bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 4853: Reduced expression of DRAM2/TMEM77 in tumor cells interferes with cell death
Authors: Jang Ik-Soon , Kim Soohyun , Choi Jong Soon , Park Sun-Mi , Park Junsoo 
Published: February 2011

Abstract
Although the role of autophagy in tumorigenesis remains controversial, recent reports support the notion that inhibition of autophagy promotes tumor formation. Damageregulated autophagy regulator (DRAM) has been identified as an effector molecule that is critical for p53-mediated apoptosis, and we investigated whether there might be other DRAM-like molecules linking autophagy and apoptosis. In this study, we cloned a novel DRAM-homologous protein, DRAM2, and showed that the expression of DRAM2 is down-regulated in ovarian tumors. DRAM2 is mainly localized in the lysosome, and colocalizes with DRAM. While expression of DRAM or DRAM2 individually did not induce cell death, co-expression of DRAM2 with DRAM significantly induced cell death, while the silencing of endogenous DRAM2 attenuated cell death, suggesting that DRAM2 is involved in cell death. Thus, we propose that reduced expression of DRAM2 may contribute to enhanced cell survival in tumor cells.
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 4853.
Abstract 4855: Role of HDACi-induced autophagy in malignant peripheral nerve sheath tumors (MPNST)
Authors: Torres Keila E. , Lopez Gonzalo , Liu Juehui , Pollock Raphael E. , Lev Dina 
Published: February 2011

Abstract
Malignant peripheral nerve sheath tumors (MPNSTs) are rare tumors that remain incurable mainly due to their high metastatic potential. These biologically aggressive tumors account for 3-10% of soft tissue sarcoma (STS). Roughly 50-60% of MPNSTs develop within the background of an inherited disease known as neurofibromatosis type-1 (NF1), while the rest develop sporadically. Despite aggressive combined modality therapy, the 5 year survival rates range from 35% to 50%. Thus, the understanding of MPNST resistance and development of a more efficient and targeted therapeutic approachs is essential to improve the otherwise dismal prognosis for these patients. Histone deacetylase inhibitors (HDACi) are novel compounds with efficacious in vitro and in vivo anti-tumor effects in a variety of tumor types including STS. Human MPNST cells treated with HDACi exhibit significant growth arrest. However, no apoptosis is observed but rather a dramatic induction of autophagy as assayed by multiple approaches. Whether drug-induced autophagy's role is to protect or kill the cells remains to be determined. Autophagy blockade via siRNA (Beclin 1 and Atg 5) or pharmacological manipulation with bafilomycin A1 and chloroquine significantly enhances HDACi pro-apoptotic effects. Furthermore, in vivo studies revealed that single agent HDACi or chloroquine alone had a modest effect on tumor growth, whereas combined treatment resulted in marked growth inhibition. These findings suggest that autophagy may mediate a potential protective response in MPNST and strongly support further study of combined HDACi with autophagy blockers as a novel therapeutic approach for MPNST.
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 4855.
Abstract 486: Abscopal effect of low-LET ionizing radiation on Rel protein signal transduction
Authors: Veeraraghavan Jamunarani , Kiosseva Svetlana , Madhusoodhanan Rakhesh , Natarajan Mohan , Herman Terence S. , Aravindan Natarajan 
Published: February 2011

Abstract
Ascertaining the ionizing radiation (IR)-induced bystander response and identifying its mechanistic regulation would raise a paradigm shift in our understanding of the radiobiological effects. Recent evidence from our lab and others clearly prompted that the transcriptional regulator NFκB would play a key role in induced responses in non-targeted bystander cells. In this study, for the first time, we investigated the orchestration of NFκB signaling after IR in an organ (heart) distant from the exposure field. The C57/BL6 mice either mock irradiated, exposed to single dose IR (SDR: 2 or 10Gy) or fractionated IR (FIR, 2 Gy/day for 5 days) were sacrificed 24h post-irradiation. All IR exposures were limited to the lower abdomen area (1cm diameter), while the rest of the animal was protected by a specially designed cerrobend shield. EMSA analysis was used to examine the changes in NFκB DNA binding activity in the heart. Transcriptional activation of 88 mediators associated with NFκB signaling pathway was assessed using QPCR profiling. Phosphorylation of ERK1/2 and p38 that play a key role in NFκB signal transduction were examined using immunoblotting. Induced DNA fragmentation was measured using TdT nick end labeling. IR significantly induced NFκB DNA binding activity in the heart. Further more, real-time QPCR profiling showed a significant and differential modulation in the transcriptional responses of NFκB signaling pathway molecules. To that end, of the 88 genes analyzed, 28, 51 and 41 genes were upregulated after 2Gy, 10Gy and FIR, respectively. More importantly, at these exposures13 out of 28, 27 out of 51 and 25 out of 41 induced mediators of NFkB pathway were significantly upregulated. Conversely, lower abdominal IR exposure markedly suppressed 44, 20 and 30 genes after 2 Gy, 10Gy and FIR, respectively in the heart of the exposed animals. Compared to 2Gy, FIR significantly induced 26 genes, while 10Gy upregulated 27 genes. In addition, 6 and 15 genes were significantly upregulated after acute dose of 2 and 10Gy as opposed to fractionated dose. Consistently, immunoblotting analysis revealed a profound phosphorylation of both ERK1/2 and p38 in the heart. Interestingly, distant IR exposure significantly enhanced DNA fragmentation in the heart tissue. Taken together, these data clearly indicated an induced abscopal response in mice heart after clinically relevant doses of IR exposure. More importantly, these data implies that orchestration of NFκB signal transduction may play a key role in induced abscopal responses.
Funding Support: Presbyterian Health Foundation, OKC.
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 486.
Abstract 4862: Histone deacetylase inhibition induces DNA damage, slows down replication forks and activates dormant origins
Authors: Leo Elisabetta , Conti Chiara , Eichler Gabriel S. , Sordet Olivier , Martin Melvina M. , Fan Angela , Aladjem Mirit I. , Pommier Yves 
Published: February 2011

Abstract
Histone acetylation is often altered in cancers and histone deacetylases inhibitors (HDACi) are actively pursued as anti-cancer agents.
SAHA (suberoylanilide hydroxamic acid) is the first HDACi approved for clinical use.
To monitor the effects of SAHA on DNA replication and genomic integrity in cancer cells, we detected broken DNA with COMET assays and analyzed phosphorylation of histone H2AX (gH2AX). Nuclear replication factories in single cells were visualized after pulse labeling with two thymidine analogs and confocal immunofluorescence microscopy. Nascent strand reverse transcriptase polymerase chain reaction (RT-PCR) in the human g-globin locus was used to assess the effects of SAHA on replication fork origin firing. In addition, cellular replicons were analyzed by genome-wide molecular combing. Our experiments prove that pharmacological concentrations of SAHA induce replication damage, as shown by single-cell and single-DNA molecule analyses. Molecular combing demonstrated a slow-down of replicons and activation of dormant replication origins in response to SAHA treatment. Similar results were obtained with siRNA-mediated HDAC3 depletion indicating the selectivity of the effect of SAHA. Activation of dormant origins at the g-globin locus control region was confirmed by nascent strand RT-PCR. Our findings demonstrate specific replication alterations and DNA damage in response to SAHA and emphasize the importance of chromatin acetylation for DNA replication in human 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 4862.
Abstract 4863: The histone lysine-methyltransferase NSD1 and its functional role in non-small cell lung cancer (NSCLC)
Authors: Joseph Roy , Stunkel Walter , Phong Mark , Fong Siew Chinn , Li Lei , Campbell Robert M. 
Published: February 2011

Abstract
NSD-1 (Nuclear receptor-binding SET domain protein 1) belongs to the epigenetic family of histone methyltransferases (HMTs), which are frequently found to be mutated in overgrowth syndromes. In cancer, NSD-1 is found as part of fusion proteins (e.g., NUP98-NSD1), which play a major role in the etiology of AML. In contrast to data from hematological tumors, little is known regarding the role of NSD-1 in cancers from solid origin, except that high level expression of NSD-1 has been correlated with poor survival in breast cancer patients (Miller, 2005). NSD-1 over-expression as well as copy number gain for the NSD-1 gene has been described in a variety of tumor cell lines. We studied the role of NSD-1 in the NSCLC line NCI-H460 using an inducible knockdown system (pSLIK). We found that knockdown of NSD-1 (&gt;70% reduction in target mRNA expression) led to a significant decrease in cell proliferation as well as nearly 100% inhibition of anchorage-independent growth, whereas an empty vector transfected stable cell line did not. NSD-1 knockdown induced apoptosis in a time-dependent manner as measured by flow cytometry-based Annexin V staining. Cell death was found to follow a PARP-dependent mechanism suggesting that apoptosis is a contributor to growth inhibition/cell death. By conducting immuno-blot experiments against a panel of histone modifications, we examined putative in vivo histone substrates of NSD1. Our data suggest that NSD1 knockdown in NCI-H460 cells leads to a decrease in histone H4K20 trimethylation (64% inhibition after 24h), but did not affect H3K36 trimethylation as previously reported for NSD1 fusion proteins in AML. Further studies of changes in additional histone modifications are ongoing. In summary, we describe for the first time a functional role for NSD-1 in a NSCLC cell line with implications for this HMT in solid tumor growth/survival.
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 4863.
Abstract 4866: The dynamic interaction of nuclear Smads with peri- and centromeric heterochromatin is involved in the modulation of histone modification and chromatin structure
Authors: Kim Tae-aug , Kim Jonghyun , Kim Saejung , Whang John , Misako Sato , Wakefield Lalage , Vladimir Larionov , Kim Seong-Jin , Niederhuber John 
Published: February 2011

Abstract
Smads are intracellular signaling transducers of TGF-β family ligands. Through TGF-β activation, phosphorylated R-Smads (Smad2/3) form active heteromeric complexes with co-Smad (Smad4) and translocate to the nucleus where they interact with chromatin to assemble the transcriptional machinery of various target genes. Evidence also indicates that Smads are involved in chromatin modulation via interactions with histone modifiers. The role of pre-existing nuclear Smads in chromatin modulation, however, has not been described, nor have the molecular mechanisms of their dynamic interaction with heterochromatin been elucidated. Here we report that nuclear Smads directly bind to specific sites on heterochromatin, altering chromatin architecture upon TGF-β activation. Subcellular fractionation indicates that both active and inactive nuclear Smad 2/3 remains in the biochemically insoluble fraction. We found that only non-phosphorylated Smad3 interacted with HP1α, a key component of heterochromatin under transcriptionally inactive conditions. The level of HP1α, but not HP1β and γ, was regulated in a TGF-β dependent manner in both Smad 2/3 KO MEFs and mouse mammary epithelial cells. Localization of the Smad3 in the pericentromeric heterochromatin and centromere regions of the human chromosomes suggests Smad3 may function as an organizer of chromatin architecture and chromosome assembly during mitosis. ChIP assay indicated that pericentromeric and centromeric heterochromatin bound Smads were dissociated by TGF-β activation and translocated to target gene promoter regions to activate gene transcription. Interestingly, TGF-β enhanced pericentromeric heterochromatin binding of Smad3 in a Smad3 overexpressed human breast cancer cell line, MCF10Ca1, but dramatically decreased in a cell line with deletion of MH2 domain in Smad3. Furthermore, deletion of MH2 domain markedly increased by more than 100 folds both H3 lys4 dimethylation and lys9 dimethylation in centromeric heterochromatin but diminished them in pericentromeric heterochromatin. This suggests that the MH2 domain of the Smad3 may play a critical role on modulation of heterochromatin structure in a manner that activates or represses genome wide gene transcription activity. In conclusion, these results indicate that nuclear Smads are involved in the modulation of chromatin structure through the regulation of HP1α and their direct interaction with peri- and centromeric heterochromatin. Therefore dysregulation of nuclear Smad expression may increase genomic instability.
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 4866.
Abstract 4867: High-throughput LanthaScreen® cellular assays for interrogating post-translational modifications of p53 and histones
Authors: Robers Matt , Machleidt Thomas , Hermanson Spencer , Wilkinson Jennifer , Wetter Justin , Bi Kun 
Published: February 2011

Abstract
Post-translational modifications such as phosphorylation, acetylation and ubquitination play important roles in regulating the structure and functions of histones and transcription factors such as p53, which in turn regulate essential gene expression. Dysregulation of these post-translational modifications has been linked to cancer and metabolic diseases. In particular, histone deacetylases (HDACs) have been pursued as valuable targets for various therapeutic interventions. However, detection of these enzymatic activities in a cell-based format has remained intractable using HTS-compatible technologies. To enable the drug discovery for these post-translational modification enzymes, we have developed and validated high-throughput compatible LanthaScreen® cellular assays for the analysis of histone and/or p53-specific acetylation, ubquitination and phoshorylation in cell backgrounds of interest. The cell cycle-dependent acetylation of histone H3 at Lys9 and the phosphorylation of histone H3 at Ser10 can be detected with terbium-labeled anti-Histone H3 acetyl-lys 9 and anti-phospho-Ser10 specific antibodies, respectively. In addition, poly-ubiquitination of Histone H2B can be measured with terbium-labeled anti-poly-ubiquitin antibody. We have also applied this technology and developed cellular assays for measuring DNA-damage induced phosphorylation at Ser15 and acetylation at Lys382 of p53. These assays were further validated with both small molecule inhibitor and siRNA against specific HDAC family members. Our results suggest that the deacetylation of Histone H3 Lys 9 is mediated by type I/II HDACs, whereas the deacetylation of p53 at Lys382 is mediated synergistically by both SIRT1 and type I/II HDAC activities. Together, these assays enable interrogation of multiple enzymatic activities responsible for post-translational modifications of challenging targets such as histones and 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 4867.
Abstract 4868: Interaction between DNMT3B and polycomb repression complexes and their role in histone modification
Authors: Li Yajun , Van Emburgh Beth O. , Jin Bilian , Robertson Keith D. 
Published: February 2011

Abstract
Epigenetic modifications, such as DNA methylation and the histone code, play crucial roles in regulating gene expression during development. Aberrant DNA methylation patterns, characterized by global genomic hypomethylation and gene specific hypermethylation at CpG islands, are found in all cancer cells and contribute directly to tumor development. DNA methyltransferases are responsible for the de novo or heritable maintenance of DNA methylation. DNMT3A and DNMT3B de novo methyltransferases contribute largely to the methylation of retrotransposon sequences and satellite repeats in pericentromeric regions. It is still unclear how gene-specific epigenetic modification patterns are established and maintained in cancer cells. Recently, high-throughput studies reported an overlapping distribution of polycomb repression complexes regulating histone modifications and DNA methyltransferase mediated DNA methylation, suggesting that there are interactions among these epigenetic regulators. Our previous data from DNA methyltransferase knock out cell lines revealed that epigenetic modifiers and the histone code influence the propensity of a gene to become hypermethylated in cancer and that DNMT3B plays an important role in regulating PRC1 function. To gain insight into the mechanisms of how DNMT3B/DNA methylation effects the histone code, and vice versa, we studied the protein-protein interactions between PRC1 components and DNA methyltransferase 3B and their functional consequences. We expressed DNMT3B and each PRC component in both baculovirus and E. coli expression systems. Pull down assays showed that there were multiple interactions between PRC1 components (eg. CBX4 /hPc2) and DNMT3B. Protein-protein interaction domains were further mapped. We then used an in vitro ubiquitination system to study the role of DNMT3B in histone H2A ubiquitination and also studied the effects of these interactions on gene expression in human tumor cell lines. Our results suggest that the interplay between DNMT3B/DNA methylation and PRC1 is important for the function of each protein/complex and that aberrations in these interactions contribute to epigenetic dysregulation in cancer cells. (Supported by NCI grant R01CA114229)
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 4868.
Abstract 4878: Bioactive dietary supplements reactivate ER expression in ER-negative breast cancer cells by epigenetic mechanisms involving active chromatin modification
Authors: Meeran Syed M. , Li Yuanyuan , Ahmed Amiya , Tollefsbol Trygve O. 
Published: February 2011

Abstract
Breast cancer is the second leading cause of cancer-related death among women in the United States. One of the important classifications of breast tumors is based on the presence or absence of the estrogen receptor (ER). While the majority of breast cancers are ER-positive, approximately 30% are ER-negative. Patients with ER-positive breast cancer receive hormonal therapy using either tamoxifen or aromatase inhibitors, and have a better prognosis. However, treatment of patients with ER-negative tumor is challenging due to the poor response to hormonal therapies in the absence ER expression. Many studies have demonstrated the chemopreventive properties of green tea polyphenols (GTPs) and sulforaphane (SFN) through inhibition of DNA methyltransferase (DNMT) and histone deacetylase (HDAC) activity, respectively. In the present study, we have observed that GTPs and SFN dose-dependently inhibit the cellular proliferation in both ER-positive and ER-negative human breast carcinoma MCF-7 and MDA-MB-231 cells, respectively. Treatment of ER-negative breast cancer cells with GTPs and SFN alone or in combination leads to the reactivation of ER mRNA expression. The combination of 20 µg/mL GTPs and 5 µM SFN was found to be the optimal dose of ER reactivation at 3 days in MDA-MB-231 cells. The reactivation of ER expression was consistently correlated with ER promoter hypomethylation and hyperacetylation. Chromatin immunoprecipitation (ChIP) analysis of the ER promoter revealed that GTPs and SFN decreased the level of dimethyl H3K9, but increased the acetylation by increasing the level of acetyl H3, acetyl H4 and acetyl H3K9. In addition, a combination of GTPs and SFN significantly inhibited DNMT and HDAC activity, which might have an important role in the reactivation of ER expression in MDA-MB-231 cells. The combination of GTPs- and SFN-mediated inhibition of DNMT activity and increase of acetylation underscores the importance of DNMTs and HDACs in maintaining the repressive environment at target genes such as ER. In addition, treatment with tamoxifen in combination with GTPs and SFN significantly increased both cell death and inhibition of cellular proliferation in MDA-MB-231 cells in comparison to treatment with tamoxifen alone. Collectively, our findings suggest that HDAC inhibitors combined with demethylating agents are a promising strategy for the epigenetic reactivation of ER expression for the effective treatment of ER-negative breast cancer.
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 4878.