerging roles of the nongenomic actions of RXRα in the RXRα signaling network, and their possible implications in cancer, metabolic and neurodegenerative disorders, as well as our current understanding of RXRα regulation by targeting alternate binding sites on its surface.
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9
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Harvatine KJ, Boisclair YR, Bauman DE. Liver x receptors stimulate lipogenesis in bovine mammary epithelial cell culture but do not appear to be involved in diet-induced milk fat depression in cows. Physiol Rep 2014; 2:e00266. [PMID: 24760520 PMCID: PMC4002246 DOI: 10.1002/phy2.266] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Abstract Milk fat synthesis of ruminants can be inhibited by intermediates of ruminal fatty acid biohydrogenation including trans-10, cis-12 conjugated linoleic acid (CLA). These biohydrogenation intermediates signal a coordinated downregulation of genes involved in mammary FA synthesis, transport, and esterification. We have previously reported decreased mammary expression of sterol response element-binding protein 1 (SREBP1), SREBP1-activating proteins, and thyroid hormone-responsive spot 14 (S14) in the cow during diet-induced milk fat depression (MFD), and treatment with trans-10, cis-12 CLA. Liver x receptors (LXR) and retinoid x receptors (RXR) regulate lipogenesis and are known to bind polyunsaturated FA and LXR agonist increases lipid synthesis in mammary epithelial cell culture. The current studies investigated if biohydrogenation products of rumen origin inhibit mammary lipogenesis through LXR and/or RXR. Expression of LXRs was not different in lactating compared to nonlactating bovine mammary tissue, and expression of LXRs, RXRα, and selected LXR and RXR target genes was not changed in mammary tissue during diet-induced or CLA-induced MFD in the cow. In bovine mammary epithelial cell culture, LXR agonist stimulated lipogenesis and expression of LXRß, ATP-binding cassette 1 (ABCA1), SREBP1c, and S14, but LXR activation did not overcome CLA inhibition of lipogenesis and downregulation of LXRß, SREBP1c, and S14 expression. Lastly, expression of the LXR-regulated carbohydrate-responsive element-binding protein (ChREBP) was higher in lactating than nonlactating tissue and was decreased during CLA-induced MFD. We conclude that changes in mammary LXR expression in dairy cows are not involved in MFD and that trans-10, cis-12 CLA inhibition of lipogenesis and diet-induced MFD appears independent of direct LXR signaling.
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Affiliation(s)
- Kevin J Harvatine
- Department of Animal Science, Penn State University, University Park, Pennsylvania
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10
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Wang GH, Jiang FQ, Duan YH, Zeng ZP, Chen F, Dai Y, Chen JB, Liu JX, Liu J, Zhou H, Chen HF, Zeng JZ, Su Y, Yao XS, Zhang XK. Targeting truncated retinoid X receptor-α by CF31 induces TNF-α-dependent apoptosis. Cancer Res 2012; 73:307-18. [PMID: 23151904 DOI: 10.1158/0008-5472.can-12-2038] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
A truncated version of retinoid X receptor-α, tRXR-α, promotes cancer cell survival by activating the phosphoinositide 3-kinase (PI3K)/AKT pathway. However, targeting the tRXR-α-mediated survival pathway for cancer treatment remains to be explored. We report here our identification of a new natural product molecule, CF31, a xanthone isolated from Cratoxylum formosum ssp. pruniflorum, and the biologic evaluation of its regulation of the tRXR-α-mediated PI3K/AKT pathway. CF31 binds RXR-α and its binding results in inhibition of RXR-α transactivation. Through RXR-α mutational analysis and computational studies, we show that Arg316 of RXR-α, known to form salt bridges with certain RXR-α ligands, such as 9-cis-retinoic acid (9-cis-RA), is not required for the antagonist effect of CF31, showing a distinct binding mode. Evaluation of several CF31 analogs suggests that the antagonist effect is mainly attributed to an interference with Leu451 of helix H12 in RXR-α. CF31 is a potent inhibitor of AKT activation in various cancer cell lines. When combined with TNF-α, it suppresses TNF-α activation of AKT by inhibiting TNF-α-induced tRXR-α interaction with the p85α regulatory subunit of PI3K. CF31 inhibition of TNF-α activation of AKT also results in TNF-α-dependent activation of caspase-8 and apoptosis. Together, our results show that CF31 is an effective converter of TNF-α signaling from survival to death by targeting tRXR-α in a unique mode and suggest that identification of a natural product that targets an RXR-mediated cell survival pathway that regulates PI3K/AKT may offer a new therapeutic strategy to kill cancer cells.
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Affiliation(s)
- Guang-Hui Wang
- School of Pharmaceutical Science, Xiamen University, Xiamen, China
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11
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Lu N, Liu J, Liu J, Zhang C, Jiang F, Wu H, Chen L, Zeng W, Cao X, Yan T, Wang G, Zhou H, Lin B, Yan X, Zhang XK, Zeng JZ. Antagonist effect of triptolide on AKT activation by truncated retinoid X receptor-alpha. PLoS One 2012; 7:e35722. [PMID: 22545132 PMCID: PMC3335786 DOI: 10.1371/journal.pone.0035722] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2011] [Accepted: 03/20/2012] [Indexed: 11/18/2022] Open
Abstract
Background Retinoid X receptor-alpha (RXRα) is a key member of the nuclear receptor superfamily. We recently demonstrated that proteolytic cleavage of RXRα resulted in production of a truncated product, tRXRα, which promotes cancer cell survival by activating phosphatidylinositol-3-OH kinase (PI3K)/AKT pathway. However, how the tRXRα-mediated signaling pathway in cancer cells is regulated remains elusive. Methodology/Principal Findings We screened a natural product library for tRXRα targeting leads and identified that triptolide, an active component isolated from traditional Chinese herb Trypterygium wilfordii Hook F, could modulate tRXRα-mediated cancer cell survival pathway in vitro and in animals. Our results reveal that triptolide strongly induces cancer cell apoptosis dependent on intracellular tRXRα expression levels, demonstrating that tRXRα serves as an important intracellular target of triptolide. We show that triptolide selectively induces tRXRα degradation and inhibits tRXRα-dependent AKT activity without affecting the full-length RXRα. Interestingly, such effects of triptolide are due to its activation of p38. Although triptolide also activates Erk1/2 and MAPK pathways, the effects of triptolide on tRXRα degradation and AKT activity are only reversed by p38 siRNA and p38 inhibitor. In addition, the p38 inhibitor potently inhibits tRXRα interaction with p85α leading to AKT inactivation. Our results demonstrate an interesting novel signaling interplay between p38 and AKT through tRXRα mediation. We finally show that targeting tRXRα by triptolide strongly activates TNFα death signaling and enhances the anticancer activity of other chemotherapies Conclusions/Significance Our results identify triptolide as a new xenobiotic regulator of the tRXRα-dependent survival pathway and provide new insight into the mechanism by which triptolide acts to induce apoptosis of cancer cells. Triptolide represents one of the most promising therapeutic leads of natural products of traditional Chinese medicine with unfortunate side-effects. Our findings will offer new strategies to develop improved triptolide analogs for cancer therapy.
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Affiliation(s)
- Na Lu
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Jinxing Liu
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Jie Liu
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Chunyun Zhang
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Fuquan Jiang
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Hua Wu
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Liqun Chen
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Wenjun Zeng
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Xihua Cao
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Tingdong Yan
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Guanghui Wang
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Hu Zhou
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Bingzhen Lin
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
| | - Xiaomei Yan
- The Key Laboratory of Analytical Science, The Key Laboratory for Chemical Biology of Fujian Province, Department of Chemical Biology, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xiao-kun Zhang
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
- Cancer Center, Sanford-Burnham Medical Research Institute, La Jolla, California, United States of America
- * E-mail: (JZ); (XK)
| | - Jin-Zhang Zeng
- School of Pharmaceutical Sciences and Institute for Biomedical Research, Xiamen University, Xiamen, China
- * E-mail: (JZ); (XK)
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12
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Kido H, Ishidoh K. Nobuhiko Katunuma: an outstanding scientist in the field of proteolysis and warm-hearted 'Kendo Fighter' biochemist. J Biochem 2011; 148:527-31. [PMID: 20980477 DOI: 10.1093/jb/mvq109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Professor Nobuhiko Katunuma is well known for his outstanding contribution to the understanding of proteolysis in general and cysteine proteinases and their inhibitors in mammals. In fact, he is a world pioneer in the field. In 1963, he started his highly successful scientific career as a Professor at the Institute for Enzyme Research, the University of Tokushima. During the initial 30 years of his career, he was interested in vitamin B6 metabolism and discovered the acceleration of turnover rates of pyridoxal enzyme in apoprotein formation. After this period, his interest expanded to lysosomal cystein proteinases and their endogenous inhibitors. After determining the crystal structure of human cathepsin B, he generated a series of chemically synthesized specific inhibitors of cathepsins. These inhibitors are currently used throughout the world and some of them have been applied therapeutically in various diseases. During his career and even at present, Professor Katunuma has been studying Biochemistry in Medicine and also practicing to become a 'Kendo sword fencing Fighter'.
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Affiliation(s)
- Hiroshi Kido
- Division of Enzyme Chemistry, Institute for Enzyme Research, The University of Tokushima, Kuramotocho 3-18-15, Tokushima 770-8503, Japan.
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13
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Zhou H, Liu W, Su Y, Wei Z, Liu J, Kolluri SK, Wu H, Cao Y, Chen J, Wu Y, Yan T, Cao X, Gao W, Molotkov A, Jiang F, Li WG, Lin B, Zhang HP, Yu J, Luo SP, Zeng JZ, Duester G, Huang PQ, Zhang XK. NSAID sulindac and its analog bind RXRalpha and inhibit RXRalpha-dependent AKT signaling. Cancer Cell 2010; 17:560-73. [PMID: 20541701 PMCID: PMC2907921 DOI: 10.1016/j.ccr.2010.04.023] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/03/2009] [Revised: 02/21/2010] [Accepted: 04/20/2010] [Indexed: 10/19/2022]
Abstract
Nonsteroidal anti-inflammatory drugs (NSAIDs) exert their anticancer effects through cyclooxygenase-2 (COX-2)-dependent and independent mechanisms. Here, we report that Sulindac, an NSAID, induces apoptosis by binding to retinoid X receptor-alpha (RXRalpha). We identified an N-terminally truncated RXRalpha (tRXRalpha) in several cancer cell lines and primary tumors, which interacted with the p85alpha subunit of phosphatidylinositol-3-OH kinase (PI3K). Tumor necrosis factor-alpha (TNFalpha) promoted tRXRalpha interaction with the p85alpha, activating PI3K/AKT signaling. When combined with TNFalpha, Sulindac inhibited TNFalpha-induced tRXRalpha/p85alpha interaction, leading to activation of the death receptor-mediated apoptotic pathway. We designed and synthesized a Sulindac analog K-80003, which has increased affinity to RXRalpha but lacks COX inhibitory activity. K-80003 displayed enhanced efficacy in inhibiting tRXRalpha-dependent AKT activation and tRXRalpha tumor growth in animals.
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Affiliation(s)
- Hu Zhou
- Institute for Biomedical Research, Xiamen University, Xiamen, China
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Wen Liu
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Ying Su
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Zhen Wei
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Jie Liu
- Institute for Biomedical Research, Xiamen University, Xiamen, China
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Siva Kumar Kolluri
- Department of Environmental and Molecular Toxicology, Oregon State University, Corvallis, OR, USA
| | - Hua Wu
- Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Yu Cao
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Jiebo Chen
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Yin Wu
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Tingdong Yan
- Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Xihua Cao
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Weiwei Gao
- Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Andrei Molotkov
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Fuquan Jiang
- Institute for Biomedical Research, Xiamen University, Xiamen, China
| | | | - Bingzhen Lin
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | | | - Jinghua Yu
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Shi-Peng Luo
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Jin-zhang Zeng
- Institute for Biomedical Research, Xiamen University, Xiamen, China
| | - Gregg Duester
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
| | - Pei-Qiang Huang
- College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
| | - Xiao-kun Zhang
- Institute for Biomedical Research, Xiamen University, Xiamen, China
- Sanford-Burnham Medical Research Institute, La Jolla, CA, USA
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14
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Han YH, Zhou H, Kim JH, Yan TD, Lee KH, Wu H, Lin F, Lu N, Liu J, Zeng JZ, Zhang XK. A unique cytoplasmic localization of retinoic acid receptor-gamma and its regulations. J Biol Chem 2009; 284:18503-14. [PMID: 19416983 PMCID: PMC2709335 DOI: 10.1074/jbc.m109.007708] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 04/13/2009] [Indexed: 11/06/2022] Open
Abstract
Recent evidence suggests that extranuclear action of retinoid receptors is involved in mediating the pleiotropic effects of retinoids. However, whether they reside in the cytoplasm remains elusive. Here, we showed that retinoic acid receptor-gamma (RARgamma) was cytoplasmic in confluent cells, or when cells were released from serum depletion or treated with growth factors. In studying the regulation of RARgamma subcellular localization, we observed that ectopically overexpressed RARgamma was mainly cytoplasmic irrespective of serum concentration and cell density. The cytoplasmic retention of RARgamma was inhibited by ligand retinoic acid (RA). In addition, coexpression of retinoid X receptor-alpha (RXRalpha) resulted in nuclear localization of RARgamma through their heterodimerization. Mutagenesis studies revealed that a C-terminal fragment of RXRalpha potently prevents RA-induced RARgamma nuclear localization and transcriptional function. Furthermore, our results showed that the cytoplasmic retention of RARgamma was due to the presence of its unique N-terminal A/B domain, which was subject to regulation by p38 MAPK-mediated phosphorylation. Deletion or mutation of the N-terminal A/B domain largely impaired its cytoplasmic localization. Together, our data demonstrate that the subcellular localization of RARgamma is regulated by complex interactions among ligand binding, receptor phosphorylation, and receptor dimerizations.
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Affiliation(s)
- Young-Hoon Han
- From The Burnham Institute for Medical Research, Cancer Center, La Jolla, California 92037
- the Divsion of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea, and
| | - Hu Zhou
- From The Burnham Institute for Medical Research, Cancer Center, La Jolla, California 92037
| | - Jin-Hee Kim
- the Divsion of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea, and
| | - Ting-dong Yan
- the Institute for Biomedical Research, Xiamen University, Xiamen 361005, China
| | - Kee-Ho Lee
- the Divsion of Radiation Cancer Research, Korea Institute of Radiological and Medical Sciences, Seoul 139-706, Korea, and
| | - Hua Wu
- the Institute for Biomedical Research, Xiamen University, Xiamen 361005, China
| | - Feng Lin
- From The Burnham Institute for Medical Research, Cancer Center, La Jolla, California 92037
| | - Na Lu
- the Institute for Biomedical Research, Xiamen University, Xiamen 361005, China
| | - Jie Liu
- From The Burnham Institute for Medical Research, Cancer Center, La Jolla, California 92037
- the Institute for Biomedical Research, Xiamen University, Xiamen 361005, China
| | - Jin-zhang Zeng
- the Institute for Biomedical Research, Xiamen University, Xiamen 361005, China
| | - Xiao-kun Zhang
- From The Burnham Institute for Medical Research, Cancer Center, La Jolla, California 92037
- the Institute for Biomedical Research, Xiamen University, Xiamen 361005, China
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15
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Ventura-Holman T, Mamoon A, Maher JF, Subauste JS. Thyroid hormone responsive genes in the murine hepatocyte cell line AML 12. Gene 2007; 396:332-7. [PMID: 17532580 DOI: 10.1016/j.gene.2007.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2007] [Revised: 04/04/2007] [Accepted: 04/05/2007] [Indexed: 11/29/2022]
Abstract
Thyroid hormone (T3) plays an important role in gene regulation in the liver. Previous studies have been done in complex systems such as animal models, or in transformed malignant hepatic cell lines in which thyroid hormone receptor (TR) was over-expressed by co-transfection. Therefore, the aim of this study was to characterize T3-responsive genes in a simple system, by using a non-transformed hepatic cell line that is able to express sufficient amounts of endogenous TRs. For this purpose we used the murine non-transformed hepatocyte cell line AML 12. We performed analyses using a cDNA microarray containing 15,000 murine genes. We found 12 genes to be up-regulated and 5 genes to be down-regulated in the presence of T3. For some of the genes not previously known to be regulated by T3, we confirmed the regulation by T3 using real-time PCR. Our data in AML 12 cells provide a simple and physiologically relevant system to study T3 action, without the influence of neoplastic transformation or artificial TR over-expression. Furthermore, our data describe novel T3 responsive genes and provide insight into the role of T3 in important processes such as cholesterol metabolism, bile acid secretion, oncogenesis, among others, that can be tested in future experiments in vivo.
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Affiliation(s)
- Tereza Ventura-Holman
- Department of Medicine, University of Mississippi Medical Center, Jackson, MS 39216, USA
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16
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Kim YJ, Sapp E, Cuiffo BG, Sobin L, Yoder J, Kegel KB, Qin ZH, Detloff P, Aronin N, DiFiglia M. Lysosomal proteases are involved in generation of N-terminal huntingtin fragments. Neurobiol Dis 2006; 22:346-56. [PMID: 16423528 DOI: 10.1016/j.nbd.2005.11.012] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2005] [Revised: 11/18/2005] [Accepted: 11/24/2005] [Indexed: 11/20/2022] Open
Abstract
N-terminal mutant huntingtin (N-mhtt) fragments form inclusions and cause cell death in vitro. Mutant htt expression stimulates autophagy and increases levels of lysosomal proteases. Here, we show that lysosomal proteases, cathepsins D, B and L, affected mhtt processing and levels of cleavage products (cp) known as A and B, which form inclusions. Adding inhibitors of cathepsin D, B and L to clonal striatal cells reduced mhtt, especially mhtt fragment cp A. Mutant htt fully degraded in cathepsin-L-treated lysates but formed stable N-mhtt fragments upon exposure to cathepsin D. Mutagenesis analysis of htt cDNA suggested that cathepsin D and the protease for cp A may cleave htt in the same region. Brain lysates from HD knock-in mice expressed N-mhtt fragments that accumulated with cathepsin D treatment and declined with aspartyl protease inhibition. Findings implicate lysosomal proteases in formation of N-mhtt fragments and clearance of mhtt.
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Affiliation(s)
- Yun J Kim
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA
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17
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Katunuma N, Ohashi A, Sano E, Murata E, Shiota H, Yamamoto K, Majima E, Le QT. New cysteine protease inhibitors in physiological secretory fluids and their medical significance. ADVANCES IN ENZYME REGULATION 2004; 43:393-410. [PMID: 12791399 DOI: 10.1016/s0065-2571(02)00041-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- N Katunuma
- Institute for Health Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima City, Tokushima 770-8514, Japan.
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18
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Casas F, Daury L, Grandemange S, Busson M, Seyer P, Hatier R, Carazo A, Cabello G, Wrutniak-Cabello C. Endocrine regulation of mitochondrial activity: involvement of truncated RXRalpha and c-Erb Aalpha1 proteins. FASEB J 2003; 17:426-36. [PMID: 12631582 DOI: 10.1096/fj.02-0732com] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The importance of mitochondrial activity has recently been extended to the regulation of developmental processes. Numerous pathologies associated with organelle's dysfunctions emphasize their physiological importance. However, regulation of mitochondrial genome transcription, a key element for organelle's function, remains poorly understood. After characterization in the organelle of a truncated form of the triiodothyronine nuclear receptor (p43), a T3-dependent transcription factor of the mitochondrial genome, our purpose was to search for other mitochondrial receptors involved in the regulation of organelle transcription. We show that a 44 kDa protein related to RXRalpha (mt-RXR), another nuclear receptor, is located in the mitochondrial matrix. We found that mt-RXR is produced after cytosolic or intramitochondrial enzymatic cleavage of the RXRalpha nuclear receptor. After mitochondrial import and binding to specific sequences of the organelle genome, mt-RXR induces a ligand-dependent increase in mitochondrial RNA levels. mt-RXR physically interacts with p43 and acts alone or through a heterodimerical complex activated by 9-cis-retinoic acid and T3 to increase RNA levels. These data indicate that hormonal regulation of mitochondrial transcription occurs through pathways similar to those that take place in the nucleus and open a new way to better understand hormone and vitamin action at the cellular level.
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MESH Headings
- Alitretinoin
- Animals
- Binding Sites
- Calpain/metabolism
- DNA, Mitochondrial/chemistry
- DNA, Mitochondrial/genetics
- DNA, Mitochondrial/metabolism
- Genome
- Ligands
- Male
- Mitochondria/genetics
- Mitochondria, Liver/genetics
- Mitochondria, Liver/metabolism
- Mitochondria, Liver/ultrastructure
- Models, Biological
- Protein Transport
- RNA/biosynthesis
- RNA, Mitochondrial
- Rats
- Rats, Wistar
- Receptors, Retinoic Acid/chemistry
- Receptors, Retinoic Acid/metabolism
- Receptors, Retinoic Acid/physiology
- Retinoid X Receptors
- Thyroid Hormone Receptors alpha/chemistry
- Thyroid Hormone Receptors alpha/physiology
- Transcription Factors/chemistry
- Transcription Factors/metabolism
- Transcription Factors/physiology
- Transcription, Genetic
- Tretinoin/pharmacology
- Triiodothyronine/pharmacology
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Affiliation(s)
- François Casas
- UMR-866 Différenciation Cellulaire et Croissance (INRA-UMII-ENSAM), Unité d'Endocrinologie Cellulaire, Institut National de la Recherche Agronomique (INRA), 34060 Montpellier Cedex 1, France
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19
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Kato M, Nagaya T, Fujieda M, Saito K, Yoshida J, Seo H. Expression of PPARgamma and its ligand-dependent growth inhibition in human brain tumor cell lines. Jpn J Cancer Res 2002; 93:660-6. [PMID: 12079514 PMCID: PMC5927044 DOI: 10.1111/j.1349-7006.2002.tb01304.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Peroxisome proliferator-activated receptor gamma (PPARgamma) belongs to a superfamily of thyroid / steroid hormone receptors and regulates transcription of their target genes in a ligand-dependent manner. Recently, PPARgamma was reported to be expressed in several cell lines derived from breast, colon, stomach and lung cancers. Activation of PPARgamma by its ligand inhibits the growth of these tumor cells, suggesting that PPARgamma ligand is a potential anti-cancer agent in PPARgamma-expressing tumors. However, its expression in brain tumors has not been studied. We thus studied the expression in glioma samples with different pathological stages from 20 patients. It was demonstrated that 95% of the glioma tissue expressed PPARgamma mRNA. The results prompted us to study whether PPARgamma ligand affects the growth of cell lines derived from brain tumors. The receptor expression was studied in 9 cell lines either derived from malignant glioma or neuroblastoma. The expression was detected in a glioma cell line SK-MG-1 and in a neuroblastoma cell line NB-1. Addition of one of the PPARgamma ligands, troglitazone, induced growth inhibition in both cell lines. Further analyses revealed that this growth inhibition is caused by a PPARgamma-mediated induction of apoptosis. These results suggest that PPARgamma ligands could be a potential therapeutic agent for the treatment of the brain tumors expressing this receptor.
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Affiliation(s)
- Mihoko Kato
- Department of Endocrinology and Metabolism, Division of Molecular and Cellular Adaptation, Research Institute of Environmental Medicine, Nagoya University, Chikusa-ku, Nagoya 464-8601
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20
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Shibata A, Nagaya T, Imai T, Funahashi H, Nakao A, Seo H. Inhibition of NF-kappaB activity decreases the VEGF mRNA expression in MDA-MB-231 breast cancer cells. Breast Cancer Res Treat 2002; 73:237-43. [PMID: 12160329 DOI: 10.1023/a:1015872531675] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
VEGF (vascular endothelial growth factor) secreted from tumor cells including breast cancer serves as a potent angiogenic factor which favors tumor growth and metastasis. Indeed, a higher concentration of serum VEGF has been shown to associate with a poorer prognosis in patients with breast cancer. On the other hand, constitutive expression of a transcription factor, NF-kappaB was correlated with progression and metastasis in a number of human breast cancers, suggesting a possible regulation of VEGF expression by NF-kappaB. We thus investigated the relationship between the expression of VEGF and constitutive NF-kappaB activity in three breast cancer cell lines, MCF-7, T47D, and MDA-MB-231. The basal levels of VEGF mRNA expression correlated with those of nuclear NF-kappaB activity in these cell lines. The highest NF-KB activity in MDA-MB-231 cells was associated with the highest expression of VEGF mRNA, while the activity and the mRNA levels were moderate in MCF cells and the lowest in T47D cells. In MDA-MB-231 cells, inhibition of NF-KB by adenovirus-mediated expression of a dominant negative NF-kappaB or by a proteasome inhibitor, MG132, decreased the VEGF mRNA. These results suggest that NF-kappaB is involved in the upregulation of VEGF mRNA and inhibition of the activity could be a new approach for the treatment of breast cancer by preventing angiogenesis.
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Affiliation(s)
- Arihiro Shibata
- Department of Endocrinology and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Japan
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21
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Irving JA, Shushanov SS, Pike RN, Popova EY, Brömme D, Coetzer THT, Bottomley SP, Boulynko IA, Grigoryev SA, Whisstock JC. Inhibitory activity of a heterochromatin-associated serpin (MENT) against papain-like cysteine proteinases affects chromatin structure and blocks cell proliferation. J Biol Chem 2002; 277:13192-201. [PMID: 11821386 DOI: 10.1074/jbc.m108460200] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
MENT (Myeloid and Erythroid Nuclear Termination stage-specific protein) is a developmentally regulated chromosomal serpin that condenses chromatin in terminally differentiated avian blood cells. We show that MENT is an effective inhibitor of the papain-like cysteine proteinases cathepsins L and V. In addition, ectopic expression of MENT in mammalian cells is apparently sufficient to inhibit a nuclear papain-like cysteine proteinase and prevent degradation of the retinoblastoma protein, a major regulator of cell proliferation. MENT also accumulates in the nucleus, causes a strong block in proliferation, and promotes condensation of chromatin. Variants of MENT with mutations or deletions within the M-loop, which contains a nuclear localization signal and an AT-hook motif, reveal that this region mediates nuclear transport and morphological changes associated with chromatin condensation. Non-inhibitory mutants of MENT were constructed to determine whether its inhibitory activity has a role in blocking proliferation. These mutations changed the mode of association with chromatin and relieved the block in proliferation, without preventing transport to the nucleus. We conclude that the repressive effect of MENT on chromatin is mediated by its direct interaction with a nuclear protein that has a papain-like cysteine proteinase active site.
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Affiliation(s)
- James A Irving
- Department of Biochemistry and Molecular Biology, Clayton Campus, Monash University, P. O. Box 13D, Victoria 3800, Australia
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22
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Haberkorn V, Heydel JM, Mounie J, Artur Y, Goudonnet H. Influence of vitamin A status on the regulation of uridine (5'-)diphosphate-glucuronosyltransferase (UGT) 1A1 and UGT1A6 expression by L-triiodothyronine. Br J Nutr 2001; 85:289-97. [PMID: 11299074 DOI: 10.1079/bjn2000243] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The uridine (5'-)diphosphate-glucuronosyltransferases (UGT) are involved in the phase II of various xenobiotics and endogenous compounds. They are responsible for glucuronidation of many substrates, especially including bilirubin (UGT1A1) and phenolic compounds (UGT1A6). We previously showed that the expression of both isoforms is regulated at the transcriptional level by thyroid hormone in rat liver. In this present study, effects of vitamin A dietary intake (0, 1.72, 69 microg retinol acetate/g food) on the regulation of UGT1A1 and UGT1A6 activity and expression by 3,5,3' triiodo-l-thyronine (l-T3) were examined in the same organ. Activities were determined toward bilirubin and 4-nitrophenol. UGT mRNA were analysed by reverse transcription and amplification methods (reverse transcription-polymerase chain reaction) and quantified by capillary electrophoresis. In rats fed a vitamin A-balanced diet, a single injection of l-T3 (500 microg/kg body weight) increased UGT1A6 mRNA expression whereas this hormone decreased UGT1A1 mRNA expression. In addition we observed that the specific effect of l-T3 on UGT1A1 and UGT1A6 was reduced in animals receiving a vitamin A-enriched diet and disappeared in those fed a vitamin A-free diet. The modulations observed in mRNA expression are concomitant with those found for UGT activities. Our results demonstrate for the first time the existence of a strong interaction between vitamin A and thyroid hormone on the regulation of genes encoding cellular detoxification enzymes, in this case the UGT.
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Affiliation(s)
- V Haberkorn
- Unité de Biochimie-Pharmacologie-Toxicologie, Université de Bourgogne, 7 bd Jeanne d'Arc, BP 87900-21079, Dijon Cédex, France
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Moriyama T, Wada M, Urade R, Kito M, Katunuma N, Ogawa T, Simoni RD. 3-Hydroxy-3-methylglutaryl Coenzyme A Reductase Is Sterol-Dependently Cleaved by Cathepsin L-Type Cysteine Protease in the Isolated Endoplasmic Reticulum. Arch Biochem Biophys 2001; 386:205-12. [PMID: 11368343 DOI: 10.1006/abbi.2000.2209] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have recently shown that 3-hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase, an endoplasmic reticulum (ER) membrane protein, is degraded in ER membranes prepared from sterol pretreated cells and that such degradation is catalyzed by a cysteine protease within the reductase membrane domain. The use of various protease inhibitors suggested that degradation of HMG-CoA reductase in vitro is catalyzed by a cathepsin L-type cysteine protease. Purified ER contains E-64-sensitive cathepsin L activity whose inhibitor sensitivity was well matched to that of HMG-CoA reductase degradation in vitro. CLIK-148 (cathepsin L inhibitor) inhibited degradation of HMG-CoA reductase in vitro. Purified cathepsin L also efficiently cleaved HMG-CoA reductase in isolated ER preparations. To determine whether a cathepsin L-type cysteine protease is involved in sterol-regulated degradation of HMG-CoA reductase in vivo, we examined the effect of E-64d, a membrane-permeable cysteine protease inhibitor, in living cells. While lactacystin, a proteasome-specific inhibitor, inhibited sterol-dependent degradation of HMG-CoA reductase, E-64d failed to do so. In contrast, degradation of HMG-CoA reductase in sonicated cells was inhibited by E-64d, CLIK-148, and leupeptin but not by lactacystin. Our results indicate that HMG-CoA reductase is degraded by the proteasome under normal conditions in living cells and that it is cleaved by cathepsin L leaked from lysosomes during preparation of the ER, thus clarifying the apparently paradoxical in vivo and in vitro results. Cathepsin L-dependent proteolysis was observed to occur preferentially in sterol-pretreated cells, suggesting that sterol treatment results in conformational changes in HMG-CoA reductase that make it more susceptible to such cleavage.
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Affiliation(s)
- T Moriyama
- Research Institute for Food Science, Kyoto University, Gokasho, Japan.
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Nagaya T, Fujieda M, Otsuka G, Yang JP, Okamoto T, Seo H. A potential role of activated NF-kappa B in the pathogenesis of euthyroid sick syndrome. J Clin Invest 2000; 106:393-402. [PMID: 10930442 PMCID: PMC314321 DOI: 10.1172/jci7771] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/1999] [Accepted: 06/19/2000] [Indexed: 12/29/2022] Open
Abstract
Euthyroid sick syndrome, characterized by low serum 3,5, 3'-triiodothyronine (T(3)) with normal L-thyroxine levels, is associated with a wide variety of disorders including sepsis, malignancy, and AIDS. The degree of low T(3) in circulation has been shown to correlate with the severity of the underlying disorders and with the prognosis. Elevated TNF-alpha levels, which accompany severe illness, are associated with decreased activity of type I 5'-deiodinase (5'-DI) in liver, leading us to speculate that high levels of this factor contribute to euthyroid sick syndrome. Here we demonstrate that the activation of NF-kappa B by TNF-alpha interferes with thyroid-hormone action as demonstrated by impairment of T(3)-dependent induction of 5'-DI gene expression in HepG2 cells. Inhibition of NF-kappa B action by a dominant-negative NF-kappa B reversed this effect and allowed T(3) induction of 5'-DI. Furthermore, we show that an inhibitor of NF-kappa B activation, clarithromycin (CAM), can inhibit TNF-alpha-induced activation of NF-kappa B and restore T(3)-dependent induction of 5'-DI mRNA and enzyme activity. These results suggest that NF-kappa B activation by TNF-alpha is involved in the pathogenesis of euthyroid sick syndrome and that CAM could help prevent a decrease in serum T(3) levels and thus ameliorate euthyroid sick syndrome.
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Affiliation(s)
- T Nagaya
- Department of Endocrinology and Metabolism, Division of Molecular and Cellular Adaptation, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
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25
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Guncar G, Klemencic I, Turk B, Turk V, Karaoglanovic-Carmona A, Juliano L, Turk D. Crystal structure of cathepsin X: a flip-flop of the ring of His23 allows carboxy-monopeptidase and carboxy-dipeptidase activity of the protease. Structure 2000; 8:305-13. [PMID: 10745011 DOI: 10.1016/s0969-2126(00)00108-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND Cathepsin X is a widespread, abundantly expressed papain-like mammalian lysosomal cysteine protease. It exhibits carboxy-monopeptidase as well as carboxy-dipeptidase activity and shares a similar activity profile with cathepsin B. The latter has been implicated in normal physiological events as well as in various pathological states such as rheumatoid arthritis, Alzheimer's disease and cancer progression. Thus the question is raised as to which of the two enzyme activities has actually been monitored. RESULTS The crystal structure of human cathepsin X has been determined at 2.67 A resolution. The structure shares the common features of a papain-like enzyme fold, but with a unique active site. The most pronounced feature of the cathepsin X structure is the mini-loop that includes a short three-residue insertion protruding into the active site of the protease. The residue Tyr27 on one side of the loop forms the surface of the S1 substrate-binding site, and His23 on the other side modulates both carboxy-monopeptidase as well as carboxy-dipeptidase activity of the enzyme by binding the C-terminal carboxyl group of a substrate in two different sidechain conformations. CONCLUSIONS The structure of cathepsin X exhibits a binding surface that will assist in the design of specific inhibitors of cathepsin X as well as of cathepsin B and thereby help to clarify the physiological roles of both proteases.
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Affiliation(s)
- G Guncar
- Department of Biochemistry and Molecular Biology, Jozef Stefan Institute, Ljubljana, 1000, Slovenia
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Turk B, Turk D, Turk V. Lysosomal cysteine proteases: more than scavengers. BIOCHIMICA ET BIOPHYSICA ACTA 2000; 1477:98-111. [PMID: 10708852 DOI: 10.1016/s0167-4838(99)00263-0] [Citation(s) in RCA: 568] [Impact Index Per Article: 23.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Lysosomal cysteine proteases were believed to be mainly involved in intracellular protein degradation. Under special conditions they have been found outside lysosomes resulting in pathological conditions. With the discovery of a series of new cathepsins with restricted tissue distributions, it has become evident that these enzymes must be involved in a range of specific cellular tasks much broader than as simple housekeeping enzymes. It is therefore timely to review and discuss the various physiological roles of mammalian lysosomal papain-like cysteine proteases as well as their mechanisms of action and the regulation of their activity.
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Affiliation(s)
- B Turk
- Department of Biochemistry and Molecular Biology, J. Stefan Institute, Jamova 39, 1000, Ljubljana, Slovenia.
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Tsuge H, Nishimura T, Tada Y, Asao T, Turk D, Turk V, Katunuma N. Inhibition mechanism of cathepsin L-specific inhibitors based on the crystal structure of papain-CLIK148 complex. Biochem Biophys Res Commun 1999; 266:411-6. [PMID: 10600517 DOI: 10.1006/bbrc.1999.1830] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Papain was used as an experimental model structure to understand the inhibition mechanism of newly developed specific inhibitors of cathepsin L, the papain superfamily. Recently, we developed a series of cathepsin L-specific inhibitors which are called the CLIK series [(1999) FEBS Lett. 458, 6-10]. Here, we report the complex structure of papain with CLIK148, which is a representative inhibitor from the CLIK series. The inhibitor complex structure was solved at 1.7 A resolution with conventional R 0.177. Unlike other epoxisuccinate inhibitors (E64, CA030, and CA074), CLIK148 uses both prime and nonprime sites, which are important for the specific inhibitory effect on cathepsin L. Also, the specificity for cathepsin L could be explained by the existence of Phe in the P2 site and hydrophobic interaction of N-terminal pyridine ring.
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Affiliation(s)
- H Tsuge
- Institute for Health Sciences, Tokushima Bunri University, Yamashiro-cho, Tokushima, 770-8514, Japan.
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Blagosklonny MV, An WG, Melillo G, Nguyen P, Trepel JB, Neckers LM. Regulation of BRCA1 by protein degradation. Oncogene 1999; 18:6460-8. [PMID: 10597248 DOI: 10.1038/sj.onc.1203068] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/1999] [Revised: 06/29/1999] [Accepted: 06/30/1999] [Indexed: 11/08/2022]
Abstract
BRCA1, a tumor suppressor protein implicated in hereditary forms of breast and ovarian cancer, is transcriptionally regulated in a proliferation-dependent manner. In this study, we demonstrate a substantial role for proteolysis in regulating the BRCA1 steady-state protein level in several cell lines. N-acetyl-leu-leu-norleucinal (ALLN), an inhibitor of the proteasome, calpain, and cathepsins, caused BRCA1 protein to accumulate in the nucleus of several human breast, prostate, and melanoma cell lines which express low or undetectable basal levels of BRCA1 protein, but not in cells with high basal expression of BRCA1. Protease inhibition did not increase BRCA1 synthesis, nor change its mRNA level, but it dramatically prolonged the protein's half-life. In contrast to ALLN, lactacystin and PS341, two specific proteasome inhibitors, as well as calpastatin peptide and PD150606, two selective calpain inhibitors, had no effect on BRCA1 stability, whereas ALLM, an effective calpain and cathepsin inhibitor but weak proteasome inhibitor, did stimulate accumulation of BRCA1. Moreover, three inhibitors of acidic cysteine proteases, chloroquine, ammonium chloride and bafilomycin, were as effective as ALLN. These results demonstrate that degradation by a cathepsin-like protease in fine balance with BRCA1 transcription is responsible for maintaining the low steady-state level of BRCA1 protein seen in many cancer cells.
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Affiliation(s)
- M V Blagosklonny
- Department of Therapeutics, National Cancer Institute, NIH, Bethesda, Maryland, MD 20892, USA
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