1
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Huang H, Tsui YM, Ho DWH, Chung CYS, Sze KMF, Lee E, Cheung GCH, Zhang VX, Wang X, Lyu X, Ng IOL. LANCL1, a cell surface protein, promotes liver tumor initiation through FAM49B-Rac1 axis to suppress oxidative stress. Hepatology 2024; 79:323-340. [PMID: 37540188 PMCID: PMC10789379 DOI: 10.1097/hep.0000000000000523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 05/25/2023] [Indexed: 08/05/2023]
Abstract
BACKGROUND AND AIMS HCC is an aggressive cancer with a poor clinical outcome. Understanding the mechanisms that drive tumor initiation is important for improving treatment strategy. This study aimed to identify functional cell membrane proteins that promote HCC tumor initiation. APPROACH AND RESULTS Tailor-made siRNA library screening was performed for all membrane protein-encoding genes that are upregulated in human HCC (n = 134), with sphere formation as a surrogate readout for tumor initiation. Upon confirmation of membranous localization by immunofluorescence and tumor initiation ability by limiting dilution assay in vivo, LanC-like protein-1 (LANCL1) was selected for further characterization. LANCL1 suppressed intracellular reactive oxygen species (ROS) and promoted tumorigenicity both in vitro and in vivo. Mechanistically, with mass spectrometry, FAM49B was identified as a downstream binding partner of LANCL1. LANCL1 stabilized FAM49B by blocking the interaction of FAM49B with the specific E3 ubiquitin ligase TRIM21, thus protecting FAM49B from ubiquitin-proteasome degradation. The LANCL1-FAM49B axis suppressed the Rac1-NADPH oxidase-driven ROS production, but this suppression of ROS was independent of the glutathione transferase function of LANCL1. Clinically, HCCs with high co-expression of LANCL1 and FAM49B were associated with more advanced tumor stage, poorer overall survival, and disease-free survival. In addition, anti-LANCL1 antibodies targeting the extracellular N-terminal domain were able to suppress the self-renewal ability, as demonstrated by the sphere formation ability of HCC cells. CONCLUSIONS Our data showed that LANCL1 is a cell surface protein and a key contributor to HCC initiation. Targeting the LANCL1-FAM49B-Rac1-NADPH oxidase-ROS signaling axis may be a promising therapeutic strategy for HCC.
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Affiliation(s)
- Hongyang Huang
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Yu-Man Tsui
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Daniel Wai-Hung Ho
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Clive Yik-Sham Chung
- Department of Pathology, The University of Hong Kong, Hong Kong
- School of Biomedical Sciences, The University of Hong Kong, Hong Kong
| | - Karen Man-Fong Sze
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Eva Lee
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Gary Cheuk-Hang Cheung
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Vanilla Xin Zhang
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Xia Wang
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Xueying Lyu
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Irene Oi-Lin Ng
- Department of Pathology, The University of Hong Kong, Hong Kong
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
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2
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Chan KKS, Au KY, Suen LH, Leung B, Wong CY, Leow WQ, Lim TKH, Ng IOL, Chung CYS, Lo RCL. Sortilin-Driven Cancer Secretome Enhances Tumorigenic Properties of Hepatocellular Carcinoma via de Novo Lipogenesis. Am J Pathol 2023; 193:2156-2171. [PMID: 37673328 DOI: 10.1016/j.ajpath.2023.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 07/18/2023] [Accepted: 08/02/2023] [Indexed: 09/08/2023]
Abstract
A growing body of evidence suggests de novo lipogenesis as a key metabolic pathway adopted by cancers to fuel tumorigenic processes. While increased de novo lipogenesis has also been reported in hepatocellular carcinoma (HCC), understanding on molecular mechanisms driving de novo lipogenesis remains limited. In the present study, the functional role of sortilin, a member of the vacuolar protein sorting 10 protein receptor family, in HCC was investigated. Sortilin was overexpressed in HCC and was associated with poorer survival outcome. In functional studies, sortilin-overexpressing cells conferred tumorigenic phenotypes, namely, self-renewal and metastatic potential, of HCC cells via the cancer secretome. Proteomic profiling highlighted fatty acid metabolism as a potential molecular pathway associated with sortilin-driven cancer secretome. This finding was validated by the increased lipid content and expression of fatty acid synthase (FASN) in HCC cells treated with conditioned medium collected from sortilin-overexpressing cells. The enhanced tumorigenic properties endowed by sortilin-driven cancer secretome were partly abrogated by co-administration of FASN inhibitor C75. Further mechanistic dissection suggested protein stabilization by post-translational modification with O-GlcNAcylation as a major mechanism leading to augmented FASN expression. In conclusion, the present study uncovered the role of sortilin in hepatocarcinogenesis via modulation of the cancer secretome and deregulated lipid metabolism.
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Affiliation(s)
- Kristy Kwan-Shuen Chan
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Kwan-Yung Au
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Long-Hin Suen
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Bernice Leung
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Cheuk-Yan Wong
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Wei-Qiang Leow
- Department of Anatomical Pathology, Singapore General Hospital & Duke-NUS Medical School, Singapore
| | - Tony Kiat-Hon Lim
- Department of Anatomical Pathology, Singapore General Hospital & Duke-NUS Medical School, Singapore
| | - Irene Oi-Lin Ng
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong, China
| | - Clive Yik-Sham Chung
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; School of Biomedical Sciences, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China
| | - Regina Cheuk-Lam Lo
- Department of Pathology, School of Clinical Medicine, LKS Faculty of Medicine, The University of Hong Kong, Hong Kong, China; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong, China.
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Koo TY, Lai H, Nomura DK, Chung CYS. N-Acryloylindole-alkyne (NAIA) enables imaging and profiling new ligandable cysteines and oxidized thiols by chemoproteomics. Nat Commun 2023; 14:3564. [PMID: 37322008 PMCID: PMC10272157 DOI: 10.1038/s41467-023-39268-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2022] [Accepted: 06/02/2023] [Indexed: 06/17/2023] Open
Abstract
Cysteine has been exploited as the binding site of covalent drugs. Its high sensitivity to oxidation is also important for regulating cellular processes. To identify new ligandable cysteines which can be hotspots for therapy and to better study cysteine oxidations, we develop cysteine-reactive probes, N-acryloylindole-alkynes (NAIAs), which have superior cysteine reactivity owing to delocalization of π electrons of the acrylamide warhead over the whole indole scaffold. This allows NAIAs to probe functional cysteines more effectively than conventional iodoacetamide-alkyne, and to image oxidized thiols by confocal fluorescence microscopy. In mass spectrometry experiments, NAIAs successfully capture new oxidized cysteines, as well as a new pool of ligandable cysteines and proteins. Competitive activity-based protein profiling experiments further demonstrate the ability of NAIA to discover lead compounds targeting these cysteines and proteins. We show the development of NAIAs with activated acrylamide for advancing proteome-wide profiling and imaging ligandable cysteines and oxidized thiols.
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Affiliation(s)
- Tin-Yan Koo
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China
| | - Hinyuk Lai
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China
| | - Daniel K Nomura
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - Clive Yik-Sham Chung
- School of Biomedical Sciences, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China.
- Department of Pathology, School of Clinical Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong, P. R. China.
- Centre for Oncology and Immunology, Hong Kong Science Park, Hong Kong, P. R. China.
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4
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Husain A, Chiu YT, Sze KMF, Ho DWH, Tsui YM, Suarez EMS, Zhang VX, Chan LK, Lee E, Lee JMF, Cheung TT, Wong CCL, Chung CYS, Ng IOL. Ephrin-A3/EphA2 axis regulates cellular metabolic plasticity to enhance cancer stemness in hypoxic hepatocellular carcinoma. J Hepatol 2022; 77:383-396. [PMID: 35227773 DOI: 10.1016/j.jhep.2022.02.018] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Revised: 01/19/2022] [Accepted: 02/13/2022] [Indexed: 02/08/2023]
Abstract
BACKGROUND & AIMS The highly proliferative nature of hepatocellular carcinoma (HCC) frequently results in a hypoxic intratumoural microenvironment, which creates a therapeutic challenge owing to a lack of mechanistic understanding of the phenomenon. We aimed to identify critical drivers of HCC development and progression in the hypoxic microenvironment. METHODS We performed integrative analysis of multiple transcriptomic and genomic profiles specific for HCC and hypoxia and identified the Ephrin-A3/Eph receptor A2 (EphA2) axis as a clinically relevant and hypoxia-inducible signalling axis in HCC. The functional significance and mechanistic consequences of the Ephrin-A3/EphA2 axis were examined in EFNA3- and EPHA2- knockdown/overexpressing HCC cells. The potential downstream pathways were investigated by transcriptome sequencing, quantitative reverse-transcription PCR, western blotting analysis and metabolomics. RESULTS EFNA3 was frequently upregulated in HCC and its overexpression was associated with more aggressive tumour behaviours. HIF-1α directly and positively regulated EFNA3 expression under hypoxia. EFNA3 functionally contributed to self-renewal, proliferation and migration in HCC cells. EphA2 was identified as a key functional downstream mediator of EFNA3. Functional characterisation of the Ephrin-A3/EphA2 forward-signalling axis demonstrated a promotion of self-renewal ability and tumour initiation. Mechanistically, the Ephrin-A3/EphA2 axis promoted the maturation of SREBP1 and expression of its transcriptional target, ACLY, was significantly associated with the expression of EFNA3 and hypoxia markers in clinical cohorts. The metabolic signature of EPHA2 and ACLY stable knockdown HCC cells demonstrated significant overlap in fatty acid, cholesterol and tricarboxylic acid cycle metabolite profiles. ACLY was confirmed to mediate the self-renewal function of the Ephrin-A3/EphA2 axis. CONCLUSIONS Our findings revealed the novel role of the Ephrin-A3/EphA2 axis as a hypoxia-sensitive modulator of HCC cell metabolism and a key contributor to HCC initiation and progression. LAY SUMMARY Hepatocellular carcinoma (HCC) is a fast-growing tumour; hence, areas of the tumour often have insufficient vasculature and become hypoxic. The presence of hypoxia within tumours has been shown to negatively impact on the survival of patients with tumours, including HCC. Herein, we identified the Ephrin-A3/EphA2 axis as a key functional driver of tumour initiation and progression in response to hypoxia. Additionally, we showed that SREBP1-ACLY-mediated metabolic rewiring was an important downstream effector that induced cancer stemness in response to Ephrin-A3/EphA2 forward-signalling.
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Affiliation(s)
- Abdullah Husain
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Yung-Tuen Chiu
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Karen Man-Fong Sze
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Daniel Wai-Hung Ho
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Yu-Man Tsui
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Eliana Mary Senires Suarez
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Vanilla Xin Zhang
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Lo-Kong Chan
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Eva Lee
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Joyce Man-Fong Lee
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Tan-To Cheung
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong; Department of Surgery, The University of Hong Kong, Hong Kong
| | - Carmen Chak-Lui Wong
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Clive Yik-Sham Chung
- Department of Pathology, The University of Hong Kong, Hong Kong; School of Biomedical Science, The University of Hong Kong, Hong Kong
| | - Irene Oi-Lin Ng
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong.
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5
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Bao MHR, Yang C, Tse APW, Wei L, Lee D, Zhang MS, Goh CC, Chiu DKC, Yuen VWH, Law CT, Chin WC, Chui NNQ, Wong BPY, Chan CYK, Ng IOL, Chung CYS, Wong CM, Wong CCL. Genome-wide CRISPR-Cas9 knockout library screening identified PTPMT1 in cardiolipin synthesis is crucial to survival in hypoxia in liver cancer. Cell Rep 2021; 34:108676. [PMID: 33503428 DOI: 10.1016/j.celrep.2020.108676] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Revised: 11/11/2020] [Accepted: 12/30/2020] [Indexed: 12/17/2022] Open
Abstract
Hypoxia, low oxygen (O2), is a key feature of all solid cancers, including hepatocellular carcinoma (HCC). Genome-wide CRISPR-Cas9 knockout library screening is used to identify reliable therapeutic targets responsible for hypoxic survival in HCC. We find that protein-tyrosine phosphatase mitochondrial 1 (PTPMT1), an important enzyme for cardiolipin (CL) synthesis, is the most significant gene and ranks just after hypoxia-inducible factor (HIF)-1α and HIF-1β as crucial to hypoxic survival. CL constitutes the mitochondrial membrane and ensures the proper assembly of electron transport chain (ETC) complexes for efficient electron transfer in respiration. ETC becomes highly unstable during hypoxia. Knockout of PTPMT1 stops the maturation of CL and impairs the assembly of ETC complexes, leading to further electron leakage and ROS accumulation at ETC in hypoxia. Excitingly, HCC cells, especially under hypoxic conditions, show great sensitivity toward PTPMT1 inhibitor alexidine dihydrochloride (AD). This study unravels the protective roles of PTPMT1 in hypoxic survival and cancer development.
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Affiliation(s)
| | - Chunxue Yang
- Department of Pathology, The University of Hong Kong, Hong Kong
| | - Aki Pui-Wah Tse
- Department of Pathology, The University of Hong Kong, Hong Kong
| | - Lai Wei
- Department of Pathology, The University of Hong Kong, Hong Kong
| | - Derek Lee
- Department of Pathology, The University of Hong Kong, Hong Kong
| | | | - Chi Ching Goh
- Department of Pathology, The University of Hong Kong, Hong Kong
| | | | | | - Cheuk-Ting Law
- Department of Pathology, The University of Hong Kong, Hong Kong
| | - Wai-Ching Chin
- Department of Pathology, The University of Hong Kong, Hong Kong
| | | | | | | | - Irene Oi-Lin Ng
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Clive Yik-Sham Chung
- Department of Pathology, The University of Hong Kong, Hong Kong; School of Biomedical Sciences, The University of Hong Kong, Hong Kong
| | - Chun-Ming Wong
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong.
| | - Carmen Chak-Lui Wong
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong.
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6
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Lee S, Chung CYS, Liu P, Craciun L, Nishikawa Y, Bruemmer KJ, Hamachi I, Saijo K, Miller EW, Chang CJ. Activity-Based Sensing with a Metal-Directed Acyl Imidazole Strategy Reveals Cell Type-Dependent Pools of Labile Brain Copper. J Am Chem Soc 2020; 142:14993-15003. [PMID: 32815370 PMCID: PMC7877313 DOI: 10.1021/jacs.0c05727] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [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: 12/14/2022]
Abstract
Copper is a required nutrient for life and particularly important to the brain and central nervous system. Indeed, copper redox activity is essential to maintaining normal physiological responses spanning neural signaling to metabolism, but at the same time copper misregulation is associated with inflammation and neurodegeneration. As such, chemical probes that can track dynamic changes in copper with spatial resolution, especially in loosely bound, labile forms, are valuable tools to identify and characterize its contributions to healthy and disease states. In this report, we present an activity-based sensing (ABS) strategy for copper detection in live cells that preserves spatial information by a copper-dependent bioconjugation reaction. Specifically, we designed copper-directed acyl imidazole dyes that operate through copper-mediated activation of acyl imidazole electrophiles for subsequent labeling of proximal proteins at sites of elevated labile copper to provide a permanent stain that resists washing and fixation. To showcase the utility of this new ABS platform, we sought to characterize labile copper pools in the three main cell types in the brain: neurons, astrocytes, and microglia. Exposure of each of these cell types to physiologically relevant stimuli shows distinct changes in labile copper pools. Neurons display translocation of labile copper from somatic cell bodies to peripheral processes upon activation, whereas astrocytes and microglia exhibit global decreases and increases in intracellular labile copper pools, respectively, after exposure to inflammatory stimuli. This work provides foundational information on cell type-dependent homeostasis of copper, an essential metal in the brain, as well as a starting point for the design of new activity-based probes for metals and other dynamic signaling and stress analytes in biology.
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Affiliation(s)
| | | | | | | | - Yuki Nishikawa
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
- ERATO Innovative Molecular Technology for Neuroscience Project, Japan Science and Technology Agency (JST), Kyoto 615-8530, Japan
| | | | - Itaru Hamachi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
- ERATO Innovative Molecular Technology for Neuroscience Project, Japan Science and Technology Agency (JST), Kyoto 615-8530, Japan
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7
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Tang FK, Yu ZH, Wong THF, Chung CYS, Hirao H, Au-Yeung HY. Fluorescein-Containing Superoxide Probes with a Modular Copper-Based Trigger. Chempluschem 2020; 85:653-658. [PMID: 32237224 DOI: 10.1002/cplu.202000059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 03/13/2020] [Indexed: 12/22/2022]
Abstract
Fluorescein-derived superoxide probes featuring a copper(II) complex that can be activated by superoxide to initiate ether bond cleavage and uncage a fluorescein reporter for imaging in live cells are described. Compared to other superoxide sensing moieties, this bond cleavage strategy can be modularly adapted to fluorescent reporters with different properties without compromising the superoxide reactivity and selectivity. A green-emitting probe and its lysosome-targeting analogue have been successfully developed. Both probes are sensitive with more than 30-fold fluorescence enhancement towards superoxide and are highly selective with no significant response towards other reactive oxygen species. A structure-activity relationship study of the copper-based superoxide trigger showed that the secondary coordination environment of the copper(II) center is important for the superoxide reactivity and selectivity. The probes have been applied in imaging changes in intracellular superoxide level in live HeLa and HEK293T cells upon menadione stimulation and also in a cellular inflammation model in RAW 264.7 cells.
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Affiliation(s)
- Fung Kit Tang
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Zuo Hang Yu
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Thomas Hin-Fung Wong
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Clive Yik-Sham Chung
- Department of Chemistry, University of California, Berkeley, California, CA, 94720, USA
| | - Hajime Hirao
- Department of Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, P. R. China
| | - Ho Yu Au-Yeung
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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Chung CYS, Shin HR, Berdan CA, Ford B, Ward CC, Olzmann JA, Zoncu R, Nomura DK. Covalent targeting of the vacuolar H +-ATPase activates autophagy via mTORC1 inhibition. Nat Chem Biol 2019; 15:776-785. [PMID: 31285595 PMCID: PMC6641988 DOI: 10.1038/s41589-019-0308-4] [Citation(s) in RCA: 96] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2019] [Accepted: 05/15/2019] [Indexed: 02/06/2023]
Abstract
Autophagy is a lysosomal degradation pathway that eliminates aggregated proteins and damaged organelles to maintain cellular homeostasis. A major route for activating autophagy involves inhibition of the mTORC1 kinase, but current mTORC1-targeting compounds do not allow complete and selective mTORC1 blockade. Here, we have coupled screening of a covalent ligand library with activity-based protein profiling to discover EN6, a small-molecule in vivo activator of autophagy that covalently targets cysteine 277 in the ATP6V1A subunit of the lysosomal v-ATPase, which activates mTORC1 via the Rag guanosine triphosphatases. EN6-mediated ATP6V1A modification decouples the v-ATPase from the Rags, leading to inhibition of mTORC1 signaling, increased lysosomal acidification and activation of autophagy. Consistently, EN6 clears TDP-43 aggregates, a causative agent in frontotemporal dementia, in a lysosome-dependent manner. Our results provide insight into how the v-ATPase regulates mTORC1, and reveal a unique approach for enhancing cellular clearance based on covalent inhibition of lysosomal mTORC1 signaling.
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Affiliation(s)
- Clive Yik-Sham Chung
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA
- Novartis-Berkeley Center for Proteomics and Chemistry Technologies, Berkeley, CA, USA
| | - Hijai R Shin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
- The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA
| | - Charles A Berdan
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, USA
| | - Breanna Ford
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, USA
| | - Carl C Ward
- Novartis-Berkeley Center for Proteomics and Chemistry Technologies, Berkeley, CA, USA
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA
| | - James A Olzmann
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, USA
| | - Roberto Zoncu
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- The Paul F. Glenn Center for Aging Research at the University of California, Berkeley, Berkeley, CA, USA.
| | - Daniel K Nomura
- Department of Chemistry, University of California, Berkeley, Berkeley, CA, USA.
- Novartis-Berkeley Center for Proteomics and Chemistry Technologies, Berkeley, CA, USA.
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA, USA.
- Department of Nutritional Sciences and Toxicology, University of California, Berkeley, CA, USA.
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9
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Chung CYS, Timblin GA, Saijo K, Chang CJ. Versatile Histochemical Approach to Detection of Hydrogen Peroxide in Cells and Tissues Based on Puromycin Staining. J Am Chem Soc 2018; 140:6109-6121. [PMID: 29722974 PMCID: PMC6069982 DOI: 10.1021/jacs.8b02279] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [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: 12/12/2022]
Abstract
Hydrogen peroxide (H2O2) is a central reactive oxygen species (ROS) that contributes to diseases from obesity to cancer to neurodegeneration but is also emerging as an important signaling molecule. We now report a versatile histochemical approach for detection of H2O2 that can be employed across a broad range of cell and tissue specimens in both healthy and disease states. We have developed a first-generation H2O2-responsive analogue named Peroxymycin-1, which is based on the classic cell-staining molecule puromycin and enables covalent staining of biological samples and retains its signal after fixation. H2O2-mediated boronate cleavage uncages the puromycin aminonucleoside, which leaves a permanent and dose-dependent mark on treated biological specimens that can be detected with high sensitivity and precision through a standard immunofluorescence assay. Peroxymycin-1 is selective and sensitive enough to image both exogenous and endogenous changes in cellular H2O2 levels and can be exploited to profile resting H2O2 levels across a panel of cell lines to distinguish metastatic, invasive cancer cells from less invasive cancer and nontumorigenic counterparts, based on correlations with ROS status. Moreover, we establish that Peroxymycin-1 is an effective histochemical probe for in vivo H2O2 analysis, as shown through identification of aberrant elevations in H2O2 levels in liver tissues in a murine model of nonalcoholic fatty liver disease, thus demonstrating the potential of this approach for studying disease states and progression associated with H2O2. This work provides design principles that should enable development of a broader range of histochemical probes for biological use that operate via activity-based sensing.
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Affiliation(s)
- Clive Yik-Sham Chung
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
| | - Greg A. Timblin
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
| | - Kaoru Saijo
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
| | - Christopher J. Chang
- Department of Chemistry, University of California, Berkeley, Berkeley, California 94720, United States
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
- Howard Hughes Medical Institute, University of California, Berkeley, Berkeley, California 94720, United States
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10
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Abstract
We report here a new bioinspired copper-based strategy of superoxide sensing and the development of sensitive (>90-fold fluorescence turn-on) and selective superoxide probes for imaging variations in the endogenous superoxide level in various live mammalian cells (HEK293T, HeLa and A431).
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Affiliation(s)
- Zuo Hang Yu
- Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China.
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11
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Siu SKL, Chung CYS, Yam VWW. Amphiphilic oligo(ethylene glycol)- and poly(ethyleneoxide)-block-poly(propylene oxide)-block-poly-(ethylene oxide)-containing cyclometalated alkynylgold(III) complexes: From basic photophysics to self-assembly and stimuli-responsive properties. J Organomet Chem 2017. [DOI: 10.1016/j.jorganchem.2017.04.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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12
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Cheng HK, Chung CYS, Zhang K, Yam VWW. Inside Back Cover: Simple and Versatile Preparation of Luminescent Amphiphilic Platinum(II)-containing Polystyrene Complexes With Transformable Nanostructures Assisted by Pt⋅⋅⋅Pt and π-π Interactions (Chem. Asian J. 13/2017). Chem Asian J 2017. [DOI: 10.1002/asia.201700468] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Heung-Kiu Cheng
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
| | - Clive Yik-Sham Chung
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
| | - Kaka Zhang
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
| | - Vivian Wing-Wah Yam
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
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13
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Cheng HK, Chung CYS, Zhang K, Yam VWW. Simple and Versatile Preparation of Luminescent Amphiphilic Platinum(II)-containing Polystyrene Complexes With Transformable Nanostructures Assisted by Pt⋅⋅⋅Pt and π-π Interactions. Chem Asian J 2017; 12:1509-1516. [DOI: 10.1002/asia.201700123] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Revised: 02/28/2017] [Indexed: 11/07/2022]
Affiliation(s)
- Heung-Kiu Cheng
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
| | - Clive Yik-Sham Chung
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
| | - Kaka Zhang
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
| | - Vivian Wing-Wah Yam
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong
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14
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Chung CYS, Fung SK, Tong KC, Wan PK, Lok CN, Huang Y, Chen T, Che CM. A multi-functional PEGylated gold(iii) compound: potent anti-cancer properties and self-assembly into nanostructures for drug co-delivery. Chem Sci 2017; 8:1942-1953. [PMID: 28451309 PMCID: PMC5384453 DOI: 10.1039/c6sc03210a] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Accepted: 11/08/2016] [Indexed: 11/26/2022] Open
Abstract
Gold(iii) porphyrin-PEG conjugates [Au(TPP-COO-PEG5000-OCH3)]Cl (1) and [Au(TPP-CONH-PEG5000-OCH3)]Cl (2) have been synthesized and characterized. Based on the amphiphilic character of the conjugates, they were found to undergo self-assembly into nanostructures with size 120-200 nm and this did not require the presence of other surfactants or components for nano-assembly, unlike most conventional drug nano-formulations. With a readily hydrolyzable ester linkage, chemotherapeutic [Au(TPP-COOH)]+ exhibited triggered release from the conjugate 1 in acidic buffer solution as well as in vitro and in vivo without the formation of toxic side products. The nanostructures of 1 showed higher cellular uptake into cancer cells compared to non-tumorigenic cells, owing to their energy-dependent uptake mechanism. This, together with a generally higher metabolic rate and more acidic nature of cancer cells which can lead to faster hydrolysis of the ester bond, afforded 1 with excellent selectivity in killing cancer cells compared with non-tumorigenic cells in vitro. This was corroborated by fluorescence microscopy imaging and flow cytometric analysis of co-culture model of colon cancer (HCT116) and normal colon (NCM460) cells. In vivo experiments showed that treatment of nude mice bearing HCT116 xenografts with 1 resulted in significant inhibition of tumor growth and, more importantly, minimal systemic toxicity as revealed by histopathological analysis of tissue sections and blood biochemisty. The latter is explained by a lower accumulation of 1 in organs of treated mice at its effective dosage, as compared to that of other gold(iii) porphyrin complexes. Co-assembly of 1 and doxorubicin resulted in encapsulation of doxorubicin by the nanostructures of 1. The nanocomposites demonstrated a strong synergism on killing cancer cells and could overcome efflux pump-mediated drug-resistance in a doxorubicin-resistant ovarian cancer cell line (A2780adr) which was found in cells incubated with doxorubicin alone. Also, the nanocomposites accumulated more slowly in non-tumorigenic cells, resulting in a lower toxicity toward non-tumorigenic cells. These results indicate the potential application of 1 not only as an anti-cancer agent but also as a nanoscale drug carrier for chemotherapy.
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Affiliation(s)
- Clive Yik-Sham Chung
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry and Chemical Biology Centre , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Sin-Ki Fung
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry and Chemical Biology Centre , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Ka-Chung Tong
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry and Chemical Biology Centre , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Pui-Ki Wan
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry and Chemical Biology Centre , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chun-Nam Lok
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry and Chemical Biology Centre , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Yanyu Huang
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Tianfeng Chen
- Department of Chemistry , Jinan University , Guangzhou 510632 , China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry , Department of Chemistry and Chemical Biology Centre , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
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15
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Fong TTH, Lok CN, Chung CYS, Fung YME, Chow PK, Wan PK, Che CM. Cyclometalated Palladium(II) N-Heterocyclic Carbene Complexes: Anticancer Agents for Potent In Vitro Cytotoxicity and In Vivo Tumor Growth Suppression. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201602814] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Tommy Tsz-Him Fong
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Chun-Nam Lok
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Clive Yik-Sham Chung
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Yi-Man Eva Fung
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Pui-Keong Chow
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Pui-Ki Wan
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry; Institute of Molecular Functional Materials and Department of Chemistry; The University of Hong Kong; Pokfulam Road Hong Kong China
- HKU Shenzhen Institute of Research and Innovation; Shenzhen 518053 China
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16
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Fong TTH, Lok CN, Chung CYS, Fung YME, Chow PK, Wan PK, Che CM. Cyclometalated Palladium(II) N-Heterocyclic Carbene Complexes: Anticancer Agents for Potent In Vitro Cytotoxicity and In Vivo Tumor Growth Suppression. Angew Chem Int Ed Engl 2016; 55:11935-9. [PMID: 27571430 DOI: 10.1002/anie.201602814] [Citation(s) in RCA: 76] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Revised: 06/15/2016] [Indexed: 01/23/2023]
Abstract
Palladium(II) complexes are generally reactive toward substitution/reduction, and their biological applications are seldom explored. A new series of palladium(II) N-heterocyclic carbene (NHC) complexes that are stable in the presence of biological thiols are reported. A representative complex, [Pd(C^N^N)(N,N'-nBu2 NHC)](CF3 SO3 ) (Pd1 d, HC^N^N=6-phenyl-2,2'-bipyridine, N,N'-nBu2 NHC=N,N'-di-n-butylimidazolylidene), displays potent killing activity toward cancer cell lines (IC50 =0.09-0.5 μm) but is less cytotoxic toward a normal human fibroblast cell line (CCD-19Lu, IC50 =11.8 μm). In vivo anticancer studies revealed that Pd1 d significantly inhibited tumor growth in a nude mice model. Proteomics data and in vitro biochemical assays reveal that Pd1 d exerts anticancer effects, including inhibition of an epidermal growth factor receptor pathway, induction of mitochondrial dysfunction, and antiangiogenic activity to endothelial cells.
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Affiliation(s)
- Tommy Tsz-Him Fong
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Chun-Nam Lok
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Clive Yik-Sham Chung
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Yi-Man Eva Fung
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Pui-Keong Chow
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Pui-Ki Wan
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry, Institute of Molecular Functional Materials and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, China. .,HKU Shenzhen Institute of Research and Innovation, Shenzhen, 518053, China.
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17
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Chow PK, Cheng G, Tong GSM, Ma C, Kwok WM, Ang WH, Chung CYS, Yang C, Wang F, Che CM. Highly luminescent palladium(ii) complexes with sub-millisecond blue to green phosphorescent excited states. Photocatalysis and highly efficient PSF-OLEDs. Chem Sci 2016; 7:6083-6098. [PMID: 30034749 PMCID: PMC6024183 DOI: 10.1039/c6sc00462h] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 05/23/2016] [Indexed: 01/01/2023] Open
Abstract
Palladium(ii) complexes supported by tetradentate [N^C^C^N] and [O^N^C^N] ligand systems display sky blue to red phosphorescence with emission quantum yields and emission lifetimes up to 0.64 and 272 μs, respectively. Femtosecond time-resolved fluorescence (fs-TRF) measurements on these Pd(ii) complexes reveal a fast intersystem crossing from singlet to triplet manifolds with time constants of 0.6-21 ps. DFT/TDDFT calculations revealed that, as a result of the spiro-fluorene and bridging tertiary amine units of the ligands, the T1 excited state is more ligand-localized and has smaller structural distortion, leading to slower non-radiative decay as well as radiative decay of T1 → S0 transition and thereby highly emissive, long-lived triplet excited states. The Pd(ii) complexes have been found to be efficient catalysts for visible light-driven, reductive C-C bond formation from unactivated alkyl bromides with conversions and yields of up to 90% and 83%, respectively. These complexes have also been employed as photosensitizers for [2 + 2] cycloaddition of styrenes, with conversions and yields comparable to those of the reported Ir(iii) complexes. Both green and sky blue organic-light emitting devices (OLEDs) have been generated with these Pd(ii) complexes as guest emitters. Maximum external quantum efficiencies (EQE) of up to 16.5% have been achieved in the sky blue OLEDs. The long emission lifetimes render the Pd(ii) complexes good sensitizers for phosphor-sensitized fluorescent OLEDs (PSF-OLEDs). By utilizing these phosphorescent Pd(ii) complexes as sensitizers, highly efficient green and yellow PSF-OLEDs having high EQE (up to 14.3%), high colour purity and long operation lifetimes, with 90% of initial luminance (LT90) for more than 80 000 h, have been realized.
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Affiliation(s)
- Pui-Keong Chow
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Gang Cheng
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen 518053 , China
| | - Glenna So Ming Tong
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chensheng Ma
- School of Chemistry and Chemical Engineering , Shenzhen University , Shenzhen 518060 , China
| | - Wai-Ming Kwok
- Department of Applied Biology and Chemical Technology , The Hong Kong Polytechnic University , Hung Hom , Kowloon , Hong Kong SAR , China
| | - Wai-Hung Ang
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Clive Yik-Sham Chung
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chen Yang
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Feng Wang
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen 518053 , China
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Chung CYS, Li SPY, Lo KKW, Yam VWW. Synthesis and Electrochemical, Photophysical, and Self-Assembly Studies on Water-Soluble pH-Responsive Alkynylplatinum(II) Terpyridine Complexes. Inorg Chem 2016; 55:4650-63. [DOI: 10.1021/acs.inorgchem.6b00513] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Clive Yik-Sham Chung
- Institute of Molecular
Functional Materials [Areas of Excellence Scheme, University Grants
Committee (Hong Kong)] and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
| | - Steve Po-Yam Li
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon,
Hong Kong, P. R. China
| | - Kenneth Kam-Wing Lo
- Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon,
Hong Kong, P. R. China
| | - Vivian Wing-Wah Yam
- Institute of Molecular
Functional Materials [Areas of Excellence Scheme, University Grants
Committee (Hong Kong)] and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P. R. China
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Affiliation(s)
- Frankie Chi-Ming Leung
- Institute of Molecular Functional
Materials (Areas of Excellence Scheme, University Grants Committee
(Hong Kong)) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P. R. China
| | - Sammual Yu-Lut Leung
- Institute of Molecular Functional
Materials (Areas of Excellence Scheme, University Grants Committee
(Hong Kong)) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P. R. China
| | - Clive Yik-Sham Chung
- Institute of Molecular Functional
Materials (Areas of Excellence Scheme, University Grants Committee
(Hong Kong)) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P. R. China
| | - Vivian Wing-Wah Yam
- Institute of Molecular Functional
Materials (Areas of Excellence Scheme, University Grants Committee
(Hong Kong)) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong SAR, P. R. China
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20
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Chan K, Yik-Sham Chung C, Wing-Wah Yam V. Parallel folding topology-selective label-free detection and monitoring of conformational and topological changes of different G-quadruplex DNAs by emission spectral changes via FRET of mPPE-Ala-Pt(ii) complex ensemble. Chem Sci 2016; 7:2842-2855. [PMID: 30090278 PMCID: PMC6055111 DOI: 10.1039/c5sc04563k] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/05/2016] [Indexed: 12/28/2022] Open
Abstract
The formation of supramolecular assemblies between [Pt(bzimpy-Et){C[triple bond, length as m-dash]CC6H4(CH2NMe3-4)}]Cl2 (1) and mPPE-Ala and the FRET properties of the ensemble have been revealed from the UV-vis absorption, steady-state emission and time-resolved emission decay studies. The two-component mPPE-Ala-1 ensemble has been employed in a "proof-of-principle" concept for label-free detection of G-quadruplex DNAs with the intramolecular propeller parallel folding topology, such as c-myc, in aqueous buffer solution. By the modulation of the aggregation/deaggregation of the polymer-metal complex aggregates and hence the FRET from the mPPE-Ala donor to the aggregated 1 as acceptor, the ensemble has been demonstrated for sensitive and selective label-free detection of c-myc via the monitoring of emission spectral changes of the ensemble. Ratiometric emission of the ensemble at 461 and 662 nm has been shown to distinguish the intramolecular propeller parallel G-quadruplex folding topology of c-myc from other G-quadruplex-forming sequences of different folding topologies, owing to the strong and specific interactions between c-myc and 1 as suggested by the UV-vis absorption and UV melting studies. In addition, the formation of high-order intermolecular multimeric G-quadruplexes from c-myc under molecular crowding conditions has been successfully probed by the ratiometric emission of the ensemble. The conformational and topological transition of human telomeric DNA from the mixed-hybrid form to the intramolecular propeller parallel form, as observed from the circular dichroism spectroscopy, has also been monitored by the ratiometric emission of the ensemble. The ability of the ensemble to detect these conformational and topological transitions of G-quadruplex DNAs has been rationalized by the excellent selectivity and sensitivity of the ensemble towards the intramolecular propeller parallel G-quadruplex DNAs and their high-order intermolecular multimers, which are due to the extra stabilization gained from Pt···Pt and π-π interactions in addition to the electrostatic and hydrophobic interactions found in the polymer-metal complex aggregates.
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Affiliation(s)
- Kevin Chan
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , P. R. China .
| | - Clive Yik-Sham Chung
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , P. R. China .
| | - Vivian Wing-Wah Yam
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) , Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , P. R. China .
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21
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Yang C, Mehmood F, Lam TL, Chan SLF, Wu Y, Yeung CS, Guan X, Li K, Chung CYS, Zhou CY, Zou T, Che CM. Stable luminescent iridium(iii) complexes with bis(N-heterocyclic carbene) ligands: photo-stability, excited state properties, visible-light-driven radical cyclization and CO 2 reduction, and cellular imaging. Chem Sci 2016; 7:3123-3136. [PMID: 29997803 PMCID: PMC6003676 DOI: 10.1039/c5sc04458h] [Citation(s) in RCA: 95] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 01/20/2016] [Indexed: 11/24/2022] Open
Abstract
Excited state properties, photo-catalysis and cellular imaging of photo-stable bis-NHC Ir(iii) complexes are described.
A new class of cyclometalated Ir(iii) complexes supported by various bidentate C-deprotonated (C^N) and cis-chelating bis(N-heterocyclic carbene) (bis-NHC) ligands has been synthesized. These complexes display strong emission in deaerated solutions at room temperature with photoluminescence quantum yields up to 89% and emission lifetimes up to 96 μs. A photo-stable complex containing C-deprotonated fluorenyl-substituted C^N shows no significant decomposition even upon irradiation for over 120 h by blue LEDs (12 W). These, together with the strong absorption in the visible region and rich photo-redox properties, allow the bis-NHC Ir(iii) complexes to act as good photo-catalysts for reductive C–C bond formation from C(sp3/sp2)–Br bonds cleavage using visible-light irradiation (λ > 440 nm). A water-soluble complex with a glucose-functionalized bis-NHC ligand catalysed a visible-light-driven radical cyclization for the synthesis of pyrrolidine in aqueous media. Also, the bis-NHC Ir(iii) complex in combination with a cobalt catalyst can catalyse the visible-light-driven CO2 reduction with excellent turnover numbers (>2400) and selectivity (CO over H2 in gas phase: >95%). Additionally, this series of bis-NHC Ir(iii) complexes are found to localize in and stain endoplasmic reticulum (ER) of various cell lines with high selectivity, and exhibit high cytotoxicity towards cancer cells, revealing their potential uses as bioimaging and/or anti-cancer agents.
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Affiliation(s)
- Chen Yang
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen , China
| | - Faisal Mehmood
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Tsz Lung Lam
- The Hong Kong Polytechnic University Shenzhen Research Institute , Shenzhen , PR China.,Department of Applied Biology and Chemical Technology , The Hong Kong Polytechnic University , Hung Hom , Hong Kong , China .
| | - Sharon Lai-Fung Chan
- The Hong Kong Polytechnic University Shenzhen Research Institute , Shenzhen , PR China.,Department of Applied Biology and Chemical Technology , The Hong Kong Polytechnic University , Hung Hom , Hong Kong , China .
| | - Yuan Wu
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chi-Shun Yeung
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Xiangguo Guan
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Kai Li
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen , China
| | - Clive Yik-Sham Chung
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Cong-Ying Zhou
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen , China
| | - Taotao Zou
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China .
| | - Chi-Ming Che
- State Key Laboratory of Synthetic Chemistry , Institute of Molecular Functional Materials , HKU-CAS Joint Laboratory on New Materials and Department of Chemistry , The University of Hong Kong , Pokfulam Road , Hong Kong , China . .,HKU Shenzhen Institute of Research and Innovation , Shenzhen , China
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22
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Chung CYS, Tamaru SI, Shinkai S, Yam VWW. Supramolecular Assembly of Achiral Alkynylplatinum(II) Complexes and Carboxylic β-1,3-Glucan into Different Helical Handedness Stabilized by Pt⋅⋅⋅Pt and/or π-π Interactions. Chemistry 2015; 21:5447-58. [DOI: 10.1002/chem.201405035] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Indexed: 12/19/2022]
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23
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Chung CYS, Yam VWW. Dual pH- and Temperature-Responsive Metallosupramolecular Block Copolymers with Tunable Critical Micelle Temperature by Modulation of the Self-Assembly of NIR-Emissive Alkynylplatinum(II) Complexes Induced by Changes in Hydrophilicity and Electrostatic Ef. Chemistry 2013; 19:13182-92. [DOI: 10.1002/chem.201301547] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Indexed: 12/18/2022]
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Chung CYS, Yam VWW. Selective label-free detection of G-quadruplex structure of human telomere by emission spectral changes in visible-and-NIR region under physiological condition through the FRET of a two-component PPE-SO3−–Pt(ii) complex ensemble with Pt⋯Pt, electrostatic and π–π interactions. Chem Sci 2013. [DOI: 10.1039/c2sc20897k] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
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Chung CYS, Li SPY, Louie MW, Lo KKW, Yam VWW. Induced self-assembly and disassembly of water-soluble alkynylplatinum(ii) terpyridyl complexes with “switchable” near-infrared (NIR) emission modulated by metal–metal interactions over physiological pH: demonstration of pH-responsive NIR luminescent probes in cell-imaging studies. Chem Sci 2013. [DOI: 10.1039/c3sc50196e] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
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Chung CYS, Yam VWW. Induced Self-Assembly and Förster Resonance Energy Transfer Studies of Alkynylplatinum(II) Terpyridine Complex Through Interaction With Water-Soluble Poly(phenylene ethynylene sulfonate) and the Proof-of-Principle Demonstration of this Two-Component Ensemble for Selective Label-Free Detection of Human Serum Albumin. J Am Chem Soc 2011; 133:18775-84. [DOI: 10.1021/ja205996e] [Citation(s) in RCA: 135] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Clive Yik-Sham Chung
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
| | - Vivian Wing-Wah Yam
- Institute of Molecular Functional Materials (Areas of Excellence Scheme, University Grants Committee (Hong Kong)) and Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong, P.R. China
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Chung CYS, Chan KHY, Yam VWW. “Proof-of-principle” concept for label-free detection of glucose and α-glucosidase activity through the electrostatic assembly of alkynylplatinum(ii) terpyridyl complexes. Chem Commun (Camb) 2011; 47:2000-2. [DOI: 10.1039/c0cc04437g] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Hu Y, Chan KHY, Chung CYS, Yam VWW. Reversible thermo-responsive luminescent metallo-supramolecular triblock copolymers based on platinum(ii) terpyridyl chromophores with unusual aggregation behaviour and red-near-infrared (NIR) emission upon heating. Dalton Trans 2011; 40:12228-34. [DOI: 10.1039/c1dt10741k] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Yam VWW, Hu Y, Chan KHY, Chung CYS. Reversible pH- and solvent-responsive micelle-mediated self-assembly of platinum(ii) terpyridyl-based metallo-supramolecular diblock copolymers. Chem Commun (Camb) 2009:6216-8. [DOI: 10.1039/b911657e] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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