bluuebunny/crossref_metadata_2025_split huggingface dataset:
Suppression of Tumor Growth by Galectin-7 Gene Transfer
Authors: Ueda Shugo , Kuwabara Ichiro , Liu Fu-Tong 
Published: September 2005

AbstractGalectin-7 is a β-galactoside-binding animal lectin specifically expressed in stratified epithelia. Its expression is inducible by p53 and is down-regulated in squamous cell carcinomas. Other investigators previously showed that galectin-7 is a proapoptotic protein, and we showed that ectopic expression of galectin-7 in HeLa cells renders the cells more sensitive to a variety of apoptotic stimuli. In the present study, we showed that ectopic expression of galectin-7 in the human colon carcinoma cell line DLD-1 also made the cells more sensitive to apoptosis under various conditions. We also found that galectin-7-transfected DLD-1 (DLD-1-Gal7) cells grew significantly more slowly than control transfectants (DLD-1-V) under normal culture conditions in the absence of apoptosis. Moreover, a significantly lower number of colonies were formed from DLD-1-Gal7 cells than from DLD-1-V cells under anchorage-independent cell growth conditions. Most importantly, tumor formation from DLD-1-Gal7 cells was dramatically reduced compared with DLD-1-V cells when these cells were inoculated s.c. into severe combined immunodeficient mice. DLD-1-Gal7 tumors showed a significantly lower proliferation rate than DLD-1-V tumors as determined by in vivo 5-bromo-2′-deoxyuridine incorporation. DLD-1-Gal7 tumors also contained a lower density of blood vessels than DLD-1-V tumors, suggesting that ectopic expression of galectin-7 suppresses angiogenesis. This may partially account for the greater suppressive effect of galectin-7 on tumor growth in vivo than in vitro. Our results show that galectin-7 has a suppressive effect on tumor growth, suggesting that galectin-7 gene transfer or other means of specifically inducing galectin-7 expression may be a new approach for management of cancers.
Microregional Effects of Gemcitabine in HCT-116 Xenografts
Authors: Huxham Lynsey A. , Kyle Alastair H. , Baker Jennifer H. E. , Nykilchuk Lani K. , Minchinton Andrew I. 
Published: September 2005

Abstract
To examine the tumor microregional effects after gemcitabine administration to mice, we mapped the location of proliferating and hypoxic cells relative to vasculature in human colon cancer xenografts. The S-phase marker bromodeoxyuridine was used as a surrogate of drug effect and administered 2 hours before tumor excision, whereas vessel position and perfusion were assessed via staining for CD31 and intravenous injection of carbocyanine, respectively. Hypoxia was detected using pimonidazole. Images of the four markers were overlaid to reveal the spatial relationship between proliferation, vasculature, and hypoxia and to examine the microregional effects. Within 1 day after administration of 240 mg/kg of gemcitabine, proliferation throughout the tumor was completely inhibited. Over time, a reemergence of dividing cells occurred in relation to the distance from vasculature. Microregional analysis revealed that cells located distal to vasculature commenced cycling sooner than cells located proximal to vasculature. A similar trend was seen after multiple doses of gemcitabine (40 mg/kg on days 1, 4, 7, and 10). The possibility that the effect of gemcitabine could be attributed to changes in oxygenation was discounted after examining the vessel perfusion and patterns of hypoxia. The effect of gemcitabine was examined in multilayered cell culture, and at doses &lt;30 μmol/L, a gradient in proliferation between the exposed and unexposed sides was observed. We show a differential effect on cell proliferation in relation to vasculature and conclude that cells distal to blood vessels are less affected by gemcitabine probably because of limited penetration.
Hepatocyte Growth Factor/Scatter Factor Differentially Regulates Expression of Proangiogenic Factors through Egr-1 in Head and Neck Squamous Cell Carcinoma
Authors: Worden Brian , Yang Xin Ping , Lee Tin Lap , Bagain Lorena , Yeh Ning T. , Cohen Joshua G. , Van Waes Carter , Chen Zhong 
Published: September 2005

Abstract
Hepatocyte growth factor/scatter factor (HGF) and the angiogenesis factors platelet-derived growth factors (PDGF), vascular endothelial growth factor (VEGF), and interleukin-8 (IL-8) are found in elevated concentrations in serum or tumor tissue of patients with head and neck squamous cell carcinomas (HNSCC), suggesting these factors may be coregulated. A cDNA microarray analysis for HGF-inducible genes revealed that HGF also modulates PDGFA expression, a gene recently shown to be inducible by the transcription factor, early growth response-1 (Egr-1). In the present study, we investigated the potential role of HGF-induced Egr-1 in expression of PDGF, VEGF, and IL-8. HGF induced expression of all three factors and Egr-1 expression and DNA-binding activity. The analysis of promoter sequences showed putative Egr-1 binding sites in the PDGFA or VEGF but not in the IL-8 promoter, and HGF-induced Egr-1–binding activity was confirmed by chromatin immunoprecipitation (ChIP) assay. The maximal basal and HGF-induced promoter activity for the PDGFA gene existed within −630 bp of the promoter region, and overexpression of Egr-1 significantly increased such activity. Consistent with this, expression of PDGFA and VEGF but not IL-8 showed corresponding differences with Egr-1 expression in HNSCC tumor specimens and were strongly suppressed by transfection of Egr-1–antisense or small interference RNA (siRNA) oligonucleotides. HGF-induced expression of Egr-1, PDGFA, and VEGF was suppressed by pharmacologic and siRNA inhibitors of mitogen-activated protein kinase kinase 1/2 (MEK1/2) and protein kinase C (PKC) pathways. We conclude that the HGF-induced activation of transcription factor Egr-1 by MEK1/2- and PKC-dependent mechanisms differentially contributes to expression of PDGF and VEGF, which are important angiogenesis factors and targets for HNSCC therapy.
Inverse Correlation between Cyclin A1 Hypermethylation and p53 Mutation in Head and Neck Cancer Identified by Reversal of Epigenetic Silencing
Authors: Tokumaru Yutaka , Yamashita Keishi , Osada Motonobu , Nomoto Shuji , Sun Dong-Il , Xiao Yan , Hoque Mohammad Obaidul , Westra William H. , Califano Joseph A. , Sidransky David 
Published: September 2005

AbstractAberrant promoter hypermethylation of tumor suppressor genes is proposed to be a common feature of primary cancer cells. We recently developed a pharmacological unmasking microarray approach to screen unknown tumor suppressor gene candidates epigenetically silenced in human cancers. In this study, we applied this method to identify such genes in head and neck squamous cell carcinoma (HNSCC). We identified 12 novel methylated genes in HNSCC cell lines, including PGP9.5, cyclin A1, G0S2, bone-morphogenetic protein 2A, MT1G, and neuromedin U, which showed frequent promoter hypermethylation in primary HNSCC (60%, 45%, 35%, 25%, 25%, and 20%, respectively). Moreover, we discovered that cyclin A1 methylation was inversely related to p53 mutational status in primary tumors (P = 0.015), and forced expression of cyclin A1 resulted in robust induction of wild-type p53 in HNSCC cell lines. Pharmacological unmasking followed by microarray analysis is a powerful tool to identify key methylated tumor suppressor genes and relevant pathways.
RNA Interference Reveals that Ligand-Independent Met Activity Is Required for Tumor Cell Signaling and Survival
Authors: Shinomiya Nariyoshi , Gao Chong Feng , Xie Qian , Gustafson Margaret , Waters David J. , Zhang Yu-Wen , Vande Woude George F. 
Published: September 2005

Abstract
Hepatocyte growth factor/scatter factor-Met signaling has been implicated in tumor growth, invasion, and metastasis. Suppression of this signaling pathway by targeting the Met protein tyrosine kinase may be an ideal strategy for suppressing malignant tumor growth. Using RNA interference technology and adenovirus vectors carrying small-interfering RNA constructs (Ad Met small-interfering RNA) directed against mouse, canine, and human Met, we can knock down c-met mRNA. We show a dramatic dependence on Met in both ligand-dependent and ligand-independent mouse, canine, and human tumor cell lines. Mouse mammary tumor (DA3) cells and Met-transformed NIH3T3 (M114) cells, as well as both human and canine prostate cancer (PC-3 and TR6LM, human sarcoma (SK-LMS-1), glioblastoma (DBTRG), and gastric cancer (MKN45) cells, all display a dramatic reduction of Met expression after infection with Ad Met small-interfering RNA. In these cells, we observe suppression of tumor cell growth and viability in vitro as well as inhibition of hepatocyte growth factor/scatter factor-mediated scattering and invasion in vitro, whether Met activation was ligand dependent or not. Importantly, Ad Met small-interfering RNA led to apoptotic cell death in many of the tumor cell lines, especially DA3 and MKN45, but did not adversely affect MDCK canine kidney cells. Met small-interfering RNA also abrogated downstream Met signaling to molecules such as Akt and p44/42 mitogen-activated protein kinase. We further show that intratumoral infection with c-met small-interfering RNA adenovirus results in a substantial reduction in tumor growth. Thus, Met small-interfering RNA adenoviruses are reliable tools for studying Met function and raise the possibility of their application for cancer therapy.
In Vivo
Flow Cytometry
Authors: Georgakoudi Irene , Solban Nicolas , Novak John , Rice William L. , Wei Xunbin , Hasan Tayyaba , Lin Charles P. 
Published: September 2005

Abstract
The fate of circulating tumor cells is an important determinant of their ability to form distant metastasis. Here, we demonstrate the use of in vivo flow cytometry as a powerful new method for detecting quantitatively circulating cancer cells. We specifically examine the circulation kinetics of two prostate cancer cell lines with different metastatic potential in mice and rats. We find that the cell line and the host environment affect the circulation kinetics of prostate cancer cells, with the intrinsic cell line properties determining the initial rate of cell depletion from the circulation and the host affecting cell circulation at later time points.
Increased Expression of Metallothionein Is Associated with Irinotecan Resistance in Gastric Cancer
Authors: Chun Jong Ho , Kim Hark Kyun , Kim Eugene , Kim In-Hoo , Kim Ju Han , Chang Hee Jin , Choi Il Ju , Lim Hyeong-Seok , Kim Il-Jin , Kang Hio Chung , Park Jae-Hyun , Bae Jae-Moon , Park Jae-Gahb 
Published: September 2005

Abstract
To gain insight into clinically relevant mechanisms of irinotecan resistance, we undertook oligonucleotide microarray analyses on paired malignant effusion samples obtained from eight gastric cancer patients treated with weekly irinotecan. Pretreatment and posttreatment (48 h) effusion samples were obtained for each patient, and the change in expression profile was compared between clinical responders and nonresponders. When differences in the expression of genes were examined using SAM (Significance Analysis of Microarrays) software, five isoforms of the metallothionein family were identified to have significantly higher signal log ratios in five nonresponders, compared with three responders. Compared with control cells, metallothionein 1X (MT1X)-transfected AGS cells showed a 1.4-fold higher irinotecan IC50 by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and tended to form more colonies. These findings collectively suggest that irinotecan-induced up-regulation of metallothionein might be associated with irinotecan resistance in patients with gastric cancer, although it remains to be confirmed in a larger data set.
Chemopreventive
n
-3 Polyunsaturated Fatty Acids Reprogram Genetic Signatures during Colon Cancer Initiation and Progression in the Rat
Authors: Davidson Laurie A. , Nguyen Danh V. , Hokanson Regina M. , Callaway Evelyn S. , Isett Robert B. , Turner Nancy D. , Dougherty Edward R. , Wang Naisyin , Lupton Joanne R. , Carroll Raymond J. , Chapkin Robert S. 
Published: September 2005

Abstract
The mechanisms by which n-3 polyunsaturated fatty acids (PUFAs) decrease colon tumor formation have not been fully elucidated. Examination of genes up- or down-regulated at various stages of tumor development via the monitoring of gene expression relationships will help to determine the biological processes ultimately responsible for the protective effects of n-3 PUFA. Therefore, using a 3 × 2 × 2 factorial design, we used Codelink DNA microarrays containing ∼9000 genes to help decipher the global changes in colonocyte gene expression profiles in carcinogen-injected Sprague Dawley rats. Animals were assigned to three dietary treatments differing only in the type of fat (corn oil/n-6 PUFA, fish oil/n-3 PUFA, or olive oil/n-9 monounsaturated fatty acid), two treatments (injection with the carcinogen azoxymethane or with saline), and two time points (12 hours and 10 weeks after first injection). Only the consumption of n-3 PUFA exerted a protective effect at the initiation (DNA adduct formation) and promotional (aberrant crypt foci) stages. Importantly, microarray analysis of colonocyte gene expression profiles discerned fundamental differences among animals treated with n-3 PUFA at both the 12 hours and 10-week time points. Thus, in addition to demonstrating that dietary fat composition alters the molecular portrait of gene expression profiles in the colonic epithelium at both the initiation and promotional stages of tumor development, these findings indicate that the chemopreventive effect of fish oil is due to the direct action of n-3 PUFA and not to a reduction in the content of n-6 PUFA.
Anti–HER-2/neuImmune Responses Are Induced before the Development of Clinical Tumors but Declined following Tumorigenesis in HER-2/neuTransgenic Mice
Authors: Takeuchi Noritami , Hiraoka Shin-ichiroh , Zhou Xu-Yu , Nagafuku Masakazu , Ono Shiro , Tsujimura Takahiro , Nakazawa Mitsuhiro , Yura Yoshiaki , Hamaoka Toshiyuki , Fujiwara Hiromi 
Published: September 2005

AbstractHER-2/neu oncogene products have been implicated as a potential target of T cell–mediated immune responses to HER-2/neu–induced tumors. Using HER-2/neu transgenic mice (oncomice), we investigated whether, and if so how, anti–HER-2/neu immune responses are induced and modulated in these oncomice from birth to tumor initiation. Female oncomice carrying the activated HER-2/neu oncogene displayed apparent hyperplasia in mammary glands at 10 weeks of age and developed mammary carcinomas around an average age of 26 weeks. Unfractionated spleen cells from 10- to 15-week-old oncomice that were cultured without any exogenous stimuli exhibited cytotoxicity against the F31 tumor cell line established from an HER-2/neu–induced mammary carcinoma mass. The final antitumor effectors were a macrophage lineage of cells. However, this effector population was activated, depending on the stimulation of oncomouse CD4+ T cells with oncomouse-derived antigen-presenting cell (APC) alone or with wild-type mouse APC in the presence of F31 membrane fractions, suggesting the presence of HER-2/neu–primed CD4+ T cells and HER-2/neu–presenting APC in 10- to 15-week-old oncomice. These antitumor cytotoxic responses were detected at ∼5 weeks of age and peaked at age 10 to 15 weeks. However, the responses then declined at tumor-bearing stages in which the expression of target proteins could progressively increase. This resulted from the dysfunction of CD4+ T cells but not of APC or effector macrophages. These results indicate that an anti–HER-2/neu CD4+ T cell–mediated immune response was generated at the pretumorigenic stage but did not prevent tumorigenesis and declined after the development of clinical tumors.
Apoptosis Resistance of MCF-7 Breast Carcinoma Cells to Ionizing Radiation Is Independent of p53 and Cell Cycle Control but Caused by the Lack of Caspase-3 and a Caffeine-Inhibitable Event
Authors: Essmann Frank , Engels Ingo H. , Totzke Gudrun , Schulze-Osthoff Klaus , Jänicke Reiner U. 
Published: September 2005

Abstract
We have shown previously that ionizing radiation (IR) induces a persistent G2-M arrest but not cell death in MCF-7 breast carcinoma cells that harbor functional p53 but lack caspase-3. In the present study, we investigated the mechanisms of apoptosis resistance and the roles of p53, caspase-3, and cell cycle arrest in IR-induced apoptosis. The methylxanthine caffeine and the staurosporine analog UCN-01, which can inhibit ATM and Chk kinases, efficiently abrogated the IR-induced G2-M arrest and induced mitochondrial activation as judged by the loss of the mitochondrial membrane potential and the release of cytochrome c and Smac/Diablo. However, despite these proapoptotic alterations, cell death and activation of the initiator caspase-9 were not induced in MCF-7 cells but were interestingly only observed after reexpression of caspase-3. Sensitization to IR-induced apoptosis by caffeine or UCN-01 was abrogated neither by cycloheximide nor by pifithrin-α, an inhibitor of the transcriptional activity of p53. Furthermore, suppression of p53 by RNA interference could not prevent caffeine- and IR-induced mitochondrial alterations and apoptosis but resulted in an even more pronounced G2-M arrest. Collectively, our results clearly show that the resistance of MCF-7 cells to IR-induced apoptosis is caused by two independent events; one of them is a caffeine- or UCN-01–inhibitable event that does not depend on p53 or a release of the G2-M arrest. The second event is the loss of caspase-3 that surprisingly seems essential for a fully functional caspase-9 pathway, even despite the previous release of mitochondrial proapoptotic proteins.
Potent Tumor-Specific Immunity Induced by an
In vivo
Heat Shock Protein-Suicide Gene–Based Tumor Vaccine
Authors: Ren Wenhong , Strube Randy , Zhang Xiaoqing , Chen Si-Yi , Huang Xue F. 
Published: September 2005

Abstract
Tumor cells harbor a repertoire of unique, mutated antigens and shared self-antigens but generally are incapable of provoking an effective immune response, likely because of inadequate antigen presentation by professional antigen-presenting cells. Heat shock proteins (HSPs) play important roles in eliciting innate and adaptive immunity by chaperoning peptides for antigen presentation and providing endogenous danger signaling. Although effective in inducing tumor-specific immunity in mice and in some clinical trials, tumor-derived HSPs have many limitations like vaccines, such as the technical difficulty of ex vivo preparation of adequate quantities of HSPs from the resected tumors of individual patients. Here we have developed an in vivo HSP-suicide gene tumor vaccine by generating a recombinant replication-defective adenovirus (Ad-HT) that coexpresses HSP70 and a herpes simplex virus thymidine kinase suicide gene. The combination of HSP70 overexpression in situ and tumor killing by thymidine kinase/ganciclovir treatment, but neither strategy alone, provoked potent systemic antitumor activities after intratumor injection of Ad-HT. Tumor-specific CD4+ and CD8+ T-cell responses were induced by Ad-HT intratumor injection. CD11c+ dendritic cells (DCs) isolated from mice treated with Ad-HT were able to prime tumor-specific CTLs. Collectively, these results indicate that the combination of tumor killing by activation of a suicide gene to release tumor antigens and in situ HSP70 overexpression to enhance DC antigen presentation overcomes host immune tolerance to tumor antigens, leading to the induction of potent antitumor immunity. Our findings may have broad relevance to the use of the in vivo HSP/suicide gene tumor vaccine in therapy for human solid tumors.
DNA Damage, Repair, and Mutation Induction by (+)-
Syn
and (−)-
Anti
-Dibenzo[
a,l
]Pyrene-11,12-Diol-13,14-Epoxides in Mouse Cells
Authors: Yoon Jung-Hoon , Besaratinia Ahmad , Feng Zhaohui , Tang Moon-shong , Amin Shantu , Luch Andreas , Pfeifer Gerd P. 
Published: September 2005

Abstract
Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental carcinogens. PAHs are classified into bay and fjord region compounds according to structural differences in the molecule region where enzymatic epoxidation occurs. Dibenzo[a,l]pyrene (DB[a,l]P), one of the fjord region compounds, has been demonstrated to be the most carcinogenic PAH known to date. DB[a,l]P is activated to fjord region (+)-syn and (−)-anti-11,12-dihydroxy-13,14-epoxy-11,12,13,14-tetrahydrodibenzo[a,l]pyrene (DB[a,l]PDE) metabolites. In this study, we analyzed mutagenesis induced by (+)-syn- and (−)-anti-DB[a,l]PDE at the cII transgene in Big-Blue mouse cells. The mutant frequency of untreated cells (background level) was 6.53 × 10−5. This level increased 3.7-fold for 20 nmol/L, 5.3-fold for 50 nmol/L, and 7.9-fold for 100 nmol/L (+)-syn-DB[a,l]PDE, respectively. In the case of (−)-anti-DB[a,l]PDE it increased 4.5-fold for 20 nmol/L, 6.7-fold for 50 nmol/L, and 10.6-fold for 100 nmol/L, respectively, indicating that (−)-anti-DB[a,l]PDE is slightly more mutagenic than (+)-syn-DB[a,l]PDE. The mutational spectra of (+)-syn- and (−)-anti-DB[a,l]PDE were quite similar except for several hotspots, specific for either (+)-syn-DB[a,l]PDE or (−)-anti-DB[a,l]PDE. The most frequently induced mutations were A to T transversions, which were 43.9% for (+)-syn- and 38.8% for (−)-anti-DB[a,l]PDE. In addition, G to T transversions were induced significantly, at frequencies of 18.5% by (+)-syn- and 18.1% by (−)-anti-DB[a,l]PDE. Using UvrABC cleavage and ligation-mediated PCR or the terminal transferase-dependent PCR method, we have determined DB[a,l]PDE-DNA adduct formation sites and repair rates in carcinogen-exposed cells. The mutation hotspots coincided with sites of strong adduct formation, but not all of the adduct hotspots were mutational hotspots. Slow adduct removal occurred for both (+)-syn- and (−)-anti-DB[a,l]PDE adducts over a time period of up to 72 hours. The data suggest that, although the (−)-anti-isomer is slightly more mutagenic, DNA adducts of both DB[a,l]PDE stereoisomers may have similar biological properties. We discuss the implications of these findings for human cancer mutagenesis.
Preneoplastic Markers of Hepatitis B Virus-Associated Hepatocellular Carcinoma
Authors: Hann Hie-Won L. , Lee Jungmin , Bussard Anne , Liu Catherine , Jin Yongri R. , Guha Koel , Clayton Marcia M. , Ardlie Kristin , Pellini Michael J. , Feitelson Mark A. 
Published: September 2005

Abstract
Hepatitis B virus (HBV) carriers are at high risk for the development of hepatocellular carcinoma (HCC), but there are no reliable markers that will identify such high-risk carriers. The objective of this work is to identify serologic markers that may indicate the early presence of HCC. Since HBV-encoded X antigen (HBxAg) likely contributes to HCC by up- or down-regulation of host gene expression, X positive and negative HepG2 cells were made and subjected to cDNA subtraction. When specific ELISAs were constructed measuring differentially expressed antigens and corresponding antibodies, antibodies to several differentially expressed genes were detected. In cross-sectional and longitudinal studies, antibodies were predominantly present in patients with HBV-associated cirrhosis and HCC, but not in most carriers with hepatic inflammation alone or without active liver disease. Antibodies were also present in patients with hepatitis C virus (HCV)-related HCC, but rarely detected in sera from uninfected individuals, those with tumors other than HCC, or those with drug-induced hepatitis. Statistical analysis showed that HCC patients with four or more antibodies detectable before the appearance of HCC had decreased survival, suggesting that these markers may reflect stepwise hepatocarcinogenesis. Hence, these antibodies may serve as preneoplastic markers for HCC in HBV carriers with chronic liver disease, and may be identified by a simple blood test.