bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract C126: Molecular profiling of the HES transcription factor-TLE co-repressor protein-protein interaction site.
Authors: Roffey Jon R. , Hammonds Tim , Raynham Tony , Dillon Christian , Hyde Cali , Pearl Laurence , Ish-Horowicz David 
Published: June 2012

Abstract
Aberrant Notch signalling has been implicated in a variety of tumor types, where it is known to play a role in tumorigenisis and angiogenisis. In particular, recent evidence suggests that the Notch pathway is activated by somatic mutations in a significant proportion of human T cell acute lymphoblastic leukaemias (T-ALLs). Therefore targeting of the Notch pathway represents an attractive avenue for anti-cancer drug discovery. However, apart from the potential use of gamma-secratase inhibitors, there are very few known tractable intervention points along this predominantly protein-protein interaction mediated pathway. The structural characteristics of protein-protein contact surfaces present a huge challenge for small molecule drug discovery as these contact surfaces are generally larger than those involved in protein-small molecule interactions and often lack the grooves and pockets on the protein surface that small molecules efficiently bind to. Recent discoveries in our laboratories indicate that the interaction of the HES transcription factor with the TLE co-repressor could provide a tractable point for small molecule inhibitors that would inhibit the Notch signalling pathway. The interaction between HES/TLE is dependent on a highly conserved contiguous tetra-peptide WRPW motif present in the C-terminus of HES family members which binds to the WD domain of TLE. The binding site on TLE is a potentially druggable hydrophobic recess located at the central pore of a 7-bladed β-propeller structure, and the WRPW motif sits on top of the recess contacting all 7 blades of the -propeller. We have established and validated biochemical fluorescence polarisation (FP) and GST-WRPW pull down assays to identify compounds that disrupt HES/TLE binding in vitro and a GAL4-WRPW reporter luciferase assay was developed as an effective way of monitoring the WRPW dependent interactions between HES and TLE proteins in a cell culture model. Using these assays a small library of peptide derivatives, based around the highly conserved WRPW motif, was screened. SAR from the peptide array in conjunction with structural information from a WRPW peptide bound to TLE1 WD domain was used to construct a 3D pharmacophore model which was applied as a search query for in silico virtual screening.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C126.
Abstract C127: Crystal structure of the SIX1/EYA transcriptional complex reveals ways to inhibit SIX1-mediated breast tumorigenesis/metastasis.
Authors: Patrick Aaron , Cabrera Joshua , Zhao Rui , Ford Heide 
Published: June 2012

Abstract
The Six1 homeoprotein and members of the Eya family of co-activators are thought to form a bipartite transcription factor that is important in development and disease. Six1 and Eya are highly expressed during development, but their expression is lost in most adult tissues. Interestingly, Six1 and Eya are re-expressed in a variety of cancers, where they are known to promote both transformation and metastasis. However, a means to target the complex has remained elusive due to the recognized difficulties in targeting transcription factors. Thus, the molecular details of the protein-protein interface and an understanding of whether complex formation is necessary for tumorigenesis/metastasis are critical to the development of novel anti-cancer therapies targeting the Six1/Eya complex. Here we describe the 1.9 Å resolution crystal structure of the Six1/Eya complex revealing unexpected protein binding interfaces. The interaction resembles that of the p53/HDM2 complex, with a single helix of Six1 binding in a hydrophobic groove in Eya, both distant from sites originally thought to be involved in the Six1/Eya interaction. Remarkably, we show that a single amino acid substitution in Six1, involving a residue in the Eya binding interface, is sufficient to inhibit complex formation and to inhibit properties associated with Six1-induced tumorigenesis/metastasis. Since Six1 and Eya are regulators of embryonic development and are scarcely expressed in adult tissues, inhibition of the Six1/Eya pathway likely will lead to limited side effects in the adult. In addition, since 50–90% of breast cancer patients over-express Six1, therapies targeting the complex are likely to benefit a significant proportion of breast cancer patients, and an even greater proportion of patients with metastatic disease. Together, our findings suggest that inhibiting the Six1-Eya helical interface is a potential mechanism to develop novel, anti-breast cancer agents.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C127.
Abstract C128: Small-molecule antagonists of MDM2 and MDMX.
Authors: Thompson Thelma , Graves Bradford , Xia Mingxuan , Janson Cheryl , Lukacs Christine , Deo Dayanand , Huang Kuo-Sen , Tovar Christian , Lovey Allen , Wanner Jutta , Vassilev Lyubomir T. 
Published: June 2012

Abstract
The p53 tumor suppressor is controlled by MDM2 and MDMX that negatively modulate its activity. Both proteins possess p53-binding sites within their N-terminal domains and can inhibit the transcriptional activity of p53. However, only MDM2 can serve as E3 ubiquitin ligase for p53 and is thus responsible for its stability. MDMX does not have intrinsic ligase activity but can modulate the ligase activity of MDM2. Many human tumors overproduce MDM2 or MDMX to impair p53 function. Small-molecule MDM2 antagonists, the nutlins, interact specifically with the p53-binding pocket of MDM2 and can release p53 from negative control. Treatment of cancer cells expressing wild-type p53 with nutlins stabilizes p53 and activates the p53 pathway, leading to cell cycle arrest and apoptosis in vitro and in vivo. However, nutlins and other published MDM2 antagonists do not inhibit the p53-MDMX interaction and their effectiveness can be compromised in tumors overexpressing MDMX. We identify the first small molecules that potently block p53 interaction with both MDM2 and MDMX (in vitro IC50 of 17 nM and 24 nM, respectively) by inhibitor-driven homo- and/or hetero-dimerization of MDM2 and MDMX proteins. Structural studies revealed that these idole-hydantoin compounds bind into and occlude p53 pockets of MDM2 and/or MDMX by inducing the formation of dimeric protein complexes kept together by a dimeric small-molecule core. This novel mode of inhibiting protein-protein interactions effectively stabilized p53 and activated p53 signaling in cancer cells, leading to cell cycle arrest and apoptosis.
MDM2/MDMX antagonist, RO-5963, restored p53 apoptotic activity in cultured osteosarcoma cells in the presence of high levels of MDMX. RO-5963 showed a significantly better apoptotic activity against MCF7 and other solid tumor cell lines with higher MDMX levels than the MDM2-specific inhibitor, nutlin-3a, suggesting that dual antagonists may offer a more effective therapeutic modality for MDMX-overexpressing cancers.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C128.
Abstract C135: Therapeutic targets for MYC-driven cancer.
Authors: Toyoshima Masafumi , Howie Heather , Imakura Maki , Walsh Ryan , Park Julie , Grandori Carla 
Published: June 2012

Abstract
Drugs directed toward oncoproteins have demonstrated efficacy while avoiding the systemic toxicity associated with standard chemotherapeutics. However, oncoproteins encoding for transcription factors, such as the MYC family, which are broadly implicated in many human cancers, are difficult to inhibit with small molecules or antibody based therapies. Thus, to target MYC-driven cancers, we have taken the approach of identifying druggable genes that exhibit a synthetic lethal relationship with aberrant MYC expression. Using an isogenic cell model system, we identified, via high throughput siRNA screening, more than 100 druggable genes that exhibit a synthetic lethal interaction with MYC (referred to as MYC-synthetic lethal genes, MYC-SL). Among the MYC-SL genes, we focused on casein kinase 1 epsilon (CSNK1e), whose relevance in MYC-driven human cancer was demonstrated by correlation between high levels of CSNK1e expression, MYCN amplification, and poor clinical prognosis in neuroblastoma cases. The requirement of CSNK1e for growth of neuroblastomas with MYCN amplification was validated in vivo by conditional knock-down and via a small molecule inhibitor of its activity. CSNK1e had previously been implicated in the regulation of WNT, however our data also suggest that in neuroblastoma the activity of CSNK1e is a key component of a positive autocrine circuit triggered by MYCN amplification that sustains both WNT and SHH pathways. In summary, our work elucidates a broad network of MYC synthetic lethal genes, perhaps a reflection of its widespread effects on gene expression, and demonstrates the power of high throughput siRNA screening as a rapid and unbiased approach to identify a network of synthetic lethal genes and potential new therapeutic targets functionally linked to a previously un-druggable oncogene.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C135.
Abstract C147: Itraconazole side-chain analogs reveal a distinct structure-activity relationship for inhibition of hedgehog pathway signaling.
Authors: Aftab Blake T. , Shi Wei , Nacev Benjamin A. , Head Sarah , Liu Jun O. , Rudin Charles M. 
Published: June 2012

Abstract
Itraconazole is an antifungal drug that was recently found to potently inhibit the Hedgehog (Hh) signaling pathway. The mechanism of inhibition of Hh signaling is distinct from that of cyclopamine-competitive inhibitors currently in late-stage clinical development. Itraconazole has also been described as a potent inhibitor of activation of vascular endothelial growth factor receptor-2 (VEGFR-2) and tumor associated angiogenesis. The unexpected activities associated with this FDA-approved agent offer a unique opportunity for expansion of its use to the oncology arena. As such, itraconazole is currently being evaluated in several clinical trials targeting proliferative disease, including basal cell carcinoma and recurrent metastatic non-small cell lung cancer. To date, the target(s) of itraconazole responsible for these activities remain to be determined. In these studies we expand the characterization of the activity profile for itraconazole by examining potency in the context of a Smoothened receptor point-mutation associated with clinical resistance to vismodegib (GDC-0449). Additionally, in the interest of understanding the structure-activity relationship (SAR) guiding Hh pathway targeting and working towards the identification and development of inhibitors demonstrating greater potency and specificity; twenty-five itraconazole side chain analogs were synthesized and assayed for inhibition of Hh pathway activation. Furthermore, the SAR associated with the inhibition of phospho-activatable forms of VEGFR2 is also described. Through these analyses we report that itraconazole maintains potency against the Hh pathway in the context of the D477G Smoothened mutation (mouse homologue to human D473H). We also conclude that SAR trends for targeting of the Hh pathway are divergent from those associated with inhibition of VEGFR2 signaling. Taken together, these results suggest that modification of the sec-butyl side chain of itraconazole can enhance compound activity and differentially affects inhibition of the Hh pathway and VEGFR2 signaling.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C147.
Abstract C149: STAT3 is a critical mediator of the prosurvival effect of Bcl-2-Rac1 interaction in human cancer cells.
Authors: Kang Jia , Vali Shireen , Kapoor Shweta , Abbasi Taher , Pervaiz Shazib 
Published: June 2012

Abstract
The small GTPase Rac1 is involved in the activation of the reduced NAD phosphate oxidase complex resulting in superoxide production. We recently showed that Bcl-2 overexpression inhibited apoptosis by creating a pro-oxidant intracellular milieu, and that inhibiting intracellular superoxide production sensitized Bcl-2-overexpressing cells to apoptotic stimuli. Gene silencing and functional inhibition of Rac1 blocked Bcl-2-mediated increase in intracellular superoxide levels in tumor cells. We provide evidence for a co-localization and physical interaction between the 2 proteins, which could be blocked in vitro and in vivo by the BH3 mimetics as well as by synthetic Bcl-2 BH3 domain peptides. That this interaction is functionally relevant is supported by the ability of the Bcl-2 BH3peptide as well as the silencing and functional inhibition of Rac1 to inhibit intracellular superoxide production as well as overcome Bcl-2-mediated drug resistance in human leukemia and cervical cancer cells. Notably, the interaction was observed in primary cells derived from patients with B-cell lymphoma overexpressing Bcl-2 but not in noncancerous tissue. In an attempt to study the functional implication of this interaction, we carried out a computer simulation driven virtual predictive experiments based on the protein pathway dynamic network created by Cellworks Group Inc. The base line used for the study was a KRAS over-activated, PI3K overexpressed, CDKN2A deleted, β-catenin overexpressed and Bcl-2 overexpressed system aligned to HCT116 human colorectal cancer cell line. When a variant of the above base line was created with Rac1 overexpression, phenotypic indices of angiogenesis, proliferation, viability, metastasis as well as tumor volume were all upregulated. Strikingly, the expression levels of STAT3 and β-catenin were significantly amplified in the computer modeled variant cell line; however upon Rac1 or Bcl-2 knockdown in both the base and the variant cell lines, apoptotic markers such as Bax, caspase 3 and cleaved PARP1 were increased while STAT3, β-catenin, NF-κB and AGER were significantly down-regulated. Intrigued by these predictions, we set out to verify the link between STAT3 signaling and Bcl-2-Rac1 interaction. Interestingly, the activation status of STAT3 (pY705) strongly correlated with Bcl-2 expression as well as Rac1 activation status. Furthermore, STAT3 was found localized to mitochondria and preliminary results suggest an interaction with Bcl-2.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C149.
Abstract C15: Combined blockade of AKT kinase with gemcitabine overcomes FKBP5-mediated resistance of inhibition of pancreatic tumor growth.
Authors: Hou Junmei , Wang Liewei 
Published: June 2012

Abstract
We have recently showed that the immunophilin FKBP5 (also known as FKBP5) as a scaffolding protein that can enhance PHLPP-AKT interaction and facilitate PHLPP-mediated dephosphorylation of AKT-Ser473, negatively regulating AKT activation in vitro. Therefore, FKBP5 might function as a tumor suppressor and levels of FKBP5 would affect cell response to chemotherapy. In the current study, we took a step forward by using pancreatic caner xenograft mice model to show that FKBP5−/− promotes tumor growth and renders resistance to gemcitabine and addition of AKT inhibitors have more significant sensitization effect on FKBP5−/− mice to gemcitabine treatment. The combination of triciribine and gemcitabine resulted in cooperative inhibition of pancreatic cancer cell proliferation and the growth of xenografts in vivo without increasing toxicity, as well as cooperative inhibition of AKT signaling pathways at concentrations that were ineffective as individual agents. These results provide evidence for future clinical studies designed to tailor the therapy based on the biomarker.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C15.
Abstract C154: microRNA and targets in the poor prognosis of ovarian cancer patients.
Authors: Cui Shiying , Zhao Henan , Ding Yanfang , Zhao Jinyao , Bi Tie , Jiang Jiyong 
Published: June 2012

Abstract
Epithelial ovarian cancer (EOC) is the most important cause of gynecologic malignancy-related mortality in women. Ovarian clear cell carcinoma (CC) has a poor survival rates and ovarian papillary serous carcinoma (PSC) has a high incidence in the EOC. To get the insight of possible regulator and pathway that may involved in the EOC prognosis and progress, patient samples of CC, PSC and normal ovarian or oviduct tissues were employed in the study. Total 48 human tumor samples and 6 normal ovarian and oviduct tissues were obtained from the patients who were surgically treated for ovarian cancer or other disease at the Obstetrics and Gynecology Hospital, Dalian China. The tissue was further fixed by formalin and embedded by paraffin as routine. Total RNA that enriched miRNAs was extracted from the FFPE tissue by using the Ambion mirVana microRNA isolation kit (Ambion, Austin TX). The quality of total RNA was assessed using the Agilent Bioanalyzer (Agilent Technologies, Santa Clara CA). Quantitative Real-Time polymerase chain reaction (qRT-PCR) assays were formatted into a TaqMan low-density array (TLDA; Applied Biosystems), which was performed at the Shannon McCormack Advanced Molecular Diagnostics Laboratory Research Services, Dana Farber Cancer Institute, Harvard Clinic and Translational Science Center. The normalized microarray data were managed and analyzed by Statminer version 3.0. The targets of miRNA were predicted by using computational approaches, the MicroCosmTargets version 5 and miRBase. The pathway was analyzed by commercial available Ingenuity software. Finally the target predicted was validated by qRT-PCR and imunohistochemistry.
The results showed that 101 miRNAs are differentially expressed in the patients of CC compared with PSC, of which 86 (85%) miRNAs were down-regulated in CC patients, suggesting a majority of regulators in the poor prognosis of CC are tumor suppressors. The key miRNAs that were down-expressed in CC patients are miR-9, miR-202, miR-488, miR-509–5p and up-expressed are miR-217, and miR-550. Hundred of gene targets and protein target on the pathways were predicted, but the top targets are enhancer of polycomb homolog 1 (EPC1) and mycophyta (c-MYC), which were validated by qRT-PCR assay at mRNA level and confirmed by immunohistochemistry at molecules level.
We identified the key miRNAs that differentially expressed in patients of CC and PSC tumors, predicted and validated the most popular targets regulated by the key miRNAs, indicating the possible regulation gene and pathway for EOC prognosis.
This work was supported by the Ministry of Science and Technology of China, Program No. 2008DFA30720 to Shiying Cui.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C154.
Abstract C155: Inhibition of TAK1 promotes apoptosis in KRAS and Wnt pathway codependent colon cancers.
Authors: Singh Anurag , Sweeney Michael F. , Settleman Jeff , Haber Daniel A. 
Published: June 2012

Abstract
Colorectal cancers frequently harbor KRAS mutations but KRAS-mutant cancers are refractory to conventional and targeted therapeutics. The primary aim of this study was to identify novel therapeutic strategies to target KRAS-mutant colon cancers. Firstly, we found that a subset of KRAS-mutant colorectal cancer cell lines are dependent upon KRAS signaling for survival. Secondly, we found that KRAS-dependent colorectal cancer cells require the TAK1 kinase (MAP3K7) for sustained viability. TAK1 depletion or the small molecule TAK1 kinase inhibitor 5Z-7-oxozeaenol results in profound apoptotic cell death in KRAS-dependent cells. Lastly, we noted that sensitivity to TAK1 disruption is associated with enhanced Wnt signaling resulting from APC mutations combined with KRAS hyperactivation. This effect can be attributed in part to a KRAS-mediated activation of BMP signaling, leading to TAK1 activation. TAK1 then directly regulates Wnt signaling specifically in KRAS-dependent cells. In primary human colorectal cancers, expression of a gene signature derived from TAK1-dependent cell lines is correlated with APC and KRAS mutational status. Thus, our studies reveal TAK1 inhibition as a potential therapeutic strategy for the generally treatment-refractory subset of colorectal cancers that are driven by the KRAS and Wnt pathways.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr C155.