bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 3208: Semaphorin 3F suppresses telomerase activity
Authors: Drenberg Christina D. , Bermudez Yira , Nicosia Santo V. , Kruk Patricia A. 
Published: February 2011

Abstract
Objectives: Telomerase is a ribonucleoprotein that is active in more than 90% of human tumors, including ovarian cancers. We have previously demonstrated that vascular endothelial growth factor (VEGF) stimulates telomerase activity in ovarian cancer cell lines through cellular VEGF receptors and the ERK1/2 pathway targeting Sp1 sites within the hTERT promoter. Since semaphorin 3F (S3F), a proposed tumor suppressor, has been shown to antagonize VEGF, the purpose of this study was to determine whether S3F inhibits telomerase
Methods: Telomerase-positive ovarian cancer cell lines (OV2008, C-13, SW626) and telomerase-negative non-tumorigenic, SV-40 large-T antigen-transfected human ovarian surface epithelium (HOSE) cell lines were evaluated for endogenous RNA and protein expression of S3F, VEGF, and their shared receptors. Cultured cells were either treated with recombinant S3F protein or transiently transfected with cDNA to over-express S3F. Conversely, these cells were transiently transfected with siRNA targeting S3F ± specific receptor inhibitors. RT-PCR and western blot confirmed S3F over-expression, knock-down of S3F, or inhibition of receptors. Telomerase activity was measured by telomerase PCR-ELISA, while RT-PCR and western immunoblotting were utilized to detect S3F as well as to explore the signaling pathway involved in S3F-mediated telomerase regulation.
Results: Telomerase activity was suppressed in ovarian cancer cell lines following treatment with S3F recombinant protein or S3F over-expression by transient transfection. Furthermore, siRNAs targeting S3F and NP-2 or treatment with the VEGF receptor inhibitor, CBO-P11, abrogated S3F mediated telomerase inhibition. Over-expression of S3F resulted in up-regulation of phosphorylation of Erk1/2.
Conclusions: These data suggest that telomerase is a novel molecular target of S3F. Since, angiogenic and angiostatic factors play an important role in ovarian cancer tumorigenesis, S3F-mediated inhibition of telomerase represents a potential novel target for therapeutic intervention.
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 3208.
Abstract 3209: The WRN RecQ helicase acts as a tumor suppressor in pancreatic adenocarcinoma
Authors: Chun Stephen G. , Yee Nelson S. , Qi Fang , Allsopp Richard , Davy Philip M. , Fong Keith S. , Carbone Michele , Bryant-Greenwood Peter K. 
Published: February 2011

Abstract
The vast majority of pancreatic adenocarcinoma is diagnosed in the geriatric population, and genes involved in cellular senescence such as the WRN-encoded RecQ helicase/exonuclease may be involved in pancreatic oncogenesis. Accumulating evidence suggests that WRN is a tumor suppressor gene (TSG), as a variety of cancers including pancreatic adenocarcinoma are associated with its epigenetic silencing or loss-of-function mutations. We hypothesize that wild-type WRN protects pancreatic epithelia from malignant transformation by regulating cell cycle progression and cell growth. First, we characterized a pancreatic adenocarcinoma cell line established from a human cadaver with Werner's syndrome (WS-Panc). WS-Panc had two loss-of-function mutations of WRN, formed adherent colonies in vitro, and expressed the pancreatic ductal epithelial marker cytokeratin 7. No oncogenic mutations of the epidermal growth factor receptor (EGFR), K-Ras nor B-Raf were detected by polymerase chain reaction (PCR), and immunologic assays revealed over-expression of lysyl oxidase-like 2, p53, and ß-catenin in WS-Panc. Fluorescent in situ hybrdization showed that WS-Panc over-expresses EGFR. Cytogenetic analyses showed normal karyotype. Strong telomerase activity was detected in WS-Panc by the Telomere Repeat Amplification Protocol. To test the hypothesis that WRN is a TSG, we forced ectopic expression of wild-type WRN in WS-Panc and are analyzing the biological properties and molecular features of transfected cells. Consistent with an anti-proliferative effect, wild-type WRN mRNA levels are uniformly repressed in a panel of sporadic pancreatic cancer cell lines from the American Type Culture Collection as shown by quantitative real-time PCR. In summary, we provide evidence that WRN is a TSG in pancreatic epithelia using WS-Panc and other pancreatic cancer cell lines. WS-Panc is the first cancer cell line carrying WRN loss-of-function mutations that represents a unique translational resource to elucidate WRN in the neoplastic state. Ongoing investigation of WRN in primary pancreatic cancer tissue and tumor models in vivo are expected to elucidate mechanistic links between aging and pancreatic cancer for the purpose of developing efficacious interventional strategies.
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 3209.
Abstract 321: Chromosomal and molecular genomic analysis of spontaneously transformed murine colon epithelial cells
Authors: McNeil* Nicole E. , Padilla-Nash* Hesed M. , Nguyen Quang Tri , Ried Thomas 
Published: February 2011

Abstract
Introduction: Colorectal cancer (CRC) represents one of the most common malignancies in the United States. The pathological progression from adenoma to carcinoma is accompanied by distinct and reproducible genetic alterations. Here we present a novel mouse model system for the sequential steps of tumorigenesis. This system will be helpful for functional validation of novel therapeutic targets in CRC.
Purpose: The aim of this study is to delineate the stage-specific genomic alterations and transcriptional deregulation that are associated with the spontaneous progression of normal murine colon epithelial cells to immortalized, transformed, and eventually tumorigenic cell lines.
Methods: Normal epithelial colon cells were selectively isolated from the large intestine from eight different isogenic five-six week old C57BL/6 mice. Primary colon cells were grown with reduced serum concentration while a fraction of these normal cells were cryopreserved for further analysis. The cells were sequentially recovered from culture based on distinct morphological changes: first, when the cells were in the pre-immortal stage as cells were actively growing; second, as the cells bypassed crisis, formed colonies and became immortal; third, at early transformation, as the cells first formed foci; fourth, mid-transformed (higher proliferation rates, later passages); and finally, as cells became less adherent, and exhibiting multiple foci. The cells were then analyzed using molecular cytogenetic methods (SKY and arrayCGH), and using global gene expression profiling.
Results: Using Spectral Karyotyping (SKY) we identified clonal chromosomal aberrations and recurrent chromosome imbalances, specifically reported here for late transformed cells and in tumor cells. Array CGH (aCGH) demonstrated a specific pattern of whole chromosome copy number gains (i.e. MMU10 and MMU15 which contain Mdm2 and Myc, respectively) and losses (ex. MMU4 which contains tumor suppressor gene p16/Ink4a/Cdkn2a) at the various stages of cellular transformation. Gene expression microarray identified the deregulation of specific genes that defined genomic signatures at each stage of transformation. Two of the eight late transformed cell lines gave rise to tumors in a nude mouse assay.
Conclusion: We present a novel mouse model of CRC that recapitulates the sequential steps of human colorectal tumorigenesis which affords us the possibility to experimentally test potential rational intervention strategies.
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 321.
Abstract 3213: GRHL2 enhances hTERT transcription by inhibiting promoter DNA methylation at 5’ CpG island
Authors: Chen Wei , Dong Qinghua , Shin Ki-Hyuk , Kim Reuben H , Oh JE , Park No-Hee , Kang Mo Kwan 
Published: February 2011

Abstract
We recently identified Grainyhead-like 2 (GRHL2), a mammalian homologue of Grainyhead in Drosophila, to be a novel transcription factor that binds to and regulates the activity of the human telomerase reverse transcriptase (hTERT) gene promoter. In the current study, we investigated the biological function of GRHL2 in normal human keratinocytes (NHK) and elucidated the molecular mechanism underlying GRHL2 regulation of hTERT gene expression. Primary NHK were infected with retroviral vectors expressing GRHL2 or the empty vector. GRHL2 transduction led to significant extension of the replicative lifespan of NHK by evading the senescence block. However, GRHL2 failed to cause immortalization of NHK, alone or in combination with Bmi-1, a polycomb group protein that bestows extended replication capacity to NHK. Enhanced proliferation of cells transduced with GRHL2 was also observed in three dimensional organotypic raft culture. Telomerase activity was detected in replicating NHK while it was rapidly lost during senescence. GRHL2 transduction increased the expression of hTERT and maintained detectable telomerase activity for extended time period, suggesting that GRHL2 positively influences the hTERT expression and telomerase activity in NHK. Upon knockdown of endogenous GRHL2, hTERT mRNA expression and telomerase activity were notably reduced. We previously showed that hTERT expression in NHK is regulated in part by promoter methylation at the 5’ CpG island. Thus, we determined the effects of GRHL2 on the methylation status of hTERT promoter by methylation-specific PCR (MSP). Loss of hTERT expression in the control NHK occurred with hTERT promoter hypermethylation. On the contrary, GRHL2 transduction notably reduced the extent of promoter methylation in NHK. This effect was not linked with enhanced cell proliferation because Bmi-1 transduction in NHK, which allowed prolonged cell proliferation, showed no effect on the hTERT promoter methylation. These data indicate that GRHL2 inhibits the promoter DNA methylation, thereby delaying hTERT gene inactivation and senescence of NHK. This study was supported by the grants R01DE18295, K02DE18959 from NIDCR/NIH.
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 3213.
Abstract 3217: Regulation of senescence-associated p-Erk1/2 (SA-p-Erk1/2) by PEA-15 and PKC-α in human diploid fibroblasts
Authors: Lee Yun Yeong , Kim Hong Seok , Choi Yong won , Lim In-Kyoung 
Published: February 2011

Abstract
Cellular senescence plays a key role in complicated biological processes, including development, aging, and tumorigenesis. Hallmarks of cellular senescence are metabolically active but not responsive to mitogens, therefore, decreased cell growth, cell cycle arrest, and reached to the flat and large cell shapes. We have recently reported that high expression of senescence-associated p-extracellular signal-regulated protein kinase 1/2 (SA-pErk1/2) can induce p21WAF1 expression via the activation of a transcription factor, SP1. In the present work, we investigated a biochemical regulation of the cytoplasmic sequestration of SA-pErk1/2 and found that PEA-15 (phosphoprotein enriched in astrocytes-15) could regulate translocation of SA-pErk1/2 to nuclei along with activation of PKC-α in senescent cells. It was proved by treatment of senescent cells with 12-O-tetradecanoylphorbol-13-acetate (TPA), which phosphorylated PEA-15 upon Ser104 residue via activation of PKC-α, which lead to release of SA-pErk1/2 form PEA-15 and then accompanied with nuclear translocation of SA-pErk1/2 along with PKC-α. Here, we, report the mechanism of cytoplasmic sequestration of SA-pErk1/2 and the relationship between PEA-15 and PKC-α in senescent human diploid fibroblasts (HDFs).
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 3217.
Abstract 3221: Analysis of the relationship between autophagy and senescence in response to Adriamycin in breast tumor cells
Authors: Di Xu , Henderson Scott C. , Gewirtz David A. 
Published: February 2011

Abstract
Autophagy is a conservative biological process, which involves the degradation of intracellular components (proteins or organelles) via the fusion of autophagosomes with lysosomes. Autophagy has been reported to have both cytoprotective and cytotoxic actions in response to either chemotherapy or radiation in different tumor model systems. In previous studies (Elmore LW et al., J Biol Chem. 2002 Sep 20; 277(38): 35509-15.), Adriamycin (doxorubicin), one of the primary chemotherapeutic drugs utilized in the treatment of breast cancer, was shown to induce a pronounced senescence response within 72hrs in MCF-7 breast tumor cells (at a clinically relevant concentration of 1μM, with a 2 hr exposure). Interestingly, Adriamycin was also observed to cause a time-dependent increase of autophagy within 72hrs (by acridine orange, Monodansylcadaverine) staining and electron microscopy). The current study was designed to evaluate the relationship between Adriamycin-induced autophagy and senescence in MCF-7 breast tumor cells. The antioxidants, GSH (glutathione) and NAC (N-acetyl cysteine), were previously shown to effectively block Adriamycin-induced senescence (Di X. et al., Biochem Pharmacol. 2009 Apr 1; 77(7):1139-50.). We now demonstrate that both GSH and NAC also effectively abolish Adriamycin-induced autophagy in MCF-7cells (as confirmed by the disappearance of punctuated red fluorescence staining (RFP-LC3) induced by Adriamycin. Unexpectedly, however, the autophagy inhibitors, 3-MA or wortmannin, failed to block Adriamycin-induced senescence (based on β-Gal staining). Another autophagy inhibitor, chloroquine, showed a significant blockade to β-Gal staining, although typical senescence morphology phenotypes, such as cell enlargement and flattening were still observed by phase contrast microscopy. Silencing of the autophagic protein, ATG5, failed to completely block Adriamycin-induced senescence, although the MCF-7/ATG5 knockdown cells showed decreased and delayed β-Gal staining. Taken together, our studies suggest that that autophagy proceeds and may contribute to the development of Adriamycin-induced senescence. The fact that blockade of senescence (by reactive oxygen scavengers) abrogates Adriamycin-induced autophagy further suggests that senescence and autophagy may be collaterally regulated in response to Adriamycin in MCF-7 cells. Both autophagy and senescence may be related to tumor dormancy (Gewirtz DA, Autophagy. 2009 Nov 24; 5(8).). Further studies are in progress to delineate the roles (cytoprotective or cytotoxic) of autophagy and the relationship of autophagy to senescence, tumor dormancy and sensitivity to chemotherapy and radiation.
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 3221.
Abstract 3223: Severe dietary restriction enhances cancer treatment: Protecting normal cells and sensitizing malignant cells to chemotherapy by fasting
Authors: Lee Changhan , Safdie Fernando , Raffaghello Lizzia , Wei Min , Longo Valter 
Published: February 2011

Abstract
Chemotherapy is a standard treatment modality for many cancers. However, its full clinical potential is greatly limited by toxic side-effects manifested as myelosuppression, gastrointestinal damage, fatigue, and in some case even death. Therefore, strategies or interventions that can selectively protect normal cells but not cancer cells will increase the therapeutic index of chemo drugs. We have previously reported that fasting can selectively protect tumor-bearing mice but not the cancer cells from chemo toxicity by down-regulating growth factors including IGF-I and its downstream pathways involving AKT/TOR and Ras. Here, using dietary and genetic interventions in yeast, mammalian cell culture, and mice, we show evidence that fasting not only provides selective protection to normal cells but may also sensitize certain cancer cells to chemotherapy or the severe dietary restriction itself.
Using mouse models of cancer, fasting for 48-hours was sufficient to drastically suppress tumor progression. In a mouse model of breast cancer, fasting alone caused more than a 50% decrease in tumor growth. Furthermore, when combined with chemotherapy, fasting sensitized cancer cells to chemo drugs and was able to further reduce tumor growth up to 90% compared to controls. In parallel, in vitro studies using these breast cancer cells revealed similar results where glucose restriction was sufficient to reduce proliferation and also sensitize the cells to 2 different types of the standard drugs for breast cancer treatment, doxorubicin and cyclophosphamide. Comparable results were obtained using mouse models of glioma, neuroblastoma and melanoma. Furthermore, in a metastatic model of melanoma, fasting/chemotherapy not only extended survival time, but also resulted in fewer organs affected by metastasis. Since chemotherapy is generally administered as a combination of drugs, we tested the effect of fasting on a cocktail of drugs in neuroblastoma-bearing mice and demonstrated significantly enhanced survival accompanied by reducing both drug toxicity and metastasis. In addition, we provide evidence that this protection is due to reduced DNA damage to normal cells. In fact, in our yeast studies, the deletion of the AKT/S6K homolog Sch9 or RAS provides enhanced protection against multiple types of chemotherapy-induced DNA mutations.
Considering the global increase in elderly population and that aging is the major risk factor for cancer, differential protection of normal cells concurrently with selective sensitization of malignant cells to chemotherapy may prove to be beneficial in cancer treatment.
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 3223.
Abstract 3224: Preclinical PKPD modeling and human dose projection of PF-04691502, a PI3K/mTOR dual inhibitor
Authors: Luu Kenneth T. , Zhang Eric , Bagrodia Shubha , Yuan Jing 
Published: February 2011

Abstract
PF-04691502 is a potent dual inhibitor of PI3K and mTOR, which are involved in regulating cell growth, proliferation and survival. The main objective of this work was to develop a preclinical pharmacokinetic-pharmacodynamic (PKPD) model for the compound and project the human efficacious dose. The PK of PF-04691502 in mouse obtained following oral dosing was described by a linear 2-compartment model which was used to drive two separate PD models: 1) an exponential growth model describing the tumor growth inhibition (TGI) and 2) an indirect-response model describing changes in intratumoral pAKT-S473/AKT in the U87MG xenograft mouse model. Based on the PK model, the half-life calculated from the linear elimination constant (k = 0.306 hr−1) was 2.3 hr and the plasma-compartment volume of distribution was 8.72 L/kg. The inter-compartmental distribution rate constants were 0.282 hr−1 and 0.212 hr−1 for k12 and k21, respectively. The model estimated in-vivo potency (IC50) for pAKT-S473/AKT suppression was 38.3 nM which was within the range of the IC50 (23 nM) for TGI (as parameterized by the model). The Imax estimated from the model was 0.975 (or 97.5%), which indicated nearly complete suppression of pAKT-S473/AKT production rate by PF-04691502. Based on the PKPD model and the scaled human PK, a clinical dose of 10 mg QD was determined to be adequate for maintaining the level of pAKT-S473/AKT below 50% of baseline. At steady-state PK this dose yielded a range of 50-80% human pAKT-S473/AKT suppression over the 24 hr dosing interval. In conclusion, PF-04691502 was determined to have a robust PKPD relationship in the preclinical animal model and was projected to have a clinically achievable efficacious dose of approximately 10 mg QD.
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 3224.
Abstract 3226: Targeting PI3K signaling in a xenograft model of nasopharyngeal carcinoma
Authors: Merritt David M. , Smith Pamela , Thorley-Lawson David A. 
Published: February 2011

Abstract
Nasopharyngeal carcinoma (NPC) is a cancer of the head and neck and is particularly common in Southern China and parts of the developing world. NPC may be a significant world health problem since it is likely to be underreported in parts of Southeast Asia and North Africa. The nonkeratinizing forms of nasopharyngeal carcinoma are divided into two subtypes based on histology (“differentiated” WHO type II and “undifferentiated” WHO type III.) Our analysis of gene expression data from an Affymetrix study of type II and type III NPC tumor biopsies using the Connectivity Map, a bioinformatics algorithm developed at the Broad Institute, suggests that the PI3K-Akt-mTOR pathway may be more highly activated in NPC type III. The array data may also reflect differential sensitivity to PI3K-Akt-mTOR pathway inhibitors and that the underlying genetic lesions that drive Akt activity in NPC type II and NPC type III are different. In addition, analysis using an algorithm that analyzes sets of functionally related genes, Gene Set Enrichment Analysis (GSEA), revealed that in NPC type III tumors, there is an increased expression of genes associated with epithelial-mesenchymal transition (EMT); a developmental program characterized by loss of cell adhesion, repression of E-cadherin expression and increased cell mobility. EMT has been reported to be a feature of several metastatic cancers. We performed biochemical assays in vitro on NPC cells that supported these findings, and then developed a xenograft tumor model that replicates invasive and metastatic NPC in immunodeficient mice. This model allows us to track tumor development by bioluminescence non-invasively over time. Blocking the PI3K-Akt-mTOR signaling pathway with Rapamycin, an mTOR inhibitor, had a significant effect on the growth of metastases.
Taken together, this suggests that the activation of the PI3K-Akt-mTOR pathway and EMT in NPC type III tumors may provide a molecular basis for the distinction between NPC type II and NPC type III, and that the type III phenotype is associated with metastatic progression in nasopharyngeal carcinoma. It may also provide prognostic and therapeutic implications for more efficacious treatment specifically targeting metastasis in NPC.
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 3226.