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- Apellániz-Ruiz, Maria, et al.
(författare)
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Targeted sequencing reveals low-frequency variants in EPHA genes as markers of paclitaxel-induced peripheral neuropathy.
- 2017
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Ingår i: Clinical Cancer Research. - : American Association of Cancer Research. - 1078-0432 .- 1557-3265. ; 23:5, s. 1227-1235
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: Neuropathy is the dose limiting toxicity of paclitaxel and a major cause for decreased quality of life. Genetic factors have been shown to contribute to paclitaxel neuropathy susceptibility; however, the major causes for inter-individual differences remain unexplained. In this study we identified genetic markers associated with paclitaxel-induced neuropathy through massive sequencing of candidate genes.EXPERIMENTAL DESIGN: We sequenced the coding region of 4 EPHA genes, 5 genes involved in paclitaxel pharmacokinetics and 30 Charcot-Marie-Tooth genes, in 228 cancer patients with no/low neuropathy or high grade neuropathy during paclitaxel treatment. An independent validation series included 202 paclitaxel-treated patients. Variation-/ gene-based analyses were used to compare variant frequencies among neuropathy groups and Cox regression models were used to analyze neuropathy evolution along treatment.RESULTS: Gene-based analysis identified EPHA6 as the gene most significantly associated with paclitaxel-induced neuropathy. Low frequency non-synonymous variants in EPHA6 were present exclusively in patients with high neuropathy and all affected the ligand binding domain. Accumulated dose analysis in the discovery series showed a significantly higher neuropathy risk for EPHA5/6/8 low-frequency non-synonymous variant carriers (HR=14.60, 95%CI=2.33-91.62, P=0.0042) and an independent cohort confirmed an increased neuropathy risk (HR=2.07, 95%CI=1.14-3.77, P=0.017). Combining the series gave an estimated 2.50-fold higher risk of neuropathy (95%CI=1.46-4.31; P=9.1x10(-4)).CONCLUSION: This first study sequencing EPHA genes revealed that low frequency variants in EPHA6, EPHA5 and EPHA8 contribute to the susceptibility to paclitaxel-induced neuropathy. Furthermore, EPHAs neuronal injury repair function suggests that these genes might constitute important neuropathy markers for many neurotoxic drugs.
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| 4. |
- Fuhrmann, A., et al.
(författare)
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Molecular mechanisms underlying the effects of cyclosporin A and sirolimus on glucose and lipid metabolism in liver, skeletal muscle and adipose tissue in an in vivo rat model
- 2014
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Ingår i: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952 .- 1356-1839. ; 88:2, s. 216-228
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Tidskriftsartikel (refereegranskat)abstract
- Cyclosporin A (CsA) and sirolimus (SRL) are immunosuppressive agents (IAs) associated with dyslipidemia, insulin resistance and new onset diabetes after transplantation (NODAT). However, the molecular mechanisms involved are not fully understood. We investigated the effects of six-week treatment of either CsA or SRL on glucose and lipid metabolism in Wistar rats. The results show that, compared with vehicle-treated rats, SRL-treated rats were significantly lighter starting at week 5. CsA or SRL caused glucose intolerance, increased storage of lipids in the liver and skeletal muscle, and decreased the insulin-stimulated glucose uptake in isolated adipocytes. Furthermore, these agents significantly decreased genes involved in insulin action and glucose uptake, such as, IRS-1, Glut4 and Glut1, and increased genes and/or proteins involved in hepatic lipogenesis and gluconeogenesis, while decreasing them in adipose tissue. After either treatment PGC1 alpha gene expression was down regulated in skeletal muscle, an important player in fatty acid oxidation. Moreover, there was an increase in IL-6 gene expression in adipose tissue in the SRL-treated rats, suggesting stimulation of lipolysis. The results of the present study suggest that CsA and SRL lead to metabolic alterations in liver, muscle and adipose tissue, which may contribute to the development of dyslipidemia and insulin resistance associated with immunosuppressive therapy. (C) 2014 Elsevier Inc. All rights reserved.
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| 5. |
- Lopes, P. C., et al.
(författare)
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Cyclosporine A enhances gluconeogenesis while sirolimus impairs insulin signaling in peripheral tissues after 3 weeks of treatment
- 2014
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Ingår i: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952 .- 1356-1839. ; 91:1, s. 61-73
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Tidskriftsartikel (refereegranskat)abstract
- Cyclosporine A (CsA) and sirolimus (SRL) are immunosuppressive agents (IA) associated with new-onset diabetes after transplantation (NODAT). This study aims to evaluate the effects of 3-weeks of treatment with either CsA (5 mg/kg BW/day) or SRL (1 mg/kg BW/day) on insulin signaling and expression of markers involved in glucose metabolism in insulin-sensitive tissues, in Wistar rats. Although no differences were observed in fasting glucose, insulin or C-peptide levels, both treated groups displayed an impaired glucose excursion during both glucose and insulin tolerance tests. These results suggest glucose intolerance and insulin resistance. An increase in glucose-6-phosphatase protein levels (68%, p<0.05) and in protein-tyrosine phosphatase 1B (163%,p<0.05), a negative regulator of insulin was observed in the CsA-treated group in the liver, indicating enhanced gluconeogenesis and increased insulin resistance. On the other hand, glucokinase protein levels were decreased in the SRL group (35%, p < 0.05) compared to vehicle, suggesting a decrease in glucose disposal. SRI treatment also reduced peroxisome proliferator-activated receptor gamma coactivator 1 alpha protein expression in muscle (similar to 50%, p<0.05), while no further protein alterations were observed in muscle and perirenal adipose tissue nor with the CsA treatment. Moreover, the phosphorylation of key proteins of the insulin signaling cascade was suppressed in the SRL group, but was unchanged by the CsA treatment. Taken together, these data suggest that CsA treatment enhances gluconeogenic factors in liver, while SRL treatment impairs insulin signaling in peripheral tissues, which can contribute to the development of insulin resistance and NODAT associated with immunosuppressive therapy.
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| 6. |
- Lopes, Patricia C., et al.
(författare)
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Short and long term in vivo effects of Cyclosporine A and Sirolimus on genes and proteins involved in lipid metabolism in Wistar rats
- 2014
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Ingår i: Metabolism. - : Elsevier BV. - 0026-0495 .- 1532-8600. ; 63:5, s. 702-715
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Cyclosporine A (CsA) and sirolimus (SRL) are immunosuppressive agents (IA) associated with new onset diabetes after transplantation and dyslipidemia. We aim to evaluate the molecular effects of CsA (5 mg/kg/day) and SRL (1 mg/kg/day) treatment for 3 and 9 weeks on lipid metabolism, in Wistar rats. Materials/Methods. Lipolysis was evaluated in isolated adipocytes, while triglycerides (TG) and non-esterified fatty acid (NEFA) were measured in serum. Gene and protein expression involved in lipid metabolism was assessed in adipose tissue and liver. Results. CsA and SRL treatments of rats for 3 and 9 weeks increased isoproterenol-stimulated lipolysis by 5-9 fold and 4-6 fold in isolated adipocytes, respectively. While CsA increased adipocyte weight and diameter, as well as NEFA and TG levels in circulation after 9 weeks, SRL treatment caused ectopic deposition of TG in the liver after 3 weeks. Moreover, ACC1 and FAS protein expression was increased after 3 weeks (>100%, p < 0.01), while HSL was increased after 9 weeks of CsA treatment. On the other hand, SRL decreased the expression of lipogenic genes, including ACC1 (50%, p < 0.05), lipin1 (25%, p < 0.05), PPAR-gamma (42%, p < 0.05) and SCD1 (80%, p < 0.001) in adipose tissue, after 3 weeks of treatment. Conclusion. The effects of both IAs on expression of lipolytic and lipogenic genes suggest that these agents influence lipid metabolism, thus contributing to the dyslipidemia observed during immunosuppressive therapy.
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| 7. |
- Lopes, P., et al.
(författare)
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Effects of Cyclosporine and Sirolimus on Insulin-Stimulated Glucose Transport and Glucose Tolerance in a Rat Model
- 2013
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Ingår i: Transplantation Proceedings. - : Elsevier BV. - 0041-1345 .- 1873-2623. ; 45:3, s. 1142-1148
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Tidskriftsartikel (refereegranskat)abstract
- Cyclosporine (CsA) and sirolimus (SRL) have been associated with undesirable side effects, including posttransplantation diabetes and hyperlipidemia, but the molecular mechanisms underlying these effects remain to be elucidated. Animal studies focusing on clinically relevant doses are advised. This study sought to compare the metabolic effects on isolated rat adipocytes treated with either CsA or SRL ex vivo and after long-term in vivo treatment in Wistar rats. We assessed the ex vivo effects of CsA (0.5–30 μmol/L) and SRL (1–250 μmol/L) on insulin-stimulated 14C-glucose uptake in epididymal adipocytes (n = 6–9). In parallel, rats (n = 12) were treated with either vehicle, CsA (5 mg/kg/d) or SRL (1 mg/kg/d) for either 3 or 9 weeks. At the end of the treatment, glucose tolerance test (GTT) and insulin-stimulated 14C-glucose uptake as well as biochemical parameters were analyzed. A significant reduction in the insulin-stimulated glucose uptake over basal was observed among isolated adipocytes, whether exposed ex vivo or in vivo to CsA or SRL treatment. Furthermore, the SRL group showed significantly lighter fat pads and smaller adipocytes at 3 weeks with a smaller gain in body weight throughout the study compared with either the vehicle or CsA cohorts. Glucose intolerance was observed after a GTT, at the end of the treatment with either drug. Additionally, at 9 weeks serum triglycerides were increased by CsA compared with vehicle or SRL treatment. Interestingly, although SRL-treated animals presented higher fed and fasted insulin levels compared with either group, suggesting insulin resistance, the CsA group presented lower fed and fasted insulin values, suggesting a defect in insulin secretion at 9 weeks. These results suggested that either ex vivo treatment of fat cells or in vivo treatment of rats with CsA or SRL impaired insulin-stimulated glucose uptake by adipocytes. Both drugs caused glucose intolerance, which altogether could be responsible for the development of posttransplantation diabetes. The introduction of calcineurin inhibitors, like cyclosporine (CsA), has been important to save lives and improve the safety of organ transplantations. However, the use of these drugs is followed by the emergence of a number of side effects that impact the patient's quality of life. One of the most important is new-onset diabetes mellitus after transplantation (NODAT),1, 2 and 3 which is usually associated with an increased risk of cardiovascular diseases and consequently decreased patient survival.3, 4 and 5 CsA, a peptide of fungal origin, CsA, forms a complex with cyclophilins, which then inhibits calcineurin, preventing the movement of transcription factors into the nucleus, thus blocking interleukin (IL)-2 production and, consequently, proliferation and differentiation of T cells.6 and 7 Studies on purified islets and insulin-producing beta cells have proposed various diabetogenic actions of CsA. Therefore, CsA decreases insulin content of the beta cell, reversibly inhibiting insulin gene transcription and ultimately insulin secretion,8 although the mechanisms that lead to these effects are not well understood.
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