Orthotopic model of lung cancer: isolation of bone micro-metastases after tumor escape from Osimertinib treatment.

BACKGROUND: Osimertinib is a third generation tyrosine kinase inhibitor (TKI) that targets the epidermal growth factor receptor (EGFR) in lung cancer. However, although this molecule is not subject to some of the resistance mechanisms observed in response to first generation TKIs, ultimately, patients relapse because of unknown resistance mechanisms. New relevant non-small cell lung cancer (NSCLC) mice models are therefore required to allow the analysis of these resistance mechanisms and to evaluate the efficacy of new therapeutic strategies. METHODS: Briefly, PC-9 cells, previously modified for luciferase expression, were injected into the tail vein of mice. Tumor implantation and longitudinal growth, almost exclusively localized in the lung, were evaluated by bioluminescence. Once established, the tumor was treated with osimertinib until tumor escape and development of bone metastases. RESULTS: Micro-metastases were detected by bioluminescence and collected for further analysis. CONCLUSION: We describe an orthotopic model of NSCLC protocol that led to lung primary tumor nesting and, after osimertinib treatment, by metastases dissemination, and that allow the isolation of these small osimertinib-resistant micro-metastases. This model provides new biological tools to study tumor progression from the establishment of a lung tumor to the generation of drug-resistant micro-metastases, mimicking the natural course of the disease in human NSCLC patients.

Anti-apoptotic role of caspase-cleaved GAB1 adaptor protein in hepatocyte growth factor/scatter factor-MET receptor protein signaling.

The GRB2-associated binder 1 (GAB1) docking/scaffold protein is a key mediator of the MET-tyrosine kinase receptor activated by hepatocyte growth factor/scatter factor (HGF/SF). Activated MET promotes recruitment and tyrosine phosphorylation of GAB1, which in turn recruits multiple proteins and mediates MET signaling leading to cell survival, motility, and morphogenesis. We previously reported that, without its ligand, MET is a functional caspase target during apoptosis, allowing the generation of a p40-MET fragment that amplifies apoptosis. In this study we established that GAB1 is also a functional caspase target by evidencing a caspase-cleaved p35-GAB1 fragment that contains the MET binding domain. GAB1 is cleaved by caspases before MET, and the resulting p35-GAB1 fragment is phosphorylated by MET upon HGF/SF binding and can interact with a subset of GAB1 partners, PI3K, and GRB2 but not with SHP2. This p35-GAB1 fragment favors cell survival by maintaining HGF/SF-induced MET activation of AKT and by hindering p40-MET pro-apoptotic function. These data demonstrate an anti-apoptotic role of caspase-cleaved GAB1 in HGF/SF-MET signaling.

Degradation of the GAB1 adaptor by the ubiquitin-proteasome pathway hampers HGF/SF-MET signaling.

The GRB2 associated binder 1 (GAB1) is an essential docking/adaptor protein for transmitting intracellular signals of the MET tyrosine kinase receptor activated by hepatocyte growth factor/scatter factor (HGF/SF). We found that in response to hours of HGF/SF treatment, the GAB1 protein level is degraded by a mechanism involving MET activity and the proteasomal machinery. We also showed that GAB1 is both multi- and poly-ubiquitinated in a CBL-dependent manner. A long term exposure to HGF/SF caused a more sustained down-regulation of GAB1 than of MET, associated with a loss of reactivation of the ERK MAP kinases to subsequent acute ligand treatment. These data demonstrate that GAB1 is ubiquitinated by CBL and degraded by the proteasome, and plays a role in negative-feedback regulation of HGF/SF-MET signaling.

Use of a Digital Cognitive Aid in the Early Management of Simulated War Wounds in a Combat Environment, a Randomized Trial.

INTRODUCTION: The French army has implemented an algorithm based on the acronym "MARCHE RYAN," each letter standing for a key action to complete in order to help first care providers during emergency casualty care. On the battlefield, the risk of error is increased, and the use of cognitive aids (CAs) might be helpful to avoid distraction. We investigated the effect of using a digital CA (MAX, for Medical Assistance eXpert) by combat casualty care providers on their technical and nontechnical performances during the early management of simulated war wounds, compared to their memory and training alone. MATERIALS AND METHODS: We conducted a randomized, controlled, unblinded study between July 2016 and February 2017. This study was approved by the Ethics Committee of the Ethical Board of Desgenettes Army Training Hospital (14.06.2017 n°385) and was registered on clinicaltrials.gov (NCT03483727). It took place during medicalization training in hostile environment ("MEDICHOS") in Chamonix Mont-Blanc and in the first aid training center in La Valbonne military base (France). Each participant had to deal with two different scenarios, one with MAX (MAX+) and the other without (MAX-). Scenarios were held using either high-fidelity patient simulators or actors as wounded patients. The primary outcome was participants' technical performance rated as their adherence to the MARCHE RYAN procedure (maximum 100%). The secondary outcome was the nontechnical performance according to the Ottawa crisis resource management Global Rating Scale (maximum 42). RESULTS: Technical performance was significantly higher in the MAX+ scenarios (70.60 IQR [63.70-73.56] than in the MAX- scenarios (56.25 IQR [52.88-62.09], p = 0.002). The Ottawa scores were significantly higher in the MAX+ scenarios (31.50 IQR [29.50-33.75]) than in the MAX- scenarios (29.50 IQR [24.50-32.00], p = 0.031). CONCLUSIONS: The use of a digital CA by combat casualty care providers improved technical and nontechnical performances during field training of simulated crises. Following recommendations on the design and use of CA, regular team training would improve fluidity in the use and acceptance of an aid, by a highly drilled professional corporation with a strong culture of leadership. Digital CA should be tested at a larger scale in order to validate their contribution to real combat casualty care.

Terrorist threat: Creating a nationwide damage control training program for non-trauma care providers.

INTRODUCTION: The current terrorist threat challenges nations to train numerous non-trauma care providers with different backgrounds in damage control (DC) strategies. The purpose of this work was to propose a specific DC training program. METHODS: A Task Force of 16 civilian and military physicians met for a 24-hour session, to propose the construction of a DC training program for non-specialised caregivers. RESULTS: Existing DC training programs are heterogeneous, mainly theoretical and almost only for physicians. A program entitled Damage Control for Terrorist Attack Victims (DC-TAV) was then proposed. Identified training targets were care providers from prehospital and hospital staffs, with no experience in trauma care. The training objectives were the improvement of individual and collective skills in managing terrorist attacks casualties. The tools selected for training concerned e-learning on a dedicated digital teaching platform (including a core section of four modules with types and mechanisms of injury, basic DC techniques, triage, organisation of emergency medical response and two complementary modules for doctors with DC resuscitation including remote transfusion and DC surgery), hands-on workshops with procedural simulation and full-scale simulation exercises, technical (tourniquets, haemostatic gauzes, needle thoracostomy, chest tube drainage, management of airway, coniotomy) and non-technical (leadership, communication, coordination and triage, decision-making, appropriate use of resources) skills. Finally, an evaluation of the DC-TAV program was planned. CONCLUSIONS: The DC-TAV program is an ambitious, civilian-military, nationwide and long-term program, based on a harmonised standard of care and including multidimensional training. Further studies are required to assess its efficacy.

Discovery of Human-Similar Gene Fusions in Canine Cancers.

Canine cancers represent a tremendous natural resource due to their incidence and striking similarities to human cancers, sharing similar clinical and pathologic features as well as oncogenic events, including identical somatic mutations. Considering the importance of gene fusions as driver alterations, we explored their relevance in canine cancers. We focused on three distinct human-comparable canine cancers representing different tissues and embryonic origins. Through RNA-Seq, we discovered similar gene fusions as those found in their human counterparts: IGK-CCND3 in B-cell lymphoma, MPB-BRAF in glioma, and COL3A1-PDGFB in dermatofibrosarcoma protuberans-like. We showed not only similar partner genes but also identical breakpoints leading to oncogene overexpression. This study demonstrates similar gene fusion partners and mechanisms in human-dog corresponding tumors and allows for selection of targeted therapies in preclinical and clinical trials with pet dogs prior to human trials, within the framework of personalized medicine. Cancer Res; 77(21); 5721-7. ©2017 AACR.

LMP1-induced cell death may contribute to the emergency of its oncogenic property.

BACKGROUND AND OBJECTIVES: Epstein-Barr Virus (EBV) Latent Membrane Protein 1 (LMP1) is linked to a variety of malignancies including Hodgkin's disease, lymphomas, nasopharyngeal and gastric carcinoma. LMP1 exerts its transforming or oncogenic activity mainly through the recruitment of intracellular adapters via LMP1 C-terminal Transformation Effector Sites (TES) 1 and 2. However, LMP1 is also reported to elicit significant cytotoxic effects in some other cell types. This cytotoxic effect is quite intriguing for an oncogenic protein, and it is unclear whether both functional aspects of the protein are related or mutually exclusive. METHODOLOGY AND PRINCIPAL FINDINGS: Using different ectopic expression systems in both Madin-Darby canine kidney (MDCK) epithelial cells and human embryonic kidney HEK-293 cells, we observe that LMP1 ectopic expression massively induces cell death. Furthermore, we show that LMP1-induced cytotoxicity mainly implies LMP1 C-terminal transformation effector sites and TRADD recruitment. However, stable expression of LMP1 in the same cells, is found to be associated with an increase of cell survival and an acquisition of epithelial mesenchymal transition phenotype as evidenced by morphological modifications, increased cell mobility, increased expression of MMP9 and decreased expression of E-cadherin. Our results demonstrate for the first time that the cytotoxic and oncogenic effects of LMP1 are not mutually exclusive but may operate sequentially. We suggest that in a total cell population, cells resistant to LMP1-induced cytotoxicity are those that could take advantage of LMP1 oncogenic activity by integrating LMP1 signaling into the pre-existent signaling network. Our findings thus reconcile the apparent opposite apoptotic and oncogenic effects described for LMP1 and might reflect what actually happens on LMP1-induced cell transformation after EBV infection in patients.