bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nitric Oxide–Induced Apoptosis in Lymphoblastoid and Fibroblast Cells Dependent on the Phosphorylation and Activation of p53
Authors: McLaughlin Laura M. , Demple Bruce 
Published: September 2005

Abstract
When nitric oxide (NO) is produced at micromolar concentrations, as during inflammation, exposure to surrounding cells is potentially cytotoxic. The NO-dependent signaling pathways that initiate cell death are thought to involve the tumor suppressor protein p53, but the degree to which this factor contributes to NO-induced cell death is less clear. Various reports either confirm or negate a role for p53 depending on the cell type and NO donor used. In this study, we have used several pairs of cell lines whose only differences are the presence or absence of p53, and we have treated these cell lines with the same NO donor, spermineNONOate (SPER/NO). Treatment with SPER/NO induced such apoptotic markers as DNA fragmentation, nuclear condensation, poly(ADP-ribose) polymerase cleavage, cytochrome c release, and Annexin V staining. p53 was required for at least 50% of SPER/NO-induced apoptotic cell death in human lymphoblastoid cells and for almost all in primary and E1A-tranformed mouse embryonic fibroblasts, which highlights the possible importance of DNA damage for apoptotic signaling in fibroblasts. In contrast, p53 did not play a significant role in NO-induced necrosis. NO treatment also induced the phosphorylation of p53 at Ser15; pretreatment with phosphoinositide-3 kinase (PI3K) family inhibitors, wortmannin, LY294002, and caffeine, blocked such phosphorylation, but the p38 mitogen-activated protein kinase inhibitor, SB203580, did not. Pretreatment with the PI3K family inhibitors also led to a switch from NO-induced apoptosis to necrosis, which implicates a PI3K-related kinase such as ataxia telangiectasia mutated (ATM) or ATR (ATM and Rad3 related) in p53-dependent NO-induced apoptosis.
Signal Transducer and Activator of Transcription 3 Is a Key Regulator of Keratinocyte Survival and Proliferation following UV Irradiation
Authors: Sano Shigetoshi , Chan Keith Syson , Kira Masahiro , Kataoka Ken , Takagi Satoshi , Tarutani Masahito , Itami Satoshi , Kiguchi Kaoru , Yokoi Masayuki , Sugasawa Kaoru , Mori Toshio , Hanaoka Fumio , Takeda Junji , DiGiovanni John 
Published: September 2005

Abstract
UVB irradiation of signal transducer and activator of transcription 3 (Stat3)–deficient keratinocytes resulted in a high incidence of apoptosis compared with controls. Conversely, forced expression of Stat3 desensitized keratinocytes to UVB-induced apoptosis. Upon UVB exposure, keratinocyte Stat3 was rapidly dephosphorylated, followed by decreases of both Stat3 mRNA and protein levels in a p53-independent manner. Vanadate treatment reversed the UVB-induced down-regulation of Stat3 and generation of apoptotic keratinocytes, suggesting the involvement of a tyrosine phosphatase. Furthermore, Stat3 was required for UVB-induced proliferation of follicular keratinocytes, leading to epidermal thickening. Finally, constitutive activation of Stat3 was observed in UVB-induced squamous cell carcinomas of either mice or human origin. These data suggest that Stat3 is required for survival and proliferation of keratinocytes following UVB exposure and that Stat3 is tightly regulated as part of a novel protective mechanism against UVB-induced skin cancer.
Stromal Cell–Derived Factor-1α and CXCR4 Expression in Hemangioblastoma and Clear Cell-Renal Cell Carcinoma: von Hippel-Lindau Loss-of-Function Induces Expression of a Ligand and Its Receptor
Authors: Zagzag David , Krishnamachary Balaji , Yee Herman , Okuyama Hiroaki , Chiriboga Luis , Ali M. Aktar , Melamed Jonathan , Semenza Gregg L. 
Published: September 2005

Abstract
The genetic hallmark of hemangioblastomas and clear cell-renal cell carcinomas (CC-RCCs) is loss-of-function of the von Hippel-Lindau (VHL) tumor suppressor protein. VHL is required for oxygen-dependent degradation of hypoxia-inducible factor-1α (HIF-1α). In hemangioblastomas and CC-RCCs, HIF-1α is constitutively overexpressed leading to increased transcription of HIF-1–regulated genes, including vascular endothelial growth factor (VEGF). Because loss of VHL function is associated with increased expression of the chemokine receptor CXCR4 in CC-RCCs, we investigated the expression of HIF-1α, CXCR4, and its ligand stromal cell–derived factor-1α (SDF-1α) in hemangioblastomas and CC-RCCs. Immunohistochemistry revealed overexpression of both CXCR4 and SDF-1α within tumor cells and endothelial cells of hemangioblastomas and CC-RCCs. HIF-1α was detected in tumor cell nuclei of both hemangioblastomas and CC-RCCs. A specific ELISA showed that hemangioblastomas and CC-RCCs expressed SDF-1α protein at levels that were significantly higher than those found in normal tissue. Analysis of the VHL-null RCC line 786-0 revealed that SDF-1α mRNA levels were 100-fold higher than in a subclone transfected with the wild-type VHL gene. Expression of CXCR4 and SDF-1α mRNA was significantly decreased in HIF-1α-null compared with wild-type mouse embryo fibroblasts (MEFs). ELISA and Western blot studies for SDF-1α and CXCR4 protein expression confirmed the RNA findings in RCC lines and MEFs. These results suggest that loss-of-function of a single tumor suppressor gene can up-regulate the expression of both a ligand and its receptor, which may establish an autocrine signaling pathway with important roles in the pathogenesis of hemangioblastoma and CC-RCC.
Selective Killing of Adriamycin-Resistant (G2 Checkpoint-Deficient and MRP1-Expressing) Cancer Cells by Docetaxel
Authors: Demidenko Zoya N. , Halicka Dorota , Kunicki Jan , McCubrey James A. , Darzynkiewicz Zbigniew , Blagosklonny Mikhail V. 
Published: September 2005

Abstract
Chemotherapy of cancer is limited by toxicity to normal cells. Drug resistance further limits the therapy. Here, we investigated selective killing of drug-resistant cancer cells by antagonistic drug combinations, which can spare (because of drug antagonism) normal cells. We used paired cell lines that are resistant to Adriamycin due to either expression of MRP1 or lack of G2 checkpoints. The goal was to selectively kill Adriamycin-resistant cancer cells with Docetaxel (Taxotere), while protecting parental (Adriamycin-sensitive) cells, using cytostatic concentrations of Adriamycin. Taxotere kills cells in mitosis. Therefore, by arresting parental cells in G2, 20 to 40 ng/mL of Adriamycin prevented cell death caused by Taxotere. Also, Adriamycin prevented the effects of Taxotere in normal human lymphocytes. In contrast, Taxotere selectively killed MRP1-expressing leukemia cells, which did not undergo G2 arrest in the presence of Adriamycin. Also, in the presence of Adriamycin, HCT116-p21−/− cancer cells with a defective G2 checkpoint entered mitosis and were selectively killed by Taxotere. Finally, 20 ng/mL of Adriamycin protected normal FDC-P1 hematopoietic cells from Taxotere. Whereas parental cells were protected by Adriamycin, the mitogen-activated protein/extracellular signal-regulated kinase inhibitor PD90598 potentiated the cytotoxic effect of Taxotere selectively in Raf-1–transformed FDC-P1 leukemia cells. We propose a therapeutic strategy to prevent normal cells from entering mitosis while increasing apoptosis selectively in mitotic cancer cells.
The PKCα-D294G Mutant Found in Pituitary and Thyroid Tumors Fails to Transduce Extracellular Signals
Authors: Zhu Yimin , Dong Qihan , Tan Bee Jen , Lim Wee Guan , Zhou Shufeng , Duan Wei 
Published: September 2005

AbstractProtein kinase C (PKC) is a key regulator of cell proliferation, differentiation, and apoptosis and is one of the drug targets of anticancer therapy. Recently, a single point mutation (D294G) in PKCα has been found in pituitary and thyroid tumors with more invasive phenotype. Although the PKCα-D294G mutant is implicated in the progression of endocrine tumors, no apparent biochemical/cell biological abnormalities underlying tumorigenesis with this mutant have been found. We report here that the PKCα-D294G mutant is unable to bind to cellular membranes tightly despite the fact that it translocates to the membrane as efficiently as the wild-type PKCα upon treatment of phorbol ester. The impaired membrane binding is associated with this mutant's inability to transduce several antitumorigenic signals as it fails to mediate phorbol ester–stimulated translocation of myristoylated alanine–rich protein kinase C substrate (MARCKS), to activate mitogen-activated protein kinase and to augment melatonin-stimulated neurite outgrowth. Thus, the PKCα-D294G is a loss-of-function mutation. We propose that the wild-type PKCα may play important antitumorigenic roles in the progression of endocrine tumors. Therefore, developing selective activators instead of inhibitors of PKCα might provide effective pharmacological interventions for the treatment of certain endocrine tumors.
PCOTH, a Novel Gene Overexpressed in Prostate Cancers, Promotes Prostate Cancer Cell Growth through Phosphorylation of Oncoprotein TAF-Iβ/SET
Authors: Anazawa Yoshio , Nakagawa Hidewaki , Furihara Mutsuo , Ashida Shingo , Tamura Kenji , Yoshioka Hiroki , Shuin Taro , Fujioka Tomoaki , Katagiri Toyomasa , Nakamura Yusuke 
Published: September 2005

Abstract
Through genome-wide cDNA microarray analysis coupled with microdissection of prostate cancer cells, we identified a novel gene, prostate collagen triple helix (PCOTH), showing overexpression in prostate cancer cells and its precursor cells, prostatic intraepithelial neoplasia (PIN). Immunohistochemical analysis using polyclonal anti-PCOTH antibody confirmed elevated expression of PCOTH, a 100-amino-acid protein containing collagen triple-helix repeats, in prostate cancer cells and PINs. Knocking down PCOTH expression by small interfering RNA (siRNA) resulted in drastic attenuation of prostate cancer cell growth, and concordantly, LNCaP derivative cells that were designed to constitutively express exogenous PCOTH showed higher growth rate than LNCaP cells transfected with mock vector, suggesting the growth-promoting effect of PCOTH on prostate cancer cell. To investigate the biological mechanisms of this growth-promoting effect, we applied two-dimensional differential gel electrophoresis (2D-DIGE) to analyze the phospho-protein fractions in LNCaP cells transfected with PCOTH. We found that the phosphorylation level of oncoprotein TAF-Iβ/SET was significantly elevated in LNCaP cells transfected with PCOTH than control LNCaP cells, and these findings were confirmed by Western blotting and in-gel kinase assay. Furthermore, knockdown of endogenous TAF-Iβ expression by siRNA also attenuated viability of prostate cancer cells as well. These findings suggest that PCOTH is involved in growth and survival of prostate cancer cells thorough, in parts, the TAF-Iβ pathway, and that this molecule should be a promising target for development of new therapeutic strategies for prostate cancers.
Bcl-2 Promotes Invasion and Lung Metastasis by Inducing Matrix Metalloproteinase-2
Authors: Choi Jihyung , Choi Kyusam , Benveniste Etty N. , Hong Young-Sook , Lee Je-Ho , Kim Jhingook , Park Kyoungsook 
Published: September 2005

AbstractBcl-2 is involved in the progression of human malignancies, but the precise role and mechanism of Bcl-2 for tumor invasion and metastasis remains unclear. In this study, we have investigated the role and mechanism of Bcl-2 on tumor cell invasion and metastasis by using Bcl-2 overexpressing non–small cell lung cancer cells. Matrix metalloproteinases (MMPs) are important proteins involved in the processes of tumor invasion and metastasis. In vitro Matrigel invasion assays showed that Bcl-2 overexpression increased tumor cell invasion by 15-fold. Moreover, Bcl-2 overexpression enhanced in vivo lung metastasis by 4-fold. Consistent with its effect on invasion and metastasis, Bcl-2 overexpression induced not only MMP-2 mRNA and its protein expression, but this also activated the pro-MMP-2 protein to its active form. To explore the induction mechanism of MMP-2 by Bcl-2, we investigated the effects of Bcl-2 overexpression on MMP-2 transcriptional regulation. Nuclear run-on assays showed a 6-fold increase in the transcription rate of MMP-2 mRNA in the Bcl-2 transfectants (H157/Bcl-2) compared with that of the H157/vector control cells (H157/C). Overexpression of Bcl-2 induced the nuclear transcription factor activator protein 1 family, including the c-Jun, JunD, c-Fos, FosB, and Fra-1 proteins. Reporter assays combined with deletion mutagenesis analysis and gel shift assays showed the involvement of activator protein 1 in the activation of MMP-2 promoter activity by Bcl-2. Taken together, we have shown that Bcl-2 promotes tumor invasion and lung metastasis by inducing MMP-2 gene expression through the combined action of transcriptional and posttranslational mechanisms.
Tumor Development by Transgenic Expression of a Constitutively Active Insulin-Like Growth Factor I Receptor
Authors: Carboni Joan M. , Lee Adrian V. , Hadsell Darryl L. , Rowley Bruce R. , Lee Francis Y. , Bol David K. , Camuso Amy E. , Gottardis Marco , Greer Ann F. , Ho Ching Ping , Hurlburt Warren , Li Aixin , Saulnier Mark , Velaparthi Upender , Wang Cindy , Wen Mei-Li , Westhouse Richard A. , Wittman Mark , Zimmermann Kurt , Rupnow Brent A. , Wong Tai W. 
Published: September 2005

Abstract
The insulin-like growth factor I receptor (IGF-IR) is a transmembrane tyrosine kinase that is essential to growth and development and also thought to provide a survival signal for the maintenance of the transformed phenotype. There has been increasing interest in further understanding the role of IGF-I signaling in cancer and in developing receptor antagonists for therapeutic application. We describe herein a novel animal model that involves transgenic expression of a fusion receptor that is constitutively activated by homodimerization. Transgenic mice that expressed the activated receptor showed aberrant development of the mammary glands and developed salivary and mammary adenocarcinomas as early as 8 weeks of age. Xenograft tumors and a cell line were derived from the transgenic animals and are sensitive to inhibition by a novel small-molecule inhibitor of the IGF-IR kinase. This new model should provide new opportunities for further understanding how aberrant IGF-IR signaling leads to tumorigenesis and for optimizing novel antagonists of the receptor kinase.
Inhibition of the Phosphatidylinositol 3-Kinase/Akt/Mammalian Target of Rapamycin Pathway but not the MEK/ERK Pathway Attenuates Laminin-Mediated Small Cell Lung Cancer Cellular Survival and Resistance to Imatinib Mesylate or Chemotherapy
Authors: Tsurutani Junji , West Kip A. , Sayyah Jacqueline , Gills Joell J. , Dennis Phillip A. 
Published: September 2005

AbstractThe fact that small cell lung cancer (SCLC) is commonly incurable despite being initially responsive to chemotherapy, combined with disappointing results from a recent SCLC clinical trial with imatinib, has intensified efforts to identify mechanisms of SCLC resistance. Adhesion to extracellular matrix (ECM) is one mechanism that can increase therapeutic resistance in SCLC cells. To address whether adhesion to ECM increases resistance through modulation of signaling pathways, a series of SCLC cell lines were plated on various ECM components, and activation of two signaling pathways that promote cellular survival, the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) pathway and the mitogen-activated protein kinase kinase/extracellular signal-regulated kinase (MEK/ERK) pathway, was assessed. Although differential activation was observed, adhesion to laminin increased Akt activation, increased cellular survival after serum starvation, and caused the cells to assume a flattened, epithelial morphology. Inhibitors of the PI3K/Akt/mTOR pathway (LY294002, rapamycin) but not the MEK/ERK pathway (U0126) abrogated laminin-mediated survival. SCLC cells plated on laminin were not only resistant to serum starvation–induced apoptosis but were also resistant to apoptosis caused by imatinib. Combining imatinib with LY294002 or rapamycin but not U0126 caused greater than additive increases in apoptosis compared with apoptosis caused by the inhibitor or imatinib alone. Similar results were observed when adenoviruses expressing mutant Akt were combined with imatinib, or when LY294002 was combined with cisplatin or etoposide. These studies identify laminin-mediated activation of the PI3K/Akt/mTOR pathway as a mechanism of cellular survival and therapeutic resistance in SCLC cells and suggest that inhibition of the PI3K/Akt/mTOR pathway is one strategy to overcome SCLC resistance mediated by ECM.
Elevated Serum Levels of CC Thymus and Activation-Related Chemokine (TARC) in Primary Hodgkin's Disease: Potential for a Prognostic Factor
Authors: Weihrauch Martin R. , Manzke Oliver , Beyer Marc , Haverkamp Heinz , Diehl Volker , Bohlen Heribert , Wolf Juergen , Schultze Joachim L. 
Published: September 2005

Abstract
The CC thymus and activation-related chemokine (TARC) is a protein, which is highly expressed by Reed-Sternberg cells in Hodgkin's disease and is found in the majority of Hodgkin's disease patients. Within several trials conducted by the German Hodgkin study group, 62 Hodgkin's disease patients were elected based on availability of serum samples post and prior therapy to assess TARC levels by ELISA. TARC levels from 33 patients with continuous complete response (CCR), 20 patients with relapse, and nine patients with progressive disease (PD) were correlated with freedom from treatment failure and survival. As defined in healthy donors (mean value ± 2× SD), a TARC level of &gt;500 pg/mL was considered as elevated. The median TARC levels of all patients at baseline and after completed primary treatment were 5,803 pg/mL (range, 116-73,074 pg/mL) and 663 pg/mL (50-24,709 pg/mL), respectively. TARC levels of patients with PD were higher than those of patients with CCR at baseline and after therapy. Baseline TARC correlated significantly with stage (P = 0.019), erythrocyte sedimentation rate (P = 0.004), leukocyte count (P &lt; 0.001), and lymphocyte count (P = 0.026). A TARC level of &gt;2,000 pg/mL after completed treatment was a significant risk factor for poorer survival (P = 0.02) but not for relapse. In conclusion, monitoring serum TARC levels in Hodgkin's disease patients may add valuable information about therapy success in Hodgkin's disease patients, especially those with PD and should therefore be prospectively evaluated in future trials.
Using a Xenograft Model of Human Breast Cancer Metastasis to Find Genes Associated with Clinically Aggressive Disease
Authors: Kluger Harriet M. , Chelouche Lev Dina , Kluger Yuval , McCarthy Mary M. , Kiriakova Galina , Camp Robert L. , Rimm David L. , Price Janet E. 
Published: September 2005

Abstract
Metastasis is the primary cause of death from breast cancer. A xenograft model was used to identify genes potentially involved with metastasis, comparing expression in the poorly metastatic GI101A human breast cancer cell line and a highly metastatic variant, GILM2. cDNA microarray analyses of these isogenic variants were done using 16K Operon 70-mer oligonucleotide microarray slides. Differentially expressed genes were identified by ANOVA, and differences of ≥2.5-fold were found for 106 genes. Changes in protein or RNA expression were confirmed for 10 of 12 genes. Three markers, heat shock protein 70 (HSP-70), chemokine (C-X-C motif) ligand 1 (CXCL-1), and secreted leukocyte protease inhibitor (SLPI), were studied further with breast cancer tissue microarrays using a novel method of automated quantitative analysis. This uses cytokeratin to define pixels as breast cancer (tumor mask) within the tissue array spot and then measures intensity of marker expression using a cyanine 5–conjugated antibody within the mask. Scores were correlated with clinicopathologic variables. High HSP-70 expression and high nuclear CXCL-1 expression in primary tumors were both associated with decreased survival (P = 0.05 and 0.027, respectively). Expression of each marker was strongly associated with lymph node involvement (P = 0.0002, 0.008, 0.0012, and 0.012 for HSP-70, nuclear CXCL-1, cytoplasmic CXCL-1, and SLPI, respectively). Identification of genes associated with metastasis in experimental models may have clinical implications for the management of breast cancer, because some of these are associated with lymph node metastasis and survival and might be useful as prognostic markers or molecular targets for novel therapies.
The Prostaglandin E2 Receptor EP2 Is Required for Cyclooxygenase 2–Mediated Mammary Hyperplasia
Authors: Chang Sung-Hee , Ai Youxi , Breyer Richard M. , Lane Timothy F. , Hla Timothy 
Published: September 2005

Abstract
Expression of cyclooxygenase 2 (COX-2) in breast cancer correlates with poor prognosis, and COX-2 enzyme inhibitors reduce breast cancer incidence in humans. We recently showed that COX-2 overexpression in the mammary gland of transgenic mice induced mammary cancer. Because prostaglandin E2 (PGE2) is the major eicosanoid and because the EP2 subtype of the PGE2 receptor is highly expressed in the mammary tumors, we tested if this G protein–coupled receptor is required for tumorigenesis. We crossed the MMTV-COX-2 transgenic mice with Ep2−/− mice and studied tumor development in bigenic mice. Lack of EP2 receptor strongly suppressed COX-2–induced effects such as precocious development of the mammary gland in virgins and the development of mammary hyperplasia in multiparous female mice. Interestingly, the expression of amphiregulin, a potent mammary epithelial cell growth factor was down regulated in mammary glands of Ep2−/− mice. Total cyclic AMP (cAMP) levels were reduced in Ep2−/− mammary glands suggesting that PGE2 signaling via the EP2 receptor activates the Gs/cAMP/protein kinase A pathway. In mammary tumor cell lines, expression of the EP2 receptor followed by treatment with CAY10399, an EP2-specific agonist, strongly induced amphiregulin mRNA levels in a protein kinase A–dependent manner. These data suggest that PGE2 signaling via the EP2 receptor in mammary epithelial cells regulate mammary gland hyperplasia by the cAMP-dependent induction of amphiregulin. Inhibition of the EP2 pathway in the mammary gland may be a novel approach in the prevention and/or treatment of mammary cancer.
Tumor Cyclooxygenase-2/Prostaglandin E2–Dependent Promotion of FOXP3 Expression and CD4+CD25+ T Regulatory Cell Activities in Lung Cancer
Authors: Sharma Sherven , Yang Seok-Chul , Zhu Li , Reckamp Karen , Gardner Brian , Baratelli Felicita , Huang Min , Batra Raj K. , Dubinett Steven M. 
Published: September 2005

AbstractCyclooxygenase (COX)-2 and its product prostaglandin (PG) E2 underlie an immunosuppressive network that is important in the pathogenesis of non–small cell lung cancer. CD4+CD25+ T regulatory (Treg) cells play an important role in maintenance of immunologic self-tolerance. CD4+CD25+ Treg cell activities increase in lung cancer and appear to play a role in suppressing antitumor immune responses. Definition of the pathways controlling Treg cell activities will enhance our understanding of limitation of the host antitumor immune responses. Tumor-derived COX-2/PGE2 induced expression of the Treg cell-specific transcription factor, Foxp3, and increased Treg cell activity. Assessment of E-prostanoid (EP) receptor requirements revealed that PGE2-mediated induction of Treg cell Foxp3 gene expression was significantly reduced in the absence of the EP4 receptor and ablated in the absence of the EP2 receptor expression. In vivo, COX-2 inhibition reduced Treg cell frequency and activity, attenuated Foxp3 expression in tumor-infiltrating lymphocytes, and decreased tumor burden. Transfer of Treg cells or administration of PGE2 to mice receiving COX-2 inhibitors reversed these effects. We conclude that inhibition of COX-2/PGE2 suppresses Treg cell activity and enhances antitumor responses.