bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2031: Effect of 2-Deoxyglucose on colorectal cancer cell lines
Authors: Muley Pratik U. , Olinger Alex , Tummala Hemachand 
Published: August 2012

Abstract
Aerobic glycolysis (Warburg Effect) has long been regarded as a hallmark of many types of cancers. Colorectal cancer is known to exist in hypoxic conditions and hence, it is believed that most of the colorectal carcinoma tumors depend more on glycolysis than other tumors. A number of drugs have been developed in the past to target the up-regulated glycolytic pathway of the tumor cells, including 2-Deoxy-glucose (2DG). Being structurally similar to D-Glucose, it is utilized in the glycolytic pathway and is phosphorylated to 2DG-phosphate, which starts to accumulate in the cells. The accumulated 2DG-phosphate, inhibits key glycolysis enzymes - hexokinase and phospho-glucoisomerase leading to inhibition of glycolysis, and thus starving the cells of ATP. Although this has been regarded as the major mechanism of 2DG, various observations question this being the sole mechanism of action. To further investigate the molecular mechanism of 2DG, we studied its effect on colorectal carcinoma cell lines (GC3/Cl, SW620 and SW480) alone or in combination with 5-fluorouracil (5FU). We have observed that colorectal carcinoma cells are highly susceptible to 2DG compared to other cancer cells or non-cancerous cells and exert an additive effect in combination with 5FU. 2DG treatment arrested cell cycle at G1/G0 checkpoint and promoted apoptosis. The treatment of 2DG also resulted in a transient increase in the expression of p21. A reduced expression of other cell cycle proteins such as cyclin D1 and cyclin A was also observed following the 2DG treatment. Here, we provide evidence that in colorectal carcinoma cell lines, the 2DG causes a cell cycle arrest in addition to glycolysis inhibition and this additional activity may be responsible for an increased susceptibility of colorectal cancer cell lines to 2DG.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2031. doi:1538-7445.AM2012-2031
Abstract 2035: The effect of KLF5 on cell cycle progression depends upon p53 status
Authors: Yang Yizeng , Lai Dongming , Tetreault Marie-Pier , Katz Jonathan P 
Published: August 2012

Abstract
Background: p53 mutation is one of the most common genetic events in esophageal squamous cell cancer (ESCC), and loss of Krüppel-like factor 5 (KLF5) in the context of p53 mutation transforms primary esophageal squamous epithelial cells. Interestingly, while KLF5 promotes proliferation in non-transformed esophageal squamous epithelial cells, KLF5 is growth inhibitory in ESCC. The mechanisms of this context dependent effect of KLF5 on cell Hypothesis: We hypothesized that the effect of KLF5 on cell cycle progression is dependent on p53 status. Methods: Human primary esophageal keratinocytes with or without either wild type or mutant p53R175H were transduced with lentivirus expressing inducible KLF5 shRNA or control. We investigated cell proliferation by MTT assay and cell cycle progression by flow cytometry. The expression of the cyclins and cyclin-dependent kinases were assessed by quantitave PCR. p21waf/cip1 activity was determined using a luciferase reporter. Results: In the context of wild-type p53, KLF5 suppression decreased cell proliferation and produced growth arrest at G2/M, with decreases in cyclin A2 and cyclin E1expression. In contrast, KLF5 loss in human primary keratinocytes harboring the common human p53 mutation p53R175H accelerated the cell cycle with more cells in G1/S and increased cyclin D1 expression. Interestingly, KLF5 directly bound within the p53 response elements in the regulatory region of p21waf/cip1 and activated its promoter activity only in cell with mutant p53. In addition, KLF5 suppression diminished p21waf/cip1 responsiveness to UV irradiation and growth factor depletion only in p53 mutant cells. Conclusions: Here, we identify a novel mechanism for context dependent effects of KLF5 on cell cycle via p53. These findings, in combination with the previously-established effects of KLF5 and p53 loss on cellular transformation, suggest that KLF5 is an important brake on the cell cycle and may function as a tumor suppressor in esophageal squamous cell cancer.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2035. doi:1538-7445.AM2012-2035
Abstract 2036: Forced activation of Cdk1 via Wee-1 inhibition impairs homologous recombination in breast cancer cells
Authors: Van Vugt Marcel A. , Krajewska Malgosia , Bisselink Yvette , Seinstra Renee I. , Sillje Herman H. , de Vries Elisabeth G. 
Published: August 2012

Abstract
In response to DNA breaks, the so-called ‘DNA damage response’ provokes a cell cycle arrest to facilitate DNA repair. Recent findings have indicated that cells can respond to DNA damage throughout the cell cycle, except during mitosis. Specifically, various mitotic kinases, including Cdk1, Aurora A and Plk1, were shown to inactivate key DNA damage checkpoint proteins, including 53BP1. As a consequence, aberrant expression of mitotic kinases during interphase might modulate cellular responses to DNA damage. In this study we analyzed how aberrant activation of Cdk1 affects the cellular responses to DNA damage in breast cancer cells. We used Wee1 inhibition to enforce Cdk1 activation, which did not cause cytotoxicity in non-transformed cells. In contrast, Wee1 inhibition accelerated mitotic entry and caused radio-sensitization in p53-defective, but not p53-proficient breast cancer cells. Interestingly, we could show that Wee1 inhibition leads to elevation of Cdk1 activity in interphase breast cancer cells. When we subsequently analyzed DNA damage responses in cells with forced Cdk1 activation, we observed a marked reduction of the repair protein 53BP1 at the sites of DNA damage. In addition, Wee1 inhibition resulted in an increase in the number of γ-H2AX foci after irradiation, indicative of defective DNA repair. Indeed, when DNA repair was analyzed using in vivo endonuclease-induced recombination assays, compromised DNA repair after Wee1 inhibition was confirmed. Taken together, our data show that Wee1 inhibition leads to forced Cdk1 activation in interphase cells and that this interferes with normal DNA damage responses.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2036. doi:1538-7445.AM2012-2036
Abstract 204: Molecular function of the RNA binding protein EWS in RNA processing
Authors: Nieves Bethsaida I. , Niu Shuang , Vaka Dedeepya , Salzman Julia , Brown Patrick , Sweet-Cordero Alejandro I. 
Published: August 2012

Abstract
The Ewing Sarcoma (EWS) protein is a member of the FET family of RNA-binding proteins and is involved in chromosomal translocations that generate oncogenic fusion genes found in a variety of sarcomas. EWS has been recently reported to be involved in regulating transcription, pre-mRNA processing, translation and DNA repair. However, the precise physiological role of EWS in RNA processing remains largely unknown. Using cross-linking immunopercipitation coupled with high-throughput sequencing (CLIP-Seq), we identified the full complement of RNAs bound to EWS in Hela cells. Analysis of RNA binding by EWS revealed that the greatest increase in binding was to mRNAs coding for A-I editing enzymes ADAR1, ADARB1 and ADARB2. EWS also bound to non-coding RNAs (lncRNAs) NEAT1 and MALAT1. Interestingly, these lncRNAs localize to specific subnuclear structures and have been implicated in regulating RNA editing and RNA splicing respectively. We hypothesize that EWS could play a role in regulating the subnuclear localization of other proteins involved in editing and splicing by virtue of its association with NEAT1 and MALAT1. We also found that binding of EWS to pre-mRNAs influenced alternative splicing. Paired-end RNA-Seq of the transcriptome revealed that knock down of EWS resulted in the over expression of 116 genes and the down regulation of 68 genes, including EWS itself. Further analysis identified 16 alternatively spliced genes following EWS knock down across two independent RNA seq experiments. Of these genes, 6 were also shown to bind EWS by CLIP-seq. These genes include, CENPA, CSTF1, RBBP6, RAC1, FANC1 and ANAPC5. These studies highlight a potential role for EWS as a critical regulator of alternative splicing and A-I editing.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 204. doi:1538-7445.AM2012-204
Abstract 2040: The Mre11 nuclease is critical for sensitivity of cells to Chk1 inhibition
Authors: Thompson Ruth H. , Montano Ryan E. , Eastman Alan R. 
Published: August 2012

Abstract
The Chk1 kinase is required for the arrest of cell cycle progression when DNA is damaged, thereby providing time for cells to repair their DNA and recover. Chk1 also stabilizes stalled replication forks. As a consequence, many Chk1 inhibitors have been developed and tested for their potential to enhance DNA damage-induced tumor cell killing. However, inhibition of Chk1 alone, without any additional exogenous agent, can be cytotoxic. Using the novel Chk1 inhibitor MK-8776 (previously known as SCH900776), we screened a panel of cell lines and found that some are killed rapidly at low concentrations while other cell lines continue to grow in the presence of much higher concentrations. Understanding the underlying mechanisms of this sensitivity is critical for defining which patients might respond best to therapy with Chk1 inhibitors. We have investigated the mechanism of sensitivity in U2OS osteosarcoma cells. Upon incubation with MK-8776, single-stranded DNA regions (ssDNA) and double-strand breaks (DSB) begin to appear within 6 h. These DSB have been attributed to the structure-specific DNA endonuclease, Mus81. The Mre11/Rad50/Nbs1 (MRN) complex is known to be responsible for the resection of DSB to ssDNA. However, we show that inhibition of the Mre11 nuclease activity leads to a decrease not only in the amount of ssDNA following Chk1 inhibition, but also in the formation of DSB, suggesting that DSB arise as a consequence of ssDNA formation. These findings were corroborated by the discovery that Mre11-deficient ATLD1 cells are highly resistant to MK-8776 and form neither ssDNA nor DSB following treatment, but once complimented with exogenous Mre11, the cells accumulate both ssDNA and DSB when incubated with MK-8776. Inhibition of Chk1 also leads to aberrant activation of Cdc25A and Cdk2, and our findings suggest that Mre11 provides the link between Cdk2 activation and Mus81. We propose that the variable sensitivity of cell lines to Chk1 inhibition reflects defects in this pathway. These data highlight a novel role for Mre11 in the production of DSB and may help define which tumors are more sensitive to MK-8776 alone or in combination with DNA damaging agents.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2040. doi:1538-7445.AM2012-2040
Abstract 2041: Her2/Neu has an essential role for the gamma-irradiation-induced ERK1/2 signaling activation and G2/M checkpoint response
Authors: Yan Ying , Greer Patrick M. , Kolb Ryan H. , Cowan Kenneth H. 
Published: August 2012

Abstract
Gamma-irradiation (IR)-induced double strand DNA breaks frequently results in G2/M cell cycle arrest, allowing time for DNA repair prior to re-entering cell cycle. Previous studies from our laboratory have shown that the G2/M checkpoint activation following exposure of MCF-7 breast cancer cells to IR is dependent on the activation of extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) signaling. Studies presented in this report indicate that IR exposure of several breast cancer cell lines (MCF-7, MDA-MB-231, SKBR3 and T47D) is associated with a marked increase in HER2/neu phosphorylation and that the inhibition of HER2/neu using specific inhibitors abrogates the IR-induced activation of both MEK1/2 and ERK1/2 in these cells. Furthermore, the HER2/neu inhibition also results in attenuation of IR-induced G2/M arrest and concomitant diminution of IR-induced activation of ATM, ATR, Chk1 and Chk2 kinases. In contrast, inhibition of HER1/EGFR using specific inhibitors has no detectable effect on IR-induced increase of ERK1/2 phosphorylation as well as the induction of G2/M arrest following IR exposure. Collectively, results in this report suggest that HER2/neu plays an essential role in the activation of IR-induced of MEK/ERK signaling and subsequent G2/M checkpoint response.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2041. doi:1538-7445.AM2012-2041
Abstract 2042: The RAX/PACT-PKR stress-signaling pathway promotes p53 sumoylation and stability to induce G1 arrest
Authors: Bennett Richard L. , Pan Yu , Hui Teng , May W. Stratford 
Published: August 2012

Abstract
Cellular stresses including IL-3 withdrawal from factor-dependent hematopoietic cells, inflammatory cytokine treatment or viral infection promote RAX/PACT-dependent activation of the interferon-induced, double-stranded RNA activated protein kinase PKR. Previously, we and others demonstrated that activated PKR phosphorylates the alpha subunit of eIF2 to inhibit protein synthesis and initiate apoptosis. In addition, recent reports indicate that PKR may regulate the transcription factors p53, STAT1 and NF-κB. Now we find that RAX/PACT interacts with the SUMO E2 ligase Ubc9 to stimulate p53-Ubc9 association and reversible p53 sumoylation on lysine 386. In addition, stable or transient expression of RAX/PACT in a variety of cell lines promotes p53 stability and activity to increase p53 target gene expression. Significantly, while expression of RAX/PACT, PKR or p53 alone has little effect on the cell cycle of p53-null H1299 cells, co-expression of p53 with either RAX/PACT or PKR promotes a 25 - 35% increase of cells in G1. In contrast, co-expression of RAX/PACT with the sumoylation-deficient p53 (K386R) mutant or with p53 and the desumoylase SENP1 fails to induce such a G1 arrest. Furthermore, RAX/PACT-induced, p53-dependent G1 growth arrest is inhibited by expressing the dominant-negative PKR (K296R) mutant, and expression of RAX/PACT in pkr+/+ but not pkr-/- MEF cells promotes p53 and p21 expression following gamma irradiation. Significantly, expression of exogenous RAX/PACT promotes phosphorylation of wild-type but not p53 (K386R) on serine 392, and p53 stability is decreased in cells with reduced RAX/PACT or PKR following doxorubicin treatment. Collectively, results indicate that in response to stress the RAX/PACT-PKR signaling pathway may promote p53 translational activation leading to G1 cell cycle arrest by a mechanism dependent on p53 sumoylation and phosphorylation that regulates protein turnover. Importantly, these novel findings may indicate a wider role for the RAX/PACT-PKR signaling pathway to direct sumoylation-dependent subcellular localization, protein stability or protein-protein interactions of downstream targets in response to cellular stress.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2042. doi:1538-7445.AM2012-2042
Abstract 2045: BubR1 is modified by sumoylation during mitotic progression
Authors: Yang Feikun , Hu Liyan , Yao Yixin , Yu Jianxiu , Khodjakov Alexey , Pagano Michele , Dai Wei 
Published: August 2012

Abstract
BubR1 functions as a crucial component that monitors proper chromosome congression and mitotic timing during cell division. We investigated molecular regulation of BubR1 and found that BubR1 was modified by an unknown post-translation mechanism during the cell cycle, resulting in a significant mobility shift on denaturing gels. We termed it BubR1-M as the nature of modification was not characterized. Extended (&gt;24 h) treatment of HeLa cells with a microtubule disrupting agent including nocodazole and taxol or release of mitotic shake-off cells into fresh medium induced BubR1-M. BubR1-M was derived from neither phosphorylation nor acetylation. Ectopic expression coupled with pulling down analyses showed that BubR1-M was derived from SUMO modification. Mutation analysis revealed that lysine 250 was a crucial site for sumoylation. Significantly, compared with the wild-type control, ectopic expression of a sumoylation-resistant mutant of BubR1 induced chromosomal missegregation and mitotic delay. Combined, our study identifies a new type of post-translational modification that is essential for BubR1 function during mitosis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2045. doi:1538-7445.AM2012-2045
Abstract 2056: Molecular delineation of TIP150 function underlying kinetochore microtubule dynamics during mitotic chromosome segregation
Authors: Ward Tarsha L. 
Published: August 2012

Abstract
The microtubule cytoskeleton orchestrates the cellular dynamics and plasticity that underlies cellular morphogenesis. Microtubule binding proteins known as “TIP” proteins regulate the dynamic properties of microtubules during chromosomal segregation and cellular division. Our recent study revealed that TIP150 is a novel plus end tracking protein interacting with EB1 and MCAK in vitro and in vivo (EMBO Reports. 2009. 10:857-65). However, it is unclear whether and how this interaction regulates chromosome segregation in mitosis. We hypothesize that Tip150 is essential for chromosome segregation, and governs proper kinetochore-microtubule attachment at the microtubule plus end. To delineate the molecular function of TIP150 and its regulation in chromosome segregation and the mitotic cell cycle, a combination of biophotonic analyses with RNA interference was employed. Immunofluorescence reveals that TIP150 localizes to the outer most part of the kinetochore and to the ends of growing microtubules by its C-terminal domain. Suppression of TIP150 resulted in an increase in mitotic defects, reduced kinetochore-microtubule attachment, and perturbed chromosome oscillation dynamics. Furthermore, the use of total internal reflection microscopy reveals a novel role for TIP150-EB1 elicited tracking to the microtubule ends. We reason that TIP150 is essential for kinetochore-microtubule attachment in mitosis and microtubule dynamics.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2056. doi:1538-7445.AM2012-2056
Abstract 2064: Atm is required for homeostasis within the lactating mammary gland
Authors: Dyer Lisa M. , Brown Kevin D. 
Published: August 2012

Abstract
ATM is a protein kinase activated in response to DNA damage and oxidative stress. Limited evidence suggests that ATM functions in mammary gland development and tumor suppression. However, we now document that mice with germ line loss of Atm exhibit severely blunted mammary gland development. To examine a role for Atm within the mammary gland we generated a novel mouse line with conditional deletion of Atm (AtmWAP-cre) in the mammary epithelium. Characterization of the AtmWAP-cre mouse line indicated that reduced Atm expression results in a progressive lactation defect as judged by a reduction in pup growth rate, aberrant lobulo-alveolar structure, and significantly diminished expression of several milk protein genes in mid-lactation dams. We also document that lactating AtmWAP-cre dams exhibit both morphological and molecular features consistent with premature entry into involution. These aberrant events in Atm-deficient glands occur independently of established Jak/Stat signaling mechanisms that normally control mammary gland development. We found that RNA harvested from lactating Atm-deficient mammary glands contain heightened levels of oxidized guanine (8-oxoGua) indicating unchecked response to oxidative damage. Finally, we knocked down ATM expression in human and mouse mammary epithelium-derived lines and measured increased sensitivity to oxidative stress. This study supplies evidence for a novel biological function for Atm within the mammary gland and provides new insight into the critical importance of oxidative stress response during the high metabolic burden associated with the process of lactation.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2064. doi:1538-7445.AM2012-2064