Reduced proinsecticide activation by cytochrome P450 confers coumaphos resistance in the major bee parasite Varroa destructor

Varroa destructor is one of the main problems in modern beekeeping. Highly selective acaricides with low toxicity to bees are used internationally to control this mite. One of the key acaricides is the organophosphorus (OP) proinsecticide coumaphos, that becomes toxic after enzymatic activation inside Varroa. We show here that mites from the island Andros (AN-CR) exhibit high levels of coumaphos resistance. Resistance is not mediated by decreased coumaphos uptake, target-site resistance, or increased detoxification. Reduced proinsecticide activation by a cytochrome P450 enzyme was the main resistance mechanism, a powerful and rarely encountered evolutionary solution to insecticide selection pressure. After treatment with sublethal doses of [14C] coumaphos, susceptible mite extracts had substantial amounts of coroxon, the activated metabolite of coumaphos, while resistant mites had only trace amounts. This indicates a suppression of the P450 (CYP)-mediated activation step in the AN-CR mites. Bioassays with coroxon to bypass the activation step showed that resistance was dramatically reduced. There are 26 CYPs present in the V. destructor genome. Transcriptome analysis revealed overexpression in resistant mites of CYP4DP24 and underexpression of CYP3012A6 and CYP4EP4. RNA interference of CYP4EP4 in the susceptible population, to mimic underexpression seen in the resistant mites, prevented coumaphos activation and decreased coumaphos toxicity.

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The role of cytochrome P450 enzyme genetic variants in cannabis hyperemesis syndrome—A case report

Basic & Clinical Pharmacology & Toxicology ◽

10.1111/bcpt.13581 ◽

2021 ◽

Author(s):

Maxim Kuzin ◽

Franziskos Xepapadakos ◽

Isabel Scharrer ◽

Marc Augsburger ◽

Chin‐Bin Eap ◽

...

Keyword(s):

Cytochrome P450 ◽

Case Report ◽

Genetic Variants ◽

Cytochrome P450 Enzyme ◽

P450 Enzyme ◽

Cannabis Hyperemesis Syndrome

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Inter-species comparisons of hepatic cytochrome P450 enzyme levels in male ruminants

Archives of Toxicology ◽

10.1007/s00204-003-0477-4 ◽

2003 ◽

Vol 77 (10) ◽

pp. 555-560 ◽

Cited By ~ 22

Author(s):

Miroslav Machala ◽

Pavel Soucek ◽

Jir� Neca ◽

Robert Ulrich ◽

Jir� Lamka ◽

...

Keyword(s):

Cytochrome P450 ◽

Cytochrome P450 Enzyme ◽

P450 Enzyme ◽

Species Comparisons ◽

Hepatic Cytochrome

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Glutathione S-Transferases and Cytochrome P450 Enzyme Expression in Patients with Intracranial Tumors: Preliminary Report of 55 Patients

Medical Principles and Practice ◽

10.1159/000494496 ◽

2018 ◽

Vol 28 (1) ◽

pp. 56-62

Author(s):

Cahit Kural ◽

Arzu Kaya Kocdogan ◽

Gulcin Güler Şimşek ◽

Serpil Oğuztüzün ◽

Pınar Kaygın ◽

...

Keyword(s):

Cytochrome P450 ◽

Brain Tissue ◽

Pituitary Adenomas ◽

Normal Brain ◽

Cytochrome P450 Enzyme ◽

Intracranial Tumors ◽

Glutathione S Transferase ◽

Normal Brain Tissue ◽

Tissue Samples ◽

P450 Enzyme

Objective: Intracranial tumors are one of the most frightening and difficult-to-treat tumor types. In addition to surgery, protocols such as chemotherapy and radiotherapy also take place in the treatment. Glutathione S-transferase (GST) and cytochrome P450 (CYP) enzymes are prominent drug-metabolizing enzymes in the human body. The aim of this study is to show the expression of GSTP1, GSTM1, CYP1A1, and CYP1B1 in different types of brain tumors and compare our results with those in the literature. Subjects and Methods: The expression of GSTP1, GSTM1, CYP1A1, and CYP1B1 was analyzed using immunostaining in 55 patients with intracranial tumors in 2016–2017. For GST and CYP expression in normal brain tissue, samples of a portion of surrounding normal brain tissue as well as a matched far neighbor of tumor tissue were used. The demographic features of the patients were documented and the expression results compared. Results: The mean age of the patients was 46.72 years; 29 patients were female and 26 were male. Fifty-seven specimens were obtained from 55 patients. Among them, meningioma was diagnosed in 12, metastases in 12, glioblastoma in 9, and pituitary adenoma in 5. The highest GSTP1, GSTM1, and CYP1A1 expressions were observed in pituitary adenomas. The lowest GSTP1 expression was detected in glioblastomas and the lowest CYP1B1 expression in pituitary adenomas. Conclusion: GSTP1 and CYP expression is increased in intracranial tumors. These results should be confirmed with a larger series and different enzyme subtypes.

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Drug Interactions of Macrolides: Emphasis on Dirithromycin

Annals of Pharmacotherapy ◽

10.1177/106002809703100314 ◽

1997 ◽

Vol 31 (3) ◽

pp. 349-356 ◽

Cited By ~ 28

Author(s):

Vish S Watkins ◽

Ron E Polk ◽

Jennifer L Stotka

Keyword(s):

Cytochrome P450 ◽

Drug Interactions ◽

Ethinyl Estradiol ◽

Enzyme System ◽

Cytochrome P450 Enzyme ◽

Cytochrome P450 Enzymes ◽

Kidney Transplant Recipients ◽

P450 Enzyme ◽

Cytochrome P450 Enzyme System ◽

Clinically Significant

Objective To describe the drug interactions of dirithromycin, a new macrolide, and to compare them with those of other macrolides. Data Sources A literature search was performed using MEDLINE to identify articles published between January 1980 and July 1995 concerning the drug interactions of macrolides. Published abstracts were also examined. All studies using dirithromycin were performed under the sponsorship of Eli Lilly and Company. Data Synthesis Erythromycin, the first macrolide discovered, is metabolized by the cytochrome P450 enzyme system. By decreasing their metabolism, erythromycin can interact with other drugs metabolized by the cytochrome P450 enzymes. The lack of such interactions would be a desirable feature in a newer macrolide. We describe studies performed to detect any interactions of dirithromycin with cyclosporine, theophylline, terfenadine, warfarin, and ethinyl estradiol. The studies showed that dirithromycin, like azithromycin, is much less likely to cause the interactions detected with clarithromycin and erythromycin. A review of the literature showed differences among macrolides in their abilities to inhibit cytochrome P450 enzymes and, thus, to cause drug–drug interactions. Erythromycin and clarithromycin inhibit cytochrome P450 enzymes, and have been implicated in clinically significant interactions. Azithromycin and dirithromycin neither inhibit cytochrome P450 enzymes nor are implicated in clinically significant drug–drug interactions. Conclusions Dirithromycin, a new macrolide, does not inhibit the cytochrome P450 enzyme system. The concomitant use of dirithromycin with cyclosporine, theophylline, terfenadine, warfarin, or ethinyl estradiol was studied in pharmacokinetic and pharmacodynamic studies. In vitro, dirithromycin did not bind cytochrome P450. In healthy subjects, erythromycin increases the clearance of cyclosporine by 51%, whereas dirithromycin causes no significant changes in the pharmacokinetics of cyclosporine. In kidney transplant recipients, administration of dirithromycin was associated with a significant (p < 0.003) decrease of 17.4% in the clearance of cyclosporine. In patients taking low-dose estradiol, the administration of dirithromycin caused a significant (p < 0.03) increase of 9.9% in the clearance of ethinyl estradiol; escape ovulation did not occur. Unlike erythromycin and clarithromycin, dirithromycin had no significant effects on the pharmacokinetics of theophylline, terfenadine, or warfarin. The alterations typical of drug interactions that are based on inhibition of the cytochrome P450 system occurring with erythromycin and clarithromycin were not observed with dirithromycin.

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