bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract 2770: Antitumor activity of heat shock protein 90 (HSP90) inhibitor AT13387 in head and neck squamous cell carcinoma
Authors: Truong Kristy , Gouveia Christopher , Coupar Jamie , Smyth Tomoko , Lyons John , Chen Zhong , Waes Carter Van
Published: August 2012

Heat shock protein 90 (HSP90) has been shown to be overexpressed in a wide range of cancers, and plays a critical role in tumor cell growth and survival by stabilizing aberrant signaling proteins and by interfering with apoptosis. Several natural and synthetic inhibitors of HSP90 have been shown to have antitumor effects, but single agent development has been limited by poor solubility, poor availability and off-target toxicities (hepatotoxicity, retinal toxicity). The aim of this study is to investigate the biological activity of the small-molecule HSP90 inhibitor, AT13387 (Astex Pharmaceuticals) for antitumor activity in head and neck squamous cell carcinoma (HNSCC). Human HNSCC cell lines, UMSCC −1 (wild-type p53) and −46 (mutant p53) were treated with AT13387. The inhibitory concentrations (IC[[Unsupported Character - Codename ­]]50) of AT13387 on HNSCC cell lines were determined using MTT proliferation assay. AT13387 (55 mg/kg two consecutive days every week) antitumor activity, toxicity and survival were evaluated in the UMSCC −1 and −46 xenograft model in BALB/c SCID mice. AT13387 inhibited the proliferation of both UMSCC cell lines in vitro with IC50 levels of 0.05-.10 µM by MTT assay. In vivo, AT13387, at 55 mg/kg showed significant antitumor effect and improved survival in both wtTP53 UMSCC-1 and mtTP53 UMSCC-46 xenograft models. The treatment was well-tolerated and no significant body weight loss observed. These data suggest that AT13387 may possess potent antitumor activity in human HNSCC, regardless of the p53 mutation status. The potential of AT13387 as a chemosensitizer for radiotherapy is being investigated. These preclinical data suggest that AT13387 holds promise as a potential chemotherapeutic agent for HNSCC clinical trials. (Supported by NIDCD project ZIA-DC-000073 and AT13387 provided to NCI by Astex Pharmaceuticals)

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 2770. doi:1538-7445.AM2012-2770
Abstract 2772: AT13387, an HSP90 inhibitor, is effective in both vemurafenib-sensitive and -resistant melanoma models
Authors: Rodriguez-Lopez Ana M. , Smyth Tomoko , Curry Jayne , Graham Brent , McMenamin Rachel , Lyons John , Thompson Neil , Wallis Nicola
Published: August 2012

Background: Mutations in BRAF are found in approximately 50% of melanomas. Vemurafenib, the selective mutant BRAF inhibitor, is an effective treatment in this disease but is limited by the onset of resistance. A number of mechanisms of resistance to RAF inhibitors have been described, including alternative mechanisms for activating the MEK-ERK and AKT pathways. HSP90 inhibitors affect clients in both these pathways and so it has been suggested that HSP90 inhibition is a potential mechanism for overcoming resistance to RAF inhibitors in melanoma. Results: AT13387 is a fragment-derived, potent HSP90 inhibitor, which is currently being evaluated in clinical trials. AT13387 inhibited cell proliferation in a range of melanoma cell lines, including cell lines with different mechanisms of resistance to vemurafenib (See Table). AT13387 treatment of melanoma cell lines resulted in the induction of HSP70, a marker of HSP90 inhibition, and depletion of HSP90 client proteins including BRAF and AKT. The levels of phospho-ERK, phospho-AKT and phospho-S6 were also depleted in both vemurafenib-sensitive (A375) and vemurafenib-resistant (A2058) lines indicating that the MEK-ERK and AKT signaling pathways were both inhibited. This demonstrates that vemurafenib resistance mediated by upregulation of the AKT pathway can be overcome by HSP90 inhibition. In vivo, AT13387 significantly inhibited growth of an A375 melanoma xenograft. Client proteins, including BRAF, CRAF and AKT were depleted in xenograft tissue and the MEK-ERK and AKT signaling pathways were again inhibited. Conclusions: These results demonstrate the activity of AT13387 in both vemurafenib-sensitive and -resistant models and show that HSP90 inhibition results in downregulation of signaling pathways that may be activated as a result of resistance to RAF inhibitors. These data support further clinical evaluation of AT13387 in melanoma.

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 2772. doi:1538-7445.AM2012-2772
Abstract 2773: HSP90 inhibitors target KRAS mutant human tumors through degradation of STK33
Authors: Azoitei Ninel , Hoffmann Christopher M. , Ellegast Jana M. , Ball Claudia R. , Obermayer Kerstin , Gößele Ulrike , Koch Britta , Faber Katrin , Genze Felicitas , Schrader Mark , Kestler Hans A. , Döhner Hartmut , Chiosis Gabriela , Glimm Hanno , Fröhling Stefan , Scholl Claudia
Published: August 2012

Mutations in the KRAS proto-oncogene occur in ∼30% of human cancers and are particularly prevalent in adenocarcinomas of the pancreas, lung, and colon. Previous efforts to develop drugs that directly inhibit the activity of mutant KRAS have not met with success. We have recently shown that cancer cells driven by mutant KRAS require expression of the serine/threonine kinase STK33 for their viability and proliferation, supporting STK33 as a context-dependent therapeutic target. However, specific strategies for interfering with the critical functions of STK33, which remain to be elucidated, are not yet available. Using a mass spectrometry-based screen for STK33 protein interaction partners, we report that the HSP90/CDC37 chaperone complex and BAG2, a member of the BAG family of molecular chaperone regulators, bind to and stabilize STK33 in human cancer cells. Pharmacologic inhibition of HSP90, using structurally divergent small molecules currently in clinical development, induced proteasome-mediated degradation of STK33 in human cancer cells of various tissue origin in vitro and in vivo, and triggered apoptosis preferentially in KRAS mutant cells in an STK33-dependent manner. Furthermore, HSP90 inhibitor treatment impaired sphere formation and viability of primary human colon cancer-initiating cells harboring mutant KRAS. Similar to HSP90 inhibition, short hairpin RNA-mediated suppression of BAG2 depleted STK33, whereas BAG2 overexpression rescued STK33 protein levels in the presence of HSP90 inhibitors, resulting in diminished apoptosis in KRAS mutant cancer cells. These findings (1) provide mechanistic insight into the activity of HSP90 inhibitors in KRAS mutant cancer cells, (2) indicate that the enhanced requirement for STK33 can be exploited to target mutant KRAS-driven tumors, (3) identify STK33 depletion through HSP90 inhibition as a biomarker-guided therapeutic strategy with immediate translational potential, and (4) point to BAG2 as a candidate cancer drug target.

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 2773. doi:1538-7445.AM2012-2773
Abstract 2785: Discovery of a novel HDM2 inhibitor with potent in vivo anti-tumor activity
Authors: Wang Yaolin , Lipari Philip , Mirza Asra , Lin Yinghui , Zhang Rumin , Bogen Stephane , Bogen Stephane , Ma Yao , Hicklin Daniel J. , Seidel-Dugan Cynthia , Liu Suxing , Wang Xiaoying , Doll Ronald , Shipps Gerald , Bishop Walter Robert
Published: August 2012

HDM2 is a major negative regulator of the p53 tumor suppressor pathway. Aberrant HDM2 overexpression and gene amplification contributed to accelerated cancer development and growth. Several small molecule inhibitors of HDM2-p53 protein-protein interaction have been reported in recent years with anti-tumor activities in tumor xenograft models. Here we describe a novel and potent small molecule inhibitor of HDM-p53 inhibitor that binds selectively to HDM2 with high affinity compared to HDM4. Treatment of cancer cells with this HDM2 inhibitor results in activation of p53 pathway as demonstrated by study of pharmacodynamic biomarkers both in cell culture and in tumor xenograft in vivo. More importantly, cancer cells response to this HDM2 inhibitor is mechanism based and dependent on the presence of functional p53 status as shown in a profiling of a broad-panel of cancer cell lines. This inhibitor is very potent against cancer cell growth with IC50 below 200 nM for most cell lines tested in vitro. It is orally bioavailable and has single agent activity that results tumor regression in SJSA-1 osteosarcoma model or growth inhibition in A549 NSCLC and A2780 ovarian cancer xenograft models. In addition, combination of this HDM2 inhibitor with various chemotherapy agents results in added or synergistic anti-tumor response both in vitro and in vivo in several human cancer xenograft models with limited bone marrow toxicity at the efficacious dose.

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 2785. doi:1538-7445.AM2012-2785
Abstract 2900: Redox nanoparticle enhances effect of anticancer chemotherapy and suppresses cardio-toxicity
Authors: Nagasaki Yukio , Ozaki Yuki , Yoshitomi Toru
Published: August 2012

Utilizing the self-assembled core-shell-type polymeric micelle technique, high-performance nanoparticles possessing stable nitroxide radicals in the core and reactive groups on the periphery were prepared (Nitroxide Radical-containing Nanoparticles; RNP). The average diameter of the nanoparticles was ca. 40 nm, and the nanoparticles emitted intense electron paramagnetic resonance (EPR) signals. Owing to the confinement of the nitroxide groups in the core of the nanoparticles, it reduces its toxicity, prolongs its blood circulation time. Under the low pH environment in vivo, it was confirmed that RNP disintegrated to expose the nitroxide radicals outside of the particle. It is sharp contrast against low-molecular-weight TEMPOL, which was reduced and excreted rapidly from the blood stream. Recently, we have reported that RNP is effectively worked to cerebral ischemia reperfusion injury. The RNP disintegrates in penumbra area due to the acidosis of ischemic region, followed by the scavenging reactive oxygen species (ROS) generated in this area. This strategy could be applied to other ischemic injuries such as renal and myocardial infarction. Quite recently, we have found that scavenging of ROS in tumor region by RNP improves efficiency of anticancer drug, doxorubicin (DOX). For example, RNP administration prior to the DOX-injection remarkably improved its efficiency. When RNP was administered via mice tail veil, it accumulated in tumor due to the enhancement permeation and retention (EPR) effect. The accumulated RNP scavenged excessive generated ROS in tumor, which suppressed activation of transcription factors such as NF-κB. Such suppression of inflammation related transcription factors might increase effectiveness of anticancer drug such as doxorubicin (DOX). The RNP pre-administration also reduced its side effect. Actually, 25mg/kg intravenous administrations of RNP before and after the DOX-injection (20mg/kg) reduced significantly the lactate dehydrogenase (LDH) and the creatine phosphokinase (CPK) activity. Thus, the nanoparticle anti-oxidant treatment is promising as a new adjuvant for anti-cancer chemotherapy without severe side effect by anticancer drug.

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 2900. doi:1538-7445.AM2012-2900
Abstract 2901: Development of mannose-polyethyleneglycol-modified liposomes for idiopathic thrombocytopenic purpura
Authors: Fujimura Tetsuo , Sugiyama Ikumi , Murai Kazunori , Ishida Yoji , Oku Naoto , Sadzuka Yasuyuki
Published: August 2012

[Objective]Idiopathic thrombocytopenic purpura(ITP) among thrombocytopenia is an acquired autoimmune disease and is not clear on the cause of disease. ITP is produced antibodies to the platelet by immunological action and is thrombocytopenia with platelet phagocytosis by macrophages in the spleen. There is a few deaths by the thrombocytopenia, whereas its effective treatment has not been developed. Polyethyleneglycol(PEG) modification of liposome as drug carrier is known to provide blood circulation. The surface of macrophages is overexpressed mannose receptor. Namely, mannose-PEG-modified liposome contained cytotoxic agent is expected to accumulate in macrophage and show cytotoxic effect. The effect of novel therapy for ITP was examined on platelet count and tissue distribution of cytotoxic agent. [Methods]Doxorubicin(DOX) as cytotoxic agent, containing liposome(LDOX), PEG-modified LDOX(PEG-LDOX) and mannose-modified PEG-LDOX(Man-PEG-LDOX) were prepared by remote loading method. ITP model mouse was created by administration of anti-platelet antibodies. Each liposome was administered from the tail vein in the ITP model mouse. On 24hr after each liposome administration, the platelet count was measured and DOX concentration was determined in each tissue. [Results]ITP model mouse was reduced to 7.1% of normal platelet count by anti-platelet antibodies treatment. In LDOX and PEG-LDOX groups, the platelet count does not recover to normal level and DOX concentration in the spleen was low. In contrast, the platelet count in Man-PEG-LDOX group recovered to normal level. Furthermore, DOX concentration in the spleen after Man-PEG-LDOX treatment showed a 2.7-fold of that in LDOX group. [Discussion]To be effective splenectomy for ITP treatment, it is prospected that the accumulation of cytotoxic agent in the spleen is useful. As liposome with PEG-modification has been developed for avoiding the reticuloendotherial system cells such as liver and spleen, this liposome can not show accumulation in the spleen and cytotoxic effect on the macrophages. Thus, PEG-modified liposome is unable to suppress platelets reduction by macrophage phagocytosis. In contrast, after Man-PEG-LDOX administration, DOX concentration in the spleen significantly increased, and thus the platelet count was recovered by cytotoxic effect on the macrophages. Furthermore, DOX accumulations in the heart and other normal tissue in the Man-PEG-LDOX group were lower levels, and DOX induced adverse reaction was expected to be not observed. In conclusion, Man-PEG-LDOX is hoped to be effective as novel treatment for ITP.

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 2901. doi:1538-7445.AM2012-2901
Abstract 2902: Polymeric nanoparticles enhance the bioavailability of the chemopreventive compound SR13668 in beagle dogs
Authors: Banerjee Aryamitra A. , Shen Hao , Hautman Mathew , Anwer Jaseem , Kapetanovic Izet M. , Liu Ying , Lyubimov Alexander V.
Published: August 2012

Chemopreventive compound SR13668 showed promising anti-cancer activity in several in vitro and in vivo models of cancer, including breast, lung, prostate, and ovary and it was proposed that SR13668 works through the modulation of PI3K/Akt pathway. However, low oral bioavailability substantially limited its development as a chemopreventive agent. A novel nano-formulation of SR13668 encapsulated in poly(lactic-co-glycolic acid) (PLGA) was produced with the aim to enhance the oral bioavailability of SR13668 in beagle dogs. A single gavage administration of SR13668 was performed at 2.8 mg/kg as nano-formulation and also as SR13668 in 0.5 % methylcellulose in 4 male and 4 female dogs. Whole blood and plasma samples withdrawn from these animals at different time points over 24 hr period were analyzed using LC-MS/MS method to obtain the systemic drug levels and to evaluate the pharmacokinetic profile achieved. In plasma the group mean highest concentration occurred at the 4 hr time point in both males (29.6 ng/mL) and females (27.9 ng/mL) whereas in whole blood the mean group peak occurred at 4 hr in males (51.7 ng/mL) and 6 hr in females (61.9 ng/mL). The animals dosed with SR13668 in methylcellulose had all levels below limit of quantitation (1.1 ng/mL) in both plasma and whole blood for all time points. This study was the first attempt of using nano-formulation to improve oral bioavailability of the chemopreventive compound SR13668 in large animals. The systemic levels achieved were high for this poorly bioavailable compound in dogs but were not to the desired levels and further work is needed to improve bioavailability using nano-formulations. Potential improvements that are planned for the SR13668 nano-formulations include using a high through-put screening method to optimize the conditions further, use of polyethyleneglycol- poly(lactic-co-glycolic acid) (PEG-PLGA) for SR13668 encapsulation and comparison with poly(ethylene oxide)-b-poly(epsilon-caprolactone) (PEG-b-PCL) and PLGA results to possibly obtain better absorption with increased stability in the gut and also placement of negative charges on the nano-particles using poly-acrylic acid (PAA) to facilitate the particle penetrating the mucus layer to increase bioavailability.

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 2902. doi:1538-7445.AM2012-2902
Abstract 2903: Therapeutic targeting of leukemia and lymphoma with a neuropilin-1 binding pro-apoptotic peptide
Authors: Karjalainen Katja , Jaalouk Diana E. , Bueso-Ramos Carlos E. , Zurita Amado J. , Kuniyasu Akihiko , Eckhardt Bedrich L. , Marini Frank C. , Lichtiger Benjamin , O'Brien Susan , Kantarjian Hagob M. , Cortes Jorge E. , Koivunen Erkki , Arap Wadih , Pasqualini Renata
Published: August 2012

Targeted drug delivery offers an opportunity for the development of safer and more effective therapies for the treatment of cancer. In this study, we sought to identify short cell-internalizing peptide ligands that bind to specific cell surface receptors on malignant hematopoietic cells. Such targeting motifs could also serve as vehicles for preferential delivery of cytotoxic agents to leukemias and lymphomas. By screening of human leukemia cells with a combinatorial phage display peptide library, we isolated a peptide motif, sequence FF/YXLRS, which bound to human leukemia and lymphoma cell lines as well as to primary human acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) bone marrow specimens obtained from patients. The motif was internalized through a receptor-mediated pathway, and we next identified the corresponding receptor as the transmembrane glycoprotein neuropilin-1 (NRP-1). Moreover, the functional relevance of this internalizing receptor was evaluated in the context of disease progression via the targeted delivery of a pro-apoptotic peptidomimetic to leukemia and lymphoma cells, and a potent anti-leukemia cell effect was observed both with cell lines and patient samples when the targeting motif was synthesized in tandem to the pro-apoptotic sequence D(KLAKLAK)2. Markedly, the pro-apoptotic peptide did not have an effect on purified mononuclear cells from normal bone marrow cells. Finally, our results confirmed increased expression of NRP-1 in representative human leukemia and lymphoma cell lines and in a panel of bone marrow specimens obtained from patients with ALL or AML compared to normal bone marrow specimens. Taken together, our results indicate that NRP-1 could, potentially, be used as a target for ligand-directed therapy in human leukemias and lymphomas - as well as in many human solid tumors, which are also know to over-express NRP-1 - and that the prototype CGFYWLRSC-GG-D(KLAKLAK)2 is a promising drug candidate in this setting.

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 2903. doi:1538-7445.AM2012-2903
Abstract 2904: EGFR-targeted gold liposome for molecular imaging and therapy on NSCLC cells
Authors: Yokoyama Tomohisa , Osato Yoichi , Miyazawa Keisuke , Miyasato Akime , Hayabe Hiroko , Nomura Masaharu , Gotoh Noriko , Itoi Takao , Tauchi Tetsuzo , Ikeda Norihiko , Ohyashiki Kazuma
Published: August 2012

Nanotechnologies are in development for monitoring drug delivery and therapeutic effect for cancer. However, tumor-targeted multifunctional nanoparticles for imaging of and therapy of lung cancer are not available. The Epidermal growth factor receptor (EGFR) is overexpressed in approximately 80% of non-small cell lung cancer (NSCLC) and is a target for novel therapeutics, however, the clinical results using EGFR inhibitors for NSCLC treatment had mixed results. These results indicate that EGFR expression or its mutational status is solely not a reliable marker to determine the outcome. Therefore, we have developed liposome (120nm) encapsulated with colloidal gold that are conjugated to therapeutic anti-EGFR antibodies (Katayama Chemical Industries Co. Ltd. Osaka, Japan) to determine the molecular specific imaging of NSCLC. The colloidal gold is used for optical imaging and the anti-EGFR antibody for therapy. In the present study, we investigated in vitro effect of these liposomes on EGFR-expressing (HCC827 and H1299) and EGFR-null (H520) NSCLC cells. EGFR-targeted liposome exhibited a strong antitumor effect on EGFR-expressing NSCLC cells. On the other hands, no significant growth inhibitory effects were observed on non-targeted liposome-treated cells. Intriguingly, treatment with EGFR-targeted liposome resulted in significantly higher cell death as compared with anti-EGFR antibody and liposome alone. Furthermore, reflected polarizing microscopy showed that the concentration of EGFR-targeted liposome bound to EGFR-expressing NSCLC cells increased, but EGFR-null cells did not. When EGFR was inhibited pharmacologically, the binding efficiency of EGFR-targeted liposome was attenuated on EGFR-expressing NSCLC cells. These findings indicate that EGFR-targeted liposome are selectively bound and delivered to EGFR expressing NSCLC cells but not the EGFR-null NSCLC cells. We are currently determining in vivo effect of EGFR-targeted liposome using subcutaneous HCC827 and H520 tumor models. Our findings demonstrated that EGFR-targeted liposome is a promising agent for therapy and molecular imaging of NSCLC.

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 2904. doi:1538-7445.AM2012-2904
Abstract 2914: Creation of a novel biochemical and biophysical assay suite to enable the identification of inhibitors targeting inactive kinases
Authors: France Dennis S. , Chen Chang-Rung , Volckova Erika , Eathiraj Sudharshan , Cornell-Kennon Susan , Huang Li , McSweeney Denise , Szwaya Jeffrey , Palma Rocio , Ashwell Mark A. , Chan Thomas C.k.
Published: August 2012

We have recently reported the implementation of a structural biology-based drug design platform for the identification of protein kinase inhibitors which utilize hydrophobic clusters to stabilize the inactive state of a kinase. These clusters are not formed in active kinases and result in the conversion of the ATP binding cleft into a non-polar environment which is sterically and electrostatically incompatible with ATP binding. We have industrialized this approach, designated the ArQule Kinase Inhibitor Platform (AKIPTM), and synthesized a library of more than 15,000 small molecules through the application of an in silico guided process. This has allowed us to rapidly generate leads to a variety of kinases, including receptor tyrosine kinases, non-receptor tyrosine kinases, and serine-threonine kinases. By virtue of their unique binding modes, many of these inhibitors would not be identified in standard assays using highly activated kinases. We have therefore deliberately re-engineered standard biochemical kinase assays using unphosphorylated inactive kinases to aid in the optimization of these inhibitors. In addition to these biochemical assays, we have also implemented a variety of well-established technologies not commonly used early in the hit generation process, including a thermal shift assay (TSA), affinity mass spectrometry, endogenous tryptophan fluorescence detection, an ATP-exclusion assay using a non-hydrolyzable ATP analogue, classical kinetic analysis to assess ATP-dependence and mechanism-of-inhibition, X-ray crystallography, and finally, cross-competition experiments with known inhibitors. Using the cumulative knowledge gained from these technologies throughout the hit generation, hit-to-lead, and lead optimization stages has enabled us to make informed decisions and resulted in identification of many potent ATP-independent inhibitors. The AKIP technology to date has produced at least one clinical candidate, ARQ 092, which potently inhibits AKT with a high degree of selectivity amongst the human kinome. Further examples of the application of these various technologies will be provided for a diverse range of kinases, including c-Met, FGFR, Ack, and TNIK.

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 2914. doi:1538-7445.AM2012-2914
Abstract 2916: Discovery of pyrazolimidazopyridine compounds as potent in vitro and in vivo anaplastic lymphoma kinase inhibitors
Authors: Saeh Jamal C. , Yang Bin , Peng Bo , Kamhi Victor , Harrison Rane , Rivard Caroline , Wu Allan , Drew Lisa , Russell Daniel J.
Published: August 2012

Translocations linking anaplastic lymphoma kinase (ALK) to multiple fusion partners were identified in anaplastic large cell lymphoma (ALCL), inflammatory myofibroblastic tumors, esophageal squamous cell carcinomas, neuroblastoma, and in non small cell lung cancer (NSCLC). This fusion leads to constitutive activation of ALK and has potent transforming activity. The recent approval of Crizotinib validated clinically the usefulness of treating EML4-ALK +ve patients with an Alk inhibitor. We report two novel series of compounds that potently inhibit ALK both in vitro and in vivo. Two series of pyrazolimidazolpyridine compounds, with good physical properties, were identified as part of our screening effort as potent ALK inhibitors in ALK enzyme assays. Subsequent testing of the mode of action of these compounds in Del cell lines containing NPM-ALK fusions demonstrated strong inhibition of phospho-ALK. In vivo, oral administration of 10 mg/kg of a pyrazolimidazopyridine compound in a Del xenograft model in SCID mice resulted in greater than 90% inhibition of phospho-ALK over 6 hours. In conclusion, we have identified two series of pyrazolimidazopyridine compounds as potent ALK inhibitors both in vitro and in vivo.

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 2916. doi:1538-7445.AM2012-2916
Abstract 2918: Estrogen receptor coactivator MED1 in mammary progenitor/stem cell determination and tamoxifen resistance of breast cancer
Authors: Zhang Xiaoting
Published: August 2012

Mediator has recently emerged as the central player to directly transduce signals from transcription factors to the transcription machinery. MED1 (also named TRAP220, DRIP205 and MED220) subunit of the Mediator complex has been shown to directly interact and mediate the transcription of nuclear receptors, in a ligand-dependent fashion, through two classical LxxLL motifs. We have recently generated MED1 LxxLL motifs mutant knockin mice and interestingly, found these mutations do not affect the overall survival and the development of most tissues. However, we did observe severe defects in pubertal mammary gland development of MED1-mutant mice. Consistent with this phenotype, expression of a number of known ERα-regulated genes was downregulated in MED1-mutant mammary epithelial cells and these genes could no longer respond to estrogen stimulation. Interestingly, along with the restricted expression of MED1 in luminal but not basal mammary epithelial cells, we observed a very significant increase in the luminal stem/progenitor cell population in the mammary glands of MED1 mutant mice. We have further crossed this MED1 mutant knockin mice with a MMTV-PyVT mouse model that produce mainly luminal type of mammary tumors. Our date indicate that, although MED1 mutations did not affect the time and number of tumors formed, it significantly impacted the tumor progression and cancer stem cell formation in this model. To further study the role of MED1 in human breast cancer, we examined MED1 protein expression by using human breast cancer tissue microarrays. Consistent with previously reports that MED1 coamplifies with HER2, we found MED1 protein expression level is correlated most strongly with HER2 status. Further study supports HER2 as a major upstream regulator responsible for MED1 phosphorylation at sites known to be critical for MED1 activation. Interestingly, we found an increased recruitment of phosphorylated MED1 but not corepressors SMRT or NcoR to endogenous ER target genes’ promoter by tamoxifen in HER2-overexpressing cells. Importantly, knockdown of MED1 significantly sensitized the otherwise resistant HER2 overexpressing cells to the tamoxifen treatment. These results support MED1 as a key convergence point between ER and HER2 signaling pathways in mediating endocrine resistance. In summary, our studies revealed new roles of MED1 in mediating ER functions in both mammary stem/progenitor cell determination and tamoxifen resistance of breast cancer, and support potential use of MED1 as a tissue-specific therapeutic target for the treatment of human breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2918. doi:1538-7445.AM2012-2918
Abstract 2922: Androgen receptor driven transcription in a subtype of estrogen receptor negative breast cancer is controlled by FoxA1
Authors: Robinson Jessica L. , Brown Gordon D. , Neal David E. , Tilley Wayne D. , Carroll Jason S.
Published: August 2012

Breast cancer is a heterogeneous disease and several distinct subtypes exist based on differential gene expression patterns. Molecular apocrine tumors were recently identified as an additional subgroup, characterised as ERα- AR+, but with an expression profile that resembles ERα+ luminal breast cancer. Previously, we mapped global AR binding events in a cell line model of molecular apocrine breast cancer (termed MDA-MB-453 cells) using ChIP-seq. Our results suggested that these tumours are driven by AR through its interaction with critical ER cis-regulatory elements, resulting in a transcriptional programme reminiscent of ER-mediated transcription in luminal breast cancers. Additionally, we found that AR binding is a near-perfect subset of FoxA1 binding regions, a level of concordance never previously seen with a Nuclear Receptor. By silencing FoxA1 using specific siRNA, we observe dramatic changes in the gene expression profile of the cells (730 genes are differentially expressed) including many of the signature molecular apocrine genes. Furthermore, silencing of FoxA1 in these breast cancer cells results in altered AR binding to the chromatin (lost, conserved and de novo binding events are found) as has been previously seen in the prostate cancer cell line, LNCaP. We are investigating this phenomenon further using proteomics to discover new AR interacting proteins and histone mark ChIP-seq to understand the proteins and epigenetic events that may mediate the reprogrammed AR binding in the absence of FoxA1.

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 2922. doi:1538-7445.AM2012-2922
Abstract 2923: Androgen receptor activation changes chromatin structure and transcriptional activation
Authors: Tewari Alok K. , Yardimci Galip G. , Crawford Gregory E. , Febbo Phillip G.
Published: August 2012

Epigenetic mechanisms such as chromatin accessibility and histone modifications impact transcription factor binding to DNA and transcriptional specificity. The androgen receptor (AR), a master regulator of prostate cancer initiation and progression, acts primarily through ligand-activated transcription of target genes. By combining deep sequencing with DNase I hypersensitivity analysis (DNase-seq) and RNA analysis (RNA-seq) we assessed genome-wide chromatin structure and transcription and combined this data with publicly available AR chromatin immunoprecipitation data (AR Chip-seq). We find that 64% of DNase I hypersensitive sites (DHS) overlap each other before and after androgen in LNCaP cells. Interestingly, in regions with increased chromatin accessibility following androgen induction, the canonical AR DNA recognition motif is enriched. Comparing identified DHS to AR binding sites from three different data sets consistently reveals that 50% of AR binding overlaps a DHS in induced cells. Of those sites with both DHS and AR binding, approximately half are available prior to androgen induction (i.e. “primed”) and half open in response to androgen stimulation. This contrasts with the glucocorticoid receptor (GR), which was recently reported to bind to DNA primarily in regions that are accessible to nuclease cleavage prior to ligand activation. Our RNA-seq analysis discovered 367 genes regulated by AR activation (FDR < 0.05), including 16 of the 19 most commonly identified AR-mediated genes in several other studies. Importantly, we find that regions of increased chromatin accessibility are significantly associated with genes identified as AR-regulated by RNA-seq. Finally, base pair resolution of the DNase-seq signal reveals distinct footprinting patterns associated with the AR-DNA interaction. Analysis of chromatin structure, AR binding, and transcription prior to and following androgen induction demonstrates that AR activation by ligand induces genome-wide changes in chromatin accessibility, these changes correspond to AR binding to the genome, and they impact AR-mediated transcriptional response. These findings suggest that interaction between the AR and DNA alters chromatin structure and transcriptional specificity.

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 2923. doi:1538-7445.AM2012-2923
Abstract 2929: Predictors of survival in never-smokers with non-small cell lung cancer: A large-scale, two-phase genetic study
Authors: Pu Xia , Ye Yuanqing , Spitz Margaret R. , Wang Liang , Gu Jian , Lippman Scott M. , Hildebrandt Michelle AT , Hong Waun K. , Minna John D. , Roth Jack A. , Yang Ping , Wu Xifeng
Published: August 2012

Lung cancer in never-smokers is increasingly recognized as distinct from that in ever-smokers owing to substantial differences in etiology, clinical characteristics, and prognosis. Therefore, we aimed to identify prognostic markers specific for lung cancer in never-smokers in a two-stage study. First, 11,930 single-nucleotide polymorphisms (SNPs) in 904 inflammation-related genes were genotyped, and their associations with overall survival in 411 never-smokers with lung cancer at The University of Texas MD Anderson Cancer Center were analyzed. Next, fast-track validation of the top 37 SNPs in 311 never-smokers with lung cancer at Mayo Clinic was performed. Three SNPs (interleukin 17 receptor A:rs879576, bone morphogenetic protein 8A:rs698141, and spleen tyrosine kinase:rs290229) were validated (p<0.05), and two more SNPs (CD74:rs1056400 and CD38:rs10805347) were borderline significant (p=0.08) in the Mayo Clinic population. In combined analysis of the MD Anderson and Mayo Clinic patients, IL17RA:rs879576 resulted in a 40% reduction in the risk of death (p=4.1 × 10−5 [p=0.61, heterogeneity test]). We successfully validated a survival tree created in MD Anderson population based on gene-gene interactions in the Mayo Clinic population. This survival tree stratified patients into subsets with significantly different risks of death: patients at MD Anderson with the rs1056400_GG/rs698141_GA+AA genotype had a 2.32-fold higher risk of death (p=1.72 × 10−5) and 9-month shorter median survival time (MST) (p=4.5 × 10−4, log-rank test) than did those with the rs1056400_GG/rs698141_GG or rs1056400_GA+AA genotype in the discovery phase. Also, the patients at Mayo Clinic with the former genotype had an approximately twofold higher risk of death (p=0.02) and a strikingly shorter (by 26 months) MST (p=0.029, log-rank test) than did those with the latter genotype in the validation phase. We evaluated these five SNPs in 996 ever-smokers and found no significant associations. To our knowledge, this is the first study to systematically evaluate the associations of genetic variations in major inflammation-related genes with outcome of lung cancer in never-smokers. It provides strong evidence that inflammation-related genetic variations can affect clinical outcomes in these patients, which may lead to significant biological insight into these outcomes.

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 2929. doi:1538-7445.AM2012-2929
Abstract 293: Tumor cell cross-talk with tumor-associated leukocytes leads to induction of tumor exosomal fibronectin and promotes tumor progression
Authors: Zhang Huang-Ge , Deng ZhongBin
Published: August 2012

Exosomes play an important role in intercellular communication. However, most data published are based on exosomes released from in vitro cultured cells that do not exhibit communication with neighboring cells located in the same microenvironment as the exosomal producing cells, and therefore in vitro culture experiments do not represent what occurs in vivo. In this study, our data show that co-culture of leukocytes isolated from breast tumor tissue leads to uptake of fibronectin on/in the tumor exosomes (Exofib+). The induction of fibronectin and exosomal uptake is tumor tissue derived, leukocyte specific, as leukocytes isolated from peripheral blood of naïve mice failed to induce fibronectin uptaken by tumor exosomes. Furthermore, depletion of both CD25+ cells and Gr-1+ cells from tumor-associated leukocytes causes a reduction of Exofib+ suggesting that tumor-associated CD25+ cells and Gr-1+ cells play a role in fibronectin production and uptake by tumor exosomes resulting in Exofib+. As a result of tumor cells taking up Exofib+ two major events are induced: FAK/Src-dependent signaling pathways are activated, and the production of proinflammatory cytokines and metalloproteinase 9 is enhanced in response to taking up exosomes and this in turn enhances tumor cell invasion in vitro as well as in vivo. Collectively, our findings provide evidence that exosomes released from freshly excised tumor tissue cells that have communicated/interacted with immune cells gain new immune evasion capacity.

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 293. doi:1538-7445.AM2012-293
Abstract 2932: Knockdown of polypyrimidine tract-binding protein (PTB) sensitizes ovarian cancer cells to chemotherapeutic agents in vitro
Authors: Arslan Ahmet D. , Maggio Matthew , El-Shennawy Lamiaa , He Xiaolong , Beck William T.
Published: August 2012

While chemotherapy is the second-line of therapy for the treatment of epithelial ovarian cancer (EOC) after surgery, drug resistance constitutes a significant obstacle to achieving a complete response in many patients. There is a clear unmet need for new treatments for EOC patients. We have shown that PTB is frequently overexpressed and associated with malignancy in EOC (He et al, Clin Cancer Res, 10:4652-60, 2004, He et al, Oncogene 30:356-65, 2011). PTB knockdown via RNA interference significantly impairs EOC cell growth in vitro and in vivo, as well as invasiveness and colony formation in soft agar in vitro (He et al, Oncogene 26:4961-8, 2007). PTB or hnRNP-I is a splicing factor that regulates alternative pre-mRNA splicing, and has been implicated in metabolic, cytoskeletal, and cell membrane changes in cancer cells. In this study, we used A2780 cell lines carrying doxycycline (doxy)-inducible PTB shRNA. We characterized stable transfectants of A2780 cells that carry shRNA against PTB and cells carry a non-targeting control shRNA. In a 48 h MTT cytotoxicity assay, knockdown of PTB inhibited cell growth. When cells with PTB knockdown were treated with carboplatin or paclitaxel, drugs used as current standard of care in EOC, we observed 3- to 6-fold increases in drug sensitivity compared to the vector control. To rule out any drug-drug interaction (e.g., doxy-paclitaxel) (Foroodi et al, Anticancer Drugs 2009 20:115-22) in our assay, we evaluated the kinetics of the inducible knockdown system by western blot. We found that a 120 h doxy treatment was optimal to insure full depletion of PTB, and after doxy removal PTB suppression lasted 48 h more before recovering to its basal level. Based on those data, we performed all the cytotoxicity experiments within 48 h without exposing cells to both doxy and drug at once, and thereby avoiding drug-drug interactions. Findings here support the idea that PTB and other splicing factors may be novel drug targets in the treatment of ovarian cancer. (Support in part by NCI grants R01 CA40570 and R01 CA138762 [to WTB], by OCRF [to XH], and by UIC.)

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 2932. doi:1538-7445.AM2012-2932
Abstract 2933: Synthetic lethal screening: A pathway for rational combinatorial therapies for cancer
Authors: Axelrod Mark J. , Gioeli Daniel G. , Weber Michael J.
Published: August 2012

We hypothesize that many cases of both intrinsic and acquired resistance to single agent targeted cancer drugs occur due to the activation of compensatory signaling pathways. Combination therapies targeting both the primary and compensatory pathways may be able to produce more robust and durable responses. To identify these compensatory pathways and rationally construct combination therapies, we performed a synthetic lethal screen of 420 targeted small molecule inhibitor combinations on 17 cancer cell lines, yielding over 5500 combinatorial tests. We identified both novel and expected synergistic combinations. Among the expected combinations was the combination of inhibitors of EGF Receptor with inhibitors of PI3 Kinase. Because this combination is currently being evaluated in clinical trials, we have focused on examination of the cellular and molecular mechanism(s) of the synthetic lethality. We found that inhibition of PI3 Kinase led to increased ERK activation, and conversely that inhibition of MEK resulted in increased signaling through the PI3 Kinase pathway. Flow cytometric analysis revealed that this synergistic cytotoxicity is both due to a robust apoptotic response to combination treatment measured by caspase 3 cleavage and also a decrease in proliferation upon combination treatment measured by BrdU incorporation. Using Reverse Phase Protein Arrays, we identified phosphorylation of ribosomal protein S6 as a molecular biomarker of synergistic cytotoxicity with these agents. To determine whether this biomarker reflects a mechanistic node in the signaling network, we tested pharmacological inhibition of 70 kD ribosomal protein S6 kinase (p70S6K) and found only modest cytotoxicity, but also robust activation of ERK1 and 2. This increase could be blocked by the addition of a pharmacological inhibitor of the EGF Receptor, suggesting a negative feedback loop between p70S6K and the EGF Receptor. Combined treatment with p70S6K and EGF Receptor inhibitors resulted in synergistic cytotoxicity. Currently, we are identifying the node between EGF Receptor and p70S6K signaling that could be responsible for this synthetic lethality. Additionally, we are conducting xenograft studies using inhibitors of this pathway that are currently in clinical trials, to test the efficacy of this drug combination in vivo.

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 2933. doi:1538-7445.AM2012-2933
Abstract 2939: Discovery and synthesis of highly potent and selective small molecule inhibitors of the histone methyltransferase EZH2
Authors: Verma Sharad K. , LaFrance Louis V. , Tian Xinrong , Newlander Ken , Duquenne Céline , Suarez Dominic , Knight Steven D. , Burgess Joelle , Brackley James , Johnson Neil W. , Graves Alan P. , Mellinger Mark , Romeril Stuart , Grant Seth W. , Scherzer Daryl , Shu Art , Creasy Caretha L. , Kruger Ryan , Diaz Elsie , Le Baochau , Thompson Christine , Morgan-Ott Heidi , McCabe Michael T. , McHugh Charles F. , Miller William H. , Tummino Peter , Dhanak Dash
Published: August 2012

The histone methyltransferases are a group of enzymes which catalyze the transfer of a methyl group from the co-factor S-Adenosylmethionine (SAM) to the lysine and arginine residues of histone tails. This post-translational modification is a key event in maintaining gene expression patterns. In recent years, the relationships between aberrant histone methylation patterns and cancer progression have been recognized. These developments, along with an improved understanding of the underlying structural biology, have made histone methyltransferases highly attractive targets for therapeutic intervention. The histone lysine methyltransferase EZH2 (Enhancer of Zeste Homolog 2) is frequently over-expressed in a wide variety of cancerous tissues. There is a strong correlation between overexpression of EZH2 and aberrant transcriptional signaling in cells, ultimately resulting in poor clinical prognosis. Inhibition of EZH2 is expected to alter transcriptional expression and ultimately lead to an improved clinical outcome. This presentation will describe medicinal chemistry efforts in the development of highly potent and selective small molecule inhibitors of EZH2. The synthesis, SAR, and identification of a clinical candidate will be discussed.

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 2939. doi:1538-7445.AM2012-2939