bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 2049: Preclinical profile of AMG900 in combination with HDACIs in prostate cancer
Authors: Paller Channing , Wissing Michel , Kim Eugene , Hammers Hans , Rudin Charles , Carducci Michael , Kachhap Sushant 
Published: August 2012

Abstract
Background: Histone deacetylase (HDAC) enzymes maintain the structural conformation of chromatin. Inhibition of HDACs induces G1 arrest and differentiation. Previous microarray analysis demonstrated downregulation of the aurora kinase-pathway in prostate cancer cell lines treated with HDAC-inhibitors (HDACIs) vorinostat and valproic acid (VPA). Hence we sought to combine these HDACIs with AMG900, a pan-Aurora kinase inhibitor, to assess potential additive or synergistic effects, hypothesizing that low-dose combinations will have a proapoptotic effect comparable to a higher dose of AMG900 as a single agent. Methods: We used MTS assays, clonogenic assays, beta-galactosidase staining and western blot analyses to investigate differences in proliferation and molecular markers with combinations of AMG900 and HDACIs compared to AMG900 alone. Results: In vitro treatment of a panel of prostate cancer cell lines with low-dose combinations of AMG900 with HDACIs revealed enhanced antiproliferative responses compared to single agent use. Short term MTS assays only demonstrated moderate synergism in DU-145 and LNCaP cells co-treated with VPA and synergism in PC3 cells co-treated with vorinostat, based on the Chou-Talalay-method (CalcuSyn). However, all cell lines demonstrated significant decreased long term survival when combining low-dose AMG900 (1nM) with HDACIs. In DU-145 and PC3 cells lines, the low-dose AMG900 (1nM) combinations demonstrated equivalent clonogenic survival to high dose AMG900 treatment (5nM), either alone or in combination with HDACIs. We noted morphologic changes in treated cell lines and explored senescence with beta-galactosidase staining. DU-145 and PC3 cells, when treated with a combination of AMG900 and HDACIs, demonstrated a significant increase in beta-galactosidase positive cells, suggesting cell senescence (10-20% in single agent vs 50% in low-dose combinations). We also explored the mechanisms associated with decreased clonogenic survival at low doses and found a significant increase in cleaved PARP in DU-145 cells with both combinations, and with Vorinostat in LNCaP cells, but not PC3 cells which have a baseline level of ongoing apoptosis. In addition, western blot analysis showed significant differences in ACH3, pH3 and Cyclin B1 in combination treatment compared to single agent use. Conclusions: A combination of low-dose AMG900 with HDACIs in prostate cancer cell lines demonstrates synergy and efficacy equivalent to high doses of AMG900 alone, confirming our hypothesis.
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 2049. doi:1538-7445.AM2012-2049
Abstract 2059: NADPH Oxidase 4 induced ROS regulates anoikis resistance through activation of Src and EGFR.
Authors: Kim Hyeryeong , Park Eun-Kyung , Koo Kyung Hee , Park Byung-Kiu , Kim Yong-Nyun 
Published: August 2012

Abstract
Since cancer cells must overcome the anoikis for the metastasis, anoikis resistance is an important process for tumor progression and metastasis. To identify anoikis resistance mechanism, we performed mRNA microarray analysis with attached and suspended human lung epithelial adenocarcinoma A549 cells. Our microarray data reveals that Nox4 mRNA is up-regulated in the suspended cells. We evaluated both mRNA and protein levels of Nox4 and found that Nox4 is up-regulated in both mRNA and protein levels. In addition, higher levels of ROS are detected and Src activation was enhanced in suspended cells than attached cells. Interestingly, increased level of ROS in suspended cells was decreased by ROS scavengers or Nox4 inhibitors, leading to inactivation of Src and EGFR. Furthermore, knock-down of Nox4 by si-RNA specific for Nox4 resulted in inactivation of Src and EGFR. Because Src activation is not inhibited by EGFR inhibitor, Src activation appears to be independent on EGFR. In addition, si-RNA for Nox4 transfection decreased viability of cells in suspension. These results suggest that upon cell detachment, Nox4 expression is up-regulated and thus ROS levels are increased, which are important for activation of Src and EGFR, leading to sustained cell viability in the suspended cells. Therefore, we postulate that ROS generation through the Nox4 is an important process for anoikis resistance.
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 2059. doi:1538-7445.AM2012-2059
Abstract 206: A single nucleotide polymorphism (SNP) rs35301225 (A/C/T) in pre-miR-34a alters the cell cycle regulation
Authors: Srivastava Anvesha , Ramalinga Malathi , Suy Simeng , Collins Sean P. , Kumar Deepak 
Published: August 2012

Abstract
Prostate cancer (PCa) is the most common type of cancer in men in the United States and is expected to result in ∼218,000 new cases and about 32,000 deaths in 2010. Recently, microRNA miR-34a has been associated with many cancers including prostate cancer. It has been shown that tumor suppressor p53 transcriptionally regulates the expression of microRNA- miR-34a, which confers translational inhibition and mRNA degradation of genes involved in cell cycle control and apoptosis. Several GWAS studies have reported that Single nucleotide polymorphisms (SNPs) in microRNA coding genes (both in seed and mature sequence) or their target binding sites may alter the strength of miRNA binding and deregulate target gene expression. To our interest we aimed to explore the effect of germ line polymorphism rs35301225 (A/C/T) residing in miR-34a (rs35301225) on the cell cycle progression and apoptosis. Prostate (PC3 and LnCap) and breast cancer (MDA-MB 231) cell lines were transfected with pre miRNA mimics containing A/C/T alleles (rs35301225) of miR-34a and the expression of CYCLIN D1, CDK4, CDK6 and proteins associated with cellular signaling cascades, involved in cell cycle regulation were determined by Western blotting. Luciferase assay was performed for the target evaluation. The cell proliferation and apoptosis were measured by WST-1 assay and flow cytometry respectively. The expressions of apoptosis-related proteins were detected by Western blotting in the transfected cells. Western blot analysis showed that CYCLIN D1, CDK4, CDK6 and other downstream molecules were significantly down-regulated in the presence of C allele, whereas no such reduction of expression was observed in the presence of A or T allele. Cell proliferation assay showed that different alleles of miR-34a also exert profound effect on proliferation pattern of cells. Flow cytometry analysis also showed that cells with different alleles of miR-34a may exert significant effect on cell cycle progression and apoptosis. To explore if this phenomenon was confined to prostate cancer cell lines or different alleles of mir-34a may alter cell function in general, experiments were repeated with a breast cancer cell line, MDA-MB-231. Interestingly the results obtained in breast cancer cell lines were similar to that obtained in prostate cancer cell lines. The results suggest that genetic variants residing in the mature miRNA may exert a substantial effect on their expression and function, which needs to be explored along with the biological effect of miRNAs.
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 206. doi:1538-7445.AM2012-206
Abstract 2061: Implication of NQO1 knockdown on prostate carcinogenesis
Authors: Thapa Dinesh , Kumar Addanki P. , Ghosh Rita 
Published: August 2012

Abstract
NAD(P)H-Quinone Oxidoreductase 1 (NQO1) is a key antioxidant enzyme that protects against quinone derived reactive intermediates and maintains a cellular pool of antioxidants. Recent studies from our laboratory and others have been found that the expression levels of NQO1 and several GST family genes are significantly suppressed in prostate tumors in preclinical mouse models. In this study, we investigated the role of NQO1 in prostate carcinogenesis. First, we characterized basal NQO1 expression in normal prostate cells (RWPE-1), initiated prostatic epithelium (BPH-1) and prostate cancer cells (LNCaP, C42B, PC-3 and DU145). Unlike in hormone-induced tumors in vivo, in-vitro study showed increased NQO1 expression in cancer cells compared to normal cells, and that finding was consistent with other cancer cell lines such as bladder, pancreatic and melanoma cells. Stable RNAi-mediated knockdown of NQO1 in prostate cancer cells increased cell proliferation and susceptibility to oxidant treatment. Furthermore, whole genome microarray revealed that NQO1 knockdown in LNCaP cells resulted in 1603 signature genes being deregulated. COL12A1, MCP-1/CCL2, IL-8, IL1R2 mRNA were among those that showed most highly significant increase (&gt;6 fold; p&lt;0.01)., whereas mRNA for nucleoplasmin 2, phosphotyrosine domain interacting protein PID1 and the melanoma tumor specific antigen gene family member MAGEC1 were highly significantly decreased (&gt;12 fold; p&lt;0.01). Investigations are under way to determine whether these genes are direct or indirect targets of NQO1. Thus, antioxidant NQO1 plays a significant but paradoxical role acting as a double-edged sword to regulate cellular processes. However, the mechanism by which the differential expression of these genes is regulated through NQO1 still remains to be elucidated. Blocking NQO1 may regulate ARE-related transcription factors, which in turn, possibly control antioxidant and pro-inflammatory pathways.
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 2061. doi:1538-7445.AM2012-2061
Abstract 2066: Identification of NRF2 target genes in human cells: Aldoketo reductases as a potential biomarker for NRF2 activity
Authors: Choi Bo-hyun , Jung Kyeong-Ah , Song Mingu , Kwak Mi-Kyoung 
Published: August 2012

Abstract
The transcription factor NF-E2-related factor 2 (NRF2) plays a critical role in cellular defense system by up-regulating multiple antioxidant genes. Therefore, the identification of biomarker genes reflecting NRF2 activity would be important for the prediction of high-risk populations to environmental stresses. In the current study, we have investigated human genes of which expression is highly dependent on NRF2 to establish biomarker genes for NRF2 activity. For this purpose, NRF2-specific interfering RNA was stably introduced in normal human renal epithelial cells (HK-2) and human bronchial epithelial cells (NL-20), and changes in inducible genes were determined following treatment with 4 types of NRF2 activators: thiol-reacting sulforaphane, free-radical generating tert-butylhydroquinone, Michael acceptor cinnamic aldehyde and pro-oxidant hydrogen peroxide. These treatments showed relatively common alterations in gene expression, and among these, the expression of aldoketo reductase (AKR) 1C1 was highly inducible by all of these treatments in an NRF2-depedent manner. The levels for AKRs were found to be constitutively high in renal carcinoma A498 cells, of which NRF2 activity is elevated compared to normal renal epithelial HK-2 cells. In addition, the expression of AKRs was greatly enhanced by NRF2 activator treatments in human monocytes (U937), implying the potential utility of AKRs as a peripheral NRF2 marker. In conclusion, our results indicate that the expression of AKRs is highly dependent on NRF2 in human cells; therefore AKRs can be an effective biomarker for predicting NRF2 activity in human cells.
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 2066. doi:1538-7445.AM2012-2066
Abstract 2067: Putative role of Nrf2 as a tumor suppressor through inhibition of angiogenesis
Authors: Funes Juan M. , Kaufman Rachel , Flanagan James M. , Henderson Stephen , Robson Mathew , Pedley Barbara , Moncada Salvador , Boshoff Chris 
Published: August 2012

Abstract
An increase in reactive oxygen species (ROS) is a common biochemical change in cancer cells. To investigate the mechanisms of ROS accumulation during the process of tumorigenesis we employed a well-characterized model of stepwise human mesenchymal stem cell (MSC) transformation. Transformed MSC (tMSC) became dependent upon oxidative stress, as treatment with antioxidants impaired their tumorigenic potential. The increased ROS in tMSC was a consequence of a striking global down-regulation of the cellular antioxidant machinery correlating with reduced levels of the transcription factor Nrf2, a key regulator of the cellular antioxidant response. Expression of constitutive active versions of oncogenic H-Ras, Raf and PI3K/AKT led to decreased levels of Nrf2 in non-transformed MSC. Down-regulation of Nrf2 plays a central role in the defective ROS-scavenging capacity and oncogenic potential of tMSC, since its over-expression induces antioxidants, reduces the levels of ROS and impairs in vivo tumor growth. Mechanistically we show that restoration of Nrf2 expression sensitizes transformed cells to apoptosis and reduces an angiogenic response. Elevated Nrf2, in turn, led to destabilization of HIF-1α and decreased expression of angiogenic factors such as adrenomedullin and VEGF during hypoxic conditions. Moreover, we found a significant reduction in both proliferation and sprouting of human umbilical vein endothelial cells after being cultured in hypoxic/conditioned media from tMSC over-expressing Nrf2 compared with control. Down-regulation of Nrf2 during human cell transformation is not restricted to MSC as Nrf2 expression was also down-regulated when human mammary epithelial cells (HMEC) were genetically modified and transformed with the same oncogenic elements used for MSC. We performed microarray comparison studies and observed that expression of Nrf2 was down-regulated in a panel of human tumors. Furthermore, expression of Nrf2 and its downstream gene NQO1 was enhanced in breast cancer cell lines such as MCF-7 and MDA-MB-231 when the cells were treated with U0126, an inhibitor of ERK1/2 pathway. These results suggest that down-regulation of Nrf2 expression through activation of Ras/Raf/ERK pathway is not unique to in vitro transformed MSC or HMEC, but also occurs in established human breast cancer cell lines. Overall, our results indicate that Nrf2 expression is reduced in certain human tumor cells by mechanisms that involve activation of Ras signaling, and reveal a new role for Nrf2 as a tumor suppressor through inhibition of angiogenesis.
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 2067. doi:1538-7445.AM2012-2067
Abstract 207: Casitas B-lineage lymphoma-3 is an epigenetically regulated gene whose knockdown induces mesenchymal to epithelial transition and enhances erlotinib sensitivity in lung cancer cell lines
Authors: Zhang Jing , Giri Uma , Cantu Krystha , Wang Jing , Beketaev Ilimbek , Byers Lauren , Saintigny Pierre , Heymach John V. , Lin Steven H. 
Published: August 2012

Abstract
Casitas B-lineage lymphoma (Cbl) proteins are E3 ubiquitin ligases and multifunctional adaptor proteins that are implicated in the regulation of signal transduction in various cell types and in response to different stimuli. Cbl-3 is a distinct member of this family of 3 genes that is specifically expressed in the epithelial lining of organs, particularly the bronchial airways, whose function, especially in cancer cells, is relatively unknown. Here we report that Cbl-3 expression and promoter CpG island DNA methylation differed profoundly in epithelial compared to mesenchymal-like lung cancer cells. 5-azacytidine treatment, as well as DNA methyltransferase-1 (DNMT1) KD (but not DNMT-3a or 3b) enhanced promoter demethylation and Cbl-3 gene expression. Knock down (KD) of Cbl-3 in mesenchymal-like lung cancer cell lines strongly enhanced EGFR expression and activated downstream pathways. As a result, cells that were normally resistant to erlotinib became greatly sensitized to drug treatment by Cbl-3 KD. Additionally, Cbl-3 KD inhibited cellular migration and increased cellular adhesion to the extra cellular matrix (ECM) as well as promoted cell-to-cell interaction through enhanced E-Cadherin and FAK expression. These alterations suggested a mesenchymal to epithelial transition (MET) conferred by Cbl-3 KD. Take together, this data provided new insights into Cbl-3 gene regulation and elucidated a potential role of Cbl-3 in EGFR signaling in the context of EMT in lung cancer cells.
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 207. doi:1538-7445.AM2012-207
Abstract 2072: Distinct antioxidant profiles of human prostate carcinoma cell lines and tissues: Implications for rational design of redox therapy
Authors: Chaiswing Luksana , Zhong Weixiong , Oberley Terry D. 
Published: August 2012

Abstract
Several cancer chemotherapeutic drugs and radiation mediate their effects, at least in part, by generation of reactive oxygen/nitrogen species. Therefore, the levels of antioxidants and status of cellular redox state have tremendous influence on the outcome of these therapies. We analyzed antioxidant proteins in normal prostate epithelial cells and tissues as well as prostate cancer cell lines and tissues. Highly aggressive androgen-independent prostate cancer PC3 and LNCAP-C42B cells demonstrated significantly higher levels of superoxide dismutase (SOD) 2, peroxyredoxin (Prx) 1, 2, 3, and 4, thioredoxin (Trx) 1 and 2, and thioredoxin reductase (TR) 1 and 2, relative to normal prostate epithelial PrEC cells and immortalized RWPE1 human prostate epithelial cells. Similarity, the highly aggressive human prostate cancer tissues (Gleason scores 4+4 and 4+5) demonstrated significantly higher levels of SOD1 and 2, Prx 3 and 4, Trx 1 and 2, and TR 1 and 2 relative to adjacent normal prostate tissues. In contrast, the expression levels of these antioxidant proteins were lower or were not altered in less aggressive human prostate cancer tissues (Gleason score 3+3) relative to adjacent normal prostate tissues. Utilizing Trx1 redox western as a marker of cellular redox states, we found more oxidized form of Trx1 in PC3 and LNCAP-C42B cells and human prostate cancer tissues (Gleason scores 4+4 and 4+5) despite their higher levels of Trx1 protein expression. Our data suggest that alteration in antioxidant proteins and cellular redox state may differentiate cancers from non-cancer tissues. Additionally, knowledge of redox state profiles can help to predict the response of each cancer cell type to chemotherapeutic drugs and radiation.
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 2072. doi:1538-7445.AM2012-2072
Abstract 208: The MAGE family of cancer-testis antigens are potent oncogenes
Authors: Potts P. Ryan , Doyle Jennifer M. , Hao Yi-Heng , Kleinschmidt Elizabeth 
Published: August 2012

Abstract
Introduction: Cancer-testis antigens (CTAs), including the MAGE protein family, are genes whose expression is typically restricted to the germline, but are aberrantly expressed and presented as antigens in human tumors. Therefore, CTAs constitute excellent targets for cancer immunotherapy. Surprising recent evidence suggests that the aberrant expression of MAGE CTAs in tumors is not simply an inert consequence of widespread genomic deregulation, but rather an important functional event promoting tumorigenesis. Furthermore, the expression of MAGE CTAs correlates with poor prognosis in a variety of cancer types. However, the role of MAGE CTAs as oncogenes driving tumorigenesis has been unexplored and their biochemical activity of MAGEs has been enigmatic. Aims and Methods: In this study, we investigated the function of the large MAGE protein family. First we determined the oncogenic potential of more than 20 MAGE CTAs in 3T3 transformation assays, soft agar anchorage-independent growth assays, and matrigel transwell invasion assays. We then selected several of these oncogenic MAGE CTAs for further in-depth study to identify their biochemical and cellular functions. Using a variety of in vitro and cellular assays, we identified common binding partners of more than ten MAGE proteins, solved the crystal structure of one MAGE protein, and investigated the biochemical activity of several MAGE CTAs. Results and Conclusions: We found that the majority of MAGE CTAs (more than 15) have oncogenic activity in cell transformation, anchorage-independent growth, and/or invasion. Additionally, we showed that a common feature of MAGE proteins is their ability to bind to and enhance the activity of E3 RING ubiquitin ligases, such TRIM28/KAP1, through a conserved tandem winged-helix domain. Importantly, we discovered that several MAGE-TRIM28 ubiquitin ligase complexes directly ubiquitylate and degrade the critical p53 tumor suppressor in vitro and in cancer cells. Thus, our findings clearly establish that MAGE CTAs function as oncogenes through their ability to regulate the activity of E3 RING ubiquitin ligases, resulting in the deregulation of vulnerable signaling pathways (such as the p53 tumor suppressor). These results underscore the importance of MAGE proteins as therapeutic targets for cancer and highlight a novel germline signaling program co-opted by cancer cells to facilitate tumorigenesis.
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 208. doi:1538-7445.AM2012-208