bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract LB-231: p 190RhoGAP-B is required for rho down-regulation and ductal morphogenesis of breast epithelial cells in compliant collagen gels
Authors: Suzanne Ponik , Wozniak Michele , Keely Patricia J. 
Published: February 2011

Abstract
Breast epithelial cells cultured in compliant (floating), but not stiff (attached), 3-dimensional collagen gels differentiate into tubules. While the mechanisms of breast ductal morphogenesis are not well understood, we have previously shown that this process requires down-regulation of the small GTPase Rho in compliant collagen gels. In this study we sought to better define the signaling pathways regulating Rho activity when epithelial cells are cultured in compliant vs. stiff 3D collagen gels. Of the known Rho regulators, expression of p190RhoGAP has been detected at the terminal end buds in the mouse mammary gland, suggesting that proper breast development in vivo requires Rho down-regulation through this protein. Therefore, we specifically investigated the role of p190RhoGAP in ductal morphogenesis. We found that shRNA against p190RhoGAP-B, but not p190RhoGAP-A, blocked down-regulation of Rho activity and inhibited tubule formation in T47D cells cultured in compliant 3D collagen gels. Additionally, both Rho and p190RhoGAP-B co-localized with the adherens junction protein, p120-catenin at sites of cell-cell adhesion when cultured in 3D collagen gels. Similar to our results with p190B knockdown, shRNA against p120-catenin resulted in disruption of ductal morphogenesis and disregulation of Rho activity in cells cultured in compliant 3D collagen gels. Interestingly, we found that the association between p190RhoGAP-B and p120-catenin, which has been shown by others to play a role in Rho regulation, increases in compliant vs. stiff collagen gels. Interaction between p190RhoGAP-B is not mediated by Rho, as it does not require the Rho binding domain of p120-catenin. Together these results demonstrate that p190RhoGAP-B is required for Rho regulation and ductal morphogenesis of breast epithelial cells in floating collagen gels through a mechanism that may involve p 120-catenin.
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 LB-231.
Abstract LB-232: MEK2 signaling pathway alone is sufficient but not necessary for melanoma cell proliferation
Authors: Lee Chih-Shia , Dykema Karl J. , Hawkins Danielle M. , Furge Kyle A. , Duesbery Nicholas S. 
Published: February 2011

Abstract
The Raf-MEK-ERK signaling pathway plays a critical role in survival of many types of cancers, including melanoma. Targeting this pathway by using MEK inhibitors is a rational therapeutic strategy for melanoma treatment. Despite their success in pre-clinical studies, MEK inhibitors have failed to obtain satisfactory responses in clinical cancer trials. An improved understanding of MEK signaling in melanoma survival will facilitate the design of more effective therapeutics. There are two isoforms of MEK; MEK1 and MEK2. Although they are thought to be functionally redundant, recent studies have suggested that these two signaling molecules have non-overlapping cellular functions. To test this we developed a novel experimental system to allow signaling through individual MEK pathway in human melanoma SK-MEL-28 cells. In this system, multiple MEK/MKK pathways are inhibited by anthrax lethal toxin (LeTx), a Bacillus anthracis-secreted toxin which specifically and proteolytically inhibits members of MEK/MKK proteins. MEK1 or MEK2 signaling is rescued by expressing a cleavage-resistant MEK mutant (MEK1cr or MEK2cr) able to actively signal in the presence of LeTx. Using this approach, we determined that MEK2 signaling, and not MEK1, is sufficient for melanoma cell proliferation and anchorage-independent growth. To explain this we hypothesized that MEK1 and MEK2 signaling differentially regulate downstream effectors to control cell survival. To test this and to identify the non-overlapping effectors downstream to MEK1 and MEK2, we compared gene expression profiles using Agilent 60-mer Whole Human Genome Microarrays. We found that global suppression of MKK signaling by LeTx treatment significantly altered expression of 20% of represented genes. These mainly include genes involved in survival pathways such as the pathways of DNA replication, E2F transcription factors, rRNA processing, and cell proliferation, as well as oncogenic pathways such as Myc and Ras. Of these genes, approximately half were rescued by expression of one of MEK1cr or MEK2cr. Whereas MEK2cr had a more pronounced effect on expression and predominantly rescued signaling associated with cell proliferation, MEK1cr rescued signaling normally associated with epithelial to mesenchymal transition. Our findings demonstrate that MEK1 and MEK2 have non-redundant cellular functions and differentially regulate downstream effectors in SK-MEL-28 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 LB-232.
Abstract LB-235: SUMO-1 modification represses CPAP transcriptional co-activator activity in TNFα-induced NF-κB signaling pathway
Authors: Yang Shu-Ting , Hung Liang-Yi 
Published: February 2011

Abstract
The transcription factor nuclear factor-κB (NF-κB) is an important regulator in inflammation, immune responses, apoptosis, cell proliferation and differentiation. CPAP (Centrosomal protein P4.1-associated protein), which plays important roles on centrosomal functions, is previously identified as the transcriptional coactivator for NF-κB. Here, we have demonstrated that decreased expression of CPAP by siRNA can attenuate NF-κB-mediated genes expression under TNFα stimulus. On the contrary, overexpressed CPAP contributes to the NF-κB-driven transcriptional activation. Immunoflourescence data showed that the nuclear localization of CPAP is induced by TNFα stimulus. Chromatin immunoprecipitation assay further indicated that CPAP was recruited to COX-2 promoter region under TNF treatment. We found that the NF-κB signaling pathway is activated by CPAP through recruiting more IKKß to the inactivated NF-κB complex to enhance the degradation of IκB and the phosphorylation of p65. Importantly, CPAP was covalently modified by small ubiquitin-related modifier-1 (SUMO-1) protein under TNFα stimulus, and the specific acceptor sites were located in the C-terminal of CPAP. Interestingly, when overexpressing SUMO-deficient CPAP in A549 cells, the TNFα-induced NF-κB-mediated genes expression was up-regulated. Co-immunoprecipitation assay showed that the association of IKKß to NF-κB complex was augmented by SUMO-deficient CPAP than wild type CPAP. Taken together, these results suggest that there might be a mechanism for the SUMOylation of CPAP in modulating the activity of NF-κB. The detailed machinery for SUMOylated CPAP in the TNFα-induced NF-κB activation is currently under investigation.
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 LB-235.
Abstract LB-243: Discovery of single amino acid changes that confer constitutive activation of mTOR in human cancer
Authors: Tamanoi Fuyuhiko 
Published: February 2011

Abstract
Mammalian target of rapamycin (mTOR), a serine/threonine kinase that belongs to the PI3K related kinase family, plays critical roles in a variety of cellular processes including protein synthesis, growth, cell cycle and autophagy in response to growth factor, nutrient and energy conditions. Overactivation of the mTOR signaling is observed in a number of human cancer. Inhibitors of mTOR such as rapamycin and its derivatives are being evaluated in clinical trials. Despite these developments that point to the significance of mTOR in human cancer, no mutations in mTOR have so far been identified in human cancer. Here we report novel mTOR mutations identified in human cancer by mining human cancer genome database. Of 889 cancer samples mined, we identified 14 amino acid changes in mTOR. Characterization of the mTOR signaling after expressing some of these mutants led to the identification of two single amino acid changes (S2215Y and R2505P) that confer constitutive activation of mTOR as detected by the phosphorylation of S6K, 4E-BP1 and S6 under nutrient starvation conditions. The mutation directly affects mTOR complex 1 (mTORC1), as the complex isolated from cells expressing the mutant mTOR after nutrient starvation still retained the activity to phosphorylate 4E-BP1 in vitro. On the other hand, we did not observe significant effects on the activity of mTORC2. The cells expressing the mTOR mutant exhibited resistance to cell size decrease by amino acid starvation and showed increased percentage of S-phase cells. The cells expressing the activated mutant were resistance to 1-butanol treatment and partially resistant to hydrogen peroxide treatment. However, they were sensitive to rapamycin. The mutations are located within the kinase domain at positions that correspond to regions where oncogenic mutations of PI3 kinase were identified. It is interesting to point out that the mTOR S2215Y mutation was identified in large intestine adenocarcinoma together with K-rasG13D mutation, while the mTOR R2505P mutation was identified in renal cell carcinoma together with CDC25A F218I mutation, raising the possibility that the mTOR mutations may cooperate with mutations in other signaling proteins. Since “we are moving into an era in which it will be possible to obtain the complete DNA sequence of large numbers of cancer genomes” (Stratton et al., Nature 458, 719), our study points to the idea that mTOR activating mutations can be identified in a wide range of human cancer yielding valuable information on the significance of mTOR in human cancer.
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 LB-243.
Abstract LB-246: Identification of novel direct targets of miR-19a in MCF-7 breast cancer cells
Authors: Kanzaki Hirotaka , Ouchida Mamoru , Ito Sachio , Tamaru Seiji , Hanafusa Hiroko , Jitsumori Yoshimi , Oka Takashi , Shimizu Kenji 
Published: February 2011

Abstract
Background: MicroRNAs (miRNAs) are small non-cording RNAs (20-23 nucleotides) that negatively regulate gene expression at post-transcriptional level by interacting with 3′UTRs of their target mRNAs. Aberrant expression of miRNAs in cancer indicates that miRNAs play key roles in human cancers acting as either oncogenes or tumor suppressor genes depending on their targets. The miR-17-92 cluster, including miR-17-5p, -17-3p, -18a, -19a, -20a, -19b and -92-1, located on C13orf25 is well known as oncogenic miRNA, which is overexpressed in lung cancer, malignant lymphoma and breast cancer. However, few data have been collected about the targets of miRNAs, including miR-17-92 cluster, and their roles in tumorigenesis. By using a proteomic approach, we identify novel direct targets of miR-19a.
Methods and Results: MiR-17-92 expression profiling was performed in a subset of 32 of cancer cell lines by TanqMan Real-time PCR, and MCF-7 breast cancer cell line was identified as a miR-17-92 cluster overexpressed cell line. To detect candidate target proteins for miR-17-92 cluster, we transfected MCF-7 cell with antisense oligonucleotides against miR-19a, -20a and -92-1 and then performed two-dimensional protein electrophoresis (2-DE) and differential display analysis in protein extracts of MCF-7 which was knocked down of endogenous miR-17-92 by antisense oligonucleotides. Of the 1455 defined valid protein spots, 146 distinct proteins changed 1.5-fold their expression. 135 proteins were identified as candidate target proteins for miR-17-92 cluster by LC-MS/MS. To determine direct targets of miR-17-92, bioinformatics analysis, luciferase assay and western blotting analysis were performed as validation studies.
Conclusions: Our results of exhaustive analysis revealed significant differences in the proteomic profile between anti-miR-LNA treated and non-treated MCF-7 breast cancer cell line. Among these candidate target proteins of miR17-92 cluster, we identified novel direct target of miR-19a. To better evaluate the role of miR-19a and the target gene, further studies of gene function are being performed now.
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 LB-246.
Abstract LB-28: Regulation of FOXM1 by NADPH oxidases in malignant mesothelioma cells
Authors: Newick Kheng , Mossman Brooke , Hillegass Jedd , Beuschel Stacie , Shukla Arti , Arbiser Jack , Pass Harvey , Heintz Nicholas 
Published: February 2011

Abstract
Malignant mesothelioma (MM) is linked to the occupational exposure to asbestos with an estimated median survival of less than two years; effective therapy is lacking. Due to long latency periods, incidence is expected to rise in regions where asbestos use has been banned, as well as where worker protection is lacking. MM cells exhibit changes in oxidant and energy metabolism, with elevated expression of the NADPH oxidase NOX4. We hypothesize that NOX4 produces reactive oxygen species (ROS) that promote uncontrolled growth through redox-dependent signaling to core cell cycle factors such as FOXM1 and FOXO3a, transcription factors involved in responses in oxidative stress and cell cycle progression. Targeted microarrays were used to assess the expression levels of 96 genes involving redox metabolism in four human MM cell lines and one control mesothelial line (LP9) immortalized with hTERT. Gene expression profiles from MM cell lines indicate tumorigenesis commonly results in elevated expression of NOX activity and adaptation to constitutive production of ROS, including up-regulation of antioxidant enzymes and cytoprotective factors. mRNA for FOXM1, a transcription factor that regulates the G2/M transition in the cell cycle, was up-regulated in all four MM cell lines, and FOXM1 continued to be expressed in MM cells, but not LP9 cells, in the absence of growth factors. Inhibitors of NOX activity markedly reduced expression of FOXM1, which correlated with dose-dependent effects on MM cell proliferation and viability. In the HM MM cell line, thiostrepton (TS), a thiazole antibiotic that inhibits the expression of FOXM1 via an unknown mechanism, increased the rate of oxidation of DCF, hyper-activated ERK1/2, and showed dose-dependent effects on MM cell viability in vitro and MM tumor growth in Fox Chase SCID mice. N-acetyl-L-cysteine blocked activation of ERK1/2 and cell death by TS, indicating the cytotoxic effects of TS in MM cells may be dependent on induction of intolerable levels of oxidative stress. In support of this possibility, inhibitors of p38 MAPK accentuated the cytotoxic effects of TS on cell viability. Our studies indicate that altered oxidant metabolism that supports expression of cell cycle factors such as FOXM1 is a common property of MM cells, and suggest that either inhibiting or accentuating the production of ROS in MM cells may be useful therapeutic approaches in the treatment of MM.
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 LB-28.
Abstract LB-288: MPI-0486348: A novel inhibitor of nicotinamide phosphoribosyltransferase (Nampt) induces tumor regression in a preclinical model
Authors: Fleischer Tracey C. , Baichwal Vijay R. , Bradford Chad L. , Demie Lynn , Green Jeremy P. , Hess Mark A. , Lockman Jeffrey W. , McKinnon Rena , Ostanin Kirill , Papac Damon I. , Reeves Leslie F. , Terry-Lorenzo Ryan T. , Willardsen J Adam 
Published: February 2011

Abstract
Background: Nicotinamide phosphoribosyltransferase (Nampt) catalyzes the first step in the recycling of nicotinamide into NAD. Cancer cells develop dependence on Nampt due to increased energy requirements and the elevated activity of NAD consuming enzymes such as sirtuins and mono and poly(ADP-ribose) polymerases (PARPs). Identification of Nampt as the target of an orphan cytotoxic compound using chemical proteomics spawned a Nampt drug discovery program at Myriad. We have developed a potent and selective inhibitor of Nampt that inhibits the growth of cancer cells in culture and induces tumor regression in a mouse xenograft model.
Materials and Methods: In vitro Nampt activity was measured in a coupled biochemical assay based on the production of fluorescent resorufin. Viability was determined by measuring cellular ATP levels at 72 hrs following addition of compound. Nampt cellular activity was assayed by measuring levels of NAD and NAD-dependent poly (ADP)-ribosylation (PAR). Pharmacokinetic studies were conducted in female CD-1 mice. Anti-tumor activity was evaluated in an HCT116 human colon carcinoma xenograft in nu/nu mice.
Results: MPI-0486348 inhibited Nampt activity in vitro with an average IC50 value of 40 pM. Depending upon the time of compound exposure, MPI-0486348 showed TC50 values of 180 pM to 20 nM in HCT116 cells. MPI-0486348 treatment also reduced cellular NAD levels and nuclear PAR levels, with IC50 values of 170 pM and 120 pM, respectively. These cellular effects of MPI-0486348 were prevented by coadministration of nicotinic acid, demonstrating on target mechanism of action. In mouse pharmacokinetic studies, absolute oral bioavailability of 47% was determined using 40% Captisol as the vehicle at an oral dose of 10 mg/kg. The same dose in rats gave an absolute oral bioavailability of 46%. Finally, in HCT116 tumor-bearing mice, a single oral dose of MPI-0486348 (50 or 75 mg/kg) resulted in 31% and 67% regression, respectively.
Conclusions: MPI-0486348 is an orally bioavailable small molecule inhibitor of Nampt and shows promising preclinical results in a human xenograft model.
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 LB-288.
Abstract LB-293: Indirubins decrease glioma growth and invasion in vivo: A novel treatment paradigm combining antimigratory and antiangiogenic effects
Authors: Williams Shante’ P. , Nowicki Michal O. , Chiocca E. Antonio , Lawler Sean E. 
Published: February 2011

Abstract
The invasive nature of gliomas is a major obstacle to their effective treatment. We demonstrated in a recent report that lithium blocks glioma cell migration and that this involved the inhibition of glycogen synthase kinase-3 (GSK-3). Here we report that treatment of glioma cells with GSK-3 inhibitors of the indirubin family leads to a potent and specific blockade of glioma cell migration. Indirubins inhibited GSK-3 to a greater extent than lithium in glioma cells as assessed by ß-catenin TCF/LEF luciferase reporter assays and were effective at much lower concentrations than other GSK-3 inhibitors so far tested. When examined in intracranial xenograft models in nude mice, 6-bromo-indirubin acetoxime (BIA) led to a significant reduction of invasion of normal, both in terms of diffuse invasion around the tumor, and the number of tumor foci. Interestingly treatment with BIA also led to decreased tumor proliferation and significantly improved survival of tumor-bearing animals. Histological examination of tumors showed a substantial decrease in blood vessel density in tumors. Finally we showed that indirubins block motility of endothelial cells in vitro, and also cause increased production of anti-angiogenic proteins in BIA treated glioma cells. This data suggests that anti-invasive glioma therapy with indirubins, and potentially other GSK-3 inhibitors, not only inhibits invasion of tumor cells, but also blocks angiogenesis providing a novel treatment paradigm for invasive gliomas.
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 LB-293.
Abstract LB-296: Synergistic anticancer action of inhibitor of DNA methylation 5-aza-2-deocycytidine and EZH2 histone methylase inhibitor 3-deazaneplanocin A
Authors: Momparler Richard L. , Marquez Victor E. , Momparler Louise F. 
Published: February 2011

Abstract
The purpose of this study was to investigate the antineoplastic action of epigenetic therapy using 5-aza-2′-deoxycytidine (5-AZA-CdR) in combination with 3-deazaneplanocin A (DZNep). Aberrant epigenetic modifications play an important role in oncogenesis. DNA hypermethylation, which can silence tumor suppressor genes (TSGs), can be reversed by treatment with 5-AZA-CdR, a potent inhibitor of DNA methylation. Overexpression of EZH2 methyltransferase (HMT) can also contribute to neoplastic transformation by silencing differentiation genes and TSGs. Recent studies have shown that DZNep, an inhibitor of HMT, can reactivate certain TSGs and has activity as an antineoplastic agent. Inhibitors of DNA methylation and histone deacetylation are reported to produce synergistic reactivation of silent TSGs and synergistic anticancer activity. Our objective was to determine if this type of “cross-talk” also exists between inhibitors of DNA methylation and inhibitors of HMT. Our experimental approach was to treat leukemic and tumor cells with 5-AZA-CdR and/or DZNep and determine cell survival by in vitro colony assays. Treatment of human HL-60 myeloid leukemic cells for 24 h with 50 nM 5-AZA-CdR or 500 nM DZNep produced a loss of clonogenity (LC) of 50.0 ± 5.8% and 75.6 ± 4.15, respectively. 5-AZA-CdR in combination with DZNep at the same concentrations of each agent produced a LC of 99 ± 1% (n =3). The interaction between these two different types of epigenetic agents was clearly synergistic. We also performed colony assays with 5-AZA-CdR plus DZNep on human A549 lung carcinoma cells. These epigenetic agents in combination also produced a synergistic LC on these tumor cells. The epigenetic action of 5-AZA-CdR plus DZNep on malignant cells of different phenotype suggests that this type of treatment may show effectiveness in most types of cancer. Our current objective is to verify the synergistic interaction between inhibitors of DNA methylation and HMT in mouse models with cancer. We are also investigating action of these agents alone and in combination on expression of cancer-related genes in order to understand the molecular basis of the synergistic anticancer activity.
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 LB-296.