bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visualization of Hypoxia in Microscopic Tumors by Immunofluorescent Microscopy
Authors: Li Xiao-Feng , Carlin Sean , Urano Muneyasu , Russell James , Ling C. Clifton , O'Donoghue Joseph A. 
Published: August 2007

Abstract
Tumor hypoxia is commonly observed in primary solid malignancies but the hypoxic status of subclinical micrometastatic disease is largely unknown. The distribution of hypoxia in microscopic tumors was studied in animal models of disseminated peritoneal disease and intradermal (i.d.) growing tumors. Tumors derived from human colorectal adenocarcinoma cell lines HT29 and HCT-8 ranged in size from a few hundred microns to several millimeters in diameter. Hypoxia was detected by immunofluorescent visualization of pimonidazole and the hypoxia-regulated protein carbonic anhydrase 9. Tumor blood perfusion, cellular proliferation, and vascularity were visualized using Hoechst 33342, bromodeoxyuridine, and CD31 staining, respectively. In general, tumors of &lt;1 mm diameter were intensely hypoxic, poorly perfused, and possessed little to no vasculature. Larger tumors (∼1–4 mm diameter) were well perfused with widespread vasculature and were not significantly hypoxic. Patterns of hypoxia in disseminated peritoneal tumors and i.d. tumors were similar. Levels of hypoxia in microscopic peritoneal tumors were reduced by carbogen breathing. Peritoneal and i.d. tumor models are suitable for studying hypoxia in microscopic tumors. If the patterns of tumor hypoxia in human patients are similar to those observed in these animal experiments, then the efficacy of systemic treatments of micrometastatic disease may be compromised by hypoxic resistance. [Cancer Res 2007;67(16):7646–52]
The Role of Glycogen Synthase Kinase 3β in the Transformation of Epidermal Cells
Authors: Ma Cuiling , Wang Jian , Gao Ying , Gao Tian-Wen , Chen Gang , Bower Kimberly A. , Odetallah Mohammed , Ding Min , Ke Zunji , Luo Jia 
Published: August 2007

Abstract
Glycogen synthase kinase 3β (GSK3β) is a multifunctional serine/threonine kinase. We showed that the expression of GSK3β was drastically down-regulated in human cutaneous squamous cell carcinomas and basal cell carcinomas. Due to its negative regulation of many oncogenic proteins, we hypothesized that GSK3β may function as a tumor suppressor during the neoplastic transformation of epidermal cells. We tested this hypothesis using an in vitro model system, JB6 mouse epidermal cells. In response to epidermal growth factor (EGF) or 12-O-tetradecanoylphorbol-13-acetate (TPA), the promotion-sensitive JB6 P+ cells initiate neoplastic transformation, whereas the promotion-resistant JB6 P− cells do not. JB6 P− cells expressed much higher levels of GSK3β than JB6 P+ cells; JB7 cells, the transformed derivatives of JB6, had the least amount of GSK3β. The activity of GSK3β is negatively regulated by its phosphorylation at Ser9. EGF and TPA induced strong Ser9 phoshorylation in JB6 P+ cells, but phosphorylation was seen at a much lesser extent in JB6 P− cells. EGF and TPA-stimulated Ser9 phosphorylation was mediated by phosphoinositide-3-kinase (PI3K)/Akt and protein kinase C (PKC) pathways. Inhibition of GSK3β activation significantly stimulated activator protein-1 (AP-1) activity. Overexpression of wild-type (WT) and S9A mutant GSK3β in JB6 P+ cells suppressed EGF and TPA-mediated anchorage-independent growth in soft agar and tumorigenicity in nude mice. Overexpression of a kinase-deficient (K85R) GSK3β, in contrast, potentiated anchorage-independent growth and drastically enhanced in vivo tumorigenicity. Together, these results indicate that GSK3β plays an important role in skin tumorigenesis. [Cancer Res 2007;67(16):7756–64]
Production of Wnt Inhibitors by Myeloma Cells: Potential Effects on Canonical Wnt Pathway in the Bone Microenvironment
Authors: Giuliani Nicola , Morandi Francesca , Tagliaferri Sara , Lazzaretti Mirca , Donofrio Gaetano , Bonomini Sabrina , Sala Roberto , Mangoni Marcellina , Rizzoli Vittorio 
Published: August 2007

Abstract
Osteoblast impairment occurs within multiple myeloma cell infiltration into the bone marrow. Canonical Wnt signaling activation in osteoprogenitor cells is involved in osteoblast formation through the stabilization of dephosphorylated β-catenin and its nuclear translocation. The effects of multiple myeloma cells on Wnt signaling in human mesenchymal/osteoprogenitor cells are unclear. In 60 multiple myeloma patients checked, we found that among the Wnt inhibitors, Dickkopf-1 and secreted frizzled-related protein-3 were produced by multiple myeloma cells. However, although multiple myeloma cells or multiple myeloma bone marrow plasma affected expression of genes in the canonical Wnt signaling and inhibited β-catenin stabilization in murine osteoprogenitor cells, they failed to block the canonical Wnt pathway in human mesenchymal or osteoprogenitor cells. Consistently, Wnt3a stimulation in human osteoprogenitor cells did not blunt the inhibitory effect of multiple myeloma cells on osteoblast formation. Consequently, despite the higher Wnt antagonist bone marrow levels in osteolytic multiple myeloma patients compared with nonosteolytic ones, β-catenin immunostaining was not significantly different. Our results support the link between the production of Wnt antagonists by multiple myeloma cells and the presence of bone lesions in multiple myeloma patients but show that myeloma cells do not inhibit canonical Wnt signaling in human bone microenvironment. [Cancer Res 2007;67(16):7665–74]
Distinct ErbB-2–Coupled Signaling Pathways Promote Mammary Tumors with Unique Pathologic and Transcriptional Profiles
Authors: Schade Babette , Lam Sonya H.L. , Cernea Daniela , Sanguin-Gendreau Virginie , Cardiff Robert D. , Jung Boonim L. , Hallett Michael , Muller William J. 
Published: August 2007

Abstract
ErbB-2 overexpression and amplification occurs in 15% to 30% of human invasive breast carcinomas associated with poor clinical prognosis. Previously, we have shown that four ErbB-2/Neu tyrosine-autophosphorylation sites within the cytoplasmic tail of the receptor recruit distinct adaptor proteins and are sufficient to mediate transforming signals in vitro. Two of these sites, representing the growth factor receptor binding protein 2 (Grb2; Neu-YB) and the Src homology and collagen (Shc; Neu-YD) binding sites, can induce mammary tumorigenesis and metastasis. Here, we show that transgenic mice bearing the two other ErbB-2 autophosphorylation sites (Neu-YC and Neu-YE) develop metastatic mammary tumors. A detailed comparison of biological profiles among all Neu mutant mouse models revealed that Neu-YC, Neu-YD, and Neu-YE mammary tumors shared similar pathologic and transcriptional features. By contrast, the Neu-YB mouse model displayed a unique pathology with a high metastatic potential that correlates with a distinct transcriptional profile, including genes that promote malignant tumor progression such as metalloproteinases and chemokines. Furthermore, Neu-YB tumor epithelial cells showed abundant intracellular protein level of the chemokine CXCL12/SDF-1α, which may reflect the aggressive nature of this Neu mutant mouse model. Taken together, these findings indicate that activation of distinct Neu-coupled signaling pathways has an important impact on the biological behavior of Neu-induced tumors. [Cancer Res 2007;67(16):7579–88]
Platelet-Derived Growth Factor Receptor Regulates Myeloid and Monocytic Differentiation of HL-60 Cells
Authors: Reiterer Gudrun , Yen Andrew 
Published: August 2007

Abstract
Here, we show that the platelet-derived growth factor receptor (PDGFR) regulates myeloid and monocytic differentiation of HL-60 myeloblastic leukemia cells in response to retinoic acid (RA) and vitamin D3 (D3), respectively. Both RA and D3 decreased the expression of PDGFR-α and PDGFR-β throughout differentiation. When cells were treated with the PDGFR inhibitor AG1296 in addition to RA or D3, signs of terminal differentiation such as inducible oxidative metabolism and cell substrate adhesion were enhanced. These changes were accompanied by an increased extracellular signal-regulated kinase 1/2 activation. AG1296 also resulted in elevated expression of differentiation markers CD11b and CD66c when administered with RA or D3. Interestingly, other markers did not follow the same pattern. Cells receiving AG1296 in addition to RA or D3 showed decreased G1-G0 arrest and CD14, CD38, and CD89 expression. We thus provide evidence that certain sets of differentiation markers can be enhanced, whereas others can be inhibited by the PDGFR pathway. In addition, we found calcium levels to be decreased by RA and D3 but increased when AG1296 was given in addition to RA or D3, suggesting that calcium levels decrease during myeloid or monocytic differentiation, and elevated calcium levels can disturb the expression of certain differentiation markers. [Cancer Res 2007;67(16):7765–71]
Regulation of PTEN Expression in Intestinal Epithelial Cells by c-Jun NH2-Terminal Kinase Activation and Nuclear Factor-κB Inhibition
Authors: Wang Qingding , Zhou Yuning , Wang Xiaofu , Chung Dai H. , Evers B. Mark 
Published: August 2007

Abstract
The tumor suppressor protein phosphatase and tensin homologue deleted on chromosome ten (PTEN) plays an important role in intestinal cell proliferation and differentiation and tumor suppression by antagonizing phosphatidylinositol 3-kinase. Despite its importance, the molecular mechanisms regulating PTEN expression are largely undefined. Here, we show that treatment of the colon cancer cell line HT29 with the differentiating agent sodium butyrate (NaBT) increased PTEN protein and mRNA expression and induced c-Jun NH2-terminal kinase (JNK) activation. Inhibition of JNK by chemical or genetic methods attenuated NaBT-induced PTEN expression. In addition, our findings showed a cross-talk between nuclear factor κB (NF-κB) and JNK with respect to PTEN regulation. Overexpression of the NF-κB superrepressor increased PTEN expression and JNK activity, whereas overexpression of the p65 NF-κB subunit reduced both basal and NaBT-mediated JNK activation and PTEN expression. Moreover, we showed that overexpression of PTEN or treatment with NaBT increased expression of the cyclin-dependent kinase inhibitor p27kip1 in HT29 cells; this induction was attenuated by inhibition of PTEN or JNK expression or overexpression of p65. Finally, we show a role for PTEN in NaBT-mediated cell death and differentiation. Our findings suggest that the JNK/PTEN and NF-κB/PTEN pathways play a critical role in normal intestinal homeostasis and colon carcinogenesis. [Cancer Res 2007;67(16):7773–81]
Cells with Defective p53-p21-pRb Pathway Are Susceptible to Apoptosis Induced by p84N5 via Caspase-6
Authors: Garner Elizabeth , Martinon Fabio , Tschopp Jurg , Beard Peter , Raj Kenneth 
Published: August 2007

Abstract
Adeno-associated virus (AAV) infection triggers a DNA damage response in the cell. This response is not induced by viral proteins but by virtue of the structure of AAV ssDNA being recognized by the cell as damaged DNA. The consequence of this is the killing of cells lacking p53 activity. We have observed that cells that lack p21 or pRb activity are also sensitive to AAV-induced cell death. We report that cells respond to AAV infection by activating two DNA damage signaling cascades. The first activates the p84N5 protein, which in turn activates caspase-6, leading to cell death. The second cascade activates the p53-21-pRb pathway, which inhibits activation of the p84N5 protein and thus prevents cell death. The result of the antagonistic interaction between these two pathways is that cells that do not exhibit functional p53-p21-pRb signaling undergo apoptosis as a consequence of AAV infection. Cells with a functional p53-21-pRb pathway are refractory to AAV-induced cell death. These results show that p53, although a proapoptotic protein, together with pRb and p21 proteins, is a member of an antiapoptotic cellular mechanism. As such, these experiments reveal features that may be exploited to specifically kill cells that lack the p53-p21-pRb pathway, such as cancer cells. The use of AAV to expose these subtle characteristics of intracellular signaling further highlights the advantages of using viruses as precision tools with which to address questions of cell biology. [Cancer Res 2007;67(16):7631–7]
Zonal Heterogeneity for Gene Expression in Human Pancreatic Carcinoma
Authors: Nakamura Toru , Kuwai Toshio , Kitadai Yasuhiko , Sasaki Takamitsu , Fan Dominic , Coombes Kevin R. , Kim Sun-Jin , Fidler Isaiah J. 
Published: August 2007

Abstract
Using Affymetrix HG-U133 Plus 2.0 array and laser capture microdissection techniques, we determined whether different zones of the same pancreatic tumor exhibited differential expression of genes. Human L3.6pl pancreatic cancer cells were implanted into the pancreas of nude mice. Three weeks later when tumors were 7 to 9 mm in diameter, gene expression patterns in tumor cells within the central and peripheral zones were compared, and 1,222 genes showed statistically significant differences. Bioinformatic functional analysis revealed that 346 up-regulated genes in the peripheral zone were related to cytoskeleton organization and biogenesis, cell cycle, cell adhesion, cell motility, DNA replication, localization, integrin-mediated signaling pathway, development, morphogenesis, and IκB kinase/nuclear factor-κB cascade; 876 up-regulated genes in the central zone were related to regulation of cell proliferation, regulation of transcription, transmembrane receptor protein tyrosine kinase signaling pathways, response to stress, small GTPase-mediated signal transduction, hexose metabolism, cell death, response to external stimulus, carbohydrate metabolism, and response to wounding. The reliability of the microarray results were confirmed by in situ hybridization analysis of the expression of two genes. Collectively, the data showed zonal heterogeneity for gene expression profiles in tumors and suggest that characterization of zonal gene expression profiles is essential if microarray analyses of genetic profiles are to produce reproducible data, predict disease prognosis, and allow design of specific therapeutics. [Cancer Res 2007;67(16):7597–604]
Erythropoietin and Erythropoietin Receptor Coexpression Is Associated with Poor Survival in Stage I Non–Small Cell Lung Cancer
Authors: Saintigny Pierre , Besse Benjamin , Callard Patrice , Vergnaud Anne-Claire , Czernichow Sébastien , Colombat Magali , Girard Philippe , Validire Pierre , Breau Jean-Luc , Bernaudin Jean-François , Soria Jean-Charles 
Published: August 2007

AbstractPurpose: This study was designed to evaluate the prognostic effect of erythropoietin (EPO) and EPO receptor (EPO-R) expression in stage I non–small cell lung cancer (NSCLC) patients.Experimental Design: EPO and EPO-R expression in 158 tumor samples from resected stage I NSCLC was evaluated using immunohistochemistry and tissue array technology.Results: EPO-R and EPO were highly expressed in 20.9% and 35.4% of tumors, respectively. High EPO-R expression compared with negative or low-level expression was associated with a poor 5-year disease-specific survival (60.6% versus 80.8%; P = 0.01, log-rank test). High EPO expression compared with negative and low-level expression was associated with a trend toward a poor 5-year disease-specific survival (69.6% versus 80.4%; P = 0.13, log-rank test). A high level of EPO-R and EPO coexpression was associated with a poor 5-year disease-specific survival compared with other groups of patients (50.0% versus 80.0% survival at the end of follow-up; P = 0.005, log-rank test). In multivariate analysis for disease-specific survival, high-level EPO-R and EPO coexpression was an independent prognostic factor for disease-specific survival (hazard ratio, 2.214; 95% confidence interval, 1.012-4.848; P = 0.046).Conclusion: These results establish the pejorative prognostic value of EPO and EPO-R expression in early-stage resected NSCLC and suggest a potential paracrine and/or autocrine role of endogenous EPO in NSCLC aggressiveness.
Enhanced Antitumor Effect of Combined Triptolide and Ionizing Radiation
Authors: Wang Wei , Yang Shanmin , Su Ying , Xiao Zhenyu , Wang Chunyou , Li Xinfeng , Lin Ling , Fenton Bruce M. , Paoni Scott F. , Ding Ivan , Keng Peter , Okunieff Paul , Zhang Lurong 
Published: August 2007

AbstractPurpose: The lack of effective treatment for pancreatic cancer results in a very low survival rate. This study explores the enhancement of the therapeutic effect on human pancreatic cancer via the combination of triptolide and ionizing radiation (IR).Experimental Design: In vitro AsPC-1 human pancreatic cancer cells were treated with triptolide alone, IR alone, or triptolide plus IR. Cell proliferation was analyzed with sulforhodamine B (SRB) method and clonogenic survival; comparison of apoptosis induced by the above treatment was analyzed by annexin V–propidium iodide (PI) staining. Furthermore, the expression of apoptotic pathway intermediates was measured by the assay of caspase activity and Western blot. Mitochondrial transmembrane potential was determined by JC-1 assay. In vivo, AsPC-1 xenografts were treated with 0.25 mg/kg triptolide, 10 Gy IR, or triptolide plus IR. The tumors were measured for volume and weight at the end of the experiment. Tumor tissues were tested for terminal nucleotidyl transferase–mediated nick end labeling (TUNEL) and immunohistochemistry.Results: The combination of triptolide plus IR reduced cell survival to 21% and enhanced apoptosis, compared with single treatment. In vivo, tumor growth of AsPC-1 xenografts was reduced further in the group treated with triptolide plus IR compared with single treatment. TUNEL and immunohistochemistry of caspase-3 cleavage in tumor tissues indicated that the combination of triptolide plus IR resulted in significantly enhanced apoptosis compared with single treatments.Conclusions: Triptolide in combination with ionizing radiation produced synergistic antitumor effects on pancreatic cancer both in vitro and in vivo and seems promising in the combined modality therapy of pancreatic cancer.
Comprehensive Analysis of Copy Number and Allele Status Identifies Multiple Chromosome Defects Underlying Follicular Lymphoma Pathogenesis
Authors: Ross Charles W. , Ouillette Peter D. , Saddler Chris M. , Shedden Kerby A. , Malek Sami N. 
Published: August 2007

Abstract
Purpose: Follicular lymphoma (FL) constitutes the second most common non-Hodgkin's lymphoma in the Western world. The clinical course is variable and only in part explained by known tumor-intrinsic or -extrinsic factors. FL carries the hallmark chromosomal translocation t(14;18), deregulating the expression of Bcl-2, but this is not sufficient to explain either FL biology or clinical behavior.
Experimental Design: We have employed high-density genomic profiling technology using the Affymetrix 50K-XbaI oligonucleotide single nucleotide polymorphism–chip platform to interrogate the genomes of 58 fluorescence-activated cell–sorted (FACS) FL specimens for chromosomal copy number changes and 46 specimens for loss of heterozygosity (LOH).
Results: We report (a) previously unknown high-frequency copy-neutral LOH (uniparental disomy) in FL on chromosomes 1p (∼50%) and 6p (∼30%); (b) that del6q is complex, as reported, with at least two regions of minimal common loss at 6q13-15 and 6q23-24, and that in addition, ∼8% of FL specimens contain a homozygous deletion at 6q23.3-24.1 that spans the negative NFκB regulator A20 and the p53 apoptosis effector PERP; (c) that combined analysis of chromosome 17p for LOH, copy number, and p53 mutations shows that most p53 mutations in FL do not involve del17p. Finally, we map high-frequency LOH with and without copy loss on chromosomes 9p, 10q, and 16p and genomic gains on 2p15-16 and 8q24.22-24.3.
Conclusions: This comprehensive description of the pathologic anatomy of the FL genome uncovers novel genetic lesions and should aid with identification of genes relevant to FL biology and clinical behavior.
Human Breast Cancer Cells Selected for Resistance to Trastuzumab In vivo Overexpress Epidermal Growth Factor Receptor and ErbB Ligands and Remain Dependent on the ErbB Receptor Network
Authors: Ritter Christoph A. , Perez-Torres Marianela , Rinehart Cammie , Guix Marta , Dugger Teresa , Engelman Jeffrey A. , Arteaga Carlos L. 
Published: August 2007

Abstract
Purpose: We have investigated mechanisms of acquired resistance to the HER2 antibody trastuzumab in BT-474 human breast cancer cells.
Experimental Design: BT-474 xenografts established in athymic nude mice were eliminated by trastuzumab. Continuous cell lines (HR for Herceptin resistant) were generated from tumors that recurred in the presence of continuous antibody therapy.
Results: The isolated cells behaved resistant to trastuzumab in culture as well as when reinjected into nude mice. They retained HER2 gene amplification and trastuzumab binding and were exquisitely sensitive to peripheral blood mononuclear cells ex vivo in the presence of the antibody. The HR cells exhibited higher levels of phosphorylated epidermal growth factor receptor (EGFR) and EGFR/HER2 heterodimers. Phosphorylation of HER2 in HR cells was inhibited by the EGFR tyrosine kinase inhibitors erlotinib and gefitinib. Gefitinib also inhibited the basal association of p85 with phosphorylated HER3 in HR cells. Both inhibitors as well as the dual EGFR/HER2 inhibitor, lapatinib, induced apoptosis of the HR cells in culture. Growth of established HR5 xenografts was inhibited by erlotinib in vivo. In addition, the HR cells overexpressed EGFR, transforming growth factor α, heparin-binding EGF, and heregulin RNAs compared with the parental trastuzumab-sensitive cells.
Conclusions: These results are consistent with the inability of trastuzumab to block the heterodimerization of HER2 and suggest that amplification of ligand-induced activation of ErbB receptors is a plausible mechanism of acquired resistance to trastuzumab that should be investigated in primary mammary cancers.