bluuebunny/crossref_metadata_2025_split huggingface dataset:
Targeted Expression of Human
MYCN
Selectively Causes Pancreatic Neuroendocrine Tumors in Transgenic Zebrafish
Authors: Yang Hong Wei , Kutok Jeffery L. , Lee Nam Hyuk , Piao Hui Ying , Fletcher Christopher D. M. , Kanki John P. , Look A. Thomas 
Published: September 2005

Abstract
The zebrafish model organism has been used extensively for studies of genetic pathways in development, indicating its potential applicability to cancer. Here we show that targeted expression of MYCN in cells of the pancreatic islet induces neuroendocrine carcinoma. Four transgenic fish developed abdominal tumors between 4 and 6 months of age, and histologic analysis revealed lobulated arrangements of neoplastic cells with expression of the MYCN transgene. The tumors also expressed insulin mRNA, and pancreatic exocrine cells and ducts were identified within the neoplasms, indicating a pancreatic origin for the tumor. Transmission electron microscopy revealed cytoplasmic, endocrine-dense core granules, analogous to those found in human neuroendocrine tumors. Our studies establish a zebrafish transgenic model of pancreatic neuroendocrine carcinoma, setting the stage to evaluate molecular pathways downstream of MYCN in this vertebrate forward genetic model system.
VEGF165b, an Inhibitory Vascular Endothelial Growth Factor Splice Variant
Authors: Woolard Jeanette , Wang Wen-Ying , Bevan Heather S. , Qiu Yan , Morbidelli Lucia , Pritchard-Jones Rowan O. , Cui Tai-Gen , Sugiono Marto , Waine Elizabeth , Perrin Rachel , Foster Rebecca , Digby-Bell Jonathon , Shields Jacqueline D. , Whittles Cheryl E. , Mushens Rosey E. , Gillatt David A. , Ziche Marina , Harper Steven J. , Bates David O. 
Published: September 2005

Abstract
Growth of new blood vessels (angiogenesis), required for all tumor growth, is stimulated by the expression of vascular endothelial growth factor (VEGF). VEGF is up-regulated in all known solid tumors but also in atherosclerosis, diabetic retinopathy, arthritis, and many other conditions. Conventional VEGF isoforms have been universally described as proangiogenic cytokines. Here, we show that an endogenous splice variant, VEGF165b, is expressed as protein in normal cells and tissues and is circulating in human plasma. We also present evidence for a sister family of presumably inhibitory splice variants. Moreover, these isoforms are down-regulated in prostate cancer. We also show that VEGF165b binds VEGF receptor 2 with the same affinity as VEGF165 but does not activate it or stimulate downstream signaling pathways. Moreover, it prevents VEGF165-mediated VEGF receptor 2 phosphorylation and signaling in cultured cells. Furthermore, we show, with two different in vivo angiogenesis models, that VEGF165b is not angiogenic and that it inhibits VEGF165-mediated angiogenesis in rabbit cornea and rat mesentery. Finally, we show that VEGF165b expressing tumors grow significantly more slowly than VEGF165-expressing tumors, indicating that a switch in splicing from VEGF165 to VEGF165b can inhibit tumor growth. These results suggest that regulation of VEGF splicing may be a critical switch from an antiangiogenic to a proangiogenic phenotype.
Immunogenicity of Constitutively Active V599EBRaf
Authors: Andersen Mads Hald , Fensterle Joachim , Ugurel Selma , Reker Sine , Houben Roland , Guldberg Per , Berger Thomas G. , Schadendorf Dirk , Trefzer Uwe , Bröcker Eva-B. , Straten Per thor , Rapp Ulf R. , Becker Jürgen C. 
Published: September 2005

Abstract
Activating BRAF somatic missense mutations within the kinase domain are present in 60–66% of melanomas. The vast majority of these represent a single substitution of glutamate for valine (V599E). Here, we demonstrate spontaneous HLA-B*2705-restricted cytotoxic T-cell responses against an epitope derived from V599EBRaf. These T-cell responses were mutation specific as the corresponding epitope derived from wild-type BRaf was not recognized. The loss of the V599EBRAF genotype during progression from primary to metastatic melanoma in patients with V599EBRaf specific T-cell responses suggests an active immune selection of nonmutated melanoma clones by the tumor-bearing host.
The Duration of Nuclear Extracellular Signal-Regulated Kinase 1 and 2 Signaling during Cell Cycle Reentry Distinguishes Proliferation from Apoptosis in Response to Asbestos
Authors: Yuan Ziqiang , Taatjes Douglas J. , Mossman Brooke T. , Heintz Nicholas H. 
Published: September 2005

Abstract
Asbestos exposure causes activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) in lung epithelial cells, the targets of asbestos-associated lung carcinomas. The functional significance of ERK1/2 activation in pulmonary epithelial and mesothelial cells is unclear. Using serum-stimulated mouse alveolar type II epithelial cells as a model for cell cycle reentry, we show that the duration of phospho-ERK1/2 in the nucleus determines cell fate in response to crocidolite asbestos. In response to 10% serum, a proliferative stimulus, phosphorylated ERK1/2 initially accumulated in the nucleus, and reduction of nuclear phospho-ERK1/2 after 2 to 4 hours was followed by expression of cyclin D1 and S-phase entry. Low levels of asbestos (&lt;0.5 μg/cm2) promoted S-phase entry in low (2%) serum through an epidermal growth factor receptor-dependent pathway but did not promote cell cycle progression or induce apoptosis in the presence of high (10%) serum-containing medium. Higher levels of asbestos (1.0 to 5.0 μg/cm2) prolonged the localization of phospho-ERK1/2 in the nucleus in the presence of high serum, impeded S-phase entry, and induced apoptosis in a dose-dependent manner. Immunofluorescence microscopy indicated that the duration of signaling by phospho-ERK1/2 in the nucleus was predictive of cell fate at any concentration of asbestos. After 8 hours of exposure, cells with nuclear phospho-ERK1/2 also were positive for nuclear localization of apoptosis-inducing factor (AIF), an early event in apoptosis. In contrast, asbestos-exposed cells that displayed cytoplasmic phospho-ERK1/2 at 8 hours expressed cyclin D1 and proceeded to S phase. Our studies show that prolonged localization of phospho-ERK1/2 in the nucleus is incompatible with expression of cyclin D1 and is predictive of asbestos-associated cell death by AIF, thereby providing an approach for determining cell fate in asbestos-induced tumorigenesis.
Methylation-Associated Silencing of the
Heat Shock Protein 47
Gene in Human Neuroblastoma
Authors: Yang Qiwei , Liu Shuqing , Tian Yufeng , Hasan Chiler , Kersey Donna , Salwen Helen R. , Chlenski Alexandre , Perlman Elizabeth J. , Cohn Susan L. 
Published: September 2005

Abstract
Hypermethylation of gene promoter CpG islands is a frequent mechanism for gene inactivation in a variety of human cancers, including neuroblastoma (NB). We demonstrated recently that treatment with the demethylating agent 5′-aza-2′-deoxycytidine (5-Aza-dC) significantly inhibited NB growth in vivo. In an effort to identify the genes and biological pathways that are responsible for the impaired NB tumor growth observed after treatment with 5-Aza-dC, we performed genome-wide gene expression analysis of control and treated NBL-W-S NB cells. We found ≥3-fold changes in expression of 44 genes that play roles in angiogenesis, apoptosis, cell adhesion, transcriptional regulation, and signal transduction. The gene encoding heat shock protein 47 (Hsp47), a collagen-specific molecular chaperon, was up-regulated &gt;80-fold after 5-Aza-dC treatment. Expression studies confirmed that Hsp47 is silenced in a subset of NB cell lines and tumors. We also show that silencing of Hsp47 in NB cells is associated with aberrant methylation of promoter CpG islands and that Hsp47 expression can be restored after treatment with 5-Aza-dC. A strong correlation between Hsp47 and collagen type I and IV expression was seen in NB cells. Interestingly, tumorigenicity was inversely correlated with the level of collagen expression in NB cell lines, and higher levels of collagen were detected in mature NB tumors that are associated with favorable outcome compared with undifferentiated, advanced-stage NBs. Our studies support a role for Hsp47 in the regulation of collagen type I and IV production in NB cells and suggest that the level of collagen expression may influence NB tumor phenotype.
Colony-Stimulating Factor-1 Blockade by Antisense Oligonucleotides and Small Interfering RNAs Suppresses Growth of Human Mammary Tumor Xenografts in Mice
Authors: Aharinejad Seyedhossein , Paulus Patrick , Sioud Mouldy , Hofmann Michael , Zins Karin , Schäfer Romana , Stanley E. Richard , Abraham Dietmar 
Published: September 2005

Abstract
Colony-stimulating factor (CSF)-1 is the primary regulator of tissue macrophage production. CSF-1 expression is correlated with poor prognosis in breast cancer and is believed to enhance mammary tumor progression and metastasis through the recruitment and regulation of tumor-associated macrophages. Macrophages produce matrix metalloproteases (MMPs) and vascular endothelial growth factor, which are crucial for tumor invasion and angiogenesis. Given the important role of CSF-1, we hypothesized that blockade of CSF-1 or the CSF-1 receptor (the product of the c-fms proto-oncogene) would suppress macrophage infiltration and mammary tumor growth. Human MCF-7 mammary carcinoma cell xenografts in mice were treated with either mouse CSF-1 antisense oligonucleotide for 2 weeks or five intratumoral injections of either CSF-1 small interfering RNAs or c-fms small interfering RNAs. These treatments suppressed mammary tumor growth by 50%, 45%, and 40%, respectively, and selectively down-regulated target protein expression in tumor lysates. Host macrophage infiltration; host MMP-12, MMP-2, and vascular endothelial growth factor A expression; and endothelial cell proliferation within tumors of treated mice were decreased compared with tumors in control mice. In addition, mouse survival significantly increased after CSF-1 blockade. These studies demonstrate that CSF-1 and CSF-1 receptor are potential therapeutic targets for the treatment of mammary cancer.
Celastraceae Sesquiterpenes as a New Class of Modulators That Bind Specifically to Human P-Glycoprotein and Reverse Cellular Multidrug Resistance
Authors: Muñoz-Martínez Francisco , Lu Peihua , Cortés-Selva Fernando , Pérez-Victoria José María , Jiménez Ignacio A. , Ravelo Ángel G. , Sharom Frances J. , Gamarro Francisco , Castanys Santiago 
Published: September 2005

Abstract
Overexpression of ABCB1 (MDR1) P-glycoprotein, a multidrug efflux pump, is one mechanism by which tumor cells may develop multidrug resistance (MDR), preventing the successful chemotherapeutic treatment of cancer. Sesquiterpenes from Celastraceae family are natural compounds shown previously to reverse MDR in several human cancer cell lines and Leishmania strains. However, their molecular mechanism of reversion has not been characterized. In the present work, we have studied the ability of 28 dihydro-β-agarofuran sesquiterpenes to reverse the P-glycoprotein-dependent MDR phenotype and elucidated their molecular mechanism of action. Cytotoxicity assays using human MDR1-transfected NIH-3T3 cells allowed us to select the most potent sesquiterpenes reversing the in vitro resistance to daunomycin and vinblastine. Flow cytometry experiments showed that the above active compounds specifically inhibited drug transport activity of P-glycoprotein in a saturable, concentration-dependent manner (Ki down to 0.24 ± 0.01 μmol/L) but not that of ABCC1 (multidrug resistance protein 1; MRP1), ABCC2 (MRP2), and ABCG2 (breast cancer resistance protein; BCRP) transporters. Moreover, sesquiterpenes inhibited at submicromolar concentrations the P-glycoprotein-mediated transport of [3H]colchicine and tetramethylrosamine in plasma membrane from CHRB30 cells and P-glycoprotein-enriched proteoliposomes, supporting that P-glycoprotein is their molecular target. Photoaffinity labeling in plasma membrane and fluorescence spectroscopy experiments with purified protein suggested that sesquiterpenes interact with transmembrane domains of P-glycoprotein. Finally, sesquiterpenes modulated P-glycoprotein ATPase-activity in a biphasic, concentration-dependent manner: they stimulated at very low concentrations but inhibited ATPase activity as noncompetitive inhibitors at higher concentrations. Sesquiterpenes from Celastraceae are promising P-glycoprotein modulators with potential applications in cancer chemotherapy because of their MDR reversal potency and specificity for P-glycoprotein.
SD-208, a Novel Transforming Growth Factor β Receptor I Kinase Inhibitor, Inhibits Growth and Invasiveness and Enhances Immunogenicity of Murine and Human Glioma CellsIn vitroandIn vivo
Authors: Uhl Martin , Aulwurm Steffen , Wischhusen Jörg , Weiler Markus , Ma Jing Ying , Almirez Ramona , Mangadu Ruban , Liu Yu-Wang , Platten Michael , Herrlinger Ulrich , Murphy Alison , Wong Darren H. , Wick Wolfgang , Higgins Linda S. , Weller Michael 
Published: September 2005

AbstractThe cytokine transforming growth factor (TGF)-β, by virtue of its immunosuppressive and promigratory properties, has become a major target for the experimental treatment of human malignant gliomas. Here we characterize the effects of a novel TGF-β receptor (TGF-βR) I kinase inhibitor, SD-208, on the growth and immunogenicity of murine SMA-560 and human LN-308 glioma cells in vitro and the growth of and immune response to intracranial SMA-560 gliomas in syngeneic VM/Dk mice in vivo. SD-208 inhibits the growth inhibition of TGF-β–sensitive CCL64 cells mediated by recombinant TGF-β1 or TGF-β2 or of TGF-β–containing glioma cell supernatant at an EC50 of 0.1 μmol/L. SD-208 blocks autocrine and paracrine TGF-β signaling in glioma cells as detected by the phosphorylation of Smad2 or TGF-β reporter assays and strongly inhibits constitutive and TGF-β–evoked migration and invasion, but not viability or proliferation. Peripheral blood lymphocytes or purified T cells, cocultured with TGF-β–releasing LN-308 glioma cells in the presence of SD-208, exhibit enhanced lytic activity against LN-308 targets. The release of interferon γ and tumor necrosis factor α by these immune effector cells is enhanced by SD-208, whereas the release of interleukin 10 is reduced. SD-208 restores the lytic activity of polyclonal natural killer cells against glioma cells in the presence of recombinant TGF-β or of TGF-β–containing glioma cell supernatant. The oral bioavailability of SD-208 was verified by demonstrating the inhibition of TGF-β–induced Smad phosphorylation in spleen and brain. Systemic SD-208 treatment initiated 3 days after the implantation of SMA-560 cells into the brains of syngeneic VM/Dk mice prolongs their median survival from 18.6 to 25.1 days. Histologic analysis revealed no difference in blood vessel formation, proliferation, or apoptosis. However, animals responding to SD-208 showed an increased tumor infiltration by natural killer cells, CD8 T cells, and macrophages. These data define TGF-β receptor I kinase inhibitors such as SD-208 as promising novel agents for the treatment of human malignant glioma and other conditions associated with pathological TGF-β activity.
Human Prolactin Receptor Variants in Breast Cancer
Authors: Meng Jianping , Tsai-Morris Chon-Hwa , Dufau Maria L. 
Published: September 2005

Abstract
Prolactin plays an essential role in the development of rodent mammary tumors and is a potent mitogen in human normal and cancerous breast tissues/cells. In this study, we have analyzed the expression of prolactin receptors, including the long receptor form (LF; stimulatory) and two novel short forms (SFs; S1a and S1b) derived from alternative splicing that are inhibitory of the activation induced by prolactin through the LF. Southern analysis of breast cancer profiling arrays revealed that 29 patients (group I) expressed an elevated LF, 10 patients (group II) showed decreased LF, and 8 patients (group III) had no change relative to the adjacent normal tissue. Their respective SF expression was increased in 21 patients of group I and generally decreased in groups II and III. However, the ratio of SF to LF was significantly decreased in 76% of the breast tumors and distributed evenly among the groups. Quantification of differential expression of prolactin receptor variants by real-time PCR in 15 pairs of human normal and tumor breast-matched tissues revealed a similar significant decrease in the ratio of SF to LF in the tumor tissue. Consistent lower ratio of SFs to LFs was confirmed in 8 of ten different breast cancer cell lines compared with normal mammary Hs578Bst and MCF10A cells. Because SFs act as dominant negative regulators of the stimulatory actions of the LF in vitro, their relatively reduced expression in cancer could cause gradations of unopposed prolactin-mediated LF stimulatory function and contribute to breast tumor development/progression.
Overexpression of Transforming Growth Factor β1 in Head and Neck Epithelia Results in Inflammation, Angiogenesis, and Epithelial Hyperproliferation
Authors: Lu Shi-Long , Reh Douglas , Li Allen G. , Woods Jennifer , Corless Christopher L. , Kulesz-Martin Molly , Wang Xiao-Jing 
Published: September 2005

Abstract
In the present study, we show that transforming growth factor β1 (TGF-β1) was frequently overexpressed in human head and neck squamous cell carcinomas (HNSCCs) and adjacent tissues in comparison with normal head and neck tissues. To determine the role of TGF-β1 overexpression in HNSCC carcinogenesis, we generated transgenic mice in which TGF-β1 transgene expression can be induced in head and neck epithelia. TGF-β1 transgene induction in head and neck epithelia, at levels similar to those in human HNSCCs, caused severe inflammation and angiogenesis. Consequently, TGF-β1-transgenic epithelia exhibited hyperproliferation. These phenotypes correlated with enhanced Smad signaling in transgenic epithelia and stroma. Our study suggests that TGF-β1 overexpression at early stages of HNSCC formation provides a tumor promoting microenvironment.
Cleavage of β-Catenin by Calpain in Prostate and Mammary Tumor Cells
Authors: Rios-Doria Jonathan , Kuefer Rainer , Ethier Stephen P. , Day Mark L. 
Published: September 2005

Abstract
Mutations in the NH2-terminal regulatory domain of the β-catenin gene lead to aberrant stabilization and accumulation of the protein and increased TCF/LEF-dependent transcription. Although these mutations are common in some cancers, they are infrequent in prostate and breast cancer. We have found that metastatic prostate cancer specimens, obtained through a rapid autopsy tissue procurement program, expressed a novel Mr 75,000 proteolytic fragment of β-catenin (β-cat75). β-Cat75 was also expressed in multiple prostate and breast cancer cell lines and was closely associated with the activity of the calcium-dependent protease, calpain. In a prostate cancer cDNA microarray, m-calpain RNA levels were found to be significantly increased in metastatic disease compared with normal prostate. We showed calpain-dependent generation of β-cat75 in cell culture and in vitro. Molecular mapping revealed that calpain cleavage removed the NH2-terminal regulatory domain of the β-catenin protein. Treatment of MCF-7 cells with ionomycin led to increased accumulation of β-cat75 in the nucleus and TCF-dependent transcriptional activity. Overexpression of a similar β-catenin fragment that lacks the NH2-terminal 132 amino acids and has transforming potential activated TCF-dependent transcription. Given the low frequency of mutation-induced activation of β-catenin in prostate and breast cancers, proteolytic cleavage of β-catenin by calpain may represent a novel mechanism by which the protein is activated during tumorigenesis.
Angiopoietin-3 Inhibits Pulmonary Metastasis by Inhibiting Tumor Angiogenesis
Authors: Xu Yin , Liu Yao-juan , Yu Qin 
Published: September 2005

Abstract
Angiopoietins (Ang-1, Ang-2, and Ang-3) are the ligands of Tie-2 receptor tyrosine kinase. The essential roles of Ang-1 and Tie-2 in embryonic angiogenesis have been established, and studies have demonstrated the involvement of Ang-1 and Ang-2 in tumor angiogenesis. However, the role of Ang-3 in tumor angiogenesis and metastasis and the mechanism underlying its function are totally unknown. We have shown recently that Ang-3 is tethered on cell surface via heparan sulfate proteoglycans. In our current study, we have demonstrated that overexpression of Ang-3 inhibits pulmonary metastasis of Lewis lung carcinoma and TA3 mammary carcinoma (TA3) cells by inhibiting tumor angiogenesis and promoting apoptosis of the tumor cells. In addition, we have demonstrated that the binding of Ang-3 to the cell surface is required for the effective inhibition of Ang-3 on tumor metastasis and that Ang-3 inhibits endothelial cell proliferation and survival and blocks Ang-1- and vascular endothelial growth factor-induced activation of extracellular signal-regulated kinase 1/2 and Akt kinases, which likely underlie the Ang-3-mediated inhibition on tumor angiogenesis and metastasis.
Pulmonary Prostacyclin Synthase Overexpression Chemoprevents Tobacco Smoke Lung Carcinogenesis in Mice
Authors: Keith Robert L. , Miller York E. , Hudish Tyler M. , Girod Carlos E. , Sotto-Santiago Sylk , Franklin Wilbur A. , Nemenoff Raphael A. , March Thomas H. , Nana-Sinkam S. Patrick , Geraci Mark W. 
Published: September 2005

Abstract
Increased pulmonary production of prostaglandin I2 (prostacyclin) by lung-specific overexpression of prostacyclin synthase decreases lung tumor incidence and multiplicity in chemically induced murine lung cancer models. We hypothesized that pulmonary prostacyclin synthase overexpression would prevent lung carcinogenesis in tobacco-smoke exposed mice. Murine exposure to tobacco smoke is an established model of inducing pulmonary adenocarcinomas and allows for the testing of potential chemopreventive strategies. Transgenic FVB/N mice with lung-specific prostacyclin synthase overexpression were exposed to mainstream cigarette smoke for 22 weeks and then held unexposed for an additional 20 weeks. All of the exposed animals developed bronchiolitis analogous to the respiratory bronchiolitis seen in human smokers. The transgenic mice, when compared with smoke-exposed transgene negative littermates, had significant decreases in tumor incidence and multiplicity. Significantly fewer transgenics (6 of 15; 40%) developed tumors compared with the tumor incidence in wild-type littermates (16 of 19; 84%; Fisher’s exact test, P = 0.012). Tumor multiplicity was also significantly decreased in the transgenic animals (tg+ = 0.4 ± 0.5 versus wild-type = 1.2 ± 0.86 tumors/mouse; P &lt; 0.001). Targeted prostaglandin levels at the time of sacrifice revealed significantly elevated prostaglandin I2 levels in the transgenic animals, coupled with significantly decreased prostaglandin E2 levels. Gene expression analysis of isolated type II pneumocytes suggests potential explanations for the observed chemoprevention, with Western blot analysis confirming decreased expression of cytochrome p450 2e1. These studies extend our previous studies and demonstrate that manipulation of prostaglandin production distal to cyclooxygenase significantly reduces lung carcinogenesis in a tobacco smoke exposure model, and gene expression studies show critical alterations in antioxidation, immune response, and cytokine pathways.