bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inhibition of Fibroblast Growth Factor 19 Reduces Tumor Growth by Modulating β-Catenin Signaling
Authors: Pai Rama , Dunlap Debra , Qing Jing , Mohtashemi Iman , Hotzel Kathy , French Dorothy M. 
Published: July 2008

Abstract
Fibroblast growth factors (FGF) play important roles in development, angiogenesis, and cancer. FGF19 uniquely binds to FGF receptor 4 (FGFR4). Our previous study has shown that FGF19 transgenic tumors have an activated Wnt-pathway phenotype. Wnt signaling is implicated in initiating or promoting FGF signaling in various cell types and organs. In this study, we examined whether FGF19 or inhibition of FGF19 affects the β-catenin signaling pathway using human colon cancer cell lines (HCT116, Colo201). Our results show that FGF19 increases tyrosine phosphorylation of β-catenin and causes loss of β-catenin–E-cadherin binding. FGF19 increases p-GSK3β and active β-catenin levels and anti-FGF19 antibody (1A6) treatment abrogates this effect of FGF19. Anti-FGF19 antibody treatment increases S33/S37/T41 phosphorylation and ubiquitination of β-catenin. Ion-trap mass spectrometric analysis confirmed that 1A6 increases phosphorylation of β-catenin in the NH2 terminus. Using HCT116-paired β-catenin knockout cells, we show that FGF19 induces TCF/LEF reporter activity in parental (WT/Δ45) and in WT/− but not in mutant (−/Δ45) cells, and that inhibition of endogenous FGF19 reduces this reporter activity, indicating that wild-type β-catenin is accessible for modulation. FGFR4 knockdown using inducible short hairpin RNA significantly reduces the colony-forming ability in vitro and tumor growth in vivo. Although cleaved caspase-3 immunoreactivity remains unchanged, the number of ki67-positive nuclei is reduced in FGFR4 knockdown tumor xenograft tissues. Consistent with the reduced β-catenin activation, Taqman analyses show that FGF19/FGFR4 inhibition reduced β-catenin target gene (cyclin D1, CD44, c-jun, Cox-2, UPAR) expression. These findings highlight that FGF19/FGFR4 cross-talk with β-catenin and that pathway intervention reduces tumor growth. [Cancer Res 2008;68(13):5086–95]
The Humoral Immune System Has a Key Prognostic Impact in Node-Negative Breast Cancer
Authors: Schmidt Marcus , Böhm Daniel , von Törne Christian , Steiner Eric , Puhl Alexander , Pilch Henryk , Lehr Hans-Anton , Hengstler Jan G. , Kölbl Heinz , Gehrmann Mathias 
Published: July 2008

Abstract
Estrogen receptor (ER) expression and proliferative activity are established prognostic factors in breast cancer. In a search for additional prognostic motifs, we analyzed the gene expression patterns of 200 tumors of patients who were not treated by systemic therapy after surgery using a discovery approach. After performing hierarchical cluster analysis, we identified coregulated genes related to the biological process of proliferation, steroid hormone receptor expression, as well as B-cell and T-cell infiltration. We calculated metagenes as a surrogate for all genes contained within a particular cluster and visualized the relative expression in relation to time to metastasis with principal component analysis. Distinct patterns led to the hypothesis of a prognostic role of the immune system in tumors with high expression of proliferation-associated genes. In multivariate Cox regression analysis, the proliferation metagene showed a significant association with metastasis-free survival of the whole discovery cohort [hazard ratio (HR), 2.20; 95% confidence interval (95% CI), 1.40–3.46]. The B-cell metagene showed additional independent prognostic information in carcinomas with high proliferative activity (HR, 0.66; 95% CI, 0.46–0.97). A prognostic influence of the B-cell metagene was independently confirmed by multivariate analysis in a first validation cohort enriched for high-grade tumors (n = 286; HR, 0.78; 95% CI, 0.62–0.98) and a second validation cohort enriched for younger patients (n = 302; HR, 0.83; 95% CI, 0.7–0.97). Thus, we could show in three cohorts of untreated, node-negative breast cancer patients that the humoral immune system plays a pivotal role in metastasis-free survival of carcinomas of the breast. [Cancer Res 2008;68(13):5405–13]
GM1 Expression of Non-Hodgkin's Lymphoma Determines Susceptibility to Rituximab Treatment
Authors: Meyer zum Büschenfelde Christian , Feuerstacke Yvonne , Götze Katharina S. , Scholze Katrin , Peschel Christian 
Published: July 2008

Abstract
Immunotherapy with rituximab alone or in conjunction with chemotherapy has significantly improved the treatment outcome of B-cell lymphoma patients. Nevertheless, a subpopulation of patients does not respond to rituximab. The reason for treatment failure as well as the exact mechanism of action is still uncertain. The function of rituximab has long been associated with the partitioning of CD20 molecules to lipid microdomains. We now show that the extent of CD20 recruitment to lipid rafts correlates with response to rituximab. In addition, expression of the raft-associated sphingolipid GM1 on lymphoma cells is associated with the susceptibility of lymphoma cells to rituximab. Furthermore, we show substantially different GM1 expression in various primary non-Hodgkin's lymphomas. Whereas chronic lymphocytic leukemia (CLL) cells have a low GM1 expression, marginal zone lymphoma cells exhibit much higher levels. Differences were not only detected among various lymphoma subgroups but also within one lymphoma subtype. Interestingly, whereas CLL cells from patients with high GM1 expression responded to rituximab, patients with low GM1 expressing CLL cells did not. These data show the importance of membrane microdomains in the effect of rituximab and may offer a predictive factor for the responsiveness of lymphoma cells to rituximab. [Cancer Res 2008;68(13):5414–22]
Rb Depletion Results in Deregulation of E-Cadherin and Induction of Cellular Phenotypic Changes that Are Characteristic of the Epithelial-to-Mesenchymal Transition
Authors: Arima Yoshimi , Inoue Yasumichi , Shibata Tatsuhiro , Hayashi Hidemi , Nagano Osamu , Saya Hideyuki , Taya Yoichi 
Published: July 2008

Abstract
The retinoblastoma tumor suppressor protein (Rb) is mutated or expressed at very low levels in several tumor types, including retinoblastoma and osteosarcoma, as well as small cell lung, colon, prostate, bladder, and breast carcinomas. Loss or reduction of Rb expression is seen most commonly in high-grade breast adenocarcinomas, suggesting that a relationship may exist between loss of Rb function and a less-differentiated state, increased proliferation, and high metastatic potential. In this study, we found that knockdown of Rb by small interfering RNA in MCF7 breast cancer cells disrupts cell-cell adhesion and induces a mesenchymal-like phenotype. The epithelial-to-mesenchymal transition (EMT), a key event in embryonic morphogenesis, is implicated in the metastasis of primary tumors. Additionally, Rb is decreased during growth factor– and cytokine-induced EMT and overexpression of Rb inhibits the EMT in MCF10A human mammary epithelial cells. Ectopic expression and knockdown of Rb resulted in increased or reduced expression of E-cadherin, which is specifically involved in epithelial cell-cell adhesion. Other EMT-related transcriptional factors, including Slug and Zeb-1, are also induced by Rb depletion. Furthermore, we confirmed that Rb binds to an E-cadherin promoter sequence in association with the transcription factor activator protein-2α. Finally, in breast cancer specimens, we observed a concurrent down-regulation of Rb and E-cadherin expression in mesenchymal-like invasive cancers. These findings suggest that Rb inactivation contributes to tumor progression due to not only loss of cell proliferation control but also conversion to an invasive phenotype and that the inhibition of EMT is a novel tumor suppressor function of Rb. [Cancer Res 2008;68(13):5104–12]
Aplidin, a Marine Organism–Derived Compound with Potent Antimyeloma Activity In vitro and In vivo
Authors: Mitsiades Constantine S. , Ocio Enrique M. , Pandiella Atanasio , Maiso Patricia , Gajate Consuelo , Garayoa Mercedes , Vilanova David , Montero Juan Carlos , Mitsiades Nicholas , McMullan Ciaran J. , Munshi Nikhil C. , Hideshima Teru , Chauhan Dharminder , Aviles Pablo , Otero Gabriel , Faircloth Glynn , Mateos M. Victoria , Richardson Paul G. , Mollinedo Faustino , San-Miguel Jesus F. , Anderson Kenneth C. 
Published: July 2008

Abstract
Despite recent progress in its treatment, multiple myeloma (MM) remains incurable, thus necessitating identification of novel anti-MM agents. We report that the marine-derived cyclodepsipeptide Aplidin exhibits, at clinically achievable concentrations, potent in vitro activity against primary MM tumor cells and a broad spectrum of human MM cell lines, including cells resistant to conventional (e.g., dexamethasone, alkylating agents, and anthracyclines) or novel (e.g., thalidomide and bortezomib) anti-MM agents. Aplidin is active against MM cells in the presence of proliferative/antiapoptotic cytokines or bone marrow stromal cells and has additive or synergistic effects with some of the established anti-MM agents. Mechanistically, a short in vitro exposure to Aplidin induces MM cell death, which involves activation of p38 and c-jun NH2-terminal kinase signaling, Fas/CD95 translocation to lipid rafts, and caspase activation. The anti-MM effect of Aplidin is associated with suppression of a constellation of proliferative/antiapoptotic genes (e.g., MYC, MYBL2, BUB1, MCM2, MCM4, MCM5, and survivin) and up-regulation of several potential regulators of apoptosis (including c-JUN, TRAIL, CASP9, and Smac). Aplidin exhibited in vivo anti-MM activity in a mouse xenograft model. The profile of the anti-MM activity of Aplidin in our preclinical models provided the framework for its clinical testing in MM, which has already provided favorable preliminary results. [Cancer Res 2008;68(13):5216–25]
γ-Irradiation–Induced DNA Damage Checkpoint Activation Involves Feedback Regulation between Extracellular Signal-Regulated Kinase 1/2 and BRCA1
Authors: Yan Ying , Black Claudine P. , Cao Phu T. , Haferbier Jamie L. , Kolb Ryan H. , Spieker Rebecca S. , Ristow Alexandra M. , Cowan Kenneth H. 
Published: July 2008

Abstract
Previous studies from our laboratory have shown that the activation of G2-M checkpoint after exposure of MCF-7 breast cancer cells to γ-irradiation (IR) is dependent on the activation of extracellular signal-regulated kinase 1/2 (ERK1/2) signaling. Studies presented in this report indicate that IR exposure of MCF-7 cells is associated with a marked increase in expression of breast cancer 1 (BRCA1) tumor suppressor, an effect that requires ERK1/2 activation and involves posttranscriptional control mechanisms. Furthermore, reciprocal coimmunoprecipitation, as well as colocalization studies, indicate an interaction between BRCA1 and ERK1/2 in both nonirradiated and irradiated cells. Studies using short hairpin RNA targeting BRCA1 show that BRCA1 expression is necessary for IR-induced G2-M cell cycle arrest, as well as ERK1/2 activation in MCF-7 cells. Although BRCA1 expression is not required for IR-induced phosphorylation of ataxia telangiectasia mutated (ATM)–Ser1981, it is required for ATM-mediated downstream signaling events, including IR-induced phosphorylation of Chk2-Thr68 and p53-Ser20. Moreover, BRCA1 expression is also required for IR-induced ATM and rad3 related activation and Chk1 phosphorylation in MCF-7 cells. These results implicate an important interaction between BRCA1 and ERK1/2 in the regulation of cellular response after IR-induced DNA damage in MCF-7 cells. [Cancer Res 2008;68(13):5113–21]
c-Myc and eIF4F Are Components of a Feedforward Loop that Links Transcription and Translation
Authors: Lin Chen-Ju , Cencic Regina , Mills John R. , Robert Francis , Pelletier Jerry 
Published: July 2008

Abstract
The Myc/Max/Mad family of transcription factors and the eukaryotic initiation factor 4F (eIF4F) complex play fundamental roles in regulating cell growth, proliferation, differentiation, and oncogenic transformation. eIF4F is involved in the recruitment of ribosomes to mRNAs and is thought to generally be the rate-limiting phase of translation. Here, we show that c-Myc directly activates transcription of the three subunits of eIF4F (eIF4E, eIF4AI, and eIF4GI). These transcriptional effects are mediated through canonical E-boxes (5′CACGTG3′) present in the promoters of these genes. In addition, the c-Myc antagonist Mad1 down-regulates the expression of eIF4F subunits. We also show that MycER activation stimulates protein synthesis at the level of translation initiation. Increased eIF4F levels result in stimulation of c-Myc mRNA translation specifically, as assessed by quantitative reverse transcription–PCR. We use a murine model of lymphomagenesis to show the expression of eIF4F subunits is also up-regulated by c-Myc in vivo. Our results suggest the presence of a feedforward loop involving c-Myc and eIF4F that serves to link transcription and translation and that could contribute to the effects of c-Myc on cell proliferation and neoplastic growth. [Cancer Res 2008;68(13):5326–34]
In vivo Colocalization of Antigen and CpG within Dendritic Cells Is Associated with the Efficacy of Cancer Immunotherapy
Authors: Nierkens Stefan , den Brok Martijn H. , Sutmuller Roger P.M. , Grauer Oliver M. , Bennink Erik , Morgan Mary E. , Figdor Carl G. , Ruers Theo J.M. , Adema Gosse J. 
Published: July 2008

Abstract
Immunostimulatory cytidyl guanosyl (CpG) motifs are of great interest as cancer vaccine adjuvants. They act as potent inducers of Th1 responses, including the activation of cytotoxic CD8+ T lymphocytes (CTL). Whereas animal models have provided clear evidence that CpG enhances antitumor immunity, clinical trials in humans have thus far been less successful. Applying cryosurgery as an instant in situ tumor destruction technique, we now show that timing of CpG administration crucially affects colocalization of antigen and CpG within EEA-1+ and LAMP-1+ compartments within dendritic cells in vivo. Moreover, antigen/CpG colocalization is directly correlated with antigen cross-presentation, the presence of CTL, and protective antitumor immunity. Thus, failure or success of CpG as a vaccine adjuvant may depend on colocalization of antigen/CpG inside DCs and hence on the timing of CpG administration. These data might aid in the design of future immunotherapeutic strategies for cancer patients. [Cancer Res 2008;68(13):5390–6]
The p53 Homologue ΔNp63α Interacts with the Nuclear Factor-κB Pathway to Modulate Epithelial Cell Growth
Authors: King Kathryn E. , Ponnamperuma Roshini M. , Allen Clint , Lu Hai , Duggal Praveen , Chen Zhong , Van Waes Carter , Weinberg Wendy C. 
Published: July 2008

Abstract
The p53 homologue ΔNp63α is overexpressed and inhibits apoptosis in a subset of human squamous cell carcinomas (SCC). Here, we report that in normal keratinocytes overexpressing ΔNp63α and in human squamous carcinoma cells, ΔNp63α physically associates with phosphorylated, transcriptionally active nuclear c-Rel, a nuclear factor-κB family member, resulting in increased c-Rel nuclear accumulation. This accumulation and the associated enhanced proliferation driven by elevated ΔNp63α are attenuated by c-Rel small interfering RNA or overexpression of mutant IκBαM, indicating that c-Rel–containing complex formation is critical to the ability of elevated ΔNp63α to maintain proliferation in the presence of growth arresting signals. Consistent with a role in growth regulation, ΔNp63α-c-Rel complexes bind a promoter motif and repress the cyclin-dependent kinase inhibitor p21WAF1 in both human squamous carcinoma cells and normal keratinocytes overexpressing ΔNp63α. The relationship between ΔNp63α and activated c-Rel is reflected in their strong nuclear staining in the proliferating compartment of primary head and neck SCC. This is the first report indicating that high levels of ΔNp63α interact with activated c-Rel in keratinocytes and SCC, thereby promoting uncontrolled proliferation, a key alteration in the pathogenesis of cancers. [Cancer Res 2008;68(13):5122–31]
The Cullin 4B–Based UV-Damaged DNA-Binding Protein Ligase Binds to UV-Damaged Chromatin and Ubiquitinates Histone H2A
Authors: Guerrero-Santoro Jennifer , Kapetanaki Maria G. , Hsieh Ching L. , Gorbachinsky Ilya , Levine Arthur S. , Rapić-Otrin Vesna 
Published: July 2008

Abstract
By removing UV-induced lesions from DNA, the nucleotide excision repair (NER) pathway preserves the integrity of the genome. The UV-damaged DNA-binding (UV-DDB) protein complex is involved in the recognition of chromatin-embedded UV-damaged DNA, which is the least understood step of NER. UV-DDB consists of DDB1 and DDB2, and it is a component of the cullin 4A (CUL4A)–based ubiquitin ligase, DDB1-CUL4ADDB2. We previously showed that DDB1-CUL4ADDB2 ubiquitinates histone H2A at the sites of UV lesions in a DDB2-dependent manner. Mutations in DDB2 cause a cancer prone syndrome, xeroderma pigmentosum group E (XP-E). CUL4A and its paralog, cullin 4B (CUL4B), copurify with the UV-DDB complex, but it is unclear whether CUL4B has a role in NER as a separate E3 ubiquitin ligase. Here, we present evidence that CUL4A and CUL4B form two individual E3 ligases, DDB1-CUL4ADDB2 and DDB1-CUL4BDDB2. To investigate CUL4B's possible role in NER, we examined its subcellular localization in unirradiated and irradiated cells. CUL4B colocalizes with DDB2 at UV-damaged DNA sites. Furthermore, CUL4B binds to UV-damaged chromatin as a part of the DDB1-CUL4BDDB2 E3 ligase in the presence of functional DDB2. In contrast to CUL4A, CUL4B is localized in the nucleus and facilitates the transfer of DDB1 into the nucleus independently of DDB2. Importantly, DDB1-CUL4BDDB2 is more efficient than DDB1-CUL4ADDB2 in monoubiquitinating histone H2A in vitro. Overall, this study suggests that DDB1-CUL4BDDB2 E3 ligase may have a distinctive function in modifying the chromatin structure at the site of UV lesions to promote efficient NER. [Cancer Res 2008;68(13):5014–22]
Serotonin Receptors, Novel Targets of Sulforaphane Identified by Proteomic Analysis in Caco-2 Cells
Authors: Mastrangelo Lina , Cassidy Aedin , Mulholland Francis , Wang Wei , Bao Yongping 
Published: July 2008

Abstract
Cancer chemopreventive activity of sulforaphane has been predominantly associated with its ability to induce phase II detoxification enzymes. In the present study, novel targets of sulforaphane were identified and characterized using a proteomics approach. Two-dimensional gel electrophoresis and mass spectrometry were used to produce protein profiles of human colon adenocarcinoma Caco-2 cells treated with 5 μmol/L sulforaphane for 48 h and control cells (0.05% DMSO). Gel comparisons showed the down-regulation to undetectable level of the serotonin receptor 5-HT3 after sulforaphane treatment. In addition, Aldo-keto reductase and d-dopachrome decarboxylase were also differentially expressed in control and treated cell extracts. To elucidate two-dimensional gel findings, the neurotransmitter receptors 5-HT3A, 5-HT1A, 5-HT2C, and the serotonin reuptake transporter were analyzed using Western blotting. Results showed a decrease of neurotransmitter receptors in a dose-dependent manner after sulforaphane treatment. Moreover, after exposure of Caco-2 cells to sulforaphane, nicotinic acetylcholine receptor protein level was increased. These findings suggested a potential effect of sulforaphane on serotonin release. Activation of neurotransmitter receptors followed by initiation of cyclic AMP signaling might be crucial events in colon carcinoma progression. Thus, the effect of sulforaphane may help to elucidate signaling pathways serotonin-mediated in colon cancer and lead to development of potential novel therapeutic agents. [Cancer Res 2008;68(13):5487–91]
Genomic and Proteomic Analysis Reveals a Threshold Level of MYC Required for Tumor Maintenance
Authors: Shachaf Catherine M. , Gentles Andrew J. , Elchuri Sailaja , Sahoo Debashis , Soen Yoav , Sharpe Orr , Perez Omar D. , Chang Maria , Mitchel Dennis , Robinson William H. , Dill David , Nolan Garry P. , Plevritis Sylvia K. , Felsher Dean W. 
Published: July 2008

Abstract
MYC overexpression has been implicated in the pathogenesis of most types of human cancers. MYC is likely to contribute to tumorigenesis by its effects on global gene expression. Previously, we have shown that the loss of MYC overexpression is sufficient to reverse tumorigenesis. Here, we show that there is a precise threshold level of MYC expression required for maintaining the tumor phenotype, whereupon there is a switch from a gene expression program of proliferation to a state of proliferative arrest and apoptosis. Oligonucleotide microarray analysis and quantitative PCR were used to identify changes in expression in 3,921 genes, of which 2,348 were down-regulated and 1,573 were up-regulated. Critical changes in gene expression occurred at or near the MYC threshold, including genes implicated in the regulation of the G1-S and G2-M cell cycle checkpoints and death receptor/apoptosis signaling. Using two-dimensional protein analysis followed by mass spectrometry, phospho-flow fluorescence-activated cell sorting, and antibody arrays, we also identified changes at the protein level that contributed to MYC-dependent tumor regression. Proteins involved in mRNA translation decreased below threshold levels of MYC. Thus, at the MYC threshold, there is a loss of its ability to maintain tumorigenesis, with associated shifts in gene and protein expression that reestablish cell cycle checkpoints, halt protein translation, and promote apoptosis. [Cancer Res 2008;68(13):5132–42]
CAAT/Enhancer Binding Protein Homologous Protein–Dependent Death Receptor 5 Induction Is a Major Component of SHetA2-Induced Apoptosis in Lung Cancer Cells
Authors: Lin Yi-Dan , Chen Shuzhen , Yue Ping , Zou Wei , Benbrook Doris M. , Liu Shengquan , Le Thanh C. , Berlin K. Darrell , Khuri Fadlo R. , Sun Shi-Yong 
Published: July 2008

Abstract
The flexible heteroarotinoids (Flex-Het) represent a novel type of atypical retinoids lacking activity in binding to and transactivating retinoid receptors. Preclinical studies have shown that Flex-Hets induce apoptosis of cancer cells while sparing normal cells and exhibit anticancer activity in vivo with improved therapeutic ratios over conventional retinoid receptor agonists. Flex-Hets have been shown to induce apoptosis through activation of the intrinsic apoptotic pathway. The present study has revealed a novel mechanism underlying Flex-Het–induced apoptosis involving induction of death receptor 5 (DR5). The representative Flex-Het SHetA2 effectively inhibited the growth of human lung cancer cells in cell culture and in mice. SHetA2 induced apoptosis, which could be abrogated by silencing caspase-8 expression, indicating that ShetA2 triggers a caspase-8–dependent apoptosis. Accordingly, SHetA2 up-regulated DR5 expression, including cell surface levels of DR5, and augmented tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)–induced apoptosis. Importantly, small interfering RNA (siRNA)–mediated blockade of DR5 induction conferred cell resistance to SHetA2-induced apoptosis, as well as SHetA2/TRAIL-induced apoptosis. These results show that DR5 induction is a key component of apoptosis induced by SHetA2 or by SHetA2 combined with TRAIL. SHetA2 exerted CAAT/enhancer-binding protein homologous protein (CHOP)–dependent transactivation of the DR5 promoter. Consistently, SHetA2 induced CHOP expression, which paralleled DR5 up-regulation, whereas siRNA-mediated blockage of CHOP induction prevented DR5 up-regulation, indicating CHOP-dependent DR5 up-regulation by SHetA2. Collectively, we conclude that CHOP-dependent DR5 up-regulation is a key event mediating SHetA2-induced apoptosis. [Cancer Res 2008;68(13):5335–44]