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Noga M, Zakrzewski M, Wianowska D, Gnatowski M, Paprotny Ł, Jurowski K. Development of innovative methodology for determination of 6-thioguanine in whole blood erythrocytes by HPLC-PDA-based technique for medical diagnostics purposes. Sci Rep 2023; 13:14172. [PMID: 37644112 PMCID: PMC10465597 DOI: 10.1038/s41598-023-41426-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2023] [Accepted: 08/26/2023] [Indexed: 08/31/2023] Open
Abstract
6-Thioguanine is an immunosuppressive drug, an analogue of guanine, applied to treat acute leukemia and inflammatory bowel disease. Excessive use of 6-thioguanine during clinical treatment may cause side effects. Moreover, providing a dose too low will be ineffective. Therefore, there is a critical need for a rapid, selective and routine approach to quantifying 6-thioguanine in body fluids to support a clinical application. A fully validated HPLC method has been developed to determine 6-thioguanine in whole blood samples using 5-bromouracil as an internal standard. 6-Thioguanine nucleotides were released from erythrocytes by perchloric acid, and then hydrolysed at 100 °C to the parent thiopurine, 6-thioguanine. The following validation parameters of the method were determined: specificity/selectivity, linearity range (479-17,118 ng/mL, R > 0.992), limits of detection (150 ng/mL) and quantification (479 ng/mL), accuracy (- 5.6 < Bias < 14.7), repeatability (CV 1.30-3.24%), intermediate precision (CV 4.19-5.78%), extraction recovery (79.1-103.6%) and carryover. Furthermore, the stability of the drug in whole blood samples under various storage conditions was investigated. The suggested method is suitable for determining 6-thioguanine in whole blood erythrocyte samples for drug level monitoring, thus correct dosing.
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Affiliation(s)
- Maciej Noga
- Department of Regulatory and Forensic Toxicology, Institute of Medical Expertises, Ul. Aleksandrowska 67/93, 91-205, Lodz, Poland
| | - Marcin Zakrzewski
- ALAB Laboratories, Research and Development Centre, Ul. Ceramiczna 1, 20-150, Lublin, Poland
| | - Dorota Wianowska
- Department of Chromatographic Methods, Faculty of Chemistry, Maria Curie-Skłodowska University, Pl. Maria Curie-Skłodowska 3, 20-031, Lublin, Poland
| | - Maciej Gnatowski
- ALAB Laboratories, Research and Development Centre, Ul. Ceramiczna 1, 20-150, Lublin, Poland
| | - Łukasz Paprotny
- ALAB Laboratories, Research and Development Centre, Ul. Ceramiczna 1, 20-150, Lublin, Poland
| | - Kamil Jurowski
- Department of Regulatory and Forensic Toxicology, Institute of Medical Expertises, Ul. Aleksandrowska 67/93, 91-205, Lodz, Poland.
- Institute of Medical Studies, MedicalCollege, Rzeszów University, Al. mjrr. W. Kopisto 2a, 35-959, Rzeszow, Poland.
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Unal DN, Eksin E, Erdem A. Electrochemical Determination of 6-Thioguanine and Its Interaction with DNA Oligonucleotides Using Disposable Graphite Pencil Electrodes. ANAL LETT 2017. [DOI: 10.1080/00032719.2017.1338714] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Didem Nur Unal
- Faculty of Pharmacy, Analytical Chemistry Department, Ege University, Izmir, Turkey
| | - Ece Eksin
- Faculty of Pharmacy, Analytical Chemistry Department, Ege University, Izmir, Turkey
| | - Arzum Erdem
- Faculty of Pharmacy, Analytical Chemistry Department, Ege University, Izmir, Turkey
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Thiopurines induce oxidative stress in T-lymphocytes: a proteomic approach. Mediators Inflamm 2015; 2015:434825. [PMID: 25873760 PMCID: PMC4385670 DOI: 10.1155/2015/434825] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/06/2014] [Accepted: 09/09/2014] [Indexed: 01/24/2023] Open
Abstract
Thiopurines are extensively used immunosuppressants for the treatment of inflammatory bowel disease (IBD). The polymorphism of thiopurine S-methyltransferase (TPMT) influences thiopurine metabolism and therapy outcome. We used a TPMT knockdown (kd) model of human Jurkat T-lymphocytes cells to study the effects of treatment with 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) on proteome and phosphoproteome. We identified thirteen proteins with altered expression and nine proteins with altered phosphorylation signals. Three proteins (THIO, TXD17, and GSTM3) with putative functions in cellular oxidative stress responses were altered by 6-TG treatment and another protein PRDX3 was differentially phosphorylated in TPMT kd cells. Furthermore, reactive oxygen species (ROS) assay results were consistent with a significant induction of oxidative stress by both TPMT knockdown and thiopurine treatments. Immunoblot analyses showed treatment altered expression of key antioxidant enzymes (i.e., SOD2 and catalase) in both wt and kd groups, while SOD1 was downregulated by 6-TG treatment and TPMT knockdown. Collectively, increased oxidative stress might be a mechanism involved in thiopurine induced cytotoxicity and adverse effects (i.e., hepatotoxicity) and an antioxidant cotherapy might help to combat this. Results highlight the significance of oxidative stress in thiopurines' actions and could have important implications for the treatment of IBD patients.
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Karim H, Ghalali A, Lafolie P, Vitols S, Fotoohi AK. Differential role of thiopurine methyltransferase in the cytotoxic effects of 6-mercaptopurine and 6-thioguanine on human leukemia cells. Biochem Biophys Res Commun 2013; 437:280-6. [PMID: 23811272 DOI: 10.1016/j.bbrc.2013.06.067] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2013] [Accepted: 06/18/2013] [Indexed: 11/24/2022]
Abstract
The thiopurine antimetabolites, 6-mercaptopurine (6-MP) and 6-thioguanine (6-TG) are inactive pro-drugs that require intracellular metabolism for activation to cytotoxic metabolites. Thiopurine methyltransferase (TPMT) is one of the most important enzymes in this process metabolizing both 6-MP and 6-TG to different methylated metabolites including methylthioinosine monophosphate (meTIMP) and methylthioguanosine monophosphate (meTGMP), respectively, with different suggested pharmacological and cytotoxic properties. While meTIMP is a potent inhibitor of de novo purine synthesis (DNPS) and significantly contributes to the cytotoxic effects of 6-MP, meTGMP, does not add much to the effects of 6-TG, and the cytotoxicity of 6-TG seems to be more dependent on incorporation of thioguanine nucleotides (TGNs) into DNA rather than inhibition of DNPS. In order to investigate the role of TPMT in metabolism and thus, cytotoxic effects of 6-MP and 6-TG, we knocked down the expression of the gene encoding the TPMT enzyme using specifically designed small interference RNA (siRNA) in human MOLT4 leukemia cells. The knock-down was confirmed at RNA, protein, and enzyme function levels. Apoptosis was determined using annexin V and propidium iodide staining and FACS analysis. The results showed a 34% increase in sensitivity of MOLT4 cells to 1μM 6-TG after treatment with TPMT-targeting siRNA, as compared to cells transfected with non-targeting siRNA, while the sensitivity of the cells toward 6-MP was not affected significantly by down-regulation of the TPMT gene. This differential contribution of the enzyme TPMT to the cytotoxicity of the two thiopurines is probably due to its role in formation of the meTIMP, the cytotoxic methylated metabolite of 6-MP, while in case of 6-TG methylation by TPMT substantially deactivates the drug.
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Affiliation(s)
- Hazhar Karim
- Department of Medicine, Clinical Pharmacology Unit, Karolinska Institutet, SE-171 76 Stockholm, Sweden.
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