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Production of human embryonic kidney 293T cells stably expressing C-X-C chemokine receptor type 4 (CXCR4) as a screening tool for anticancer lead compound targeting CXCR4. Life Sci 2022; 303:120661. [PMID: 35643380 DOI: 10.1016/j.lfs.2022.120661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Revised: 05/19/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022]
Abstract
AIM The C-X-C chemokine-receptor type 4 (CXCR4) is an emerging target for cancer drug discovery due to its high expression in cancer cells. The present study aimed to produce CXCR4 overexpressing HEK293T cells for a non-radioactive binding assay as a platform to identify drug candidates targeting CXCR4. MAIN METHODS HEK293T cells stably expressing human CXCR4 were constructed by transfection of CXCR4 plasmids from the human CXCR4 gene. The CXCR4 overexpressing HEK293T cells were obtained by fluorescence-activated sorting and verified by conducting the competition binding assay of a known CXCR4 inhibitor, AMD3100 (plerixafor), to determine the IC50 value against monoclonal anti-human CD184 (hCD184) antibody tagged with fluorescence probe, phycoerythrin (PE). The non-radioactive binding assay using CXCR4 overexpressing HEK293T cells and PE-anti hCD184 was applied as a platform for identifying the target of natural compounds that exhibited cytotoxicity against cancer cell lines. KEY FINDINGS The CXCR4 overexpressing HEK293T cells were produced with high expression (99.8%). The IC50 value of plerixafor determined by fluorescence tagged antibody-based competition assay using our developed cells agree with previously reported values using a radioligand binding assay. We observed no significant displacement of bound PE-anti-hCD184 by the test natural compounds which could be due to non-specific binding to other functional targets or organelles, low potency of the natural compounds, or binding to CXCR4 at deeper pockets. SIGNIFICANCE The verified non-radioactive binding assay can serve as an alternative screening tool for anticancer lead compounds targeting CXCR4 and an essential tool for proof of mechanism study in the drug discovery.
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Luyten K, Van Loy T, Cawthorne C, Deroose CM, Schols D, Bormans G, Cleeren F. D-Peptide-Based Probe for CXCR4-Targeted Molecular Imaging and Radionuclide Therapy. Pharmaceutics 2021; 13:pharmaceutics13101619. [PMID: 34683912 PMCID: PMC8537445 DOI: 10.3390/pharmaceutics13101619] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/16/2021] [Accepted: 09/29/2021] [Indexed: 12/29/2022] Open
Abstract
Positron emission tomography (PET) imaging of the C-X-C chemokine receptor 4 (CXCR4) with [68Ga]PentixaFor has intrinsic diagnostic value and is used to select patients for personalized CXCR4-targeted radionuclide therapy with its therapeutic radiopharmaceutical companion [177Lu]PentixaTher. However, a CXCR4-targeting radiopharmaceutical labeled with fluorine-18 is still of high value due to its favorable characteristics over gallium-68. Furthermore, clinical results with [177Lu]PentixaTher are promising, but there is still room for improvement regarding pharmacokinetics and dosimetry profile. Therefore, this study aimed to develop innovative CXCR4-targeting radiopharmaceuticals, both for diagnostic and therapeutic purposes, starting from a D-amino acid-based peptide probe (DV1-k-(DV3)) that conserves high CXCR4 binding affinity after radiolabeling. AlF-NOTA-DV1-k-(DV3) showed similar in vitro binding affinity to human CXCR4 (hCXCR4) compared to [natGa]PentixaFor (half-maximal inhibitory concentration (IC50): 5.3 ± 0.9 nM and 8.6 ± 1.1 nM, respectively) and also binds to murine CXCR4 (mCXCR4) (IC50: 33.4 ± 13.5 nM) while [natGa]PentixaFor is selective for hCXCR4 (IC50 > 1000 nM for mCXCR4). Both the diagnostic radiotracers based on the DV1-k-(DV3) vector platform, [18F]AlF-NOTA-DV1-k-(DV3) and [68Ga]Ga-DOTA-DV1-k-(DV3), and their therapeutic companion [177Lu]Lu-DOTA-DV1-k-(DV3) were successfully produced in high yield, demonstrated high in vitro and in vivo stability, and have the same favorable pharmacokinetic profile. Furthermore, in wild-type mice and a hCXCR4-expressing tumor model, [18F]AlF-NOTA-DV1-k-(DV3) shows CXCR4-specific targeting in mCXCR4-expressing organs such as liver (mean standardized uptake value (SUVmean) 8.2 ± 1.0 at 75 min post-injection (p.i.)), spleen (SUVmean 2.5 ± 1.0 at 75 min p.i.), and bone (SUVmean 0.4 ± 0.1 at 75 min p.i., femur harboring bone marrow) that can be blocked with the CXCR4 antagonist AMD3100. However, in a hCXCR4-expressing tumor model, tumor uptake of [18F]AlF-NOTA-DV1-k-(DV3) was significantly lower (SUVmean 0.6 ± 0.2) compared to [68Ga]PentixaFor (SUVmean 2.9). This might be explained by the high affinity of [18F]AlF-NOTA-DV1-k-(DV3) toward both mCXCR4 and hCXCR4. High mCXCR4 expression in mouse liver results in a large fraction of [18F]AlF-NOTA-DV1-k-(DV3) that is sequestered to the liver, resulting despite its similar in vitro affinity for hCXCR4, in lower tumor accumulation compared to [68Ga]PentixaFor. As CXCR4 is not expressed in healthy human liver, the findings in mice are not predictive for the potential clinical performance of this novel class of CXCR4-targeting radiotracers. In conclusion, the DV1-k-(DV3) scaffold is a promising vector platform for translational CXCR4-directed research.
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Affiliation(s)
- Kaat Luyten
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium; (K.L.); (G.B.)
| | - Tom Van Loy
- Laboratory of Virology and Chemotherapy, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium; (T.V.L.); (D.S.)
| | - Christopher Cawthorne
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, 3000 Leuven, Belgium; (C.C.); (C.M.D.)
| | - Christophe M. Deroose
- Nuclear Medicine and Molecular Imaging, Department of Imaging and Pathology, KU Leuven, 3000 Leuven, Belgium; (C.C.); (C.M.D.)
| | - Dominique Schols
- Laboratory of Virology and Chemotherapy, Department of Microbiology, Immunology and Transplantation, KU Leuven, 3000 Leuven, Belgium; (T.V.L.); (D.S.)
| | - Guy Bormans
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium; (K.L.); (G.B.)
| | - Frederik Cleeren
- Laboratory for Radiopharmaceutical Research, Department of Pharmaceutical and Pharmacological Sciences, KU Leuven, 3000 Leuven, Belgium; (K.L.); (G.B.)
- Correspondence:
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Adlere I, Caspar B, Arimont M, Dekkers S, Visser K, Stuijt J, de Graaf C, Stocks M, Kellam B, Briddon S, Wijtmans M, de Esch I, Hill S, Leurs R. Modulators of CXCR4 and CXCR7/ACKR3 Function. Mol Pharmacol 2019; 96:737-752. [DOI: 10.1124/mol.119.117663] [Citation(s) in RCA: 38] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Accepted: 09/14/2019] [Indexed: 02/06/2023] Open
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Zhu S, Meng Q, Schooley RT, An J, Xu Y, Huang Z. Structural and Biological Characterizations of Novel High-Affinity Fluorescent Probes with Overlapped and Distinctive Binding Regions on CXCR4. Molecules 2019; 24:molecules24162928. [PMID: 31412600 PMCID: PMC6720714 DOI: 10.3390/molecules24162928] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2019] [Revised: 08/09/2019] [Accepted: 08/10/2019] [Indexed: 01/25/2023] Open
Abstract
CXC-type chemokine receptor 4 (CXCR4) is well known as a co-receptor for cellular entry and infection of human immunodeficiency virus type 1 (HIV-1). As an important member of the G protein-coupled receptor (GPCR) family, CXCR4 also mediates a variety of cellular processes and functions, such as cell chemotaxis, proliferation, and calcium signal transductions. Identification and characterization of molecular ligands or probes of CXCR4 have been an intensive area of investigations as such ligands or probes are of significant clinical values for the studies and treatments of HIV-1 infection and other human diseases mediated by the receptor. The crystal structures of CXCR4 in complex with different ligands have revealed two distinctive binding regions or subpockets. Thus, understanding the interactions of diverse ligands with these distinctive CXCR4 binding regions has become vital for elucidating the relationship between binding modes and biological mechanisms of ligand actions. Peptidic CVX15 is the only ligand that has been validated to bind one of these distinctive binding regions (or so called the major subpocket) of CXCR4. Therefore, in this study, we developed an efficient probe system including two high-affinity peptidic fluorescent probes, designated as FITC-CVX15 and FITC-DV1, with the aim of targeting distinctive CXCR4 subpockets. We conducted rational design and chemical characterization of the two CXCR4-specific probes and examined their application in biological experiments including competitive binding assays, flow cytometry analysis, and confocal imaging. Especially these two probes were applied in parallel CXCR4 competitive binding assays to detect and analyze potential binding modes of diverse CXCR4 ligands, together with molecular docking and simulations. Our results have indicated that these peptidic fluorescent probe systems provide novel ligand detecting tools, as well as present a new approach for analyzing distinctive binding modes of diverse CXCR4 ligands.
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Affiliation(s)
- Siyu Zhu
- School of Life Sciences, Tsinghua University, Beijing 100084, China
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Qian Meng
- School of Life Sciences, Tsinghua University, Beijing 100084, China
| | - Robert T Schooley
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Jing An
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA
| | - Yan Xu
- School of Life and Health Sciences, Chinese University of Hong Kong, Shenzhen 518172, China.
| | - Ziwei Huang
- School of Life Sciences, Tsinghua University, Beijing 100084, China.
- Department of Medicine, Division of Infectious Diseases and Global Public Health, School of Medicine, University of California San Diego, La Jolla, CA 92037, USA.
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Zhang C, Huang LS, Zhu R, Meng Q, Zhu S, Xu Y, Zhang H, Fang X, Zhang X, Zhou J, Schooley RT, Yang X, Huang Z, An J. High affinity CXCR4 inhibitors generated by linking low affinity peptides. Eur J Med Chem 2019; 172:174-185. [PMID: 30978562 DOI: 10.1016/j.ejmech.2019.03.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 03/20/2019] [Accepted: 03/23/2019] [Indexed: 01/04/2023]
Abstract
G-protein coupled receptors (GPCRs) are implicated in many diseases and attractive targets for drug discovery. Peptide fragments derived from protein ligands of GPCRs are commonly used as probes of GPCR function and as leads for drug development. However, these peptide fragments lack the structural integrity of their parent full-length protein ligands and often show low receptor affinity, which limits their research and therapeutic values. It remains a challenge to efficiently generate high affinity peptide inhibitors of GPCRs. We have investigated a combinational approach involving the synthetic covalent linkage of two low affinity peptide fragments to determine if the strategy can yield high affinity GPCR inhibitors. We examined this design approach using the chemokine receptor CXCR4 as a model of GPCR system. Here, we provide a proof of concept demonstration by designing and synthesizing two peptides, AR5 and AR6, that combine a peptide fragment derived from two viral ligands of CXCR4, vMIP-II and HIV-1 envelope glycoprotein gp120. AR5 and AR6 display nanomolar binding affinity, in contrast to the weak micromolar CXCR4 binding of each peptide fragment alone, and inhibit HIV-1 entry via CXCR4. Further studies were carried out for the representative peptide AR6 using western blotting and site-directed mutagenesis in conjunction with molecular dynamic simulation and binding free energy calculation to determine how the peptide interacts with CXCR4 and inhibits its downstream signaling. These results demonstrate that this combinational approach is effective for generating nanomolar active inhibitors of CXCR4 and may be applicable to other GPCRs.
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Affiliation(s)
- Chaozai Zhang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China
| | - Lina S Huang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; College of Arts and Sciences, Cornell University, Ithaca, NY, 14853, USA
| | - Ruohan Zhu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Qian Meng
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Siyu Zhu
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; School of Life Sciences, Tsinghua University, Beijing, China
| | - Yan Xu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Huijun Zhang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA; School of Life Sciences, Tsinghua University, Beijing, China
| | - Xiong Fang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Xingquan Zhang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Jiao Zhou
- Nobel Institute of Biomedicine, Zhuhai, Guangdong, China
| | - Robert T Schooley
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA
| | - Xiaohong Yang
- School of Pharmaceutical Sciences, Jilin University, Changchun, 130021, China.
| | - Ziwei Huang
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA.
| | - Jing An
- Department of Medicine, Division of Infectious Diseases, School of Medicine, University of California San Diego, La Jolla, CA, 92037, USA.
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Zhu Y, Yang S, Wang J, Mao Y, Xu Y, An J, Huang Z. LC-MS/MS assay for the determination of a novel D-peptide antagonist of CXCR4 in rat plasma and its application to a preclinical pharmacokinetic study. J Pharm Biomed Anal 2018; 161:159-167. [PMID: 30165332 DOI: 10.1016/j.jpba.2018.08.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 08/13/2018] [Accepted: 08/15/2018] [Indexed: 11/25/2022]
Abstract
DV1 is a potent and selective D-peptide antagonist of CXCR4 and being developed as a novel drug candidate molecule. For preclinical pharmacokinetic study of DV1, we established an efficient and reliable liquid chromatography coupled to tandem mass spectrometric (LC-MS/MS) method for the assay of DV1 in rat plasma. Plasma samples were acidified by formic acid and then their protein content precipitated by acetonitrile. Sample separation was processed with a C18 column (4.6 mm × 100 mm, 5 μm) and washed by a water-acetonitrile gradient mobile phase containing 0.1% (v/v) formic acid at a flow rate of 0.4 mL/min. The mass spectrometer was operated in the multiple reaction monitoring mode and positive electrospray ionization. The assay had a good linearity over the range of 10-10000 ng/mL (r>0.998) for DV1. The adsorption of the peptide was diminished by organic additives during the quantitative procedure. The intra- and inter-day precision was 1.9-9.8% and the accuracy was 91.2-110.0%. No significant variation was observed under the optimized conditions. The recovery was above 52% with low matrix effects. The method was successfully applied to a pharmacokinetic study of DV1 after subcutaneous injection at dose of 10 mg/kg in rats. The half-life and AUCinf of DV1 were calculated as 8.7 h and 35,553 ng/mL·h, respectively. It is the first report on the quantitative analysis and pharmacokinetic characterization of a D-peptide targeted CXCR4, which should be useful for further preclinical studies and development of this and other peptide therapeutics.
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Affiliation(s)
- Yinsong Zhu
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Shu Yang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Juan Wang
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yujia Mao
- School of Life Sciences, Tsinghua University, Beijing, China
| | - Yan Xu
- School of Life Sciences, Tsinghua University, Beijing, China.
| | - Jing An
- Department of Medicine, University of California at San Diego, La Jolla, CA, USA.
| | - Ziwei Huang
- School of Life Sciences, Tsinghua University, Beijing, China; Department of Medicine, University of California at San Diego, La Jolla, CA, USA.
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Mao Y, Meng Q, Song P, Zhu S, Xu Y, Snyder EY, An J, Huang Z. Novel Bivalent and D-Peptide Ligands of CXCR4 Mobilize Hematopoietic Progenitor Cells to the Blood in C3H/HeJ Mice. Cell Transplant 2018; 27:1249-1255. [PMID: 29991278 PMCID: PMC6434473 DOI: 10.1177/0963689718784957] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The interaction of SDF-1α (also known as CXCL12) with the CXCR4 receptor plays a critical role in the retention of hematopoietic stem cells (HSCs) in bone marrow. The viral macrophage inflammatory protein-II (vMIP-II), a human herpesvirus-8 (HHV-8)-encoded viral chemokine, can bind the CXCR4 receptor and inhibit endogenous ligand-induced calcium responses and cell migration. Previously, we used the bivalent ligand approach to link synthetically two unnatural D-amino acid peptides derived from the N-terminus of vMIP-II (DV1 and DV3, respectively) to generate a dimeric peptide, DV1-K-(DV3) (also named HC4319), which shows very high affinity for CXCR4. Here, we studied the biological effects of this dimeric peptide, HC4319, and its monomeric counterpart, DV1, on SDF-1α-induced signaling in CXCR4- or CXCR7-transfected Chinese hamster ovary cells and mobilization of hematopoietic progenitor cells (HPCs) in C3H/HeJ mice using an HPC assay. HC4319 and DV1 inhibited significantly the phosphorylation of Akt and Erk, known to be downstream signaling events of CXCR4. This in vivo study in C3H/HeJ mice showed that HC4319 and DV-1 strongly induced rapid mobilization of granulocyte-macrophage colony-forming units (CFUs), erythrocyte burst-forming units, and granulocyte-erythrocyte-monocyte-megakaryocyte CFUs from the bone marrow to the blood. These results provide the first reported experimental evidence that bivalent and D-amino acid peptides derived from the N-terminus of vMIP-II are potent mobilizers of HPCs in C3H/HeJ mice and support the further development of such agents for clinical application.
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Affiliation(s)
- Yujia Mao
- 1 School of Life Sciences, Tsinghua University, Beijing, China
| | - Qian Meng
- 1 School of Life Sciences, Tsinghua University, Beijing, China
| | - Panpan Song
- 1 School of Life Sciences, Tsinghua University, Beijing, China
| | - Siyu Zhu
- 1 School of Life Sciences, Tsinghua University, Beijing, China
| | - Yan Xu
- 1 School of Life Sciences, Tsinghua University, Beijing, China.,2 Nobel Institute of Biomedicine, Zhuhai, Guangdong, China
| | - Evan Y Snyder
- 3 Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Jing An
- 2 Nobel Institute of Biomedicine, Zhuhai, Guangdong, China.,4 Division of Infectious Diseases, Department of Medicine, School of Medicine, University of California at San Diego, La Jolla, CA, USA
| | - Ziwei Huang
- 1 School of Life Sciences, Tsinghua University, Beijing, China.,4 Division of Infectious Diseases, Department of Medicine, School of Medicine, University of California at San Diego, La Jolla, CA, USA
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Use of Fluorescence Indicators in Receptor Ligands. Methods Mol Biol 2016; 1335:115-30. [PMID: 26260598 DOI: 10.1007/978-1-4939-2914-6_9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Fluorescence techniques can provide insights into the environment of fluorescence indicators incorporated within a ligand as it is bound to its receptor. Fluorescence indicators of different sizes and chemical characteristics can provide insights into the nature of the binding environment, the surrounding structures, and even into conformational changes associated with receptor activation. Methods for determining fluorescence spectral analysis, fluorescence quenching, fluorescence anisotropy, fluorescence lifetimes, and red edge excitation shifts of the ligand probes are described. The applications of these techniques to the CCK1 receptor occupied by alexa(488)-CCK and aladan-CCK, as examples of probes developed (1) by derivatization of an existing peptide and (2) by incorporation during peptide synthesis, are utilized as examples. These methods represent powerful tools to expand our understanding of the structure and molecular basis of ligand activation of G protein-coupled receptors.
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