52 research outputs found
Liver carcinogenesis by FOS-dependent inflammation and cholesterol dysregulation
233294Human hepatocellular carcinomas (HCCs), which arise on a background of chronic liver damage and inflammation, express c-Fos, a component of the AP-1 transcription factor. Using mouse models, we show that hepatocyte-specific deletion of c-Fos protects against diethylnitrosamine (DEN)-induced HCCs, whereas liver-specific c-Fos expression leads to reversible premalignant hepatocyte transformation and enhanced DEN-carcinogenesis. c-Fos-expressing livers display necrotic foci, immune cell infiltration, and altered hepatocyte morphology. Furthermore, increased proliferation, dedifferentiation, activation of the DNA damage response, and gene signatures of aggressive HCCs are observed. Mechanistically, c-Fos decreases expression and activity of the nuclear receptor LXRα, leading to increased hepatic cholesterol and accumulation of toxic oxysterols and bile acids. The phenotypic consequences of c-Fos expression are partially ameliorated by the anti-inflammatory drug sulindac and largely prevented by statin treatment. An inverse correlation between c-FOS and the LXRα pathway was also observed in human HCC cell lines and datasets. These findings provide a novel link between chronic inflammation and metabolic pathways important in liver cancer.We thank Drs. N. Djouder, M. Petruzzelli, R. Ricci, F.X Real, K.D. Bissig, and members of
the Wagner laboratory for critical reading of the manuscript and valuable sugges-
tions; Dr. H. Schönthaler for help with the bioinformatics analysis; V. Bermeo for
technical help; and G. Luque, S. Leceta, and G. Medrano for assisting with
mouse experiments.
The E.F. Wagner laboratory is supported by grants from the Spanish Ministry of
Economy, Industry, and Competitiveness (BFU2012-40230 and SAF2015-70857, co-
funded by the European Regional Development Fund), a European Research Councilâ
advanced grant (ERC-FCK/2008/37), and Worldwide Cancer Research (13-0216).
R. Hamacher was supported by the Deutsche Forschungsgemeinschaft (HA 6068/1-1),
M.K. Thomsen by AUFF Nova, and S.C. Hasenfuss by a Boehringer Ingelheim Fonds
PhD fellowship.
The authors declare no competing financial interests.
Author contributions: L. Bakiri and R. Hamacher designed and performed exper-
iments, analyzed data, prepared figures, and wrote the manuscript. O. Graña analyzed
RNA-seq and public microarray data, A. GuĂo-CarriĂłn provided expert technical assis-
tance, R. Campos-Olivas acquired and analyzed NMR data, L. Martinez analyzed flow
cytometry data, M.K. Thomsen performed experiments with human cell lines, S.C.
Hasenfuss performed experiments with primary hepatocytes and data mining, and
H.P. Dienes performed pathological analysis on tissue sections. E.F. Wagner directed
the study, approved the data, and wrote and edited the paper. All authors read and
commented on the manuscript.S
Wnt signaling and Loxl2 promote aggressive osteosarcoma
Osteosarcoma (OS) is the most frequent primary malignant bone tumor in urgent need of better therapies. Using genetically
modified mouse models (GEMMs), we demonstrate that Wnt signaling promotes c-Fos-induced OS formation via the actions of the
collagen-modifying enzyme Loxl2. c-Fos/AP-1 directly regulates the expression of the Wnt ligands Wnt7b and Wnt9a in OS cells
through promoter binding, and Wnt7b and Wnt9a in turn promote Loxl2 expression in murine and human OS cells through the
transcription factors Zeb1 and Zeb2. Concordantly, inhibition of Wnt ligand secretion by inactivating the Wnt-less (Wls) gene in
osteoblasts in c-Fos GEMMs either early or in a therapeutic setting reduces Loxl2 expression and progression of OS. Wls-deficient
osteosarcomas proliferate less, are less mineralized and are enriched in fibroblastic cells surrounded by collagen fibers. Importantly,
Loxl2 inhibition using either the pan-Lox inhibitor BAPN or a specific inducible shRNA reduces OS cell proliferation in vitro and
decreases tumor growth and lung colonization in murine and human orthotopic OS transplantation models. Finally, OS
development is delayed in c-Fos GEMMs treated with BAPN or with specific Loxl2 blocking antibodies. Congruently, a strong
correlation between c-FOS, LOXL2 and WNT7B/WNT9A expression is observed in human OS samples, and c-FOS/LOXL2 coexpression correlates with OS aggressiveness and decreased patient survival. Therefore, therapeutic targeting of Wnt and/or
Loxl2 should be considered to potentiate the inadequate current treatments for pediatric, recurrent, and metastatic OS
Keratinocyte-derived S100A9 modulates neutrophil infiltration and affects psoriasis-like skin and joint disease
[Objectives]: S100A9, an alarmin that can form calprotectin (CP) heterodimers with S100A8, is mainly produced by keratinocytes and innate immune cells. The contribution of keratinocyte-derived S100A9 to psoriasis (Ps) and psoriatic arthritis (PsA) was evaluated using mouse models, and the potential usefulness of S100A9 as a Ps/PsA biomarker was assessed in patient samples.
[Methods]: Conditional S100A9 mice were crossed with DKO* mice, an established psoriasis-like mouse model based on inducible epidermal deletion of c-Jun and JunB to achieve additional epidermal deletion of S100A9 (TKO* mice). Psoriatic skin and joint disease were evaluated in DKO* and TKO* by histology, microCT, RNA and proteomic analyses. Furthermore, S100A9 expression was analysed in skin, serum and synovial fluid samples of patients with Ps and PsA.
[Results]: Compared with DKO* littermates, TKO* mice displayed enhanced skin disease severity, PsA incidence and neutrophil infiltration. Altered epidermal expression of selective pro-inflammatory genes and pathways, increased epidermal phosphorylation of STAT3 and higher circulating TNFα were observed in TKO* mice. In humans, synovial S100A9 levels were higher than the respective serum levels. Importantly, patients with PsA had significantly higher serum concentrations of S100A9, CP, VEGF, IL-6 and TNFα compared with patients with only Ps, but only S100A9 and CP could efficiently discriminate healthy individuals, patients with Ps and patients with PsA.
[Conclusions]: Keratinocyte-derived S100A9 plays a regulatory role in psoriatic skin and joint disease. In humans, S100A9/CP is a promising marker that could help in identifying patients with Ps at risk of developing PsA.The Wagner laboratory at the Medical University of Vienna (MUV) is supported by an ERCâAdG 2016 CSIâFunâ741888, a H2020âMSCAâITN 2019â859860âCANCERPREV grant and the MUV. GS and AR are supported by the Deutsche Forschungsgemeinschaft (DFG-FOR2886 PANDORA and the CRC1181 Checkpoints for Resolution of Inflammation). Additional funding was received by the Bundesministerium fĂŒr Bildung und Forschung (BMBF; project MASCARA), the ERC-SyG 2018 (810316 4D Nanoscope), ERC-STG 2019 (853508 BARRIER BREAK) and the IMI-funded project Hippocrates. The Oxford Laboratory at the Biomolecular Research Centre at Boise State University was supported by the National Institutes of Health, NIGMS P20GM109095 and P20GM103408
Interleukinâ6 initiates muscleâ and adipose tissue wasting in a novel C57BL/6 model of cancerâassociated cachexia
BACKGROUND: Cancerâassociated cachexia (CAC) is a wasting syndrome drastically reducing efficacy of chemotherapy and life expectancy of patients. CAC affects up to 80% of cancer patients, yet the mechanisms underlying the disease are not well understood and no approved diseaseâspecific medication exists. As a multiorgan disorder, CAC can only be studied on an organismal level. To cover the diverse aetiologies of CAC, researchers rely on the availability of a multifaceted pool of cancer models with varying degrees of cachexia symptoms. So far, no tumour model syngeneic to C57BL/6 mice exists that allows direct comparison between cachexigenicâ and nonâcachexigenic tumours. METHODS: MCA207 and CHX207 fibrosarcoma cells were intramuscularly implanted into male or female, 10â11âweekâold C57BL/6J mice. Tumour tissues were subjected to magnetic resonance imaging, immunohistochemicalâ, and transcriptomic analysis. Mice were analysed for tumour growth, body weight and âcomposition, foodâ and water intake, locomotor activity, O(2) consumption, CO(2) production, circulating blood cells, metabolites, and tumourkines. Mice were sacrificed with same tumour weights in all groups. Adipose tissues were examined using highâresolution respirometry, lipolysis measurements in vitro and ex vivo, and radioactive tracer studies in vivo. Gene expression was determined in adiposeâ and muscle tissues by quantitative PCR and Western blotting analyses. Muscles and cultured myotubes were analysed histologically and by immunofluorescence microscopy for myofibre cross sectional area and myofibre diameter, respectively. Interleukinâ6 (Ilâ6) was deleted from cancer cells using CRISPR/Cas9 mediated gene editing. RESULTS: CHX207, but not MCA207âtumourâbearing mice exhibited major clinical features of CAC, including systemic inflammation, increased plasma ILâ6 concentrations (190 pg/mL, P â€Â 0.0001), increased energy expenditure (+28%, P â€Â 0.01), adipose tissue loss (â47%, P â€Â 0.0001), skeletal muscle wasting (â18%, P â€Â 0.001), and body weight reduction (â13%, P â€Â 0.01) 13 days after cancer cell inoculation. Adipose tissue loss resulted from reduced lipid uptake and âsynthesis combined with increased lipolysis but was not associated with elevated betaâadrenergic signalling or adipose tissue browning. Muscle atrophy was evident by reduced myofibre cross sectional area (â21.8%, P â€Â 0.001), increased catabolicâ and reduced anabolic signalling. Deletion of ILâ6 from CHX207 cancer cells completely protected CHX207(IL6KO)âtumourâbearing mice from CAC. CONCLUSIONS: In this study, we present CHX207 fibrosarcoma cells as a novel tool to investigate the mediators and metabolic consequences of CAC in C57BL/6 mice in comparison to nonâcachectic MCA207âtumourâbearing mice. ILâ6 represents an essential trigger for CAC development in CHX207âtumourâbearing mice
Pharmacologic activation of LXR alters the expression profile of tumor-associated macrophages and the abundance of regulatory T cells in the tumor microenvironment
Liver X receptors (LXR) are transcription factors from the nuclear receptor family that are activated by oxysterols and synthetic high-affinity agonists. In this study, we assessed the antitumor effects of synthetic LXR agonist TO901317 in a murine model of syngeneic Lewis Lung carcinoma. Treatment with TO901317 inhibited tumor growth in wild-type, but not in LXR-deficient mice, indicating that the antitumor effects of the agonist depends on functional LXR activity in host cells. Pharmacologic activation of the LXR pathway reduced the intratumoral abundance of regulatory T cells (Treg) and the expression of the Treg-attracting chemokine Ccl17 by MHCIIhigh tumor-associated macrophages (TAM). Moreover, gene expression profiling indicated a broad negative impact of the LXR agonist on other mechanisms used by TAM for the maintenance of an immunosuppressive environment. In studies exploring the macrophage response to GM-CSF or IL4, activated LXR repressed IRF4 expression, resulting in subsequent downregulation of IRF4-dependent genes including Ccl17. Taken together, this work reveals the combined actions of the LXR pathway in the control of TAM responses that contribute to the antitumoral effects of pharmacologic LXR activation. Moreover, these data provide new insights for the development of novel therapeutic options for the treatment of cancer.This work was supported by the following grants: Spanish Ministry of Economy and Competitivity (MINECO) grants SAF2017-89510-R and SAF2014-57856-P [to A.F. Valledor and C. Caelles; SAF2014-56819-R to A. Castrillo; SAF2017-90604-REDT and SAF2015-71878-REDT to the NuRCaMeIn network (to A.F. Valledor, C. Caelles, and A. Castrillo); Spanish Ministry of Science and Innovation (MICINN) grants SAF2011-23402 and SAF2010-14989 (to A.F. Valledor); Fundacio La Marato de TV3 grant 080930 (to A.F. Valledor); grants DFG HU 1824/5-1, 1824/7-1, and 1824/9-1 (to M. Huber); the European Cooperation in Science and Technology (COST) Action BM1404 Mye-EUNITER (http://www.mye-euniter. eu/; to A.F. Valledor, J.A. Van Ginderachter); and Instituto de Salud Carlos III and FEDER âUna manera de hacer Europaâ grant FIS 16/00139 (to J.C. Escola-Gil). CIBERDEM is an Instituto de Salud Carlos III project. J.M. C received a fellowship from the University of Barcelona (APIF) and J. Font-DĂaz received a fellowship
from the Spanish Ministry of Science, Innovation and Universities (FPI, PRE2018-085579)
Pharmacological activation of LXR alters the expression profile of tumor-associated macrophages and the abundance of regulatory T cells in the tumor microenvironment
Liver X receptors (LXR) are transcription factors from the nuclear receptor family that are activated by oxysterols and synthetic high-affinity agonists. In this study, we assessed the anti-tumor effects of synthetic LXR agonist TO901317 in a murine model of syngeneic Lewis Lung carcinoma. Treatment with TO901317 inhibited tumor growth in wild-type but not in LXR-deficient mice, indicating that the anti-tumor effects of the agonist depends on functional LXR activity in host cells. Pharmacological activation of the LXR pathway reduced the intratumoral abundance of regulatory T cells (Treg) and the expression of the Treg-attracting chemokine Ccl17 by MHCIIhigh tumor-associated macrophages (TAM). Moreover, gene expression profiling indicated a broad negative impact of the LXR agonist on other mechanisms used by TAM for the maintenance of an immunosuppressive environment. In studies exploring the macrophage response to GM-CSF or IL-4, activated LXR repressed IRF4 expression, resulting in subsequent downregulation of IRF4-dependent genes including Ccl17. Taken together, this work reveals the combined actions of the LXR pathway in the control of TAM responses that contribute to the anti-tumoral effects of pharmacological LXR activation. Moreover, these data provide new insights for the development of novel therapeutic options for the treatment of cancer
JunB Inhibits ER Stress and Apoptosis in Pancreatic Beta Cells
Cytokines contribute to pancreatic ÎČ-cell apoptosis in type 1 diabetes (T1D) by modulation of ÎČ-cell gene expression networks. The transcription factor Activator Protein-1 (AP-1) is a key regulator of inflammation and apoptosis. We presently evaluated the function of the AP-1 subunit JunB in cytokine-mediated ÎČ-cell dysfunction and death. The cytokines IL-1ÎČ+IFN-Îł induced an early and transitory upregulation of JunB by NF-ÎșB activation. Knockdown of JunB by RNA interference increased cytokine-mediated expression of inducible nitric oxide synthase (iNOS) and endoplasmic reticulum (ER) stress markers, leading to increased apoptosis in an insulin-producing cell line (INS-1E) and in purified rat primary ÎČ-cells. JunB knockdown ÎČ-cells and junBâ/â fibroblasts were also more sensitive to the chemical ER stressor cyclopiazonic acid (CPA). Conversely, adenoviral-mediated overexpression of JunB diminished iNOS and ER markers expression and protected ÎČ-cells from cytokine-induced cell death. These findings demonstrate a novel and unexpected role for JunB as a regulator of defense mechanisms against cytokine- and ER stress-mediated apoptosis
Fra-1 promotes growth and survival in RAS-transformed thyroid cells by controlling cyclin A transcription
ETUDE DU ROLE DES PROTEINES C-JUN ET JUNB ET DU FACTEUR DE TRANSCRIPTION AP-1 DANS LA DIVISION CELLULAIRE
C-JUN ET JUNB SONT DES MEMBRES DE LA SUPERFAMILLE DES PROTEINES A BZIP QUI PARTICIPENT A LA FORMATION DU FACTEUR DE TRANSCRIPTION AP-1. NOUS AVONS CONSTRUIT DES ALLELES INDUCTIBLES DE C-JUN ET JUNB EN LES FUSIONNANT AVEC LE DOMAINE LIANT L'HORMONE DU RECEPTEUR A L'STRADIOL. EN UTILISANT CES ALLELES, NOUS AVONS CONSTATE QUE L'ACTIVATION DE C-JUN MET EN ROUTE UN PROGRAMME DE MORT CELLULAIRE DANS LES FIBROBLASTES NIH3T3. L'APOPTOSE EST DEPENDANTE DE L'ACTIVITE TRANSCRIPTIONNELLE DE C-JUN, EST MODULEE PAR BCL-2 ET LES PROTEASES ICE ET S'ACCOMPAGNE D'UNE INDUCTION DE LA TRANSGLUTAMINASE. A L'INVERSE, L'ACTIVATION DE JUNE N'ALTERE PAS LA VIABILITE CELLULAIRE MAIS PROVOQUE UNE ACCUMULATION DES CELLULES DANS LA PHASE G1 DU CYCLE CELLULAIRE, PRINCIPALEMENT MEDIEE PAR UNE REPRESSION TRANSCRIPTIONNELLE D'UN EFFECTEUR CLE DE LA TRANSITION G1/S : LA CYCLINE D1. NOUS AVONS ANALYSE LES VARIATIONS QUALITATIVES ET QUANTITATIVES DE C-JUN ET JUNB DANS LES CELLULES CYCLANTES. LA PHOSPHORYLATION DE RESIDUS SPECIFIQUES DE JUNB PAR LA KINASE MITOTIQUE CDC-2/CYCLINEB EST ASSOCIEE AVEC UNE DIMINUTION DE LA PROTEINE EN MITOSE ET AU DEBUT DE G1. A L'OPPOSE, C-JUN NE VARIE PAS MAIS SUBIT UNE PHOSPHORYLATION N-TERMINALE QUI AUGMENTE SON POUVOIR TRANSACTIVATEUR. DANS LA MESURE OU JUNB REPRIME TANDIS QUE C-JUN ACTIVE LA TRANSCRIPTION DE LA CYCLINE D1, CETTE MODIFICATION DU RAPPORT C-JUN/JUNB POURRAIT ETRE UN SIGNAL POSITIF DE PROGRESSION VERS LA PHASE S ET CONSTITUERAIT UN NOUVEL EXEMPLE DE CONNEXION RECIPROQUE ENTRE LA MACHINERIE DU CYCLE CELLULAIRE ET LES FACTEURS DE TRANSCRIPTION. AP-1 EST CONSTITUE D'UNE COLLECTION DE DIMERES ENTRE LES PROTEINES JUN, FOS ET LES PROTEINES BZIP APPARENTEES. LA FORMATION DE CHAQUE COMPLEXE DEPEND STRICTEMENT DES AFFINITES DE DIMERISATION ET DE L'ABONDANCE RELATIVE DES MONOMERES QUI LE COMPOSENT. CHAQUE DIMERE EST FONCTIONNELLEMENT UNIQUE SI ON CONSIDERE SES GENES CIBLES ET SON POUVOIR TRANSACTIVATEUR. POUR PROGRESSER DANS L'IDENTIFICATION DES FONCTIONS DES COMPLEXES AP-1 INDIVIDUELS, NOUS AVONS CONCU DES POLY-PROTEINES DE FUSION DANS LESQUELLES DEUX MONOMERES JUN ET FOS SONT LIES PAR UN POLYPEPTIDE FLEXIBLE. NOUS AVONS MONTRE IN VITRO ET DANS DES CELLULES EN CULTURE QUE CES DIMERES FORCES PRESENTENT LES MEMES CARACTERISTIQUES QUE LES COMPLEXES NATURELS. NOUS AVONS ENSUITE APPORTE, A L'AIDE DE CE SYSTEME, DES ARGUMENTS SUPPLEMENTAIRES EN FAVEUR D'UNE PARTICIPATION DES DIMERES C-JUN/FRA-1 ET C-JUN/FRA-2 A LA MULTIPLICATION CELLULAIRE. CES MONO-CHAINES CONSTITUENT UN OUTIL ORIGINAL ET EFFICACE PERMETTANT, SANS PERTURBER L'EQUILIBRE DES AUTRES COMPLEXES, D'ANALYSER UN DIMERE AP-1 PARTICULIER.PARIS-BIUSJ-ThĂšses (751052125) / SudocCentre Technique Livre Ens. Sup. (774682301) / SudocPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF
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