Le mélanome uvéal

Le mélanome uvéal est un cancer rare de l’adulte, dont les événements oncogéniques très stéréotypés ont été décryptés ces 10 dernières années. Ses particularités épidémiologiques, génétiques et transcriptionnelles en font un modèle remarquable de l’oncogenèse. La transformation maligne implique de façon presque mutuellement exclusive de grands processus biologiques, comme la régulation chromatinienne par inactivation de BAP1, l’épissage par mutations de SF3B1, et la traduction par mutations d’EIF1AX. L’étude du mélanome uvéal a permis de découvrir les mécanismes de l’épissage anormal lié aux mutations de SF3B1. La compréhension du lien entre ces anomalies et la transformation maligne sera la prochaine étape, dans l’espoir d’en déduire de nouvelles pistes thérapeutiques

Bapineuzumab for mild to moderate Alzheimer’s disease: a meta-analysis of randomized controlled trials

Abstract Background Alzheimer’s disease (AD) is a globally prevalent neurodegenerative condition, clinically characterized by progressive memory loss and gradual impairment of cognitive functions. Bapineuzumab is a fully humanized monoclonal antibody that binds to neurotoxic amyloid proteins in the brain, enhancing their clearance. We performed this systematic review and meta-analysis to evaluate the safety and efficacy of bapineuzumab in patients with mild to moderate Alzheimer’s disease. Methods We performed a web-based literature search of PubMed, Ovid, EBSCO, Scopus, Embase, Cochrane CENTRAL, and web of science using the relevant keywords. Data were extracted from eligible records and pooled as mean difference (MD) or risk ratio (RR) values with their 95% confidence interval (CI), using Review Manager software (version 5.3 for windows). Heterogeneity was measured by Chi-square and I-square tests. Result The pooled effect estimate from six randomized clinical trials (n = 2380) showed that bapineuzumab significantly reduced the cerebrospinal fluid concentration of phosphorylated tau proteins (Standardized MD = −5.53, 95% CI [−8.29, −2.76]). However, the bapineuzumab group was not superior to the placebo group in terms of change from baseline in Alzheimer’s disease assessment scale (ADAS)-Cog11 (MD = 0.14, 95% CI [−0.72, 0.99]), disability assessment for dementia (DAD) scale (MD = 1.35, 95% CI [−1.74, 4.43]), and mini-mental state examination (MMSE) scores (MD = 0.08, 95% CI [−0.31, 0.47]). Regarding safety, bapineuzumab increased the risk of serious treatment-emergent adverse events (RR = 1.18, 95% CI [1.02, 1.37]) and cerebral vasogenic edema (RR = 40.88, 95% CI [11.94, 135.95]). All bapineuzumab doses (0.15, 0.5, 1, and 2 mg/kg) were similar to placebo in terms of change from baseline in ADAS-cog11, DAD, and MMSE scores, except for the 0.15 mg/kg dose, which caused a significant worsening on the ADAS-cog11 scale (MD = 5.6, 95% CI [0.22, 10.98]). Conclusions Considering the lack of clinical efficacy, combined with the significant association with serious adverse events, bapineuzumab should not be used to treat patients with mild to moderate AD. Future studies should investigate the effect of combining bapineuzumab with other therapeutic strategies and reevaluate the efficacy of targeting amyloid β proteins in AD therapy

Genetic alterations of SUGP1 mimic mutant-SF3B1 splice pattern in lung adenocarcinoma and other cancers

International audienceGenes involved in 3′-splice site recognition during mRNA splicing constitute an emerging class of oncogenes. SF3B1 is the most frequently mutated splicing factor in cancer, and SF3B1 mutants corrupt branchpoint recognition leading to usage of cryptic 3′-splice sites and subsequent aberrant junctions. For a comprehensive determination of alterations leading to this splicing pattern, we performed a pan-TCGA screening for SF3B1-specific aberrant acceptor usage. While the most of aberrant 3′-splice patterns were explained by SF3B1 mutations, we also detected nine SF3B1 wild-type tumors (including five lung adenocarcinomas). Genomic profile analysis of these tumors identified somatic mutations combined with loss-of-heterozygosity in the splicing factor SUGP1 in five of these cases. Modeling of SUGP1 loss and mutations in cell lines showed that both alterations induced mutant-SF3B1-like aberrant splicing. Our study provides definitive evidence that genetic alterations of SUGP1 genocopy SF3B1 mutations in lung adenocarcinoma and other cancers

Patient-derived zebrafish xenografts of uveal melanoma reveal ferroptosis as a drug target

Uveal melanoma (UM) has a high risk to progress to metastatic disease with a median survival of 3.9 months after metastases detection, as metastatic UM responds poorly to conventional and targeted chemotherapy and is largely refractory to immunotherapy. Here, we present a patient-derived zebrafish UM xenograft model mimicking metastatic UM. Cells isolated from Xmm66 spheroids derived from metastatic UM patient material were injected into 2 days-old zebrafish larvae resulting in micro-metastases in the liver and caudal hematopoietic tissue. Metastasis formation could be reduced by navitoclax and more efficiently by the combinations navitoclax/everolimus and flavopiridol/quisinostat. We obtained spheroid cultures from 14 metastatic and 10 primary UM tissues, which were used for xenografts with a success rate of 100%. Importantly, the ferroptosis-related genes GPX4 and SLC7A11 are negatively correlated with the survival of UM patients (TCGA: n = 80; Leiden University Medical Centre cohort: n = 64), ferroptosis susceptibility is correlated with loss of BAP1, one of the key prognosticators for metastatic UM, and ferroptosis induction greatly reduced metastasis formation in the UM xenograft model. Collectively, we have established a patient-derived animal model for metastatic UM and identified ferroptosis induction as a possible therapeutic strategy for the treatment of UM patients

FAK Inhibitor-Based Combinations with MEK or PKC Inhibitors Trigger Synergistic Antitumor Effects in Uveal Melanoma

Uveal Melanoma (UM) is a rare and malignant intraocular tumor with dismal prognosis. Even if radiation or surgery permit an efficient control of the primary tumor, up to 50% of patients subsequently develop metastases, mainly in the liver. The treatment of UM metastases is challenging and the patient survival is very poor. The most recurrent event in UM is the activation of Gαq signaling induced by mutations in GNAQ/11. These mutations activate downstream effectors including protein kinase C (PKC) and mitogen-activated protein kinases (MAPK). Clinical trials with inhibitors of these targets have not demonstrated a survival benefit for patients with UM metastasis. Recently, it has been shown that GNAQ promotes YAP activation through the focal adhesion kinase (FAK). Pharmacological inhibition of MEK and FAK showed remarkable synergistic growth-inhibitory effects in UM both in vitro and in vivo. In this study, we have evaluated the synergy of the FAK inhibitor with a series of inhibitors targeting recognized UM deregulated pathways in a panel of cell lines. The combined inhibition of FAK and MEK or PKC had highly synergistic effects by reducing cell viability and inducing apoptosis. Furthermore, we demonstrated that these combinations exert a remarkable in vivo activity in UM patient-derived xenografts. Our study confirms the previously described synergy of the dual inhibition of FAK and MEK and identifies a novel combination of drugs (FAK and PKC inhibitors) as a promising strategy for therapeutic intervention in metastatic UM