bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 3064: HPP1 tumor suppression and JAK-STAT signaling
Authors: Elahi Abul , Hernandez Jonathan M. , Shibata David 
Published: February 2011

Abstract
Introduction:
HPP1 is a putative tumor suppressor gene that is epigenetically silenced in various tumor types including colorectal cancer. We have previously reported that the ectopic expression of HPP1 results in the upregulation of STAT1, STAT2 and a number of interferon-inducible genes, and that activation of STAT1 is critical for HPP1's growth suppressive functions. We have sought to comprehensively evaluate alterations and the importance of the JAK-STAT signaling axis as they relate to HPP1 overexpression.
Methods:
Full-length HPP1 was amplified and cloned into the pcDNA3.1 expression vector which was then stably transfected into the HCT116 colon cancer cell line. Western Blot analyses were performed to assess both expression and activation for STAT1, STAT2, STAT3, JAK1, JAK2, JAK3 and TYK2 in HPP1 transfectants and empty vector controls. Functional STAT1 and STAT2 promoter binding were quantified using luciferase reporter plasmids containing ISRE-(Interferon Stimulated Regulatory Element) and GAS-(Gamma Activated Site) promoter elements.
Results:
The overexpression of HPP1 resulted in increased expression and activation of STAT1 and STAT2. Overexpression of HPP1 was associated with significant increases in both STAT1:STAT1 (p=0.007) and STAT1:STAT2 (p=0.036) binding, suggesting HPP1 mediates tumor suppression via association with Type II-like (gamma) and Type I-like (alpha) interferon pathways. Furthermore, additional corresponding dose-dependent inductions of STAT1 and STAT2 activation were achieved by treatment of HPP1 transfectants with interferon gamma and alpha. In contrast to STAT1 and 2, forced expression of HPP1 resulted in a downregulation of both STAT3 total expression and activation. HPP1 transfectants demonstrated increases in expression and activation of JAK1, JAK2 and JAK3, as well as a reduction in levels of TYK2 and phosphoTYK2.
Conclusion:
Activation of JAK1, 2 and 3 likely contribute to the upregulation and phosphorylation of STAT1 and STAT2 which in turn, result in the activation of Type I- and Type II-like interferon-inducible elements and their growth suppressive effects. Moreover, we demonstrate a reciprocal abrogation of the oncogenic STAT3 and its associated dominant kinase TYK2. HPP1 appears to mediate tumor suppression via modulation of JAK-STAT-interferon pathways.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3064.
Abstract 3079: Loss of β2-spectrin may lead to the activation of telomerase reverse transcriptase (TERT) and hepatocellular cancer formation
Authors: Jiao Zhongxian , Shukla Sanjeev , Kumar Gyanendra , Yao Wenguo , Cao Hong , Jogunoori Wilma SR , Yao Zhixing , Mishra Lopa , Mishra Bibhuti 
Published: February 2011

Abstract
Background and Aims: Telomerase is a specialized reverse transcriptase (TERT) that synthesizes repeat DNA sequences at telomeres- the specialized ends of chromosomes is suppressed in normal cells by multiple proteins that include TGF-β and Smad3 resulting in the progressive shortening of telomeres with each cell division, ultimately leading to chromosomal instability and cellular replicative senescence or growth arrest. Emerging evidence indicates that β2-spectrin (β2SP), a Smad3/Smad4 adaptor protein required for TGF-β signaling, is a powerful tumor suppressor. β2SP+/−, β2SP+/−/Smad3+/− and β2SP+/−/Smad4+/− mice dramatically develop Hepatic cancers. Because TERT is markedly activated in β2SP+/−/Smad3+/− hepatocellular cancer tissues compared to Smad3−/− tissues, we hypothesized that β2SP interaction could be involved in the interaction with Smad3 to suppress TERT expression in normal tissues, and the loss of β2SP may lead to telomerase gene activation resulting in HCC. Results: We tested human TERT (hTERT) expression levels in several HCC cell lines that have different levels of β2SP. hTERT expression levels negatively correlate with β2SP by Western Blot analysis. Loss of β2SP in β2SP+/− and β2SP−/− mouse embryonic fibroblasts (MEFs) significantly activated mTERT expression. Co-transfection of a β2SP expression plasmid and hTERT promoter-luciferase construct significantly inhibited the hTERT promoter in β2SP-deficient SNU-398 cells. Depletion of Smad3 by in vitro RNAi and the expression of hTERT-luciferase in Smad3 depleted cells upon co-transfection with Smad3 and/or β2SP expression plasmids suggest that both Smad3 and β2SP are required for the suppression of hTERT. Furthermore, chromatin immunoprecipitation (ChIP) assay suggests binding of Smad3/β2SP protein to hTERT promoter. Conclusions: Taken together our data suggest that divergent pathways converge on β2SP and Smad3 for the regulation of TERT. Activation of the TGF-β signaling pathway with suppression of TERT provides a strong strategy for generating targeted therapeutics to these lethal human cancers.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3079.
Abstract 3080: Functional studies of a cell cycle and angiogenesis-related candidate tumor suppressor gene, Mirror image polydactyly 1, in nasopharyngeal carcinoma
Authors: Cheung Arthur Kwok Leung , Lung Hong Lok , Ko Josephine Mun Yee , Lung Maria Li 
Published: February 2011

Abstract
Background and aims: Nasopharyngeal carcinoma (NPC) is a cancer with an especially high incidence in Southern China. We performed functional complementation studies to confirm and map critical regions on chromosome 14 associated with its tumor-suppressive ability. An interesting candidate tumor suppressor gene (TSG), Mirror image polydactyly 1 (MIPOL1) was identified. Previously this gene has only been reported to be associated with a genetic developmental disorder. Its contribution to cancer and its functional role in NPC was, therefore, investigated. Methods: A tetracycline-inducible system was used to obtain MIPOL1-expressing clones. A wild-type MIPOL1 gene was transferred into a NPC cell line, HONE1-2. Functional studies such as in vivo nude mouse tumorigenicity, HUVEC tube formation, and cell cycle analysis assays were used to investigate the function of MIPOL1. Results: MIPOL1 re-expression can suppress tumor growth in vivo and induce cell cycle arrest through increasing p21(WAF1/CIP1) and p27(KIP1) expression. Furthermore, expression of MIPOL1 can inhibit angiogenesis in the tube formation assay. Functional pathways were studied by detection of change in expression levels of different angiogenesis-related proteins in cell lysates and conditional medium of those stable clones. Conclusions: An interesting candidate TSG, MIPOL1, was identified. Functional studies confirm that MIPOL1 can suppress tumor growth in vivo. It can induce cell cycle arrest through the p21(WAF1/CIP1) and p27(KIP1) pathways. MIPOL1 can also inhibit angiogenesis, and this further confirms its importance in tumor suppression. Changes in expression of different angiogenesis-related proteins were observed. MIPOL1 is a good candidate tumor suppressor gene in NPC and warrants further study.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3080.
Abstract 3089: Heterogenous high level HER-2 amplification in a small subset of colorectal cancers
Authors: Marx Andreas Holger , Simon Ronald , Sauter Guido 
Published: February 2011

Abstract
HER-2 is the molecular target for antibody-based treatment of breast cancer (trastuzumab). The potential benefit of anti-HER-2 therapy is currently investigated in several other HER-2 amplified cancers. For example, trastuzumab was recently shown to be effective in HER-2 positive gastric cancer. To address the potential applicability of anti-HER-2 therapy in CRC, tissue microarray (TMA) sections and colorectal resection specimens of 1851 CRC were analyzed for HER-2 overexpression and amplification using FDA approved reagents for immunohistochemistry and fluorescence in situ hybridization. HER-2 amplification was seen in 2.5% and HER-2 overexpression in 2.7 % of 1439 interpretable CRC. Amplification was often high level with HER-2 copies ranging from 4 to 60 per tumor cell and was strongly related to protein overexpression. HER-2 amplification and overexpression were unrelated to histological tumor type, tumor localization, grading, pT, pN, pM or survival. As heterogeneity of drug target expression could represent a major drawback for targeted cancer therapy we next studied HER-2 heterogeneity in selected cases. Extensive evaluation of all available large sections from patients with HER-2 positive CRC revealed heterogenous findings in 3 of 4 cases.
In summary, high level HER-2 amplification occurs in a small fraction of CRCs. Heterogeneity of amplification may limit the utility of anti HER-2 therapy in some of these tumors and therefore, adequate clinical trials are needed to further evaluate this approach.
Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3089.
Abstract 3125: EGFRvIII translocates to the nucleus and regulates gene transcription with STAT5
Authors: Latha Khatri , Chumbalkar Vaibhav , Li Ming , Hwang YeoHyeon , Gururaj Anupama , Maywald Rebecca , Dakeng Sumana , Dao Lixia , Baggerly Keith , Sawaya Raymond , Cavenee Webster , Furnaru Frank , Bögler Oliver 
Published: February 2011

Abstract
Dysregulation of receptor tyrosine kinases is a major contributor to cancer, including glioblastoma, where amplification and mutation of epidermal growth factor receptor (EGFR) is common. The most common mutation is in-frame deletion of exons 2-7, known as EGFRvIII, EGFR* or ΔEGFR. EGFRvIII confers enhanced tumorigenicity on glioma cells in vivo, reducing apoptosis and increasing proliferation. EGFRvIII signals constitutively and at approximately 5-to-10-fold lower intensity than wild-type.
We are investigating the pathways that are preferentially activated by EGFRvIII, using a phosphotyrosine-directed, mass spectrometry-based shotgun phosphoproteomics approach in two different cell lines, LNZ308 (PTEN null) and LN428 (PTEN wt). We identified 433 proteins with 772 peptides out of which 249 proteins corresponding to 354 peptides showed tyrosine phosphorylation. Statistical analysis revealed several signals that were prevalent in EGFRvIII expressing glioma cells, including phosphorylation of STAT5, Gab1 and MIG6.
Identification of STAT5 as a target of EGFRvIII prompted an investigation of whether EGFRvIII is active in the nucleus. We have identified EGFRvIII associated with phosphorylated STAT5 on chromatin, and capable of activating the expression of STAT5 target genes, including Aurora A kinase, which positively regulate glioblastoma malignancy. STAT5 promotes expression of the EGFRvIII target gene Bcl-XL, and knockdown of STAT5 reduces the transformation induced by EGFRvIII. Furthermore, we have mutated signals in EGFRvIII that regulate nuclear localization, and are examining the impact of these on its ability to promote tumor growth.
In a related study we have used artificial receptor dimerization, mediated by technology from Ariad Pharmaceuticals, to enhance the EGFRvIII signal. A chimeric version of EGFRvIII was created, in which the receptor was fused N-terminally with two FKBP-F36V domains that could be activated by the chemical inducer of dimerization, AP20187. This has resulted in a more oncogenic form of EGFRvIII that emits a stronger signal, and we are using this to deepen our phosphoproteomics analysis to seek additional preferential targets of EGFRvIII action, which will be reported.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3125.
Abstract 3133: In vitro modeling of human pancreatic duct epithelial cell transformation
Authors: Leung Lisa H. , Radulovich Nikolina , Tsao Ming-Sound 
Published: February 2011

Abstract
Background: Pancreatic cancer is the fifth most common cause of cancer death in North America and has an overall 5-year survival rate of less than 5%. Over 90% of tumours are ductal carcinoma (PDAC), which putatively arise from the pancreatic ducts. In PDAC, KRAS oncogene activation occurs in approximately 90% of cases, while SMAD4 tumour suppressor gene inactivation occurs in around 55% of cases. We hypothesize that introduction of multiple genetic aberrations into pancreatic epithelial cells derived from normal ducts may provide a dynamic model to study pancreatic duct cell carcinogenesis.
Materials and Methods: We have isolated another cell line from the H6c7 immortalized near normal pancreatic duct epithelial (HPDE) cell line called TβR. TβR cells were generated by growing the H6c7 cells in progressively increasing concentrations of TGF-β and are resistant to growth inhibition by TGFβ. Overexpression of KRASG12V in TβR gave rise to TβR-KRAS cells.
Results: Spectral karyotypic analysis of TβR cells revealed paradiploidy but with the loss of one copy of chromosome 18, on which the Smad4 gene resides. Q-PCR and Western blot confirmed the lost of Smad4 expression in this cell line. TβR cells demonstrated increased invasiveness as compared to the parental H6c7 cell line, and this is further enhanced in TβR-KRAS cells. The TGF-β-Smad4 signaling pathway was disrupted in both the TβR and TβR-KRAS cell lines. This resulted in the loss of responsiveness to TGF-β and the repressed expression of Smad4 responsive genes. The subcutaneous injection of the TβR-KRAS induced in tumor growth in SCID mice.
Conclusion: The complete loss of Smad4 expression cooperates with KRASG12V oncogene to induce tumorigenicity in H6c7 cells. This provides a dynamic in vitro model to study the gene expression changes that characterize the key molecular events that occur during pancreatic ductal carcinogenesis. (Supported by the Canadian Institutes of Health Research grant MOP-49585)
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3133.
Abstract 3148: Translational control of lung cancer: eIF4E over-expression is not sufficient to confer tumorigenicity to human bronchial epithelial cells
Authors: McCauley Joel , Jacobson Blake , Bitterman Peter , Kratzke Robert , D'Cunha Jonathan 
Published: February 2011

Abstract
INTRODUCTION: Lung cancer is the leading source of cancer mortality in North America. There is an incomplete understanding of lung cancer tumorigenesis and new therapeutic targets are clearly needed. The role of 5’ cap-mediated translation in the control of cell growth and proliferation has become increasingly evident over the last decade. Enhanced cap-mediated translation has been implicated in multiple human malignancies including non-small cell lung cancer (NSCLC). Our group has shown that increased levels of eukaryotic initiation factor 4E (eIF4E) have been demonstrated in NSCLC and in vitro studies have shown that ectopic expression of eIF4E primary mammary epithelial cells enables clonal expansion and anchorage independent growth. Thus, our goal was to determine if over-expression of eIF4E would confer tumorgenicity to both normal human bronchial epithelial cells (NHBE), hTERT/Cdk4-immortalized human bronchial epithelial cells (HBECs), and SV40-transformed HBECs.
METHODS: Over-expression of eIF4E was stably induced by lentiviral transduction in NHBE, HBECs, SV40-transformed HBECs, and HBECs expressing lung cancer relevant oncogenes. Western blot was used to confirm eIF4E expression. Enhanced cap-mediated translation was confirmed by a cap-binding assay and soft agar assays were performed to determine anchorage independent growth. The stably transfected cells were injected into nude mice and evaluated for tumor formation.
RESULTS: Over-expression of eIF4E was accomplished by lentiviral transduction and shown to increase 5’ cap binding by cap-binding assay. Over-expression of eIF4E did not induce loss of cellular senescence in NHBEs. HBECs stably transformed with eIF4E did not exhibit anchorage independent growth. The over-expression of eIF4E in conjunction with p53 knockdown, K-RASV12, and c-myc did not confer in vitro evidence of tumorigenesis or lead to tumor formation in a xenograft model. Finally, the over-expression of eIF4E in SV40-transformed HBECs did not confer tumorigenesis in vitro or in vivo.
CONCLUSIONS: Over-expression of eIF4E in NHBEs, hTERT/Cdk-immortalized HBECs, and SV40-immortalized HBECs was not sufficient to induce tumorigenesis. Further, the addition of several key oncogenes did not drive transformation. Additional investigations are warranted to evaluate the important translational regulators in NSCLC tumorigenesis. The resistance to tumor formation seen in this study may provide important insight into the regulatory mechanisms present in bronchial epithelial cells routinely exposed to environmental carcinogens.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3148.
Abstract 3152: Sumoylation of eIF4E activates mRNA translation
Authors: Hu Jing , Xu Xiang , Vatsyayan Jaya , Gao Chenxi 
Published: February 2011

Abstract
Eukaryotic translation initiation factor 4E (eIF4E) is the cap-binding protein that binds the 5’ cap structure of cellular mRNAs. Despite the obligatory role of eIF4E in cap-dependent mRNA translation, how the translation activity of eIF4E is controlled remains largely undefined. Here we report that mammalian eIF4E is regulated by SUMO-1 (small ubiquitin-related modifier-1) conjugation. eIF4E is sumoylated on lysines 36, 49, 162, 206 and 212. Using eIF4E sumo-deficient mutant as a tool, we find that eIF4E sumoylation disrupts the interaction of 4IF4E with its inhibitor 4E-BP1 (eIF4E-binding protein 1) and promotes the eIF4E/eIF4G association. Further, downregulation of eIF4E sumoylation inhibits eIF4E-dependent protein translation of a subset of genes that are critical for cell proliferation and preventing apoptosis, and abrogates the oncogenic and anti-apoptotic functions associated with eIF4E. These data indicates that sumoylation represents a novel fundamental regulation mechanism of protein synthesis. Our findings further suggest that eIF4E sumoylation may be important in promoting human cancers.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3152.
Abstract 3164: Posttranscriptional regulation of opiate tolerance by OPRM1 splice variants following morphine/fig (Ficus carica) leaf extract treatment of human neuroblastoma (SH-SY5Y) cells
Authors: Lightbourn Alrena V. , Goodman Carl B. , Zhu Zhi-Ping 
Published: February 2011

Abstract
Aberrant splicing events have been implicated in a growing number of diseases, including cancer. The pharmacological significance of newly identified mu opioid receptor (MOR-1) alternative splice variants has not been characterized relative to drug response mechanisms and may inform the issue of morphine tolerance. Among the 70-90% of cancer patients requiring individualized opioid therapy for intense chronic pain, the response to prototypical opiates like morphine is highly variable, necessitating dose escalation with an increased risk of developing tolerance. It has been suggested that chronic morphine exposure has little, if any, effect on MOR-1 regulation. If this is true, then chronic exposure should also have no effect on variant forms of receptor. We therefore tested the hypothesis that, following chronic exposure to morphine and/or fig leaf extract, MOR-1 variants would be differentially regulated as evidenced by altered relative mRNA expression levels. Retinoic-acid differentiated human neuroblastoma (SH-SY5Y) cells were treated with morphine (10 µM), fig leaf extract (3 µL/30 mL media), or both for 48 hours before analysis by quantitative real-time polymerase chain reaction (qRT-PCR) using the Bio-Rad iCycler/MyiQ™. MOR-1 variant forms identified by analysis included: MOR1A, MOR1-B1, MOR1-B2, MOR1-B3, MOR1-B5, MOR1-K1. MOR1B4 expression was negligible. Variant mRNA expression was differentially regulated in 92% of the samples treated with fig leaf extracts from 7 cultivars (Green Ishia, Brown Turkey, Mission, Alma, Giant Celeste, Nero, Hollier). Fig administered alone up-regulated MOR-1 splice variant expression (1.6 to 16.9-fold), but these levels were suppressed in combination with morphine (0.2 to 0.8-fold). Also in combined treatment groups, MOR1-K1 and MOR1-B2 mRNA levels consistently up-regulated or down-regulated together. Morphine given alone down-regulated variant expression (0.2 to 0.7-fold). Closer inspection of MOR-1 alternative splice variants under experimental conditions appear to disqualify the assumption that MOR-1 receptor expression remains unchanged under chronic exposure conditions. The results of this study confirm our hypothesis that MOR-1 splice variants are differentially regulated following chronic exposure to morphine and other agents. Further examination of the functional role of MOR-1B2 and MOR1-K1 variants may contribute to our understanding of the mechanistic basis of morphine tolerance and may give clues as to the therapeutic benefit of targeting transcriptional isoforms the receptor for cancer pain relief.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3164.