Modulation et ciblage du facteur de croissance de l'endothélium vasculaire (VEGF) dans le carcinome à cellules rénales post-transplantation

In this work, we investigated the impact of cyclosporine A (CsA) exposure on angiogenic signalling in renal cell carcinoma (RCC), the second mostly observed cancer in renal transplanted patients. We examined in vitro the effect of CsA exposure on the Unfolded Protein Response (UPR) and the regulation of secreted proteins with a focus on VEGF (Vascular Endothelial Growth Factor) regulation. We confirm the effect of CsA on proteostasis and we show that the activation of UPR by CsA, leading to an increased VEGF hypoxic expression, could contribute to the aggressiveness of tumours. We propose to investigate a list of candidate UPR biomarkers in patients who have developed a post-transplant RCC in order to confirm the alteration of proteostasis and the UPR activation in this context. In the field of personalized medicine, other approaches such as pharmacogenetics are now used in medical practice. In this context, we evaluated the VEGF genotyping in a cohort of renal transplanted patients. We show that VEGF 936 C>T is significantly associated with the risk of developing a post-transplant RCC. Although it is evident that additional studies need to be conducted, our results indicate that VEGF 936 C>T genotypes might be useful to classify patients according to their post-transplant RCC risk in order to improve immunosuppressive drugs managementAu cours de ce travail, nous nous sommes intéressés à l'impact de l'exposition à la ciclosporine A (CsA) sur la signalisation angiogénique dans le carcinome à cellules rénales (renal cell carcinoma – RCC) qui représente la deuxième cause de cancer chez les patients transplantés rénaux. Nous avons examiné in vitro l'impact de l'exposition à la CsA sur la réponse UPR (Unfolded Protein Response) et la régulation des protéines sécrétées en portant un intérêt particulier à la régulation du VEGF (Vascular Endothelial Growth factor). Nous confirmons l'effet de la CsA sur la protéostase et montrons que l'activation de l'UPR par la CsA, conduisant à une augmentation de la production de VEGF en hypoxie, pourrait participer à l'agressivité des tumeurs. Nous proposons de rechercher certains biomarqueurs de l'UPR chez les patients ayant développé un RCC post-transplantation afin d'examiner de façon plus approfondie l'altération de la protéostase et la régulation de l'UPR dans ce contexte. Dans le domaine de la médecine personnalisée, d'autres approches comme la pharmacogénétique sont désormais utilisées dans la pratique médicale. Dans ce contexte, nous avons évalué l'intérêt du génotypage du VEGF dans une cohorte de patients transplantés rénaux. Nous montrons que le polymorphisme VEGF 936 C>T est associé de façon significative au risque de développer un RCC post-transplantation. Même s'il est évident que des études supplémentaires doivent être menées, nos résultats indiquent que le génotypage de VEGF 936 C>T pourrait être envisagé pour améliorer la gestion des traitements immunosuppresseurs chez les patients identifiés comme étant à risque de développer un RCC post-transplantatio

Modulation and targeting of the vascular endothelial growth factor (VEGF) in post-transplant renal cell carcinoma

Au cours de ce travail, nous nous sommes intéressés à l'impact de l'exposition à la ciclosporine A (CsA) sur la signalisation angiogénique dans le carcinome à cellules rénales (renal cell carcinoma – RCC) qui représente la deuxième cause de cancer chez les patients transplantés rénaux. Nous avons examiné in vitro l'impact de l'exposition à la CsA sur la réponse UPR (Unfolded Protein Response) et la régulation des protéines sécrétées en portant un intérêt particulier à la régulation du VEGF (Vascular Endothelial Growth factor). Nous confirmons l'effet de la CsA sur la protéostase et montrons que l'activation de l'UPR par la CsA, conduisant à une augmentation de la production de VEGF en hypoxie, pourrait participer à l'agressivité des tumeurs. Nous proposons de rechercher certains biomarqueurs de l'UPR chez les patients ayant développé un RCC post-transplantation afin d'examiner de façon plus approfondie l'altération de la protéostase et la régulation de l'UPR dans ce contexte. Dans le domaine de la médecine personnalisée, d'autres approches comme la pharmacogénétique sont désormais utilisées dans la pratique médicale. Dans ce contexte, nous avons évalué l'intérêt du génotypage du VEGF dans une cohorte de patients transplantés rénaux. Nous montrons que le polymorphisme VEGF 936 C>T est associé de façon significative au risque de développer un RCC post-transplantation. Même s'il est évident que des études supplémentaires doivent être menées, nos résultats indiquent que le génotypage de VEGF 936 C>T pourrait être envisagé pour améliorer la gestion des traitements immunosuppresseurs chez les patients identifiés comme étant à risque de développer un RCC post-transplantationIn this work, we investigated the impact of cyclosporine A (CsA) exposure on angiogenic signalling in renal cell carcinoma (RCC), the second mostly observed cancer in renal transplanted patients. We examined in vitro the effect of CsA exposure on the Unfolded Protein Response (UPR) and the regulation of secreted proteins with a focus on VEGF (Vascular Endothelial Growth Factor) regulation. We confirm the effect of CsA on proteostasis and we show that the activation of UPR by CsA, leading to an increased VEGF hypoxic expression, could contribute to the aggressiveness of tumours. We propose to investigate a list of candidate UPR biomarkers in patients who have developed a post-transplant RCC in order to confirm the alteration of proteostasis and the UPR activation in this context. In the field of personalized medicine, other approaches such as pharmacogenetics are now used in medical practice. In this context, we evaluated the VEGF genotyping in a cohort of renal transplanted patients. We show that VEGF 936 C>T is significantly associated with the risk of developing a post-transplant RCC. Although it is evident that additional studies need to be conducted, our results indicate that VEGF 936 C>T genotypes might be useful to classify patients according to their post-transplant RCC risk in order to improve immunosuppressive drugs managemen

Mise en place et validation d'une méthode de dosage plasmatique de la ribavirine par le LC-MS/MS (application chez les patients traités pour une épatite C chronique)

La ribavirine est une molécule antivirale indiquée dans le traitement de l hépatite C virale en association avec l interféron pégylé. Il est désormais démontré que le suivi thérapeutique pharmacologique de la ribavirine, assuré par la mesure des concentrations plasmatiques de ribavirine à l équilibre, est justifié. En effet, la pharmacocinétique de la ribavirine présente une forte variabilité inter-individuelle, les posologies ne permettant pas de présumer de l efficacité du traitement. De plus, une corrélation entre les concentrations sanguines et l efficacité clinique ou la toxicité a bien été établie. Une technique de dosage plasmatique de la ribavirine par LC-MS/MS a donc été développée au laboratoire de Pharmacologie-Toxicologie du CHU d Amiens afin de permettre une adaptation individualisée. Ainsi, des concentrations sanguines de ribavirine, garantissant une efficacité optimale du traitement tout en minimisant la survenue d anémie hémolytique (effet secondaire majeur lié à la prise de ribavirine), pourront être maintenues. La technique mise en place a ensuite été validée analytiquement à la fois pour garantir la fiabilité des résultats rendus et s inscrire dans une démarche de qualité conformément aux critères de la norme ISO-15189. Au-delà de l activité clinique, ce dosage peut-être mis à profit dans le cadre d études locales fondamentales ou cliniques. En effet, une étude, chez des patients infectés par le virus de l hépatite C et traités par bithérapie, a été mise en place. Le but de cette étude a été d évaluer l impact des concentrations sanguines de ribavirine en fin de traitement sur la rechute.Ribavirin is an antiviral molecule indicated for the treatment of hepatitis C virus in combination with pegylated interferon. It is now demonstrated that therapeutic drug monitoring of ribavirin, assured by measuring ribavirin plasma concentrations in equilibrium, is justified. Indeed, the pharmacokinetics of ribavirin has a high inter-individual variability. In addition, a correlation between blood levels and clinical efficacy or toxicity has been established. A LC-MS/MS method has been developed in the laboratory of Pharmacology and Toxicology (Amiens University Hospital) for the determination of ribavirin in plasma to allow individual adaptation. Thus, blood concentrations of ribavirin can be maintained in order to ensure optimum efficiency of treatment and to minimize the occurrence of hemolytic anemia (a major side effect associated with ribavirin). After developpement, this method was then validated analytically both to ensure the reliability of results and to enroll in a quality approach according to the ISO 15189 quality standard. This assay may also be used in local clinical or fundamental studies. Indeed, we etablished a study in patients infected with chronic hepatitis C and treated with ribavirin and pegylated interferon. The purpose of this study was to evaluate the-end-of treatment ribavirin concentrations to predict HCV relapse.AMIENS-BU Santé (800212102) / SudocSudocFranceF

The Prescription of Drugs That Inhibit Organic Anion Transporters 1 or 3 Is Associated with the Plasma Accumulation of Uremic Toxins in Kidney Transplant Recipients

The renal elimination of uremic toxins (UTs) can be potentially altered by drugs that inhibit organic anion transporters 1/3 (OAT1/OAT3). The objective of the present study was to determine whether the prescription of at least one OAT1/OAT3 inhibitor was associated with the plasma accumulation of certain UTs in kidney transplant recipients. We included 403 kidney transplant recipients. For each patient, we recorded all prescription drugs known to inhibit OAT1/OAT3. Plasma levels of four UTs (trimethylamine N-oxide (TMAO), indole acetic acid (IAA), para-cresylsulfate (pCS), and indoxylsulfate (IxS) were assayed using liquid chromatography-tandem mass spectrometry. Plasma UT levels were significantly higher among patients prescribed at least one OAT inhibitor (n = 311) than among patients not prescribed any OAT inhibitors (n = 92). Multivariate analysis revealed that after adjustment for age, estimated glomerular filtration rate (eGFR), plasma level of albumin and time since transplantation, prescription of an OAT1/OAT3 inhibitor was independently associated with the plasma accumulation of pCS (adjusted odds ratio (95% confidence interval): 2.11 (1.26; 3.61]). Our results emphasize the importance of understanding the interactions between drugs and UTs and those involving UT transporters in particular

The Role of Gut-Derived, Protein-Bound Uremic Toxins in the Cardiovascular Complications of Acute Kidney Injury

Acute kidney injury (AKI) is a frequent disease encountered in the hospital, with a higher incidence in intensive care units. Despite progress in renal replacement therapy, AKI is still associated with early and late complications, especially cardiovascular events and mortality. The role of gut-derived protein-bound uremic toxins (PBUTs) in vascular and cardiac dysfunction has been extensively studied during chronic kidney disease (CKD), in particular, that of indoxyl sulfate (IS), para-cresyl sulfate (PCS), and indole-3-acetic acid (IAA), resulting in both experimental and clinical evidence. PBUTs, which accumulate when the excretory function of the kidneys is impaired, have a deleterious effect on and cause damage to cardiovascular tissues. However, the link between PBUTs and the cardiovascular complications of AKI and the pathophysiological mechanisms potentially involved are unclear. This review aims to summarize available data concerning the participation of PBUTs in the early and late cardiovascular complications of AKI

Targeting the Unfolded Protein Response as a Potential Therapeutic Strategy in Renal Carcinoma Cells Exposed to Cyclosporine A

International audienceBackground/Aim: Organ transplant patients treated with the immunosuppressive drug cyclosporine A often present malignant kidney tumors. Cyclosporine A can promote oncogenesis in a cell-intrinsic manner by increasing the production of vascular endothelial growth factor (VEGF). Materials and Methods: We explored the impact of cyclosporine A and the role of the unfolded protein response (UPR) on three human renal cell carcinoma (RCC) cell lines under normoxic and hypoxic (1% O-2) conditions. Resullt:Cyclosporine A regulated the expression of VEGF at the post-transcriptional level. Cyclosporine A induced the inositol requiring enzyme-1 alpha (IRE1 alpha) arm of the UPR and stabilized neosynthesized proteins in RCC cells. Toyocamycin, an inhibitor of IRE1 alpha, abolished the clonogenic growth of RCC cells and reduced induction of VEGF by cyclosporine A under hypoxia. Conclusion: Our findings highlight the impact of cyclosporine A on the proteostasis of RCC cells, and suggest the potential therapeutic interest of targeting the UPR against tumors arising in the context of organ transplantation

Colchicine: An unusual but potential life threatening poisoning - about 3 cases

International audienceColchicine is an alkaloid used for treatment and prevention of acute gouty attacks and for other inflammatory diseases including Familial Mediterranean Fever or Behcet's disease. However, its toxicity limits its use. Colchicine poisoning is unusual but potentially life threatening. Colchicine toxicity is due to multi-organ failure, which can be fatal in the most severe cases, usually by cardiac or respiratory failure. Colchicine poisoning can be observed following an insufficient elimination, a drug interaction or a massive ingestion of colchicine. We report here 3 cases of acute poisoning occurring after a massive intake of colchicine in a suicide context. In the 3 cases, measurement of plasma concentrations of colchicine by liquid chromatography coupled to tandem mass spectrometry has confirmed the intoxication. In the most severe case, regular measurement of colchicine plasma concentrations has permitted to trace the evolution of intoxication. (C) 2015 Societe Francaise de Toxicologie Analytique. Published by Elsevier Masson SAS. All rights reserved

Early decrease in serum amphiregulin or vascular endothelial growth factor levels predicts sorafenib efficacy in hepatocellular carcinoma

International audienceSorafenib is the standard of care for the treatment of advanced hepatocellular carcinoma (HCC). However, identifying secreted biomarkers that predict sorafenib efficacy in all HCC patients remains challenging. It was recently reported that sorafenib interferes with protein homeostasis and inhibits global translation in tumour cells. A likely consequence of this inhibition would be the interruption of autocrine loops. The aim of the present study was to investigate the effect of sorafenib on two growth factors implicated in autocrine loops and HCC tumour invasion: amphiregulin (AREG) and vascular endothelial growth factor (VEGF). ELISA, quantitative polymerase chain reaction analysis, western blotting and a cytokine array were performed on HCC cell lines and the prognostic role of these two biomarkers in HCC patients was evaluated. Serum AREG and VEGF levels were assayed by ELISA in 55 patients with advanced HCC treated with sorafenib. It was observed that sorafenib decreased AREG, VEGF and cytokine expression at the transcriptional and post-transcriptional levels. All HCC patients in our cohort had detectable concentrations of AREG and VEGF both at baseline and after sorafenib treatment. The decreased serum levels of AREG and VEGF after 15 days of sorafenib treatment were significantly associated with better overall and progression-free survival. The results of the multivariate analysis demonstrated that a decrease in AREG was an independent prognostic indicator of overall survival (hazard ratio, 0.208; 95% confidence interval, 0.173-0.673; P=0.0003). These results suggest that sorafenib inhibits autocrine loops and that early decrease in serum AREG or VEGF levels predicts sorafenib efficacy in HCC patients