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The human liver fulfills several vital tasks daily and possesses an impressive ability to self-regenerate. However, the capacity of this self-healing process can be exhausted by a variety of different liver diseases, such as alcoholic liver damage, viral hepatitis, or hepatocellular carcinoma. Over time, all these diseases generally lead to progressive liver failure that can become fatal if left untreated. Thus, a great effort has been directed towards the development of innovative therapies. The most recently discovered therapies often involve modifying the patient’s immune system to enhance a beneficial immune response. Current data suggest that, among others, the cytokine IL-22 might be a promising therapeutical candidate. IL-22 and its endogenous antagonist, IL-22BP, have been under thorough scientific investigation for nearly 20 years. While IL-22 is mainly produced by TH22 cells, ILC3s, NKT cells, or γδ T cells, sources of IL-22BP include dendritic cells, eosinophils, and CD4+ cells. In many settings, IL-22 was shown to promote regenerative potential and, thus, could protect tissues from pathogens and damage. However, the effects of IL-22 during carcinogenesis are more ambiguous and depend on the tumor entity and microenvironment. In line with its capabilities of neutralizing IL-22 in vivo, IL-22BP possesses often, but not always, an inverse expression pattern compared to its ligand. In this comprehensive review, we will summarize past and current findings regarding the roles of IL-22 and IL-22BP in liver diseases with a particular focus on the leading causes of advanced liver failure, namely, liver infections, liver damage, and liver malignancies.

Machine learning techniques have provided a technological evolution in medicine and especially in the field of medical imaging. The aim of this study is to firstly compare multiple transfer learning architecture models such as MobilleNetVn (n = 1, 2), InceptionVn (n = 1, 2, 3, 4), InceptionResNet, VGG16 and NasNetMobile and provide a final performance estimation, using a variety of metrics, secondly, propose an efficient and accurate classifier for liver cancer trait detection and prediction, and thirdly, develop a mobile application which uses the proposed model to classify liver cancer traits into various categories in real-time. Magnetic Resonance Images (MRI) of mouse liver cancer of different origin were used as input datasets for our experiments. However, the required memory by the deployed Convolutional Neural Network (CNN) models on smart mobile devices or embedded systems for real time applications, is an issue to be addressed. Here, all the baseline pre-trained CNN models on the ImageNet dataset were trained on a dataset of MRI images of mice of different genetic background with genetically- or chemically- induced hepatocellular cancer. We present and compare all main metric values for each model such as accuracy, cross entropy, f-score, confusion matrix for various types of classification. Data analysis verifies that the proposed optimized architecture model for this task of liver cancer trait classification and prediction, the MV1-LCCP, shows a suitable performance in terms of memory utilization and accuracy, suitable to be deployed in the mobile Android application, which is also developed and presented in this paper.

IL-6 signaling via its receptor (IL-6R) and co-receptor (gp130) performs multiple roles in regulating metabolic homeostasis. However, gp130 is also expressed systemically in a soluble form (sgp130), which limits soluble IL-6 receptor (sIL-6R)-mediated signaling – also called trans-signaling. Here we find that transgenic peripheral sgp130-mediated trans-signaling blockade induces mature-onset obesity, while differentially affecting age-dependent behavioral determinants of energy expenditure. In youth, trans-signaling blockade increases feeding associated with reduced leptin sensitivity but increases energy expenditure to maintain metabolic balance. In aging, reduced physical activity predisposes mice to adiposity, adipose tissue macrophage recruitment, hepatosteatosis, hyperglycemia, and insulin resistance. Mechanistically, trans-signaling blockade reduces hepatic Stat3 phosphorylation and suppresses PPARα, associated with miR-21 upregulation, while pharmacological activation of PPARα prevents obesity and hepatosteatosis, and rescues insulin sensitivity. Together these experiments reveal a role for peripheral IL-6 trans-signaling in metabolic homeostasis and provide clinical significance to elevated sgp130 levels found in some obese and diabetic patients.

Background and aimsEndoscopic resection has been established as curative therapy for superficial cancer arising from Barrett’s oesophagus (BE); recurrences are very rare. Based on a case series with unusual and massive early recurrences, we analyse the issue of tumour cell reimplantation.MethodsThis hypothesis was developed on the basis of two out of seven patients treated by circumferential (n=6) or nearly circumferential (n=1) en bloc and R0 endoscopic resection of T1 neoplastic BE. Subsequently, a prospective histocytological analysis of endoscope channels and accessories was performed in 2 phases (cytohistological analysis; test for cell viability) in 22 different oesophageal carcinoma patients undergoing endoscopy. Finally, cultures from two oesophageal adenocarcinoma cell lines were incubated with different triamcinolone concentrations (0.625–10 mg/mL); cell growth was determined on a Multiwell plate reader.ResultsCancer regrowth in the two suspicious cases (male, 78/71 years) occurred 7 and 1 months, respectively, after curative tumour resection. Subsequent surgery showed advanced tumours (T2) with lymph node metastases; one patient died. On cytohistological examinations of channels and accessories, suspicious/neoplastic cells were found in 4/10 superficial and in all 5 advanced cancers. Further analyses in seven further advanced adenocarcinoma cases showed viable cells in two channel washing specimens. Finally, cell culture experiments demonstrated enhanced tumour cell growth by triamcinolone after 24 hours compared with controls.ConclusionsTumour cell reimplanation from contaminated endoscopes and accessories is a possible cause of local recurrence after curative endoscopic therapy for superficial Barrett carcinoma; also, corticosteroid injection could have promoted tumour regrowth in these cases.

The clearance of apoptotic cells by Mφs favors malignant pleural effusion progression in a murine cancer model., Malignant pleural effusion (MPE) results from the capacity of several human cancers to metastasize to the pleural cavity. No effective treatments are currently available, reflecting our insufficient understanding of the basic mechanisms leading to MPE progression. Here, we found that efferocytosis through the receptor tyrosine kinases AXL and MERTK led to the production of interleukin-10 (IL-10) by four distinct pleural cavity macrophage (Mφ) subpopulations characterized by different metabolic states and cell chemotaxis properties. In turn, IL-10 acts on dendritic cells (DCs) inducing the production of tissue inhibitor of metalloproteinases 1 (TIMP1). Genetic ablation of Axl and Mertk in Mφs or IL-10 receptor in DCs or Timp1 substantially reduced MPE progression. Our results delineate an inflammatory cascade—from the clearance of apoptotic cells by Mφs, to production of IL-10, to induction of TIMP1 in DCs—that facilitates MPE progression. This inflammatory cascade offers a series of therapeutic targets for MPE.

Background Prenatal challenges such as maternal stress perception increase the risk and severity of asthma during childhood. However, insights into the trajectories and targets underlying the pathogenesis of prenatally triggered asthma are largely unknown. The developing lung and immune system may constitute such targets. Objective Here we have aimed to identify the differential sex-specific effects of prenatal challenges on lung function, immune response, and asthma severity in mice. Methods We generated bone marrow chimeric (BMC) mice harboring either prenatally stress-exposed lungs or a prenatally stress-exposed immune (hematopoietic) system and induced allergic asthma via ovalbumin. Next-generation sequencing (RNA sequencing) of lungs and assessment of airway epithelial barrier function in ovalbumin-sensitized control and prenatally stressed offspring was also performed. Results Profoundly enhanced airway hyperresponsiveness, inflammation, and fibrosis were exclusively present in female BMC mice with prenatally stress-exposed lungs. These effects were significantly perpetuated if both the lungs and the immune system had been exposed to prenatal stress. A prenatally stress-exposed immune system alone did not suffice to increase the severity of these asthma features. RNA sequencing analysis of lungs from prenatally stressed, non-BMC, ovalbumin-sensitized females unveiled a deregulated expression of genes involved in asthma pathogenesis, tissue remodeling, and tight junction formation. It was also possible to independently confirm a tight junction disruption. In line with this, we identified an altered perinatal and/or postnatal expression of genes involved in lung development along with an impaired alveolarization in female prenatally stressed mice. Conclusion Here we have shown that the fetal origin of asthma is orchestrated by a disrupted airway epithelium and further perpetuated by a predisposed immune system.

IL-22 is a potent pro-inflammatory cytokine upregulated in psoriasis and in other inflammatory diseases. The function of IL-22 is regulated by the soluble scavenging receptor, IL-22 binding protein (IL-22BP or IL-22RA2). However, the role and regulation of IL-22BP itself in the pathogenesis of inflammatory disease remain unclear. We used the TLR7 agonist Imiquimod (IMQ) to induce a psoriasis-like skin disease in mice and found a strong downregulation of IL-22BP in the affected skin as well as in the lymph nodes of animals treated with IMQ. We also analysed psoriatic skin of patients and compared this to skin of healthy donors. Interestingly, IL-22BP expression was similarly downregulated in skin biopsies of psoriasis patients compared to the skin of healthy donors. Since IL-22BP is expressed foremost in dendritic cells, we characterized its expression in monocyte-derived dendritic cells (MoDC) during maturation. In this way, we found Prostaglandin E2 (PGE2) to be a potent suppressor of IL-22BP expression in vitro. We conclude that regulation of IL-22BP by inflammatory mediators is an important step for the progression of inflammation in the skin and possibly also in other autoimmune diseases.

Acute liver injury can be secondary to a variety of causes, including infections, intoxication, and ischemia. All of these insults induce hepatocyte death and subsequent inflammation, which can make acute liver injury a life-threatening event. IL-22 is a dual natured cytokine which has context-dependent protective and pathogenic properties during tissue damage. Accordingly, IL-22 was shown to promote liver regeneration upon acute liver damage. However, other studies suggest pathogenic properties of IL-22 during chronic liver injury. IL-22 binding protein (IL-22BP, IL-22Ra2) is a soluble inhibitor of IL-22 that regulates IL-22 activity. However, the significance of endogenous IL-22BP in acute liver injury is unknown. We hypothesized that IL-22BP may play a role in acute liver injury. To test this hypothesis, we used Il22bp-deficient mice and murine models of acute liver damage induced by ischemia reperfusion and N-acetyl-p-aminophenol (acetaminophen) administration. We found that Il22bp-deficient mice were more susceptible to acute liver damage in both models. We used Il22 × Il22bp double-deficient mice to show that this effect is indeed due to uncontrolled IL-22 activity. We could demonstrate mechanistically increased expression of Cxcl10 by hepatocytes, and consequently increased infiltration of inflammatory CD11b+Ly6C+ monocytes into the liver in Il22bp-deficient mice upon liver damage. Accordingly, neutralization of CXCL10 reversed the increased disease susceptibility of Il22bp-deficient mice. In conclusion, our data indicate that IL-22BP plays a protective role in acute liver damage, via controlling IL-22–induced Cxcl10 expression.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Lung cancer and chronic lung diseases impose major disease burdens worldwide and are caused by inhaled noxious agents including tobacco smoke. The cellular origins of environmental-induced lung tumors and of the dysfunctional airway and alveolar epithelial turnover observed with chronic lung diseases are unknown. To address this, we combined mouse models of genetic labeling and ablation of airway (club) and alveolar cells with exposure to environmental noxious and carcinogenic agents. Club cells are shown to survive KRAS mutations and to form lung tumors after tobacco carcinogen exposure. Increasing numbers of club cells are found in the alveoli with aging and after lung injury, but go undetected since they express alveolar proteins. Ablation of club cells prevents chemical lung tumors and causes alveolar destruction in adult mice. Hence club cells are important in alveolar maintenance and carcinogenesis and may be a therapeutic target against premalignancy and chronic lung disease., eLife digest The deadliest form of lung cancer is called lung adenocarcinoma, or LUAD. Tobacco chemicals often cause the disease by damaging the genetic information of lung cells. The damage leads to harmful changes in the DNA sequence which prompt the cells to form tumors. For instance, the most common of these changes takes place in a gene called KRAS. However, it is still unclear exactly which type of lung cells are more likely to develop into a tumor. In the lungs, airway epithelial cells cover the inside of the passages that bring the air inside little sacks called alveoli, which are lined by alveolar cells. Previous studies have used genetic methods to switch on the KRAS mutation in different compartments of the mouse lung. This showed that groups of airway cells, of alveolar cells, and of a class of cells located at the junction between airways and alveoli could all give rise to cancer. However, these experiments did not examine how tobacco chemicals could give rise to tumors in different groups of lung cells. Here, Spella et al. triggered LUAD in adult mice by exposing them to the toxic chemicals found in tobacco smoke, but without making any change to the KRAS gene. These mice also had genetically engineered reporters that could be used to deduce where the resulting tumors came from. DNA sequencing showed that the airway epithelial cells gained KRAS mutations after the chemical treatment. When the airway epithelial cells were experimentally removed before the treatments with tobacco chemicals, these mice did not get LUAD tumors. Spella et al. also observed that the tobacco-induced tumors came from the epithelial cells in the airways, and not from the cells in the alveoli. Moreover, when the lung was damaged, airway cells could move to the alveoli and start adopting the identity of alveolar cells, thereby replenishing this population. Together, these experiments imply that tobacco-induced LUAD starts in the airway epithelial cells. These findings suggest that airway epithelial cells could be targeted to stop lung cancer early on. Further studies should also examine how airway epithelial cells can transition to look more like alveolar cells when the lungs get harmed.

A Marazioti,1 K Papadia,2 A Giannou,3 GT Stathopoulos,3,4 SG Antimisiaris1,21Foundation for Research and Technology Hellas, Institute of Chemical Engineering Sciences (FORTH/ICE-HT), Rio, Greece; 2Laboratory of Pharmaceutical Technology, Department of Pharmacy, University of Patras, Rio, Greece; 3Laboratory for Molecular Respiratory Carcinogenesis, Department of Physiology, Faculty of Medicine, University of Patras, Rio Greece; 4Comprehensive Pneumonology Center and Institute for Lung Biology and Disease, University Hospital, Ludwig-Maximilians University and Helmholtz Center Munich, Munich, GermanyBackground: Intrapleural administration of compounds is a lung targeted, innovative therapeutic strategy for mesothelioma, which can be refined as a route for drug delivery that minimizes the potential for systemic toxicity. However, little is currently known about the retention of liposomal drugs at the site, after such topical administration.Purpose: To evaluate the retention of liposomes in lungs following intrapleural injection, and how this might be modulated by liposome properties and disease progression.Methods: DiR-incorporating liposomes with various lipid compositions and sizes were prepared, characterized (for size distribution and zeta potential) and injected intrapleurally in normal mice and mice with malignant pleural effusion (MPE). DiR retention in pleural cavity was followed by biofluorescence imaging.Results: Experimental results demonstrate that liposome size and PEG-coating, have a significant effect on residence time in the pleural cavity; negative surface charge does not. More than 20% liposomal-DiR is retained 24 d post-injection (in some cases), indicating the high potential towards localized diseases. Ex-vivo liposomal-DiR signal in tumors of MPE mice was similar to signal in liver, suggesting high tumor targeting potential of intrapleurally injected liposomes. Finally, no difference was noticed in liposomal-DiR retention between tumor-inoculated (MPE) and healthy mice, indicating the stability of liposomes in the presence of effusion (in MPE mice).Conclusion: The current study provides novel insights for using liposomes by intrapleural administration for the treatment of lung diseases.Keywords: nanoparticles, sustained release, local administration, lung, cancer, mesothelioma

Lung adenocarcinoma (LUAD) and chronic lung diseases caused by smoking and environmental noxious agents are the deadliest diseases worldwide, sharing a partially charted pathobiology of dysfunctional alveolar repair. Here we sought to identify the respiratory epithelial dynamics and molecular signatures participating in adult lung maintenance and chemical carcinogenesis. We employed novel mouse models of respiratory epithelial marking and ablation, a battery of pulmonary toxins and carcinogens, experimental protocols of carcinogen-induced LUAD, tobacco carcinogen-induced LUAD cell lines, and human transcriptomic data and identified a prominent involvement of airway molecular programs in alveolar maintenance and carcinogen-induced LUAD. The airway-specific transcriptomic signature was redistributed to the alveoli after toxic and carcinogenic insults and resulted in marked contributions of airway-labeled cells to injury-recovered alveoli and LUAD. Airway cells maintained Kras mutations and therefore possibly contributed to lung cancer initiation, while LUAD were spatially linked to neighboring airways. Transcriptomic profiling of carcinogen-induced murine and human LUAD revealed enrichment in airway signatures, while ablation of airway cells distorted alveolar structure and function and protected mice from LUAD development. Collectively, these results indicate that airway cells and/or transcriptomic signatures are essential for alveolar maintenance and LUAD development.

Background & Aims Unregulated activity of interleukin (IL) 22 promotes intestinal tumorigenesis in mice. IL22 binds the antagonist IL22 subunit alpha 2 (IL22RA2, also called IL22BP). We studied whether alterations in IL22BP contribute to colorectal carcinogenesis in humans and mice. Methods We obtained tumor and nontumor tissues from patients with colorectal cancer (CRC) and measured levels of cytokines by quantitative polymerase chain reaction, flow cytometry, and immunohistochemistry. We measured levels of Il22bp messenger RNA in colon tissues from wild-type, Tnf–/–, Lta–/–, and Ltb–/– mice. Mice were given azoxymethane and dextran sodium sulfate to induce colitis and associated cancer or intracecal injections of MC38 tumor cells. Some mice were given inhibitors of lymphotoxin beta receptor (LTBR). Intestine tissues were analyzed by single-cell sequencing to identify cell sources of lymphotoxin. We performed immunohistochemistry analysis of colon tissue microarrays from patients with CRC (1475 tissue cores, contained tumor and nontumor tissues) and correlated levels of IL22BP with patient survival times. Results Levels of IL22BP were decreased in human colorectal tumors, compared with nontumor tissues, and correlated with levels of lymphotoxin. LTBR signaling was required for expression of IL22BP in colon tissues of mice. Wild-type mice given LTBR inhibitors had an increased tumor burden in both models, but LTBR inhibitors did not increase tumor growth in Il22bp–/– mice. Lymphotoxin directly induced expression of IL22BP in cultured human monocyte–derived dendritic cells via activation of nuclear factor κB. Reduced levels of IL22BP in colorectal tumor tissues were associated with shorter survival times of patients with CRC. Conclusions Lymphotoxin signaling regulates expression of IL22BP in colon; levels of IL22BP are reduced in human colorectal tumors, associated with shorter survival times. LTBR signaling regulates expression of IL22BP in colon tumors in mice and cultured human dendritic cells. Patients with colorectal tumors that express low levels of IL22BP might benefit from treatment with an IL22 antagonist.

Introduction Reflux promotes esophageal adenocarcinomas (EAC) creating a chronic inflammatory environment. EAC show an increasing incidence in the Western World and median survival rates are still low. The main reasons for poor prognosis despite new multimodal therapies are diagnosis of EACs at an already advanced stage and distant metastases. Hence, we wanted to investigate the presence of systemic inflammatory interleukins (IL) and their impact on patient prognosis. Material and methods Systemic expression levels of pro- and anti-inflammatory markers (IL-2, IL-4, IL-6, IL-10, IL-17A and IL-22) in the sera of 43 EAC patients without neoadjuvant radiochemotherapy were measured by flow cytometric analysis. A correlation to clinicopathological data was performed. Log-rank and Cox regression analysis were used to investigate the impact on patient survival. 43 sera of age and gender matched healthy volunteers were used as controls. Results Increased systemic IL-6 (p = 0.044) and lower IL-17A (p = 0.002) levels were found in EAC patients as opposed to controls. A correlation of IL-10 levels with an increased T stage was found (p = 0.020). Also, systemic IL-10 levels were highly elevated in patients with distant metastasis (p

Malignant pleural effusion (MPE) is a frequent metastatic manifestation of human cancers. While we previously identified KRAS mutations as molecular culprits of MPE formation, the underlying mechanism remained unknown. Here, we determine that non-canonical IKKα-RelB pathway activation of KRAS-mutant tumor cells mediates MPE development and this is fueled by host-provided interleukin IL-1β. Indeed, IKKα is required for the MPE-competence of KRAS-mutant tumor cells by activating non-canonical NF-κB signaling. IL-1β fuels addiction of mutant KRAS to IKKα resulting in increased CXCL1 secretion that fosters MPE-associated inflammation. Importantly, IL-1β-mediated NF-κB induction in KRAS-mutant tumor cells, as well as their resulting MPE-competence, can only be blocked by co-inhibition of both KRAS and IKKα, a strategy that overcomes drug resistance to individual treatments. Hence we show that mutant KRAS facilitates IKKα-mediated responsiveness of tumor cells to host IL-1β, thereby establishing a host-to-tumor signaling circuit that culminates in inflammatory MPE development and drug resistance., Malignant pleural effusion (MPE) is a life-threatening cancer-related disorder. Here, the authors show that KRAS-mutant tumor cells require IKKα, activated via host-provided IL-1β, to promote MPE development and that co-inhibition of both KRAS and IKKα ameliorates the development of MPE in mouse models.

Malignant pleural effusion (MPE) is the lethal consequence of various human cancers metastatic to the pleural cavity. However, the mechanisms responsible for the development of MPE are still obscure. Here we show that mutant KRAS is important for MPE induction in mice. Pleural disseminated, mutant KRAS bearing tumour cells upregulate and systemically release chemokine ligand 2 (CCL2) into the bloodstream to mobilize myeloid cells from the host bone marrow to the pleural space via the spleen. These cells promote MPE formation, as indicated by splenectomy and splenocyte restoration experiments. In addition, KRAS mutations are frequently detected in human MPE and cell lines isolated thereof, but are often lost during automated analyses, as indicated by manual versus automated examination of Sanger sequencing traces. Finally, the novel KRAS inhibitor deltarasin and a monoclonal antibody directed against CCL2 are equally effective against an experimental mouse model of MPE, a result that holds promise for future efficient therapies against the human condition., Malignant pleural effusion (MPE) is a lethal condition associated with various cancers. Here, the authors show that cancer cells with KRAS mutations promote MPE by recruiting myeloid cells via CCL2 signalling and that pharmaceutical targeting of KRAS results in reduced MPE incidence and volume in mouse models.

Background Nuclear factor (NF)-kB activation is essential for KRAS-mutant lung adenocarcinoma (Stathopoulos, G.T. et al. Proc Natl Acad Sci U S A 2007;104:18514-9 and Meylan, E. et al. Nature 2009;462:104-7). However, the relative contributions of NF-kB-activating kinases IKKa and IKKb are unknown. Aims To monitor and block NF-kB activation and IKK functions in lung adenocarcinoma. Methods NF-kB reporter mice and conditional IKKa/b gene deleted mice were used, which, respectively, express firefly luciferase in all somatic cells upon NF-kB activation, or lose the respective IKK gene upon CRE-mediated recombination. Lung adenocarcinomas were induced in these mice via ip injection of urethane (1 g/Kg) that is a tobacco carcinogen. Mutant KRAS-IKK interactions were studied using transfected benign HEK293T cells with mutant KRAS-and/or IKK-expression vectors. IKK-inhibitors are used in ADCA cell lines and KRAS-induced mice. Results Urethane caused strong NF-kB activation in the lungs, characterized by significant induction and nuclear translocation of IKKa, but not IKKb. Deletion of IKKa from the respiratory epithelium resulted in almost complete eradication of urethane-induced KRAS-mutant lung tumors, while deletion of IKKb was less protective. IKKb, but not IKKa, functioned as a tumor promoter in KRAS-wild-type HEK293T cells. However, only IKKa, and not IKKb, could render mutant KRAS-expressing HEK293T cells oncogenic in immunocompromized mice. In KRAS-IKKa-addicted tumorigenic HEK293T cells, IKKa resided in the nucleus.Dual IKK inhibitor is more effective in our models than IKKb inhibitor. Conclusions IKKa is required for KRAS-mediated lung adenocarcinoma. Funding European Research Council Starting Independent Investigator Grant #260524. This abstract has been presented previously at the European Respiratory Society9s Lung Science Conference in March 2016 .

Osteopontin (SPP1) expression has been identified in human lung cancer and has been linked with enhanced tumor progression. To examine its functional role, we induced lung tumors by repetitive urethane or MCA/BHT lung carcinogens in C57BL/6 mice lacking both ( Spp1-/- ), one ( Spp1+/- ), or no ( Spp1+/+ ) copy of the endogenous Spp1 gene. Primary end-points were lung tumor number and size; secondary end-points were SPP1 expression, epithelial cell survival, carcinogen-induced inflammation, and angiogenesis. Data are presented as mean±SD. Compared with Spp1+/+ mice (n=22), Spp1-/- mice (n=25) developed dramatically fewer and significantly smaller lung tumors in response to urethane, while Spp1+/- mice (n=12) behaved similar to Spp1-/- mice (number/diameter of lung tumors in Spp1+/+ , Spp1+/- , and Spp1-/- mice, respectively: 16.1±12.7/1.2±0.3 mm, 2.4±2.3/0.9±0.2 mm, and 1.3±1.6/0.7±0.2 mm; P Spp1+/+ with Spp1-/- and Spp1+/- mice). Spp1-/- mice were also protected from two-hit MCA/BHT-oncogenesis compared with Spp1+/+ controls. Spp1-/- mice displayed decreased epithelial cell survival and reduced numbers of airspace macrophages early after urethane, and enhanced tumor cell apoptosis and limited tumor angiogenesis at late stages of lung tumor progression. SPP1 was expressed in the naive lung by non-ciliated airway epithelial cells and alveolar macrophages and was significantly up-regulated during multi-stage lung carcinogenesis. SPP1 also initiated the survival of mutant Kras cells. Our data indicate that SPP1 is functionally involved in airway epithelial carcinogenesis via survival of mutant Kras cells and may present a target for lung cancer treatment and prevention.

Background: The immune cells that facilitate malignant pleural effusion (MPE), an immune-mediated end-stage cancer manifestation (Stathopoulos, G.T. et al. Am J Respir Crit Care Med 2012;186:487-92), have not been identified. Aims: We found mast cells (MC) in MPE and investigated their functions. Methods: Human and experimental MPE were assessed for MC content.MPE was induced by intrapleurally injected Lewis lung (LLC) and MC38 colon adenocarcinoma cells in Wt and two separate strains of MC-deficient ( cKitWsh, Cpa3.Cre ) mice. Bone marrow-derived MC were used for MC cell fate and restoration studies. Tumor cells and tumor-exposed MC were subjected to transcriptional profiling. Results: We discovered and characterized MC in human and murine MPE. Cell fate models conveyed that MC were attracted to MPE by tumor-derived CCL2 to be locally degranulated by osteopontin. Both cKitWsh and Cpa3 . Cre mice were protected from MPE induced by both LLC and MC38 cells (mean±SD MPE volume of C57BL/6, cKitWsh and Cpa3 . Cre mice induced by LLC cells: 573±242, 108±130, and 277±284µL; and by MC38 cells: 864±310, 278±323, and 464±203 µL; n = 7-23/group; P Conclusions: Adenocarcinomas instate circuitry with MC to induce MPE once metastatic in the pleural space. Acknowledgements: Supported by ERC-2010-StG-#260524 anda Hellenic Thoracic Society 2012 Research Award.

Background: EGFR/KRAS axis mutations are frequent in human malignantpleuraleffusions (MPE). Aims: To investigate the relationship between perturbations in the EGFR-KRAS axis and malignant pleural effusion development. Methods: Several mouse and human cancer cell lines were characterized for EGFR/KRAS status and for their MPE competence in appropriate hosts. EGFR/KRAS signalling was modulated in various cell lines via standard molecular techniques. MPE-associated inflammation was monitored by bioluminescence imaging, immunophenotyped by flow cytometry, and modulated by splenectomy and adoptive bone marrow transfer. EGFR/KRAS axis was targeted using gefitinib, deltarasin, and anti-CCL2 antibodies. Results: A causative relationship between Δ Kras and MPEwas established by showing that mouse and human cancer cell lines bearing Δ Kras are MPE competent and that activated Kras is capable of conferring MPE competency to human and mouse cells. Furthermore, Kras dependent downstream paracrine signaling to bone marrow activated a distinct GR1+/CD11B+ myeloid cell population, which is maturing in the spleen and is consequently recruited to the pleural cavity in a cancer-elaborated CCL2-dependent way. Splenectomy partially protects hosts from MPE. The pharmacological manipulation of Δ EGFR/ Δ KRAS axis with Gefitinib (targeting Δ EGFR ) or Deltarasin (targeting Δ KRAS ) and the antibody-mediated neutralization of CCL2 completely annihilate MPE formation and the recruitment of CD11b+/GR1+ cells to the pleura. Conclusions: Our work provides insights to MPE pathobiology and a multitude of strategies to target a currently untreatable terminal human condition. Funding: European Research Council Starting Independent Investigator Grant #260524.

Using genetic interventions, we previously determined that C-C motif chemokine ligand 2 (CCL2) promotes malignant pleural effusion (MPE) formation in mice. Here we conducted preclinical studies aimed at assessing the specific therapeutic potential of antibody-mediated CCL2 blockade against MPE. For this, murine MPEs or skin tumors were generated in C57BL/6 mice by intrapleural or subcutaneous delivery of lung (LLC) or colon (MC38) adenocarcinoma cells. Human lung adenocarcinoma cells (A549) were used to induce MPEs in severe combined immunodeficient mice. Intraperitoneal antibodies neutralizing mouse CCL2 and/or CCL12, a murine CCL2 ortholog, were administered at 10 or 50 mg/kg every three days. We found that high doses of CCL2/12 neutralizing antibody treatment (50 mg/kg) were required to limit MPE formation by LLC cells. CCL2 and CCL12 blockade were equally potent inhibitors of MPE development by LLC cells. Combined CCL2 and CCL12 neutralization was also effective against MC38-induced MPE and prolonged the survival of mice in both syngeneic models. Mouse-specific CCL2-blockade limited A549-caused xenogeneic MPE, indicating that host-derived CCL2 also contributes to MPE precipitation in mice. The impact of CCL2/12 antagonism was associated with inhibition of immune and vascular MPE-related phenomena, such as inflammation, new blood vessel assembly and plasma extravasation into the pleural space. We conclude that CCL2 and CCL12 blockade are effective against experimental MPE induced by murine and human adenocarcinoma in mice. These results suggest that CCL2-targeted therapies may hold promise for future use against human MPE.