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Find video protocols related to scientific articles indexed in Pubmed.
Intraductal neoplasms of the pancreas.
Semin Diagn Pathol
PUBLISHED: 10-06-2014
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There are three types of pancreatic neoplasms that predominantly have an intraductal growth pattern: the common, usually cystic, intraductal papillary mucinous neoplasms (IPMNs); the rare, usually solid intraductal tubulopapillary neoplasms (ITPNs); and the rare intraductal tubular pyloric gland-type adenoma. In addition to these three tumor types, pancreatic neoplasms with a usually solid growth pattern such as acinar cell carcinomas, neuroendocrine tumors, and undifferentiated carcinomas may present, though very rarely, as predominantly intraductally growing neoplasms. IPMNs can be subclassified into main duct and branch duct tumors; into low- and high-grade dysplasia groups; and into tumors with intestinal, pancreatobiliary, oncocytic, or gastric cellular differentiation. The intestinal-, pancreatobiliary-, and oncocytic-type IPMNs occur predominantly in the main duct of the head of the pancreas and more commonly progress to invasive adenocarcinomas. The gastric-type IPMNs are frequently multifocal, occur predominantly in the branch ducts of the uncinate process, and have a low risk of progressing to invasive carcinoma. The prognosis for patients with an IPMN depends largely on the subtype and the presence and the stage of an invasive carcinoma. ITPNs are nodular tumors, often in the pancreatic head, and composed of densely packed tubular glands. Molecular genetics reveal KRAS, GNAS, and RNF43 as the most frequently mutated genes in IPMNs, while ITPNs show wild-type KRAS. Recent progress in genetic sequencing of pancreatic neoplasms and the identification of specific genetic mutations also holds promise for the future development of novel gene-based diagnostic tests in intraductal neoplasms of the pancreas that might even be used in preoperative conditions.
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Inactivation of the ferroptosis regulator Gpx4 triggers acute renal failure in mice.
Nat. Cell Biol.
PUBLISHED: 08-13-2014
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Ferroptosis is a non-apoptotic form of cell death induced by small molecules in specific tumour types, and in engineered cells overexpressing oncogenic RAS. Yet, its relevance in non-transformed cells and tissues is unexplored and remains enigmatic. Here, we provide direct genetic evidence that the knockout of glutathione peroxidase 4 (Gpx4) causes cell death in a pathologically relevant form of ferroptosis. Using inducible Gpx4(-/-) mice, we elucidate an essential role for the glutathione/Gpx4 axis in preventing lipid-oxidation-induced acute renal failure and associated death. We furthermore systematically evaluated a library of small molecules for possible ferroptosis inhibitors, leading to the discovery of a potent spiroquinoxalinamine derivative called Liproxstatin-1, which is able to suppress ferroptosis in cells, in Gpx4(-/-) mice, and in a pre-clinical model of ischaemia/reperfusion-induced hepatic damage. In sum, we demonstrate that ferroptosis is a pervasive and dynamic form of cell death, which, when impeded, promises substantial cytoprotection.
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Evaluation of colon cancer histomorphology: a comparison between formalin and PAXgene tissue fixation by an international ring trial.
Virchows Arch.
PUBLISHED: 04-10-2014
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The aim of our study was to evaluate the quality of histo- and cytomorphological features of PAXgene-fixed specimens and their suitability for histomorphological classification in comparison to standard formalin fixation. Fifteen colon cancer tissues were collected, divided into two mirrored samples and either formalin fixed (FFPE) or PAXgene fixed (PFPE) before paraffin embedding. HE- and PAS-stained sections were scanned and evaluated in a blinded, randomised ring trial by 20 pathologists from Europe and the USA using virtual microscopy. The pathologists evaluated histological grading, histological subtype, presence of adenoma, presence of lymphovascular invasion, quality of histomorphology and quality of nuclear features. Statistical analysis revealed that the reproducibility with regard to grading between both fixation methods was rather satisfactory (weighted kappa statistic (k w)?=?0.73 (95 % confidence interval (CI), 0.41-0.94)), with a higher agreement between the reference evaluation and the PFPE samples (k w?=?0.86 (95 % CI, 0.67-1.00)). Independent from preservation method, inter-observer reproducibility was not completely satisfactory (k w?=?0.60). Histomorphological quality parameters were scored equal or better for PFPE than for FFPE samples. For example, overall quality and nuclear features, especially the detection of mitosis, were judged significantly better for PFPE cases. By contrast, significant retraction artefacts were observed more frequently in PFPE samples. In conclusion, our findings suggest that the PAXgene Tissue System leads to excellent preservation of histomorphology and nuclear features of colon cancer tissue and allows routine morphological diagnosis.
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Inflammation-induced NFATc1-STAT3 transcription complex promotes pancreatic cancer initiation by KrasG12D.
Cancer Discov
PUBLISHED: 04-02-2014
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Cancer-associated inflammation is a molecular key feature in pancreatic ductal adenocarcinoma. Oncogenic KRAS in conjunction with persistent inflammation is known to accelerate carcinogenesis, although the underlying mechanisms remain poorly understood. Here, we outline a novel pathway whereby the transcription factors NFATc1 and STAT3 cooperate in pancreatic epithelial cells to promote Kras(G12D)-driven carcinogenesis. NFATc1 activation is induced by inflammation and itself accelerates inflammation-induced carcinogenesis in Kras(G12D) mice, whereas genetic or pharmacologic ablation of NFATc1 attenuates this effect. Mechanistically, NFATc1 complexes with STAT3 for enhancer-promoter communications at jointly regulated genes involved in oncogenesis, for example, Cyclin, EGFR and WNT family members. The NFATc1-STAT3 cooperativity is operative in pancreatitis-mediated carcinogenesis as well as in established human pancreatic cancer. Together, these studies unravel new mechanisms of inflammatory-driven pancreatic carcinogenesis and suggest beneficial effects of chemopreventive strategies using drugs that are currently available for targeting these factors in clinical trials.
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Update on surgical treatment of pancreatic neuroendocrine neoplasms.
World J. Gastroenterol.
PUBLISHED: 03-05-2014
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Pancreatic neuroendocrine neoplasms (PNENs) are rare and account for only 2%-4% of all pancreatic neoplasms. All PNENs are potential (neurendocrine tumors PNETs) or overt (neuroendocrine carcinomas PNECs) malignant, but a subset of PNETs is low-risk. Even in case of low-risk PNETs surgical resection is frequently required to treat hormone-related symptoms and to obtain an appropriate pathological diagnosis. Low-risk PNETs in the body and the tail are ideal for minimally-invasive approaches which should be tailored to the individual patient. Generally, surgeons must aim for parenchyma sparing in these cases. In high-risk and malignant PNENs, indications for tumor resection are much wider than for pancreatic adenocarcinoma, in many cases due to the relatively benign tumor biology. Thus, patients with locally advanced and metastatic PNETs may benefit from extensive resection. In experienced hands, even multi-organ resections are accomplished with acceptable perioperative morbidity and mortality rates and are associated with excellent long term survival. However, poorly differentiated neoplasms with high proliferation rates are associated with a dismal prognosis and may frequently only be treated with chemotherapy. The evidence on surgical treatment of PNENs stems from reviews of mostly single-center series and some analyses of nation-wide tumor registries. No randomized trial has been performed to compare surgical and non-surgical therapies in potentially resectable PNEN. Though such a trial would principally be desirable, ethical considerations and the heterogeneity of PNENs preclude realization of such a study. In the current review, we summarize recent advances in the surgical treatment of PNENs.
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MicroRNA-196a and -196b as Potential Biomarkers for the Early Detection of Familial Pancreatic Cancer.
Transl Oncol
PUBLISHED: 02-24-2014
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Screening programs are recommended for individuals at risk (IAR) from families with familial pancreatic cancer (FPC). However, reliable imaging methods or biomarkers for early diagnosis of pancreatic ductal adenocarcinoma (PC) or its precursor lesions are still lacking. The ability of circulating microRNAs (miRNAs) to discriminate multifocal high-grade precursor lesions or PC from normal was examined. The presence of miRNA-21, -155, -196a, -196b and -210 was analyzed in the serum of transgenic KPC mice to test their ability to distinguish mice with different grades of pancreatic intraepithelial neoplasia (mPanIN1-3) or PC from control mice. Serum levels of miR-196a and -196b were significantly higher in mice with PanIN2/3 lesions (n = 10) or PC (n = 8) as compared to control mice (n = 10) or mice with PanIN1 lesions (n = 10; P = .01). In humans, miR-196a and -196b were also diagnostic. Patients with PC, sporadic (n = 9) or hereditary (n = 10), and IAR with multifocal PanIN2/3 lesions (n = 5) had significantly higher serum levels than patients with neuroendocrine pancreatic tumors (n = 10) or chronic pancreatitis (n = 10), IAR with PanIN1 or no PanIN lesions (n = 5), and healthy controls (n = 10). The combination of both miR-196a and -196b reached a sensitivity of 1 and specificity of 0.9 (area under the curve = 0.99) to diagnose PC or high-grade PanIN lesions. In addition, preoperative elevated serum levels of miR-196a and -196b in patients with PC or multifocal PanIN2/3 lesions dropped to normal after potential curative resection. The combination of miR-196a and -196b may be a promising biomarker test for the screening of IAR for FPC.
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Multimodal molecular imaging of integrin ?v?3 for in vivo detection of pancreatic cancer.
J. Nucl. Med.
PUBLISHED: 02-18-2014
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Pancreatic ductal adenocarcinoma (PDAC) is a lethal disease. Late detection of then nonresectable or metastasized tumors emphasizes the need for novel imaging approaches. Here, we report on so far nonexploited potentials of ?v?3 integrin-targeted molecular imaging technologies for detection of PDAC using genetically engineered mouse models.
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Ebf factors and MyoD cooperate to regulate muscle relaxation via Atp2a1.
Nat Commun
PUBLISHED: 02-12-2014
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Myogenic regulatory factors such as MyoD and Myf5 lie at the core of vertebrate muscle differentiation. However, E-boxes, the cognate binding sites for these transcription factors, are not restricted to the promoters/enhancers of muscle cell-specific genes. Thus, the specificity in myogenic transcription is poorly defined. Here we describe the transcription factor Ebf3 as a new determinant of muscle cell-specific transcription. In the absence of Ebf3 the lung does not unfold at birth, resulting in respiratory failure and perinatal death. This is due to a hypercontractile diaphragm with impaired Ca(2+) efflux-related muscle functions. Expression of the Ca(2+) pump Serca1 (Atp2a1) is downregulated in the absence of Ebf3, and its transgenic expression rescues this phenotype. Ebf3 binds directly to the promoter of Atp2a1 and synergises with MyoD in the induction of Atp2a1. In skeletal muscle, the homologous family member Ebf1 is strongly expressed and together with MyoD induces Atp2a1. Thus, Ebf3 is a new regulator of terminal muscle differentiation in the diaphragm, and Ebf factors cooperate with MyoD in the induction of muscle-specific genes.
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Pathology of pancreatic ductal adenocarcinoma: Facts, challenges and future developments.
World J. Gastroenterol.
PUBLISHED: 01-02-2014
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Despite major improvements concerning its diagnosis and treatment, pancreatic ductal adenocarcinoma (PDAC) remains an aggressive disease with an extremely poor prognosis. Pathology, as interface discipline between basic and clinical medicine, has substantially contributed to the recent developments and has laid the basis for further progress. The definition and classification of precursor lesions of PDAC and their molecular characterization is a fundamental step for the potential identification of biomarkers and the development of imaging methods for early detection. In addition, by integrating findings in humans with the knowledge acquired through the investigation of transgenic mouse models for PDAC, a new model for pancreatic carcinogenesis has been proposed and partially validated in individuals with genetic predisposition for PDAC. The introduction and validation of a standardized system for pathology reporting based on the axial slicing technique has shown that most pancreatic cancer resections are R1 resections and that this is due to inherent anatomical and biological properties of PDAC. This standardized assessment of prognostic relevant parameters represents the basis for the successful conduction of multicentric studies and for the interpretation of their results. Finally, recent studies have shown that distinct molecular subtypes of PDAC exist and are associated with different prognosis and therapy response. The prospective validation of these results and the integration of molecular analyses in a comprehensive pathology report in the context of individualised cancer therapy represent a major challenge for the future.
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Antifibrotic properties of transarterial oncolytic VSV therapy for hepatocellular carcinoma in rats with thioacetamide-induced liver fibrosis.
Mol. Ther.
PUBLISHED: 07-25-2013
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Recombinant vesicular stomatitis virus (VSV) shows promise for the treatment of hepatocellular carcinoma (HCC), but its safety and efficacy when administered in a setting of hepatic fibrosis, which occurs in the majority of clinical cases, is unknown. We hypothesized that VSV could provide a novel benefit to the underlying fibrosis, due to its ability to replicate and cause cell death specifically in activated hepatic stellate cells. In addition to the ability of VSV to produce a significant oncolytic response in HCC-bearing rats in the background of thioacetamide-induced hepatic fibrosis without signs of hepatotoxicity, we observed a significant downgrading of fibrosis stage, a decrease in collagen content in the liver, and modulation of gene expression in favor of fibrotic regression. Together, this work suggests that VSV is not only safe and effective for the treatment of HCC with underlying fibrosis, but it could potentially be developed for clinical application as a novel antifibrotic agent.
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Claudin 18.2 is a target for IMAB362 antibody in pancreatic neoplasms.
Int. J. Cancer
PUBLISHED: 05-17-2013
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The majority of pancreatic neoplasms are characterized by a generally lethal progress within a short period of time after primary diagnosis and the mortality of patients is expected to increase further. Due to lack of efficient screening programs and moderate response to treatments, novel compounds for treatment are needed. We investigated the CLDN18.2 expression in affected patients as in vitro feasibility study for a potential treatment with the novel antibody IMAB362. Therefore, we analyzed the expression of CLDN18.2 in normal pancreatic tissues (N = 24), primary lesions (N = 202), metastases (N = 84) and intra-individually matched samples (N = 48) of patients with pancreatic ductal adenocarcinoma (PDAC), neuroendocrine neoplasia (NEN) and acinar cell carcinoma. A standardized method for evaluation by immunohistochemistry was developed. The specific staining was evaluated by two independent raters and analysis of staining intensities (range 0-3+) and relative proportions of tumor cells were performed. One hundred three (59.2%) samples of primary PDAC were found positive. The vast majority of positive samples were characterized to highly express CLDN18.2: 54.6% (N = 95) with staining intensities of ? 2+. NEN were positive in 20% of cases (all ? 2+). Metastases of pancreatic neoplasms were also frequently found positive with comparable high rates (69.4% of lymph node and 65.7% of liver metastases). The rate of CLDN18.2 positivity is high in pancreatic neoplasms whereby the expression is not limited to the primaries but is also maintained upon metastasis. Thus, a considerable number of patients with pancreatic neoplasms would be in principle eligible for a CLDN18.2-targeting approach.
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Precancerous lesions of the biliary tree.
Best Pract Res Clin Gastroenterol
PUBLISHED: 04-11-2013
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The neoplasms of the biliary tree include the carcinomas of the intra- and extrahepatic bile ducts, the gallbladder and the ampulla. Two types of precancerous lesions precede these adenocarcinomas: the flat and non-tumour forming type that is called biliary intraepithelial neoplasia, and the papillary and tumour-forming type that has been named intraductal papillary neoplasm of the bile duct. Rarely also biliary mucinous cystic neoplasm can give rise to invasive biliary adenocarcinomas. This review discusses the pathological, molecular, epidemiological, clinical and prognostic features of the precancerous biliary lesions, separated according to their origin in the bile ducts, the ampulla and the gall bladder.
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Tenascin-C downregulates wnt inhibitor dickkopf-1, promoting tumorigenesis in a neuroendocrine tumor model.
Cell Rep
PUBLISHED: 03-20-2013
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The extracellular matrix molecule tenascin-C (TNC) is a major component of the cancer-specific matrix, and high TNC expression is linked to poor prognosis in several cancers. To provide a comprehensive understanding of TNCs functions in cancer, we established an immune-competent transgenic mouse model of pancreatic ?-cell carcinogenesis with varying levels of TNC expression and compared stochastic neuroendocrine tumor formation in abundance or absence of TNC. We show that TNC promotes tumor cell survival, the angiogenic switch, more and leaky vessels, carcinoma progression, and lung micrometastasis. TNC downregulates Dickkopf-1 (DKK1) promoter activity through the blocking of actin stress fiber formation, activates Wnt signaling, and induces Wnt target genes in tumor and endothelial cells. Our results implicate DKK1 downregulation as an important mechanism underlying TNC-enhanced tumor progression through the provision of a proangiogenic tumor microenvironment.
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Efemp1 and p27(Kip1) modulate responsiveness of pancreatic cancer cells towards a dual PI3K/mTOR inhibitor in preclinical models.
Oncotarget
PUBLISHED: 03-09-2013
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Pancreatic ductal adenocarcinoma (PDAC) remains a dismal disease with a poor prognosis and targeted therapies have failed in the clinic so far. Several evidences point to the phosphatidylinositol 3-kinase (PI3K)-mTOR pathway as a promising signaling node for targeted therapeutic intervention. Markers, which predict responsiveness of PDAC cells towards PI3K inhibitors are unknown. However, such markers are needed and critical to better stratify patients in clinical trials. We used a large murine Kras(G12D)- and PI3K (p110?(H1047R))-driven PDAC cell line platform to unbiased define modulators of responsiveness towards the dual PI3K-mTOR inhibitor Bez235. In contrast to other tumor models, we show that Kras(G12D)- and PI3K (p110?(H1047R))-driven PDAC cell lines are equally sensitive towards Bez235. In an unbiased approach we found that the extracellular matrix protein Efemp1 controls sensitivity of murine PDAC cells towards Bez235. We show that Efemp1 expression is connected to the cyclin-dependent kinase inhibitor p27(Kip1). In a murine Kras(G12D)-driven PDAC model, p27(Kip1) haploinsufficiency accelerates cancer development in vivo. Furthermore, p27(Kip1) controls Bez235 sensitivity in a gene dose-dependent fashion in murine PDAC cells and lowering of p27(Kip1) decreases Bez235 responsiveness in murine PDAC models. Together, we define the Efemp1-p27(Kip1) axis as a potential marker module of PDAC cell sensitivity towards dual PI3K-mTOR inhibitors, which might help to better stratify patients in clinical trials.
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Intraductal papillary neoplasms of the bile duct: stepwise progression to carcinoma involves common molecular pathways.
Mod. Pathol.
PUBLISHED: 02-14-2013
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Intraductal papillary neoplasms of the bile duct are still poorly characterized regarding (1) their molecular alterations during the development to invasive carcinomas, (2) their subtype stratification and (3) their biological behavior. We performed a multicenter study that analyzed these issues in a large European cohort. Intraductal papillary neoplasms of the bile duct from 45 patients were graded and subtyped using mucin markers and CDX2. In addition, tumors were analyzed for common oncogenic pathways, and the findings were correlated with subtype and grade. Data were compared with those from 22 extra- and intrahepatic cholangiocarcinomas. Intraductal papillary neoplasms showed a development from preinvasive low- to high-grade intraepithelial neoplasia to invasive carcinoma. Molecular and immunohistochemical analysis revealed mutated KRAS, overexpression of TP53 and loss of p16 in low-grade intraepithelial neoplasia, whereas loss of SMAD4 was found in late phases of tumor development. Alterations of HER2, EGFR, ?-catenin and GNAS were rare events. Among the subtypes, pancreato-biliary (36%) and intestinal (29%) were the most common, followed by gastric (18%) and oncocytic (13%) subtypes. Patients with intraductal papillary neoplasm of the bile duct showed a slightly better overall survival than patients with cholangiocarcinoma (hazard ratio (cholangiocarcinoma versus intraductal papillary neoplasm of the bile duct): 1.40; 95% confidence interval: 0.46-4.30; P=0.552). The development of biliary intraductal papillary neoplasms of the bile duct follows an adenoma-carcinoma sequence that correlates with the stepwise activation of common oncogenic pathways. Further large trials are needed to investigate and verify the finding of a better prognosis of intraductal papillary neoplasms compared with conventional cholangiocarcinoma.
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Selective requirement of PI3K/PDK1 signaling for Kras oncogene-driven pancreatic cell plasticity and cancer.
Cancer Cell
PUBLISHED: 01-30-2013
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Oncogenic Kras activates a plethora of signaling pathways, but our understanding of critical Ras effectors is still very limited. We show that cell-autonomous phosphoinositide 3-kinase (PI3K) and 3-phosphoinositide-dependent protein kinase 1 (PDK1), but not Craf, are key effectors of oncogenic Kras in the pancreas, mediating cell plasticity, acinar-to-ductal metaplasia (ADM), and pancreatic ductal adenocarcinoma (PDAC) formation. This contrasts with Kras-driven non-small cell lung cancer, where signaling via Craf, but not PDK1, is an essential tumor-initiating event. These in vivo genetic studies together with pharmacologic treatment studies in models of human ADM and PDAC demonstrate tissue-specific differences of oncogenic Kras signaling and define PI3K/PDK1 as a suitable target for therapeutic intervention specifically in PDAC.
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G-Protein coupled receptor 64 promotes invasiveness and metastasis in Ewing sarcomas through PGF and MMP1.
J. Pathol.
PUBLISHED: 01-09-2013
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Metastatic spread in Ewing sarcomas (ES) is frequent and haematogenous. G-protein coupled receptor 64 (GPR64), an orphan receptor with normal expression restricted to human epididymis is specifically over-expressed in ES among sarcoma, but also up-regulated in a number of carcinomas derived from prostate, kidney or lung. Inhibition of GPR64 expression in ES by RNA interference impaired colony formation in vitro and suppressed local tumour growth and metastasis in Rag2(-/-) ?C (-/-) mice. Microarray analysis after GPR64 knock down revealed a GPR64-mediated repression of genes involved in neuronal development like SLIT, drosophila, homolog of, 2 (SLIT2), and genes regulating transcription including pre-B cell leukemia homeobox 2 (PBX2). Concurrently, the suppression of GPR64 increased ES susceptibility to TRAIL induced apoptosis. Moreover, a GPR64-mediated induction of placental growth factor (PGF) in ES was observed. PGF suppression by RNA interference resulted in a reduction of metastatic growth similar to that observed after GPR64 knock down. Importantly, inhibition of GPR64 as well as PGF expression was associated with a reduced expression of matrix metalloproteinase (MMP) 1 and invasiveness in vitro. Furthermore, MMP1 knock down abrogated lung metastasis in Rag2(-/-) ?C (-/-) mice. Thus, GPR64 expression in ES maintains an immature phenotype that is less sensitive to TRAIL-induced apoptosis and via its up-regulation of PGF and MMP1 orchestrates and promotes invasiveness and metastatic spread.
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STEAP1 is associated with the invasive and oxidative stress phenotype of Ewing tumors.
Mol. Cancer Res.
PUBLISHED: 11-11-2011
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Ewing tumors comprise the second most common type of bone-associated cancer in children and are characterized by oncogenic EWS/FLI1 fusion proteins and early metastasis. Compelling evidence suggests that elevated levels of intracellular oxidative stress contribute to enhanced aggressiveness of numerous cancers, possibly including Ewing tumors. Using comprehensive microarray analyses and RNA interference, we identified the six-transmembrane epithelial antigen of the prostate 1 (STEAP1)-a membrane-bound mesenchymal stem cell marker of unknown function-as a highly expressed protein in Ewing tumors compared with benign tissues and show its regulation by EWS/FLI1. In addition, we show that STEAP1 knockdown reduces Ewing tumor proliferation, anchorage-independent colony formation as well as invasion in vitro and decreases growth and metastasis of Ewing tumor xenografts in vivo. Moreover, transcriptome and proteome analyses as well as functional studies revealed that STEAP1 expression correlates with oxidative stress responses and elevated levels of reactive oxygen species that in turn are able to regulate redox-sensitive and proinvasive genes. In synopsis, our data suggest that STEAP1 is associated with the invasive behavior and oxidative stress phenotype of Ewing tumors and point to a hitherto unanticipated oncogenic function of STEAP1.
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Spinal muscular atrophy type 1: avoidance of hospitalization by respiratory muscle support.
Am J Phys Med Rehabil
PUBLISHED: 09-30-2011
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The aim of this study was to report the outcomes of an oximetry protocol using up to continuous full ventilator-setting noninvasive ventilation (NIV) and mechanically assisted coughing (MAC) to avoid episodes of acute respiratory failure and hospitalizations for children with spinal muscular atrophy type 1 under 3 yrs of age.
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Glutamate increases pancreatic cancer cell invasion and migration via AMPA receptor activation and Kras-MAPK signaling.
Int. J. Cancer
PUBLISHED: 08-01-2011
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Glutamate has been implicated in tumorigenesis through activation of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPAR). However, the function of a glutamate-to-AMPAR signal in pancreatic ductal adenocarcinoma (PDAC) has remained elusive. We now show that glutamate-mediated AMPA receptor activation increases invasion and migration of pancreatic cancer cells via activation of the classical MAPK pathway. Glutamate levels were increased in pancreatic cancer accompanied by downregulation of GluR subunits 1, 2, and 4. In pancreatic cancer precursor lesions, pancreatic intraepithelial neoplasia (PanIN), GluR1 subunit levels were strikingly and step-wise increased but its expression was rare in PDAC. Pharmacological inhibition or RNAi-mediated suppression of GluR1 or GluR2 did not affect cancer cell growth but significantly decreased invasion. In a K-ras wildtype cell line, AMPA receptor activation enhanced K-ras activity and--further downstream--phosphorylation of p38 and of p44/42. Preemptive blockade of AMPA receptors in a mouse model of pancreatic cancer inhibited tumor cell settling. AMPA receptor activation thus not only activates MAPK signalling but also directly increases activity of K-ras. Glutamate might serve as a molecular switch that decreases the threshold of K-ras-induced oncogenic signalling and increases the chance of malignant transformation of pancreatic cancer precursor lesions.
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Toxicity modelling of Plk1-targeted therapies in genetically engineered mice and cultured primary mammalian cells.
Nat Commun
PUBLISHED: 06-16-2011
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High attrition rates of novel anti-cancer drugs highlight the need for improved models to predict toxicity. Although polo-like kinase 1 (Plk1) inhibitors are attractive candidates for drug development, the role of Plk1 in primary cells remains widely unexplored. Therefore, we evaluated the utility of an RNA interference-based model to assess responses to an inducible knockdown (iKD) of Plk1 in adult mice. Here we show that Plk1 silencing can be achieved in several organs, although adverse events are rare. We compared responses in Plk1-iKD mice with those in primary cells kept under controlled culture conditions. In contrast to the addiction of many cancer cell lines to the non-oncogene Plk1, the primary cells proliferation, spindle assembly and apoptosis exhibit only a low dependency on Plk1. Responses to Plk1-depletion, both in cultured primary cells and in our iKD-mouse model, correspond well and thus provide the basis for using validated iKD mice in predicting responses to therapeutic interventions.
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Tenascin-C enhances pancreatic cancer cell growth and motility and affects cell adhesion through activation of the integrin pathway.
PLoS ONE
PUBLISHED: 06-08-2011
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Pancreatic cancer (PDAC) is characterized by an abundant fibrous tissue rich in Tenascin-C (TNC), a large ECM glycoprotein mainly synthesized by pancreatic stellate cells (PSCs). In human pancreatic tissues, TNC expression increases in the progression from low-grade precursor lesions to invasive cancer. Aim of this study was the functional characterization of the effects of TNC on biologic relevant properties of pancreatic cancer cells.
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In vivo diagnosis of murine pancreatic intraepithelial neoplasia and early-stage pancreatic cancer by molecular imaging.
Proc. Natl. Acad. Sci. U.S.A.
PUBLISHED: 05-31-2011
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Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with poor patient outcome often resulting from late diagnosis in advanced stages. To date methods to diagnose early-stage PDAC are limited and in vivo detection of pancreatic intraepithelial neoplasia (PanIN), a preinvasive precursor of PDAC, is impossible. Using a cathepsin-activatable near-infrared probe in combination with flexible confocal fluorescence lasermicroscopy (CFL) in a genetically defined mouse model of PDAC we were able to detect and grade murine PanIN lesions in real time in vivo. Our diagnostic approach is highly sensitive and specific and proved superior to clinically established fluorescein-enhanced imaging. Translation of this endoscopic technique into the clinic should tremendously improve detection of pancreatic neoplasia, thus reforming management of patients at risk for PDAC.
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Preoperative radiological characterization of hepatic angiomyolipoma using magnetic resonance imaging and contrast-enhanced ultrasonography: a case report.
J Med Case Rep
PUBLISHED: 05-20-2011
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A hepatic angiomyolipoma is a rare benign tumor of the liver composed of a mixture of smooth muscle cells, blood vessels and a variable amount of adipose tissue. Differentiating them from malignant liver tumors can often be very difficult.
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5 Triphosphorylated small interfering RNAs control replication of hepatitis B virus and induce an interferon response in human liver cells and mice.
Gastroenterology
PUBLISHED: 04-26-2011
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Approved therapies for chronic hepatitis B include systemic administration of interferon (IFN)-alfa and inhibitors of hepatitis B virus (HBV) reverse-transcription. Systemic application of IFN-alfa is limited by side effects. Reverse-transcriptase inhibitors effectively control HBV replication, but rarely eliminate the virus and can select drug-resistant variants. We aimed to develop an alternative therapeutic approach that combines gene silencing with induction of IFN in the liver.
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Autoimmune pancreatitis complicated by carcinoma of the pancreatobiliary system: a case report and review of the literature.
Pancreas
PUBLISHED: 04-19-2011
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We present the case of a 67-year-old woman who developed a metastatic adenocarcinoma of the pancreatobiliary system shortly after the histologically confirmed diagnosis of autoimmune pancreatitis (AIP). This case highlights the need for increased alertness not only in differentiating AIP from pancreatic cancer at the time of diagnosis, but also to exclude concomitant malignancies of the pancreatobiliary system in the management of histologically confirmed AIP.
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Requirement of the RNA-editing enzyme ADAR2 for normal physiology in mice.
J. Biol. Chem.
PUBLISHED: 04-05-2011
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ADAR2, an RNA editing enzyme that converts specific adenosines to inosines in certain pre-mRNAs, often leading to amino acid substitutions in the encoded proteins, is mainly expressed in brain. Of all ADAR2-mediated edits, a single one in the pre-mRNA of the AMPA receptor subunit GluA2 is essential for survival. Hence, early postnatal death of mice lacking ADAR2 is averted when the critical edit is engineered into both GluA2 encoding Gria2 alleles. Adar2(-/-)/Gria2(R/R) mice display normal appearance and life span, but the general phenotypic effects of global lack of ADAR2 have remained unexplored. Here we have employed the Adar2(-/-)/Gria2(R/R) mouse line, and Gria2(R/R) mice as controls, to study the phenotypic consequences of loss of all ADAR2-mediated edits except the critical one in GluA2. Our extended phenotypic analysis covering ?320 parameters identified significant changes related to absence of ADAR2 in behavior, hearing ability, allergy parameters and transcript profiles of brain.
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Missing-in-metastasis MIM/MTSS1 promotes actin assembly at intercellular junctions and is required for integrity of kidney epithelia.
J. Cell. Sci.
PUBLISHED: 03-15-2011
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MIM/MTSS1 is a tissue-specific regulator of plasma membrane dynamics, whose altered expression levels have been linked to cancer metastasis. MIM deforms phosphoinositide-rich membranes through its I-BAR domain and interacts with actin monomers through its WH2 domain. Recent work proposed that MIM also potentiates Sonic hedgehog (Shh)-induced gene expression. Here, we generated MIM mutant mice and found that full-length MIM protein is dispensable for embryonic development. However, MIM-deficient mice displayed a severe urinary concentration defect caused by compromised integrity of kidney epithelia intercellular junctions, which led to bone abnormalities and end-stage renal failure. In cultured kidney epithelial (MDCK) cells, MIM displayed dynamic localization to adherens junctions, where it promoted Arp2/3-mediated actin filament assembly. This activity was dependent on the ability of MIM to interact with both membranes and actin monomers. Furthermore, results from the mouse model and cell culture experiments suggest that full-length MIM is not crucial for Shh signaling, at least during embryogenesis. Collectively, these data demonstrate that MIM modulates interplay between the actin cytoskeleton and plasma membrane to promote the maintenance of intercellular contacts in kidney epithelia.
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A novel N-ethyl-N-nitrosourea-induced mutation in phospholipase C?2 causes inflammatory arthritis, metabolic defects, and male infertility in vitro in a murine model.
Arthritis Rheum.
PUBLISHED: 02-10-2011
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It is difficult to identify a single causative factor for inflammatory arthritis because of the multifactorial nature of the disease. This study was undertaken to dissect the molecular complexity of systemic inflammatory disease, utilizing a combined approach of mutagenesis and systematic phenotype screening in a murine model.
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Pigment epithelium-derived factor associates with neuropathy and fibrosis in pancreatic cancer.
Am. J. Gastroenterol.
PUBLISHED: 01-11-2011
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Pigment epithelium-derived factor (PEDF) is a noninhibitory member of the serine protease inhibitor gene family with neuroprotective, neuroproliferative, and anti-angiogenic functions. Its role in pancreatic fibrosis and neuropathy is unknown.
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Validation of preclinical multiparametric imaging for prediction of necrosis in hepatocellular carcinoma after embolization.
J. Hepatol.
PUBLISHED: 01-10-2011
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The hepatocellular carcinoma (HCC) exhibits varying degrees of vascularization with more poorly differentiated carcinoma commonly exhibiting high amounts of vascularization. Transcatheter arterial embolization (TAE) of HCC tumor nodules results in varying amounts of tumor necrosis. Reliable quantification of necrosis after TAE, would aid in treatment planning and testing of novel combinatorial treatment regimen. The aim of this work was to validate different imaging parameters as individual or combined predictors of tumor necrosis after TAE in an orthotopic rat HCC tumor model.
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A novel method of forceps biopsy improves the diagnosis of proximal biliary malignancies.
Dig. Dis. Sci.
PUBLISHED: 01-08-2011
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Tissue specimen collection represents a cornerstone in diagnosis of proximal biliary tract malignancies offering great specificity, but only limited sensitivity. To improve the tumor detection rate, we developed a new method of forceps biopsy and compared it prospectively with endoscopic transpapillary brush cytology.
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Liver mitochondrial membrane crosslinking and destruction in a rat model of Wilson disease.
J. Clin. Invest.
PUBLISHED: 01-05-2011
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Wilson disease (WD) is a rare hereditary condition that is caused by a genetic defect in the copper-transporting ATPase ATP7B that results in hepatic copper accumulation and lethal liver failure. The present study focuses on the structural mitochondrial alterations that precede clinical symptoms in the livers of rats lacking Atp7b, an animal model for WD. Liver mitochondria from these Atp7b–/– rats contained enlarged cristae and widened intermembrane spaces, which coincided with a massive mitochondrial accumulation of copper. These changes, however, preceded detectable deficits in oxidative phosphorylation and biochemical signs of oxidative damage, suggesting that the ultrastructural modifications were not the result of oxidative stress imposed by copper- dependent Fenton chemistry. In a cell-free system containing a reducing dithiol agent, isolated mitochondria exposed to copper underwent modifications that were closely related to those observed in vivo. In this cell-free system, copper induced thiol modifications of three abundant mitochondrial membrane proteins, and this correlated with reversible intramitochondrial membrane crosslinking, which was also observed in liver mitochondria from Atp7b–/– rats. In vivo, copper-chelating agents reversed mitochondrial accumulation of copper, as well as signs of intra-mitochondrial membrane crosslinking, thereby preserving the functional and structural integrity of mitochondria. Together, these findings suggest that the mitochondrion constitutes a pivotal target of copper in WD.
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Two pediatric cases of multidrug-resistant tuberculosis treated with linezolid and moxifloxacin.
Pediatrics
PUBLISHED: 10-25-2010
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We report here 2 pediatric cases of multidrug-resistant (MDR) tuberculosis (TB) that were observed in Italy. Both families came from an Eastern European country, which is notably an area with a high prevalence of MDR TB. An increase of new cases of MDR TB in developed countries is expected over the next years because of migratory flow, and specific measures and strategies need to be taken to prevent the propagation and dissemination of MDR TB. An efficacious treatment including linezolid and moxifloxacin was administered for 13 months in 1 case. No adverse reactions were detected during close child monitoring. Linezolid and newer fluoroquinolones such as moxifloxacin have been reported to be effective for MDR-TB treatment in adults. On the contrary, there is limited available evidence regarding the effectiveness and safety of these drugs in infants and children with MDR TB. The use of second-line drugs not approved for use in children may be necessary to treat a life-threatening disease such as MDR TB, but it requires careful monitoring to quickly recognize the occurrence of dose- and duration-dependent adverse drug reactions.
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Reduced expression of the membrane skeleton protein beta1-spectrin (SPTBN1) is associated with worsened prognosis in pancreatic cancer.
Histol. Histopathol.
PUBLISHED: 10-02-2010
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Spectrins are members of the superfamily of F-actin cross linking proteins that are important as scaffolding proteins for protein sorting, cell adhesion, and migration. In addition, spectrins have been implicated in TGF-beta signaling. The aim of the present study was to analyze the expression and localization of beta1-spectrin (SPTBN1) in pancreatic tissues. mRNA levels of SPTBN1 in cultured pancreatic cancer cell lines, as well as in normal pancreatic tissues (n=18), chronic pancreatitis (n=48) and pancreatic cancer tissues (n=66) were analyzed by real time quantitative RT-PCR. Localization of SPTBN1 in pancreatic tissues was determined by immunohistochemistry. SPTBN1 staining was assessed semi-quantitatively in 55 cancer tissues and survival analysis was carried out using the Kaplan-Meier method. Median SPTBN1 mRNA levels were 6.0-fold higher in pancreatic cancer tissues compared to the normal pancreas (p<0.0001) and 2.2-fold higher compared to chronic pancreatitis tissues (p=0.0002). In the normal pancreas, SPTBN1 was present in the cytoplasm of normal ductal cells and occasionally in pancreatic acinar and centroacinar cells. In pancreatic cancer tissues, SPTBN1 was present in the cytoplasm of pancreatic cancer cells. Low SPTBN1 protein expression indicated a tendency for worsened prognosis with a median survival of 14.0 months, versus 23.8 months for patients whose tumors expressed moderate/high levels of SPTBN1. In conclusion, reduced SPTBN1 expression correlated with shorter survival of pancreatic cancer patients, suggesting a tumor suppressor function of this gene, as has already been shown for other malignancies of the gastrointestinal tract.
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Expression of L1CAM, COX-2, EGFR, c-KIT and Her2/neu in anaplastic pancreatic cancer: putative therapeutic targets?
Histopathology
PUBLISHED: 05-13-2010
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Undifferentiated (anaplastic) pancreatic cancer and undifferentiated pancreatic carcinoma with osteoclast-like giant cells (giant cell tumour) are rare variants of pancreatic ductal adenocarcinoma. Representing biologically highly aggressive neoplasms, they are frequently diagnosed at an advanced stage. The response to established chemo- or radiochemotherapeutic treatment regimens is poor, and undifferentiated pancreatic cancer generally has a dismal prognosis. As additional therapeutic options have not yet been investigated in undifferentiated pancreatic cancer, the aim was to analyse the expression of putative therapeutic targets that have shown promising results in various other neoplasms.
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Mouse phenotyping.
Methods
PUBLISHED: 03-30-2010
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Model organisms like the mouse are important tools to learn more about gene function in man. Within the last 20 years many mutant mouse lines have been generated by different methods such as ENU mutagenesis, constitutive and conditional knock-out approaches, knock-down, introduction of human genes, and knock-in techniques, thus creating models which mimic human conditions. Due to pleiotropic effects, one gene may have different functions in different organ systems or time points during development. Therefore mutant mouse lines have to be phenotyped comprehensively in a highly standardized manner to enable the detection of phenotypes which might otherwise remain hidden. The German Mouse Clinic (GMC) has been established at the Helmholtz Zentrum München as a phenotyping platform with open access to the scientific community (www.mousclinic.de; [1]). The GMC is a member of the EUMODIC consortium which created the European standard workflow EMPReSSslim for the systemic phenotyping of mouse models (http://www.eumodic.org/[2]).
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Differential effects of genes of the Rb1 signalling pathway on osteosarcoma incidence and latency in alpha-particle irradiated mice.
Radiat Environ Biophys
PUBLISHED: 02-01-2010
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Osteosarcoma is the most frequent secondary malignancy following radiotherapy of patients with bilateral retinoblastoma. This suggests that the Rb1 tumour suppressor gene might confer genetic susceptibility towards radiation-induced osteosarcoma. To define the contribution of the Rb1 pathway in the multistep process of radiation carcinogenesis, we evaluated somatic allelic changes affecting the Rb1 gene itself as well as its upstream regulator p16 in murine osteosarcoma induced by (227)Th incorporation. To distinguish between the contribution of germline predisposition and the effect of a 2-hit allelic loss, two mouse models harbouring heterozygote germline Rb1 and p16 defects were tested for the incidence and latency of osteosarcoma following irradiation. We could show that all tumours arising in BALB/c×CBA/CA hybrid mice (wild-type for Rb1 and for p16) carried a somatic allelic loss of either the Rb1 gene (76.5%) or the p16 gene (59%). In none of the tumours, we found concordant retention of heterozygosity at both loci. Heterozygote knock-out mice for Rb1 exhibit a significant increase in the incidence of osteosarcoma following (227)Th incorporation (11/24 [corrected] in Rb1+/- vs. 2/18 in Rb1+/+, p=4×10(-5)), without affecting tumour latency. In contrast, heterozygote knock-out mice for p16 had no significant change in tumour incidence, but a pronounced reduction of latency (LT(50%) =355 days in p16+/- vs. 445 days in p16+/+, p=8×10(-3)). These data suggest that Rb1 germline defects influence early steps of radiation osteosarcomagenesis, whereas alterations in p16 mainly affect later stages of tumour promotion and growth.
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Microphthalmia, parkinsonism, and enhanced nociception in Pitx3 ( 416insG ) mice.
Mamm. Genome
PUBLISHED: 08-24-2009
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A new spontaneous mouse mutant was characterized by closed eyelids at weaning and without apparent eyes (provisional gene name, eyeless; provisional gene symbol, eyl). The mutation follows a recessive pattern of inheritance and was mapped to the region of chromosome 19 containing Pitx3. Genetic complementation tests using Pitx3 ( ak/+ ) mice confirmed eyl as a new allele of Pitx3 (Pitx3 ( eyl )). Sequencing of the Pitx3 gene in eyl mutants identified an inserted G after cDNA position 416 (416insG; exon 4). The shifted open reading frame is predicted to result in a hybrid protein still containing the Pitx3 homeobox, but followed by 121 new amino acids. The novel Pitx3 ( eyl/eyl ) mutants expressed ophthalmological and brain defects similar to Pitx3 ( ak/ak ) mice: microphthalmia or anophthalmia and loss of dopamine neurons of the substantia nigra. In addition, we observed in the homozygous eyeless mutants increased extramedullary hematopoiesis in the spleen, frequently liver steatosis, and reduced body weight. There were also several behavioral changes in the homozygous mutants, including reduced forelimb grip strength and increased nociception. In addition to these alterations in both sexes, we observed in female Pitx3 ( eyl/eyl ) mice increased anxiety-related behavior, reduced locomotor activity, reduced object exploration, and increased social contacts; however, we observed decreased anxiety-related behavior and increased arousal in males. Most of these defects identified in the new Pitx3 mutation are observed in Parkinson patients, making the Pitx3 ( eyl ) mutant a valuable new model. It is the first mouse mutant carrying a point mutation within the coding region of Pitx3.
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Glucagon/insulin ratio as a potential biomarker for pancreatic cancer in patients with new-onset diabetes mellitus.
Cancer Biol. Ther.
PUBLISHED: 08-13-2009
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Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive malignancies, with an overall 5-year survival rate of less than 5%. This dismal prognosis is largely due to the advanced stage of the disease at presentation, i.e., the late diagnosis. Therefore, early detection would have the potential to significantly improve the overall prognosis of PDAC patients. Diabetes mellitus (DM) has a high prevalence in PDAC patients and is frequently of new onset. The aim of this study was to analyze whether DM can be utilized as an early disease marker in PDAC. Quantitative RT-PCR analysis and immunohistochemistry for insulin and glucagon was performed in 22 PDAC and 16 normal pancreas tissues. Blood samples of 66 patients suffering from PDAC, 35 DM type 2 patients, and 29 healthy donors were analyzed for insulin, glucagon, C-peptide and glucose levels. Quantitative RT-PCR showed a two-fold increase of the glucagon/insulin ratio in pancreatic cancer tissues in comparison to the normal pancreas. By immunohistochemistry a shift in the expression pattern of glucagon and insulin, i.e., a higher glucagon/insulin ratio was found in PDAC associated islets compared to islets in the normal pancreas. Fasting insulin levels in PDAC patients were lower compared to DM patients. The calculated serum glucagon/insulin ratio was significantly different between PDAC and DM patients. At a cut-off of 7.4 ng/mU glucagon/insulin, pancreatic cancer induced new-onset DM could be discriminated from type 2 DM with 77% sensitivity and 69% specificity. In conclusion, the suggested serum glucagon/insulin ratio showed significant differences in patients with PDAC related DM and type 2 DM. Therefore, this analysis might help to identify PDAC in patients with new-onset DM in the age group at risk. Larger clinical trials have to confirm these findings.
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Expression of the costimulatory molecule B7-H3 is associated with prolonged survival in human pancreatic cancer.
BMC Cancer
PUBLISHED: 07-26-2009
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Costimulatory signaling has been implicated as a potential regulator of antitumor immunity in various human cancers. In contrast to the negative prognostic value of aberrant B7-H1 expression by pancreatic cancer cells, the role of B7-H3 is still unknown. Therefore, we investigated the expression pattern and clinical significance of B7-H3 expression in human pancreatic cancer.
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Identification of malignancy factors by analyzing cystic tumors of the pancreas.
Pancreatology
PUBLISHED: 07-18-2009
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The diversity in the aggressiveness of cystic tumors of the pancreas - ranging from the usually benign serous cystadenoma to lesions of variable degrees of malignancy - was utilized for the identification of molecular factors that are involved in the occurrence of malignancy.
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Consensus transcriptome signature of perineural invasion in pancreatic carcinoma.
Mol. Cancer Ther.
PUBLISHED: 06-09-2009
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Perineural invasion, the growth of tumor cells along nerves, is a key feature of pancreatic cancer. The cardinal symptom of pancreatic cancer, abdominal pain often radiating to the back, as well as the high frequency of local tumor recurrence following resection are both attributed to the unique ability of pancreatic tumor cells to invade the neuronal system. The molecular mechanisms underlying the neuroaffinity of pancreatic tumors are not completely understood. In this study, we developed a novel method to monitor ex vivo perineural invasion into surgically resected rat vagal nerves by different human pancreatic tumor cell lines. Genome-wide transcriptional analyses were employed to identify the consensus set of genes differentially regulated in all highly nerve-invasive (nerve invasion passage 3) versus less invasive (nerve invasion passage 0) pancreatic tumor cells. The critical involvement of kinesin family member 14 (KIF14) and Rho-GDP dissociation inhibitor beta (ARHGDIbeta) in perineural invasion was confirmed on RNA and protein levels in human pancreatic tumor specimens. We found significant up-regulation of KIF14 and ARHGDIbeta mRNA levels in patients with pancreatic cancer, and both proteins were differentially expressed in tumor cells invading the perineural niche of pancreatic cancer patients as detected by immunohistochemistry. Moreover, functional knockdown of KIF14 and ARHGDIbeta using small interfering RNA resulted in altered basal and/or perineural invasion of pancreatic tumor cells. Our work provides novel insights into the molecular determinants of perineural invasion in pancreatic cancer. The established nerve invasion model and the consensus signature of perineural invasion could be instrumental in the identification of novel therapeutic targets of pancreatic cancer as exemplified by KIF14 and ARHGDIbeta.
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Identification of differentially expressed proteins in triple-negative breast carcinomas using DIGE and mass spectrometry.
J. Proteome Res.
PUBLISHED: 06-03-2009
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We compared the protein expression pattern of triple-negative breast carcinomas (HER2-, ER-, PR-) versus those being positive for HER2 and negative for the hormone receptors (HER2+, ER-, PR-) by 2-D DIGE and mass spectrometry. We obtained differential expression patterns for several glycolytic enzymes (as for example MDH2, PGK1, TKT, Aldolase1), cytokeratins (CK7, 8, 9, 14, 17, 19), further structure proteins (vimentin, fibronectin, L-plastin), for NME1-NME2, lactoferrin, and members of the Annexin family. Western blot analysis and immunohistochemistry were conducted to verify the results. The identified marker proteins may advance a more detailed characterization of triple-negative breast cancers and may contribute to the development of better treatment strategies.
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Evaluation of alphavbeta3 integrin-targeted positron emission tomography tracer 18F-galacto-RGD for imaging of vascular inflammation in atherosclerotic mice.
Circ Cardiovasc Imaging
PUBLISHED: 05-13-2009
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(18)F-Galacto-RGD is a positron emission tomography (PET) tracer binding to alpha(v)beta(3) integrin that is expressed by macrophages and endothelial cells in atherosclerotic lesions. Therefore, we evaluated (18)F-galacto-RGD for imaging vascular inflammation by studying its uptake into atherosclerotic lesions of hypercholesterolemic mice in comparison to deoxyglucose.
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Moesin-dependent cytoskeleton remodelling is associated with an anaplastic phenotype of pancreatic cancer.
J. Cell. Mol. Med.
PUBLISHED: 05-11-2009
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Cell motility is controlled by the dynamic cytoskeleton and its related proteins, such as members of the ezrin/radixin/moesin (ERM) family, which act as signalling molecules inducing cytoskeleton remodelling. Although ERM proteins have been identified as important factors in various malignancies, functional redundancy between these proteins has hindered the dissection of their individual contribution. The aim of the present study was to analyse the functional role of moesin in pancreatic malignancies. Cancer cells of different malignant lesions of human and transgenic mice pancreata were evaluated by immunohistochemistry. For functional analysis, cell growth, adhesion and invasion assays were carried out after transient and stable knock-down of moesin expression in pancreatic cancer cells. In vivo tumourigenicity was determined using orthotopic and metastatic mouse tumour models. We now show that moesin knock-down increases migration, invasion and metastasis and influences extracellular matrix organization of pancreatic cancer. Moesin-regulated migratory activities of pancreatic cancer cells were in part promoted through cellular translocation of beta-catenin, and re-distribution and organization of the cytoskeleton. Analysis of human and different transgenic mouse pancreatic cancers demonstrated that moesin is a phenotypic marker for anaplastic carcinoma, suggesting that this ERM protein plays a specific role in pancreatic carcinogenesis.
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Secreted frizzled-related protein 1 extrinsically regulates cycling activity and maintenance of hematopoietic stem cells.
Cell Stem Cell
PUBLISHED: 03-09-2009
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Secreted frizzled-related protein 1 (Sfrp1) is highly expressed by stromal cells maintaining hematopoietic stem cells (HSCs). Sfrp1 loss in stromal cells increases production of hematopoietic progenitors, and in knockout mice, dysregulates hemostasis and increases Flk2- Cd34- Lin- Sca1+ Kit+ (LSK) cell numbers in bone marrow. Also, LSK and multipotent progenitors (MPPs) resided mainly in the G0/G1 phase of cell cycle, with an accompanying decrease in intracellular beta-catenin levels. Gene-expression studies showed a concomitant decrease Ccnd1 and Dkk1 in Cd34- LSK cells and increased expression of Pparg, Hes1, and Runx1 in MPP. Transplantation experiments showed no intrinsic effect of Sfrp1 loss on the number of HSCs or their ability to engraft irradiated recipients. In contrast, serial transplantations of wild-type HSCs into Sfrp1(-/-) mice show a progressive decrease of wild-type LSK and MPP numbers. Our results demonstrate that Sfrp1 is required to maintain HSC homeostasis through extrinsic regulation of beta-catenin.
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Impaired islet turnover in human donor pancreata with aging.
Eur. J. Endocrinol.
PUBLISHED: 03-05-2009
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The prevalence of type 2 diabetes mellitus escalates with aging although beta-cell mass, a primary parameter of beta-cell function, is subject to compensatory regulation. So far it is unclear whether the proliferative capacity of pancreatic islets is restricted by senescence.
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Expression pattern and functional relevance of epidermal growth factor receptor and cyclooxygenase-2: novel chemotherapeutic targets in pancreatic endocrine tumors?
Am. J. Gastroenterol.
PUBLISHED: 02-25-2009
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Pancreatic endocrine tumors represent morphologically and biologically heterogeneous neoplasms. Well-differentiated endocrine tumors (benign or of uncertain behavior) can be distinguished from well-differentiated and poorly differentiated endocrine carcinomas. Although many well-differentiated endocrine carcinomas show rather low rates of tumor growth, more than two-thirds of pancreatic endocrine carcinomas display distant metastases at the time of diagnosis. As the currently applied therapies beyond surgery only achieve partial or complete response rates of approximately 15%, additional chemotherapeutic targets are needed, especially in the therapy of inoperable and progressive pancreatic endocrine carcinomas.
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Cancer-stellate cell interactions perpetuate the hypoxia-fibrosis cycle in pancreatic ductal adenocarcinoma.
Neoplasia
PUBLISHED: 01-27-2009
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Although both cancer and stellate cells (PSCs) secrete proangiogenic factors, pancreatic cancer is a scirrhous and hypoxic tumor. The impact of cancer-PSCs interactions on angiogenesis was analyzed.
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Fundamental differences in the neural invasion behavior of pancreatic endocrine tumors: relevance for local recurrence rates?
Hum. Pathol.
PUBLISHED: 01-07-2009
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Neural invasion represents an important prognostic factor in pancreatic cancer, and it is thought to be one of the main causes for the high rate of postoperative local recurrences in pancreatic ductal adenocarcinomas. In contrast to the latter, systematic investigations of the mode and extent of neural invasion in pancreatic endocrine tumors have not yet been carried out, although this process represents an important feature in the classification of these tumors. In the present study, a total of 48 pancreatic endocrine tumors were analyzed including 10 well-differentiated endocrine tumors of uncertain behavior, 33 well-differentiated endocrine carcinomas, and 5 poorly differentiated endocrine carcinomas. Neural invasion was found in a large subset (73%) of pancreatic endocrine tumors. The frequency of neural invasion correlated with the grade of malignancy but occurred irrespective of functional activity, hormone phenotype, or histomorphology. Analogous to pancreatic ductal adenocarcinoma, the expression of epidermal growth factor receptor and nerve growth factor, which were expressed in 50% and 100% of the tumors, respectively, seemed to be associated with the frequency of neural invasion. However, in contrast to pancreatic ductal adenocarcinoma, neural invasion in pancreatic endocrine tumors was only detected within the tumor boundaries and did not reach beyond the tumor invasion front. This phenomenon may explain the low rate of local relapses after tumor resection in pancreatic endocrine tumors despite the high frequency of neural invasion.
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DKK2 mediates osteolysis, invasiveness, and metastatic spread in Ewing sarcoma.
Cancer Res.
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Ewing sarcoma, an osteolytic malignancy that mainly affects children and young adults, is characterized by early metastasis to lung and bone. In this study, we identified the pro-metastatic gene DKK2 as a highly overexpressed gene in Ewing sarcoma compared with corresponding normal tissues. Using RNA interference, we showed that DKK2 was critical for malignant cell outgrowth in vitro and in an orthotopic xenograft mouse model in vivo. Analysis of invasion potential in both settings revealed a strong correlation of DKK2 expression to Ewing sarcoma invasiveness that may be mediated by the DKK effector matrix metalloproteinase 1 (MMP1). Furthermore, gene expression analyses established the ability of DKK2 to differentially regulate genes such as CXCR4, PTHrP, RUNX2, and TGF?1 that are associated with homing, invasion, and growth of cancer cells in bone tissue as well as genes important for osteolysis, including HIF1?, JAG1, IL6, and VEGF. DKK2 promoted bone infiltration and osteolysis in vivo and further analyses defined DKK2 as a key factor in osteotropic malignancy. Interestingly, in Ewing sarcoma cells, DKK2 suppression simultaneously increased the potential for neuronal differentiation while decreasing chondrogenic and osteogenic differentiation. Our results provide strong evidence that DKK2 is a key player in Ewing sarcoma invasion and osteolysis and also in the differential phenotype of Ewing sarcoma cells.
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Aloxe3 knockout mice reveal a function of epidermal lipoxygenase-3 as hepoxilin synthase and its pivotal role in barrier formation.
J. Invest. Dermatol.
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Loss-of-function mutations in the lipoxygenase (LOX) genes ALOX12B and ALOXE3 are the second most common cause of autosomal recessive congenital ichthyosis. The encoded proteins, 12R-LOX and epidermal LOX-3 (eLOX-3), act in sequence to convert fatty acid substrates via R-hydroperoxides to specific epoxyalcohol derivatives and have been proposed to operate in the same metabolic pathway during epidermal barrier formation. Here, we show that eLOX-3 deficiency in mice results in early postnatal death, associated with similar but somewhat less severe barrier defects and morphological changes than reported earlier for the 12R-LOX-knockout mice. Skin lipid analysis demonstrated that the severity of barrier failure is related to the loss of covalently bound ceramides in both 12R-LOX- and eLOX-3-null mice, confirming a proposed functional linkage of the LOX pathway to ceramide processing and formation of the corneocyte lipid envelope. Furthermore, analysis of free oxygenated fatty acid metabolites revealed strongly reduced levels of hepoxilin metabolites in eLOX-3-deficient epidermis, indicating an additional function of eLOX-3 in mammalian skin as a hepoxilin synthase linked to the 12S-LOX pathway.
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Srgap3?/? mice present a neurodevelopmental disorder with schizophrenia-related intermediate phenotypes.
FASEB J.
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Mutations in the SRGAP3 gene residing on chromosome 3p25 have previously been associated with intellectual disability. Genome-wide association studies have also revealed SRGAP3, together with genes from the same cellular network, as risk genes for schizophrenia. SRGAP3 regulates cytoskeletal dynamics through the RHO protein RAC1. RHO proteins are known to be involved in cytoskeletal reorganization during brain development to control processes such as synaptic plasticity. To elucidate the importance of SRGAP3 in brain development, we generated Srgap3-knockout mice. Ten percent of these mice developed a hydrocephalus and died before adulthood. Surviving mice showed various neuroanatomical changes, including enlarged lateral ventricles, white matter tracts, and dendritic spines together with molecular changes, including an increased basal activity of RAC1. Srgap3(-/-) mice additionally exhibited a complex behavioral phenotype. Behavioral studies revealed an impaired spontaneous alternation and social behavior, while long-term memory was unchanged. The animals also had tics. Lower locomotor activity was observed in male Srgap3(-/-) only. Srgap3(-/-) mice showed increased methylphenidate stimulation in males and an impaired prepulse inhibition in females. Together, the results show neurodevelopmental aberration in Srgap3(-/-) mice, with many of the observed phenotypes matching several schizophrenia-related intermediate phenotypes. Mutations of SRGAP3 may thus contribute to various neurodevelopmental disorders.
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MALDI imaging mass spectrometry for in situ proteomic analysis of preneoplastic lesions in pancreatic cancer.
PLoS ONE
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The identification of new biomarkers for preneoplastic pancreatic lesions (PanINs, IPMNs) and early pancreatic ductal adenocarcinoma (PDAC) is crucial due to the diseases high mortality rate upon late detection. To address this task we used the novel technique of matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) on genetically engineered mouse models (GEM) of pancreatic cancer. Various GEM were analyzed with MALDI IMS to investigate the peptide/protein-expression pattern of precursor lesions in comparison to normal pancreas and PDAC with cellular resolution. Statistical analysis revealed several discriminative m/z-species between normal and diseased tissue. Intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN) could be distinguished from normal pancreatic tissue and PDAC by 26 significant m/z-species. Among these m/z-species, we identified Albumin and Thymosin-beta 4 by liquid chromatography and tandem mass spectrometry (LC-MS/MS), which were further validated by immunohistochemistry, western blot, quantitative RT-PCR and ELISA in both murine and human tissue. Thymosin-beta 4 was found significantly increased in sera of mice with PanIN lesions. Upregulated PanIN expression of Albumin was accompanied by increased expression of liver-restricted genes suggesting a hepatic transdifferentiation program of preneoplastic cells. In conclusion we show that GEM of endogenous PDAC are a suitable model system for MALDI-IMS and subsequent LC-MS/MS analysis, allowing in situ analysis of small precursor lesions and identification of differentially expressed peptides and proteins.
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MondoA is highly overexpressed in acute lymphoblastic leukemia cells and modulates their metabolism, differentiation and survival.
Leuk. Res.
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Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted therapy, we performed a comprehensive transcriptome analysis identifying MondoA (MLXIP) - a transcription factor regulating glycolysis - to be overexpressed in ALL compared to normal tissues. Using microarray-profiling, gene-set enrichment analysis, RNA interference and functional assays we show that MondoA overexpression increases glucose catabolism and maintains a more immature phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data point to an important contribution of MondoA to leukemia aggressiveness and make MondoA a potential candidate for targeted treatment of ALL.
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Clinical features and relapse rates after surgery in type 1 autoimmune pancreatitis differ from type 2: a study of 114 surgically treated European patients.
Pancreatology
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At the recent consensus conference on autoimmune pancreatitis (AIP) in Honolulu, we presented preliminary data from our study of surgically treated AIP patients. Our data strongly supported the separation of AIP into type 1 and type 2. Our study is based on a total of 114 surgically treated European AIP patients. Our aims were to elucidate serum IgG4 elevation, other organ involvement, relapse of disease, steroid treatment and diabetes after surgery in 114 surgically treated European AIP patients.
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Diet intervention reduces uptake of ?v?3 integrin-targeted PET tracer 18F-galacto-RGD in mouse atherosclerotic plaques.
J Nucl Cardiol
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Expression of ?(v)?(3) integrin has been proposed as a marker for atherosclerotic lesion inflammation. We studied whether diet intervention reduces uptake of ?(v)?(3) integrin-targeted positron emission tomography tracer (18)F-galacto-RGD in mouse atherosclerotic plaques.
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New mouse models for metabolic bone diseases generated by genome-wide ENU mutagenesis.
Mamm. Genome
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Metabolic bone disorders arise as primary diseases or may be secondary due to a multitude of organ malfunctions. Animal models are required to understand the molecular mechanisms responsible for the imbalances of bone metabolism in disturbed bone mineralization diseases. Here we present the isolation of mutant mouse models for metabolic bone diseases by phenotyping blood parameters that target bone turnover within the large-scale genome-wide Munich ENU Mutagenesis Project. A screening panel of three clinical parameters, also commonly used as biochemical markers in patients with metabolic bone diseases, was chosen. Total alkaline phosphatase activity and total calcium and inorganic phosphate levels in plasma samples of F1 offspring produced from ENU-mutagenized C3HeB/FeJ male mice were measured. Screening of 9,540 mice led to the identification of 257 phenodeviants of which 190 were tested by genetic confirmation crosses. Seventy-one new dominant mutant lines showing alterations of at least one of the biochemical parameters of interest were confirmed. Fifteen mutations among three genes (Phex, Casr, and Alpl) have been identified by positional-candidate gene approaches and one mutation of the Asgr1 gene, which was identified by next-generation sequencing. All new mutant mouse lines are offered as a resource for the scientific community.
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Foxp3+ regulatory T cells protect the liver from immune damage and compromise virus control during acute experimental hepatitis B virus infection in mice.
Hepatology
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The strength of antiviral T cell responses correlates with clearance of hepatitis B virus (HBV) infection, but the immunological mechanisms mitigating or suppressing HBV-specific T cells are still poorly understood. In this study, we examined the role of CD4(+) Foxp3(+) regulatory T cells (Tregs) in a mouse model of acute HBV infection. We initiated HBV infection via an adenoviral vector transferring a 1.3-fold overlength HBV genome (AdHBV) into transgenic DEREG mice, where Tregs can be transiently but selectively depleted by injection of diphtheria toxin. The effect of Treg depletion on the outcome of HBV infection was characterized by detailed virological, immunological, and histopathological analysis. Numbers of Tregs increase in the liver rapidly after initiation of HBV replication. Initial depletion of Tregs revealed their complex regulatory function during acute infection. Tregs mitigated immunomediated liver damage by down-regulating the antiviral activity of effector T cells by limiting cytokine production and cytotoxicity, but did not influence development of HBV-specific CD8 T cells or development of memory T cells. Furthermore, Tregs controlled the recruitment of innate immune cells such as macrophages and dendritic cells to the infected liver. As a consequence, Tregs significantly delayed clearance of HBV from blood and infected hepatocytes.
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The impact of the activated stroma on pancreatic ductal adenocarcinoma biology and therapy resistance.
Curr. Mol. Med.
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Around 95% of patients diagnosed with pancreatic cancer will die of their disease within 5 years, three quarters within a year. The major hurdle in improving prognosis is the lack of a therapeutic time window. Early cancerous lesions are far beneath our threshold of detection. Therefore, at the time of diagnosis even early (T1) tumors can be metastatic and resistant to conventional treatments. Several therapies targeting epithelial tumor cells-all showing impressive results in vitro and in animal experiments-have failed to show relevant effects in clinical trials. This discrepancy between experimental data and clinical reality results mostly from the inefficiency of our current experimental setups in recreating the tumor microenvironment. Forming more than 80% of the tumor mass, the fibrotic stroma of pancreatic ductal adenocarcinoma is not a passive scaffold for the malignant cells but an active player in carcinogenesis. This component is mostly missing in the xeno-/allograft- mouse models. Although tumors are bigger if stellate cells are co-implanted, due to the disproportionate cancer/stromal cell ratio and -possibly- too rapid tumor growth, the stromal reaction is much smaller than in human pancreatic cancer. One the other hand, desmoplasia is present only in some of the genetically engineered mouse models. Clinically, stromal activity of the pancreatic ductal adenocarcinoma has as great an impact on patient prognosis as the lymph node status of the tumor. The exact molecular mechanisms behind this observation remain obscure. However, one possible fundamental biologic explanation could be that selective pressure applied by the stroma leads to the evolution of cancer cells. Consequently, somatic evolution of invasive cancer could be viewed as a sequence of phenotypical adaptations to this barrier, highlighting the importance of the fibrotic tumor microenvironment in the behavior of pancreatic cancer. In this review, the interaction of the epithelial tumor cells with the stroma in humans and in various animal models is scrutinized, and novel therapeutic options for uncoupling cancer-stroma interactions are discussed.
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JoVE Visualize is a tool created to match the last 5 years of PubMed publications to methods in JoVE's video library.

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We use abstracts found on PubMed and match them to JoVE videos to create a list of 10 to 30 related methods videos.

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In developing our video relationships, we compare around 5 million PubMed articles to our library of over 4,500 methods videos. In some cases the language used in the PubMed abstracts makes matching that content to a JoVE video difficult. In other cases, there happens not to be any content in our video library that is relevant to the topic of a given abstract. In these cases, our algorithms are trying their best to display videos with relevant content, which can sometimes result in matched videos with only a slight relation.