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Uliassi E, Nikolic L, Bolognesi ML, Legname G. Therapeutic strategies for identifying small molecules against prion diseases. Cell Tissue Res 2022; 392:337-347. [PMID: 34989851 DOI: 10.1007/s00441-021-03573-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 12/22/2021] [Indexed: 01/10/2023]
Abstract
Prion diseases are fatal neurodegenerative disorders, for which there are no effective therapeutic and diagnostic agents. The main pathological hallmark has been identified as conformational changes of the cellular isoform prion protein (PrPC) to a misfolded isoform of the prion protein (PrPSc). Targeting PrPC and its conversion to PrPSc is still the central dogma in prion drug discovery, particularly in in silico and in vitro screening endeavors, leading to the identification of many small molecules with therapeutic potential. Nonetheless, multiple pathological targets are critically involved in the intricate pathogenesis of prion diseases. In this context, multi-target-directed ligands (MTDLs) emerge as valuable therapeutic approach for their potential to effectively counteract the complex etiopathogenesis by simultaneously modulating multiple targets. In addition, diagnosis occurs late in the disease process, and consequently a successful therapeutic intervention cannot be provided. In this respect, small molecule theranostics, which combine imaging and therapeutic properties, showed tremendous potential to cure and diagnose in vivo prion diseases. Herein, we review the major advances in prion drug discovery, from anti-prion small molecules identified by means of in silico and in vitro screening approaches to two rational strategies, namely MTDLs and theranostics, that have led to the identification of novel compounds with an expanded anti-prion profile.
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Affiliation(s)
- Elisa Uliassi
- Department of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro 6, Bologna, Italy
| | - Lea Nikolic
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore Di Studi Avanzati (SISSA), Trieste, Italy
| | - Maria Laura Bolognesi
- Department of Pharmacy and Biotechnology, University of Bologna, Via Belmeloro 6, Bologna, Italy.
| | - Giuseppe Legname
- Laboratory of Prion Biology, Department of Neuroscience, Scuola Internazionale Superiore Di Studi Avanzati (SISSA), Trieste, Italy.
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Mustazza C, Sbriccoli M, Minosi P, Raggi C. Small Molecules with Anti-Prion Activity. Curr Med Chem 2020; 27:5446-5479. [PMID: 31560283 DOI: 10.2174/0929867326666190927121744] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 08/08/2019] [Accepted: 09/05/2019] [Indexed: 01/20/2023]
Abstract
Prion pathologies are fatal neurodegenerative diseases caused by the misfolding of the physiological Prion Protein (PrPC) into a β-structure-rich isoform called PrPSc. To date, there is no available cure for prion diseases and just a few clinical trials have been carried out. The initial approach in the search of anti-prion agents had PrPSc as a target, but the existence of different prion strains arising from alternative conformations of PrPSc, limited the efficacy of the ligands to a straindependent ability. That has shifted research to PrPC ligands, which either act as chaperones, by stabilizing the native conformation, or inhibit its interaction with PrPSc. The role of transition-metal mediated oxidation processes in prion misfolding has also been investigated. Another promising approach is the indirect action via other cellular targets, like membrane domains or the Protein- Folding Activity of Ribosomes (PFAR). Also, new prion-specific high throughput screening techniques have been developed. However, so far no substance has been found to be able to extend satisfactorily survival time in animal models of prion diseases. This review describes the main features of the Structure-Activity Relationship (SAR) of the various chemical classes of anti-prion agents.
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Affiliation(s)
- Carlo Mustazza
- National Centre for Control and Evaluation of Medicines, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Marco Sbriccoli
- Department of Neurosciences, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Paola Minosi
- National Centre for Drug Research and Evaluation, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
| | - Carla Raggi
- National Centre for Control and Evaluation of Medicines, Italian National Institute of Health, Viale Regina Elena 299, 00161 Rome, Italy
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Padilla-Salinas R, Anderson R, Sakaniwa K, Zhang S, Nordeen P, Lu C, Shimizu T, Yin H. Discovery of Novel Small Molecule Dual Inhibitors Targeting Toll-Like Receptors 7 and 8. J Med Chem 2019; 62:10221-10244. [DOI: 10.1021/acs.jmedchem.9b01201] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Affiliation(s)
- Rosaura Padilla-Salinas
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Rachel Anderson
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Kentaro Sakaniwa
- Graduate School of Pharmaceuticals Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Shuting Zhang
- School of Pharmaceutical Sciences, Tsinghua University-Peking University Joint Center of Life Science, Tsinghua University, Beijing 100082, China
| | - Patrick Nordeen
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Chuanjun Lu
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
| | - Toshiyuki Shimizu
- Graduate School of Pharmaceuticals Sciences, The University of Tokyo, Tokyo 113-0033, Japan
| | - Hang Yin
- Department of Chemistry and Biochemistry and BioFrontiers Institute, University of Colorado Boulder, Boulder, Colorado 80309, United States
- School of Pharmaceutical Sciences, Tsinghua University-Peking University Joint Center of Life Science, Tsinghua University, Beijing 100082, China
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Abstract
Recent advances in understanding of the molecular biology of prion diseases and improved clinical diagnostic techniques might allow researchers to think about therapeutic trials in Creutzfeldt-Jakob disease (CJD) patients. Some attempts have been made in the past and various compounds have been tested in single case reports and patient series. Controlled trials are rare. However, in the past few years, it has been demonstrated that clinical trials are feasible. The clinicians might face several specific problems when evaluating the efficacy of the drug in CJD, such as rareness of the disease, lack of appropriate preclinical tests and heterogeneous clinical presentation in humans. These problems have to be carefully addressed in future.
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Affiliation(s)
- Saima Zafar
- Clinical Dementia Center and German Center for Neurodegenerative Diseases, Department of Neurology, Georg-August University, University Medical Center Göttingen, Göttingen, Germany; Biomedical Engineering and Sciences Department, School of Mechanical and Manufacturing Engineering, National University of Sciences and Technology, Islamabad, Pakistan
| | - Aneeqa Noor
- Clinical Dementia Center and German Center for Neurodegenerative Diseases, Department of Neurology, Georg-August University, University Medical Center Göttingen, Göttingen, Germany
| | - Inga Zerr
- Clinical Dementia Center and German Center for Neurodegenerative Diseases, Department of Neurology, Georg-August University, University Medical Center Göttingen, Göttingen, Germany.
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Exploring Anti-Prion Glyco-Based and Aromatic Scaffolds: A Chemical Strategy for the Quality of Life. Molecules 2017; 22:molecules22060864. [PMID: 28538692 PMCID: PMC6152669 DOI: 10.3390/molecules22060864] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Revised: 05/16/2017] [Accepted: 05/17/2017] [Indexed: 01/08/2023] Open
Abstract
Prion diseases are fatal neurodegenerative disorders caused by protein misfolding and aggregation, affecting the brain progressively and consequently the quality of life. Alzheimer’s is also a protein misfolding disease, causing dementia in over 40 million people worldwide. There are no therapeutics able to cure these diseases. Cellular prion protein is a high-affinity binding partner of amyloid β (Aβ) oligomers, the most toxic species in Alzheimer’s pathology. These findings motivate the development of new chemicals for a better understanding of the events involved. Disease control is far from being reached by the presently known therapeutics. In this review we describe the synthesis and mode of action of molecular entities with intervention in prion diseases’ biological processes and, if known, their role in Alzheimer’s. A diversity of structures is covered, based on glycans, steroids and terpenes, heterocycles, polyphenols, most of them embodying aromatics and a structural complexity. These molecules may be regarded as chemical tools to foster the understanding of the complex mechanisms involved, and to encourage the scientific community towards further developments for the cure of these devastating diseases.
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Giles K, Olson SH, Prusiner SB. Developing Therapeutics for PrP Prion Diseases. Cold Spring Harb Perspect Med 2017; 7:cshperspect.a023747. [PMID: 28096242 DOI: 10.1101/cshperspect.a023747] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The prototypical PrP prion diseases are invariably fatal, and the search for agents to treat them spans more than 30 years, with limited success. However, in the last few years, the application of high-throughput screening, medicinal chemistry, and pharmacokinetic optimization has led to important advances. The PrP prion inoculation paradigm provides a robust assay for testing therapeutic efficacy, and a dozen compounds have been reported that lead to meaningful extension in survival of prion-infected mice. Here, we review the history and recent progress in the field, focusing on studies validated in animal models. Based on screens in cells infected with mouse-passaged PrP prions, orally available compounds were generated that double or even triple the survival of mice infected with the same prion strain. Unfortunately, no compounds have yet shown efficacy against human prions. Nevertheless, the speed of the recent advances brings hope that an effective therapeutic can be developed. A successful treatment for any neurodegenerative disease would be a major achievement, and the growing understanding that the more common neurodegenerative diseases, including Alzheimer's and Parkinson's, progress by an analogous prion mechanism serves to highlight the importance of antiprion therapeutics.
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Affiliation(s)
- Kurt Giles
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143.,Department of Neurology, University of California, San Francisco, San Francisco, California 94143
| | - Steven H Olson
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143.,Department of Neurology, University of California, San Francisco, San Francisco, California 94143
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, California 94143.,Department of Neurology, University of California, San Francisco, San Francisco, California 94143.,Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California 94143
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Giles K, Berry DB, Condello C, Dugger BN, Li Z, Oehler A, Bhardwaj S, Elepano M, Guan S, Silber BM, Olson SH, Prusiner SB. Optimization of Aryl Amides that Extend Survival in Prion-Infected Mice. J Pharmacol Exp Ther 2016; 358:537-47. [PMID: 27317802 DOI: 10.1124/jpet.116.235556] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2016] [Accepted: 06/16/2016] [Indexed: 11/22/2022] Open
Abstract
Developing therapeutics for neurodegenerative diseases (NDs) prevalent in the aging population remains a daunting challenge. With the growing understanding that many NDs progress by conformational self-templating of specific proteins, the prototypical prion diseases offer a platform for ND drug discovery. We evaluated high-throughput screening hits with the aryl amide scaffold and explored the structure-activity relationships around three series differing in their N-aryl core: benzoxazole, benzothiazole, and cyano. Potent anti-prion compounds were advanced to pharmacokinetic studies, and the resulting brain-penetrant leads from each series, together with a related N-aryl piperazine lead, were escalated to long-term dosing and efficacy studies. Compounds from each of the four series doubled the survival of mice infected with a mouse-passaged prion strain. Treatment with aryl amides altered prion strain properties, as evidenced by the distinct patterns of neuropathological deposition of prion protein and associated astrocytic gliosis in the brain; however, none of the aryl amide compounds resulted in drug-resistant prion strains, in contrast to previous studies on compounds with the 2-aminothiazole (2-AMT) scaffold. As seen with 2-AMTs and other effective anti-prion compounds reported to date, the novel aryl amides reported here were ineffective in prolonging the survival of transgenic mice infected with human prions. Most encouraging is our discovery that aryl amides show that the development of drug resistance is not an inevitable consequence of efficacious anti-prion therapeutics.
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Affiliation(s)
- Kurt Giles
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - David B Berry
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Carlo Condello
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Brittany N Dugger
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Zhe Li
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Abby Oehler
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Sumita Bhardwaj
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Manuel Elepano
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Shenheng Guan
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - B Michael Silber
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Steven H Olson
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases (K.G., D.B.B., C.C., B.N.D., Z.L., A.O., S.B., M.E., S.G., B.M.S., S.H.O., S.B.P.) and Departments of Neurology (K.G., C.C., B.N.D., Z.L., B.M.S., S.H.O., S.B.P.), Pharmaceutical Chemistry (S.G.), Bioengineering and Therapeutic Sciences (B.M.S.), and Biochemistry and Biophysics (S.B.P.), University of California, San Francisco, California
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Figueiredo CP, Ferreira NC, Passos GF, Costa RD, Neves FS, Machado CSC, Mascarello A, Chiaradia-Delatorre LD, Neuenfeldt PD, Nunes RJ, Cordeiro Y. Toxicological Evaluation of Anti-Scrapie Trimethoxychalcones and Oxadiazoles. AN ACAD BRAS CIENC 2015; 87:1421-34. [PMID: 26247149 DOI: 10.1590/0001-3765201520140712] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
An altered form of the cellular prion protein, the PrPScor PrPRes, is implicated in the occurrence of the still untreatable transmissible spongiform encephalopathies. We have previously synthesized and characterized aromatic compounds that inhibit protease-resistant prion protein (PrPRes) accumulation in scrapie-infected cells. These compounds belong to different chemical classes, including acylhydrazones, chalcones and oxadiazoles. Some of the active compounds were non-toxic to neuroblastoma cells in culture and seem to possess drugable properties, since they are in agreement with the Lipinski´s rule of 5 and present desirable pharmacokinetic profiles as predicted in silico. Before the evaluation of the in vivo efficacy of the aromatic compounds in scrapie-infected mice, safety assessment in healthy mice is needed. Here we used Swiss mice to evaluate the acute toxicity profile of the six most promising anti-prionic compounds, the 2,4,5-trimethoxychalcones (J1, J8, J20 and J35) and the 1,3,4-oxadiazoles (Y13 and Y17). One single oral administration (300 mg/kg) of J1, J8, J20, J35, Y13 and Y17 or repeated intraperitoneal administration (10 mg/kg, 3 times a week, for 4 weeks) of J1, J8 and J35, did not elicit toxicity in mice. We strongly believe that the investigated trimethoxychalcones and oxadiazoles are interesting compounds to be further analyzed in vivo against prion diseases.
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Affiliation(s)
- Claudia P Figueiredo
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Natalia C Ferreira
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Giselle F Passos
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Robson da Costa
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Fernanda S Neves
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Clarice S C Machado
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
| | - Alessandra Mascarello
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, SC, BR
| | | | - Patrícia D Neuenfeldt
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, SC, BR
| | - Ricardo J Nunes
- Departamento de Química, Universidade Federal de Santa Catarina, Florianópolis, SC, BR
| | - Yraima Cordeiro
- Faculdade de Farmácia, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, BR
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Silber BM, Gever JR, Rao S, Li Z, Renslo AR, Widjaja K, Wong C, Giles K, Freyman Y, Elepano M, Irwin JJ, Jacobson MP, Prusiner SB. Novel compounds lowering the cellular isoform of the human prion protein in cultured human cells. Bioorg Med Chem 2014; 22:1960-72. [PMID: 24530226 DOI: 10.1016/j.bmc.2014.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/23/2013] [Accepted: 01/01/2014] [Indexed: 11/20/2022]
Abstract
PURPOSE Previous studies showed that lowering PrP(C) concomitantly reduced PrP(Sc) in the brains of mice inoculated with prions. We aimed to develop assays that measure PrP(C) on the surface of human T98G glioblastoma and IMR32 neuroblastoma cells. Using these assays, we sought to identify chemical hits, confirmed hits, and scaffolds that potently lowered PrP(C) levels in human brains cells, without lethality, and that could achieve drug concentrations in the brain after oral or intraperitoneal dosing in mice. METHODS We utilized HTS ELISA assays to identify small molecules that lower PrP(C) levels by ≥30% on the cell surface of human glioblastoma (T98G) and neuroblastoma (IMR32) cells. RESULTS From 44,578 diverse chemical compounds tested, 138 hits were identified by single point confirmation (SPC) representing 7 chemical scaffolds in T98G cells, and 114 SPC hits representing 6 scaffolds found in IMR32 cells. When the confirmed SPC hits were combined with structurally related analogs, >300 compounds (representing 6 distinct chemical scaffolds) were tested for dose-response (EC₅₀) in both cell lines, only studies in T98G cells identified compounds that reduced PrP(C) without killing the cells. EC₅₀ values from 32 hits ranged from 65 nM to 4.1 μM. Twenty-eight were evaluated in vivo in pharmacokinetic studies after a single 10 mg/kg oral or intraperitoneal dose in mice. Our results showed brain concentrations as high as 16.2 μM, but only after intraperitoneal dosing. CONCLUSIONS Our studies identified leads for future studies to determine which compounds might lower PrP(C) levels in rodent brain, and provide the basis of a therapeutic for fatal disorders caused by PrP prions.
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Affiliation(s)
- B Michael Silber
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Neurology, University of California, San Francisco, United States; Department of Bioengineering and Therapeutic Sciences, University of California, San Francisco, United States
| | - Joel R Gever
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Neurology, University of California, San Francisco, United States
| | - Satish Rao
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Neurology, University of California, San Francisco, United States
| | - Zhe Li
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Neurology, University of California, San Francisco, United States
| | - Adam R Renslo
- Small Molecule Discovery Center, University of California, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, United States
| | - Kartika Widjaja
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States
| | - Casper Wong
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States
| | - Kurt Giles
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Neurology, University of California, San Francisco, United States
| | - Yevgeniy Freyman
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States
| | - Manuel Elepano
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States
| | - John J Irwin
- Department of Pharmaceutical Chemistry, University of California, San Francisco, United States
| | - Matthew P Jacobson
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Pharmaceutical Chemistry, University of California, San Francisco, United States
| | - Stanley B Prusiner
- Institute for Neurodegenerative Diseases, University of California, San Francisco, United States; Department of Neurology, University of California, San Francisco, United States.
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10
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Abstract
There is not a single pharmaceutical that halts or even slows any neurodegenerative disease. Mounting evidence shows that prions cause many neurodegenerative diseases, and arguably, scrapie and Creutzfeldt-Jakob disease prions represent the best therapeutic targets. We report here that the previously identified 2-aminothiazoles IND24 and IND81 doubled the survival times of scrapie-infected, wild-type mice. However, mice infected with Rocky Mountain Laboratory (RML) prions, a scrapie-derived strain, and treated with IND24 eventually exhibited neurological dysfunction and died. We serially passaged their brain homogenates in mice and cultured cells. We found that the prion strain isolated from IND24-treated mice, designated RML[IND24], emerged during a single passage in treated mice. Although RML prions infect both the N2a and CAD5 cell lines, RML[IND24] prions could only infect CAD5 cells. When passaged in CAD5 cells, the prions remained resistant to high concentrations of IND24. However, one passage of RML[IND24] prions in untreated mice restored susceptibility to IND24 in CAD5 cells. Although IND24 treatment extended the lives of mice propagating different prion strains, including RML, another scrapie-derived prion strain ME7, and chronic wasting disease, it was ineffective in slowing propagation of Creutzfeldt-Jakob disease prions in transgenic mice. Our studies demonstrate that prion strains can acquire resistance upon exposure to IND24 that is lost upon passage in mice in the absence of IND24. These data suggest that monotherapy can select for resistance, thus intermittent therapy with mixtures of antiprion compounds may be required to slow or stop neurodegeneration.
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