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Transformable amyloid-beta mimetic peptide amphiphiles for lysosomal disruption in non-small cell lung cancer. Biomaterials 2021; 277:121078. [PMID: 34461458 PMCID: PMC9969961 DOI: 10.1016/j.biomaterials.2021.121078] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 08/11/2021] [Accepted: 08/18/2021] [Indexed: 12/24/2022]
Abstract
Non-small cell lung cancer (NSCLC) is the largest contributor to cancer mortality in the United States. Traditional chemotherapies are toxic and prone to the development of drug-resistance. Recently, several drug candidates were shown to induce lysosomal membrane permeabilization (LMP) in aggressive cancers. This has led to increased interest in lysosome dysregulation as a therapeutic target. However, approaches are needed to overcome two limitations of current lysosomal inhibitors: low specificity and potency. Here, we report the development of a transformable nanomaterial which is triggered to induce LMP of lysosomes in NSCLC. The nanomaterial consists of peptide amphiphiles, which self-assemble into nanoparticles, colocalize with the lysosome, and change conformation to nanofibrils due to lysosomal pH shift, which leads to the disruption of the lysosome, cell death, and cisplatin sensitization. We have found that this cell-penetrating transformable peptide nanoparticle (CPTNP) was cytotoxic to NSCLC cells in the low-micromolar range and it synergized cisplatin cytotoxicity four-fold. Moreover, we demonstrate CPTNP's promising antitumor effect in mouse xenograft models with limited toxicity when given in combination with low dose cisplatin chemotherapy. This is the first example of enhanced LMP via transformable peptide nanomaterial and offers a promising new strategy for cancer therapy.
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Gkika K, Noorani S, Walsh N, Keyes TE. Os(II)-Bridged Polyarginine Conjugates: The Additive Effects of Peptides in Promoting or Preventing Permeation in Cells and Multicellular Tumor Spheroids. Inorg Chem 2021; 60:8123-8134. [PMID: 33978399 PMCID: PMC8277133 DOI: 10.1021/acs.inorgchem.1c00769] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Indexed: 12/05/2022]
Abstract
The preparation of two polyarginine conjugates of the complex Os(II) [bis-(4'-(4-carboxyphenyl)-2,2':6',2″-terpyridine)] [Os-(Rn)2]x+ (n = 4 and 8; x = 10 and 18) is reported, to explore whether the R8 peptide sequence that promotes cell uptake requires a contiguous amino acid sequence for membrane permeation or if this can be accomplished in a linearly bridged structure with the additive effect of shorter peptide sequences. The conjugates exhibit NIR emission centered at 754 nm and essentially oxygen-insensitive emission with a lifetime of 89 ns in phosphate-buffered saline. The uptake, distribution, and cytotoxicity of the parent complex and peptide derivatives were compared in 2D cell monolayers and a three-dimensional (3D) multicellular tumor spheroid (MCTS) model. Whereas, the bis-octaarginine sequences were impermeable to cells and spheroids, and the bis-tetraarginine conjugate showed excellent cellular uptake and accumulation in two 2D monolayer cell lines and remarkable in-depth penetration of 3D MCTSs of pancreatic cancer cells. Overall, the data indicates that cell permeability can be promoted via non-contiguous sequences of arginine residues bridged across the metal centre.
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Affiliation(s)
- Karmel
S. Gkika
- School
of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland
| | - Sara Noorani
- School
of Biotechnology, National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Naomi Walsh
- School
of Biotechnology, National Institute for Cellular Biotechnology, Dublin City University, Dublin 9, Ireland
| | - Tia E. Keyes
- School
of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Dublin 9, Ireland
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Gayraud F, Klußmann M, Neundorf I. Recent Advances and Trends in Chemical CPP-Drug Conjugation Techniques. Molecules 2021; 26:molecules26061591. [PMID: 33805680 PMCID: PMC7998868 DOI: 10.3390/molecules26061591] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 03/08/2021] [Accepted: 03/10/2021] [Indexed: 12/30/2022] Open
Abstract
This review summarizes recent developments in conjugation techniques for the synthesis of cell-penetrating peptide (CPP)–drug conjugates targeting cancer cells. We will focus on small organic molecules as well as metal complexes that were used as cytostatic payloads. Moreover, two principle ways of coupling chemistry will be discussed direct conjugation as well as the use of bifunctional linkers. While direct conjugation of the drug to the CPP is still popular, the use of bifunctional linkers seems to gain increasing attention as it offers more advantages related to the linker chemistry. Thus, three main categories of linkers will be highlighted, forming either disulfide acid-sensitive or stimuli-sensitive bonds. All techniques will be thoroughly discussed by their pros and cons with the aim to help the reader in the choice of the optimal conjugation technique that might be used for the synthesis of a given CPP–drug conjugate
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Śmiłowicz D, Metzler-Nolte N. Bioconjugates of Co(III) complexes with Schiff base ligands and cell penetrating peptides: Solid phase synthesis, characterization and antiproliferative activity. J Inorg Biochem 2020; 206:111041. [PMID: 32120161 DOI: 10.1016/j.jinorgbio.2020.111041] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 02/17/2020] [Accepted: 02/17/2020] [Indexed: 10/25/2022]
Abstract
In this work we synthesized a chelating Schiff base by a single condensation of salicylaldehyde with 3,4-diamino benzoic acid (1). This ligand was used further for complexation to CoCl2·6H2O under nitrogen. In the next step, three six-coordinate Co(III) complexes were synthesized by coordinating this complex with imidazole (2), 2-methyimidazole (3) and N-Boc-l-histidine methyl ester (4) (Boc: tert.-butoxycarbonyl) in axial positions with simultaneous oxidation of Co(II) to Co(III) under ambient environment. All Co(III) complexes were characterized by multinuclear NMR spectroscopy (1H, 13C and 59Co NMR), FT-IR, mass spectrometry and HPLC. The Co(III) complexes were conjugated to three different cell penetrating peptides: FFFF (P1), RRRRRRRRRGAL (P2) and FFFFRRRRRRRRRGAL (P3). Standard solid-phase peptide chemistry was used for the synthesis of cell penetrating peptides. Coupling of N-terminal peptides with the cobalt complexes, possessing a carboxylic group on the tetradentate Schiff base ligand, afforded Co(III)-peptide bioconjugates, which were purified by semi-preparative HPLC and characterized by analytical HPLC and mass spectrometry. The antiproliferative activity of the synthesized compounds was studied against different human tumour cell lines: lung cancer A549, liver cancer HepG2 and normal human fibroblasts GM5657T, in comparison with the activity of cisplatin as a reference drug. The bioconjugate 21 containing the Co complex 4 and the combined phenylalanine and polyarginine cell penetrating sequence P3 shows better activity against the liver cancer line HepG2 than the parent Co(III) complex 4.
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Affiliation(s)
- Dariusz Śmiłowicz
- Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany
| | - Nils Metzler-Nolte
- Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany.
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Wang R, Chen H, Yan W, Zheng M, Zhang T, Zhang Y. Ferrocene-containing hybrids as potential anticancer agents: Current developments, mechanisms of action and structure-activity relationships. Eur J Med Chem 2020; 190:112109. [PMID: 32032851 DOI: 10.1016/j.ejmech.2020.112109] [Citation(s) in RCA: 97] [Impact Index Per Article: 24.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2020] [Revised: 01/29/2020] [Accepted: 01/29/2020] [Indexed: 12/11/2022]
Abstract
Cancer is one of the most fatal threatens to human health throughout the world. The major challenges in the control and eradication of cancers are the continuous emergency of drug-resistant cancer and the low specificity of anticancer agents, creating an urgent need to develop novel anticancer agents. Organometallic compounds especially ferrocene derivatives possess remarkable structural and mechanistic diversity, inherent stability towards air, heat and light, low toxicity, low cost, reversible redox, ligand exchange, and catalytic properties, making them promising drug candidates for cancer therapy. Ferrocifen, a ferrocene-phenol hybrid, has demonstrated promising anticancer properties on drug-resistant cancers. Currently, Ferrocifen is in pre-clinical trial against cancers. Obviously, ferrocene moiety is a useful template for the development of novel anticancer agents. This review will provide an overview of ferrocene-containing hybrids with potential application in the treatment of cancers covering articles published between 2010 and 2020. The mechanisms of action, the critical aspects of design and structure-activity relationships are also discussed.
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Affiliation(s)
- Ruo Wang
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, China.
| | - Huahong Chen
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Weitao Yan
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Mingwen Zheng
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Tesen Zhang
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, China
| | - Yaohuan Zhang
- College of Chemistry, Fuzhou University, Fuzhou, Fujian, 350116, China
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Han Y, Da Y, Yu M, Cheng Y, Wang X, Xiong J, Guo G, Li Y, Jiang X, Cai X. Protein labeling approach to improve lysosomal targeting and efficacy of antibody–drug conjugates. Org Biomol Chem 2020; 18:3229-3233. [DOI: 10.1039/d0ob00265h] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
An anti-EGFR nanobody was labeled at the C-terminus with a lysosome-sorting NPGY (Asn-Pro-Gly-Tyr) motifviasortase-mediated ligation to enhance the clathrin-mediated endocytosis.
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Affiliation(s)
- Ying Han
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Yifan Da
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Mingjia Yu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering
- Beijing University of Chemical Technology
- Beijing
- China
| | - Yaping Cheng
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Xin Wang
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Jiale Xiong
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Guoying Guo
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Yan Li
- School of Engineering
- Sun Yat-sen University
- Guangzhou
- China
| | - Xianxing Jiang
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
| | - Xiaoqing Cai
- School of Pharmaceutical Sciences
- Sun Yat-sen University
- Guangzhou
- China
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Śmiłowicz D, Kogelheide F, Stapelmann K, Awakowicz P, Metzler-Nolte N. Study on Chemical Modifications of Glutathione by Cold Atmospheric Pressure Plasma (Cap) Operated in Air in the Presence of Fe(II) and Fe(III) Complexes. Sci Rep 2019; 9:18024. [PMID: 31792236 PMCID: PMC6888970 DOI: 10.1038/s41598-019-53538-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2019] [Accepted: 10/23/2019] [Indexed: 01/21/2023] Open
Abstract
Cold atmospheric pressure plasma is an attractive new research area in clinical trials to treat skin diseases. However, the principles of plasma modification of biomolecules in aqueous solutions remain elusive. It is intriguing how reactive oxygen and nitrogen species (RONS) produced by plasma interact on a molecular level in a biological environment. Previously, we identified the chemical effects of dielectric barrier discharges (DBD) on the glutathione (GSH) and glutathione disulphide (GSSG) molecules as the most important redox pair in organisms responsible for detoxification of intracellular reactive species. However, in the human body there are also present redox-active metals such as iron, which is the most abundant transition metal in healthy humans. In the present study, the time-dependent chemical modifications on GSH and GSSG in the presence of iron(II) and iron(III) complexes caused by a dielectric barrier discharge (DBD) under ambient conditions were investigated by IR spectroscopy, mass spectrometry and High Performance Liquid Chromatography (HPLC). HPLC chromatograms revealed one clean peak after treatment of both GSH and GSSH with the dielectric barrier discharge (DBD) plasma, which corresponded to glutathione sulfonic acid GSO3H. The ESI-MS measurements confirmed the presence of glutathione sulfonic acid. In our experiments, involving either iron(II) or iron(III) complexes, glutathione sulfonic acid GSO3H appeared as the main oxidation product. This is in sharp contrast to GSH/GSSG treatment with DBD plasma in the absence of metal ions, which gave a wild mixture of products. Also interesting, no nitrosylation of GSH/GSSG was oberved in the presence of iron complexes, which seems to indicate a preferential oxygen activation chemistry by this transition metal ion.
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Affiliation(s)
- Dariusz Śmiłowicz
- Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr University Bochum, 44780, Bochum, Germany
| | - Friederike Kogelheide
- Institute for Electrical Engineering and Plasma Technology, Ruhr University Bochum, 44780, Bochum, Germany
| | - Katharina Stapelmann
- Department of Nuclear Engineering, North Carolina State University, Raleigh, North Carolina, 27695, USA
| | - Peter Awakowicz
- Institute for Electrical Engineering and Plasma Technology, Ruhr University Bochum, 44780, Bochum, Germany
| | - Nils Metzler-Nolte
- Inorganic Chemistry I - Bioinorganic Chemistry, Ruhr University Bochum, 44780, Bochum, Germany.
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Xu J, Khan AR, Fu M, Wang R, Ji J, Zhai G. Cell-penetrating peptide: a means of breaking through the physiological barriers of different tissues and organs. J Control Release 2019; 309:106-124. [PMID: 31323244 DOI: 10.1016/j.jconrel.2019.07.020] [Citation(s) in RCA: 85] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 07/15/2019] [Indexed: 12/24/2022]
Abstract
The selective infiltration of cell membranes and tissue barriers often blocks the entry of most active molecules. This natural defense mechanism prevents the invasion of exogenous substances and limits the therapeutic value of most available molecules. Therefore, it is particularly important to find appropriate ways of membrane translocation and therapeutic agent delivery to its target site. Cell penetrating peptides (CPPs) are a group of short peptides harnessed in this condition, possessing a significant capacity for membrane transduction and could be exploited to transfer various biologically active cargoes into the cells. Since their discovery, CPPs have been employed for delivery of a wide variety of therapeutic molecules to treat various disorders including cranial nerve involvement, ocular inflammation, myocardial ischemia, dermatosis and cancer. The promising results of CPPs-derived therapeutics in various tumor models demonstrated a potential and worthwhile scope of CPPs in chemotherapy. This review describes the detailed description of CPPs and CPPs-assisted molecular delivery against various tissues and organs disorders. An emphasis is focused on summarizing the novel insights and achievements of CPPs in surmounting the natural membrane barriers during the last 5 years.
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Affiliation(s)
- Jiangkang Xu
- School of Pharmaceutical Sciences, Key Laboratory of Chemical Biology, Ministry of Education, Shandong University, Jinan 250012, China
| | - Abdur Rauf Khan
- School of Pharmaceutical Sciences, Key Laboratory of Chemical Biology, Ministry of Education, Shandong University, Jinan 250012, China
| | - Manfei Fu
- School of Pharmaceutical Sciences, Key Laboratory of Chemical Biology, Ministry of Education, Shandong University, Jinan 250012, China
| | - Rujuan Wang
- School of Pharmaceutical Sciences, Key Laboratory of Chemical Biology, Ministry of Education, Shandong University, Jinan 250012, China
| | - Jianbo Ji
- School of Pharmaceutical Sciences, Key Laboratory of Chemical Biology, Ministry of Education, Shandong University, Jinan 250012, China
| | - Guangxi Zhai
- School of Pharmaceutical Sciences, Key Laboratory of Chemical Biology, Ministry of Education, Shandong University, Jinan 250012, China.
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9
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Smiłowicz D, Metzler-Nolte N. Synthesis of monofunctional platinum(iv) carboxylate precursors for use in Pt(iv)-peptide bioconjugates. Dalton Trans 2018; 47:15465-15476. [PMID: 30334055 DOI: 10.1039/c8dt03082k] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Herein we present platinum(iv) bioconjugates with polyarginine peptides as prospective prodrug delivery systems. Asymmetrical platinum(iv) complexes 3 were obtained via oxidation of parent platinum(ii) complexes 2 with N-bromosuccinimide (NBS) in the presence of succinic anhydride. The combination of these two oxidation reagents furnishes the platinum(iv) environment with two different axial ligands, one of which bears a free carboxylic acid. All platinum(ii) and (iv) compounds were characterized by FT-IR, ESI-MS, HPLC, 1H-, 13C- and 195Pt-NMR. Standard solid-phase peptide chemistry was used for the synthesis of polyarginine (R9) peptides. Coupling of the platinum complexes with peptides N-terminally afforded peptide monoconjugates, which were purified by semi-preparative HPLC and characterized by analytical HPLC and ESI-MS. Platinum(iv)-peptide bioconjugates as well as platinum(ii) and platinum(iv) complexes were tested as cytotoxic agents against two different human cancer cell lines (MCF-7, HepG2) and normal human fibroblasts cell lines (GM5657T). Preliminary in vitro data showed that all platinum(iv) complexes exhibit lower activity than their platinum(ii) precursors towards most cell lines. Interestingly, in the case of HepG2 cells, the Pt(iv)-(R)9-G-A-L bioconjugate (4a) showed even higher activity compared to the non-targeting platinum(iv) parent compound.
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Affiliation(s)
- Dariusz Smiłowicz
- Inorganic Chemistry I - Bioinorganic Chemistry, Faculty of Chemistry and Biochemistry, Ruhr-University Bochum, Universitätsstraße 150, 44801 Bochum, Germany.
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10
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Wieczorek A, Błauż A, Makal A, Rychlik B, Plażuk D. Synthesis and evaluation of biological properties of ferrocenyl–podophyllotoxin conjugates. Dalton Trans 2017; 46:10847-10858. [DOI: 10.1039/c7dt02107k] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ferrocenyl–podophyllotoxin conjugates have been synthesised and their antiproliferative activity, influence on cell cycle, and interactions with tubulin were evaluated.
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Affiliation(s)
- Anna Wieczorek
- Department of Organic Chemistry
- Faculty of Chemistry
- University of Łódź
- 91-403 Łódź
- Poland
| | - Andrzej Błauż
- Cytometry Lab
- Department of Molecular Biophysics
- Faculty of Biology and Environmental Protection
- University of Łódź
- 90-236 Łódź
| | - Anna Makal
- University of Warsaw
- Biological and Chemical
- Research Centre
- 02-096 Warsaw
- Poland
| | - Błażej Rychlik
- Cytometry Lab
- Department of Molecular Biophysics
- Faculty of Biology and Environmental Protection
- University of Łódź
- 90-236 Łódź
| | - Damian Plażuk
- Department of Organic Chemistry
- Faculty of Chemistry
- University of Łódź
- 91-403 Łódź
- Poland
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Albada B, Metzler-Nolte N. Organometallic–Peptide Bioconjugates: Synthetic Strategies and Medicinal Applications. Chem Rev 2016; 116:11797-11839. [DOI: 10.1021/acs.chemrev.6b00166] [Citation(s) in RCA: 149] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Affiliation(s)
- Bauke Albada
- Laboratory of Organic Chemistry, Wageningen University & Research, Stippeneng 4, 6708 WE Wageningen, The Netherlands
| | - Nils Metzler-Nolte
- Inorganic
Chemistry I − Bioinorganic Chemistry, Ruhr University Bochum, Universitätsstrasse 150, 44780-D Bochum, Germany
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12
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Cerrato CP, Künnapuu K, Langel Ü. Cell-penetrating peptides with intracellular organelle targeting. Expert Opin Drug Deliv 2016; 14:245-255. [PMID: 27426871 DOI: 10.1080/17425247.2016.1213237] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
INTRODUCTION One of the major limiting steps in order to have an effective drug is the passage through one or more cell membranes to reach its site of action. To reach the action-site, the specific macromolecules are required to be delivered specifically to the cell compartment/organelle in their (pre)active form. Areas covered: In this review, we will discuss cell-penetrating peptides (CPPs) developed in the last decade to transport small RNA/DNA, plasmids, antibodies, and nanoparticles into specific sites of the cell. The article describes CPPs in complex with cargo molecules that target specific intracellular organelles and their potential for pharmacological or clinical use. Expert opinion: Organelle targeting is the ultimate goal to ensure selective delivery to the site of action in the cells. CPP technologies represent an important strategy to address drug delivery to specific intracellular compartments by covalent conjugation to targeting sequences, potentially enabling strategies to combat genomic diseases as well as infections, cancer, neurodegenerative and hereditary diseases. They have proven to be successful in delivering various therapeutic agents into cells however, further in vivo experiments and clinical trials are required to demonstrate the efficacy of this technology.
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Affiliation(s)
| | - Kadri Künnapuu
- b Laboratory of Molecular Biotechnology, Institute of Technology , University of Tartu , Tartu , Estonia
| | - Ülo Langel
- a Department of Neurochemistry , Stockholm University , Stockholm , Sweden.,b Laboratory of Molecular Biotechnology, Institute of Technology , University of Tartu , Tartu , Estonia
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Byrne A, Dolan C, Moriarty RD, Martin A, Neugebauer U, Forster RJ, Davies A, Volkov Y, Keyes TE. Osmium(II) polypyridyl polyarginine conjugate as a probe for live cell imaging; a comparison of uptake, localization and cytotoxicity with its ruthenium(II) analogue. Dalton Trans 2016. [PMID: 26197944 DOI: 10.1039/c5dt01833a] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A first investigation into the application of a luminescent osmium(ii) bipyridine complex to live cell imaging is presented. Osmium(ii) (bis-2,2-bipyridyl)-2(4-carboxylphenyl) imidazo[4,5f][1,10]phenanthroline was prepared and conjugated to octaarginine, a cell penetrating peptide. The photophysics, cell uptake and cytotoxicity of this osmium complex conjugate were performed and compared with its ruthenium analogue. Cell uptake and distribution of both ruthenium and osmium conjugates were very similar with rapid transmembrane transport of the osmium probe (complete within approx. 20 min) and dispersion throughout the cytoplasm and organelles. The near-infrared (NIR) emission of the osmium complex (λmax 726 nm) coincides well with the biological optical window and this facilitated luminescent and luminescence lifetime imaging of the cell which was well resolved from cell autofluorescence. The large Stokes shift of the emission also permitted resonance Raman mapping of the dye within CHO cells. Rather surprisingly, the osmium conjugate exhibited very low cytotoxicity when incubated both in the dark and under visible irradiation. This was attributed to the remarkable stability of this complex which was reflected by the complete absence of photo-bleaching of the complex even under extended continuous irradiation. In addition, when compared to its ruthenium analogue its luminescence was short-lived in water therefore rendering it insensitive to O2.
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Affiliation(s)
- Aisling Byrne
- School of Chemical Sciences, National Centre for Sensor Research, Dublin City University, Glasnevin, Dublin 9, Ireland.
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