bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract LB-186: Somatic Y641 mutations in EZH2 alter the balance of di- and tri-methylation of H3K27 in diffuse large B-cell lymphomas
Authors: Diaz Elsie , McCabe Michael T. , Jiang Yong , Chen Stephanie , Pappalardi Melissa , Smitheman Kimberly , Della Pietra Anthony , Graves Alan , Kruger Ryan , Brandt Martin , Sweitzer Sharon , Schwartz Benjamin , Tummino Peter J. , Creasy Caretha L. 
Published: August 2014

Abstract
EZH2 is the catalytic subunit of the Polycomb Repressive Complex 2 (PRC2) responsible for methylating histone H3 on lysine 27 (H3K27) and repressing transcription of target genes. PRC2 activity is essential for maintaining the self-renewal capacity of embryonic and adult stem cells and the dynamic regulation of this activity is critical for proper development and differentiation. Dysregulation of H3K27 methylation is implicated in tumorigenesis and occurs through multiple mechanisms. Elevated levels of EZH2 are known to correlate with poor prognosis in a number of solid tumors including prostate and breast. Inactivating mutations in UTX, an H3K27 demethylase which acts in opposition to EZH2, have been described in several tumor types including multiple myeloma, esophageal squamous cell carcinoma, and renal cell carcinoma. More recently, somatic mutations in EZH2 were identified in myelodysplastic syndrome (MDS), follicular lymphoma (FL), and GCB diffuse large B cell lymphoma (DLBCL). While the mutations in MDS are often homozygous and encompass missense, nonsense, and frame shift mutations at multiple regions of the protein, the mutations in DLBCL and FL are heterozygous and occur at a single residue (Y641) suggesting that the effect of these mutations on PRC2 activity could be quite different between MDS and lymphoma. Utilizing a biochemical approach with recombinant PRC2 containing either wild-type or mutant EZH2, we demonstrate that Y641 mutants exhibit an altered substrate preference. In contrast to wild-type EZH2 which prefers an unmodified or mono-methylated K27 residue, Y641 mutants act primarily on a di-methylated H3K27 with little activity for unmodified or mono-methylated K27. Consistent with these biochemical data, we find that when compared to wild-type lymphoma cell lines those harboring Y641 mutations have elevated levels of H3K27me3 and reduced H3K27me2. To further characterize the substrate specificity of PRC2 complexes containing either WT or mutant EZH2, we utilized an epigenetic peptide library which contained unmodified and modified peptides from histone H2A, H2B, H3 and H4. In addition, we have conducted cell-based studies to understand the effect of these mutations on H3 methylation and the regulation of EZH2 target genes. These data and the implications of these findings for the treatment of FL and DLBCL will be discussed.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-186. doi:10.1158/1538-7445.AM2011-LB-186
Abstract LB-189: Fbxo7 functions in the proliferation and maturation of hematopoietic cells
Authors: Randle Suzanne J. , Meziane El Kahina , Lomonosov Mikhail , Laman Heike 
Published: August 2014

Abstract
The F-box protein Fbxo7 specifically enhances the levels of cyclin D-Cdk6 complexes, the predominant G1 kinase active in hematopoietic cells, which is a commonly activated oncogenic pathway in lymphoid neoplasms. In addition, Fbxo7 is itself abundantly expressed in high-grade B and T cell malignancies. Previously we have tested the ability of Fbxo7 to act as an oncogene in the hematopoietic compartment in adoptive transfer experiments using p53 null hematopoietic stem cells over expressing Fbxo7. Animals reconstituted with these cells develop T cell lymphoma, supporting the idea that Fbxo7 can have tumor promoting activity in vivo. However, in experiments presented here, to investigate the transforming capacity of Fbxo7 in B lymphocytes, we found that overexpression of Fbxo7 in the mouse pro-B cell line Ba/F3 did not transform cells nor enhance their proliferation. Instead, the stable reduction of Fbxo7 expression increased proliferation and decreased cell size, which were attributable to shortening of G1 phase, decreased p27 levels and increased Cdk2 activity. These results suggest that Fbxo7 normally restrains proliferation in pro-B cells. Reducing Fbxo7 expression also changed the cell surface marker phenotype to resemble a more immature state of B cell maturation. To investigate the activities of Fbxo7 in hematopoietic cells in a more physiological setting, we have generated an in vivo model of reduced Fbxo7 expression by engineering a mouse with an insertional mutation of the LacZ gene into the FBXO7 locus. Phenotypic characterization of these mice will also be presented, and these data support the idea that Fbxo7 regulates the proliferation and the maturation of different precursor cell populations, including pro-B cells and pro-erythroblasts. We propose that Fbxo7 has the capacity to function as a tumor suppressor and also as an oncogene depending on the cell type and its stage of differentiation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-189. doi:10.1158/1538-7445.AM2011-LB-189
Abstract LB-193: APOBEC3 catalyzed genomic mutations in breast cancer
Authors: Burns Michael B. , Lackey Lela , Land Allison , Rathore Anurag , Refsland Eric , Harris Reuben 
Published: August 2014

Abstract
In this work, we present evidence that an endogenous DNA mutating protein, APOBEC3, is massively overexpressed in a high proportion of breast cancers and that this overexpression may be responsible for the genetic variability seen in these cancers. Multiple driver mutations are required for cancer development and recent genome-wide approaches have revealed that many cancers, including breast, harbor staggering numbers of mutations, both point mutations as well as gross chromosomal rearrangements. The molecular origins of most of these somatic aberrations remain unclear. In this work, we test the hypothesis that APOBEC3, an endogenous DNA mutator, is a causative factor driving these mutations. One clue derives from the fact that C/G-to-T/A transition mutations, both within and outside of methyl-C-p-G dinucleotide motifs, predominate in subsets of many tumor types, including breast cancer. We demonstrate that APOBEC3, a DNA cytosine deaminase, is a likely endogenous source of mutation in breast cancer. We show, using quantitative reverse transcriptase PCR (qRT-PCR), that APOBEC3 is overexpressed in a majority of commonly available breast cancer cell lines (34/44) when compared to MCF-10A and hTERT-HMEC control lines. This overexpression phenotype persists when examining primary breast tumors (24/37) using patient-matched normal tissues as controls. APOBEC3 is predominantly localized to the nuclear compartment when overexpressed, as seen using fluorescently tagged APOBEC3. Additionally, its catalytic DNA cytosine to uracil deamination activity is dramatically elevated in this compartment in multiple breast cancer cell lines, as quantified using a FRET-based DNA oligonucleotide cleavage assay. This presentation will discuss the potential impact of this potent endogenous mutagen on the breast cancer genome and the implications for tumor evolution and therapy resistance.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-193. doi:10.1158/1538-7445.AM2011-LB-193
Abstract LB-28: RAF inhibitors activate MAPK pathway through relief of RAF auto-inhibition
Authors: Holderfield Matthew , Merritt Hanne , Chan John , Wallroth Marco , Tandeske Laura , Hardy Steve , Hekmat-Nejad Mohammad , McCormick Frank , Nagel Tobi 
Published: August 2014

Abstract
Mutations in the RAS/RAF/MEK/ERK pathway are among the most common in human cancers, and RAF small molecule kinase inhibitors are now being tested for the treatment of BRAFV600E tumors, with promising initial results. However, both clinical and pre-clinical data indicate that selective RAF inhibitors have poor efficacy in wildtype BRAF tumors. Moreover, these inhibitors actually promote phosphorylation of downstream targets, MEK and ERK when wildtype RAF is activated by upstream components of the pathway. Here, we show that biochemical activation of wildtype BRAF and CRAF by selective RAF inhibitors is exquisitely sensitive to ATP concentrations in an in vitro kinase assay. While BRAFV600E kinase activity remains high at ATP concentrations in excess of 1mM, wildtype BRAF and CRAF reach maximum kinase velocity at ∼1–10 mM ATP and are inhibited by more than 80% in the presence of 1mM ATP. Selective small molecule RAF inhibitors block the ATP concentration dependent inhibition of wildtype RAF, demonstrating that inhibition requires RAF kinase activity and suggests RAF auto-phosphorylation. Furthermore, while in its auto-inhibited state, wildtype RAF kinase activity cannot be increased by RAF inhibitors, but is rather decreased in a dose dependent manner consistent with ATP competitive inhibition kinetics, demonstrating that binding compound does not reverse RAF auto-inhibition. Together, these results suggest a novel mechanism that can account for the paradoxical activation of MAPK pathway due to wildtype RAF inhibition whereby wildtype RAF exists in an auto-inhibited state at physiological conditions through auto-phosphorylation. In the presence of a RAF inhibitor wildtype RAF auto-phosphorylation and consequential auto-inhibition of RAF is therefore relieved to activate the MAPK pathway leading to enhanced proliferation. This study offers new insight into RAF biochemistry and enzyme kinetics with significant implications for drug development strategies and therapeutic use of RAF inhibitors.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-28. doi:10.1158/1538-7445.AM2011-LB-28
Abstract LB-284: The novel therapeutic monoclonal antibody VGX-100 neutralises VEGF-C and inhibits tumor growth and metastasis in subcutaneous and orthotopic models of human cancer.
Authors: Baldwin Megan E. , Tester Angus M. , Phelan David , Klupacs Robert 
Published: August 2014

Abstract
Angiogenesis and lymphangiogenesis are important processes facilitating tumor growth and metastasis. Growth factors that stimulate blood and lymphatic proliferation within tumors are therefore potential targets for anti-cancer therapies. Proof of concept of the clinical utility of anti-angiogenic drugs was first established by the FDA/EMEA-approved drug bevacizumab (Avastin®) which blocks VEGF binding to its receptors VEGFR-1 and VEGFR-2, the latter being the key receptor signaling for angiogenesis. However, patients treated with bevacizumab may be refractory or develop resistance to bevacizumab, suggesting upregulation of alternative pro-angiogenic proteins that allow tumors to bypass the inhibition of VEGF signalling. VEGF-C is a logical candidate for inducing resistance to bevacizumab via this mechanism since it is also a ligand for the angiogenic receptor VEGFR-2 and for VEGFR-3 which is upregulated on tumor-associated vascular endothelium.
VGX-100 is a highly specific, fully human monoclonal antibody for VEGF-C that blocks VEGF-C binding to both VEGFR-2 and VEGFR-3. Here we demonstrate that VGX-100 has an additive effect in combination with docetaxel and/or anti-VEGF (bevacizumab) in several tumor models, suggesting that VEGF-C may be an important mediator of the resistance to existing anti-VEGF therapies. Further, we demonstrate that in an orthotopic model of prostate cancer, that inhibition of VEGF-C alone by VGX-100 monotherapy is sufficient to inhibit tumor growth and significantly reduce the incidence of tumor metastasis to local lymph nodes. These data indicate that VGX-100 has exciting potential as a cancer therapeutic by targeting a key factor involved in angiogenesis, lymphangiogenesis and tumor metastasis and is expected to complement chemotherapy and/or other anti-angiogenic compounds in the clinic.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-284. doi:10.1158/1538-7445.AM2011-LB-284
Abstract LB-285: Blocking Dll4/Notch signaling inhibits development of chronic colitis-associated colorectal cancer in mice
Authors: Duarte Antonio , Badenes Marina , Trindade Alexandre , Liu Ren , Gill Parkash S. 
Published: August 2014

Abstract
Colorectal cancer (CRC) is one of the most frequent cancers worldwide, often developing as a complication of inflammatory bowel diseases. The Notch pathway plays a central role in intestinal homeostasia and its deregulation contributes to tumor development. Inhibition of Notch signaling through the Dll4 ligand shows anti-tumor activity against a variety of human and rodent tumors grafted in mice.
The aim of this work was to analyze Dll4 expression in both normal intestine and intestinal tumors, and determine the effect of Dll4 inhibition by using Dll4 heterozygous mice or administering a pharmacological inhibitor (soluble Dll4-Fc) in the mouse model of chemically induced colo-rectal cancer (CRC). To induce chronic colitis and CRC we combined the administration of azoxymethane, and repeated cycles of the proinflammatory dextran sodium sulfate in the drinking water, as previously described (Neufert et al. Nat Protoc 2: 1998) in either Dll4+/− mice or wild type mice treated with sDll4-Fc at a dose of 5mg/Kg/day, IP, 3x/wk from week 10 of AOM plus DSS treatment to week 14.
Dll4 expression was detected in the vascular endothelium as well as in both absorptive and secretive epithelium of the normal intestine and colorectal (CR) polyps. Both genetical (Dll4 allelic deletion, Dll4+/−) and pharmacological inhibition by the soluble extracellular domain of Dll4 (Dll4-Fc) led to significant reductions in the average number (12.5-fold in mutants, 3.7-fold in Dll4-Fc treated), average volume (1.6-fold in mutants, 2.3-fold in Dll4-Fc treated) and overall burden (15.2-fold in mutants, 6.3-fold in Dll4-Fc treated) of CR polyps, by inducing intratumoral apoptosis and disrupting proper tumor angiogenesis., leading to the formation of immature and non-functional blood vessels. Dll4 heterozygous mutants shown a 42.5% increase in tumor vascular density and a 13.9 % decrease in smooth muscle cell vascular recruitment, displaying increased vascular permeability and reduce vascular perfusion. Dll4-Fc treated mice displayed more proeminent vascular disruption, with a 127.5% increase in tumor vascular density and a 53.2% decrease in smooth muscle cell vascular recruitment, showing extensive vascular extravasation and poor perfusion of the tumor blood vessels.
In conclusion, Dll4Fc administration in chronic colitis-related CRC appears to constitute a promising therapeutical approach, capable of inhibiting the tumorigenic events as well as targeting the tumour vasculature and preventing tumor development.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-285. doi:10.1158/1538-7445.AM2011-LB-285
Abstract LB-286: Reconstitution of the human ovarian tumor-microenvironment in CD34-transplanted NOD-Scid-IL2Rγc null (NSG) mice
Authors: Walter Marc , Mookerjee Ananda , Nunez-Cruz Selene , Fang Chongyun , Facciabene Andrea , Coukos George , Scholler Nathalie , Danet-Desnoyers Gwenn 
Published: August 2014

Abstract
The use of stem cell-derived human immune system NSG mice and orthotopic tumors to recapitulate the human ovarian tumor microenvironment represents a significant improvement over existing mouse models of cancer. However, the careful phenotyping of a human ovarian tumor microenvironment in NSG mice has not been reported. We characterized the human ovarian tumor microenvironment in NSG mice reconstituted with a full human immune system using cord blood-derived CD34+ cell transplantation, and injected with human ovarian tumor cells. Our findings demonstrated human B cell and T cell infiltration in both orthotopic and subcutaneous tumors. Orthotopic tumors showed a 3 to 4-fold increase of human CD3+ cell infiltration in comparison with subcutaneous tumors or spleens from tumor bearing mice, however, the overall CD4/CD8 T cell ratio was similar in both tumor sites. Tumor-infiltrating T cells included effector memory TEM cells and Treg cells. Orthotopic tumor dissociates also contained significantly more human macrophages (TAMs) than subcutaneous tumors or spleens from tumor bearing mice. While all macrophages were found to have an M1-like phenotype, TAM subsets could be distinguished from splenic macrophages by CD40 or HLA-DR expression and TNFβ secretion. Furthermore, TAMs phenotypic differences observed in orthotopic tumors were associated with faster tumor growth kinetics and metastasis. Finally, we found that, in addition to the murine origin of the tumor stroma, a significant number of mouse neutrophils and macrophages were also present. We propose that humanized mice bearing human tumors could be a valuable tool for the preclinical evaluation of targeted therapies.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-286. doi:10.1158/1538-7445.AM2011-LB-286
Abstract LB-289: Angiogenesis and lymphangiogenesis in mucoepidermoid carcinoma of the minor salivary glands
Authors: Gleber-Netto Frederico O. , Florencio Taynara Nunes Guedes , Sousa Silvia Ferreira , Mendonça Elismauro Francisco , Gomes Carolina Cavalieri , Aguiar Maria Cassia Ferreira 
Published: August 2014

Abstract
The purpose of this study was to investigate angiogenesis and lymphangiogenesis in mucoepidermoid carcinoma (MEC) of the minor salivary glands as potential predictors of tumor behavior. Intratumoral and peritumoral neoformed (NMVD) and lymphatic microvessel density (LMVD) were evaluated by CD105 and D2–40 immunohistochemistry, respectively. D2–40, VEGF-A, and VEGF-C immunoexpression were also investigated in tumor parenchyma. Twenty-six paraffin-embedded MEC samples were included in the study. Palate (50%) and buccal mucosa (19.2%) were the main affected sites. Sixteen (61.5%) tumors were low-grade, 6 (23.1%) intermediate-grade, and 4 (15.4%) high-grade. Twenty (77%) cases were clinically T1-T2, and 6 (23%) were T3-T4. Nodal metastasis occurred in 3 (11.5%) cases and distant metastasis in 1 (3.8%). Three (11.5%) cases recurred, and 3 (11.5%) patients died from disease. NMVD mean was 19.58±13.91 (400x field) for intratumoral evaluation and 10.90±7.79 (400x field) for peritumoral evaluation. LMVD mean was 5.66±3.43 (400x field) for peritumoral evaluation and 0.54±3.43 (400x field) for intratumoral evaluation. Just 6 (23.1%) cases reveal intratumoral lymphatic vessels. Twenty-two (84,6%) cases showed D2–40 in neoplastic cells, mainly in epidermoid type. Fifteen (57.7%) cases were positive for VEGFA, and 11 (42.3%) were positive for VEGF-C. A positive association was observed between VEGF-A positivity and intratumoral NMVD (p=0.05). Cases with nodal metastasis, altogether, were related to low intratumoral NMVD, high peritumoral LMVD, D2–40 expression and absence of VEGF-A. Distant metastasis was associated with low intratumoral NMVD, high peritumoral LMVD, D2–40 positivity and absence of VEGF-A and VEGF-C expression. Recurrent cases presented low intratumoral NMVD, and absence of VEGF-A and VEGF-C expression. Low intratumoral NMVD, and D2–40 positive cells were found in all tumors of patients that died of the disease.
In conclusion, although NMVD, LMVD, D2–40, VEGF-A, and VEGF-C could not predict the prognosis of MEC, intratumoral NMVD, peritumoral LMVD, D2–40 and VEGF-A expression seems play a role in the occurrence of a worse behavior in this disease.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-289. doi:10.1158/1538-7445.AM2011-LB-289
Abstract LB-292: Role of TLR engagement in TIL-B and clinical implications for ovarian cancer
Authors: Nunez-Cruz Selene G. , Guerra Matthew , Connolly Denise , Gimotty Phyllis , Scholler Nathalie 
Published: August 2014

Abstract
Ovarian cancer is the eighth most common cancer in women and represents the most lethal gynecological cancer, where less than a third of the women survive longer than five years after diagnosis. The identification of novel therapeutic strategies is urgently needed to improve patient prognosis. Solid and hematologic malignant cells express a broad range of Toll-like receptors (TLR). Activation of TLR signaling through recognition of pathogen-associated molecular patterns leads to the transcriptional activation of genes encoding for pro-inflammatory cytokines, chemokines and co-stimulatory molecules. Solid tumor development has been associated with TLR engagement through both growth acceleration and immune escape, and epidemiological studies reported a link between TLR expression by ovarian tumor cells and chemoresistance. We previously observed a large proportion of B cells in the immune infiltrate of mouse ovarian tumors and in human ascites from ovarian cancer patients, but the role of TLR stimulation in ovarian tumor-infiltrating lymphocyte B (TIL-B) remains unclear. The objective of this study is to investigate the functional consequences of TLR expression and engagement on TIL-B in ovarian cancer. Our work has been carried in a transgenic mouse model (TgMISIIR-Tag) that spontaneously develops tumors through the expression of SV40 T antigen under the Mullerian Inhibitor Receptor type II (MISIIR) promoter. TgMISIIR-Tag tumors resemble human serous ovarian cancer, the most common type of ovarian cancer. Microarrays and flow cytometry analyzes were used to characterize the phenotype of TIL-B after CD19 magnetic sorting ex vivo or after in vitro culture. We first found that TIL-B significantly over-expressed transcripts encoding for inflammatory cytokines, growth factors, adhesion molecules and chemokines, compared to B cells from spleens and lymph nodes of healthy or tumor bearing mice. We also showed that B cells from TgMISIIR-TAg tumors and from ascites of ovarian cancer patients over-expressed TLR2, TLR4 and/or TLR9, to compare with mouse splenic or human peripheral B cells, respectively. In addition, five days co-culture of TIL-B with ovarian tumor cells and TLR4 and TLR 9 agonists further increased TLR4 and TLR9 expression, as well as the expression of CD5 and CD1d costimulatory molecules and IL10 production. Concomitant treatment with TLR antagonists reduced TLR expression and IL-10 production of TIL-B. In vivo studies aiming to interrogate the role of TLR engagement on TIL-B in ovarian cancer are ongoing.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-292. doi:10.1158/1538-7445.AM2011-LB-292