30 research outputs found
Melanoma Chemotherapy Leads to the Selection of ABCB5-Expressing Cells
Metastatic melanoma is the most aggressive skin cancer. Recently, phenotypically distinct subpopulations of tumor cells were identified. Among them, ABCB5-expressing cells were proposed to display an enhanced tumorigenicity with stem cell-like properties. In addition, ABCB5+ cells are thought to participate to chemoresistance through a potential efflux function of ABCB5. Nevertheless, the fate of these cells upon drugs that are used in melanoma chemotherapy remains to be clarified. Here we explored the effect of anti-melanoma treatments on the ABCB5-expressing cells. Using a melanoma xenograft model (WM266-4), we observed in vivo that ABCB5-expressing cells are enriched after a temozolomide treatment that induces a significant tumor regression. These results were further confirmed in a preliminary study conducted on clinical samples from patients that received dacarbazine. In vitro, we showed that ABCB5-expressing cells selectively survive when exposed to dacarbazine, the reference treatment of metastatic melanoma, but also to vemurafenib, a new inhibitor of the mutated kinase V600E BRAF and other various chemotherapeutic drugs. Our results show that anti-melanoma chemotherapy might participate to the chemoresistance acquisition by selecting tumor cell subpopulations expressing ABCB5. This is of particular importance in understanding the relapses observed after anti-melanoma treatments and reinforces the interest of ABCB5 and ABCB5-expressing cells as potential therapeutic targets in melanoma
Identification d'ARNs non-codants impliqués dans les dystrophinopathies
Duchenne (DMD) and Becker (BMD) muscular dystrophies are due to mutations in DMD gene, encoding Dystrophin. Many aspects of pathophysiological mechanisms of these diseases are not yet well understood. We were interested in the study of non-coding RNAs that could be involved in these pathological processes. A first study focused on micro-RNAs (miRNAs) that could modulate expression of the neuronal nitric oxide synthase (nNOS), a partner of Dystrophin which is linked to pathological features as muscular fatigability. 617 miRNAs were screened by Taqman Low Density Array in muscle biopsies of healthy subjects or BMDdel45-55 patients. 4 candidate miRNAs were selected from this study since they were overexpressed in BMDdel45-55 patients and for their theoretical ability to target nNOS. Experiments modulating the expression of these miRNAs in healthy or dystrophic human myoblasts enabled us to identify that miR-708-5p and miR-34-5p could target nNOS and modulate its expression.A second axis was conducted on long non-coding RNA (lncRNA). Introns 44 and 55, which bound exons 45-55 deleted in BMDdel45-55 patients, are large regions containing lncRNAs described as regulating Dystrophin. Since intronic breakpoints of DMD mutations of these pateints were not described, we have assumed the existence of different profiles of lncRNAs. DNA analysis of these patients actually showed different lncRNAs profiles, thus revealing the significance of a more precise analysis of deletion areas in DMD gene of BMDdel45-55 patients.Les dystrophies musculaires de Duchenne (DMD) et de Becker (BMD) sont dues Ă des mutations dans le gĂšne DMD codant la Dystrophine. De nombreux aspects des mĂ©canismes pathophysiologiques de ces maladies ne sont pas encore expliquĂ©s. Nous nous sommes intĂ©ressĂ©s Ă l'Ă©tude d'ARN non-codants pouvant participer Ă ces processus. Une premiĂšre Ă©tude a Ă©tĂ© centrĂ©e sur lâidentification de micro-ARNs (miARNs) impliquĂ©s dans la rĂ©gulation de lâoxyde nitrique synthase neuronale (nNOS) une protĂ©ine partenaire de la Dystrophine et associĂ©e Ă des caractĂ©ristiques de ces pathologies telles que la fatigabilitĂ© musculaire. 617 miARNs ont Ă©tĂ© criblĂ©s par Taqman Low Density Array dans des muscles de sujets sains et de patients BMDdel45-55. 4 miARNs candidats ont Ă©tĂ© sĂ©lectionnĂ©s de cette Ă©tude pour leur surexpression chez les patients BMDdel45-55 et leur capacitĂ© thĂ©orique Ă cibler nNOS. Des expĂ©riences de modulation de lâexpression de ces miARNs dans des myoblastes humains sains ou dystrophiques nous ont permis dâidentifier que le miR-708-5p et le miR-34-5p pouvaient cibler nNOS et moduler son expression.Un deuxiĂšme axe a Ă©tĂ© menĂ© sur lâĂ©tude des longs ARNs non-codants (lncARNs). Les introns 44 et 55, qui bornent les exons 45 Ă 55 dĂ©lĂ©tĂ©s chez les patients BMDdel45-55, sont de grandes rĂ©gions contenant des lncARNs dĂ©crits comme rĂ©gulant la Dystrophine. Les points de cassure introniques des mutations de ces patients nâĂ©tant pas dĂ©crites, nous avons supposĂ© lâexistence de profils de lncARNs diffĂ©rents. Lâanalyse de lâADN de ces patients montre en effet des profils de lncARNs diffĂ©rents, rĂ©vĂ©lant ainsi lâimportance dâune Ă©tude plus prĂ©cise des zones de dĂ©lĂ©tion des patients BMDdel45-55
Identification of non-coding RNAs involved in dystrophinopathies
Les dystrophies musculaires de Duchenne (DMD) et de Becker (BMD) sont dues Ă des mutations dans le gĂšne DMD codant la Dystrophine. De nombreux aspects des mĂ©canismes pathophysiologiques de ces maladies ne sont pas encore expliquĂ©s. Nous nous sommes intĂ©ressĂ©s Ă l'Ă©tude d'ARN non-codants pouvant participer Ă ces processus. Une premiĂšre Ă©tude a Ă©tĂ© centrĂ©e sur lâidentification de micro-ARNs (miARNs) impliquĂ©s dans la rĂ©gulation de lâoxyde nitrique synthase neuronale (nNOS) une protĂ©ine partenaire de la Dystrophine et associĂ©e Ă des caractĂ©ristiques de ces pathologies telles que la fatigabilitĂ© musculaire. 617 miARNs ont Ă©tĂ© criblĂ©s par Taqman Low Density Array dans des muscles de sujets sains et de patients BMDdel45-55. 4 miARNs candidats ont Ă©tĂ© sĂ©lectionnĂ©s de cette Ă©tude pour leur surexpression chez les patients BMDdel45-55 et leur capacitĂ© thĂ©orique Ă cibler nNOS. Des expĂ©riences de modulation de lâexpression de ces miARNs dans des myoblastes humains sains ou dystrophiques nous ont permis dâidentifier que le miR-708-5p et le miR-34-5p pouvaient cibler nNOS et moduler son expression.Un deuxiĂšme axe a Ă©tĂ© menĂ© sur lâĂ©tude des longs ARNs non-codants (lncARNs). Les introns 44 et 55, qui bornent les exons 45 Ă 55 dĂ©lĂ©tĂ©s chez les patients BMDdel45-55, sont de grandes rĂ©gions contenant des lncARNs dĂ©crits comme rĂ©gulant la Dystrophine. Les points de cassure introniques des mutations de ces patients nâĂ©tant pas dĂ©crites, nous avons supposĂ© lâexistence de profils de lncARNs diffĂ©rents. Lâanalyse de lâADN de ces patients montre en effet des profils de lncARNs diffĂ©rents, rĂ©vĂ©lant ainsi lâimportance dâune Ă©tude plus prĂ©cise des zones de dĂ©lĂ©tion des patients BMDdel45-55.Duchenne (DMD) and Becker (BMD) muscular dystrophies are due to mutations in DMD gene, encoding Dystrophin. Many aspects of pathophysiological mechanisms of these diseases are not yet well understood. We were interested in the study of non-coding RNAs that could be involved in these pathological processes. A first study focused on micro-RNAs (miRNAs) that could modulate expression of the neuronal nitric oxide synthase (nNOS), a partner of Dystrophin which is linked to pathological features as muscular fatigability. 617 miRNAs were screened by Taqman Low Density Array in muscle biopsies of healthy subjects or BMDdel45-55 patients. 4 candidate miRNAs were selected from this study since they were overexpressed in BMDdel45-55 patients and for their theoretical ability to target nNOS. Experiments modulating the expression of these miRNAs in healthy or dystrophic human myoblasts enabled us to identify that miR-708-5p and miR-34-5p could target nNOS and modulate its expression.A second axis was conducted on long non-coding RNA (lncRNA). Introns 44 and 55, which bound exons 45-55 deleted in BMDdel45-55 patients, are large regions containing lncRNAs described as regulating Dystrophin. Since intronic breakpoints of DMD mutations of these pateints were not described, we have assumed the existence of different profiles of lncRNAs. DNA analysis of these patients actually showed different lncRNAs profiles, thus revealing the significance of a more precise analysis of deletion areas in DMD gene of BMDdel45-55 patients
Implication des cellules exprimant le transporteur ABCB5 dans la chimiorésistance du mélanome métastatique
TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF
On-Farm Welfare Assessment of Horses: The Risks of Putting the Cart before the Horse
International audienceAlthough the question of animal welfare has been an important source of concern in the scientific community for several decades, many aspects are still under debate. On-farm assessments have to be rapid, acceptable to farmers and safe for both the assessors and animals. They are thus very demanding, with multiple decisions to make, such as the choice of appropriate indicators, sampling methods and scoring. Research has moved from resource-based to animal-based criteria, which reflects the subjective welfare state of an animal rather than relying upon external indices. In the present review, we describe two major (i.e., the most frequently/recently tested or disseminated) protocols: one in low-/middle-income countries, and the other in high-income countries, for on-farm assessments of horses, using animal-based resources; we evaluate their strengths and limitations, and then we compare their results with those obtained by various other studies. We propose lines of improvement, particularly in view of public dissemination, and offer suggestions for further refinement or new protocols. We emphasize the high risks of putting the cart before the horse, i.e., proposing protocols that rely upon indicators and sampling methods that need to be refined, as this could lead to under-evaluation (or less likely over-evaluation) of current welfare problems. Because welfare is a subjective experience, the true representation of an individual's actual welfare status has to be evaluated by using objective assessment tools (that are validated and have a scientific basis) used by well-trained observers
Palladium-catalyzed heteroaryl thioethers synthesis overcoming palladium dithiolate resting states inertness: Practical road to sulfones and N H-sulfoximines
International audienceWe provide efficient synthetic access to heteroaryl sulfones in two-steps using a simple palladium-1,1'-bis [(diphenyl)phosphanyl]ferrocene catalyst to form in high yields variously functionalized heteroaromatic thioethers. Pyridinyl-containing substrates can be subsequently selectively oxidized into sulfones and NH-sulfoximines by using very mild oxidation conditions with a high functional group tolerance. In the palladium catalyzed C-S coupling of heteroaromatic thiols, reactivity limitation is attached with electron-deficient thiols. We show that this limitation can be resolved by the successful use of 2-bromoheteroarenes in the C-S coupling. We established herein that this choice of heteroaryl electrophilic reagent in palladium-catalyzed C-S bond formation allows overcoming palladium dithiolate out-of-cycle resting state inertness. This was illustrated in the stoichiometric reactivity study of the palladium dithiolate formed from 4-trifluoromethylbenzen-1-thiol-isolated and characterized by multinuclear NMR and XRD-with both 2-chloropyridine and 2-bromopyridine
(2-Pyridyl)sulfonyl Groups for ortho -Directing Palladium- Catalyzed Carbon-Halogen Bond Formation at Functionalized Arenes
International audienceWe describe an efficient palladium-catalyzed selective C-H ortho-monohalogenation (X=I, Br, Cl, F) of various functionalized (2-pyridyl) aryl-sulfones. ortho-, meta-and para-functionalization is tolerated at the arene group which undergoes C-H halogenation. Some modifications are also possible on the 2-(arylsulfonyl) heteroaryl directing groups. A comparison of the halogenation efficiency suggests that bromination is the practical method of choice, while chlorination and fluorination are possible but more challenging. Under forcing conditions ortho-dihalogenation can also be achieved
Interest in Humans: Comparisons between Riding School Lesson Equids and Assisted-Intervention Equids
International audienceLittle is known about the impact of equine-assisted interventions (EAI) on equidsâ perception of humans. In this study 172 equids, living in 12 riding centres, were submitted to a standardised human-horse relationship test: the motionless person test. Age, sex, type (horse/pony), housing, and feeding conditions of subjects were recorded. Overall, 17 equids worked in EAI, 95 in riding school lessons (RS), and 60 in both (EAI-RS). There were high inter-individual variations in the number of interactive behaviours directed towards the experimenter: negative binomial general linear models showed that activity was the most important factor: RS equids performed more interactive behaviours than EAI (p = 0.039) and EAI-RS (p < 0.001) equids. Daily quantity of hay appeared as the second most important factor (equids with more than 3 kg interacted more than equids with less than 3 kg, p = 0.013). Individual characteristics were also important as horses interacted more than ponies (p = 0.009), geldings more than mares (p = 0.032), and 3-15-year-old equids more than equids over 15 years (p = 0.032). However, there was no interaction between factors. The lower number of interactive behaviours of EAI equids leads to different hypotheses-namely, selection on temperament, specific training, or compromised welfare (apathy). In any case, our results raised new lines of questions on EAI
Des chevaux de médiation moins interactifs, un constat
International audienceLa mĂ©diation Ă©quine est une activitĂ© de plus en plus rĂ©pandue. Sâil est gĂ©nĂ©ralement admis que ces activitĂ©s ont un impact positif sur les bĂ©nĂ©ficiaires, il y a Ă ce jour trĂšs peu dâĂ©lĂ©ments sur la perception quâont les chevaux de ces activitĂ©s. Dans cette Ă©tude, 185 chevaux pratiquant des activitĂ©s de mĂ©diation, de façon principale ou secondaire, ou pratiquant des activitĂ©s de centre Ă©questre « classiques » ont passĂ© un test standardisĂ© permettant dâĂ©valuer leur relation Ă lâHomme. Le principal constat qui ressort de cette Ă©tude est que les chevaux de mĂ©diation sont moins interactifs envers lâHomme. Plusieurs hypothĂšses explicatives peuvent ĂȘtre avancĂ©es: il sâagit (1) soit dâune caractĂ©ristique de tempĂ©rament ayant amenĂ© Ă un choix prĂ©fĂ©rentiel de ce type de chevaux pour ces activitĂ©s, (2) soit du rĂ©sultat dâun entraĂźnement Ă rester « neutre » et «calme» face Ă un humain qui peut avoir des comportements inhabituels, ou (3) soit de lâexpression dâune «rĂ©signation acquise» ou dâapathie. Dans ce cas, cela suggĂ©rerait que lâactivitĂ© de mĂ©diation est source de tensions Ă©motionnelles ou physiques. Seules des Ă©tudes plus dĂ©taillĂ©es sur le comportement des chevaux pendant les sĂ©ances de mĂ©diation et de leur bien-ĂȘtre permettront de rĂ©pondre Ă ces questions
miR-708-5p and miR-34c-5p are involved in nNOS regulation in dystrophic context
International audienceBackground: Duchenne (DMD) and Becker (BMD) muscular dystrophies are caused by mutations in the DMD gene coding for dystrophin, a protein being part of a large sarcolemmal protein scaffold that includes the neuronal nitric oxide synthase (nNOS). The nNOS was shown to play critical roles in a variety of muscle functions and alterations of its expression and location in dystrophic muscle fiber leads to an increase of the muscle fatigability. We previously revealed a decrease of nNOS expression in BMD patients all presenting a deletion of exons 45 to 55 in the DMD gene (BMDd45-55), impacting the nNOS binding site of dystrophin. Since several studies showed deregulation of microRNAs (miRNAs) in dystrophinopathies, we focused on miRNAs that could target nNOS in dystrophic context.Methods: By a screening of 617 miRNAs in BMDd45-55 muscular biopsies using TLDA and an in silico study to determine which one could target nNOS, we selected four miRNAs. In order to select those that targeted a sequence of 3âČUTR of NOS1, we performed luciferase gene reporter assay in HEK393T cells. Finally, expression of candidate miRNAs was modulated in control and DMD human myoblasts (DMDd45-52) to study their ability to target nNOS.Results: TLDA assay and the in silico study allowed us to select four miRNAs overexpressed in muscle biopsies of BMDd45-55 compared to controls. Among them, only the overexpression of miR-31, miR-708, and miR-34c led to a decrease of luciferase activity in an NOS1-3âČUTR-luciferase assay, confirming their interaction with the NOS1-3âČUTR. The effect of these three miRNAs was investigated on control and DMDd45-52 myoblasts. First, we showed a decrease of nNOS expression when miR-708 or miR-34c were overexpressed in control myoblasts. We then confirmed that DMDd45-52 cells displayed an endogenous increased of miR-31, miR-708, and miR-34c and a decreased of nNOS expression, the same characteristics observed in BMDd45-55 biopsies. In DMDd45-52 cells, we demonstrated that the inhibition of miR-708 and miR-34c increased nNOS expression, confirming that both miRNAs can modulate nNOS expression in human myoblasts.Conclusion: These results strongly suggest that miR-708 and miR-34c, overexpressed in dystrophic context, are new actors involved in the regulation of nNOS expression in dystrophic muscle