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Darvesh S, Banfield S, Dufour M, Forrestall KL, Maillet H, Reid GA, Sands D, Pottie IR. A method for the efficient evaluation of substrate-based cholinesterase imaging probes for Alzheimer's disease. J Enzyme Inhib Med Chem 2023; 38:2225797. [PMID: 38061987 PMCID: PMC10294744 DOI: 10.1080/14756366.2023.2225797] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2023] [Revised: 05/11/2023] [Accepted: 06/10/2023] [Indexed: 08/16/2023] Open
Abstract
Cholinesterase (ChE) enzymes have been identified as diagnostic markers for Alzheimer disease (AD). Substrate-based probes have been synthesised to detect ChEs but they have not detected changes in ChE distribution associated with AD pathology. Probes are typically screened using spectrophotometric methods with pure enzyme for specificity and kinetics. However, the biochemical properties of ChEs associated with AD pathology are altered. The present work was undertaken to determine whether the Karnovsky-Roots (KR) histochemical method could be used to evaluate probes at the site of pathology. Thirty thioesters and esters were synthesised and evaluated using enzyme kinetic and KR methods. Spectrophotometric methods demonstrated all thioesters were ChE substrates, yet only a few provided staining in the brain with the KR method. Esters were ChE substrates with interactions with brain ChEs. These results suggest that the KR method may provide an efficient means to screen compounds as probes for imaging AD-associated ChEs.
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Affiliation(s)
- Sultan Darvesh
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
- Department of Medicine (Geriatric Medicine & Neurology), Halifax, Nova Scotia, Canada
- Department of Chemistry and Physics, Mount St. Vincent University, Halifax, Nova Scotia, Canada
| | - Scott Banfield
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Maeve Dufour
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Katrina L. Forrestall
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Hillary Maillet
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - G. Andrew Reid
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Dane Sands
- Department of Medical Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ian R. Pottie
- Department of Chemistry and Physics, Mount St. Vincent University, Halifax, Nova Scotia, Canada
- Department of Chemistry, Saint Mary’s University, Halifax, Nova Scotia, Canada
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Dahn ML, Cruickshank BM, Jackson AJ, Dean C, Holloway RW, Hall SR, Coyle KM, Maillet H, Waisman DM, Goralski KB, Giacomantonio CA, Weaver ICG, Marcato P. Decitabine Response in Breast Cancer Requires Efficient Drug Processing and Is Not Limited by Multidrug Resistance. Mol Cancer Ther 2020; 19:1110-1122. [PMID: 32156786 DOI: 10.1158/1535-7163.mct-19-0745] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 01/30/2020] [Accepted: 03/05/2020] [Indexed: 11/16/2022]
Abstract
Dysregulation of DNA methylation is an established feature of breast cancers. DNA demethylating therapies like decitabine are proposed for the treatment of triple-negative breast cancers (TNBC) and indicators of response need to be identified. For this purpose, we characterized the effects of decitabine in a panel of 10 breast cancer cell lines and observed a range of sensitivity to decitabine that was not subtype specific. Knockdown of potential key effectors demonstrated the requirement of deoxycytidine kinase (DCK) for decitabine response in breast cancer cells. In treatment-naïve breast tumors, DCK was higher in TNBCs, and DCK levels were sustained or increased post chemotherapy treatment. This suggests that limited DCK levels will not be a barrier to response in patients with TNBC treated with decitabine as a second-line treatment or in a clinical trial. Methylome analysis revealed that genome-wide, region-specific, tumor suppressor gene-specific methylation, and decitabine-induced demethylation did not predict response to decitabine. Gene set enrichment analysis of transcriptome data demonstrated that decitabine induced genes within apoptosis, cell cycle, stress, and immune pathways. Induced genes included those characterized by the viral mimicry response; however, knockdown of key effectors of the pathway did not affect decitabine sensitivity suggesting that breast cancer growth suppression by decitabine is independent of viral mimicry. Finally, taxol-resistant breast cancer cells expressing high levels of multidrug resistance transporter ABCB1 remained sensitive to decitabine, suggesting that the drug could be used as second-line treatment for chemoresistant patients.
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Affiliation(s)
- Margaret L Dahn
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | | | - Ainsleigh J Jackson
- Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Cheryl Dean
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ryan W Holloway
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Steven R Hall
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Krysta M Coyle
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Hillary Maillet
- Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada
| | - David M Waisman
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Kerry B Goralski
- Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada.,College of Pharmacy, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Carman A Giacomantonio
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Surgery, Dalhousie University, Halifax, Nova Scotia, Canada
| | - Ian C G Weaver
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia, Canada.,Department of Psychiatry, Dalhousie University, Halifax, Nova Scotia, Canada.,Brain Repair Centre, Halifax, Nova Scotia, Canada
| | - Paola Marcato
- Department of Pathology, Dalhousie University, Halifax, Nova Scotia, Canada. .,Department of Microbiology and Immunology, Dalhousie University, Halifax, Nova Scotia, Canada
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