bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzastaurin, a Protein Kinase Cβ Inhibitor, Suppresses Signaling through the Ribosomal S6 Kinase and Bad Pathways and Induces Apoptosis in Human Gastric Cancer Cells
Authors: Lee Keun-Wook , Kim Sang Gyun , Kim Hwang-Phill , Kwon Euna , You Jiran , Choi Hyung-Jun , Park Jung-Hyun , Kang Byeong-Cheol , Im Seock-Ah , Kim Tae-You , Kim Woo Ho , Bang Yung-Jue 
Published: March 2008

Abstract
Activation of protein kinase C (PKC) has been implicated in gastric carcinogenesis. Enzastaurin is an oral ATP-competitive inhibitor of the PKCβ isozyme. Although enzastaurin was initially advanced to the clinic based on its antiangiogenic activity, it is also known to have a direct effect on a variety of human cancer cells, inducing apoptosis by inhibiting the Akt signal pathway. However, data on enzastaurin for gastric cancer are limited. Therefore, this study was performed to assess the antitumor activity of enzastaurin on gastric cancer cells and to investigate the underlying antitumor mechanisms. Enzastaurin suppressed the proliferation of cultured gastric cancer cells and the growth of gastric carcinoma xenografts. Enzastaurin did not have an effect on gastric cancer cell cycle progression; however, it had a direct apoptosis-inducing effect through the caspase-mediated mitochondrial pathway. Glycogen synthase kinase 3β phosphorylation, a reliable pharmacodynamic marker of enzastaurin activity, and Akt phosphorylation were both decreased after treatment with enzastaurin. Although the p90 ribosomal S6 kinase (Rsk) was also dephosphorylated, Erk phosphorylation was not affected in the enzastaurin-treated gastric cancer cells. Enzastaurin activated Bad, one of the Bcl-2 proapoptotic proteins, through dephosphorylation at Ser112, and depletion of Bad activity resulted in resistance to enzastaurin-induced apoptosis and cytotoxicity in gastric cancer cells. These data suggest that enzastaurin induces apoptosis through Rsk-mediated and Bad-mediated pathways, besides inhibiting the Akt signal cascade. Furthermore, enzastaurin had synergistic or additive effects when combined with 5-fluorouracil, cisplatin, paclitaxel, or irinotecan. These results warrant further clinical investigation of enzastaurin for gastric cancer treatment. [Cancer Res 2008;68(6):1916–26]
Roles of Achaete-Scute Homologue 1 in DKK1 and E-cadherin Repression and Neuroendocrine Differentiation in Lung Cancer
Authors: Osada Hirotaka , Tomida Shuta , Yatabe Yasushi , Tatematsu Yoshio , Takeuchi Toshiyuki , Murakami Hideki , Kondo Yutaka , Sekido Yoshitaka , Takahashi Takashi 
Published: March 2008

AbstractThe proneural basic-helix-loop-helix protein achaete-scute homologue 1 (ASH1) is expressed in a very limited spectrum of normal and cancerous cells in a lineage-specific manner, including normal pulmonary neuroendocrine cells and lung cancer cells with neuroendocrine features. Our previous results indicated that ASH1 may play a crucial role in the growth and survival of lung cancers with neuroendocrine features, which prompted us to investigate the molecular function of ASH1 in relation to its involvement in carcinogenic processes. Herein, we report for the first time that ASH1 functions as a dual transcription factor by activating neuroendocrine differentiation markers and also repressing putative tumor suppressors. This protein was found to inactivate DKK1 and DKK3, negative regulators of Wnt/β-catenin signaling, E-cadherin, and integrin β1 through ASH1-mediated deacetylation and repressive trimethylation of lysine 27 (H3K27me3) of histone H3 in the promoter regions of DKK1 and E-cadherin. In addition, ASH1-transduced A549 adenocarcinoma cells exhibited markedly altered morphology characteristics compared with lung cancer cells with neuroendocrine features both in vitro and in vivo and also grew faster in vivo. Our results provide important clues for a better understanding of the molecular and cellular biological roles of ASH1 in the process of carcinogenesis of lung cancers with neuroendocrine features and warrant future investigations to shed light on the lineage-specific dependency of this transcription factor with dual functions. [Cancer Res 2008;68(6):1647–55]
The Smo/Smo Model: Hedgehog-Induced Medulloblastoma with 90% Incidence and Leptomeningeal Spread
Authors: Hatton Beryl A. , Villavicencio Elisabeth H. , Tsuchiya Karen D. , Pritchard Joel I. , Ditzler Sally , Pullar Barbara , Hansen Stacey , Knoblaugh Sue E. , Lee Donghoon , Eberhart Charles G. , Hallahan Andrew R. , Olson James M. 
Published: March 2008

Abstract
Toward the goal of generating a mouse medulloblastoma model with increased tumor incidence, we developed a homozygous version of our ND2:SmoA1 model. Medulloblastomas form in 94% of homozygous Smo/Smo mice by 2 months of age. Tumor formation is, thus, predictable by age, before the symptomatic appearance of larger lesions. This high incidence and early onset of tumors is ideal for preclinical studies because mice can be enrolled before symptom onset and with a greater latency period before late-stage disease. Smo/Smo tumors also display leptomeningeal dissemination of neoplastic cells to the brain and spine, which occurs in many human cases. Despite an extended proliferation of granule neuron precursors (GNP) in the postnatal external granular layer (EGL), the internal granular layer formed normally in Smo/Smo mice and tumor formation occurred only in localized foci on the superficial surface of the molecular layer. Thus, tumor formation is not simply the result of over proliferation of GNPs within the EGL. Moreover, Smo/Smo medulloblastomas were transplantable and serially passaged in vivo, demonstrating the aggressiveness of tumor cells and their transformation beyond a hyperplastic state. The Smo/Smo model is the first mouse medulloblastoma model to show leptomeningeal spread. The adherence to human pathology, high incidence, and early onset of tumors thus make Smo/Smo mice an efficient model for preclinical studies. [Cancer Res 2008;68(6):1768–76]
Antitumor Activity and Pharmacology of a Selective Focal Adhesion Kinase Inhibitor, PF-562,271
Authors: Roberts Walter Gregory , Ung Ethan , Whalen Pamela , Cooper Beth , Hulford Catherine , Autry Christofer , Richter Daniel , Emerson Earling , Lin Jing , Kath John , Coleman Kevin , Yao Lili , Martinez-Alsina Luis , Lorenzen Marianne , Berliner Martin , Luzzio Michael , Patel Nandini , Schmitt Erika , LaGreca Susan , Jani Jitesh , Wessel Matt , Marr Eric , Griffor Matt , Vajdos Felix 
Published: March 2008

AbstractCancer cells are characterized by the ability to grow in an anchorage-independent manner. The activity of the nonreceptor tyrosine kinase, focal adhesion kinase (FAK), is thought to contribute to this phenotype. FAK localizes in focal adhesion plaques and has a role as a scaffolding and signaling protein for other adhesion molecules. Recent studies show a strong correlation between increased FAK expression and phosphorylation status and the invasive phenotype of aggressive human tumors. PF-562,271 is a potent, ATP-competitive, reversible inhibitor of FAK and Pyk2 catalytic activity with a IC50 of 1.5 and 14 nmol/L, respectively. Additionally, PF-562,271 displayed robust inhibition in an inducible cell-based assay measuring phospho-FAK with an IC50 of 5 nmol/L. PF-562,271 was evaluated against multiple kinases and displays &gt;100× selectivity against a long list of nontarget kinases. PF-562,271 inhibits FAK phosphorylation in vivo in a dose-dependent fashion (calculated EC50 of 93 ng/mL, total) after p.o. administration to tumor-bearing mice. In vivo inhibition of FAK phosphorylation (&gt;50%) was sustained for &gt;4 hours with a single p.o. dose of 33 mg/kg. Antitumor efficacy and regressions were observed in multiple human s.c. xenograft models. No weight loss, morbidity, or mortality were observed in any in vivo experiment. Tumor growth inhibition was dose and drug exposure dependent. Taken together, these data show that kinase inhibition with an ATP-competitive small molecule inhibitor of FAK decreases the phospho-status in vivo, resulting in robust antitumor activity. [Cancer Res 2008;68(6):1935–44]
Oxidative Stress Is Inherent in Prostate Cancer Cells and Is Required for Aggressive Phenotype
Authors: Kumar Binod , Koul Sweaty , Khandrika Lakshmipathi , Meacham Randall B. , Koul Hari K. 
Published: March 2008

Abstract
Reactive oxygen species (ROS) and the coupled oxidative stress have been associated with tumor formation. Several studies suggested that ROS can act as secondary messengers and control various signaling cascades. In the present studies, we characterized the oxidative stress status in three different prostate cancer cells (PC3, DU145, and LNCaP) exhibiting various degree of aggressiveness and normal prostate cells in culture (WPMY1, RWPE1, and primary cultures of normal epithelial cells). We observed increased ROS generation in cancer cells compared with normal cells, and that extramitochondrial source of ROS generator, NAD(P)H oxidase (Nox) systems, are associated with the ROS generation and are critical for the malignant phenotype of prostate cancer cells. Moreover, diphenyliodonium, a specific Nox inhibitor, blocked proliferation, modulated the activity of growth signaling cascades extracellular signal-regulated kinase (ERK)1/ERK2 and p38 mitogen-activated protein kinase as well as AKT protein kinaseB, and caused cyclin B–dependent G2-M cell cycle arrest. We also observed higher degrees of ROS generation in the PC3 cells than DU145 and LNCaP, and that ROS generation is critical for migratory/invasiveness phenotypes. Furthermore, blocking of the ROS production rather than ROS neutralization resulted in decreased matrix metalloproteinase 9 activity as well as loss of mitochondrial potential, plausible reasons for decreased cell invasion and increased cell death. Taken together, these studies show, for the first time, the essential role of ROS production by extramitochondrial source in prostate cancer and suggest that therapies aimed at reducing ROS production might offer effective means of combating prostate cancer in particular, and perhaps other malignancies in general. [Cancer Res 2008;68(6):1777–85]
BAF180 Is a Critical Regulator of p21 Induction and a Tumor Suppressor Mutated in Breast Cancer
Authors: Xia Wei , Nagase Satoru , Montia Amy Gerstein , Kalachikov Sergey M. , Keniry Megan , Su Tao , Memeo Lorenzo , Hibshoosh Hanina , Parsons Ramon 
Published: March 2008

Abstract
Screening for tumor suppressor genes in breast cancer revealed multiple truncating mutations of PB1, which encodes the BAF180 subunit of the PBAF chromatin remodeling complex. Mutation was associated with loss of heterozygosity of the wild-type allele. BAF180 complementation of BAF180-mutant tumor cells caused G1 arrest that was dependent on increased expression of the cyclin/cyclin-dependent kinase inhibitor p21/WAF1/CIP1. Endogenous wild-type BAF180 bound to the p21 promoter and was required for proper p21 expression and G1 arrest after transforming growth factor-β and γ-radiation treatment. BAF180 thus functions on two tumor suppressor signaling pathways as a physiologic mediator of p21 expression. We conclude that BAF180 suppresses tumorigenesis, at least in part, through its ability to regulate p21. [Cancer Res 2008;68(6):1667–74]
Epithelial Progeny of Estrogen-Exposed Breast Progenitor Cells Display a Cancer-like Methylome
Authors: Cheng Alfred S.L. , Culhane Aedín C. , Chan Michael W.Y. , Venkataramu Chinnambally R. , Ehrich Mathias , Nasir Aejaz , Rodriguez Benjamin A.T. , Liu Joseph , Yan Pearlly S. , Quackenbush John , Nephew Kenneth P. , Yeatman Timothy J. , Huang Tim H-M. 
Published: March 2008

AbstractEstrogen imprinting is used to describe a phenomenon in which early developmental exposure to endocrine disruptors increases breast cancer risk later in adult life. We propose that long-lived, self-regenerating stem and progenitor cells are more susceptible to the exposure injury than terminally differentiated epithelial cells in the breast duct. Mammospheres, containing enriched breast progenitors, were used as an exposure system to simulate this imprinting phenomenon in vitro. Using MeDIP-chip, a methylation microarray screening method, we found that 0.5% (120 loci) of human CpG islands were hypermethylated in epithelial cells derived from estrogen-exposed progenitors compared with the non–estrogen-exposed control cells. This epigenetic event may lead to progressive silencing of tumor suppressor genes, including RUNX3, in these epithelial cells, which also occurred in primary breast tumors. Furthermore, normal tissue in close proximity to the tumor site also displayed RUNX3 hypermethylation, suggesting that this aberrant event occurs in early breast carcinogenesis. The high prevalence of estrogen-induced epigenetic changes in primary tumors and the surrounding histologically normal tissues provides the first empirical link between estrogen injury of breast stem/progenitor cells and carcinogenesis. This finding also offers a mechanistic explanation as to why a tumor suppressor gene, such as RUNX3, can be heritably silenced by epigenetic mechanisms in breast cancer. [Cancer Res 2008;68(6):1786–96]
Deletion of Yin Yang 1 Protein in Osteosarcoma Cells on Cell Invasion and CXCR4/Angiogenesis and Metastasis
Authors: de Nigris Filomena , Rossiello Raffaele , Schiano Concetta , Arra Claudio , Williams-Ignarro Sharon , Barbieri Antonio , Lanza Alessandro , Balestrieri Antonio , Giuliano Maria Teresa , Ignarro Louis J. , Napoli Claudio 
Published: March 2008

AbstractWe know that the Yin Yang 1 protein (YY1) overexpression is positively and strongly correlated with the degree of malignancy of bone tumors. Therefore, we questioned whether we could influence cell invasiveness by deleting YY1 in human osteosarcoma cells (SaOs-2), as tested in Matrigel-coated filters and metastasis implantation of such osteosarcoma cells in vivo, by serial analysis with nuclear magnetic resonance. Moreover, we focused our work on the chemokine receptor CXCR4 and its inhibition by T22 antibody, as well as on systemic (direct in vivo assay) and computer-assisted imaging of angiogenesis-related metastasis. Results showed that cell invasiveness and metastasis implantation by wild-type SaOs-2 cells, as evaluated by histology and immunohistochemistry, are associated with up-regulation of CXCR4 expression, which in turn was significantly reduced by T22. In addition, deletion of YY1 (siRNAYY1-SaOs-2) induced a significant decrease of cell invasion and metastasis growth. This phenomenon was associated with decreased vascular endothelial growth factor (VEGF)/angiogenesis and a complex rearrangement of the gene expression profile as evaluated by microarray analysis. In conclusion, YY1 and VEGF/CXCR4 seem to intervene in the pathogenesis of the malignant phenotype of osteosarcoma by acting on cell invasiveness and metastasis growth. [Cancer Res 2008;68(6):1797–808]
Transforming Growth Factor–β Regulates Mammary Carcinoma Cell Survival and Interaction with the Adjacent Microenvironment
Authors: Bierie Brian , Stover Daniel G. , Abel Ty W. , Chytil Anna , Gorska Agnieszka E. , Aakre Mary , Forrester Elizabeth , Yang Li , Wagner Kay-Uwe , Moses Harold L. 
Published: March 2008

Abstract
Transforming growth factor (TGF)–β signaling has been associated with early tumor suppression and late tumor progression; however, many of the mechanisms that mediate these processes are not known. Using Cre/LoxP technology, with the whey acidic protein promoter driving transgenic expression of Cre recombinase (WAP-Cre), we have now ablated the type II TGF-β receptor (TβRII) expression specifically within mouse mammary alveolar progenitors. Transgenic expression of the polyoma virus middle T antigen, under control of the mouse mammary tumor virus enhancer/promoter, was used to produce mammary tumors in the absence or presence of Cre (TβRII(fl/fl);PY and TβRII(fl/fl);PY;WC, respectively). The loss of TGF-β signaling significantly decreased tumor latency and increased the rate of pulmonary metastasis. The loss of TGF-β signaling was significantly correlated with increased tumor size and enhanced carcinoma cell survival. In addition, we observed significant differences in stromal fibrovascular abundance and composition accompanied by increased recruitment of F4/80+ cell populations in TβRII(fl/fl);PY;WC mice when compared with TβRII(fl/fl);PY controls. The recruitment of F4/80+ cells correlated with increased expression of known inflammatory genes including Cxcl1, Cxcl5, and Ptgs2 (cyclooxygenase-2). Notably, we also identified an enriched K5+ dNp63+ cell population in primary TβRII(fl/fl);PY;WC tumors and corresponding pulmonary metastases, suggesting that loss of TGF-β signaling in this subset of carcinoma cells can contribute to metastasis. Together, our current results indicate that loss of TGF-β signaling in mammary alveolar progenitors may affect tumor initiation, progression, and metastasis through regulation of both intrinsic cell signaling and adjacent stromal-epithelial interactions in vivo. [Cancer Res 2008;68(6):1809–19]
Eag1: An Emerging Oncological Target
Authors: Pardo Luis A. , Stühmer Walter 
Published: March 2008

Abstract
Emerging evidence indicates that ion channels act in a variety of physiologic and pathologic processes beyond electronic signal transmission, including in cancer. We recently found that the potassium channel Eag1 can mediate cancer progression and that a monoclonal antibody, which inhibits Eag1 action, can effectively restrict cancer cell proliferation. We discuss how Eag1 targeting may be useful in diagnostic or therapeutic settings. [Cancer Res 2008;68(6):1611–3]
PC3 Human Prostate Carcinoma Cell Holoclones Contain Self-renewing Tumor-Initiating Cells
Authors: Li Hangwen , Chen Xin , Calhoun-Davis Tammy , Claypool Kent , Tang Dean G. 
Published: March 2008

Abstract
Primary keratinocytes exhibit three typical clonal morphologies represented by holoclones, meroclones, and paraclones, with holoclones containing self-renewing stem cells, and meroclones and paraclones containing more mature and differentiated cells. Interestingly, long-term–cultured human epithelial cancer cells in clonal cultures also form holoclones, meroclones, and paraclones, and tumor cell holoclones have been hypothesized to harbor stem-like cells or cancer stem cells. However, the key question of whether tumor cell holoclones genuinely contain tumor-initiating cells has not been directly addressed. Here, using PC3 human prostate carcinoma cells as a model, we provide direct experimental evidence that tumor cell holoclones contain stem-like cells that can initiate serially transplantable tumors. Importantly, holoclones derived from either cultured PC3 cells or holoclone-initiated tumors can be serially passaged and regenerate all three types of clones. In contrast, meroclones and paraclones cannot be continuously propagated and fail to initiate tumor development. Phenotypic characterizations reveal high levels of CD44, α2β1 integrin, and β-catenin expression in holoclones, whereas meroclones and paraclones show markedly reduced expression of these stem cell markers. The present results have important implications in understanding morphologic heterogeneities and tumorigenic hierarchies in human epithelial cancer cells. [Cancer Res 2008;68(6):1820–5]
Gambogic Acid Inhibits Angiogenesis and Prostate Tumor Growth by Suppressing Vascular Endothelial Growth Factor Receptor 2 Signaling
Authors: Yi Tingfang , Yi Zhengfang , Cho Sung-Gook , Luo Jian , Pandey Manoj K. , Aggarwal Bharat B. , Liu Mingyao 
Published: March 2008

Abstract
Gambogic acid (GA), the main active compound of Gamboge hanburyi, has been previously reported to activate apoptosis in many types of cancer cell lines by targeting transferrin receptor and modulating nuclear factor-κB signaling pathway. Whether GA inhibits angiogenesis, which is crucial for cancer and other human diseases, remains unknown. Here, we found that GA significantly inhibited human umbilical vascular endothelial cell (HUVEC) proliferation, migration, invasion, tube formation, and microvessel growth at nanomolar concentration. In a xenograft prostate tumor model, we found that GA effectively inhibited tumor angiogenesis and suppressed tumor growth with low side effects using metronomic chemotherapy with GA. GA was more effective in activating apoptosis and inhibiting proliferation and migration in HUVECs than in human prostate cancer cells (PC3), suggesting GA might be a potential drug candidate in cancer therapy through angioprevention with low chemotoxicity. Furthermore, we showed that GA inhibited the activations of vascular endothelial growth factor receptor 2 and its downstream protein kinases, such as c-Src, focal adhesion kinase, and AKT. Together, these data suggest that GA inhibits angiogenesis and may be a viable drug candidate in antiangiogenesis and anticancer therapies. [Cancer Res 2008;68(6):1843–50]
Bin3 Deletion Causes Cataracts and Increased Susceptibility to Lymphoma during Aging
Authors: Ramalingam Arivudainambi , Duhadaway James B. , Sutanto-Ward Erika , Wang Yan , Dinchuk Joseph , Huang Minzhou , Donover Preston S. , Boulden Janette , McNally Lois M. , Soler Alejandro P. , Muller Alexander J. , Duncan Melinda K. , Prendergast George C. 
Published: March 2008

Abstract
Bin3 encodes an evolutionarily conserved and ubiquitously expressed member of the BAR superfamily of curved membrane and GTPase-binding proteins, which includes the BAR, PCH/F-BAR, and I-BAR adapter proteins implicated in signal transduction and vesicular trafficking. In humans, Bin3 maps to chromosome 8p21.3, a region widely implicated in cancer suppression that is often deleted in non–Hodgkin's lymphomas and various epithelial tumors. Yeast studies have suggested roles for this gene in filamentous actin (F-actin) organization and cell division but its physiologic functions in mammals have not been investigated. Here we report that homozygous inactivation of Bin3 in the mouse causes cataracts and an increased susceptibility to lymphomas during aging. The cataract phenotype was marked by multiple morphologic defects in lens fibers, including the development of vacuoles in cortical fibers and a near total loss of F-actin in lens fiber cells but not epithelial cells. Through 1 year of age, no other phenotypes were apparent; however, by 18 months of age, Bin3−/− mice exhibited a significantly increased incidence of lymphoma. Bin3 loss did not affect normal cell proliferation, F-actin organization, or susceptibility to oncogenic transformation. In contrast, it increased the proliferation and invasive motility of cells transformed by SV40 large T antigen plus activated ras. Our findings establish functions for Bin3 in lens development and cancer suppression during aging. Further, they define Bin3 as a candidate for an unidentified tumor suppressor that exists at the human chromosome 8p21.3 locus. [Cancer Res 2008;68(6):1683–90]