bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 1941: Cancer-driven exhaustion of tumor-reactive γδ-T cells: Relevance to immunosurveillance and immunotherapy
Authors: Beck Benjamin H. , Kim Hyung-Gyoon , Haines Hilary , Feeley Kyle , Lopez Richard 
Published: February 2011

Abstract
In contrast to antigen-specific αβ-T cells (adaptive immunity), γδ-T cells can recognize and lyse malignantly-transformed cells almost immediately upon encounter in a manner that does not require the recognition of tumor-specific antigens (innate immunity). Given the well-accepted capability of γδ-T cells to innately kill a variety of cancerous cells, efforts are now actively underway to develop and refine the means by which to exploit the antitumor properties of γδ-T cells for clinical purposes. Here, we investigated a critical issue surrounding γδ-T cell-based cancer immunotherapies, which relates to the findings that γδ-T cells are numerically rare in the peripheral blood of some cancer patients, and only in a proportion of patients is it possible to activate and/or expand γδ-T cells either in vivo or ex vivo regardless of the methodology employed. This is in stark contrast to what is observed in healthy individuals, as γδ-T cells reliably respond to proliferative stimuli. Indeed, it is evident that such numerical or functional deficits may greatly hinder attempts to employ γδ-T cells in clinical settings. Therefore, the objective of the studies performed here was to examine the biological underpinnings that may explain the γδ-T cell impairments observed in cancer patients. To this end, we employed murine models of different malignancies (breast cancer, myeloma, and melanoma) and systematically examined γδ-T cell numbers in peripheral circulation, γδ-T cell proliferative capacity, and overall γδ-T viability and apoptosis status in healthy mice and mice bearing different tumors. We found that tumor-bearing mice had fewer γδ-T cells in peripheral blood, and γδ-T cells derived from tumor-bearing mice expanded poorly ex vivo using published expansion regimens. Importantly, we show that tumor cells were responsible for this numerical and functional exhaustion of γδ-T cells. Using both in vitro and in vivo models of different cancers we demonstrate that γδ-T cells undergo apoptosis after encounter with tumor cells and we have identified several putative genes involved in this γδ-T cell exhaustion. We propose that this cancer-associated γδ-T cell impairment could serve as a critical early event leading to impaired γδ-T cell anti-tumor immunosurveillance, which may contribute to the accelerated development or progression of different malignancies. Collectively, these findings will help facilitate the development of the next generation of clinical trials designed to exploit the tumor-reactive properties of γδ-T cells.
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 1941.
Abstract 1942: Vδ1+ γδ T cells are cytotoxic against glioblastoma multiforme
Authors: Knight Andrea , Arnouk Hilal , Britt William , Gillespie G Yancey , Lowdell Mark W. , Cloud Gretchen A. , Markert James M. , Langford Catherine P. , Su Yun , Lamb Lawrence S. 
Published: February 2011

Abstract
Prior evidence of cytomegalovirus (CMV) infection has been documented in a large proportion of high-grade brain tumors such as glioblastoma multiforme (GBM), suggesting a potential role for CMV infection in GBM pathogenesis. Vδ2+ γδ T cells, which recognize tumor-derived mevolonate metabolites, have been shown to be highly cytotoxic to GBM cell lines and primary tumor explants. The specific role of Vδ1+ T cells, which respond to CMV infected cells in immunosuppressed patients and recognize NKG2D ligands MIC A/B and UL-16 binding proteins (ULBP), has not previously been investigated.
Vδ1+ T cells were purified (93-95%) from CMV+ and CMV- donors by immunomagnetic selection and cultured on irradiated allogeneic MNC in RPMI + 10% human serum (HS) supplemented with phytohemagglutinin (PHA) and 200U IL-2. Vδ2+ T cells were expanded from mononuclear cells in RPMI/Clicks + 7.5% HS, 1mM Zoledronic acid, and 200U IL-2, all over 14-21 days. Cytotoxicity was assessed by flow cytometry against two primary GBM explants and CMV+/- GBM cell lines U251 and U373. The expression of MIC A/B and UL-16 binding proteins was assessed using flow cytometry.
Vδ1+ T cells from CMV+ donors were significantly more cytotoxic to primary GBM explants than Vδ1+ cells from a CMV- donor (p=0.0021 for GBM 1042 and p= 0.0053 for GBM 1016) but did not significantly differ against CMV+ and CMV- U251 and U373 cells, although CMV infected cells significantly down-regulated ULBP-2 and −3 expression. Blocking of MIC A/B and ULBP-1, −2, and −3 decreased cytotoxicity of γδ T cells by 10-40% based on the expression of the respective antigen. ZOL/IL-2 expanded Vδ2+ T cells were cytotoxic to primary GBM and GBM lines regardless of donor CMV status. These findings suggest that Vδ1+ T cells, particularly Vδ1+ cells expanded from CMV+ donors, recognize GBM independently from Vδ2+ cells and and have a potential role in strategies involving CMV-directed cellular immunotherapy of high-grade brain tumors.
This study was supported by NIH NCI Grant # P50 CA 097247, NINDS Grant # 5R21 NS 57341 and the National Brain Tumor Society Samuel Gerson Leadership Chair.
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 1942.
Abstract 1943: A comparison of three techniques to induce efficient ex vivo T-cell expansion
Authors: Langsdorf Chris L. , Liu Jixiang , Bradford Jolene , Buller Gayle 
Published: February 2011

Abstract
The current study was undertaken to evaluate three common methods of inducing proliferation in a T lymphocyte population. In the first method cells are treated with purified monoclonal mouse anti-human CD3 antibody followed by addition of interleukin-2. The second approach involves treatment with the mitogen Concanavalin A. The third technique makes use of monoclonal mouse antibodies against human CD3 and CD28 immobilized on the surface of superparamagnetic polystyrene microspheres. Human peripheral blood mononuclear cells were isolated from fresh whole blood using a centrifuge density gradient. Cells were stained with CellTrace™ Violet, a novel cell proliferation tracing dye with a mode of action similar to carboxyfluorescein diacetate succinimidyl ester (CFSE), and resuspended in OpTmizer T-Cell Expansion Buffer (GIBCO) containing L-glutamine, penicillin and streptomycin. Stained cells were treated with one of the three stimulation techniques and incubated at 37°C and 5% CO2 for 7 days. A cell impermeant nucleic acid dye was used to evaluate the effect of each treatment on cell viability. The specific subpopulations induced to proliferate with each treatment were characterized in multicolor flow cytometry using monoclonal antibody conjugates against human CD3, CD4, and CD8. Cells treated with CD3/IL-2 or Concanavalin A showed a moderate, heterogeneous level of stimulation, with some cells undergoing 9 cell divisions, others remaining senescent, and approximately equal amounts remaining in generations 1 through 8. Microsphere-bound antibodies provided a much stronger, more uniform stimulus as evidenced by the very high proliferative index of cells. Concanavalin A treatment was mildly cytotoxic, while viability of cells treated with free or bound antibodies was similar to unstimulated cells. The strong, homogeneous stimulus provided by superparamagnetic polystyrene expansion beads is useful when massive numerical expansion of T lymphocytes is desired for subsequent research or adoptive transfer in vivo, but does not appear to be as useful when a population containing several discrete generations of cells is desired. The more moderate stimuli resulting from treatment with CD3/IL-2 or Concanavalin A result in a less efficient numerical expansion, but provide an excellent tool to evaluate the phenotype and pedigree of cells as they proliferate through several generations.
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 1943.
Abstract 1947: Identification of microRNAs that regulate DNA damage response
Authors: Wang Yemin , Taniguchi Toshiyasu 
Published: February 2011

Abstract
Mammalian cells have developed an elaborate DNA damage response system and DNA repair machinery, which play a critical role in the prevention of cancer and development of resistance to anti-cancer DNA damaging agents. Many proteins involved in DNA damage response, such as phosphorylated histone H2AX (γH2AX) and 53BP1, form nuclear foci at sites of DNA damage and facilitate DNA damage response and repair. The precise regulation of DNA damage response is crucial for cellular survival after DNA damage and its abrogation often results in genomic instability. MicroRNAs (miRNAs) are short, non-coding RNA molecules, which post-transcriptionally regulate gene expression by repressing translation and/or degrading mRNA. Some miRNAs function as oncogenes or tumor suppressors. However, the role of miRNAs in DNA damage response remains largely unknown. Here, we identified miRNAs that regulate DNA damage response, especially γH2AX/53BP1 foci formation, and modulate chemo-/radio-sensitivity of tumor cells. We developed a cell-based screening assay utilizing ionizing radiation (IR)-induced γH2AX/53BP1 foci formation in a human osteosarcoma cell line, U2OS, as a readout. The human miRNA Mimics and Inhibitors Libraries (Dharmacon), consisting of 810 miRNA mimics or inhibitors, were transfected in U2OS cells and screened with an automated high-throughput fluorescence microscope and an automatic foci counter. We found that two and five miRNA mimics reproducibly inhibited IR-induced γH2AX and 53BP1 foci formation, respectively, while none of the miRNA inhibitors inhibited their foci formation. Among these hits, we focused on miR-138, because miR-138 is reported to be deregulated in a subset of cancer and may be involved in tumorigenesis and chemosensitivity of cancer. We found that miR-138 decreased the expression of H2AX and reduced H2AX phosphorylation upon DNA damage. Consistent with a defect in DNA damage response, miR-138 sensitized U2OS cells to DNA damaging agents, such as IR and cisplatin. Importantly, the 3′UTR of H2AX contains a putative miR-138 binding site, suggesting that H2AX may be a direct target of miR-138. Taken together, we have identified some miRNAs which inhibit IR-induced foci formation of γH2AX/53BP1. In particular, miR-138 strongly reduced H2AX-mediated DNA damage response and enhanced the chemo-/radio-sensitivity of cancer cells, suggesting that miR-138 might serve as an important regulator of genome instability and a possible therapeutic target for 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 1947.
Abstract 1957: Loss of TGFβ1 alters host-microbial interactions, predisposing the colonic epithelium to inflammation
Authors: Ball Corbie , Azhar Mohamad , Gard Constance , Chen Dora , Mast Thomas , Aronow Bruce , Besselsen David , Doetschman Thomas 
Published: February 2011

Abstract
Introduction: The TGFB pathway is mutated in up to 30% of human colon cancers. Genetically Engineered Mouse Models (GEMs) with deficient TGFβ signaling model several characteristics of IBD associated human colon cancers. Introduction of Helicobacter sp. into the Tgfb1−/−Rag2−/− mouse model is necessary for the development of inflammatory lesions which progress to adenoma and carcinoma. The exact role of TGFβ1 and bacterial-associated inflammation has yet to be elucidated and offers a potential target for the prevention of colon cancer.
Methods: To determine the function of TGFβ1 on colonic bacterial composition we used GEM models, Tgfb1−/−Rag2−/− and Tgfb1+/+Rag2−/−. The cecal microflora of 10 Tgfb1−/−Rag2−/− and 10 Tgfb1+/+Rag2−/− mice were isolated and serially diluted onto brucella (BRU), bacteroides bile esculin (BBE), and laked kanomycin-vancomycin (LKV) media under anaerobic conditions. Colony forming units (CFUs) were enumerated. Individual colony types were then streaked onto trypitcase soy agar with 5% sheep blood and grown anaerobically and aerobically. The bacteria were then gram-stained and biotyped utilizing a Dade Berhing MicroScan instrument. To further examine the bacterial composition we designed primers specific to the 16s rRNA subunit of different Bacteroides species, and using the Roche LightCycler preformed quantitative Real Time-PCR (qRT-PCR) on fecal DNA.
Results: The Dade Berhing Instrument showed that Tgfb1−/−Rag2−/− mice had a 4 fold increase in bacterial load and a 28 fold increase in Bacteroides species when compared with Tgfb1+/+Rag2−/− mice. The qRT-PCR results showed an increase in Bacteroides fragilis and Bacteroides distasonis and a significant decrease in Bacteroides thetaiotaomicron in the Tgfb1−/−Rag2−/− mice. These data suggest that loss of TGFβ1 alters the colonic microflora. Previous studies illustrated the importance of bacterial nutrient sources on bacterial composition. To examine if TGFβ1 is altering nutrient availability in the colon a previous micro-array was analyzed for candidate genes associated with glycoprotein metabolism. This showed changes in fucose metabolizing enzymes with the loss of TGFβ1.
Conclusion: These findings suggest that TGFβ1 plays a role in bacterial load maintenance, possibly by altering available nutrient sources and when disrupted, can cause abnormalities in pathobionts (commensal bacterial with pathogenic potential) which could then lead to increased inflammation.
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 1957.
Abstract 1958: Signals activating mutant p53 in vivo
Authors: Suh Young-Ah , Post Sean , Elizondo Cathalina , El-Naggar Adel K. , Xiong Shunbin , Lozano Guillermina 
Published: February 2011

Abstract
The p53 protein is activated in response to stress signals and leads to cell cycle arrest and apoptosis. As thus, missense mutations in the p53 tumor suppressor are common alterations in tumors. p53 activity is tightly regulated by murine double minute 2 (Mdm2), an E3 ubiquitin ligase that targets wild type p53 for degradation. The Arf tumor suppressor also regulates p53 activity by binding Mdm2. Arf is activated by oncogenes, and the retinoblastoma (Rb) signaling pathway, connecting the p53 and Rb tumor suppressor pathways.
Mice inheriting p53 missense mutations that mimic common hot spots in human cancers present with a gain-of-function metastatic phenotype. An analysis of tumors from these mice indicated that some but not all had stable mutant p53 implying that other alterations besides mutation in p53 are responsible for stabilization and the gain-of-function nature of the mutant protein. Additionally, mutant p53 in normal tissues and in some tumors of homozygous mutant mice is unstable. However mutant p53 was detected in normal tissues in mutant mice lacking Mdm2 showing an increased tumor incidence and decreased survival as compared to p53 mutant mice. Importantly, stabilization of p53 correlated with a metastatic phenotype. Disruption of the Rb pathway via p16INK4a deletion, a common event in human tumors, also stabilized mutant p53 in vivo. These observations indicate that mutant protein is also regulated in the same way as wild-type p53.
Here, we examined the effects of DNA damage and oncogene activation on mutant p53 stability. Mice with Ras or c-Myc activation have stable mutant p53 and show a decreased survival in vivo. Surprisingly, stable mutant protein is also detected in mice treated with sub-dose of chemotherapeutic agent or low-dose of radiation implying that the factors affecting wild-type p53 are also responsible for mutant protein stability. Treated mice also showed decreased survival as compared to p53 mutant mice. Characterization of the mechanism by which the mutant p53 protein is stabilized in tumors is important to our understanding of the gain-of-function phenotype in these mice.
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 1958.
Abstract 196: UHRF1 is upregulated in prostate cancer and induces epigenetic silencing of tumor suppressor genes
Authors: Kunderfranco Paolo , Curti Laura , Babbio Federica , Pistore Christian , Magistri Marco , Chiorino Giovanna , Bonapace Ian Marc , Catapano Carlo V. , Carbone Giuseppina M. 
Published: February 2011

Abstract
Cancer of the prostate is the most common cancer and a leading cause of cancer death in Europe and North America. At the present there is a need to understand the mechanisms involved in the pathogenesis of this disease and discover alternative therapeutic targets. UHRF1 (ubiquitin-like protein containing PHD and RING domains 1), a nuclear RING finger protein, has been previously reported to acts as a dominant negative effectors of cell growth. UHRF1 is involved in epigenetic mechanisms by virtue of its interaction with DNMTs and HMTs. In this study, analysis of gene expression profiles of prostate tumors and normal prostate showed that UHRF1 is frequently over-expressed in tumors compared to normal tissues. UHRF1 expression was very low in immortalized prostate epithelial cells (LH) while it was higher in the Ras transformed counterpart LHSR cells. Furthermore, we observed low level of UHRF1 in the androgen-dependent prostate cancer cell lines LNCaP and 22Rv1, while higher levels were present in the androgen-independent cell lines PC3 and DU145. These data suggested that over-expression of UHRF1 is associated with malignant transformation and prostate cancer progression. To understand the role of UHRF1 we performed knockdown experiments with UHRF1 specific siRNA. Transient transfection in PC3 cells reduced UHRF1 mRNA and protein level. UHRF1 knock-down resulted in reversion of the transformed phenotype with significant inhibition of clonogenic growth in anchorage dependent and independent condition. Reversion of the transformed phenotype occurred concomitantly with restoration of the expression of several tumor suppressor genes relevant for prostate differentiation, proliferation and epithelial-mesenchymal transition such as CDH1 and RARB2. Moreover, chromatin immunoprecipitation showed binding of UHRF1 to these gene promoter and UHRF1 knockdown resulted in significant reduction of repressive histone marks on gene promoters. These studies suggest that deregulated UHRF1 expression results in epigenetic silencing of relevant tumor suppressor genes, contributing to prostate cancer progression. Targeting UHRF1 may result in re-expression of tumor suppressor genes and thus may be a valid strategy 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 196.
Abstract 1964: Genetic instability and mammary tumor formation in mice carrying mammary-specific disruption of Chk1
Authors: Li Yuing , Fischler Thomas , Xu Xiaoling , Wang Rui-Hong , Kim Hyun-Seok , Sengupta Kundan , Vassilopoulos Athanassios , Lahusen Tyler , Liu Qinghua , Elledge Steve , Ried Thomas , Deng Chuxia 
Published: February 2011

Abstract
Chk1 is a key element in the DNA damage response pathway that is required for maintaining genomic stability. To study the potential role of Chk1 in mammary tumorigenesis, we disrupted it using a Cre/loxP system. We showed that although Chk1 haploinsufficiency caused abnormal development of the mammary gland, it was not sufficient to induce tumorigenesis. Simultaneous deletion of one copy of p53 failed to rescue the developmental defects; however, it synergistically induced mammary tumor formation in Chk1+/-;MMTV-Cre animals with a median time to tumor latency of about 10 months. Chk1 deficiency caused a preponderance of abnormalities, including prolongation, multipolarity, misalignment, mitotic catastrophe and loss of spindle checkpoint that is accompanied by reduced expression of several cell cycle regulators, including Mad2. On the other hand, we also showed that Chk1 deficiency inhibited mammary tumor formation in mice carrying a homozygous deletion of p53, uncovering a complex relationship between Chk1 and p53. Furthermore, inhibition of Chk1 with a specific inhibitor, SB-218078, or acute deletion of Chk1 using shRNA killed mammary tumor cells effectively. These data demonstrate that Chk1 is critical for maintaining genome integrity and serves as a double-edged sword for cancer: while its inhibition kills cancer cells, it also triggers tumorigenesis when avorable mutations are accumulated for cell growth.
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 1964.
Abstract 1965: Cross-talk among the components of DNA damage response and chromatin remodeling
Authors: Ray Alo , Wang Qien , Zhu Qianzheng , Wani Gulzar , Zhao Qun , Wani Altaf A. 
Published: February 2011

Abstract
Chromatin remodeling is integral to the functionality of many DNA-templated processes, including DNA damage repair and damage induced checkpoint signaling. The coordinated response to genotoxic damage begins by recruitment of specific protein factors exhibiting a high degree of cross-talk to orchestrate individual pathway events. The common initial step, i.e., accessing DNA damage embedded within chromatin, is a key factor in determining the course of DNA damage response and efficiency of damage processing. Our recent studies have sought to understand the roles for the mammalian SWI-SNF components in nucleotide excision repair (NER) and checkpoint activation. We have knocked down Brg1, the catalytic component and SNF5, the core component, of the SWI-SNF complex, and assessed the impact of these knockdowns on NER and checkpoint activation. Our data suggest that SWI-SNF complex associates with UV damaged chromatin through its interaction with damage recognition factor XPC and helps stabilization of XPC at the damage site. Furthermore, SWI-SNF influences the access of ATM at the damage site, which promotes assembly of ATM-γH2AX-MDC1-53BP1-BRCA1 complex, and eventually influences NER. We propose that SWI-SNF complex positively modulates NER by facilitating stability and accessibility of NER and checkpoint factors at the UV damaged chromatin sites.
(This work was supported by NIH grants CA93413, ES2388 and ES12991)
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 1965.