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Prasad K, de Vries EFJ, Elsinga PH, Dierckx RAJO, van Waarde A. Allosteric Interactions between Adenosine A 2A and Dopamine D 2 Receptors in Heteromeric Complexes: Biochemical and Pharmacological Characteristics, and Opportunities for PET Imaging. Int J Mol Sci 2021; 22:ijms22041719. [PMID: 33572077 PMCID: PMC7915359 DOI: 10.3390/ijms22041719] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 12/17/2022] Open
Abstract
Adenosine and dopamine interact antagonistically in living mammals. These interactions are mediated via adenosine A2A and dopamine D2 receptors (R). Stimulation of A2AR inhibits and blockade of A2AR enhances D2R-mediated locomotor activation and goal-directed behavior in rodents. In striatal membrane preparations, adenosine decreases both the affinity and the signal transduction of D2R via its interaction with A2AR. Reciprocal A2AR/D2R interactions occur mainly in striatopallidal GABAergic medium spiny neurons (MSNs) of the indirect pathway that are involved in motor control, and in striatal astrocytes. In the nucleus accumbens, they also take place in MSNs involved in reward-related behavior. A2AR and D2R co-aggregate, co-internalize, and co-desensitize. They are at very close distance in biomembranes and form heteromers. Antagonistic interactions between adenosine and dopamine are (at least partially) caused by allosteric receptor–receptor interactions within A2AR/D2R heteromeric complexes. Such interactions may be exploited in novel strategies for the treatment of Parkinson’s disease, schizophrenia, substance abuse, and perhaps also attention deficit-hyperactivity disorder. Little is known about shifting A2AR/D2R heteromer/homodimer equilibria in the brain. Positron emission tomography with suitable ligands may provide in vivo information about receptor crosstalk in the living organism. Some experimental approaches, and strategies for the design of novel imaging agents (e.g., heterobivalent ligands) are proposed in this review.
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Affiliation(s)
- Kavya Prasad
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
| | - Erik F. J. de Vries
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Philip H. Elsinga
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
| | - Rudi A. J. O. Dierckx
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Department of Diagnostic Sciences, Ghent University Faculty of Medicine and Health Sciences, C.Heymanslaan 10, 9000 Gent, Belgium
| | - Aren van Waarde
- Department of Nuclear Medicine and Molecular Imaging, University Medical Center Groningen, University of Groningen, Hanzeplein 1, 9713GZ Groningen, The Netherlands; (E.F.J.d.V.); (P.H.E.); (R.A.J.O.D.)
- Correspondence: (K.P.); (A.v.W.); Tel.: +31-50-3613215
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Jurgielewicz P, Harmsen S, Wei E, Bachmann MH, Ting R, Aras O. New imaging probes to track cell fate: reporter genes in stem cell research. Cell Mol Life Sci 2017; 74:4455-4469. [PMID: 28674728 DOI: 10.1007/s00018-017-2584-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2017] [Revised: 06/06/2017] [Accepted: 06/26/2017] [Indexed: 01/09/2023]
Abstract
Cell fate is a concept used to describe the differentiation and development of a cell in its organismal context over time. It is important in the field of regenerative medicine, where stem cell therapy holds much promise but is limited by our ability to assess its efficacy, which is mainly due to the inability to monitor what happens to the cells upon engraftment to the damaged tissue. Currently, several imaging modalities can be used to track cells in the clinical setting; however, they do not satisfy many of the criteria necessary to accurately assess several aspects of cell fate. In recent years, reporter genes have become a popular option for tracking transplanted cells, via various imaging modalities in small mammalian animal models. This review article examines the reporter gene strategies used in imaging modalities such as MRI, SPECT/PET, Optoacoustic and Bioluminescence Imaging. Strengths and limitations of the use of reporter genes in each modality are discussed.
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Affiliation(s)
- Piotr Jurgielewicz
- Pennsylvania State University College of Medicine, Hershey, PA, 17033, USA
| | - Stefan Harmsen
- Department of Pediatrics, Stanford University, Stanford, CA, 94305, USA
| | | | | | - Richard Ting
- Department of Radiology, Weill Cornell Medicine, Weill Cornell Medical College, New York, NY, 10065, USA
| | - Omer Aras
- Department of Radiology, Memorial Sloan Kettering Cancer Center, 300 East 66th Street, Suite 1511, New York, NY, 10065, USA.
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Abstract
Chimaeric antigen receptor (CAR) therapy is entering the mainstream for the treatment of CD19(+)cancers. As is does we learn more about resistance to therapy and the role, risks and management of toxicity. In solid tumour CAR therapy research the route to the clinic is less smooth with a wealth of challenges facing translating this, potentially hugely valuable, therapeutic option for patients. As we strive to understand our successes, and navigate the challenges, having a clear understanding of how adoptively transferred CAR-T-cells behavein vivoand in human trials is invaluable. Harnessing reporter gene imaging to enable detection and tracking of small numbers of CAR-T-cells after adoptive transfer is one way by which we can accomplish this. The compatibility of certain reporter gene systems with tracers available routinely in the clinic makes this approach highly useful for future appraisal of CAR-T-cell success in humans.
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Schönitzer V, Haasters F, Käsbauer S, Ulrich V, Mille E, Gildehaus FJ, Carlsen J, Pape M, Beck R, Delker A, Böning G, Mutschler W, Böcker W, Schieker M, Bartenstein P. In vivo mesenchymal stem cell tracking with PET using the dopamine type 2 receptor and 18F-fallypride. J Nucl Med 2014; 55:1342-7. [PMID: 25024426 DOI: 10.2967/jnumed.113.134775] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [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: 11/12/2013] [Accepted: 06/02/2014] [Indexed: 12/14/2022] Open
Abstract
UNLABELLED Human mesenchymal stem cells (hMSCs) represent a promising treatment approach for tissue repair and regeneration. However, little is known about the underlying mechanisms and the fate of the transplanted cells. The objective of the presented work was to determine the feasibility of PET imaging and in vivo monitoring after transplantation of dopamine type 2 receptor-expressing cells. METHODS An hMSC line constitutively expressing a mutant of the dopamine type 2 receptor (D2R80A) was generated by lentiviral gene transfer. D2R80A messenger RNA expression was confirmed by reverse transcriptase-polymerase chain reaction. Localization of the transmembrane protein was analyzed by confocal fluorescence microscopy. The stem cell character of transduced hMSCs was investigated by adipogenic and osteogenic differentiation. Migration capacity was assessed by scratch assays in time-lapse imaging. In vitro specific binding of ligands was tested by fluorescence-activated cell sorting analysis and by radioligand assay using (18)F-fallypride. Imaging of D2R80A overexpressing hMSC transplanted into athymic rats was performed by PET using (18)F-fallypride. RESULTS hMSCs showed long-term overexpression of D2R80A. As expected, the fluorescence signal suggested the primary localization of the protein in the membrane of the transduced cells. hMSC and D2R80A retained their stem cell character demonstrated by their osteogenic and adipogenic differentiation capacity and their proliferation and migration behavior. For in vitro hMSCs, at least 90% expressed the D2R80A transgene and hMSC-D2R80A showed specific binding of (18)F-fallypride. In vivo, a specific signal was detected at the transplantation site up to 7 d by PET. CONCLUSION The mutant of the dopamine type 2 receptor (D2R80A) is a potent reporter to detect hMSCs by PET in vivo.
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Affiliation(s)
- Veronika Schönitzer
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Florian Haasters
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Stefanie Käsbauer
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Veronika Ulrich
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Erik Mille
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Franz Josef Gildehaus
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Janette Carlsen
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Manuela Pape
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Roswitha Beck
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Andreas Delker
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Guido Böning
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Wolf Mutschler
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Wolfgang Böcker
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Matthias Schieker
- Department of Surgery, Experimental Surgery, and Regenerative Medicine, Ludwig-Maximilians-University Munich, Munich, Germany; and
| | - Peter Bartenstein
- Department of Nuclear Medicine, Ludwig-Maximilians-University Munich, Munich, Germany
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Wu B, Khong PL, Chan T. Automatic detection and classification of nasopharyngeal carcinoma on PET/CT with support vector machine. Int J Comput Assist Radiol Surg 2012; 7:635-46. [PMID: 22215412 DOI: 10.1007/s11548-011-0669-y] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Accepted: 12/19/2011] [Indexed: 11/28/2022]
Abstract
PURPOSE Positron emission tomography/computed tomography (PET/CT) has established values for imaging of head and neck cancers, including the nasopharyngeal carcinoma (NPC), utilizing both morphologic and functional information. In this paper, we introduce a computerized system for automatic detection of NPC, targeting both the primary tumor and regional nodal metastasis, on PET/CT. METHODS Candidate lesions were extracted based on the features from both PET and CT images and a priori knowledge of anatomical features and subsequently classified by a support vector machine algorithm. The system was validated with 25 PET/CT examinations from 10 patients suffering from NPC. Lesions manually contoured by experienced radiologists were used as the gold standard. RESULTS Results showed that the system successfully identified all 53 hypermetabolic lesions larger than 1 cm in size and excluded normal physiological uptake in brown fat, muscles, bone marrow, brain, and salivary glands. CONCLUSION The system combined both imaging features and a priori clinical knowledge for classification between pathological and physiological uptake. Preliminary results showed that the system was highly accurate and promising for adoption in clinical use.
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Affiliation(s)
- Bangxian Wu
- Department of Diagnostic Radiology, The University of Hong Kong, Room 406, Block K, Queen Mary Hospital, Pok Fu Lam, Hong Kong
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Aung W, Hasegawa S, Koshikawa-Yano M, Tsuji AB, Sogawa C, Sudo H, Sugyo A, Koizumi M, Furukawa T, Saga T. Noninvasive assessment of regulable transferred-p53 gene expression and evaluation of therapeutic response with FDG-PET in tumor model. Gene Ther 2010; 17:1142-51. [PMID: 20445579 DOI: 10.1038/gt.2010.70] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2009] [Revised: 02/23/2010] [Accepted: 03/18/2010] [Indexed: 01/18/2023]
Abstract
The use of tumor-suppressor gene p53 as an anticancer therapeutic has been vigorously investigated. However, progress has met with limited success to date. Some major drawbacks are the difficulty in achieving controllable and efficient gene transfer as well as in analyzing the transferred gene expression in real time and the treatment response in a timely manner. Thus, development of novel gene transfer vector with a regulative gene expression system coupled with the reporter gene, by which transgene can be monitored simultaneously, is critical. Moreover, noninvasive imaging-based assessment of the therapeutic response to exogenous wild-type p53 gene transfer is crucial for refining treatment protocols. In this study, as a simple preclinical model, we constructed a doxycycline-regulated bidirectional vector harboring a reporter gene encoding red fluorescence protein and p53. Then, we determined the controllable and simultaneously coordinated expression of both proteins and the p53-mediated anticancer effects in vitro and in vivo. Next, we observed that cells or tumors with induced p53 overexpression exhibited decreased uptake of [(14)C]FDG in cellular assay and [(18)F]FDG in positron emission tomography (PET) imaging. Thus, by coupling with bidirectional vector, controllable p53 transfer was achieved and the capability of fluoro-2-deoxy-D-glucose (FDG)-PET to assess the therapeutic response to p53 gene therapy was evidently confirmed, which may have an impact on the improvement of p53 gene therapy.
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Affiliation(s)
- W Aung
- Diagnostic Imaging Group, Molecular Imaging Center, National Institute of Radiological Sciences, Chiba, Japan.
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Abstract
Cell based therapies such as stem cell therapies or adoptive immunotherapies are currently being explored as a potential treatment for a variety of diseases such as Parkinson's disease, diabetes or cancer. However, quantitative and qualitative evaluation of adoptively transferred cells is indispensable for monitoring the efficiency of the treatment. Current approaches mostly analyze transferred cells from peripheral blood, which cannot assess whether transferred cells actually home to and stay in the targeted tissue. Using cell-labeling methods such as direct labeling or transfection with a marker gene in conjunction with various imaging modalities (MRI, optical or nuclear imaging), labeled cells can be followed in vivo in real-time, and their accumulation as well as function in vivo can be monitored and quantified accurately. This method is usually referred to as "cell tracking" or "cell trafficking" and is also being applied in basic biological sciences, exemplified in the evaluation of genes contributing to metastasis. This review focuses on principles of this promising methodology and explains various approaches by highlighting recent examples.
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Affiliation(s)
- J Grimm
- Dept. of Radiology, Memorial Sloan Kettering Cancer Center,1275 York Avenue, New York, NY 10021, USA.
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Sakiyama Y, Hatano K, Tajima T, Kato T, Kawasumi Y, Suzuki M, Ito K. An atlas-based image registration method for dopamine receptor imaging with PET in rats. Ann Nucl Med 2007; 21:455-62. [DOI: 10.1007/s12149-007-0049-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2007] [Accepted: 06/11/2007] [Indexed: 10/22/2022]
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Ottobrini L, Ciana P, Moresco R, Lecchi M, Belloli S, Martelli C, Todde S, Fazio F, Gambhir SS, Maggi A, Lucignani G. Development of a bicistronic vector for multimodality imaging of estrogen receptor activity in a breast cancer model: preliminary application. Eur J Nucl Med Mol Imaging 2007; 35:365-78. [PMID: 17926035 DOI: 10.1007/s00259-007-0578-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 08/28/2007] [Indexed: 11/30/2022]
Abstract
PURPOSE The aim of this study was to develop a cellular model for the concurrent imaging of reporter genes expression by using positron emission tomography (PET) and bioluminescence imaging (BLI) for the assessment of estrogen receptor activity in vivo in a breast cancer model. METHODS Two reporters were chosen: a mutated form of the dopaminergic D2 receptor (D(2)R80A) for PET imaging, and the Firefly Luciferase for BLI. The presence of an IRES sequence between the two reporters ensured the coordinated expression driven by the same regulatory sequence containing an estrogen responsive element (ERE). To prevent chromatin effects on reporter expression, the construct was flanked by insulator sequences (Matrix Attachment Region, MAR). RESULTS In vitro studies showed that the vector was efficient in coordinating the expression of the two genes. Moreover, stably transfected cells implanted in recipient animals maintained their capacity to express the reporters and react to systemic treatments permitting the in vivo study of ERs activity by PET and BLI imaging. In vitro expression analysis after long-term treatments showed different behaviour of the two reporter proteins in monitoring estrogen-dependent transcription outlining the importance of multi-reporter systems. With this model, PET and BLI can be applied to the concurrent evaluation of gene expression induced by estrogen and its analogues by using a bicistronic construct. CONCLUSION The combined features of rapid, sensitive, sequential BLI and tomographic and quantitative PET imaging will allow the use of this strategy for the in vivo evaluation of molecular processes also for pharmacodynamic studies.
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Affiliation(s)
- Luisa Ottobrini
- Institute of Radiological Sciences, University of Milan, Unit of Nuclear Medicine, Hospital San Paolo, Milan, Italy
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Abstract
Oncolytic viruses are being developed as anticancer drugs. They propagate selectively in tumor tissue and destroy it without causing excessive damage to normal non-cancerous tissues. When used as drugs, they must meet stringent criteria for safety and efficacy and be amenable to pharmacological study in human subjects. Specificity for neoplastic tissue is the key to safety, and this goal can be achieved through a variety of ingenious virus-engineering strategies. Antiviral immunity remains a significant barrier to the clinical efficacy of oncolytic viruses but this is being addressed by using novel immune-evasive delivery strategies and immunosuppressive drugs. Noninvasive pharmacokinetic monitoring is facilitated by engineering marker genes into the viral genome. Clinical data on the pharmacokinetics of oncolytic viruses will be the key to accelerating their development and approval as effective anticancer drugs. This review introduces concepts relevant to the use of viruses as anticancer drugs, emphasizing targeting mechanisms as well as safety and efficacy issues that are currently limiting their clinical success.
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Affiliation(s)
- Stephen J Russell
- Molecular Medicine Program, Mayo Clinic College of Medicine, 200 First Street SW, Rochester, MN 55905, USA.
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Kummer C, Winkeler A, Dittmar C, Bauer B, Rueger MA, Rueckriem B, Heneka MT, Vollmar S, Wienhard K, Fraefel C, Heiss WD, Jacobs AH. Multitracer Positron Emission Tomographic Imaging of Exogenous Gene Expression Mediated by a Universal Herpes Simplex Virus 1 Amplicon Vector. Mol Imaging 2007. [DOI: 10.2310/7290.2007.00015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Affiliation(s)
- Christiane Kummer
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Alexandra Winkeler
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Claus Dittmar
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Bernd Bauer
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Maria Adele Rueger
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Benedikt Rueckriem
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Michael T. Heneka
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Stefan Vollmar
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Klaus Wienhard
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Cornel Fraefel
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Wolf-Dieter Heiss
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
| | - Andreas H. Jacobs
- From the Laboratory for Gene Therapy and Molecular Imaging, Max Planck-Institute for Neurological Research, Center for Molecular Medicine, and Department of Neurology, University of Cologne, Cologne, Germany
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Ji C, Zhang J, Cammack N, Sankuratri S. Development of a novel dual CCR5-dependent and CXCR4-dependent cell-cell fusion assay system with inducible gp160 expression. ACTA ACUST UNITED AC 2005; 11:65-74. [PMID: 16314403 DOI: 10.1177/1087057105282959] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In the current study, a novel coreceptor-specific cell-cell fusion (CCF) assay system is reported. The system possesses the following features: dual CCR5-dependent and CXCR4-dependent CCF assays, all stable cell lines, inducible expression of gp160 to minimize cytotoxicity, robust luciferase reporter, and 384-well format. These assays have been validated using various known HIV entry inhibitors targeting various stages of the HIV entry/fusion process, including fusion inhibitors, gp120 inhibitors, CCR5 antagonists, CCR5 antibodies, and CXCR4 antagonists. IC50 data generated from this assay system were well correlated to that from the antiviral assays. The effects of DMSO on this assay system were assessed, and a 2- to 3-fold increase in luciferase activity was observed in the presence of 0.05% to 2% DMSO. Although cell-cell fusion efficiency was enhanced, no changes in drug response kinetics for entry inhibitors were found in the presence of 0.1% or 0.5% DMSO. This assay system has been successfully used for the identification and characterization of thousands of CCR5 inhibitors.
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Affiliation(s)
- Changhua Ji
- Roche Palo Alto, 3411 Hillview Avenue, Palo Alto, CA 94304, USA.
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