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Fadahunsi AI, Kumm C, Graham K, de León AAP, Guerrero F, Sparagano OAE, Finn RD. Biochemical characterisation of Cytochrome P450 oxidoreductase from the cattle tick, Rhipicephalus microplus, highlights potential new acaricide target. Ticks Tick Borne Dis 2023; 14:102148. [PMID: 36905815 DOI: 10.1016/j.ttbdis.2023.102148] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 08/09/2022] [Revised: 02/23/2023] [Accepted: 02/23/2023] [Indexed: 03/12/2023]
Abstract
Management of the cattle tick, Rhipicephalus microplus, presents a challenge because some populations of this cosmopolitan and economically important ectoparasite are resistant to multiple classes of acaricides. Cytochrome P450 oxidoreductase (CPR) is part of the cytochrome P450 (CYP450) monooxygenases that are involved in metabolic resistance by their ability to detoxify acaricides. Inhibiting CPR, the sole redox partner that transfers electrons to CYP450s, could overcome this type of metabolic resistance. This report represents the biochemical characterisation of a CPR from ticks. Recombinant CPR of R. microplus (RmCPR), minus its N-terminal transmembrane domain, was produced in a bacterial expression system and subjected to biochemical analyses. RmCPR displayed a characteristic dual flavin oxidoreductase spectrum. Incubation with nicotinamide adenine dinucleotide phosphate (NADPH) lead to an increase in absorbance between 500 and 600 nm with a corresponding appearance of a peak absorbance at 340-350 nm indicating functional transfer of electrons between NADPH and the bound flavin cofactors. Using the pseudoredox partner, kinetic parameters for both cytochrome c and NADPH binding were calculated as 26.6 ± 11.4 µM and 7.03 ± 1.8 µM, respectively. The turnover, Kcat, for RmCPR for cytochrome c was calculated as 0.08 s-1 which is significantly lower than the CPR homologues of other species. IC50 (Half maximal Inhibitory Concentration) values obtained for the adenosine analogues 2', 5' ADP, 2'- AMP, NADP+and the reductase inhibitor diphenyliodonium were: 140, 82.2, 24.5, and 75.3 µM, respectively. Biochemically, RmCPR resembles CPRs of hematophagous arthropods more so than mammalian CPRs. These findings highlight the potential of RmCPR as a target for the rational design of safer and potent acaricides against R. microplus.
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Affiliation(s)
- Adeyinka I Fadahunsi
- Department of Biological Sciences, Biotechnology Programme, Elizade University, Ondo State, Nigeria
| | - Christopher Kumm
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University Newcastle, Newcastle Upon Tyne NE1 8ST, UK
| | - Kirsty Graham
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University Newcastle, Newcastle Upon Tyne NE1 8ST, UK
| | - Adalberto A Pérez de León
- Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, U.S. Department of Agriculture, Agricultural Research Service, Kerrville, TX, USA
| | - Felix Guerrero
- Knipling-Bushland U.S. Livestock Insects Research Laboratory and Veterinary Pest Genomics Center, U.S. Department of Agriculture, Agricultural Research Service, Kerrville, TX, USA
| | - Oliver A E Sparagano
- Department of Public Health and Infectious Diseases, Jockey Club College of Veterinary Medicine and Life Sciences, City University of Hong Kong, Kowloon Tong, Hong Kong SAR, China
| | - Robert D Finn
- Department of Applied Sciences, Faculty of Health and Life Sciences, Northumbria University Newcastle, Newcastle Upon Tyne NE1 8ST, UK; Department of Biochemistry & Genetics, Faculty of Health & Life Sciences, St George's International School of Medicine, Northumbria University, Newcastle Upon Tyne NE1 8ST, UK.
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Chen S, Wu D, Liu Q, Jin F, Yao F, Fang Y. POR overexpression induces tamoxifen-resistance in breast cancer through the STAT1/c-Myc pathway. Mol Carcinog 2023; 62:249-260. [PMID: 36321415 DOI: 10.1002/mc.23481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [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: 08/16/2022] [Revised: 10/09/2022] [Accepted: 10/12/2022] [Indexed: 01/20/2023]
Abstract
Breast cancer is the most common cancer in women worldwide. Although tamoxifen (TAM), a selective estrogen receptor (ER) modulator, is widely used to treat ER-positive breast cancers, resistance to TAM remains a major clinical problem. NADPH-dependent cytochrome P450 reductase (POR) is known to participate in drug metabolism and steroid metabolism. Recent studies showed that high POR expression was correlated with poor outcomes in triple-negative breast cancer (TNBC), and POR might be a prognostic biomarker in TNBC. However, the role of POR in TAM resistance is still elusive. In this study, we found that high POR expression was associated with poor prognosis of ER-positive and TAM-treated breast cancer patients. In addition, COX analysis showed that POR expression was an independent prognostic biomarker for ER-positive as well as TAM-treated breast cancer patients. Furthermore, our results suggested that POR overexpression promoted TAM resistance by activating the STAT1/c-Myc pathway in ER-positive breast cancer cells. Immunohistochemical analysis showed that high POR/STAT1 expression was correlated with poor prognosis in TAM-treated breast cancer patients. Notably, combined treatment with TAM and a specific STAT1 inhibitor Fludarabine was more effective for inhibiting TAM-resistant breast cancer cells. Altogether, our findings suggested that POR overexpression induced TAM resistance through STAT1/c-Myc pathway and might serve as an independent prognostic biomarker in TAM-treated breast cancer patients. Combining TAM and STAT1 inhibitors might be an effective strategy for treating POR-induced TAM-resistant breast cancer.
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Affiliation(s)
- Si Chen
- Department of Microbial and Biochemical Pharmacy, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China
| | - Dingjie Wu
- Department of Microbial and Biochemical Pharmacy, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China
| | - Qiannan Liu
- Department of Microbial and Biochemical Pharmacy, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China
| | - Feng Jin
- Department of Breast Surgery and Surgical Oncology, Research Unit of General Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Fan Yao
- Department of Breast Surgery and Surgical Oncology, Research Unit of General Surgery, The First Affiliated Hospital of China Medical University, Shenyang, Liaoning Province, China
| | - Yue Fang
- Department of Microbial and Biochemical Pharmacy, School of Pharmacy, China Medical University, Shenyang, Liaoning Province, China
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Macheroux P. Current topics in flavins and flavoproteins (Proceedings of the 20th nternational symposium on flavins and flavoproteins). Arch Biochem Biophys 2021; 707:108908. [PMID: 33984324 DOI: 10.1016/j.abb.2021.108908] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
- Peter Macheroux
- Graz University of Technology, Petersgasse 12, 8010, Graz, Austria.
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