Pour une démocratie socio-environnementale : cadre pour une plate-forme participative « transition écologique »

Contribution publiée in Penser une démocratie alimentaire Volume II – Proposition Lascaux entre ressources naturelles et besoins fondamentaux, F. Collart Dutilleul et T. Bréger (dir), Inida, San José, 2014, pp. 87-111.International audienceL’anthropocène triomphant actuel, avec ses forçages environnementaux et sociaux, est à l’origine de l’accélération des dégradations des milieux de vie sur Terre et de l’accentuation des tensions sociales et géopolitiques. Passer à un anthropocène de gestion équitable, informé et sobre vis-à-vis de toutes les ressources et dans tous les secteurs d’activité (slow anthropocene), impose une analyse préalable sur l’ensemble des activités et des rapports humains. Cette transition dite « écologique », mais en réalité à la fois sociétale et écologique, est tout sauf un ajustement technique de secteurs dits prioritaires et technocratiques. Elle est avant tout culturelle, politique et philosophique au sens propre du terme. Elle est un horizon pour des trajectoires de développement humain, pour des constructions sociales et économiques, censées redéfinir socialement richesse, bien-être, travail etc. La dénomination « transition écologique » est largement véhiculée, mais ses bases conceptuelles ne sont pas entièrement acquises ni même élaborées. Dans ce contexte, les étudiants en première année de Master BioSciences à l’Ecole Normale Supérieure (ENS) de Lyon ont préparé une première étude analytique de ce changement radical et global de société pour mieux comprendre dans quelle société ils souhaitent vivre, en donnant du sens aux activités humaines présentes et à venir. Une trentaine de dossiers sur divers secteurs d’activités et acteurs de la société ont été produits et ont servis de support à cette synthèse. Plus largement, le but est de construire un socle conceptuel et une plate-forme de travail sur lesquels les questions de fond, mais aussi opérationnelles, peuvent être posées et étudiées en permanence. Cette démarche participative est ouverte à la collectivité sur le site http://institutmichelserres.ens-lyon.fr/

Effect of TGF beta produced by the microenvironment in exocrine pancreatic tumor

L’adénocarcinome du pancréas (ADKP) est une tumeur très agressive avec une médiane de survie de 9 mois, en raison de son diagnostic tardif et de sa résistance aux traitements. Il se caractérise par un stroma abondant, composant jusqu’à 90% de la masse tumorale. Dans ce stroma on trouve différents types de cellules (e.g. fibroblastes, cellules immunitaires) qui vont sécréter différents facteurs et notamment du TGFβ1 (Transforming Growth Factor beta) qui a un rôle à la fois pro et anti oncogéniques. Il agit sur les cellules tumorales, sur les différents types cellulaires du microenvironnement et même au-delà. Des quantités importantes de TGFβ1 sont retrouvées dans le sang des patients atteints d’ADKP et vont participer à l’invasion tumorale, l’établissement de métastases mais également, avec d’autres cytokines, à la mise en place de la cachexie. 80 % des patients atteints d’ADKP sont atteints de cachexie au moment du diagnostic ou le deviennent. Ce syndrome paranéoplasique se caractérise par une diminution des masses musculaires et adipeuses. Il affecte de façon considérable la qualité de vie des patients, augmente leur résistance aux traitements et constitue donc un enjeu clinique majeur. Mon projet de thèse vise donc à mieux comprendre le rôle du TGFβ1 (i) dans les interactions qui s’établissent entre le stroma et les cellules cancéreuses, (ii) dans les interactions entre la tumeur et le tissu musculaire. Pour répondre à cette question, nous avons généré deux nouveaux allèles nous permettant d’exprimer du TGFβ bioactif par les fibroblastes dans un nouveau modèle murin ([Fsp1-Flpo ; FSFTGFβCA]). Ce dernier nous permettra d’étudier le rôle du TGFβ1 dans le compartiment fibroblastique. Grâce à ce modèle murin Flpo/frt, nous avons pu créer un nouveau DRS (Double Recombinase System) permettant d’étudier l’effet du TGFβ1 produit par les fibroblastes dans le micro-environnement tumorale, au cours de l’ADKP. En effet, nous l’avons croisé avec un modèle Cre/lox développant des lésions épithéliales pancréatiques induites par l’oncogène Kras activé (KrasG12D) (Kirsten rat sarcoma) (Hingorani et al. 2003), associant les systèmes Cre/Lox et Flpo/Frt au sein du même animal. Nous avons validé ce nouveau DRS [Fsp1-Flpo ; FSFTGFβCA ; Pdx1-Cre ; LSLKrasG12D] et commencé à le caractériser. Nous n’avons pas mis en évidence de différences significatives au niveau des lésions pancréatiques avant 6 mois, mais nous avons détecté des métastases dans toutes les souris à des stades plus tardifs et une perte de poids progressive témoignant d’un état de cachexie. Afin de mieux comprendre les effets cachectiques observés dans ce DRS, nous l’avons comparé avec un autre modèle de cachexie induite par l’ADKP : le modèle murin KPC. Afin de déterminer les événements moléculaires précoces induits par la tumeur et menant à cette cachexie, et déterminer en quoi le TGFβ1 pourrait être impliqué, nous avons analysé le muscle de ces souris avant le début de leur perte de poids. Nous avons observé la mise en place progressive de plusieurs processus biologiques et notamment l’activation de la voie du TGFβ. Nous avons donc voulu voir l’impact d’une activation constitutive de la voie de signalisation du TGFβ dans le muscle. Pour cela nous avons construit un modèle murin exprimant de façon conditionnelle un récepteur au TGFβ (TβRI) constitutivement activé spécifiquement dans le muscle (modèle RCA). Nous avons pu observer la mise en place d’une atrophie musculaire induite par le TGFβ dans ces souris. Ce modèle RCA montre le lien entre TGFβ et atrophie musculaire et constitue un bon modèle d’étude de l’atrophie musculaire. Au cours de ma thèse j’ai donc développé un modèle permettant de mieux comprendre les interactions stroma-cellules tumorales, de déterminer les mécanismes cellulaires à la base de la tumorigénèse pancréatique, mais également d’identifier les mécanismes moléculaires précoces d’atteinte musculaire et ceux spécifiquement induits par le TGFβThe pancreatic ductal adenocarcinoma (PDAC) is a very aggressive tumor with a median survival lower than 6 months after diagnosis. This is due to the late diagnosis and the resistance to the treatment. The PDAC is characterized by an abundant desmoplastic stroma representing 90% of the total tumor volume. In this stroma we can find different types of cells. These cells secrete factors and among them the TGFβ (Transforming Growth Factor beta) which has both pro and anti-oncogenic functions. It has effects on tumor cell, different types of cells from the microenvironment and beyond the local microenvironment. Important amount of TGFβ are detected in blood from PDAC patients. This TGFβ will participate in tumor invasion, metastasis formation but also with other cytokines to the establishment of cachexia. 80% of patients have cachexia when they are diagnosed or develop it later. This paraneoplastic syndrome is characterized by a weight decrease of adipose and muscle tissue. It has an impact on patient quality of life (QoL). It is also responsible for treatment resistance and thus, it is a major clinical challenge. My PhD project aims at better understanding the TGFβ function in (i) local interactions between stromal and cancer cells, (ii) systemic interactions between the tumor and the muscle compartment. For that purpose, we generated two new alleles (Fsp1-Flpo and FSFTGFβCA). These two combined alleles lead to the expression of bioactive TGFβ through fibroblasts in a new mouse model ([Fsp1-Flpo; FSFTGFβCA]). This new mouse model will enable us to decipher the role of TGFβ1 in the fibroblast compartment. Using this new validated Flpo/frt-mouse model ([Fsp1-Flpo; FSFTGFβCA]), we were able to create a new DRS, to study the effects of TGFβ1 produced by the fibroblasts in the microenvironment during PDAC development. We combined this model with the Cre/lox model developing Kras-induced (KrasG12D) (Kirsten rat sarcoma) epithelial lesions in the pancreas (Hingorani et al. 2003). Thus, we associated Cre/lox and Flpo/frt systems in the same mouse. We validated this new DRS [Fsp1-Flpo; FSFTGFβCA; Pdx1-Cre; LSLKrasG12D] and started to characterize it. We didn’t observe statistical differences in term of pancreatic lesions before 6 months. However, we detected metastasis in all mice in later stages and noticed a progressive loss of weight in these mice after 8 months. Thus, [Fsp1-Flpo; FSFTGFβCA; Pdx1-Cre; LSLKrasG12D] mice seem to develop cachexia. In order to better understand the cachexic effects observed in DRS expressing TGFβ1 in a mutated Kras context, we compared it to another PDAC-induced cachexia model: the KPC mouse model. We aimed at understanding the early molecular events induced by the tumor and leading to cachexia. We also wanted to determine the TGFβ1 involvement in this process. For that purpose, we analyzed KPC mice muscle before they begin to lose weight. We observed the progressive establishment of different biological processes including TGFβ pathway activation. Thus, we wanted to see the impact of a constitutive TGFβ pathway activation in the muscle. To that end, we created a murine model conditionally (CreERT2) expressing a constitutively activated TGFβ specifically in the muscle (called RCA model). These mice developed severe TGFβ-induced muscle atrophy. This RCA mouse model establish the link between TGFβ and muscle atrophy and it is a good model to study muscle atrophy. During my PhD, I developed a model to better understand the stromal-tumoral cell interactions, the cell mechanisms at the origin of tumorigenesis, but also, to identify the early events leading to muscular atrophy and the part of TGFβ in this proces

Physical Activity as the Best Supportive Care in Cancer: The Clinician’s and the Researcher’s Perspectives

International audienceMultidisciplinary supportive care, integrating the dimensions of exercise alongside oncological treatments, is now regarded as a new paradigm to improve patient survival and quality of life. Its impact is important on the factors that control tumor development, such as the immune system, inflammation, tissue perfusion, hypoxia, insulin resistance, metabolism, glucocorticoid levels, and cachexia. An increasing amount of research has been published in the last years on the effects of physical activity within the framework of oncology, marking the appearance of a new medical field, commonly known as “exercise oncology”. This emerging research field is trying to determine the biological mechanisms by which, aerobic exercise affects the incidence of cancer, the progression and/or the appearance of metastases. We propose an overview of the current state of the art physical exercise interventions in the management of cancer patients, including a pragmatic perspective with tips for routine practice. We then develop the emerging mechanistic views about physical exercise and their potential clinical applications. Moving toward a more personalized, integrated, patient-centered, and multidisciplinary management, by trying to understand the different interactions between the cancer and the host, as well as the impact of the disease and the treatments on the different organs, this seems to be the most promising method to improve the care of cancer patients

The immunological landscape in pancreatic ductal adenocarcinoma and overcoming resistance to immunotherapy

International audiencePancreatic ductal adenocarcinoma is associated with a poor prognosis and there are few treatment options. The development of immunotherapy in pancreatic ductal adenocarcinoma has been difficult, and immune checkpoint inhibitors are only effective in a very small subset of patients. Most obstacles for treatment have been related to intertumoural and intratumoural heterogeneity, the composition of tumour stroma, and crosstalk with cancer cells. Improved molecular characterisation of pancreatic ductal adenocarcinoma and a better understanding of its microenvironment have paved the way for novel immunotherapy strategies, including the identification of predictive biomarkers, the development of rational combinations to optimise effectiveness, and the targeting of new mechanisms. Future immunotherapy strategies should consider individual characteristics to move beyond the traditional immune targets and circumvent the resistance to therapies that have been developed so far

pEVL: A Linear Plasmid for Generating mRNA IVT Templates With Extended Encoded Poly(A) Sequences

Increasing demand for large-scale synthesis of in vitro transcribed (IVT) mRNA is being driven by the increasing use of mRNA for transient gene expression in cell engineering and therapeutic applications. An important determinant of IVT mRNA potency is the 3′ polyadenosine (poly(A)) tail, the length of which correlates with translational efficiency. However, present methods for generation of IVT mRNA rely on templates derived from circular plasmids or PCR products, in which homopolymeric tracts are unstable, thus limiting encoded poly(A) tail lengths to ≃120 base pairs (bp). Here, we have developed a novel method for generation of extended poly(A) tracts using a previously described linear plasmid system, pJazz. We find that linear plasmids can successfully propagate poly(A) tracts up to ≃500 bp in length for IVT mRNA production. We then modified pJazz by removing extraneous restriction sites, adding a T7 promoter sequence upstream from an extended multiple cloning site, and adding a unique type-IIS restriction site downstream from the encoded poly(A) tract to facilitate generation of IVT mRNA with precisely defined encoded poly(A) tracts and 3′ termini. The resulting plasmid, designated pEVL, can be used to generate IVT mRNA with consistent defined lengths and terminal residue(s)

Generation of a conditional Flpo/FRT mouse model expressing constitutively active TGFβ in fibroblasts

International audienceTransforming growth factor (TGFβ) is a secreted factor, which accumulates in tissues during many physio- and pathological processes such as embryonic development, wound healing, fibrosis and cancer. In order to analyze the effects of increased microenvironmental TGFβ concentration in vivo, we developed a conditional transgenic mouse model (Flpo/Frt system) expressing bioactive TGFβ in fibroblasts, a cell population present in the microenvironment of almost all tissues. To achieve this, we created the genetically-engineered [Fsp1-Flpo; FSFTGFβCA] mouse model. The Fsp1-Flpo allele consists in the Flpo recombinase under the control of the Fsp1 (fibroblast-specific promoter 1) promoter. The FSFTGFβCA allele consists in a transgene encoding a constitutively active mutant form of TGFβ (TGFβCA) under the control of a Frt-STOP-Frt (FSF) cassette. The FSFTGFβCA allele was created to generate this model, and functionally validated by in vitro, ex vivo and in vivo techniques. [Fsp1-Flpo; FSFTGFβCA] animals do not present any obvious phenotype despite the correct expression of TGFβCA transgene in fibroblasts. This [Fsp1-Flpo; FSFTGFβCA] model is highly pertinent for future studies on the effect of increased microenvironmental bioactive TGFβ concentrations in mice bearing Cre-dependent genetic alterations in other compartments (epithelial or immune compartments for instance). These dual recombinase system (DRS) approaches will enable scientists to study uncoupled spatiotemporal regulation of different genetic alterations within the same mouse, thus better replicating the complexity of human diseases

Hypothalamic–pituitary–adrenal axis activation and glucocorticoid-responsive gene expression in skeletal muscle and liver of Apc mice

International audienceBackground: Cancer patients at advanced stages experience a severe depletion of skeletal muscle compartment together with a decrease in muscle function, known as cancer cachexia. Cachexia contributes to reducing quality of life, treatment efficiency, and lifespan of cancer patients. However, the systemic nature of the syndrome is poorly documented. Here, we hypothesize that glucocorticoids would be important systemic mediators of cancer cachexia. Methods: To explore the role of glucocorticoids during cancer cachexia, biomolecular analyses were performed on several tissues (adrenal glands, blood, hypothalamus, liver, and skeletal muscle) collected from Apc Min/+ male mice, a mouse model of intestine and colon cancer, aged of 13 and 23 weeks, and compared with wild type age-matched C57BL/6J littermates. Results: Twenty-three-week-old Apc mice recapitulated important features of cancer cachexia including body weight loss (À16%, P < 0.0001), muscle atrophy (gastrocnemius muscle: À53%, P < 0.0001), and weakness (À50% in tibialis anterior muscle force, P < 0.0001), increased expression of atrogens (7-fold increase in MuRF1 transcript level, P < 0.0001) and down-regulation of Akt-mTOR pathway (3.3-fold increase in 4EBP1 protein content, P < 0.0001), together with a marked transcriptional rewiring of hepatic metabolism toward an increased expression of gluconeogenic genes (Pcx

Multicenter randomized controlled trial of neoadjuvant chemoradiotherapy alone or in combination with pembrolizumab in patients with resectable or borderline resectable pancreatic adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a challenging target for immunotherapy because it has an immunosuppressive tumor microenvironment. Neoadjuvant chemoradiotherapy can increase tumor-infiltrating lymphocyte (TIL) density, which may predict overall survival (OS). We hypothesized that adding programmed cell death protein 1 (PD-1) blockade to chemoradiotherapy would be well tolerated and increase TILs among patients with localized PDAC.MethodsPatients were randomized 2:1 to Arm A (receiving pembrolizumab plus chemoradiotherapy (capecitabine and external beam radiation)) or Arm B (receiving chemoradiotherapy alone) before anticipated pancreatectomy. Primary endpoints were (1) incidence and severity of adverse events during neoadjuvant therapy and (2) density of TILs in resected tumor specimens. TIL density was assessed using multiplexed immunofluorescence histologic examination.ResultsThirty-seven patients were randomized to Arms A (n=24) and B (n=13). Grade ≥3 adverse events related to neoadjuvant treatment were experienced by 9 (38%) and 4 (31%) patients in Arms A and B, respectively, with one patient experiencing dose-limiting toxicity in Arm A. Seventeen (71%) and 7 (54%) patients in Arms A and B, respectively, underwent pancreatectomy. Median CD8+ T-cell densities in Arms A and B were 67.4 (IQR: 39.2–141.8) and 37.9 (IQR: 22.9–173.4) cells/mm2, respectively. Arms showed no noticeable differences in density of CD8+Ki67+, CD4+, or CD4+FOXP3+ regulatory T cells; M1-like and M2-like macrophages; or granulocytes. Median OS durations were 27.8 (95% CI: 17.1 to NR) and 24.3 (95% CI: 12.6 to NR) months for Arms A and B, respectively.ConclusionsAdding pembrolizumab to neoadjuvant chemoradiotherapy was safe. However, no convincing effect on CD8+ TILs was observed

SMAD2/3 mediate oncogenic effects of TGF-β in the absence of SMAD4

International audienceTGF-β signaling is involved in pancreatic ductal adenocarcinoma (PDAC) tumorigenesis, representing one of the four major pathways genetically altered in 100% of PDAC cases. TGF-β exerts complex and pleiotropic effects in cancers, notably via the activation of SMAD pathways, predominantly SMAD2/3/4. Though SMAD2 and 3 are rarely mutated in cancers, SMAD4 is lost in about 50% of PDAC, and the role of SMAD2/3 in a SMAD4-null context remains understudied. We herein provide evidence of a SMAD2/3 oncogenic effect in response to TGF-β1 in SMAD4-null human PDAC cancer cells. We report that inactivation of SMAD2/3 in SMAD4-negative PDAC cells compromises TGF-β-driven collective migration mediated by FAK and Rho/Rac signaling. Moreover, RNA-sequencing analyses highlight a TGF-β gene signature related to aggressiveness mediated by SMAD2/3 in the absence of SMAD4. Using a PDAC patient cohort, we reveal that SMAD4-negative tumors with high levels of phospho-SMAD2 are more aggressive and have a poorer prognosis. Thus, loss of SMAD4 tumor suppressive activity in PDAC leads to an oncogenic gain-of-function of SMAD2/3, and to the onset of associated deleterious effects

Schwann cells support oncogenic potential of pancreatic cancer cells through TGFβ signaling

International audiencePancreatic ductal adenocarcinoma (PDAC) is one of the solid tumors with the poorest prognosis. The stroma of this tumor is abundant and composed of extracellular matrix and stromal cells (including cancer-associated fibroblasts and immune cells). Nerve fibers invading this stroma represent a hallmark of PDAC, involved in neural remodeling, which participates in neuropathic pain, cancer cell dissemination and tumor relapse after surgery. Pancreatic cancer-associated neural remodeling is regulated through functional interplays mediated by physical and molecular interactions between cancer cells, nerve cells and surrounding Schwann cells, and other stromal cells. In the present study, we show that Schwann cells (glial cells supporting peripheral neurons) can enhance aggressiveness (migration, invasion, tumorigenicity) of pancreatic cancer cells in a transforming growth factor beta (TGFβ)-dependent manner. Indeed, we reveal that conditioned medium from Schwann cells contains high amounts of TGFβ able to activate the TGFβ-SMAD signaling pathway in cancer cells. We also observed in human PDAC samples that high levels of TGFβ signaling activation were positively correlated with perineural invasion. Secretome analyses by mass spectrometry of Schwann cells and pancreatic cancer cells cultured alone or in combination highlighted the central role of TGFβ in neuro-epithelial interactions, as illustrated by proteomic signatures related to cell adhesion and motility. Altogether, these results demonstrate that Schwann cells are a meaningful source of TGFβ in PDAC, which plays a crucial role in the acquisition of aggressive properties by pancreatic cancer cells