bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A34: Analysis of gossypol-induced cytotoxicity in malignant peripheral nerve sheath tumor cells.
Authors: Kaza Niroop , Roth Kevin A.
Published: June 2012

Malignant peripheral nerve sheath tumors (MPNSTs) are highly aggressive Schwann cell-derived sarcomas. MPNSTs are the leading cause of mortality in patients with neurofibromatosis type 1 (NF1), an autosomal dominant genetic disease. Current treatment modalities have been ineffective resulting in high recurrence (40–68%) and poor five year survival rate between 16–52% in these tumors. This necessitates the need for novel therapeutic options. The anti-apoptotic members of the Bcl-2 family have been reported to be over expressed in a variety of cancers and have been implicated in rendering cancer cells resistant to apoptosis. Gossypol, a naturally occurring phenolic compound, functions as a BH3 mimetic by occupying the BH3-binding groove of anti-apoptotic proteins of the Bcl-2 family. Gossypol has been shown to induce cell death in prostate cancer, breast cancer, glioma and some hematological cancer cell lines. In this study, we assessed the effect of AT101 (gossypol) on MPNST cells. We observed that AT101 caused a dose and time dependent decrease in viability in MPNST cells which was not accompanied by an increase in caspase activation. AT101 also caused accumulation of autophagic vacuoles. Blocking the initiation of autophagy attenuated the cell death caused by AT101, while blocking apoptosis did not provide any protection. In summary, AT101 induces autophagic vacuole accumulation leading to cell death independent of caspase activation in MPNST cells. Further studies are needed to elucidate the mechanisms through which AT101 causes cell death in MPNSTs.

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 A34.
Abstract A35: DNA microarray analysis of the effect of fusarochromanone on human malignant bladder cancer cells.
Authors: King Trey , Key Mickeal , Clifford John , Gill Jennifer Roberts , Kim Yoonjee , Mahdavian Elahe , Cvek Urska , Salvatore Brian , Furmanski Brian , Rhoads Robert , Williams-Hart Tara
Published: June 2012

Fusarochromanone (FC-101a) has been identified as a potential, novel anti-cancer compound. Several studies revealed that FC-101a is an inhibitor of many human cancer cell lines, increases apoptosis of melanoma cell lines and significantly reduces tumor growth in mice. The long-term goal of this project is to elucidate how FC-101a inhibits cancer cell growth by identifying its molecular target(s). In this study, we used DNA microarray analysis and realtime PCR to identify genes that are differentially-expressed in response to FC-101a treatment in yeast and human bladder cancer cells. We hypothesize that changes in gene expression in response to FC-101a treatment will elucidate cellular mechanisms by which FC-101a inhibits cancer cell growth. Our study includes human cancer cell lines as a model system and budding yeast as a model organism to identify cellular pathways that are responsive to FC-101a treatment in multiple eukaryotic cell types. In this study, we have determined that among human skin, breast, prostate and bladder cancer cell lines, bladder cancer cells are the most sensitive to FC-101a treatment. Thus, we performed DNA microarray analysis using human bladder carcinoma cells treated with FC-101a for 24, 48 and 72 hours and yeast cells treated with FC-101a for 20 minutes. We identified hundreds of genes that are highly expressed and greater than two-fold up-regulated or down-regulated in FC-101a-treated cells compared with untreated cells. Of these FC-101a-responsive genes common to yeast and human bladder cancer cells, a majority of these genes regulate apoptosis, metabolic pathways, cell cycle progression, DNA replication, cell signaling and DNA recombination and repair.

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 A35.
Abstract A48: Osteopontin increases heme oxygenase-1 expression and subsequently induces cell migration in glioma cells.
Authors: Lu Dah-Yuu , Yeh Wei-Lan , Chou Shao-Jiun
Published: June 2012

Malignant gliomas are the most common primary brain tumors in adults and the second most common tumor in children. Gliomas are associated high morbidity and mortality because these tumors are highly invasive into surrounding brain tissue, making complete surgical resection impossible. Glial cell line-derived neurotrophic factor (GDNF) has been identified as a potent neurotrophic factor in a variety of neuronal cell populations. However, the molecular mechanisms and pathologic roles underlying GDNF-induced glioma migration remain unclear. In this study, we found that application of recombinant human GDNF enhances the migration of U87 and U251 cells but not C6 cells. In addition, we found that the expression of matrix metalloproteinase-13 (MMP-13) mRNA, protein and secretion increase in response to GDNF stimulation. The GDNF-induced increase in cell migration was antagonized by MMP-13 neutralizing antibody or silencing MMP-13. We then examined the involvement of mitogen-activated protein kinases (MAPKs) in glioma cell migration induced by GDNF. GDNF-induced MMP-13 expression and glioma migration were attenuated by MEK/ extracellular signal-regulating kinase (ERK) and c-Jun N-terminal protein kinase (JNK) inhibitors, as well as ERK and JNK dominant-negative mutants. Treatment with GDNF induced MEK/ERK and JNK/c-Jun activation and increased AP-1 DNA binding activity in a time-dependent manner. Treatment with AP-1 inhibitors (tanshinone IIA and curcumin) also reduced GDNF-induced glioma cell migration. In migration-prone sublines, cells with greater migration ability had higher GDNF expression. These results indicate that GDNF enhances migration of glioma cells through the increase of MMP-13 production and is mainly regulated by the MEK/ERK and JNK, c-Jun and AP-1 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 A48.
Abstract A54: Mithramycin inhibits cigarette smoke-mediated induction of ABCG2 in lung and esophageal cancer cells: Implications for targeting cancer stem cells in thoracic malignancies.
Authors: Zhang Mary , Mathur Aarti , Rao Mahadev , Xi Sichuan , Zhang Yuwei , Datrice Nicole , Hong Julie A. , Kemp Clinton D. , Ripley R. Taylor , Atay Scott , Weigand Gordon , Avital Itzak , Li Xinmin , Schrump David S.
Published: June 2012

Limited information is available regarding epigenetic mechanisms by which cigarette smoke mediates initiation and progression of thoracic malignancies. In order to examine this issue, lung and esophageal cancer cells (A549, Calu-6, NCI-SB-ESC1 and NCI-SB-ESC2), were cultured in normal media (NM) with or without cigarette smoke condensate (CSC) under clinically relevant exposure conditions. Microarray analysis revealed that five day CSC exposure significantly up-regulated ABCG2, encoding a xenobiotic pump highly expressed in cancer stem cells. Quantitative reverse transcription-PCR (qRT-PCR), western blot, and immunohistochemistry experiments confirmed up-regulation of ABCG2 in cultured cancer lines, but not normal small airway epithelial cells (SAEC) or immortalized esophageal squamous cells (HET1A) exposed to CSC. Flow cytometry experiments demonstrated that CSC increased the side population (SP) of cultured cancer cells. Transient transfection experiments using ABCG2 promoter reporter constructs revealed that deletion of xenobiotic response elements as well as SP-1 sites markedly attenuated ABCG2 induction by CSC. Chromatin immunoprecipitation (ChIP) experiments revealed that CSC-mediated induction of ABCG2 coincided with increased occupancy of aryl hydrocarbon receptor (AHR), SP-1, and Nrf2, as well as increased levels of RNA pol II and H3K9Ac within the ABCG2 promoter. Under conditions potentially achievable in clinical settings, mithramycin diminished basal as well as CSC-mediated increases in AHR, SP-1, and Nrf2 levels within the ABCG2 promoter, down-regulated ABCG2 expression, decreased S P, inhibited in-vitro proliferation of lung and esophageal cancer cells, and markedly diminished growth of established tumor xenografts. Microarray analysis revealed significant down-regulation of numerous stem-cell related pathways in lung cancer cells following mithramycin exposure. Collectively, these findings provide a potential mechanistic link between smoking status and outcome of patients with lung and esophageal cancers, and support clinical evaluation of mithramycin for targeting cancer stem cells in thoracic malignancies.

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 A54.
Abstract A62: Monensin-induced oxidative stress reduces prostate cancer cell motility and cancer stem cell markers.
Authors: Ketola Kirsi , Vuoristo Anu , Oresic Matej , Kallioniemi Olli , Iljin Kristiina
Published: June 2012

Therapeutic options for prostate cancer are limited and treatment responses to currently existing therapies are often unsatisfactory. Thus, there is an urgent need for novel agents to target advanced and metastatic prostate cancer cells. We have recently carried out a chemical-biological high-throughput screening of 4,910 known drugs and drug-like molecules in four prostate cancer cell models and two non-tumorigenic prostate epithelial cell lines to identify prostate cancer cell growth selective inhibitors. Only four compounds, antibiotic ionophore monensin, aldehyde dehydrogenase (ALDH) inhibitor disulfiram, histone deacetylase inhibitor trichostatin A and fungicide thiram inhibited selectively cancer cell growth at nanomolar concentrations. The mechanistic studies indicated that monensin inhibited prostate cancer cell growth by inducing oxidative stress and apoptosis. In addition, monensin reduced androgen receptor signaling, showed a synergistic anti-proliferative effect with anti-androgens as well as reduced the levels of MYC and ERG oncogenes and reduced the activity of ALDH in prostate cancer cells. Moreover, antioxidant vitamin C rescued the monensin induced growth inhibition, indicating that oxidative stress plays a key role in the antineoplastic effect of monensin in cultured prostate cancer cells.

Our previous Connectivity Map results indicated that monensin has agonistic effects to NF-κB inactivator and oxidative stress inducer niclosamide. Here, we show that monensin indeed reduced the activity of NF-κB pathway. NF-κB maintains cellular antioxidant defence capacity and its inhibition induces oxidative stress as well as reduces tumorigenesis, metastasis and cancer stem cell potential. Cancer stem cells have a controlled redox balance system including high ALDH and CD44 expression which protect cancer stem cells from oxidative stress. Our results confirmed that monensin reduced the cancer stem cell markers in prostate cancer cells. Moreover, monensin induced epithelial cell differentiation shown as well as reduced motility in cultured prostate cancer cells, suggesting that monensin inhibits prostate tumorigenesis by multiple ways. Furthermore, the steroid profiling indicated that monensin increases the levels of oxidative stress inducing steroids and reduces androgen precursors in cultured prostate cancer cells. In conclusion, our results suggest that impairing the redox control, which has a crucial role in cancer cells enabling survival under high intracellular ROS, is a potent way to target prostate cancer cells and potentially also prostate cancer stem cells.

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 A62.
Abstract A76: MDV3100, a novel androgen receptor signaling inhibitor, promotes cell apoptosis and tumor regression in both in vitro and in vivo models of castration-resistant prostate cancer.
Authors: Bernales Sebastian , Guerrero Javier , Gomez Francisco , Alfaro Ivan E. , Iguchi Kanako , Kusayama Toshiyuki , Protter Andrew A.
Published: June 2012

Prostate tumors initially respond to androgen deprivation therapy but eventually progress despite low serum levels of testosterone. In this stage, known as castration-resistant prostate cancer (CRPC), abnormal androgen receptor (AR) signaling persists and classic anti-androgens such as bicalutamide are ineffective at controlling tumor growth. The novel AR signaling inhibitor MDV3100 has been demonstrated to inhibit AR signaling in preclinical models of CRPC. Here, we investigate further the cellular effects of MDV3100 treatment on AR signaling in in vitro models and in vivo xenograft models of CRPC.

Our experiments reveal that MDV3100 (> 100 nM) inhibits dihydrotestosterone (DHT) induced AR-target gene expression in LNCaP cells and LNCaP/AR cells, a CRPC cell culture model in which AR is over-expressed. Inhibition of Prostate-Specific Antigen mRNA expression by MDV3100 was effective at concentrations 10-fold lower than with bicalutamide. As evidenced in other studies and in contrast to bicalutamide, MDV3100 did not display agonistic effects on AR signaling at 10 μM. In contrast to bicalutamide, MDV3100 (> 1 μM) inhibited androgen dependent nuclear translocation of AR, as measured with a quantitative optical based enzyme fragment complementation assay and AR-YFP localization in HEK-293 cells. Furthermore, in the presence of DHT, MDV3100 effectively reduced cell viability of LNCaP cells at concentrations as low as 0.1 μM, 10-fold lower than bicalutamide. MDV3100 also decreased cell viability of LNCaP/AR and W741C-LNcaP cells. We found that the apoptosis marker cleaved-caspase 3 was induced in LNCaP/AR cells treated with 1 M MDV3100 for 48 hours. Under these conditions, MDV3100 was more potent than bicalutamide in decreasing cell viability. Finally, we show that MDV3100 inhibited tumor growth and induced regression of tumor volume in a xenograft model of CRPC generated with LNCaP/AR cells.

These results demonstrate that MDV3100, unlike anti-androgens, is effective in both in vitro and in vivo models of CRPC and that its mechanistic advantages over other anti-androgens could be explained by its ability to inhibit AR nuclear translocation and induce cell death.

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 A76.
Abstract A77: Efficacy of PARP inhibitor AG014699 in orthotopic GBM xenografts is limited by ineffective drug penetration into the central nervous system.
Authors: Cen Ling , Carlson Brett L. , Schroeder Mark A. , Murray James , Sludden Julieann , Boddy Alan V. , Curtin Nicola J. , Sarkaria Jann
Published: June 2012

Poly (ADP-ribose) polymerase (PARP) inhibition can enhance the efficacy of temozolomide (TMZ) and has been shown to significantly prolong survival in orthotopic GBM xenografts. Here the effects of PARP inhibitor AG014699 (AG699) on the efficacy of TMZ was evaluated and corresponding pharmacokinetic and pharmacodynamic studies were performed in the MGMT methylated GBM12 primary GBM xenograft line. AG699 effectively sensitized GBM12 cells to TMZ in vitro in a neurosphere formation assay: IC50 of 1.56 M for TMZ when combined with 1 μM AG699 compared to 8.16 M TMZ when used alone). Using these same cells, orthotopic xenografts were established and mice were randomized to 3–28 day cycles of placebo or TMZ (50 mg/kg days 1–5) with or without AG699 (1 mg/kg IP days 1–5). Although this model is responsive to other TMZ/PARP inhibitor combinations, the addition of AG699 was ineffective (median survival: placebo 16 days, TMZ 68 days and TMZ/AG699 81 days, p=0.883). In contrast, AG699 significantly potentiated TMZ-induced tumor regrowth delay in a flank tumor model with GBM12 (median time for tumors to reach endpoint: placebo 32 days, TMZ 86 days and TMZ/AG699 121 days, p<0.01). To more clearly understand the discrepancy between intracranial and flank studies, drug accumulation and target inhibition were assessed. Plasma and tissue distribution studies in mice bearing GBM12 orthotopic xenografts showed that 0.5 h after AG699 treatment its level in brain and tumor xenograft was much lower compared with that in liver (see table). In an assessment of catalytic activity, PARP activity in liver was inhibited more than 95% of control at least 2 h after AG699 treatment, while it was inhibited less than 50% and 30% in orthotopic xenograft tissue and normal brain, respectively (Table). Collectively, these data support the hypothesis that the efficacy of AG699 combined with TMZ is limited in the orthotopic model due to limited drug accumulation within the brain, and the mechanisms of which are under investigation.

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 A77.
Abstract A86: A phase 1 study of LY2523355, an Eg5 inhibitor, administered on Days 1, 2, and 3 with or without pegfilgrastim in patients with advanced malignancy (NCT01214629).
Authors: Verschraegen Claire , Cohen Roger B. , Olszanski Anthony J. , Shaheen Montaser , Nishida Yuko , Bauman Julie , Li Lily , Brandt John T. , Nasir Aejaz , Hynes Scott M. , Leohr Jennifer K. , McGlothlin Anna , Westin Eric H.
Published: June 2012

Background: LY2523355 is a potent allosteric inhibitor of the motor protein Eg5 which selectively inhibits bipolar mitotic spindle formation. The objective of this Phase 1 study was to determine a Phase 2 dose and schedule of LY2523355 that may be safely administered to patients with advanced malignancy.

Methods: Study I1Y-MC-JFBA is an open-label, multicenter, dose-escalation study in patients with advanced malignancy. A modified 3+3 dose-escalation scheme was used, followed by a dose confirmation phase with pre- and post-treatment tumor biopsies. Patients received LY2523355 as a 1hr infusion on days 1, 2 and 3 of a 21-day cycle with determination of the MTD with and without pegfilgrastim administration on day 4. Patients were assessed every other cycle by RECIST. Treatment related PD changes in phosphohistone H3 (pHH3) and Eg5 expression were assessed in skin and tumor biopsies by immunohistochemistry.

Results: 46 patients were enrolled in the study as of October 2010. The most frequent related AEs reported (>10%) include leukopenia, neutropenia, fatigue, nausea, stomatitis, vomiting, alopecia, anemia, diarrhea, lymphopenia, pruritis/itching and rash. Dose-limiting toxicities include increased INR, leukopenia, diarrhea, rash (palmar plantar erythrodysesthesia), febrile neutropenia, and mucositis. The single and multiple dose pharmacokinetics of LY2523355 and metabolite were characterized. Dose dependent increase in LY2523355 plasma exposure and a minor degree of intra- and inter-cycle accumulation were observed. An exposure-dependent increase in pHH3 and Eg5 expression and increase in apoptotic cells in tumor and skin biopsies has been demonstrated. One patient with ovarian cancer had a confirmed partial response. Nine other patients had stable disease for at least 2 cycles.

Conclusions: The MTD of LY2523355 for this schedule has been established with and without pegfilgrastim at 6mg/m2/d and 4 mg/m2/d, respectively. These doses have shown a quantifiable PD response in skin and tumor biopsies confirming the importance of maximizing exposure intensity for maximum PD response. Dose confirmation is on-going.

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 A86.
Abstract B10: Diversity Outbred: A new, highly diverse mouse stock for toxicology and cancer.
Authors: Schile Andrew , Svenson Karen L. , Fancher Karen S. , Valdar William , Chesler Elissa J. , Churchill Gary A.
Published: June 2012

The Diversity Outbred (J:DO) stock is a new heterogeneous, highly diverse mouse resource designed for complex trait analysis and toxicology studies as well as to facilitate rapid mapping with single gene resolution. This stock was derived from crossing partially-inbred Collaborative Cross strains, which are a mixture of eight genetically well-defined JAX® Mice inbred strains, including three wild-derived. Subsequent maintenance follows a randomized outcross non-sibling mating scheme to retain maximum genetic diversity. Each Diversity Outbred mouse is genetically unique, representing a novel combination of alleles present in the founder strains. To determine the extent to which this genetic variation leads to phenotypic variation, over 50 metabolic measurements including plasma glucose, insulin, triglycerides, cholesterol, and body composition were collected, under both standard chow and high fat diet conditions. The Diversity Outbred animals displayed a wide spectrum of metabolic phenotypes, home cage nesting behavior and aggressiveness. Mouse-to-mouse variation is demonstrated by fold-differences in plasma triglycerides and creatine kinase levels, both as high as 11–12. Plasma glucose, free fatty acids, thyroxine, and percentage of fat all showed differences of 3-fold or greater. These fold-changes are comparable to the variation among unique inbred mouse strains, and mimic the diversity within human populations. The J:DO stock represents a new powerful tool for rapid gene mapping, toxicology/pharmacogenomic screens and compound evaluation for a wide variety of human diseases, including cancer and metabolic diseases.

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 B10.
Abstract B102: 19-Substituted benzoquinone ansamycins: Decreasing the toxicity of the benzoquinone ansamycin class of Hsp90 inhibitors.
Authors: Chang Chuan-Hsin , Kitson Russell , Reigan Philip , Siegel David , Moody Christopher J. , Ross David
Published: June 2012

Benzoquinone ansamycins (BQAs) were the first class of Hsp90 inhibitors developed but members of this class, particularly geldanamycin, demonstrated hepatic toxicity. One major mechanism of toxicity of the BQA class is manifested via the electrophilic properties of the quinone and arylation of cellular nucleophiles at the 19-position of the ansamycin ring. Using selective halogenation and palladium-catalyzed coupling, we have synthesized a number of novel 19-substituted BQAs in the geldanamycin, 17-AAG and 17-DMAG series as a means to prevent arylation of cellular nucleophiles and have validated this approach using model thiols including N-acetylcysteine and glutathione. 19-Substituted BQAs did not react with thiols at the 19-position while marked reactivity could be detected using their parent quinones. 19-Substituted BQAs were tested for their ability to inhibit recombinant yeast Hsp90 and 19-substitution did not block the capacity of these novel molecules to inhibit the ATPase activity of the Hsp90 chaperone. This result was confirmed by molecular modeling of 19-substituted derivatives in the active site of human Hsp90 demonstrating that 19-substitution did not block entry of the molecule into the active site. The addition of NAD(P)H:quinone oxidoreductase 1 (NQO1) potentiated inhibition of recombinant yeast Hsp90 by 19-substituted BQAs confirming our previous data demonstrating increased inhibitory efficacy of the hydroquinone ansamycin relative to its parent quinone. Cellular effects of 19-substituted BQAs were examined in MDA468 breast cancer cells and the isogenic MDA468/NQ16 cell line which over-expresses NQO1. Growth inhibitory effects were observed using 19-substituted BQAs and were potentiated by the presence of NQO1 in the MDA468/NQ16 line. Hsp90 inhibition in MDA468 and MDA468/NQ16 cells was confirmed using decreases in the Hsp90 client protein Raf1 and a compensatory increase in Hsp70 as biomarkers. In summary, these data demonstrate that 19-substituted BQAs do not react with thiols at the 19-position but retain their Hsp90 inhibitory capacity using purified enzyme and in cells suggesting that they should undergo further translational evaluation as therapeutic candidates (Supported by CA51210 and the Parkinsons Disease Society UK).

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 B102.
Abstract B104: Tid1 as a novel target for HSP-directed therapy in NSCLC.
Authors: Chen Chi-Yuan , Jan Chia-Ing , Lo Jeng-Fan , Hong Tse-Ming , Yang Pan-Chyr
Published: June 2012

Molecular chaperones, commonly known as heat shock proteins (HSPs), are essential for mammalian cells to maintain homeostasis. HSPs may interact with diverse co-chaperones and induce an ATPase-coupled structural change in client proteins and regulate critical signaling networks. More than 200 client proteins have been identified which may serve as important therapeutic targets in human diseases. The human tumorous imaginal disc 1 (Tid1) protein, a member of the DnaJ domain protein family, is a tumor suppressor and is known to promote ubiquitin-mediated degradation of oncogenic kinases. The Tid1 is a heat shock protein and function as molecular chaperone. In this work, we investigated the role of Tid1 in the tumorigenesis of non-small-cell lung cancer (NSCLC). The expression of two alternatively spliced isoforms of Tid1 (Tid1L and Tid1S) as well as EGFR was examined with RT-PCR and immunohistochemistry (IHC) in tumors from NSCLC patients. The expression of Tid1 was reduced in the majority of NSCLCs and an inverse correlation was observed for the expression of Tid1 and EGFR. Furthermore, we demonstrated that Tid1L, EGFR, HSP70, and HSP90 interacted with each other, and this interaction is dependent on functional DnaJ domain of the Tid1L. Overexpression of the Tid1L in lung cancer cells in vitro inhibited cell proliferation, anchorage-independent growth, and induced apoptosis. We further showed that overexpression of the Tid1L in lung cancer cells attenuated EGFR signaling activity and inhibited the activation of AKT, ERK and STAT3. In contrast, knockdown of Tid1 in EGFR-transfected lung cancer cells markedly increased the stability of EGFR. Taken together, our results support that Tid1L may play a critical role in regulating EGFR signaling in NSCLC; raising the possibility that Tid1 may be a novel target for HSP directed therapy.

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 B104.
Abstract B107: Characterization of a small molecule selective androgen receptor downregulator: A novel approach for the treatment of castration-resistant prostate cancer.
Authors: Loddick Sarah A. , Brave Sandra , Campbell Hayley , Gaughan Luke , Growcott Jim , Lahan Natalie , Mouchet Elizabeth , O'Neill Daniel , Robson Craig , Shaheen Fadhel , Thomason Andrew , Trueman Dawn , Walker Graeme , Brooks Nigel
Published: June 2012

The androgen receptor (AR), an important molecular target in the aetiology and progression of prostate cancer, has been found recently to drive key signalling responses in castration resistant prostate cancer (CRPC) after classical androgen ablation therapies have failed. Here we describe the biological characterisation of a novel and selective small molecule AR downregulator and propose this mechanism as a potential new approach for the treatment of CRPC. The compound is a derivative of a novel AR binding core with selectivity over other nuclear hormone receptors, and causes a reduction of AR protein in human LNCaP prostate cancer cells in vitro. The reduction in AR protein is observed in steroid depleted serum (CSS) conditions and demonstrates a differential mode of action from a classical AR antagonist (bicalutamide) which has no effect on AR protein expression. This AR downregulation translates into functional activity in vitro and in vivo. In cell viability assays in vitro the compound has activity in cells expressing wild-type (VCaP) and mutated (T877A) AR, but is inactive in AR-negative PC3 and DU145 prostate cancer cells, indicating a dependency on AR for efficacy. We have also observed a reduction in PSA synthesis in vitro, consistent with the inhibition of AR signalling. The compound also reduced AR protein expression, PSA synthesis and cell viability in LNCaP-Casodex™-Resistant and LNCaP-Androgen-Independent cells in vitro. We investigated in vivo activity using the Hershberger castrated rat assay where oral dosing (100mg/kg twice-daily for 7 days) resulted in a significant inhibition of testosterone-induced growth of sexual accessory organs. In summary we describe data supporting our hypothesis that a selective AR downregulator offers a novel approach for delivering therapeutic benefit in CRPC.

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 B107.
Abstract B135: Treatment with the MEK inhibitor PD0325901 modulates expression of key members of the MEK pathway in BRAFV600E but not BRAFWT thyroid cell lines.
Authors: Dorris Emma R. , Smyth Paul , O'Leary John J. , Sheils Orla
Published: June 2012

Introduction: The MEK/ERK pathway is mutated in approximately 7% of human cancers. Extracellular ligands signal via RAS to recruit RAF kinase and activate MEK and its downstream effectors. This pathway is involved in a range of biological pathways including cell proliferation, differentiation and senescence. The BRAF isoform is the most potent activator of MEK and is frequently mutated in cancer. A single thymine to adenine base pair change at position 1799 accounts for greater than 95% of somatic mutation in BRAF. BRAFV600E can gain 500-fold increased activation, stimulating the constitutive activation of the MEK/ERK pathway in the absence of extracellular signalling. The strategic position of MEK within the pathway makes it a promising target for drug development. Although MEK is downstream of both RAF and RAS, RAF but not RAS mutation has been demonstrated to predict sensitivity to MEK inhibition.

Materials and Methods: Human thyroid cell lines were SNP typed for the T1799A mutation using a custom TaqMan® SNP genotyping assay. The optimal IC50 and length of treatment for the MEK inhibitor PD0325901 for each cell line were determined via a series of MTT assays. Each cell line was subjected to PD0325901 treatment and surviving cells were harvested for mRNA and protein extraction. A comparative study for relative expression of MAP2K1 (MEK1), MAP2K2 (MEK2), MAPK3 (ERK1), MAPK1 (ERK2) and the downstream target ELK1 was performed using TaqMan assays with GAPDH as the endogenous control.

Results: Human thyroid cell line 8505c carries the T1799A mutation and N-Thy-Ori cell lines carry wild type BRAF. BRAFV600E cells had visually evident patches of inhibition following PD0325901 treatment which were not evident in media-only treated controls or in the BRAFWT cell line. In BRAFV600E, all 5 genes were down-regulated in PD0325901 treated cells compared to their media-only treated counterparts. This pattern was not seen with the BRAFWT cells. BRAFV600E cells exhibited this pattern following both a single treatment and two successive treatments with PD0325901.

Discussion: This pattern of gene expression is consistent with the hypothesis that resistance to small molecule MEK inhibition occurs via upregulation of an alternative pathway or activation of a redundant signalling pathway rather than through reactivation off the BRAF/MEK/ERK pathway. It also reinforces the theory that MEK inhibition induces differential effects in target cells dependent upon BRAF status.

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 B135.
Abstract B148: The miRNA-200 family regulates cell migration and metastasis in lung adenocarcinoma.
Authors: Blat Irene C. , Winslow Monte M. , Jacks Tyler E.
Published: June 2012

miRNAs are post-transcriptional regulators of genes involved in such canonical signaling pathways as the TGF-β and EGF pathways, both of which are frequently altered in tumor cells. miRNA downregulation results in upregulation of its target genes and ultimately aberrant signaling of pathways involved in invasion and migration, for example. To better understand how alterations in miRNA expression could lead to metastasis, we used a lung adenocarcinoma mouse model in which a lentivirus expressing the Cre recombinase activates oncogenic K-Ras and deletes p53, giving rise to primary lung tumors (T) and metastases (M). We performed miRNA expression profiling on 30 T and M derived cell lines and identified three members of the miR-200 family - miR-200b, miR-200c, miR-429 - to be significantly downregulated in the M lines compared to their related T line. To explore the functional contribution of the miR-200s to metastasis, we designed a miRNA sponge to stably inhibit endogenous miR-200 levels in T cell lines. We found miR-200 depletion promoted wound healing and cell migration towards either serum or EGF. Transplantation of the sponge-expressing lines via tail vein led to in vivo formation of more invasive, metastatic tumors compared to controls. Previously, the miR-200 family has been shown to inhibit the TGF-β target gene and EMT mediator, Zeb1. We have identified another miR-200 target, Epidermal Growth Factor Receptor Substrate 8 (Eps8), which mediates actin based cell motility. In miR-200 low (M) cells, Eps8 is expressed three-fold higher than in corresponding miR-200 high (T) cells. Additionally, exogenous expression of Eps8 in T lines promotes wound healing and cell migration, relative to control cells. Thus, our findings implicate the miR-200s as a class of metastasis regulators that modulate expression of genes functionally relevant in tumor cell dissemination and provide new targets for therapeutic intervention of late stage lung adenocarcinoma.

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 B148.
Abstract B151: Src inhibitor dasatinib reduces the metastatic phenotype of breast cancer cells.
Authors: Saffran Veronica , Siemann Dietmar
Published: June 2012

Subsequent to escaping the primary tumor, a successful metastatic tumor cell has to survive in the bloodstream, invade normal tissue at a secondary site, proliferate, and induce angiogenesis. Src is a non-receptor tyrosine kinase that is frequently over-expressed in malignances, and increased Src activity may be associated with poor patient prognosis. Src is well known to contribute to the metastatic phenotype of tumor cells through conferral of increased motility, migration, and invasion. Since these cellular functions are key components of the metastatic cascade, Src may be a novel target for breast cancer therapy. The present studies were undertaken to investigate whether molecular intervention in Src associated signaling could impact the metastatic phenotype of tumor cells. Specifically, we evaluated the in vitro and in vivo efficacy of the potent, selective and orally available Src inhibitor Dasatinib (BMS 354825) in the highly metastatic 4T1 murine mammary adenocarcinoma cell line.

Dasatinib was evaluated in vitro for the ability to inhibit migration and invasion in the 4T1 cell line. The results showed that Dasatinib treatment (50–100 nM) significantly inhibited both migration and invasion in a dose dependent manner (6- to 10-fold for the doses studied). To examine the effect of Dasatinib on tumor cell-induced angiogenesis in vivo, an intradermal angiogenesis assay was used. Briefly, 4T1 tumor cells were inoculated intradermally on the ventral surface of athymic nude (Ncr nu/nu) mice and 3 days later the mice were euthanized and skin flaps were removed for visual quantification of the number of blood vessels intersecting each inoculate. Mice received daily doses of either Dasatinib (5 to 15 mg/kg) or vehicle by oral gavage. The results showed that Dasatinib treatment inhibited 4T1 tumor cell-induced angiogenesis by up to 60%.

In summary, Dasatinib was found to significantly inhibit multiple cell functions critical to the successful dissemination of 4T1 breast cancer cells. The results suggest that Dasatinib may be useful in the reduction of breast cancer metastasis, and studies examining its impact on 4T1 metastases formation are currently ongoing.

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 B151.
Abstract B154: A first-in-human trial of GDC-0068: A novel, oral, ATP-competitive Akt inhibitor, demonstrates robust suppression of the Akt pathway in surrogate and tumor tissues.
Authors: Yan Yibing , Wagle Marie-Claire , Punnoose Elizabeth , Musib Luna , Budha Nageshwar , Nannini Michelle , Lin Kui , Liederer Bianca M. , Murli Sumati , Ramakrishnan Vanitha , Patel Premal , Cervantes Andrs , Tabernero Josep
Published: June 2012

GDC-0068 is a highly selective ATP-competitive small molecule that inhibits all three isoforms of Akt with IC50 values of 5 to 30 nM. GDC-0068 selectively inhibits cancer cells with activated Akt signaling (e.g. via PTEN loss or PIK3CA mutations). Patients with advanced solid tumors were treated with GDC-0068 using a 3+3 escalation design. GDC-0068 was dosed PO QD on a 21-day on, 7-day off schedule; endpoints included safety, pharmacokinetics (PK) and determination of pathway knockdown. Pharmacodynamics (PD) endpoints in surrogate tissue [platelet rich plasma (PRP)] were evaluated in all patients. In addition, at least two patients per cohort had pre- and on-treatment (day 15) tumor biopsies at doses ≥100mg QD. The tumor tissue samples were evaluated using reverse phase protein array (RPPA).

Thirty patients were enrolled across 7 cohorts (25, 50, 100, 200, 400, 600 and 800 mg QD). GDC-0068 was generally well-tolerated at doses ≤ 600 mg. Preliminary PK analyses show a dose proportional increase in exposure over the dose range tested. In addition, clinical exposures at doses ≥ 200 mg QD met or exceeded GDC-0068 exposures associated with tumor stasis in multiple PTEN null preclinical xenograft models. PK/PD evaluation showed dose-dependent Akt pathway inhibition in the PRP assay, with ≥70% inhibition of pGSK3 in all patients at doses ≥ 200 mg QD. Pre- and on-treatment tumor biopsies showed ≥50% decrease in pPRAS40 and cyclin D1 in multiple patients at doses of 200 mg QD and higher. In addition, evidence of feedback activation of the MAP kinase pathway after treatment with GDC-0068 was observed in biopsy samples. One patient with PTEN low/ PIK3CA H1047R/ KRAS wt CRC had prolonged stable disease and showed Akt pathway suppression by multiple downstream markers.

GDC-0068 is well tolerated at doses ≤ 600 mg with a favorable safety profile and dose proportional pharmacokinetics. Treatment with GDC-0068 results in substantial pathway knockdown in both surrogate and tumor tissues at doses ≥ 200 mg QD.

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 B154.
Abstract B155: A phase I study of the MEK inhibitor GSK1120212 (GSK212) in combination with PI3K/mTOR inhibitor GSK2126458 (GSK458) in patients with advanced solid tumors.
Authors: Grilley-Olson Juneko E. , Bedard Phillip , Fasolo Angelica , Blackman Samuel C. , Cartee Leanne , Baker-Neblett Katherine L. , Sun Peng , Infante Jeffrey R.
Published: June 2012

Background: This is a Phase I, open-label, dose escalation, pharmacokinetic (PK), pharmacodynamic (PD) and safety study in patients (pts) with advanced solid tumors exploring the combination of the investigational drugs GSK458 and GSK212. GSK212 is a reversible, highly selective, allosteric inhibitor of mitogen-activated extracellular signal regulated kinases 1 and 2 (MEK1 and MEK2). GSK458 is a potent, reversible, ATP-competitive, pan-phosphoinositide-3 kinase (PI3K) inhibitor, which also inhibits the mammalian target of rapamycin (mTOR), and the common activating mutations of catalytic isoform p110α. The MTD for daily, continuous dosing of monotherapy GSK458 is 2.5mg and GSK212 is 2.0mg.

Methods: The study consists of two parts: dose escalation in Part 1 (ongoing) uses a zone design (3+3 rules) to study safety, tolerability, PK, PD and clinical activity, and to establish the maximum tolerated doses (MTDs) and schedules for the combination. Adult pts with relapsed or refractory solid tumors are receiving oral doses of GSK458+GSK 212 once daily until disease progression or toxicity. Efficacy is assessed using RECIST 1.1. Part 2 will examine safe dose combinations from Part 1 in patients with tumors likely to respond to MEK/PI3K pathway inhibition. Genetic and protein profiles collected from blood and tumor samples will be used to explore relationships between predictive biomarkers of response and efficacy.

Results: 34 pts(45% female) with a mean age of 58y (range 37–82y) have enrolled. Safety data includes31 subjects who have received ≥1 dose of GSK458+GSK212. Most commonly reported drug-related AEs >10%, n=31) include rash (68%; G3/4, 3%), diarrhea (42%; G3/4, 6%), nausea (29%; G3/4, 0%), vomiting (23%; G3/4, 3%), decreased appetite (19%; G3/4, 0%), stomatitis (13%; G3/4, 3%) and fatigue (13%; G3/4; 3%). Of 21 serious adverse events (SAEs) reported in 14 pts, 3 were considered related to study drug. Stable disease has been observed in several patients with the longest being at 6 months (renal cell carcinoma and colorectal cancer).

The combination of GSK458 0.5 mg + GSK212 2.0 mg exceeded the MTD. However, once daily and continuous combination dosing of GSK458 (0.5, 1.0 or 1.5mg) + GSK212 ≤ 2.0 mg were well tolerated.

Conclusions: The preliminary safety profile and anti-tumor activity of this combination warrants further investigation in continued dose escalation and planned expansion cohorts.

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 B155.
Abstract B160: PWT33597 promotes apoptosis in tumor cells through balanced dual inhibition of PI3K alpha and mTOR.
Authors: Matthews David J. , Ventura Richard , Tai Albert , Holst Charles , O'Farrell Marie
Published: June 2012

Phosphatidylinositol 3-kinase (PI3K) and mammalian target of rapamycin (mTOR) serve as critical nodes in an intracellular signaling network that regulates cell growth, proliferation and survival, and dysregulation of this signaling network is frequently found in tumor cells. PWT33597 is a novel, balanced, dual inhibitor of PI3K alpha and mTOR currently in clinical development. To dissect the relative contribution of PI3K and mTOR pathways to activity, we explored the effects of various mono versus dual PI3K and mTOR inhibitors on intracellular signaling pathways, proliferation and apoptosis in cancer cell lines harboring PI3K alpha mutations. The panel of inhibitors used includes compounds that are highly selective for PI3K (GDC-0941), molecules that are highly selective for mTORC1/2 (AZD8055), as well as dual inhibitors such as PWT33597, BEZ235, PF-04691502 and GSK2126453.

Our results indicate that compounds predominantly inhibiting PI3K have modest effects on phosphorylation of pathway proteins downstream of mTOR (in particular 4EBP), and do not lead to sustained induction of apoptosis markers such as PARP. Conversely, compounds that predominantly target mTORC1/2 produce feedback activation of PI3K signaling, resulting in increased phosphorylation of AKT (T308) and very limited effects on cell death. Dual PI3K/mTOR inhibitors produce more significant inhibition across the pathway, in particular leading to sustained inhibition of pAKT (S473 and T308) and p4EBP (T37/46), decreased release of normal feedback loops within the pathway, and an increased percentage of apoptotic cells as measured by percent population in sub-G1 phase of the cell cycle. In particular, PWT33597 produces potent and sustained pathway inhibition both for PI3K and mTOR-dependent readouts (pAKT S473, pAKT T308 and p4EBP T37/46), and maintains induction of apoptotic markers, resulting in cell death.

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 B160.
Abstract B169: Antitumor activity of a new compound NBRI17671 produced by Acremonium sp. CR17671.
Authors: Kawada Manabu , Usami Ihomi , Someno Tetsuya , Watanabe Takumi , Abe Hikaru , Inoue Hiroyuki , Ohba Shun-ichi , Masuda Tohru , Nomoto Akio
Published: June 2012

Tumor microenvironment is now getting much attention as tumor therapeutic targets. We have been studying the tumor-stromal cell interactions and found new candidates for antitumor drugs. We have then reported various compounds that inhibit tumor growth through the modulation of the tumor-stromal cell interactions (Cancer Res 66, 4419, 2006; Int J Cancer 126, 810, 2010; J Antibiot 63, 319, 2010). In this report we have focused on the binding of cells to ligands.

Interaction between the receptor for advanced glycation end-product (RAGE) and amphoterin plays an important role in tumor growth and metastasis. Because the abrogation of the interaction results in the inhibition of the tumor growth and metastasis, we designed a screening system for an inhibitor of the interaction between RAGE and amphoterin. In the course of our screening of the inhibitor, we isolated a novel natural compound NBRI17671 (1) from the fermentation broth of Acremonium sp. CR17671. We also modified 1 into more active NBRI17671al (2). While 1 at 50 μg/ml weakly inhibited binding of various cells to amphoterin, 2 at 50 μg/ml inhibited it more than 50% of control. Compound 2 effectively inhibited the tumor growth of glioma and lung tumor xenografts in mice at 25 mg/kg. Furthermore, 2 was found to downregulate MAPK activity in the tumor cells. Collaborator: Meiji Seika Pharma.

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 B169.