Immunogenicity Testing of Lipidoids In Vitro and In Silico: Modulating Lipidoid-Mediated TLR4 Activation by Nanoparticle Design.

Therapeutics based on small interfering RNA (siRNA) have promising potential as antiviral and anti-inflammatory agents. To deliver siRNA across cell membranes to reach the RNAi pathway in the cytosol of target cells, non-viral nanoparticulate delivery approaches are explored. Recently, we showed that encapsulation of siRNA in lipid-polymer hybrid nanoparticles (LPNs), based on poly(DL-lactic-co-glycolic acid) (PLGA) and cationic lipid-like materials (lipidoids), remarkably enhances intracellular delivery of siRNA as compared to siRNA delivery with LPNs modified with dioleoyltrimethylammoniumpropane (DOTAP) as the lipid component. However, the potential immune modulation by these cationic lipids remains unexplored. By testing lipidoids and DOTAP for innate immune-receptor-activating properties in vitro, we found that neither lipidoids nor DOTAP activate human Toll-like receptor (TLR) 2, 3, 7, and 9. However, in contrast to DOTAP, lipidoids are strong agonists for TLR4 and activate murine antigen-presenting cells in vitro. This agonistic effect was further confirmed in silico using a prediction model based on crystal structures. Also, lipidoids formulated as lipoplexes or as stable nucleic acid lipid particles, which was the reference formulation for siRNA delivery, proved to activate TLR4. However, by combining lipidoids with PLGA into LPNs, TLR4 activation was abrogated. Thus, lipidoid-mediated TLR4 activation during siRNA delivery may be modulated via optimization of the formulation design

Étude des marqueurs prédictifs de la réponse au Cetuximab chez les patients traités pour un cancer colorectal métastasique

Objectif : Évaluer l'impact des mutations somatiques de TP53 en combinaison avec les-mutations de KRAS sur l'évolution clinique des patients traités par cetuximab plus chimiothérapie pour un cancer colorectal métastatique (CCRM). Matériels et Méthodes :- étude retrospective incluant 64 patients traités par cetuximah pour un CCRM. La recherche des mutations a été effectuée dans la tumeur par séquençage direct des exons 5 à 8 pour TP53 et par la technique du SnaPshot pour KRAS. L'analyse a été complétée par le génotypage de BRAF et PIK3CA pour 49 patients et par l'évaluation du nombre de copies de l'EGFR par FISH pour 47 patients La réponse clinique a été corrélée aux statuts mutationnels par le test de Fisher. Les survies sans progression (SSP) ont été calculées selon la. méthode de Kaplan Meier et comparées par le test du log-rank. Résultats : une mutation de KRAS a été trouvée chez 18 des 64 patients (28 %). Ces mutations étaient significativement associées à la résistance au traitement. Une mutation de TP53 a été retrouvée chez 41 des 64 patients (64 %). Dans la population totale de l'étude et dans le sous-groupe de 46 patients KRAS sauvage, les mutations de TP53 étaient significativement associées au contrôle de la maladie (p=0,037 et p=0,008 , respectivement). Des mutations de BRAF, de PIK3CA et une augmentation du nombre de copies de l'EGFR ont été retrouvées chez 4 %, 11 % et 19 % des patients, sans association significative avec l'évolution clinique des patients. Conclusion : notre étude suggère que, chez les patients présentant un CCRM, les mutations de TP53 sont prédictives d'une plus grande sensibilité au cetuximab, en particulier en l'absence de mutation de KRAS. Le génotypage de TP53 pourrait avoir une valeur additionnelle chez les patients KRAS sauvages pour optimiser la sélection des patients susceptibles de bénéficier des thérapies ciblées anti-EGFR.ROUEN-BU Médecine-Pharmacie (765402102) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Our challenge is to adapt the organization of our system to the six stages of the epidemic to go beyond the COVID-19 crisis

International audienc

Clinical value of chip-based digital-PCR platform for the detection of circulating DNA in metastatic colorectal cancer

International audienc

COVID-19 epidemic Proposed alternatives in the management of digestive cancers A French intergroup clinical point of view (SNFGE, FFCD, GERCOR, UNICANCER, SFCD, SFED, SFRO, SFR)

International audienceIntroduction - Patients treated for malignancy are considered at risk of severe COVID-19. This exceptional pandemic has affected countries on every level, particularly health systems which are experiencing saturation. Like many countries, France is currently greatly exposed, and a complete reorganization of hospitals is ongoing. We propose here adaptations of diagnostic procedures, therapies and care strategies for patients treated for digestive cancer during the COVID-19 epidemic. Methods - French societies of gastroenterology and gastrointestinal (GI) oncology carried out this study to answer two main questions that have arisen (i) how can we limit high-risk situations for GI-cancer patients and (ii) how can we limit contact between patients and care centers to decrease patients' risk of contamination while continuing to treat their cancer. All recommendations are graded as experts' agreement according to the level of evidence found in the literature until March 2020. Results - A proposal to adapt treatment strategies was made for the main GI oncology situations. Considering the level of evidence and the heterogeneous progression of the COVID-19 epidemic, all proposals need to be considered by a multidisciplinary team and implemented with patient consent. Conclusion - COVID-19 epidemic may significantly affect patients treated for digestive malignancies. Healthcare teams need to consider adapting treatment sequences when feasible and according to the epidemic situation

Circulating DNA changes are predictive of disease progression after transarterial chemoembolization

International audienceTransarterial chemoembolization (TACE) is used to treat patients with unresectable hepatocellular carcinoma (HCC). We evaluated the clinical impact of a-fetoprotein (AFP) and circulating cell-free and tumor DNA (cfDNA and ctDNA) changes around the TACE procedure. Our prospective monocentric study enrolled consecutive patients treated with TACE, with samples collected at baseline (D - 1), Day 2 (D + 2) and 1 month (M + 1) after TACE. cfDNA was quantified by the fluorometric method, and ctDNA was quantified by digital polymerase chain reaction designed for two hotspot TERT mutations. Computerized tomography scans or magnetic resonance imaging were performed at M + 1 every 3 months following TACE and independently reviewed. The objective was to identify thresholds of cfDNA, ctDNA and AFP changes associated with progressive disease (PD) using receiver operating characteristic curves. Thirty-eight patients were included from March 2018 to March 2019. All markers significantly increased from D - 1 to D + 2 (P +31.4%] vs 3.8% [≤+31.4%] and 50.0% [>0%] vs 5.0% [≤0%], respectively). No significant threshold was identified for AFP. Using a score combining cfDNA and ctDNA, the patients were classified into high- or low-risk PD groups at M + 1, with PD rates of 80.0% vs 4.3% (P = .001) and median progression-free survival times of 1.3 vs 10.3 months (P = .002). Our study suggests that cfDNA and ctDNA increases around the TACE procedure and are associated with therapeutic failure

Immunogenicity Testing of Lipidoids In Vitro and In Silico: Modulating Lipidoid-Mediated TLR4 Activation by Nanoparticle Design

Therapeutics based on small interfering RNA (siRNA) have promising potential as antiviral and anti-inflammatory agents. To deliver siRNA across cell membranes to reach the RNAi pathway in the cytosol of target cells, non-viral nanoparticulate delivery approaches are explored. Recently, we showed that encapsulation of siRNA in lipid-polymer hybrid nanoparticles (LPNs), based on poly(DL-lactic-co-glycolic acid) (PLGA) and cationic lipid-like materials (lipidoids), remarkably enhances intracellular delivery of siRNA as compared to siRNA delivery with LPNs modified with dioleoyltrimethylammoniumpropane (DOTAP) as the lipid component. However, the potential immune modulation by these cationic lipids remains unexplored. By testing lipidoids and DOTAP for innate immune-receptor-activating properties in vitro, we found that neither lipidoids nor DOTAP activate human Toll-like receptor (TLR) 2, 3, 7, and 9. However, in contrast to DOTAP, lipidoids are strong agonists for TLR4 and activate murine antigen-presenting cells in vitro. This agonistic effect was further confirmed in silico using a prediction model based on crystal structures. Also, lipidoids formulated as lipoplexes or as stable nucleic acid lipid particles, which was the reference formulation for siRNA delivery, proved to activate TLR4. However, by combining lipidoids with PLGA into LPNs, TLR4 activation was abrogated. Thus, lipidoid-mediated TLR4 activation during siRNA delivery may be modulated via optimization of the formulation design