bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract 3705: Overcoming drug resistance in BRaf mutated melanoma cells
Authors: Samadani Ramin , Zhang Jun , Mackerell Alexander , Fletcher Steven , Shapiro Paul 
Published: May 2015

Abstract
Targeted inhibition of the ERK1/2 signaling pathway has received much attention after the transient success of the BRaf inhibitor, vemurafenib, in metastatic melanoma patients with the BRafV600E mutation. Approximately 50% of melanomas have an activating mutation to BRaf which drives cancer cell proliferation and survival through the ERK pathway. Therapies targeting BRaf or its downstream kinase MEK1/2 have demonstrated very promising initial clinical results. However, these treatments invariably lead to drug resistance through the activation of alternate pathways or mutations that circumvent the blockade and reactivate ERK1/2. Current efforts are centered on the use of combination therapies as well as the direct inhibition of ERK1/2 itself. The purpose of this study is to examine the effects of putative substrate-selective ERK inhibitors in various clinically relevant models of drug resistance. Specifically melanoma cell lines resistant to BRaf and MEK inhibitors, PLX-4032 and AZD-6244 respectively, were generated to test the efficacy of these novel compounds in cell viability assays. Furthermore, the potency of these molecules was evaluated in the context of activating mutations to MEK1 and drug resistant cell lines that overexpress MAP3K8 (the gene encoding COT/Tpl2). The data shows that these putative substrate-selective ERK inhibitors preferentially inhibit proliferation of cell lines with activated ERK1/2 signaling. In addition, these novel molecularly targeted therapies are equipotent in drug resistant versus non-resistant melanoma cells. Given these compounds' selectivity for BRaf mutated melanoma cells and their efficacy in drug resistance models, we submit these novel chemical entities as potential lead candidates for new salvage therapies in patients who have become resistant to currently available treatments. Moreover, these ATP-independent inhibitors target only select ERK1/2 functions and may be inherently less susceptible to developing their own drug resistance as compared to complete ablation of all ERK1/2 signaling as seen with ATP-competitive inhibitors.
Citation Format: Ramin Samadani, Jun Zhang, Alexander Mackerell, Steven Fletcher, Paul Shapiro. Overcoming drug resistance in BRaf mutated melanoma cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3705. doi:10.1158/1538-7445.AM2014-3705
Abstract 3711: Erk inhibition as a therapeutic option for the treatment of Raf- and Mek- inhibitor resistant tumors
Authors: Seipelt Irene , Schmidt Peter , Maerzhaeuser Helene , Gerlach Matthias , Jung Kai , Schuster Tilmann , Teifel Michael 
Published: May 2015

Abstract
The MAPK pathway represents a prime target for therapeutic intervention in cancer. Recent approvals of B-Raf and Mek inhibitors lead to exciting antitumor activities and survival benefits. However the observation of resistance to such Raf and Mek inhibitors has been documented in both clinical and preclinical trials. These phenomena stimulated further research into the regulation of the MAPK pathway and led to the suggestion to target the downstream kinase Erk, as well as to combine its targeting with Raf and Mek inhibitors.
Here we report that Erk inhibitors result in efficient growth inhibition of tumor cells that are resistant to Raf and Mek inhibitors. AEZS-134 - a highly potent and selective ATP competitive Erk inhibitor - overcomes the Raf inhibitor induced paradoxical cell activation and the aquired resistance to Mek inhibitors in tumor cells. We demonstrate potent antiproliferative activity of AEZS-134 in B-Raf wildtype, B-RafV600E mutant, Ras wildtype and K-Ras mutant tumor cell lines in comparison to common Raf inhibitors. Furthermore we show that AEZS-134 is efficacious in Mek inhibitor resistant Hct116 and MDA MB231 cells which have been well characterized in terms of Mek F129L allosteric binding pocket mutation, varying degrees of K-Ras amplification, cellular proliferation assays and MAPK pathway phosphorylation studies.
Our data provide a rational for new therapeutic opportunities by using Erk inhibitors in oncology. In order to maximize therapeutic benefit for patients and considering that Erk is directly downstream of B-Raf and Mek, targeting Erk may be more effective than targeting Raf or Mek in a variety of MAPK resistance settings. AEZS-134 and related compounds provide potent and selective tools to help address this question.
Development of the Erk inhibitors by Æterna Zentaris is integral part of our inhouse kinase research program comprising the investigation of different compounds for single Erk inhibition, single PI3K inhibition and dual kinase inhibitions of Erk and PI3K. All compounds are exclusively synthesized by our medicinal chemistry department.
Citation Format: Irene Seipelt, Peter Schmidt, Helene Maerzhaeuser, Matthias Gerlach, Kai Jung, Tilmann Schuster, Michael Teifel. Erk inhibition as a therapeutic option for the treatment of Raf- and Mek- inhibitor resistant tumors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3711. doi:10.1158/1538-7445.AM2014-3711
Abstract 3719: Mechanisms of resistance to the second-generation alk inhibitor ap26113 in human npm-alk-positive anaplastic large cell lymphoma cells
Authors: Ceccon Monica , Mologni Luca , Giudici Giovanni , Piazza Rocco , Pirola Alessandra , Fontana Diletta , Gambacorti-Passerini Carlo 
Published: May 2015

Abstract
ALK is a tyrosine kinase receptor involved in a broad range of solid and haematological tumors. It has been shown that about 70-80% of ALK+ Anaplastic Large Cell Lymphoma (ALCL) cases, an aggressive Non Hodgkin T-cell lymphoma, are characterized by the traslocation t(2;5), originating the functional, aberrant oncogenic fusion protein NPM-ALK. Crizotinib was the first clinically relevant ALK inhibitor, now approved for the treatment of late stage and metastatic cases of lung cancer. Several patients soon developed Crizotinib resistance, mainly due to the appearance of new point mutations located in ALK kinase domain. Currently, other ALK inhibitors are available and already in clinical trial, hopefully representing the second line therapy able to overcome Crizotinib resistance. In this work we focused our attention on the more potent phase I/II dual ALK/EGFR inhibitor AP26113 (Ariad Pharm.), able to overcome the Crizotinib-resistant gatekeeper mutation L1196M. Two NPM-ALK+ human cell lines, KARPAS-299 and SUP-M2, were grown in four independent flasks in the presence of increasing doses of AP26113, so that eight cell lines able to grow in the presence of high AP26113 doses were selected. All cell lines show an AP26113 50% inhibitory concentration (IC50) value substantially higher than the one observed in parental cells, with a 130 to 1000-fold increase. All KARPAS-299 populations resistant to AP26113 show NPM-ALK overexpression, due to oncogene amplification, as the main cause of resistance, while SUP-M2 cells proliferating in the presence of the drug harbour several point mutations spanning the entire ALK kinase domain. In particular, we identified the following aminoacid substitutions: L1122V, , L1196M, S1206C and a double F1174V+L1198F mutation. The knowledge of the possible appearance of new clinically relevant mechanisms of drug resistance is a useful tool for the management of new TKI resistant cases.
Citation Format: Monica Ceccon, Luca Mologni, Giovanni Giudici, Rocco Piazza, Alessandra Pirola, Diletta Fontana, Carlo Gambacorti-Passerini. Mechanisms of resistance to the second-generation alk inhibitor ap26113 in human npm-alk-positive anaplastic large cell lymphoma cells. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3719. doi:10.1158/1538-7445.AM2014-3719
Abstract 3722: The HSP90 inhibitor ganetespib synergizes with the MET kinase inhibitor crizotinib in both crizotinib-sensitive and crizotinib-resistant MET-driven renal tumor models
Authors: Miyajima Naoto , Akino Tomoshige , Tsuchiya Kunihiko , Maruyama Satoru , Abe Takashige , Shinohara Nobuo , Nonomura Katsuya , Neckers Len 
Published: May 2015

Abstract
Introduction: The proto-oncogene MET is aberrantly activated via overexpression or mutation in numerous cancers including papillary renal carcinoma, making it a prime anti-cancer molecular target. However, the clinical success of MET-directed tyrosine kinase inhibitors (TKI) has been limited due, in part, to mutations in the MET kinase domain that confer therapeutic resistance. Circumventing this problem remains a key challenge to improving durable responses in patients receiving MET-targeted therapy. Small molecule HSP90 inhibitors cause HSP90 to dissociate from its client proteins, resulting in their destabilization and eventual degradation. HSP90 inhibitors have been validated in numerous preclinical tumor models and have shown promising activity in several clinical trials. Given the distinct mechanisms of action of TKI and HSP90 inhibitors, we evaluated the synergistic effects of these two drugs on both TKI-sensitive and TKI-resistant MET-driven tumor models.
Methods: We tested efficacy of the MET TKI crizotinib, the HSP90 inhibitor ganetespib and their combination in MKN45, wild-type MET-overexpressed cell line and MET-Y1248H, TKI-resistant mutant MET- verexpressed cell line in vitro. The antitumor efficacy of HSP90 inhibition in vivo was verified in xenograft models.
Results: MET is an HSP90-dependent kinase, and we show that HSP90 preferentially interacts with and stabilizes activated MET, whether the activation is ligand-dependent or is a consequence of kinase domain mutation. In contrast, many MET TKI show a preference for the inactive form of the kinase and activating mutations in MET can confer resistance. Combining the HSP90 inhibitor ganetespib with the MET TKI crizotinib achieves synergistic inhibition of MET, its downstream signaling pathways, and tumor growth in TKI-sensitive MET-driven tumor models. Unexpectedly, low-dose ganetespib also partially restores crizotinib sensitivity, in vitro and in vivo, to cells and tumors expressing TKI-resistant MET mutants.
Conclusion: Our findings support the use of HSP90 inhibitors to overcome or delay the initiation of resistance to MET TKI, and they provide the basis for clinical evaluation of this combination in patients with MET-driven papillary renal cancer.
Citation Format: Naoto Miyajima, Tomoshige Akino, Kunihiko Tsuchiya, Satoru Maruyama, Takashige Abe, Nobuo Shinohara, Katsuya Nonomura, Len Neckers. The HSP90 inhibitor ganetespib synergizes with the MET kinase inhibitor crizotinib in both crizotinib-sensitive and crizotinib-resistant MET-driven renal tumor models. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3722. doi:10.1158/1538-7445.AM2014-3722
Abstract 3725: HGF/c-Met axis drives cancer aggressiveness in the neo-adjuvant setting of ovarian cancer
Authors: Mariani Marisa , McHugh Mark , Petrillo Marco , Sieber Steven , He Shiquan , Andreoli Mirko , Fiedler Paul , Scambia Giovanni , Shahabi Shohreh , Ferlini Cristiano 
Published: May 2015

Abstract
Background: Ovarian cancer is the most lethal gynecologic malignancy. Recently, NACT has been clinically tested as alternative approach for the management of ovarian cancer patients. A biological predictor helpful in selecting patients for NACT would be desirable. Indeed, chemotherapy has a strong impact in modifying the biology of tumor and rendering it more aggressive. This study was aimed at identifying actionable mechanisms of resistance to NACT.
Methods: Expression of a panel of microRNAs was screened in a discovery set of 85 patients. Analysis of the potential targets was conducted in the same RNAs by calculating significant correlations between microRNAs and genes. Quantitative fluorescent immunohistochemistry was employed in a validation set of 109 patients. Pre and post-NACT specimens were analyzed in multiple cores of tumor from formalin fixed paraffin embedded material (FFPE).
Results: MiR-193a-5p was significantly overexpressed in the NACT setting. Analysis of its potential targets demonstrated that this microRNA is also significantly correlated with the expression levels of HGF and MET genes. Analysis of protein expression in samples taken before and after NACT demonstrated that both HGF and c-Met are increased after NACT. Patients who relapse shortly after NACT exhibited the highest relative basal expression of both HGF and c-Met, while the opposite phenomenon was observed in the best responders.
Conclusion: These findings demonstrate that NACT refractory patients express activation of the HGF/c-Met pathway. HGF/c-Met expression may help select eligible patients for this modality of treatment. Moreover, inhibitors of this pathway may improve the efficacy of NACT.
Citation Format: Marisa Mariani, Mark McHugh, Marco Petrillo, Steven Sieber, Shiquan He, Mirko Andreoli, Paul Fiedler, Giovanni Scambia, Shohreh Shahabi, Cristiano Ferlini. HGF/c-Met axis drives cancer aggressiveness in the neo-adjuvant setting of ovarian cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3725. doi:10.1158/1538-7445.AM2014-3725
Abstract 3727: Drug screen on six co-cultured GBM cell lines using a multiplex luciferase assay
Authors: Rijn Sjoerd van , Hiddingh Lotte , Wurdinger Thomas , Narayan Ravi 
Published: May 2015

Abstract
Despite the addition of temozolomide (TMZ) to the glioblastoma (GBM) treatment regimen, disease outcome is still poor and additional therapeutic options are necessary. One major obstacle in the GBM treatment is TMZ resistance of the tumor cells resulting in relapse of the disease with no alternative treatments known. In an effort to discover additional treatment modalities we are performing drug screens on GBM cell lines, using wild-type variants and acquired TMZ resistant variants of these cell lines.
To be able to screen a range of different cells, we adapted a multiplex bioluminescence reporter assay developed in our lab. This bioluminescent reporter assay is based on the Gaussia luciferase (Gluc) fused to an epitope tag. Different cell lines can be equipped with Gluc fused to different epitope tags (Gluc-tag) so that each cell lines expresses Gluc and a cell line specific epitope tag. Antibody immunoprecipitation allows us to separate the different Gluc-tags and quantify the relative activities of the different cell lines. Activity of each specific Gluc-tag represents the relative number of a specific cell line in the mixed population. Since Gaussia luciferase and the epitope tag is secreted by the cells, we can detect the cell line specific reporters ex vivo in the culture medium or animal blood.
Using this novel method in a drug screen we aim to identify additional subtype specific therapy strategies for GBM braintumors.
Citation Format: Sjoerd van Rijn, Lotte Hiddingh, Thomas Wurdinger, Ravi Narayan. Drug screen on six co-cultured GBM cell lines using a multiplex luciferase assay. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3727. doi:10.1158/1538-7445.AM2014-3727
Abstract 3731: Luminescent cell health assays for tumor spheroid evaluation
Authors: Valley Michael P. , Kupcho Kevin R. , Zimprich Chad A. , Niles Andrew L. , Cali James J. , Kelm Jens M. , Moritz Wolfgang , Lazar Dan F. 
Published: May 2015

Abstract
Microtissues produced in 3D cell culture are much more representative of actual living tissue compared to monolayers produced in 2D cell culture. In fact, in the area of oncology research, multicellular tumor spheroids are considered an excellent platform for testing drug delivery and efficacy. As the necessity for established 3D cell culture models rises, there is also a need for convenient assays that have been specifically demonstrated to be effective for use with 3D microtissues. The more complex architecture of 3D microtissues demands increased lytic effectiveness and reagent penetration, characteristics that are often only minor considerations for reagents designed for 2D cell culture. Here we report on a variety of bioluminescent and fluorescent cell-based assays applied to hanging-drop spheroids produced from HCT116 colon cancer cells. The first assay to be described is an ATP detection reagent for measuring cell viability. This reagent has both an improved formulation and an optimized assay protocol and has clear advantages over other viability assays. Other cell health assays will also be described, including reagents that measure cell death, apoptosis, mechanistic cytotoxicity, or reporter gene expression. These additional assays do not require a change in formulation, but do require new protocols in order to optimize their effectiveness when applied to 3D microtissues. As with their application to cells in 2D culture, these “add-mix-measure” reagents are robust and amenable to both low- and high-throughput applications.
Citation Format: Michael P. Valley, Kevin R. Kupcho, Chad A. Zimprich, Andrew L. Niles, James J. Cali, Jens M. Kelm, Wolfgang Moritz, Dan F. Lazar. Luminescent cell health assays for tumor spheroid evaluation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3731. doi:10.1158/1538-7445.AM2014-3731
Abstract 374: A novel sequencing method for genome-wide profiling of 5-hydroxymethylcytosine with single-base resolution
Authors: Sun Xueguang , Chung Tzu-Hung , Chew Yap Ching , Tan Darany , Jia Xi-Yu 
Published: May 2015

Abstract
5-hydroxymethylcytosine (5hmC) is an epigenetic mark abundant in embryo stem cells and brain tissues. The exact biological functions of 5hmC are still under close investigation although several lines of evidence have indicated it could be involved in active DNA demethylation. Meanwhile, extensive studies have been carried out to determine its genomic distribution. A number of approaches have been developed using either affinity based enrichment, such as hMeDIP, that rely on antibody and other specific binding proteins to target 5hmC, or modified bisulfite sequencing, namely oxidative bisulfite sequencing (OxBS) and TET assisted bisulfite sequencing (TAB-sequencing). However, all those methods have limitations which hamper their application. For example, affinity based methods lack single base resolution while modified bisulfite sequencing methods require efficient chemical or enzymatic oxidation which cannot be easily achieved or guaranteed. As an alternative, we have developed a novel genome-wide sequencing method that utilizes an enzyme based modification approach coupled with bisulfite-sequencing for detecting 5hmC. This methodology allows quantification of 5hmC levels with single CpG resolution and can also be employed for locus-specific assays. Using this method, we were able to map and quantify 5hmC sites at the genomic scale for several different biological samples. This novel method can determine the exact location and abundance of 5hmC, which will facilitate our understanding of 5hmC in regulating gene expression in different biological contexts.
Citation Format: Xueguang Sun, Tzu-Hung Chung, Yap Ching Chew, Darany Tan, Xi-Yu Jia. A novel sequencing method for genome-wide profiling of 5-hydroxymethylcytosine with single-base resolution. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 374. doi:10.1158/1538-7445.AM2014-374
Abstract 3744: High-throughput in vitro screening of glioma stem cell lines: Evaluation of over 350 tyrosine kinase inhibitors
Authors: Thomas Craig , Liang Ji , Piao Yuji , Nguyen Nghi , Sulman Erik , Stephan Clifford , Yung Alfred , Groot John F. de 
Published: May 2015

Abstract
Despite the availability of hundreds of drugs, there is little data on the efficacy of these agents in the extremely heterogeneous populations of tumor cells observed in glioblastoma. A high-throughput compound-screening assay was used to identify drug sensitivities in a panel of glioma stem cell (GSC) lines to 350 tyrosine kinase inhibitors (GSK PKIS1) with varying cellular targets and mechanisms of kinase inhibition. Twelve glioma stem cell lines, which are representative of the classic TCGA molecular subtypes, were screened. Cell lines were screened in 384-well plates at a density of 1000 cells/well with drug concentrations of either 5 or 0.5 µM. Cell viability measurements were taken using Cell-Titer Glo five days after drug treatment and compared to control wells to calculate percentage inhibition. Compounds were defined as highly active (&gt;90 % inhibition at 5µM; &gt; 50% inhibition at 0.5µM), moderately active (&gt;70% inhibition at 5µM; &gt;30% inhibition at 0.5µM), or weakly active (&gt;50% inhibition at 5µM; &gt;15% inhibition at 0.5µM.) We identified three compounds that were highly active against eleven cell lines, three more compounds that were highly effective against at least seven cell lines, and seven additional compounds that were highly effective against at least four cell lines. The compounds in the screen were further analyzed by testing their inhibition efficacy against 220 kinases. A separate set of compounds containing molecularly targeted agents to TGF-beta, STAT3, PI3K and Notch were used for comparison of drug efficacy. Ongoing experiments are being performed to fully characterize the molecular phenotypes of the different GSC's by analyzing RNAseq, miRNA, the whole exome, the proteome, DNA methylation, and copy number variation. Integrating this information with the kinase and growth inhibition data will allow us to have a complete picture of the underlying mechanisms which drive resistance/sensitivity in GSC's. After determining which kinases are the most effective targets for the treatment of glioblastoma, promising compounds will be validated in intracranial in vivo xenograft models.
Citation Format: Craig Thomas, Ji Liang, Yuji Piao, Nghi Nguyen, Erik Sulman, Clifford Stephan, Alfred Yung, John F. de Groot. High-throughput in vitro screening of glioma stem cell lines: Evaluation of over 350 tyrosine kinase inhibitors. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3744. doi:10.1158/1538-7445.AM2014-3744