bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conditional BRAFV600E Expression Induces DNA Synthesis, Apoptosis, Dedifferentiation, and Chromosomal Instability in Thyroid PCCL3 Cells
Authors: Mitsutake Norisato , Knauf Jeffrey A. , Mitsutake Shin , Mesa Cleo , Zhang Lei , Fagin James A. 
Published: September 2005

Abstract
The activating mutation BRAFT1796A is the most prevalent genetic alteration in papillary thyroid carcinomas (PTC). It is associated with advanced PTCs, suggesting that this oncoprotein confers thyroid cancers with more aggressive properties. BRAFT1796A is also observed in thyroid micropapillary carcinomas and may thus be an early event in tumor development. To explore its biological consequences, we established doxycycline-inducible BRAFV600E-expressing clonal lines derived from well-differentiated rat thyroid PCCL3 cells. Expression of BRAFV600E did not induce growth in the absence of thyrotropin despite increasing DNA synthesis, which is likely explained because of a concomitant increase in apoptosis. Thyrotropin-dependent cell growth and DNA synthesis were reduced by BRAFV600E because of decreased thyrotropin responsiveness associated with inhibition of thyrotropin receptor gene expression. These results are similar to those obtained following conditional expression of RET/PTC. However, in contrast to RET/PTC, BRAF activation did not impair key activation steps distal to the thyrotropin receptor, such as forskolin-induced adenylyl cyclase activity or cyclic AMP–induced DNA synthesis. We reported previously that acute RET/PTC expression in PCCL3 cells did not induce genomic instability. By contrast, induction of BRAFV600E expression increased the frequency of micronuclei by both clastogenic and aneugenic events. These data indicate that BRAFV600E expression confers thyroid cells with little growth advantage because of concomitant activation of DNA synthesis and apoptosis. However, in contrast to RET/PTC, BRAFV600E may facilitate the acquisition of secondary genetic events through induction of genomic instability, which may account for its aggressive properties.
p53CSV, a Novel p53-Inducible Gene Involved in the p53-Dependent Cell-Survival Pathway
Authors: Park Woong-Ryeon , Nakamura Yusuke 
Published: September 2005

Abstract
Although a number of p53 target genes have been identified, the mechanisms of p53-dependent activities that determine cellular survival or death are still not fully understood. Here we report isolation of a novel p53 target gene, designated p53-inducible cell-survival factor (p53CSV). p53CSV contains a p53-binding site within its second exon and the reduction of expression by small interfering RNA enhanced apoptosis, whereas overexpression protected cells from apoptosis caused by DNA damage. p53CSV is induced significantly when cells have a low level of genotoxic stresses, but not when DNA damage is severe. p53CSV can modulate apoptotic pathways through interaction with Hsp70 that probably inhibits activity of apoptosis protease activating factor-1. Our results imply that under specific conditions of stress, p53 regulates transcription of p53CSV and that p53CSV is one of the important players in the p53-mediated cell survival.
Discovery of Aberrant Expression of R-RAS by Cancer-Linked DNA Hypomethylation in Gastric Cancer Using Microarrays
Authors: Nishigaki Michiko , Aoyagi Kazuhiko , Danjoh Inaho , Fukaya Masahide , Yanagihara Kazuyoshi , Sakamoto Hiromi , Yoshida Teruhiko , Sasaki Hiroki 
Published: September 2005

Abstract
Although hypomethylation was the originally identified epigenetic change in cancer, it was overlooked for many years in preference to hypermethylation. Recently, gene activation by cancer-linked hypomethylation has been rediscovered. However, in gastric cancer, genome-wide screening of the activated genes has not been found. By using microarrays, we identified 1,383 gene candidates reactivated in at least one cell line of eight gastric cancer cell lines after treatment with 5-aza-2′deoxycytidine and trichostatin A. Of the 1,383 genes, 159 genes, including oncogenes ELK1, FRAT2, R-RAS, RHOB, and RHO6, were further selected as gene candidates that are silenced by DNA methylation in normal stomach mucosa but are activated by DNA demethylation in a subset of gastric cancers. Next, we showed that demethylation of specific CpG sites within the first intron of R-RAS causes activation in more than half of gastric cancers. Introduction of siRNA into R-RAS-expressing cells resulted in the disappearance of the adhered cells, suggesting that functional blocking of the R-RAS-signaling pathway has great potential for gastric cancer therapy. Our extensive gene list provides other candidates for this class of oncogene.
CD4+ T Cells Are Able to Promote Tumor Growth through Inhibition of Tumor-Specific CD8+ T-Cell Responses in Tumor-Bearing Hosts
Authors: den Boer Annemieke Th. , van Mierlo Geertje J.D. , Fransen Marieke F. , Melief Cornelis J.M. , Offringa Rienk , Toes René E.M. 
Published: September 2005

Abstract
Modulation of the immune response by established tumors may contribute to the limited success of therapeutic vaccination for the treatment of cancer compared with vaccination in a preventive setting. We analyzed the contribution of the CD4+ T-cell population to the induction or suppression of tumor-specific CD8+ T cells in a tumor model in which eradication of tumors crucially depends on CD8+ T cell–mediated immunity. Vaccine-mediated induction of protective antitumor immunity in the preventive setting (i.e., before tumor challenge) was CD4+ T cell dependent because depletion of this T-cell subset prevented CD8+ T-cell induction. In contrast, depletion of CD4+ cells in mice bearing established E1A+ tumors empowered the mice to raise strong CD8+ T-cell immunity capable of tumor eradication without the need for tumor-specific vaccination. Spontaneous eradication of tumors, which had initially grown out, was similarly observed in MHC class II–deficient mice, supporting the notion that the tumor-bearing mice harbor a class II MHC–restricted CD4+ T-cell subset capable of suppressing a tumor-specific CD8+ T-cell immune response. The deleterious effects of the presence of CD4+ T cells in tumor-bearing hosts could be overcome by CD40-triggering or injection of CpG. Together these results show that CD4+ T cells with a suppressive activity are rapidly induced following tumor development and that their suppressive effect can be overcome by agents that activate professional antigen-presenting cells. These observations are important for the development of immune interventions aiming at treatment of cancer.
Tumor Suppressor Activity and Epigenetic Inactivation of Hepatocyte Growth Factor Activator Inhibitor Type 2/SPINT2 in Papillary and Clear Cell Renal Cell Carcinoma
Authors: Morris Mark R. , Gentle Dean , Abdulrahman Mahera , Maina Esther N. , Gupta Kunal , Banks Rosamonde E. , Wiesener Michael S. , Kishida Takeshi , Yao Masahiro , Teh Bin , Latif Farida , Maher Eamonn R. 
Published: September 2005

Abstract
Following treatment with a demethylating agent, 5 of 11 renal cell carcinoma (RCC) cell lines showed increased expression of hepatocyte growth factor (HGF) activator inhibitor type 2 (HAI-2/SPINT2/Bikunin), a Kunitz-type protease inhibitor that regulates HGF activity. As activating mutations in the MET proto-oncogene (the HGF receptor) cause familial RCC, we investigated whether HAI-2/SPINT2 might act as a RCC tumor suppressor gene. We found that transcriptional silencing of HAI-2 in RCC cell lines was associated with promoter region methylation and HAI-2/SPINT2 protein expression was down-regulated in 30% of sporadic RCC. Furthermore, methylation-specific PCR analysis revealed promoter region methylation in 30% (19 of 64) of clear cell RCC and 40% (15 of 38) of papillary RCC, whereas mutation analysis (in 39 RCC cell lines and primary tumors) revealed a missense substitution (P111S) in one RCC cell line. Restoration of HAI-2/SPINT2 expression in a RCC cell line reduced in vitro colony formation, but the P111S mutant had no significant effect. Increased cell motility associated with HAI-2/SPINT2 inactivation was abrogated by treatment with extracellular signal-regulated kinase (ERK)/mitogen-activated protein kinase (MAPK) and phospholipase C-γ inhibitors, but not by an inhibitor of atypical protein kinase C. These findings are consistent with frequent epigenetic inactivation of HAI-2/SPINT2, causing loss of RCC tumor suppressor activity and implicate abnormalities of the MET pathway in clear cell and papillary sporadic RCC. This information provides opportunities to develop novel targeted approaches to the treatment of RCC.
Identification of Metastasis-Associated Receptor Tyrosine Kinases in Non–Small Cell Lung Cancer
Authors: Müller-Tidow Carsten , Diederichs Sven , Bulk Etmar , Pohle Thorsten , Steffen Björn , Schwäble Joachim , Plewka Sylvia , Thomas Michael , Metzger Ralf , Schneider Paul M. , Brandts Christian H. , Berdel Wolfgang E. , Serve Hubert 
Published: September 2005

Abstract
Development of distant metastasis after tumor resection is the leading cause of death in early-stage non–small cell lung cancer (NSCLC). Receptor tyrosine kinases (RTK) are involved in tumorigenesis but only few RTKs have been systematically studied in NSCLC. Here, we provide quantitative real-time reverse transcription-PCR expression data of all RTKs (n = 56) in primary tumors of 70 patients with early-stage (I-IIIA) NSCLC. Overall, 33 RTKs were expressed in at least 25% of the patients. Several RTKs were significantly expressed higher in tumors that ultimately metastasized. The hazard risk for metastasis development in stage I/II disease was increased at least 3-fold for tumors with high expression levels of insulin receptor, neurotrophic tyrosine receptor kinase 1, epidermal growth factor receptor, ERBB2, ERBB3, platelet-derived growth factor receptor β, fibroblast growth factor receptor 1, or leukocyte tyrosine kinase. Relative risks were reduced 3-fold by expression of EPHB6 or DKFZ1. Three members of the epidermal growth factor receptor family were associated with a high risk of metastasis, emphasizing the validity of our data. High ERBB3 expression was significantly associated with decreased survival. Taken together, our genome-wide RTK expression map uncovered the previously unknown value of several RTKs as potential markers for prognosis and metastasis prediction in early-stage NSCLC. The identified RTKs represent promising novel candidates for further functional analyses.
Functional Loss of the γ-Catenin Gene through Epigenetic and Genetic Pathways in Human Prostate Cancer
Authors: Shiina Hiroaki , Breault Julia E. , Basset William W. , Enokida Hideki , Urakami Shinji , Li Long-Cheng , Okino Steven T. , Deguchi Masao , Kaneuchi Masanori , Terashima Masaharu , Yoneda Tatsuaki , Shigeno Kazushi , Carroll Peter R. , Igawa Mikio , Dahiya Rajvir 
Published: September 2005

Abstract
γ-Catenin is a cell adhesion molecule and a candidate mediator of Wnt signal transduction. We hypothesized that impaired regulation of γ-catenin through genetic and epigenetic pathways is associated with the pathogenesis of prostate cancer. To test this hypothesis, cytosine-phosphate-guanine methylation, loss of heterozygosity (LOH), and mutation status of the γ-catenin gene were analyzed in cultured prostate cancer cell lines, 180 localized prostate cancers, 69 benign prostatic hyperplasias, and 11 hormone refractory prostate cancers (HRPC). In prostate cancer cell lines (DuPro, LNCaP, ND-1, and PC3), γ-catenin mRNA transcripts were increased after 5-aza-2′-deoxycytidine treatment. In localized prostate cancer, γ-catenin expression was lower but prevalence of γ-catenin methylation was higher compared with benign prostatic hyperplasia. However, γ-catenin methylation did not correlate with Gleason sum, pT category, or capsular penetration. Among localized prostate cancers with positive γ-catenin methylation, the presence of LOH at chromosome 17q21 was closely related to down-regulation of γ-catenin mRNA expression. The γ-catenin mutations were not found in localized prostate cancers, whereas six mutations were found in five HRPCs within or close to the GSK-3β consensus motif phosphorylation site, among which four HRPCs showed strong nuclear γ-catenin accumulation. In these four HRPCs, Bcl-2 expression was increased, whereas the target of the Wnt signal, c-myc, was only expressed in one HRPC. Therefore, although epigenetic γ-catenin methylation is an early event in the development of prostate cancer, simultaneous events of epigenetic cytosine-phosphate-guanine methylation and genetic LOH may be responsible for functional loss of γ-catenin. The γ-catenin mutation related to Bcl-2 overexpression has a significant effect on the pathogenesis of HRPC. This is the first report to characterize the epigenetic and genetic regulation of γ-catenin in human prostate cancer.
Functional Idiotopes: Tumor Antigen–Directed Expression of CD8+ T-Cell Epitopes Nested in Unique NH2-terminal VH Sequence of Antiidiotypic Antibodies?
Authors: Kawano Kouichiro , Ferrone Soldano , Ioannides Constantin G. 
Published: September 2005

Abstract
Antiidiotypic antibodies have been and are being used for cancer immunotherapy based on the rationale that Ab2 carrying an “internal image” of the corresponding tumor antigen can induce tumor antigen–specific antibodies (i.e., Ab3 and inhibit tumor growth). Recent evidence indicates that Ab2 also induces cellular responses by CD4+ and CD8+ T cells. This finding has raised the question of where the short peptides, which express CD8+ T-cell–defined epitopes, are located and their relationship with the tumor antigen. We found that two of the four known Ab2 associated with tumor antigen, with known amino acid sequence, express unique NH2-terminal VH sequences which precede the framework regions. Both the unique and the shared NH2-terminal VH sequences are nested MHC class I antigen–binding peptides. These peptides were highly homologous with peptides from corresponding tumor antigen (carcinoembryonic antigen, CD55, and human high molecular weight melanoma–associated antigen) but differed from the tumor antigen peptides by the presence of the side chain known to mediate stronger forces of interaction with other atoms. The presence of candidate CTL epitopes in NH2-terminal VH of Ab2 homologous with tumor antigen may be important for the development of novel immunotherapeutic strategies for cancer.
Pulmonary Radiation Injury: Identification of Risk Factors Associated with Regional Hypersensitivity
Authors: Novakova-Jiresova Alena , van Luijk Peter , van Goor Harry , Kampinga Harm H. , Coppes Robert P. 
Published: September 2005

Abstract
Effective radiation treatment of thoracic tumors is often limited by radiosensitivity of surrounding tissues. Several experimental studies have suggested variations in radiosensitivity of different pulmonary regions. Mice and rat studies in part contradict each other and urge for a more detailed analysis. This study was designed to obtain a more comprehensive insight in radiation injury development, expression, and its regional heterogeneity in lung. The latter is obviously highly critical for optimization of radiotherapy treatment plans and may shed light on the mechanisms of lung dysfunction after irradiation. Six different but volume-equal regions in rat lung were irradiated. Whereas the severity of damage, as seen in histologic analysis, was comparable in all regions, the degree of lung dysfunction, measured as breathing rates, largely varied. During the pneumonitic phase (early: 6-12 weeks), the most sensitive regions contained a substantial part of alveolar lung parenchyma. Also, a trend for hypersensitivity was observed when the heart lay in the irradiation field. In the fibrotic phase (late: 34-38 weeks), lung parenchyma and heart-encompassing regions were the most sensitive. No impact of the heart was observed during the intermediate phase (16-28 weeks). The severity of respiratory dysfunction after partial thoracic irradiation is likely governed by an interaction between pulmonary and cardiac functional deficits. As a repercussion, more severe acute and delayed toxicity should be expected after combined lung and heart irradiation. This should be considered in the process of radiotherapy treatment planning of thoracic malignancies.
Estrogen Receptor–Binding Fragment–Associated Antigen 9 Is a Tumor-Promoting and Prognostic Factor for Renal Cell Carcinoma
Authors: Ogushi Tetsuo , Takahashi Satoru , Takeuchi Takumi , Urano Tomohiko , Horie-Inoue Kuniko , Kumagai Jinpei , Kitamura Tadaichi , Ouchi Yasuyoshi , Muramatsu Masami , Inoue Satoshi 
Published: September 2005

Abstract
The estrogen receptor–binding fragment–associated antigen 9 (EBAG9) has been identified as a primary estrogen-responsive gene in human breast cancer MCF7 cells. A high expression of EBAG9 has been observed in invasive breast cancer and advanced prostate cancer, suggesting a tumor-promoting role of the protein in malignancies. Here we show that intratumoral (i.t.) administration of small interfering RNA against EBAG9 exerted overt regression of tumors following s.c. implantation of murine renal cell carcinoma (RCC) Renca cells. Overexpression of EBAG9 did not promote the proliferation of culture Renca cells; however, the inoculated Renca cells harboring EBAG9 (Renca-EBAG9) in BALB/c mice grew faster and developed larger tumors compared with Renca cells expressing vector alone (Renca-vector). After renal subcapsular implantation, Renca-EBAG9 tumors significantly enlarged compared with Renca-vector tumors in BALB/c mice, whereas both Renca-EBAG9 and Renca-vector tumors were developed with similar volumes in BALB/c nude mice. No apparent difference was observed in specific cytotoxic T-cell responses against Renca-EBAG9 and Renca-vector cells; nonetheless, the number of infiltrating CD8+ T lymphocytes was decreased in Renca-EBAG9 subcapsular tumors. Furthermore, immunohistochemical study of EBAG9 in 78 human RCC specimens showed that intense and diffuse cytoplasmic immunostaining was observed in 87% of the cases and positive EBAG9 immunoreactivity was closely correlated with poor prognosis of the patients. Multivariate analysis revealed that high EBAG9 expression was an independent prognostic predictor for disease-specific survival (P = 0.0485). Our results suggest that EBAG9 is a crucial regulator of tumor progression and a potential prognostic marker for RCC.
Synergy of Epidermal Growth Factor Receptor Kinase Inhibitor AG1478 and ErbB2 Kinase Inhibitor AG879 in Human Colon Carcinoma Cells Is Associated with Induction of Apoptosis
Authors: Zhou Yunfei , Brattain Michael G. 
Published: September 2005

Abstract
Previous studies have shown that constitutive activation of epidermal growth factor receptor (EGFR) and ErbB2 by elevated autocrine transforming growth factor-α (TGF-α) expression plays an important role in colon cancer progression. Coexpression of EGFR and ErbB2 is found in a subset of colon cancers and may cooperatively promote cancer cell growth and survival, as heterodimerization is known to provide for diversification of signal transduction. In this study, the EGFR-selective tyrosine kinase inhibitor (TKI) AG1478 inhibited cell growth of an aggressive human colon carcinoma cell line, FET6αS26X, which harbors constitutively activated EGFR after stable transfection with TGF-α cDNA. However, AG1478 failed to induce apoptosis in FET6αS26X cells at concentrations sufficient for cell growth inhibition and complete suppression of EGFR phosphorylation. Similarly, AG879, a selective ErbB2 TKI, was incapable of inducing apoptosis in FET6αS26X cells at concentrations sufficient to inhibit cell growth and ErbB2 phosphorylation. To test the hypothesis that targeting both ErbB family members would show better efficacy than targeting the single receptors, combinations of inhibitors at fixed ratios of 1:1, 5:1, and 10:1 of AG1478 and AG879, respectively, were compared with single drugs for inhibition of cell growth. All combinations resulted in synergistic effects as indicated by combination index analysis. Synergistic inhibition was associated with induction of apoptosis as reflected by poly(ADP-ribose) polymerase cleavage, caspase-3 activation, and Annexin V staining. Finally, Western blot analysis showed significant inhibition of phosphorylation of both EGFR and ErbB2 by the combination treatment. These data suggest that the strategy to target both EGFR and ErbB2 simultaneously might result in more efficient inhibition of tumor growth than to target single receptor alone.
Assessment of a Combined, Adenovirus-Mediated Oncolytic and Immunostimulatory Tumor Therapy
Authors: Bernt Kathrin Maria , Ni Shaoheng , Tieu Anh-Thu , Lieber André 
Published: September 2005

Abstract
In this study, we identified murine breast cancer cell lines that support DNA replication of E1-deleted adenovirus vectors and which can be killed by an oncolytic adenovirus expressing adenovirus E1A and tumor necrosis factor (TNF)–related apoptosis inducing ligand (TRAIL) in a replication-dependent manner (Ad.IR-E1A/TRAIL). We showed that systemic or intratumoral (i.t.) injection of adenovirus vectors into mice increases plasma levels of proinflammatory cytokines and chemokines, including TNF-α, INF-γ, and MCP-1, which are potent inducers of dendritic cell maturation. Furthermore, we showed that in vivo expression of Flt3L from an adenovirus vector increases the number of CD11b+ and CD11c+ cells (populations that include dendritic cells) in the blood circulation. Based on these findings, we tested whether Ad.IR-E1A/TRAIL induced killing of tumor cells in combination with dendritic cell mobilization by Ad.Flt3L or, for comparison, Ad.GM-CSF would have an additive antitumor effect. As a model, we used immunocompetent C3H mice with syngeneic s.c. tumors derived from C3L5 cells. We found that vaccination of mice with C3L5 cells that underwent viral oncolysis in combination with Flt3L or granulocyte-macrophage colony-stimulating factor (GM-CSF) expression induces a systemic antitumor immune response. I.t. injection of the oncolytic and Flt3L expressing vectors into established tumors delayed tumor growth but did not cause efficient tumor elimination. This study shows the effectiveness of a combined oncolytic/immunostimulatory tumor therapy approach.
Cell Type-Specific Tumor Suppression by Ink4a and Arf in Kras-Induced Mouse Gliomagenesis
Authors: Uhrbom Lene , Kastemar Marianne , Johansson Fredrik K. , Westermark Bengt , Holland Eric C. 
Published: September 2005

Abstract
Homozygous deletion of the INK4a-ARF locus is one of the most frequent mutations found in human glioblastoma. We have previously shown that combined Ink4a-Arf loss can increase tumor incidence in both glial progenitor cells and astrocytes during mouse gliomagenesis. Here we have investigated the separate contribution of loss of each of the tumor suppressor genes in glial progenitor cells and astrocytes in Akt + Kras–induced gliomagenesis. We show that Arf is the major tumor suppressor gene in both cell types. Arf loss generated glioblastomas from both nestin-expressing glial progenitor cells and glial fibrillary acidic protein–expressing astrocytes, with a significantly higher incidence in astrocytes. Ink4a loss, on the other hand, could only significantly contribute to gliomagenesis from glial progenitor cells and the induced tumors were of lower malignancy than those seen in Arf-deficient mice. Thus, Ink4a and Arf have independent and differential tumor suppressor functions in vivo in the glial cell compartment.