bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Apoptosis and Caspase-8 Expression in Neuroblastoma Cells by Isoforms of the IG20 Gene
Authors: Li Liang Cheng , Sheng Jian Rong , Mulherkar Nirupama , Prabhakar Bellur S. , Meriggioli Matthew N. 
Published: September 2008

Abstract
The IG20 gene undergoes alternative splicing resulting in the differential expression of six putative splice variants. Four of these (IG20pa, MADD, IG20-SV2, and DENN-SV) are expressed in virtually all human tissues. However, investigations examining alternative splicing of the IG20 gene to date have been largely limited to nonneural malignant and nonmalignant cells. In this study, we investigated the expression of alternative splice isoforms of the IG20 gene in human neuroblastoma cells. We found that six IG20 splice variants (IG20-SVs) were expressed in two human neuroblastoma cell lines (SK-N-SH and SH-SY5Y), highlighted by the expression of two unique splice isoforms (i.e., KIAA0358 and IG20-SV4). Similarly, we found enriched expression of these two IG20-SVs in human neural tissues derived from cerebral cortex, hippocampus, and, to a lesser extent, spinal cord. Using gain-of-function studies and siRNA technology, we determined that these “neural-enriched isoforms” exerted significant and contrasting effects on vulnerability to apoptosis in neuroblastoma cells. Specifically, expression of KIAA0358 exerted a potent antiapoptotic effect in both the SK-N-SH and SH-SY5Y neuroblastoma cell lines, whereas expression of IG20-SV4 had proapoptotic effects directly related to the activation of caspase-8 in these cells, which have minimal or absent constitutive caspase-8 expression. These data indicate that the pattern of expression of these neural-enriched IG20-SVs regulates the expression and activation of caspase-8 in certain neuroblastoma cells, and that manipulation of IG20-SV expression pattern may represent a potent therapeutic strategy in the therapy of neuroblastoma and perhaps other cancers. [Cancer Res 2008;68(18):7352–61]
Purine-Rich Box-1–Mediated Reduced Expression of CD20 Alters Rituximab-Induced Lysis of Chronic Lymphocytic Leukemia B Cells
Authors: Mankaï Amani , Bordron Anne , Renaudineau Yves , Martins-Carvalho Christine , Takahashi Shinichiro , Ghedira Ibtissem , Berthou Christian , Youinou Pierre 
Published: September 2008

AbstractThe anti-CD20 monoclonal antibody rituximab has been less successful in treating chronic lymphocytic leukemia (CLL) than lymphoma, possibly due to the lower density of CD20 on B lymphocytes from CLL patients than on those from lymphoma patients. This lowering may result from insufficiency of one of the transcription factors of cd20. Of these, purine-rich box-1 (PU.1) is poorly expressed in CLL. To estimate its weight in CD20 expression, pu.1 cDNA was transfected into CLL B cells and shown to raise the membrane expression of CD20 and to improve the rituximab-induced lysis of transfected cells. Granulocyte macrophage colony-stimulating factor and all-trans-retinoic acids were not involved in the defective expression of PU.1 or the excessive methylation of the pu.1 gene, because 6 of 14 CLL samples tested were normally methylated. This was confirmed by the failure of DNA methyltransferase inhibitors to restore pu.1 transcription in hypermethylated CLL, and, in fact, the expression of PU.1 was down-regulated by excessive expression of the FMS proto-oncogene–like tyrosine kinase 3 (Flt3) receptor. This abnormality is consistent with our finding of elevated levels of Flt3 ligand (FL) in 20 of 23 CLL sera tested. We propose that FL-dependent increased Flt3 signaling prevents the expression of PU.1, which down-regulates that of CD20, and accounts for resistance of leukemic B cells to rituximab-induced lysis. [Cancer Res 2008;68(18):7512–9]
A Novel Gene Expression Profile in Lymphatics Associated with Tumor Growth and Nodal Metastasis
Authors: Clasper Steven , Royston Daniel , Baban Dilair , Cao Yihai , Ewers Stephan , Butz Stefan , Vestweber Dietmar , Jackson David G. 
Published: September 2008

AbstractInvasion of lymphatic vessels is a key step in the metastasis of primary tumors to draining lymph nodes. Although the process is enhanced by tumor lymphangiogenesis, it is unclear whether this is a consequence of increased lymphatic vessel number, altered lymphatic vessel properties, or both. Here we have addressed the question by comparing the RNA profiles of primary lymphatic endothelial cells (LEC) isolated from the vasculature of normal tissue and from highly metastatic T-241/vascular endothelial growth factor (VEGF)-C fibrosarcomas implanted in C57BL/6 mice. Our findings reveal significant differences in expression of some 792 genes (i.e., ≥2-fold up- or down-regulated, P ≤ 0.05) that code for a variety of proteins including components of endothelial junctions, subendothelial matrix, and vessel growth/patterning. The tumor LEC profile, validated by immunohistochemical staining, is distinct from that of normal, inflammatory cytokine, or mitogen-activated LEC, characterized by elevated expression of such functionally significant molecules as the tight junction regulatory protein endothelial specific adhesion molecule (ESAM), the transforming growth factor-β coreceptor Endoglin (CD105), the angiogenesis-associated leptin receptor, and the immunoinhibitory receptor CD200, and reduced expression of subendothelial matrix proteins including collagens, fibrillin, and biglycan. Moreover, we show similar induction of ESAM, Endoglin, and leptin receptor within tumor lymphatics in a series of human head and neck and colorectal carcinomas, and uncover a dramatic correlation between ESAM expression and nodal metastasis that identifies this marker as a possible prognostic indicator. These findings reveal a remarkable degree of phenotypic plasticity in cancer lymphatics and provide new insight into the processes of lymphatic invasion and lymph node metastasis. [Cancer Res 2008;68(18):7293–303]
Curcumin Inhibits Lung Cancer Cell Invasion and Metastasis through the Tumor Suppressor HLJ1
Authors: Chen Huei-Wen , Lee Jen-Yi , Huang Ji-Ying , Wang Chi-Chung , Chen Wan-Jiun , Su Sheng-Fang , Huang Chia-Wen , Ho Chao-Chi , Chen Jeremy J.W. , Tsai Meng-Feng , Yu Sung-Liang , Yang Pan-Chyr 
Published: September 2008

Abstract
Curcumin (diferuloylmethane) is an active component of the spice turmeric and has a diversity of antitumor activities. In this study, we found that curcumin can inhibit cancer cell invasion and metastasis through activation of the tumor suppressor DnaJ-like heat shock protein 40 (HLJ1). Human lung adenocarcinoma cells (CL1-5) treated with curcumin (1–20 μmol/L) showed a concentration-dependent reduction in cell migration, invasion, and metastatic ability, and this was associated with increased HLJ1 expression. Knockdown of HLJ1 expression by siRNA was able to reverse the curcumin-induced anti-invasive and antimetastasis effects in vitro and in vivo. The HLJ1 promoter and enhancer in a luciferase reporter assay revealed that curcumin transcriptionally up-regulates HLJ1 expression through an activator protein (AP-1) site within the HLJ1 enhancer. JunD, one of the AP-1 components, was significantly up-regulated by curcumin (1–20 μmol/L) in a concentration- and time-dependent manner. Knockdown of JunD expression could partially reduce the curcumin-induced HLJ1 activation and diminish the anti-invasive effect of curcumin, indicating that JunD would seem to be involved in curcumin-induced HLJ1 expression. Curcumin was able to induce c-Jun NH2-kinase (JNK) phosphorylation, whereas the JNK inhibitor (SP-600125) could attenuate curcumin-induced JunD and HLJ1 expression. Activation of HLJ1 by curcumin further leads to up-regulation of E-cadherin and a suppression of cancer cell invasion. Our results show that curcumin induces HLJ1, through activation of the JNK/JunD pathway, and inhibits lung cancer cell invasion and metastasis by modulating E-cadherin expression. This is a novel mechanism and supports the application of curcumin in anti–cancer metastasis therapy. [Cancer Res 2008;68(18):7428–38]
Cyp1b1 Exerts Opposing Effects on Intestinal Tumorigenesis via Exogenous and Endogenous Substrates
Authors: Halberg Richard B. , Larsen Michele Campaigne , Elmergreen Tammy L. , Ko Alex Y. , Irving Amy A. , Clipson Linda , Jefcoate Colin R. 
Published: September 2008

Abstract
Cytochrome P450 1B1 (Cyp1b1) metabolism contributes to physiologic functions during embryogenesis but also to carcinogenic activation of polycyclic aromatic hydrocarbons (PAH). We generated Cyp1b1-deficient mice carrying the Min allele of the adenomatous polyposis coli gene. These Cyp1b1-deficient Min mice developed twice as many tumors as Min controls, which, however, remained similar in size and histology. Tumors from older (130 days) Cyp1b1-deficient Min mice selectively exhibited focal areas of nuclear atypia associated with less organized epithelia. The metabolism of endogenous substrates by Cyp1b1, therefore, suppresses tumor initiation but also affects progression. Treatment of Min mice with 7,12-dimethylbenzanthracene (DMBA) doubled both tumor multiplicity and size within 20 days but not when mice lacked Cyp1b1. This was paralleled by an abnormal staining of crypts with β-catenin, phospho-IκB kinase, and RelA, which may represent an early stage of tumorigenesis similar to aberrant crypt formation. Cyp1b1 deletion did not affect circulating DMBA and metabolites. Cyp1b1 expression was higher in the tumors compared with normal small intestines. Increased tumorigenesis may, therefore, arise from generation of DMBA metabolites by Cyp1b1 in the developing tumors. Benzo(a)pyrene (BP), which is similarly activated by Cyp1b1 in vitro, did not affect tumorigenesis in Min mice. By contrast, BP and DMBA each suppressed tumor multiplicity in the absence of Cyp1b1. Cyp1b1 metabolism of DMBA and endogenous oxygenation products may each affect a tumor-promoting nuclear factor-κB activation, whereas Ah receptor activation by PAH affects suppression. Tumorigenesis may, therefore, depend on activation of PAH by Cyp1b1 and on offsetting suppression by Cyp1b1 of endogenous tumor-enhancing substrates. [Cancer Res 2008;68(18):7394–402]
HSF1 as a Mitotic Regulator: Phosphorylation of HSF1 by Plk1 Is Essential for Mitotic Progression
Authors: Lee Yoon-Jin , Kim Eun-Ho , Lee Jae Seon , Jeoung Dooil , Bae Sangwoo , Kwon Seung Hae , Lee Yun-Sil 
Published: September 2008

Abstract
Previously, heat shock factor 1 (HSF1) had been reported to induce genomic instability and aneuploidy by interaction with Cdc20. Here, we have further examined the functions of HSF1 in the regulation of mitosis. A null mutant or knockdown of HSF1 caused defective mitotic progression. By monitoring chromosomes in living cells, we determined that HSF1 was localized to the centrosome in mitosis and especially to the spindle poles in metaphase. HSF1 was phosphorylated by Plk1 at Ser216 of the DSGXXS motif during the timing of mitosis and a phospho-defective mutant form of HSF1 inhibited mitotic progression. Phosphorylated HSF1 during spindle pole localization underwent ubiquitin degradation through the SCFβ-TrCP pathway. However, binding of HSF1 with Cdc20 stabilized the phosphorylation of HSF1. Moreover, SCFβ-TrCP–mediated degradation only occurred when phosphorylated HSF1 was released from Cdc20. HSF1 phosphorylation at Ser216 occurred in the early mitotic period with simultaneous binding of Cdc20. The interaction of HSF1 with SCFβ-TrCP was followed and then the interaction of APC/Cdc20 was subsequently observed. From these findings, it was shown that Plk1 phosphorylates HSF1 in early mitosis and that the binding of phosphorylated HSF1 with Cdc20 and ubiquitin degradation by SCFβ-TrCP regulates mitotic progression. [Cancer Res 2008;68(18):7550–60]
Growth Inhibition and Radiosensitization of Glioblastoma and Lung Cancer Cells by Small Interfering RNA Silencing of Tumor Necrosis Factor Receptor–Associated Factor 2
Authors: Zheng Min , Morgan-Lappe Susan E. , Yang Jie , Bockbrader Katrina M. , Pamarthy Deepika , Thomas Dafydd , Fesik Stephen W. , Sun Yi 
Published: September 2008

AbstractRadiotherapy combined with chemotherapy is the treatment of choice for glioblastoma and locally advanced lung cancer, but radioresistance of these two types of cancer remains a significant therapeutic hindrance. To identify molecular target(s) for radiosensitization, we screened a small interfering RNA (siRNA) library targeting all protein kinases and E3 ubiquitin ligases in the human genome and identified tumor necrosis factor receptor–associated factor 2 (TRAF2). Silencing of TRAF2 using siRNA caused a significant growth suppression of glioblastoma U251 cells and moderately sensitized these radioresistant cells to radiation. Overexpression of a really interesting new gene (RING)–deleted dominant-negative TRAF2 mutant also conferred radiosensitivity, whereas overexpression of wild-type (WT) TRAF2 significantly protected cells from radiation-induced killing. Likewise, siRNA silencing of TRAF2 in radioresistant lung cancer H1299 cells caused growth suppression and radiosensitization, whereas overexpression of WT TRAF2 enhanced radioresistance in a RING ligase-dependent manner. Moreover, siRNA silencing of TRAF2 in UM-SCC-1 head and neck cancer cells also conferred radiosensitization. Further support for the role of TRAF2 in cancer comes from the observations that TRAF2 is overexpressed in both lung adenocarcinoma tissues and multiple lung cancer cell lines. Importantly, TRAF2 expression was very low in normal bronchial epithelial NL20 cells, and TRAF2 silencing had a minimal effect on NL20 growth and radiation sensitivity. Mechanistically, TRAF2 silencing blocks the activation of the nuclear factor-κB signaling pathway and down-regulates several G2-M cell cycle control proteins, resulting in enhanced G2-M arrest, growth suppression, and radiosensitization. Our studies suggest that TRAF2 is an attractive drug target for anticancer therapy and radiosensitization. [Cancer Res 2008;68(18):7570–8]
Transient Inhibition of ATM Kinase Is Sufficient to Enhance Cellular Sensitivity to Ionizing Radiation
Authors: Rainey Michael D. , Charlton Maura E. , Stanton Robert V. , Kastan Michael B. 
Published: September 2008

Abstract
In response to DNA damage, the ATM protein kinase activates signal transduction pathways essential for coordinating cell cycle progression with DNA repair. In the human disease ataxia-telangiectasia, mutation of the ATM gene results in multiple cellular defects, including enhanced sensitivity to ionizing radiation (IR). This phenotype highlights ATM as a potential target for novel inhibitors that could be used to enhance tumor cell sensitivity to radiotherapy. A targeted compound library was screened for potential inhibitors of the ATM kinase, and CP466722 was identified. The compound is nontoxic and does not inhibit phosphatidylinositol 3-kinase (PI3K) or PI3K-like protein kinase family members in cells. CP466722 inhibited cellular ATM-dependent phosphorylation events and disruption of ATM function resulted in characteristic cell cycle checkpoint defects. Inhibition of cellular ATM kinase activity was rapidly and completely reversed by removing CP466722. Interestingly, clonogenic survival assays showed that transient inhibition of ATM is sufficient to sensitize cells to IR and suggests that therapeutic radiosensitization may only require ATM inhibition for short periods of time. The ability of CP466722 to rapidly and reversibly regulate ATM activity provides a new tool to ask questions about ATM function that could not easily be addressed using genetic models or RNA interference technologies. [Cancer Res 2008;68(18):7466–74]
Tube Travel: The Role of Proteases in Individual and Collective Cancer Cell Invasion
Authors: Friedl Peter , Wolf Katarina 
Published: September 2008

Abstract
Recent advances in high-resolution multimodal microscopy reveal how MT1-matrix metalloproteinase (MMP)/MMP-14 and other cell surface proteases degrade and remodel the extracellular matrix (ECM) to drive the dissemination of cancer cells into normal adjacent tissue. By cleaving collagen fibers and repatterning them into parallel bundles, individual cells reorient the ECM to permit movement in tube-like microtracks. Cells along the edge of these tubes can excavate ECM outward, generating macrotracks through which collective mass movement of cancer cells can occur. These findings develop our understanding of invasive processes in cancer and how to attack them by interfering with MMP-14 activity. [Cancer Res 2008;68(18):7247–9]
One-Hit Effects in Cancer: Altered Proteome of Morphologically Normal Colon Crypts in Familial Adenomatous Polyposis
Authors: Yeung Anthony T. , Patel Bhavinkumar B. , Li Xin-Ming , Seeholzer Steven H. , Coudry Renata A. , Cooper Harry S. , Bellacosa Alfonso , Boman Bruce M. , Zhang Tao , Litwin Samuel , Ross Eric A. , Conrad Peggy , Crowell James A. , Kopelovich Levy , Knudson Alfred 
Published: September 2008

Abstract
We studied patients with Familial Adenomatous Polyposis (FAP) because they are virtually certain to develop colon cancer, and because much is known about the causative APC gene. We hypothesized that the inherited heterozygous mutation itself leads to changes in the proteome of morphologically normal crypts and the proteins that changed may represent targets for preventive and therapeutic agents. We determined the differential protein expression of morphologically normal colon crypts of FAP patients versus those of individuals without the mutation, using two-dimensional gel electrophoresis, mass spectrometry, and validation by two-dimensional gel Western blotting. Approximately 13% of 1,695 identified proteins were abnormally expressed in the morphologically normal crypts of APC mutation carriers, indicating that a colon crypt cell under the one-hit state is already abnormal. Many of the expression changes affect pathways consistent with the function of the APC protein, including apoptosis, cell adhesion, cell motility, cytoskeletal organization and biogenesis, mitosis, transcription, and oxidative stress response. Thus, heterozygosity for a mutant APC tumor suppressor gene alters the proteome of normal-appearing crypt cells in a gene-specific manner, consistent with a detectable one-hit event. These changes may represent the earliest biomarkers of colorectal cancer development, potentially leading to the identification of molecular targets for cancer prevention. [Cancer Res 2008;68(18):7579–86]
Development of a Small-Molecule Serum- and Glucocorticoid-Regulated Kinase-1 Antagonist and Its Evaluation as a Prostate Cancer Therapeutic
Authors: Sherk Andrea B. , Frigo Daniel E. , Schnackenberg Christine G. , Bray Jeffrey D. , Laping Nicholas J. , Trizna Walter , Hammond Marlys , Patterson Jaclyn R. , Thompson Scott K. , Kazmin Dmitri , Norris John D. , McDonnell Donald P. 
Published: September 2008

Abstract
Androgens, through their actions on the androgen receptor (AR), are required for the development of the prostate and contribute to the pathologic growth dysregulation observed in prostate cancers. Consequently, androgen ablation has become an essential component of the pharmacotherapy of prostate cancer. In this study, we explored the utility of targeting processes downstream of AR as an alternate approach for therapy. Specifically, we show that the serum and glucocorticoid-regulated kinase 1 (SGK1) gene is an androgen-regulated target gene in cellular models of prostate cancer. Furthermore, functional serum- and glucocorticoid-regulated kinase 1 (SGK1) protein, as determined by the phosphorylation of its target Nedd4-2, was also increased with androgen treatment. Importantly, we determined that RNA interference–mediated knockdown of SGK1 expression attenuates the androgen-mediated growth of the prostate cancer cell line LNCaP. Given these findings, we explored the utility of SGK1 as a therapeutic target in prostate cancer by developing and evaluating a small-molecule inhibitor of this enzyme. From these studies emerged GSK650394, a competitive inhibitor that quantitatively blocks the effect of androgens on LNCaP cell growth. Thus, in addition to androgen ablation, inhibition of pathways downstream of AR is likely to have therapeutic utility in prostate cancer. [Cancer Res 2008;68(18):7475–83]
The Peptidyl-Isomerase Pin1 Regulates p27kip1 Expression through Inhibition of Forkhead Box O Tumor Suppressors
Authors: Brenkman Arjan B. , de Keizer Peter L.J. , van den Broek Niels J.F. , van der Groep Petra , van Diest Paul J. , van der Horst Armando , Smits Alida M.M. , Burgering Boudewijn M.T. 
Published: September 2008

Abstract
The Forkhead box O (FOXO) protein family is an evolutionarily conserved subclass of transcription factors recently identified as bona fide tumor suppressors. Preventing the accumulation of cellular damage due to oxidative stress is thought to underlie its tumor-suppressive role. Oxidative stress, in turn, also feedback controls FOXO4 function. Regulation of this process, however, is poorly understood but may be relevant to the ability of FOXO to control tumor suppression. Here, we characterize novel FOXO4 phosphorylation sites after increased cellular oxidative stress and identify the isomerase Pin1, a protein frequently found to be overexpressed in cancer, as a critical regulator of p27kip1 through FOXO4 inhibition. We show that Pin1 requires these phosphorylation events to act negatively on FOXO4 transcriptional activity. Consistent with this, oxidative stress induces binding of Pin1 to FOXO, thereby attenuating its monoubiquitination, a yet uncharacterized mode of substrate modulation by Pin1. We have previously shown that monoubiquitination is involved in controlling nuclear translocation in response to cellular stress, and indeed, Pin1 prevents nuclear FOXO4 accumulation. Interestingly, Pin1 acts on FOXO through stimulation of the activity of the deubiquitinating enzyme HAUSP/USP7. Ultimately, this results in decreased transcriptional activity towards target genes, including the cell cycle arrest gene p27kip1. Notably, in a primary human breast cancer panel, low p27kip1 levels inversely correlated with Pin1 expression. Thus, Pin1 is identified as a novel negative FOXO regulator, interconnecting FOXO phosphorylation and monoubiquitination in response to cellular stress to regulate p27kip1. [Cancer Res 2008;68(18):7597–605]
An Immortalization-Dependent Switch in Integrin Function Up-regulates MMP-9 to Enhance Tumor Cell Invasion
Authors: Lamar John M. , Pumiglia Kevin M. , DiPersio C. Michael 
Published: September 2008

Abstract
Integrins, the major receptors for cell adhesion to the extracellular matrix, play important roles during tumor progression. However, it is still unclear whether genetic lesions that occur during carcinoma development can lead to altered integrin function, and how changes in integrin function contribute to subsequent carcinoma progression. Loss-of-function mutations in p53 and activating mutations in H-Ras, which immortalize and transform epithelial cells, respectively, are common causal events in squamous cell carcinoma (SCC). Phenotypes resulting from these two genetic lesions promote SCC progression and are, therefore, potential targets for anticancer therapies. We developed a model system of keratinocyte transformation that has allowed us to investigate the individual roles of p53 mutation and oncogenic Ras mutation in the acquisition of integrin α3β1-regulated phenotypes that promote SCC progression. Using this model, we show that keratinocyte immortalization by p53-null mutation causes a switch in α3β1 function that induces matrix metalloproteinase (MMP)-9 gene expression in tumorigenic cells. This acquired α3β1-dependent regulation of MMP-9 was maintained during subsequent transformation by oncogenic Ras, and it promoted invasion of tumorigenic keratinocytes. Our results show that loss of p53 function leads to changes in integrin-mediated gene regulation that occur during SCC progression and play a critical role in tumor cell invasion. [Cancer Res 2008;68(18):7371–9]