Comparative analysis of canine and human melanomas

This paper presents epidemiological and clinical data from 2350 cases of melanocytic tumours from dogs sampled in France. In addition, we present the histological and genetic characterization of subsets of melanoma cases (n=153 and n=100, respectively), with a comparative aspect to human melanomas. Dog melanomas occur at the same anatomical sites than human melanomas, but with different frequency and severity. We demonstrate that the specificities of dog melanomas make them good models to understand the non-UV pathways of human melanomas. Interestingly, somatic mutations in oral canine melanomas were detected in the NRAS and PTEN genes, precisely at the same hotspots as human mutations. In contrast, mutations in the BRAF gene were not detected. This paper highlights the similarities and differences of dog and human melanoma types and the strong potential of dog melanomas to decipher the non-UV light pathways in different melanoma types, especially mucosal and acral types.Cet article présente les données épidémiologiques et cliniques de 2350 cas de tumeurs mélanocytaires canines collectées en France. Nous avons réalisé la caractérisation histologique (n = 153) et génétique (n = 100) d'un sous-groupe de mélanomes dont les résultats ont été comparés aux données des mélanomes humains. Les mélanomes apparaissent aux mêmes sites anatomiques chez le chien et l'Homme, mais avec des fréquences et des sévérités différentes. Nous montrons les prédispositions raciales des mélanomes canins et l'intérêt de ce modèle pour rechercher les gènes prédisposant difficiles à identifier chez l'Homme. Des mutations somatiques dans les gènes NRAS et PTEN ont été détectées dans les mélanomes buccaux canins, précisément aux mêmes points chauds (hotspots) que les mutations de ces gènes chez l'homme. Au contraire, aucune mutation dans le gène BRAF n'a été retrouvée dans les échantillons canins analysés. Ce travail met en lumière les homologies et différences entre les types de mélanomes humains et canins et démontre la force du modèle canin pour analyser les voies de signalisation non UV-dépendantes des mélanomes humains, particulièrement dans les types muqueux et acraux

Luminescent ruthenium(II) complexes used for the detection of 8oxoguanine in the human telomeric sequence

International audienceDetecting cancer at the early stage of the disease is crucial to keep the best chance for successful treatment. The recent development of genomic screening, a methodology that is addressed to asymptomatic patients presumably at risk of carcinogenesis, has stimulated the quest for new tools able to signal the level of risk. Carcinogenesis has been associated to chronic oxidative stress exceeding the antioxidant defenses and leading to critical genome alteration levels. The telomeric regions are presumably the most exposed to oxidative stress due to their high concentration of guanine (i.e. the easiest oxidizable nucleic base). Accumulation of 8-oxoguanine in telomeres, thus oxidative lesions, was reportedly associated with telomeric crisis and carcinogenesis. In this study, we report on the capacity of Ru(II) polyazaaromatic complexes to photoprobe 8-oxoguanine into the human telomeric sequence with the view of developing new tools for cancer risk screening

Luminescent ruthenium(II) complexes used for the detection of 8oxoguanine in the human telomeric sequence

International audienceDetecting cancer at the early stage of the disease is crucial to keep the best chance for successful treatment. The recent development of genomic screening, a methodology that is addressed to asymptomatic patients presumably at risk of carcinogenesis, has stimulated the quest for new tools able to signal the level of risk. Carcinogenesis has been associated to chronic oxidative stress exceeding the antioxidant defenses and leading to critical genome alteration levels. The telomeric regions are presumably the most exposed to oxidative stress due to their high concentration of guanine (i.e. the easiest oxidizable nucleic base). Accumulation of 8-oxoguanine in telomeres, thus oxidative lesions, was reportedly associated with telomeric crisis and carcinogenesis. In this study, we report on the capacity of Ru(II) polyazaaromatic complexes to photoprobe 8-oxoguanine into the human telomeric sequence with the view of developing new tools for cancer risk screening

Flexible RuII Schiff base complexes: G‐quadruplex DNA binding and photo‐induced cancer cell death

A series of new RuII Schiff base complexes built on the salphen moiety has been prepared. This includes four flexibile monometallic RuII compounds and six rigid bimetallic analogues that contain NiII, PdII or PtII cations into the salphen complexation site. Steady state luminescence titrations illustrated the capacity of the compounds to photoprobe G‐quadruplex DNA. Moreover, the vast array of the Schiff base structural changes allowed to extensively assess the influence of the ligand surface, flexibility and charge on the interaction of the compounds with G‐quadruplex DNA. This was achieved thanks to circular dichroism melting assays and bio‐layer interferometry studies that pointed up high affinities along with good selectivities of RuII Schiff base complexes for G4 DNA. In cellulo studies were carried out with the most promising compounds. Cellular uptake with location of the compounds in the nucleus as well as in the nucleolus was observed. Cell viability experiments were performed with U2OS osteosarcoma cells in the dark and under light irradiation which allowed the measurements of IC50’s and photoindexes. They showed the substantial role played by light irradiation in the activity of the drugs in addition to the low cytotoxicity of the molecules in the dark. Altogether, the reported results emphasize the promising properties of RuII Schiff base complexes as a new class of candidates for developing potential G4 DNA targeting diagnostic or therapeutic compounds

Photo-induced telomeric DNA damage in human cancer cells

International audienceHerein we report on the study of novel dinuclear ruthenium(II) complexes designed to target and to photo-react with G-quadruplex telomeric DNA. Upon irradiation, complexes efficiently generate guanine radical cation sites as photo-oxidation products. The compounds also display efficient cell penetration with localization to the nucleus and show strong photocytotoxicity toward osteosarcoma cells. Thanks to a microscopic-based telomere dysfunction assay, which allows the direct visualization of DNA damage in cells, we brought the first evidence of forming photo-oxidative damage at telomeres in cellulo. This emphasizes interesting prospects for the development of future cancer phototherapies

Micro-camera and micro-spectrometer designs adapted to large infrared focal plane arrays

International audienceToday's infrared focal plane arrays concentrate in a small volume of typically 1 cm3 the results of three decades of research in microelectronics and packaging. Several technological breakthroughs have already been achieved leading to the development of infrared focal plane arrays (IRFPA's) for high-performances applications requiring spatial and thermal resolution, also for low-cost and high-manufacturing volumes (technology of uncooled micro-bolometers). The next step is to reduce the optics and make it compatible with the successful IRFPA's fabrication technology. This paper presents some methods and technologies we are exploring for high-performance and small infrared systems. These developments have led to a tool box of micro-concepts described by an optical function (imagery or spectrometry) integrated in the vicinity of the IRFPA. For this, old optical concepts have been revisited (pinhole optics, Talbot effect) and first demonstrations of original IRFPA-based micro-optical assemblies will be given