Ciblage thérapeutique de la voie Hippo pour le traitement des cancers mammaires chez la chienne

Les tumeurs mammaires canines sont les néoplasmes les plus courants chez les chiennes intactes, dont 50% sont malignes. La résection est le traitement standard pour les tumeurs mammaires canines, mais dans les cas inopérables tels que les carcinomes inflammatoires et les tumeurs métastatiques avancées, aucun traitement chimiothérapeutique efficace n'est disponible. L'étude de la pathogenèse des tumeurs mammaires canines aide à découvrir de nouvelles cibles thérapeutiques et des médicaments capables d'agir sur ces cibles pour traiter ce cancer. Des études récentes sur le dérèglement de la voie Hippo et de son rôle dans la tumorigenèse du cancer du sein, ainsi que les niveaux élevés de ces composants principaux dans les tumeurs mammaires canines, ont conduit à notre recherche sur la validation de cette voie comme cible pharmacologique pour le traitement des tumeurs des glandes mammaires canines. Six lignées de cellules tumorales mammaires canines ont été évaluées pour leur expression basale des effecteurs YAP et TAZ de la voie Hippo et pour leur sensibilité à la verteporfin, un inhibiteur de la co-activation transcriptionnelle engendrée par YAP. Quatre lignées cellulaires, qui ont des niveaux basaux détectables de YAP (CMT-9, -12, -28, -47), se sont révélées très sensibles au traitement à la verteporfin, qui a tué les cellules par induction d'apoptose avec des valeurs de ED50 de 14 à 79 nM. À l'inverse, deux lignées cellulaires qui n'exprimaient pas YAP (CF-35, CMT-84) étaient représentées par un ordre de grandeur plus résistant à la verteporfin. La verteporfin a supprimé l'expression des gènes cibles de YAP et TAZ, en particulier CYR61 et CTGF, qui jouent un rôle important dans le développement du cancer du sein. La verteporfin a également pu inhiber la migration cellulaire et la croissance indépendante de l'ancrage. De même, la verteporfin supprime efficacement le potentiel invasif des cellules tumorales dans les lignées CMT-28 et -47, mais pas dans les cellules CF-35. Ensemble, nos résultats fournissent une preuve de principe selon lequel le ciblage pharmacologique de la voie Hippo compromet la viabilité et atténue le comportement malin des cellules tumorales mammaires canines. Ces résultats serviront de base au développement de nouvelles approches chimiothérapeutiques pour les tumeurs mammaires canines qui pourraient être utilisées en médecine humaine.Canine mammary tumors are the most common neoplasms in intact female dogs with 50% of them being malignant tumours. Resection is the standard treatment for canine mammary tumours, but in inoperable cases such as inflammatory carcinomas and advanced metastatic tumours, no efficient chemotherapeutic treatment is available. Studying canine mammary tumour pathogenesis helps with the discovery of novel therapeutic targets and of drugs able to act on these targets to treat the cancer. Recent insight on the Hippo pathway deregulation and the role it plays in breast cancer tumorigenesis, as well as its presence in canine mammary tumours, has lead to our research for the validation of this pathway as a pharmacological target for the treatment of canine mammary gland tumors. Six canine mammary tumour cell lines were assessed for their basal expression of the Hippo pathway effectors YAP and TAZ, and for their sensitivity to verteporfin, an inhibitor of YAP-mediated transcriptional coactivation. Four cell lines that had detectable baseline levels of YAP (CMT-9, -12, -28, -47) were found to be very sensitive to verteporfin treatment, which killed the cells through induction of apoptosis with ED50 values of 14-79 nM. Conversely, two cell lines that did not have detectable levels of YAP (CF-35, CMT-84) were an order of magnitude more resistant to verteporfin. Verteporfin suppressed the expression of YAP and TAZ target genes, particularly CYR61 and CTGF, which play important roles in breast cancer development. Verteporfin was also able to inhibit cell migration and anchorage-independent growth. Likewise, verteporfin efficiently suppressed tumor cell invasiveness in the CMT-28 and -47 lines, but not in CF-35 cells. Together, our findings provide proof of principle that pharmacological targeting of the Hippo pathway compromises the viability and attenuates the malignant behavior of canine mammary tumour cells. These results will serve as the basis for the development of novel chemotherapeutic approaches for canine mammary tumors that could translate to human medicine

Bacterioplankton drawdown of coral mass-spawned organic matter

Coral reef ecosystems are highly sensitive to microbial activities that result from dissolved organic matter (DOM) enrichment of their surrounding seawater. However, the response to particulate organic matter (POM) enrichment is less studied. In a microcosm experiment, we tested the response of bacterioplankton to a pulse of POM from the mass-spawning of Orbicella franksi coral off the Caribbean coast of Panama. Particulate organic carbon (POC), a proxy measurement for POM, increased by 40-fold in seawater samples collected during spawning; 68% degraded within 66 h. The elevation of multiple hydrolases presumably solubilized the spawn-derived POM into DOM. A carbon budget constructed for the 275 µM of degraded POC showed negligible change to the concentration of dissolved organic carbon (DOC), indicating that the DOM was readily utilized. Fourier transform ion cyclotron resonance mass spectrometry shows that the DOM pool became enriched with heteroatom-containing molecules, a trend that suggests microbial alteration of organic matter. Our sensitivity analysis demonstrates that bacterial carbon demand could have accounted for a large proportion of the POC degradation. Further, using bromodeoxyuridine immunocapture in combination with 454 pyrosequencing of the 16S ribosomal RNA gene, we surmise that actively growing bacterial groups were the primary degraders. We conclude that coral gametes are highly labile to bacteria and that such large capacity for bacterial degradation and alteration of organic matter has implications for coral reef health and coastal marine biogeochemistry

Bacterioplankton drawdown of coral mass-spawned organic matter.

Coral reef ecosystems are highly sensitive to microbial activities that result from dissolved organic matter (DOM) enrichment of their surrounding seawater. However, the response to particulate organic matter (POM) enrichment is less studied. In a microcosm experiment, we tested the response of bacterioplankton to a pulse of POM from the mass-spawning of Orbicella franksi coral off the Caribbean coast of Panama. Particulate organic carbon (POC), a proxy measurement for POM, increased by 40-fold in seawater samples collected during spawning; 68% degraded within 66 h. The elevation of multiple hydrolases presumably solubilized the spawn-derived POM into DOM. A carbon budget constructed for the 275 µM of degraded POC showed negligible change to the concentration of dissolved organic carbon (DOC), indicating that the DOM was readily utilized. Fourier transform ion cyclotron resonance mass spectrometry shows that the DOM pool became enriched with heteroatom-containing molecules, a trend that suggests microbial alteration of organic matter. Our sensitivity analysis demonstrates that bacterial carbon demand could have accounted for a large proportion of the POC degradation. Further, using bromodeoxyuridine immunocapture in combination with 454 pyrosequencing of the 16S ribosomal RNA gene, we surmise that actively growing bacterial groups were the primary degraders. We conclude that coral gametes are highly labile to bacteria and that such large capacity for bacterial degradation and alteration of organic matter has implications for coral reef health and coastal marine biogeochemistry

Long-term safety and efficacy of patisiran for hereditary transthyretin-mediated amyloidosis with polyneuropathy: 12-month results of an open-label extension study

© 2020 Elsevier Ltd. All rights reserved.Background: Hereditary transthyretin-mediated amyloidosis is a rare, inherited, progressive disease caused by mutations in the transthyretin (TTR) gene. We assessed the safety and efficacy of long-term treatment with patisiran, an RNA interference therapeutic that inhibits TTR production, in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy. Methods: This multicentre, open-label extension (OLE) trial enrolled patients at 43 hospitals or clinical centres in 19 countries as of Sept 24, 2018. Patients were eligible if they had completed the phase 3 APOLLO or phase 2 OLE parent studies and tolerated the study drug. Eligible patients from APOLLO (patisiran and placebo groups) and the phase 2 OLE (patisiran group) studies enrolled in this global OLE trial and received patisiran 0·3 mg/kg by intravenous infusion every 3 weeks with plans to continue to do so for up to 5 years. Efficacy assessments included measures of polyneuropathy (modified Neuropathy Impairment Score +7 [mNIS+7]), quality of life, autonomic symptoms, nutritional status, disability, ambulation status, motor function, and cardiac stress, with analysis by study groups (APOLLO-placebo, APOLLO-patisiran, phase 2 OLE patisiran) based on allocation in the parent trial. The global OLE is ongoing with no new enrolment, and current findings are based on the interim analysis of the patients who had completed 12-month efficacy assessments as of the data cutoff. Safety analyses included all patients who received one or more dose of patisiran up to the data cutoff. This study is registered with ClinicalTrials.gov, NCT02510261. Findings: Between July 13, 2015, and Aug 21, 2017, of 212 eligible patients, 211 were enrolled: 137 patients from the APOLLO-patisiran group, 49 from the APOLLO-placebo group, and 25 from the phase 2 OLE patisiran group. At the data cutoff on Sept 24, 2018, 126 (92%) of 137 patients from the APOLLO-patisiran group, 38 (78%) of 49 from the APOLLO-placebo group, and 25 (100%) of 25 from the phase 2 OLE patisiran group had completed 12-month assessments. At 12 months, improvements in mNIS+7 with patisiran were sustained from parent study baseline with treatment in the global OLE (APOLLO-patisiran mean change -4·0, 95 % CI -7·7 to -0·3; phase 2 OLE patisiran -4·7, -11·9 to 2·4). Mean mNIS+7 score improved from global OLE enrolment in the APOLLO-placebo group (mean change from global OLE enrolment -1·4, 95% CI -6·2 to 3·5). Overall, 204 (97%) of 211 patients reported adverse events, 82 (39%) reported serious adverse events, and there were 23 (11%) deaths. Serious adverse events were more frequent in the APOLLO-placebo group (28 [57%] of 49) than in the APOLLO-patisiran (48 [35%] of 137) or phase 2 OLE patisiran (six [24%] of 25) groups. The most common treatment-related adverse event was mild or moderate infusion-related reactions. The frequency of deaths in the global OLE was higher in the APOLLO-placebo group (13 [27%] of 49), who had a higher disease burden than the APOLLO-patisiran (ten [7%] of 137) and phase 2 OLE patisiran (0 of 25) groups. Interpretation: In this interim 12-month analysis of the ongoing global OLE study, patisiran appeared to maintain efficacy with an acceptable safety profile in patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy. Continued long-term follow-up will be important for the overall assessment of safety and efficacy with patisiran.info:eu-repo/semantics/publishedVersio