Le FORUM, Vol. 37 No. 4

https://digitalcommons.library.umaine.edu/francoamericain_forum/1039/thumbnail.jp

Dimethyl Sulfoxide: A Bio-Friendly or Bio-Hazard Chemical? The Effect of DMSO in Human Fibroblast-like Synoviocytes

International audienceThe effect of dimethyl sulfoxide (DMSO) in rheumatoid arthritis (RA) human fibroblast-like synoviocytes (FLSs) has been studied on five different samples harvested from the joints (fingers, hands and pelvis) of five women with RA. At high concentrations (>5%), the presence of DMSO induces the cleavage of caspase-3 and PARP-1, two phenomena associated with the cell death mechanism. Even at a 0.5% concentration of DMSO, MTT assays show a strong toxicity after 24 h exposure (≈25% cell death). Therefore, to ensure a minimum impact of DMSO on RA FLSs, our study shows that the concentration of DMSO has to be below 0.05% to be considered saf

Combination of tetrapyridylporphyrins and arene ruthenium(II) complexes to treat synovial sarcoma by photodynamic therapy

International audienceFour tetrapyridylporphyrin and four dipyridylporphyrin arene ruthenium complexes have been synthesized and characterized. In these complexes, the porphyrin core is either metal-free or occupied by zinc, and the arene ligand of the arene ruthenium units are either the standard methyl-isopropyl-benzene ([Formula: see text]cymene) or the less common phenylpropanol (PhPrOH) derivative. The porphyrin derivatives are coordinated to four arene ruthenium units or only two, in accordance with the number of pyridyl substituents at the periphery of the porphyrins, 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine (TPyP) and 5,15-diphenyl-10,20-di(pyridin-4-yl)porphyrin (DPhDPyP). All eight complexes were evaluated as anticancer agents on synovial sarcoma cells, in the presence and absence of light, suggesting that both the arene ligand and the porphyrin core substituent can play a crucial role in fine-tuning the photodynamic activity of such organometallic photosensitizers

Ruthenium-based assemblies incorporating tetrapyridylporphyrin panels: A photosensitizers delivery strategy for the treatment of rheumatoid arthritis by photodynamic therapy

International audienceRuthenium-based assemblies containing tetrapyridylporphyrins (TPyP) in their structure have been evaluated as photosensitizers (PS) to treat rheumatoid arthritis (RA) by photodynamic therapy (PDT). TPyP is useless by itself as PS..

The Effect of Photosensitizer Metalation Incorporated into Arene–Ruthenium Assemblies on Prostate Cancer

Prostate cancer is the second most common cancer for men and a major health issue. Despite treatments, a lot of side effects are observed. Photodynamic therapy is a non-invasive method that uses photosensitizers and light to induce cell death through the intramolecular generation of reactive oxygen species, having almost no side effects. However, some of the PSs used in PDT show inherent low solubility in biological media, and accordingly, functionalization or vectorization is needed to ensure internalization. To this end, we have used arene–ruthenium cages in order to deliver PSs to cancer cells. These metalla-assemblies can host PSs inside their cavity or be constructed with PS building blocks. In this study, we wanted to determine if the addition of metals (Mg, Co, Zn) in the center of these PSs plays a role. Our results show that most of the compounds induce cytotoxic effects on DU 145 and PC-3 human prostate cancer cells. Localization by fluorescence confirms the internalization of the assemblies in the cytoplasm. An analysis of apoptotic processes shows a cleavage of pro-caspase-3 and poly-ADP-ribose polymerase, thus leading to a strong induction of DNA fragmentation. Finally, the presence of metals in the PS decreases PDT’s effect and can even annihilate it

Evaluation of Ruthenium-Based Assemblies as Carriers of Photosensitizers to Treat Rheumatoid Arthritis by Photodynamic Therapy

For the first time, ruthenium-based assemblies have been used as carriers for photosensitizers in the treatment of rheumatoid arthritis by photodynamic therapy (PDT). These metallacages are totally soluble in physiological media and can transport photosensitizers (PS) in their cavity. After an incubation period, the PS is released in the cytoplasm and irradiation can take place. This strategy allows photosensitizers with low or null solubility in biological media to be evaluated as PDT agents in rheumatoid arthritis. The systems in which 21H,23H-porphine and 29H,31H-phthalocyanine are encapsulated show excellent photocytotoxicity and no toxicity in the dark. On the other hand, systems in which metalated derivatives such as Mg(II)-porphine and Zn(II)-phthalocyanine are used show good photocytotoxicity, but to a lesser extent than the previous two. Furthermore, the presence of Zn(II)-phthalocyanine significantly increases the toxicity of the system. Overall, fifteen different host–guest systems have been evaluated, and based on the results obtained, they show high potential for treating rheumatoid arthritis by PDT

A Combination of Ruthenium Complexes and Photosensitizers to Treat Colorectal Cancer

Treatment regimens are regularly evolving alongside novel therapies and drugs. Such evolution is necessary to circumvent resistance mechanisms and to give patients the best possible health care. When dealing with cancer, most regimens involve multiple treatments (surgery, radiation therapy, chemotherapy, immunotherapy, etc.). The purpose of this study was to associate in a single compound metal-based drugs and photosensitizers to combine chemotherapy and photodynamic therapy. Two arene–ruthenium tetrapyridylporphyrin compounds (2H-TPyP-arene-Ru and Zn-TPyP-arene-Ru) have been synthesized and evaluated on two colorectal cancer cell lines (HCT116 and HT-29). Their cytotoxicity and phototoxicity have been evaluated. In addition, the anticancer mechanism and the cell death process mediated by the two compounds were studied. The results showed that the two arene–ruthenium photosensitizer-containing complexes have a strong phototoxic effect after photoactivation. The 2H-TPyP-arene-Ru complex induced outstanding cytotoxicity when compared to the Zn-TPyP-arene-Ru analogue. Moreover, under light, these two arene–ruthenium photosensitizers induce an apoptotic process in human colorectal cancer cell lines

Le monde des collectifs : enquêtes sur les recompositions du travail

International audienceLes recompositions du travail et de l’emploi, l’accumulation des réformes et les crises profondes – sociales, sanitaires, économiques – reposent la question de la possibilité même des collectifs de travail et d’emploi. Cet ouvrage interroge les nouvelles formes prises par ces collectifs, à rebours de l’idée que l’individualisation serait une tendance univoque. Les vingt-quatre auteur.e.s réunis ici – sociologues, juristes, ergonomes, économistes et politistes – s’affranchissent de toute définition a priori des collectifs. Ils privilégient une approche inductive, la pluralité des éclairages, des échelles et des époques à partir d’enquêtes de terrain approfondies. Les contributions étudient ces mutations contemporaines pour une variété de secteurs – la production cinématographique, l’aéronautique, les tiers lieux et les fablabs, l’hôpital, les services informatiques – et de publics – travailleurs et travailleuses d’un service social en entreprise, pilotes d’hélicoptères, travailleurs sociaux en Mission Locale, managers, secrétaires et assistantes de direction, salariés privés d’emploi et en transition professionnelle. Il ressort de ce panorama une mosaïque de collectifs dont les formes et les dynamiques rendent compte in fine de leurs capacités à se réinventer. [résumé éditeur