bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4778: Epigenetic modulation of colorectal cancer cells for cancer-testis antigen-targeted immunotherapy
Authors: Chou Jeffrey , Voong Lilien N. , Chen Xiaoji , Yee Cassian , Warren Edus H. 
Published: February 2011

Abstract
Cancer-testis (C-T) antigens represent attractive potential targets for cancer immunotherapy due to their limited expression in normal somatic tissues and their widespread expression in malignant cells of diverse histologies. The utility of C-T antigens for immunotherapy of colorectal cancer (CRC), however, is limited because expression of C-T genes is repressed in most CRC cells by hypermethylation. We investigated whether treatment of CRC lines with the hypomethylating agent 5-aza-2′-deoxycytidine (DAC) could induce C-T gene expression in CRC cells and thereby sensitize them to recognition by CD8+ cytotoxic T lymphocytes (CTL) specific for the highly immunogenic C-T antigen NY-ESO-1.
A panel of CRC and primary dermal fibroblast lines was cultured with DAC or medium alone for 48 hours followed by culture with exposure to interferon γ (IFNγ) or medium alone for an additional 48 hours. After the treatment period, cells were harvested for collection of RNA, DNA, and protein; studied with flow cytometry for analysis of MHC class I and II expression; and tested for recognition by HLA-A*0201-restricted CTL specific for NY-ESO-1157–165 in a 51Cr release-cytotoxicity assay.
Quantitative RT-PCR analysis of the expression of 20 C-T genes in untreated and DAC-treated cells using a custom PCR array showed that the majority of C-T genes were expressed at low levels in untreated CRC cells but were induced in most CRC cell lines by DAC exposure. Fibroblasts did not show any significant C-T gene expression with or without DAC treatment. Western blot analysis for NY-ESO-1 expression confirmed that DAC induction of NY-ESO-1 transcription was also associated with increased protein expression. DAC-treated HLA-A*0201+ CRC lines were also recognized by CD8+ HLA-A*0201-restricted NY-ESO-1-specific CTL. CTL recognition was enhanced when the cells were treated with IFNγ in combination with DAC, with the most significant effect seen in CRC cells with low baseline expression of MHC class I molecules.
These data suggest that epigenetic modulation with DAC or related agents could be used to selectively induce expression of C-T antigens in CRC cells and thereby make them susceptible to C-T antigen-directed immunotherapy.
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 4778.
Abstract 4781: EGFR peptide-specific T cells in head and neck squamous cell carcinoma
Authors: Schuler Patrick J. , Boekers Petra , Engers Rainer , Arsov Christian , Greve Jens , Lang Stephan , Bier Henning , Whiteside Theresa L. , Hoffmann Thomas 
Published: February 2011

Abstract
In head and neck squamous cell carcinoma (HNSCC) expression of epidermal growth factor receptor (EGFR) correlates with poor prognosis and decreased survival rates. The cellular immune response to EGFR expression in vivo remains unclear.
The frequency of T-cells specific for HLA-A2.1 restricted to EGFR derived YLN peptide (YLNTVQPTCV) and KLF peptide (KLFGTSGQKT) was determined by corresponding tetramer/pentamer analysis in 18 HLA-A2.1+ HNSCC patients and 18 healthy HLA-A2.1+ individuals (NC). Patients’ results were correlated to EGFR expression obtained by immunohistochemistry in corresponding tumor sections. Proliferation and anti-tumor activity of peptide-specific T-cells was demonstrated by in vitro stimulation (IVS) with dendritic cells (DC) pulsed with the HLA-A2.1-restricted peptides.
For both EGFR peptides the average frequency of specific CD8+ T-cells (0.017% and 0.014%) was not significantly increased in the circulation of HNSCC patients compared to NC (0.019% and 0.014%). A large variability in the frequency of peptide-specific CD8+ T-cells was found in HNSCC patients (0.002 - 0.076%) and NC (0.002-0.134%). All (18/18) tumors showed EGFR expression. IVS with peptide-pulsed DC resulted in the expansion of EGFR-specific CD8+ T-cells, which were reactive against the EGFR+ cell line UD-SCC 8 in IFN-γ ELISPOT. T-cell expansion was significantly greater for the KLF-peptide than the YLN-peptide.
While EGFR peptide-specific T-cells were present in the circulation of HNSCC patients, their mean frequency was not increased to that in NC. Patients showed variable frequencies of peptide-specific T-cells. These T-cells were responsive in vitro to stimulation with the relevant EGFR peptides (YLN and KLF) and recognized EGFR+ tumor cells. Strategies for expansion of EGFR peptide-specific CTL may be important for future immunotherapy of HNSCC patients.
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 4781.
Abstract 4783: Identification of a novel TAA, SPARC, as a target for immunotherapy of various cancers
Authors: Inoue Mitsuhiro , Hirata Shinya , Senju Satoru , Ikuta Yoshiaki , Hayashida Yuki , Tsunoda Takuya , Furukawa Yoichi , Nakamura Yusuke , Nishimura Yasuharu , Baba HIdeo 
Published: February 2011

Abstract
It is important to identify Tumor-associated antigens (TAAs) to direct the immune system to attack cancer in order to establish efficient anti-cancer-immunotherapy. We analyzed the gene expression profiles of gastric cancers by using the genome wide cDNA microarray consisting of probes for 20,340 genes, and found that SPARC (Secreted Protein Acidic and Rich in Cysteine) gene was overexpressed in diffuse-type gastric cancer tissues at higher levels in comparison to adjacent normal gastric tissues. The levels of expression of SPARC in pancreatic cancer and colorectal cancer tissues were also higher than those of normal counterparts. On the other hand, the expression of SPARC among the normal tissue specimens was detected only in limited tissue specimens at very low levels. Therefore, we evaluated the possibility of SPARC as a target antigen for anticancer immunotherapy. This study attempted to identify HLA-A24 (A*2402)-restricted and SPARC derived CTL epitopes.
To identify the SPARC-derived and HLA-A24-restricted CTL epitopes, we selected a total of 4 different candidate 9- or 10- amino acid peptides that were expected to have a higher binding affinity to HLA-A24 (A*2402) by the HLA Peptide Binding Predictions in the BIMAS software program. The H-2 Kd-binding peptide motif is comparable to that of HLA-A24 binding peptide. Thus, we examined CTL response of BALB/c mice to these SPARC-derived epitopes. We found that two SPARC derived peptides elicited high magnitude of CTL response in BALB/c mice in an H-2Kd-restricted manner. Therefore, we attempted to generate SPARC-specific CTLs from the PBMCs of healthy donors and various cancer patients positive for HLA-A24 by stimulation of PBMCs with these two peptides. SPARC peptides-reactive CTLs were successfully induced from PBMCs by in vitro stimulation with these two peptides in HLA-A24 (A*2402) positive healthy donors and cancer patients. Moreover the SPARC-reactive CTLs established from PBMCs derived from cancer patients by stimulation with these two peptides, exhibited cytotoxicity to the cancer cells expressing both HLA-A24 and endogenous or transgene-derived SPARC. On the other hand, the CTLs did not kill the cells which were negative for either HLA-A24 or SPARC.
Furthermore, the adoptive transfer of the SPARC-specific CTLs could inhibit the tumor growth in NOD/SCID mice bearing human cancer cells expressing both HLA-A24 (A*2402) and SPARC. These findings suggest that SPARC is a potentially useful target candidate for cancer immunotherapy.
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 4783.
Abstract 4788: Modulation of T lymphocytes by tumor-released survivin
Authors: Slater Jessica M. , Khan Salma , Wall Nathan R. 
Published: February 2011

Abstract
Introduction: The role of tumor infiltrating lymphocytes (TILs) in the progression of cancer has become an important area of research. Recent studies have shown that T lymphocytes within the tumor microenvironment have decreased activation and proliferation. Our lab has shown survivin is released from tumor cells within exosomes, and is capable of altering the phenotype of malignant cells. We hypothesize that this exosomally-released survivin prevent TIL activation and proliferation in T cell subsets and that Th2 type cytokines will be released in higher levels than Th1 cytokines. Methods: HeLa-S-WT cells that produce Flag-HA tagged survivin were growth in a bioreactor and survivin isolated from the media using Flag-HA tandem affinity purification. T lymphocytes from normal donors were cultured in control or survivin-containing media and activated with anti-CD28-anti-CD3 microbeads (32 ul/ml). Flow cytometric analysis of activation marker CD69 and the proliferation marker Ki-67 were performed at 24h and 6 days, respectively. Cytokine release was evaluated using a Cytokine Bead Array (BD Bioscience) for IFN-gamma, IL-2, IL-4 and IL-10. Results: CD69 expression was decreased significantly in CD8+ T cells after incubation with survivin (Control = 72 MFU, Treated = 57 MFU; p&lt;0.05) while no significant change was seen in CD4+ T cells (Control = 65 MFU, Treated = 68 MFU). CD8+ T cells showed a significant reduction in Ki-67 expression after incubation with survivin when compared to controls (Control = 218 MFU, Treated = 139 MFU; p &lt; 0.001), while CD4+ T cells showed little difference between control and treated groups (Control = 74 MFU, Treated = 81 MFU). Cells treated with survivin in activating conditions released higher amounts of IL-4 (Control = 4.8 pg/ml, Treated = 28.3 pg/ml) and decreased amounts of IFN-gamma (Control = 32.4 pg/ml, Treated = 16.9 pg/ml) compared to control activating conditions. IL-2 and IL-10 showed little difference between treatment groups. Conclusions: This data suggests that survivin in the tumor microenvironment is capable of negatively affecting cytotoxic T cell activation and proliferation. While survivin treatment does not affect the activation or proliferation of CD4+ subsets, the Th1: Th2 cytokine balance is altered when survivin is present. Thus, survivin in the tumor microenvironment could play a role in the suppression of immune surveillance by inhibiting the cytotoxic T cell response and preventing tumor death by increasing levels of Th2 cytokines and decreasing levels of Th1 cytokines.
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 4788.
Abstract 479: p53 mutations and Ink4a/Arf deletion cooperate to induce metastatic skin carcinomas
Authors: Li Zhongyou , Mejia Olga , Caulin Carlos 
Published: February 2011

Abstract
Mutations in the p53 tumor suppressor gene are found in about half of the squamous cell carcinomas (SCC) that arise in the skin and oral cavity. Most of these mutations are missense mutations that result in the expression of altered forms of p53, some of which acquire oncogenic properties. We previously showed that the p53 gain-of-function mutation p53R172H cooperates with Ras activation during skin cancer initiation, progression to carcinoma and metastasis. However, it is unclear whether p53 gain- and loss-of-function mutations predispose differently to SCC formation when activated in the absence of additional oncogenic mutations. To address this question we generated mice in which deletion of p53 (loss-of-function) or activation of the p53R172H mutation (gain-of-function) were induced in mouse stratified epithelia. We found that over 70% of the mice developed skin or oral SCCs, with similar kinetics for mice with p53 gain- or loss-of-function mutations, suggesting that in the absence of Ras mutations the oncogenic role of p53R172H in SCC initiation is minimized. To identify mechanisms leading to SCC development in these mice we analyzed the status of pathways that are frequently involved in human SCCs. We observed that Erk1/2 activation was blocked in most of the SCCs. Consistently, oncogenic mutations in Ras genes were only found in &lt;5% of the SCC analyzed. Notably, we found overexpression of cyclin D1 and activation of Akt in over 50% of the SCCs, suggesting an important contribution for these oncogenic alterations in SCC development in these mice. Importantly, p16INK4a and p19ARF were overexpressed in most of the SCCs, suggesting that in the absence of p53, alternative tumor suppressor mechanisms are activated to prevent tumor progression. To determine whether p53 mutations and p16/p19 cooperate in SCC formation we generated mice in which p53 mutations and deletion of the Ink4a/Arf locus were induced in the epidermis. These mice developed skin carcinomas significantly faster than mice with mutations in p53 only. In addition, in the presence of the Ink4a/Arf deletion, the p53R172H mutation induced accelerated SCC formation compared to deletion of p53, again suggesting that the oncogenic properties of mutant p53 are exposed in the presence of additional genetic alterations. The tumors that developed in these mice were classified as spindle cell carcinomas (SPCC) and generated metastasis in over 60% of the mice. Ongoing experiments are underway to identify molecular mechanisms involved in the generation of SPCCs and metastasis in this model.
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 479.
Abstract 4791: Inhibition of Tumor Formation in Mice following Vaccination with DNA Encoding a Novel Xenogeneic Tumor Associated Auto-Antigen
Authors: Bright Robert K. , Bright Jennifer D. , Schultz Heather N. 
Published: February 2011

Abstract
Tumor protein D52 (TPD52) is a novel auto-antigen involved in cellular transformation, proliferation and metastasis. Its over-expression has been demonstrated in several human malignancies including prostate, breast, and ovarian carcinomas. Murine TPD52 (mD52) has been shown to induce anchorage independent growth in vitro and spontaneous metastasis in vivo. Importantly, mD52 mirrors the function and normal tissue expression patterns of the human orthologue of TPD52 (hD52) and shares 86% identity at the amino acid level. Thus, TPD52 represents a self, non-mutated tumor associated auto-antigen that is important for maintaining a tumorigenic phenotype. The Transgenic Adeno-carcinoma of the Mouse Prostate (TRAMP) model was employed to study TPD52 as a vaccine antigen. Naïve mice were immunized with either mD52 or hD52 DNA. Following immunization, mice were challenged with a subcutaneous, tumorigenic dose of mD52 positive, autochthonous TRAMP-C1 tumor cells. Greater than 70% of mice were tumor free more than 10 months post tumor challenge when immunized with hD52 as a xenogenic DNA vaccine. Survivors of the initial tumor challenge rejected a second tumor challenge with TRAMP-C2 tumor cells given in the opposite flank approximately 138 days after the first challenge with TRAMP-C1, and remained tumor free for more than 6 months. The T cell cytokine secretion patterns from tumor challenge survivors indicated that a cellular immune response was involved in tumor rejection. These data suggest that hD52 xenogeneic DNA vaccination induced a memory, cellular immune response that resulted in superior protection from challenge with murine prostate-derived tumors that naturally over-express mD52 protein.
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 4791.
Abstract 4799: Epigenetic antagonism between Polycomb and SWI/SNF complexes during oncogenic transformation
Authors: Wilson Boris G. , Shen Xiaohua , McKenna Elizabeth S. , Wang Xi , Cho Yoon-Jae , Koellhoffer Edward C. , Nguyen Phuong T.L. , Pomeroy Scott L. , Orkin Stuart H. , Roberts Charles W.M. 
Published: February 2011

Abstract
Epigenetic alterations serve critical roles in cell fate decisions and have increasingly been implicated in cancer formation. The Polycomb Group (PcG) protein EZH2 mediates epigenetic gene silencing, displays pro-oncogenic properties in cell lines and is frequently overexpressed in cancer. Conversely, loss of function mutations in the tumor suppressor gene SNF5, a core subunit of the SWI/SNF chromatin remodeling complex, occur in several types of aggressive human cancers. Intriguingly, analysis of homeotic mutants in Drosophila suggests that PcG and SWI/SNF can serve antagonistic roles in the epigenetic control of gene expression. Here we have investigated functional relationships between these epigenetic regulators in oncogenic transformation by examining the role of EZH2 in tumors driven by SNF5 loss. Notably, SNF5-mutant tumors, despite being highly aggressive, are diploid and genomically stable, making them an ideal model with which to elucidate epigenetic drivers of oncogenesis. We show that targeted inactivation of Snf5 leads to increased expression of Ezh2 and that EZH2 is upregulated in SNF5- deficient cancers. A key mechanism by which SNF5 loss promotes oncogenesis is via downregulation of the p16INK4a tumor suppressor. We show that inactivation of Ezh2 restores normal levels of p16INK4a to Snf5-deficient fibroblasts. We further show that reducing the levels of EZH2 in a human SNF5-deficient tumor cell line leads to increased levels of p16INK4a accompanied by slowed proliferation and cellular senescence. Most importantly, using conditional mouse models, we show that inactivation of EZH2 completely blocks tumor formation driven by SNF5 loss. Our results demonstrate an essential role for Ezh2 in oncogenic transformation in vivo and show that perturbing the epigenetic balance of gene expression mediated by EZH2 silencing and SWI/SNF activation can have a profound effect on tumor formation. Further, we establish that targeted inhibition of EZH2 in vivo can have potent anti-cancer effects.
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 4799.
Abstract 4803: A novel mitochondrial isoform of mammalian DNA methyltransferase 1
Authors: Shock Lisa M. , Thakkar Prashant V. , Peterson Erica J. , Moran Richard G. , Taylor Shirley M. 
Published: February 2011

Abstract
Cancer cells, in contrast to normal cells and tissues, fulfill their energy requirements by increased glycolysis, with a distinct downregulation of oxidative phosphorylation in the mitochondria. Regulation of enzymes of the glycolytic pathway under the anoxic conditions prevalent in human solid tumors by stabilization of HIF1α have been intensely investigated; however, the mechanisms regulating transcription of the mitochondrial genome, and its coordinate regulation with the nuclear genome are less well understood. Eukaryotic mitochondrial DNA carries a low but significant level of cytosine methylation, but molecular mechanisms responsible for the generation of this modification and its role in mitochondrial function has not been studied. The mitochondrial genome encodes 13 polypeptides involved in oxidative phosphorylation, as well as the tRNAs and rRNAs required for mitochondrial translation. All other proteins required for mitochondrial function are encoded by the nuclear genome and translocated to the mitochondria using mitochondrial targeting sequences frequently located at the N-terminus. We have identified a novel isoform of mammalian DNA methyltransferase 1 (DNMT1) that translocates to the mitochondrion, using a conserved N-terminal mitochondrial targeting sequence; the mRNA encoding this isoform is expressed from an upstream transcription start site. De novo methyltransferases DNMT3a and DNMT3b are not found in mammalian mitochondria. Expression of the mitochondrial DNMT1 isoform (mtDNMT1) is regulated by nuclear respiratory factor 1 (NRF1) and coactivator PGC1α, which together upregulate several nuclear-encoded mitochondrial genes involved in the electron transport chain, following hypoxic stress. The mitochondrial isoform (mtDNMT1) is also preferentially upregulated following loss of p53 function, leading to specific effects on mitochondrial gene expression and potentially affecting mitochondrial function. We therefore suggest that mitochondrial DNA methylation, established and maintained by mtDNMT1, plays a role in coordination of mitochondrial gene expression and that the expression of the mtDNMT1 isoform is under the control of p53.
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 4803.
Abstract 4805: A quantitative high-throughput screen identifies novel potential epigenetic modulators of gene transcription
Authors: Wichterman Jennifer L. , Huang Ruili , Huang Wenwei , Austin Christopher , Inglese James , Martinez Elizabeth , Johnson Ronald 
Published: February 2011

Abstract
Epigenetic regulation of gene expression is important in many biological processes including tumor formation. While some key modulators of epigenetic control like histone deacetylases and DNA methyltransferases are the subject of intensive research, little else is known of other targets or modifications that regulate this process. We used an image-based cell assay that measures induction of a silenced GFP-estrogen receptor (ER) reporter to identify novel classes of compounds involved in epigenetic regulation. This Locus Derepression (LDR) assay was screened against 282,000 compounds using quantitative high-throughput screening, a method that assays compounds at multiple concentrations. Structure-activity relationships of the 680 actives recovered from the screen indicated 127 clusters and 110 singletons. Over 200 compounds were retested in the LDR cells and were counter-screened against the parental line to identify fluorescent artifacts. Of the 72 compounds that retested as active and nonfluorescent, 57 were tested as independent samples to confirm activity. Confirmation studies indicated 23 compounds showed consistent activity in LDR cells and were not fluorescent. Confirmed actives are being characterized further to identify the targets and pathways these molecules modulate. These compounds represent important tool compounds for understanding the molecular mechanisms of epigenetic control of transcription.
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 4805.