Publications by authors named "Keith B Glaser"

45 Publications

Identification of VEGF Signaling Inhibition-Induced Glomerular Injury in Rats through Site-Specific Urinary Biomarkers.

Int J Mol Sci 2021 Nov 23;22(23). Epub 2021 Nov 23.

Global Pharmaceutical Research and Development, AbbVie, 1 North Waukegan Road, North Chicago, IL 60064, USA.

Cancer therapies targeting the vascular endothelial growth factor (VEGF) signaling pathway can lead to renal damage by disrupting the glomerular ultrafiltration apparatus. The objective of the current study was to identify sensitive biomarkers for VEGF inhibition-induced glomerular changes in rats. Male Sprague-Dawley rats were administered an experimental VEGF receptor (VEGFR) inhibitor, ABT-123, for seven days to investigate the correlation of several biomarkers with microscopic and ultrastructural changes. Glomeruli obtained by laser capture microdissection were also subjected to gene expression analysis to investigate the underlying molecular events of VEGFR inhibition in glomerulus. ABT-123 induced characteristic glomerular ultrastructural changes in rats, including fusion of podocyte foot processes, the presence of subendothelial electron-dense deposits, and swelling and loss of fenestrations in glomerular endothelium. The subtle morphological changes cannot be detected with light microscopy or by changes in standard clinical chemistry and urinalysis. However, urinary albumin increased 44-fold as early as Day three. Urinary β2-microglobulin levels were also increased. Other urinary biomarkers that are typically associated with tubular injury were not significantly impacted. Such patterns in urinary biomarkers can provide valuable diagnostic insight to VEGF inhibition therapy-induced glomeruli injuries.
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http://dx.doi.org/10.3390/ijms222312629DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8657489PMC
November 2021

Identification of novel resistance mechanisms to NAMPT inhibition via the de novo NAD biosynthesis pathway and NAMPT mutation.

Biochem Biophys Res Commun 2017 09 26;491(3):681-686. Epub 2017 Jul 26.

AbbVie Inc., 1 North Waukegan Rd., North Chicago, IL 60064, United States. Electronic address:

Cancer cells have an unusually high requirement for the central and intermediary metabolite nicotinamide adenine dinucleotide (NAD), and NAD depletion ultimately results in cell death. The rate limiting step within the NAD salvage pathway required for converting nicotinamide to NAD is catalyzed by nicotinamide phosphoribosyltransferase (NAMPT). Targeting NAMPT has been investigated as an anti-cancer strategy, and several highly selective small molecule inhibitors have been found to potently inhibit NAMPT in cancer cells, resulting in NAD depletion and cytotoxicity. To identify mechanisms that could cause resistance to NAMPT inhibitor treatment, we generated a human fibrosarcoma cell line refractory to the highly potent and selective NAMPT small molecule inhibitor, GMX1778. We uncovered novel and unexpected mechanisms of resistance including significantly increased expression of quinolinate phosphoribosyl transferase (QPRT), a key enzyme in the de novo NAD synthesis pathway. Additionally, exome sequencing of the NAMPT gene in the resistant cells identified a single heterozygous point mutation that was not present in the parental cell line. The combination of upregulation of the NAD de novo synthesis pathway through QPRT over-expression and NAMPT mutation confers resistance to GMX1778, but the cells are only partially resistant to next-generation NAMPT inhibitors. The resistance mechanisms uncovered herein provide a potential avenue to continue exploration of next generation NAMPT inhibitors to treat neoplasms in the clinic.
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http://dx.doi.org/10.1016/j.bbrc.2017.07.143DOI Listing
September 2017

JAK2V617F drives Mcl-1 expression and sensitizes hematologic cell lines to dual inhibition of JAK2 and Bcl-xL.

PLoS One 2015 17;10(3):e0114363. Epub 2015 Mar 17.

Oncology Division, Research & Development, AbbVie Inc., North Chicago, Illinois, United States of America.

Constitutive activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) axis is fundamental to the molecular pathogenesis of a host of hematological disorders, including acute leukemias and myeloproliferative neoplasms (MPN). We demonstrate here that the major JAK2 mutation observed in these diseases (JAK2V617F) enforces Mcl-1 transcription via STAT3 signaling. Targeting this lesion with JAK inhibitor I (JAKi-I) attenuates STAT3 binding to the Mcl-1 promoter and suppresses Mcl-1 transcript and protein expression. The neutralization of Mcl-1 in JAK2V617F-harboring myelodyssplastic syndrome cell lines sensitizes them to apoptosis induced by the BH3-mimetic and Bcl-xL/Bcl-2 inhibitor, ABT-263. Moreover, simultaneously targeting JAK and Bcl-xL/-2 is synergistic in the presence of the JAK2V617F mutation. These findings suggest that JAK/Bcl-xL/-2 inhibitor combination therapy may have applicability in a range of hematological disorders characterized by activating JAK2 mutations.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0114363PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4362760PMC
February 2016

Preclinical characterization of ABT-348, a kinase inhibitor targeting the aurora, vascular endothelial growth factor receptor/platelet-derived growth factor receptor, and Src kinase families.

J Pharmacol Exp Ther 2012 Dec 30;343(3):617-27. Epub 2012 Aug 30.

Abbott Oncology, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL, USA.

ABT-348 [1-(4-(4-amino-7-(1-(2-hydroxyethyl)-1H-pyrazol-4-yl)thieno[3,2-c]pyridin-3-yl)phenyl)-3-(3-fluorophenyl)urea] is a novel ATP-competitive multitargeted kinase inhibitor with nanomolar potency (IC(50)) for inhibiting binding and cellular autophosphorylation of Aurora B (7 and 13 nM), C (1 and 13 nM), and A (120 and 189 nM). Cellular activity against Aurora B is reflected by inhibition of phosphorylation of histone H3, induction of polyploidy, and inhibition of proliferation of a variety of leukemia, lymphoma, and solid tumor cell lines (IC(50) = 0.3-21 nM). In vivo inhibition of Aurora B was confirmed in an engrafted leukemia model by observing a decrease in phosphorylation of histone H3 that persisted in a dose-dependent manner for 8 h and correlated with plasma concentration of ABT-348. Evaluation of ABT-348 across a panel of 128 kinases revealed additional potent binding activity (K(i) < 30 nM) against vascular endothelial growth factor receptor (VEGFR)/platelet-derived growth factor receptor (PDGFR) families and the Src family of cytoplasmic tyrosine kinases. VEGFR/PDGFR binding activity correlated with inhibition of autophosphorylation in cells and inhibition of vascular endothelial growth factor (VEGF)-stimulated endothelial cell proliferation (IC(50) ≤ 0.3 nM). Evidence of on-target activity in vivo was provided by the potency for blocking VEGF-mediated vascular permeability and inducing plasma placental growth factor. Activity against the Src kinase family was evident in antiproliferative activity against BCR-ABL chronic myeloid leukemia cells and cells expressing the gleevec-resistant BCR-ABL T315I mutation. On the basis of its unique spectrum of activity, ABT-348 was evaluated and found effective in representative solid tumor [HT1080 and pancreatic carcinoma (MiaPaCa), tumor stasis] and hematological malignancy (RS4;11, regression) xenografts. These results provide the rationale for clinical assessment of ABT-348 as a therapeutic agent in the treatment of cancer.
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http://dx.doi.org/10.1124/jpet.112.197087DOI Listing
December 2012

Exploration of diverse hinge-binding scaffolds for selective Aurora kinase inhibitors.

Bioorg Med Chem Lett 2012 Jul 7;22(14):4528-31. Epub 2012 Jun 7.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6100, USA.

Four hinge-binding scaffolds have been explored for novel selective Aurora kinase inhibitors. The structure activity relationship, selectivity and pharmacokinetic profiles have been evaluated.
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http://dx.doi.org/10.1016/j.bmcl.2012.05.125DOI Listing
July 2012

Pyrazole diaminopyrimidines as dual inhibitors of KDR and Aurora B kinases.

Bioorg Med Chem Lett 2012 Jul 26;22(14):4750-5. Epub 2012 May 26.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6100, USA.

In an effort to identify kinase inhibitors with dual KDR/Aurora B activity and improved aqueous solubility compared to the Abbott dual inhibitor ABT-348, a series of novel pyrazole pyrimidines structurally related to kinase inhibitor AS703569 were prepared. SAR work provided analogs with significant cellular activity, measureable aqueous solubility and moderate antitumor activity in a mouse tumor model after weekly ip dosing. Unfortunately these compounds were pan-kinase inhibitors that suffered from narrow therapeutic indices which prohibited their use as antitumor agents.
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http://dx.doi.org/10.1016/j.bmcl.2012.05.067DOI Listing
July 2012

Thienopyridine ureas as dual inhibitors of the VEGF and Aurora kinase families.

Bioorg Med Chem Lett 2012 May 14;22(9):3208-12. Epub 2012 Mar 14.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6100, USA.

In an effort to identify multi-targeted kinase inhibitors with a novel spectrum of kinase activity, a screen of Abbott proprietary KDR inhibitors against a broad panel of kinases was conducted and revealed a series of thienopyridine ureas with promising activity against the Aurora kinases. Modification of the diphenyl urea and C7 moiety of these compounds provided potent inhibitors with good pharmacokinetic profiles that were efficacious in mouse tumor models after oral dosing. Compound 2 (ABT-348) of this series is currently undergoing Phase I clinical trials in solid and hematological cancer populations.
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http://dx.doi.org/10.1016/j.bmcl.2012.03.035DOI Listing
May 2012

1-Benzyl-3-cetyl-2-methylimidazolium iodide (NH125) induces phosphorylation of eukaryotic elongation factor-2 (eEF2): a cautionary note on the anticancer mechanism of an eEF2 kinase inhibitor.

J Biol Chem 2011 Dec 21;286(51):43951-43958. Epub 2011 Oct 21.

Cancer Research and Advanced Technology, Abbott Laboratories, Abbott Park, Illinois 60064.

Eukaryotic elongation factor-2 kinase (eEF2K) relays growth and stress signals to protein synthesis through phosphorylation and inactivation of eukaryotic elongation factor 2 (eEF2). 1-Benzyl-3-cetyl-2-methylimidazolium iodide (NH125) is a widely accepted inhibitor of mammalian eEF2K and an efficacious anti-proliferation agent against different cancer cells. It implied that eEF2K could be an efficacious anticancer target. However, eEF2K siRNA was ineffective against cancer cells including those sensitive to NH125. To test if pharmacological intervention differs from siRNA interference, we identified a highly selective small molecule eEF2K inhibitor A-484954. Like siRNA, A-484954 had little effect on cancer cell growth. We carefully examined the effect of NH125 and A-484954 on phosphorylation of eEF2, the known cellular substrate of eEF2K. Surprisingly, NH125 increased eEF2 phosphorylation, whereas A-484954 inhibited the phosphorylation as expected for an eEF2K inhibitor. Both A-484954 and eEF2K siRNA inhibited eEF2K and reduced eEF2 phosphorylation with little effect on cancer cell growth. These data demonstrated clearly that the anticancer activity of NH125 was more correlated with induction of eEF2 phosphorylation than inhibition of eEF2K. Actually, induction of eEF2 phosphorylation was reported to correlate with inhibition of cancer cell growth. We compared several known inducers of eEF2 phosphorylation including AMPK activators and an mTOR inhibitor. Interestingly, stronger induction of eEF2 phosphorylation correlated with more effective growth inhibition. We also explored signal transduction pathways leading to NH125-induced eEF2 phosphorylation. Preliminary data suggested that NH125-induced eEF2 phosphorylation was likely mediated through multiple pathways. These observations identified an opportunity for a new multipathway approach to anticancer therapies.
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http://dx.doi.org/10.1074/jbc.M111.301291DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3243513PMC
December 2011

Discovery of potent and selective thienopyrimidine inhibitors of Aurora kinases.

Bioorg Med Chem Lett 2011 Sep 29;21(18):5620-4. Epub 2011 Jun 29.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6100, USA.

In an effort to discover Aurora kinase inhibitors, an HTS hit revealed an amide containing pyrrolopyrimidine compound. Replacement of the pyrrolopyrimidine residue with a thienopyrimidine moiety led to a series of potent and selective Aurora inhibitors.
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http://dx.doi.org/10.1016/j.bmcl.2011.06.041DOI Listing
September 2011

The multitargeted receptor tyrosine kinase inhibitor linifanib (ABT-869) induces apoptosis through an Akt and glycogen synthase kinase 3β-dependent pathway.

Mol Cancer Ther 2011 Jun 6;10(6):949-59. Epub 2011 Apr 6.

Division of Hematology-Oncology, Gwynne Hazen Cherry Memorial Laboratories, Mattel Children's Hospital UCLA, Jonsson Comprehensive Cancer Center, University of California-Los Angeles, Los Angeles, CA 90095, USA.

The FMS-like receptor tyrosine kinase 3 (FLT3) plays an important role in controlling differentiation and proliferation of hematopoietic cells. Activating mutations in FLT3 occur in patients with acute myeloid leukemia (AML; 15%-35%), resulting in abnormal cell proliferation. Furthermore, both adult and pediatric patients with AML harboring the FLT3 internal tandem duplication (ITD) mutation have a poor prognosis. Several inhibitors have been developed to target mutant FLT3 for the treatment of AML, yet the molecular pathways affected by drug inhibition of the mutated FLT3 receptor alone have not been characterized as yet. Linifanib (ABT-869) is a multitargeted tyrosine kinase receptor inhibitor that suppresses FLT3 signaling. In this article, we show that treatment with linifanib inhibits proliferation and induces apoptosis in ITD mutant cells in vitro and in vivo. We show that treatment with linifanib reduces phosphorylation of Akt and glycogen synthase kinase 3β (GSK3β). In addition, we show that inhibition of GSK3β decreases linifanib-induced apoptosis. This study shows the importance of GSK3 as a potential target for AML therapy, particularly in patients with FLT3 ITD mutations.
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http://dx.doi.org/10.1158/1535-7163.MCT-10-0904DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3112478PMC
June 2011

Cyanobacterial Microcystis aeruginosa lipopolysaccharide elicits release of superoxide anion, thromboxane B₂, cytokines, chemokines, and matrix metalloproteinase-9 by rat microglia.

Toxicol Sci 2011 May 28;121(1):63-72. Epub 2011 Feb 28.

Department of Pharmacology, Chicago College of Osteopathic Medicine, Midwestern University, Downers Grove, Illinois 60515, USA.

Microcystis aeruginosa (M. aeruginosa) is a cosmopolitan Gram-negative cyanobacterium that may contaminate freshwater by releasing toxins, such as lipopolysaccharide (LPS) during aquatic blooms, affecting environmental and human health. The putative toxic effects of cyanobacterial LPS on brain microglia, a glial cell type that constitutes the main leukocyte-dependent source of reactive oxygen species in the central nervous system, are presently unknown. We tested the hypothesis that in vitro concentration- and time-dependent exposure to M. aeruginosa LPS strain UTCC 299 would activate rat microglia and the concomitant generation of superoxide anion (O₂⁻). After a 17-h exposure of microglia to M.aeruginosa LPS, the following concentration-dependent responses were observed: 0.1-100 ng/ml M. aeruginosa LPS enhanced O₂⁻ generation, with limited inflammatory mediator generation; 1000-10,000 ng/ml M. aeruginosa LPS caused thromboxane B₂ (TXB₂), matrix metalloproteinase-9 (MMP-9), and macrophage inflammatory protein-2 (MIP-2/CXCL2) release, concurrent with maximal O₂⁻ generation; 100,000 ng/mL M. aeruginosa LPS deactivated O₂⁻ production but maintained elevated levels of TXB₂, MMP-9, tumor necrosis factor-α (TNF-α), interleukin 1-α (IL-1α), and interleukin-6 (IL-6), macrophage inflammatory protein 1α (MIP-1α/CCL3), and MIP-2/CXCL2, with concomitant lactic dehydrogenase release. Although M. aeruginosa LPS was consistently less potent than Escherichia coli LPS, with the exception of O₂⁻, TXB₂, and MCP-1/CCL2 generation, it was more efficacious because higher levels of MMP-9, TNF-α, IL-1α, IL-6, MIP-1α/CCL3, and MIP-2/CXCL2 were produced. Our in vitro studies suggest that one or more of the inflammatory mediators released during M. aeruginosa LPS stimulation of microglia may play a critical role in the subsequent ability of microglia to generate O₂⁻. To our knowledge, this is the first experimental evidence that LPS isolated from a M. aeruginosa strain, can activate brain microglia in vitro, as well as the release of O₂⁻, and other inflammatory mediators hypothesized to be involved in neuroinflammation and neurodegeneration.
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http://dx.doi.org/10.1093/toxsci/kfr045DOI Listing
May 2011

Bcl-XL represents a druggable molecular vulnerability during aurora B inhibitor-mediated polyploidization.

Proc Natl Acad Sci U S A 2010 Jul 28;107(28):12634-9. Epub 2010 Jun 28.

Oncology Division and Advanced Technologies, Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064-6121, USA.

Aurora kinase B inhibitors induce apoptosis secondary to polyploidization and have entered clinical trials as an emerging class of neocytotoxic chemotherapeutics. We demonstrate here that polyploidization neutralizes Mcl-1 function, rendering cancer cells exquisitely dependent on Bcl-XL/-2. This "addiction" can be exploited therapeutically by combining aurora kinase inhibitors and the orally bioavailable BH3 mimetic, ABT-263, which inhibits Bcl-XL, Bcl-2, and Bcl-w. The combination of ABT-263 with aurora B inhibitors produces a synergistic loss of viability in a range of cell lines of divergent tumor origin and exhibits more sustained tumor growth inhibition in vivo compared with aurora B inhibitor monotherapy. These data demonstrate that Bcl-XL/-2 is necessary to support viability during polyploidization in a variety of tumor models and represents a druggable molecular vulnerability with potential therapeutic utility.
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http://dx.doi.org/10.1073/pnas.0913615107DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2906553PMC
July 2010

The odyssey of marine pharmaceuticals: a current pipeline perspective.

Trends Pharmacol Sci 2010 Jun 2;31(6):255-65. Epub 2010 Apr 2.

Department of Pharmacology, Chicago College of Osteopathic Medicine, Midwestern University, 555 31st Street, Downers Grove, IL 60515, USA.

The global marine pharmaceutical pipeline consists of three Food and Drug Administration (FDA) approved drugs, one EU registered drug, 13 natural products (or derivatives thereof) in different phases of the clinical pipeline and a large number of marine chemicals in the preclinical pipeline. In the United States there are three FDA approved marine-derived drugs, namely cytarabine (Cytosar-U((R)), Depocyt((R))), vidarabine (Vira-A((R))) and ziconotide (Prialt((R))). The current clinical pipeline includes 13 marine-derived compounds that are either in Phase I, Phase II or Phase III clinical trials. Several key Phase III studies are ongoing and there are seven marine-derived compounds now in Phase II trials. The preclinical pipeline continues to supply several hundred novel marine compounds every year and those continue to feed the clinical pipeline with potentially valuable compounds. From a global perspective the marine pharmaceutical pipeline remains very active, and now has sufficient momentum to deliver several additional compounds to the marketplace in the near future; this review provides a current view of the pipeline.
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http://dx.doi.org/10.1016/j.tips.2010.02.005DOI Listing
June 2010

ABT-869 inhibits the proliferation of Ewing Sarcoma cells and suppresses platelet-derived growth factor receptor beta and c-KIT signaling pathways.

Mol Cancer Ther 2010 Mar 2;9(3):653-60. Epub 2010 Mar 2.

Division of Hematology/Oncology, Department of Pediatrics, Gwynne Hazen Cherry Memorial Laboratories, Jonsson Comprehensive Cancer Center, David Geffen School of Medicine at the University of California at Los Angeles, Los Angeles, California 90095-1752, USA.

The Ewing Sarcoma (EWS) family of tumors is one of the most common tumors diagnosed in children and adolescents and is characterized by a translocation involving the EWS gene. Despite advances in chemotherapy, the prognosis of metastatic EWS is poor with an overall survival of <30% after 5 years. EWS tumor cells express the receptor tyrosine kinases, platelet-derived growth factor receptor (PDGFR) and c-KIT. ABT-869 is a multitargeted small-molecule inhibitor that targets Fms-like tyrosine kinase-3, c-KIT, vascular endothelial growth receptors, and PDGFRs. To determine the potential therapeutic benefit of ABT-869 in EWS cells, we examined the effects of ABT-869 on EWS cell lines and xenograft mouse models. ABT-869 inhibited the proliferation of two EWS cell lines, A4573 and TC71, at an IC(50) of 1.25 and 2 mumol/L after 72 h of treatment, respectively. The phosphorylation of PDGFRbeta, c-KIT, and extracellular signal-regulated kinases was also inhibited. To examine the effects of ABT-869 in vivo, the drug was given to mice injected with EWS cells. We observed inhibition of growth of EWS tumor cells in a xenograft mouse model and prolonged survival in a metastatic mouse model of EWS. Therefore, our in vitro and in vivo studies show that ABT-869 inhibits proliferation of EWS cells through inhibition of PDGFRbeta and c-KIT pathways.
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http://dx.doi.org/10.1158/1535-7163.MCT-09-0812DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2837519PMC
March 2010

A renaissance in marine pharmacology: from preclinical curiosity to clinical reality.

Biochem Pharmacol 2009 Sep 22;78(5):440-8. Epub 2009 Apr 22.

Cancer Research R47J-AP9, Abbott Laboratories, Abbott Park, IL 60064-6121, USA.

Marine pharmacology, the pharmacology of marine natural products, has been for some time more associated with marine natural products chemistry rather than mainstay pharmacology. However, in recent years a renaissance has occurred in this area of research, and has seen the US Food & Drug Administration (FDA) approval in 2004 of Prialt (ziconotide, omega-conotoxin MVIIA) the synthetic equivalent of a conopeptide found in marine snails, used for the management of severe chronic pain. Furthermore Yondelis) (trabectedin, ET-743) an antitumor agent scovered in a marine colonial tunicate, and now produced synthetically, receiving Orphan Drug designation from the European Commission (EC) and FDA for soft tissue sarcomas and ovarian cancer and its registration in 2007 in the EU for the treatment of soft tissue sarcoma. The approval/marketing of so few marine natural products has come after many years of research primarily by the academic community and the sporadic involvement of major pharmaceutical companies. This commentary, through the opinions provided by several leaders in the marine natural products field, will examine the potential reasons and perceptions from both the academic and pharmaceutical communities regarding the development of marine natural products as viable therapeutic entities.
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http://dx.doi.org/10.1016/j.bcp.2009.04.015DOI Listing
September 2009

Enhanced activation of STAT pathways and overexpression of survivin confer resistance to FLT3 inhibitors and could be therapeutic targets in AML.

Blood 2009 Apr 14;113(17):4052-62. Epub 2009 Jan 14.

Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.

To further investigate potential mechanisms of resistance to FLT3 inhibitors, we developed a resistant cell line by long-term culture of MV4-11 cells with ABT-869, designated as MV4-11-R. Gene profiling reveals up-regulation of FLT3LG (FLT3 ligand) and BIRC5 (survivin), but down-regulation of SOCS1, SOCS2, and SOCS3 in MV4-11-R cells. Hypermethylation of these SOCS genes leads to their transcriptional silencing. Survivin is directly regulated by STAT3. Stimulation of the parental MV4-11 cells with FLT3 ligand increases the expression of survivin and phosphorylated protein STAT1, STAT3, STAT5. Targeting survivin by short-hairpin RNA (shRNA) in MV4-11-R cells induces apoptosis and augments ABT-869-mediated cytotoxicity. Overexpression of survivin protects MV4-11 from apoptosis. Subtoxic dose of indirubin derivative (IDR) E804 resensitizes MV4-11-R to ABT-869 treatment by inhibiting STAT signaling activity and abolishing survivin expression. Combining IDR E804 with ABT-869 shows potent in vivo efficacy in the MV4-11-R xenograft model. Taken together, these results demonstrate that enhanced activation of STAT pathways and overexpression of survivin are important mechanisms of resistance to ABT-869, suggesting that the STAT pathways and survivin could be potential targets for reducing resistance developed in patients receiving FLT3 inhibitors.
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http://dx.doi.org/10.1182/blood-2008-05-156422DOI Listing
April 2009

ABT-869, a multi-targeted tyrosine kinase inhibitor, in combination with rapamycin is effective for subcutaneous hepatocellular carcinoma xenograft.

J Hepatol 2008 Dec 1;49(6):985-97. Epub 2008 Oct 1.

Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 5 Lower Kent Ridge Road, Singapore 119074, Singapore.

Background/aims: Receptor tyrosine kinase inhibitors (RTKIs) and mTOR inhibitors are potential novel anticancer therapies for HCC. We hypothesized that combination targeted on distinctive signal pathways would provide synergistic therapeutics.

Methods: ABT-869, a novel RTKI, and rapamycin were investigated in HCC pre-clinical models.

Results: Rapamycin, but not ABT-869, inhibited in vitro growth of Huh7 and SK-HEP-1 HCC cells in a dose dependant manner. However, in subcutaneous Huh7 and SK-HEP-1 xenograft models, either ABT-869 or rapamycin can significantly reduce tumor burden. Combination treatment reduced the tumors to the lowest volume (95+/-20mm(3)), and was significantly better than single agent treatment (p<0.05). Immunohistochemical staining of tumor shows that ABT-869 potently inhibits VEGF in HCC in vivo. In addition, the MAPK signaling pathway has been inhibited by significant inhibition of phosphorylation of p44/42 MAP kinase by ABT-869 in vivo. Rapamycin inhibits phosphorylation of p70 S6 kinase and 4E-BP-1, downstream targets of mTOR, and decreases VEGF. Combination treatment showed synergistic effect on expression levels of p27 in vivo. Dramatic inhibition of neo-angiogenesis by ABT-869 was also demonstrated.

Conclusions: HCC could potentially be treated with the combination treatment of ABT-869 and rapamycin. Clinical trials on combination therapy are warranted.
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http://dx.doi.org/10.1016/j.jhep.2008.08.010DOI Listing
December 2008

7-Aminopyrazolo[1,5-a]pyrimidines as potent multitargeted receptor tyrosine kinase inhibitors.

J Med Chem 2008 Jul 17;51(13):3777-87. Epub 2008 Jun 17.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois 60064-6100, USA.

7-Aminopyrazolo[1,5- a]pyrimidine urea receptor tyrosine kinase inhibitors have been discovered. Investigation of structure-activity relationships of the pyrazolo[1,5- a]pyrimidine nucleus led to a series of 6-(4- N, N'-diphenyl)ureas that potently inhibited a panel of vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor (PDGFR) kinases. Several of these compounds, such as 34a, are potent inhibitors of kinase insert domain-containing receptor tyrosine kinase (KDR) both enzymatically (<10 nM) and cellularly (<10 nM). In addition, compound 34a possesses a favorable pharmacokinetic profile and demonstrates efficacy in the estradiol-induced murine uterine edema (UE) model (ED 50 = 1.4 mg/kg).
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http://dx.doi.org/10.1021/jm701397kDOI Listing
July 2008

Scaffold oriented synthesis. Part 2: Design, synthesis and biological evaluation of pyrimido-diazepines as receptor tyrosine kinase inhibitors.

Bioorg Med Chem Lett 2008 Apr 10;18(8):2691-5. Epub 2008 Mar 10.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60044, USA.

We report the discovery of the pyrimido-diazepine scaffolds as novel adenine mimics. Structure-based design led to the discovery of analogs with potent inhibitory activity against receptor tyrosine kinases, such as KDR, Flt3 and c-Kit. Compound 14 exhibited low nanomolar KDR enzymatic and cellular potencies (IC(50)=9 and 52 nM, respectively).
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http://dx.doi.org/10.1016/j.bmcl.2008.03.021DOI Listing
April 2008

3-amino-benzo[d]isoxazoles as novel multitargeted inhibitors of receptor tyrosine kinases.

J Med Chem 2008 Mar 9;51(5):1231-41. Epub 2008 Feb 9.

Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, Illinois 60064-6100, USA.

A series of benzoisoxazoles and benzoisothiazoles have been synthesized and evaluated as inhibitors of receptor tyrosine kinases (RTKs). Structure-activity relationship studies led to the identification of 3-amino benzo[ d]isoxazoles, incorporating a N, N'-diphenyl urea moiety at the 4-position that potently inhibited both the vascular endothelial growth factor receptor (VEGFR) and platelet-derived growth factor receptor families of RTKs. Within this series, orally bioavailable compounds possessing promising pharmacokinetic profiles were identified, and a number of compounds demonstrated in vivo efficacy in models of VEGF-stimulated vascular permeability and tumor growth. In particular, compound 50 exhibited an ED 50 of 2.0 mg/kg in the VEGF-stimulated uterine edema model and 81% inhibition in the human fibrosarcoma (HT1080) tumor growth model when given orally at a dose of 10 mg/kg/day.
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http://dx.doi.org/10.1021/jm701096vDOI Listing
March 2008

In vivo activity of ABT-869, a multi-target kinase inhibitor, against acute myeloid leukemia with wild-type FLT3 receptor.

Leuk Res 2008 Jul 26;32(7):1091-100. Epub 2007 Dec 26.

Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.

Neoangiogenesis plays an important role in leukemogenesis. We investigated the in vivo anti-leukemic effect of ABT-869 against AML with wild-type FLT3 using RFP transfected HL60 cells with in vivo imaging technology on both the subcutaneous and systemic leukemia xenograft models. ABT-869 showed a five-fold inhibition of tumor growth in comparison with vehicle control. IHC analysis revealed that ABT-869 decreased p-VEGFR1, Ki-67 labeling index, VEGF and remarkably increased apoptotic cells in the xenograft models. ABT-869 also reduced the leukemia burden and prolonged survival. Our study supports the rationale for clinically testing an anti-angiogenesis agent in AML with wild-type FLT3.
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http://dx.doi.org/10.1016/j.leukres.2007.11.025DOI Listing
July 2008

Identification of aminopyrazolopyridine ureas as potent VEGFR/PDGFR multitargeted kinase inhibitors.

Bioorg Med Chem Lett 2008 Jan 17;18(1):386-90. Epub 2007 Oct 17.

Cancer Research, Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6100, USA.

Tumor angiogenesis is mediated by KDR and other VEGFR and PDGFR kinases. Their inhibition presents an attractive approach for developing anticancer therapeutics. Here, we report a series of aminopyrazolopyridine ureas as potent VEGFR/PDGFR multitargeted kinase inhibitors. A number of compounds have been identified to be orally bioavailable and efficacious in the mouse edema model.
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http://dx.doi.org/10.1016/j.bmcl.2007.10.018DOI Listing
January 2008

Differential response of p53 and p21 on HDAC inhibitor-mediated apoptosis in HCT116 colon cancer cells in vitro and in vivo.

Int J Oncol 2007 Dec;31(6):1391-402

Department of Medicine 1, University Hospital Erlangen, D-91054, Erlangen, Germany.

We investigated the effect of a novel histone deacetylase inhibitor, A-423378.0, on the colon carcinoma cell line HCT116 and genetically modified derivatives lacking either p21(cip1/waf1) or p53. HCT116 cell lines were incubated with A-423378.0 at different concentrations for 3-120 h. Cell viability, proliferation and apoptosis rates were determined and verified by western blot, detection of mitochondrial membrane potential breakdown DeltaPsi(m), activation of caspases-3, -8 and cytokeratin 18 cleavage. A subcutaneous xenograft model was established in NMRI mice with daily intraperitoneal injections of 10 mg/kg for 14 days. All three HCT116 cell lines responded to A-423378.0 treatment in a dose- and time-dependent manner via induction of apoptosis as measured by breakdown of DeltaPsi(m) and BrdU incorporation. We identified that A-423378.0 induced the expression of TRAIL and TRAIL receptor, especially TRAIL-R2/hDR5, which was up-regulated in HCT116 cells after treatment with A-423378.0. In vivo, a growth inhibitory effect was observed with HDAC-I treatment, which was paralleled by a down-regulation of PCNA and a concomitant induction of apoptosis. Treatment of wild-type or knock-out HCT116 cells with A-423378.0 exerts potent anti-proliferative and pro-apoptotic effects in vitro and in vivo. A-423378.0 was able to induce apoptosis in both p21(WAF1) and p53 deficient tumour cells, which appeared to be mediated by the intrinsic cell death pathway. Interestingly, the effects of A-423378.0 on the extrinsic cell death pathway through activation of TRAIL and its signalling pathway indicate that A-423378.0 may be a potent new therapeutic compound for the treatment of advanced colorectal cancer.
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December 2007

G1P3, an IFN-induced survival factor, antagonizes TRAIL-induced apoptosis in human myeloma cells.

J Clin Invest 2007 Oct;117(10):3107-17

Center for Hematology and Oncology Molecular Therapeutics, The Cleveland Clinic, Taussig Cancer Center, Cleveland, Ohio, USA.

The effectiveness of IFN-alpha2b for human multiple myeloma has been variable. TRAIL has been proposed to mediate IFN-alpha2b apoptosis in myeloma. In this study we assessed the effects of IFN-alpha2b signaling on the apoptotic activity of TRAIL and human myeloma cell survival. While TRAIL was one of the most potently induced proapoptotic genes in myeloma cells following IFN-alpha2b treatment, less than 20% of myeloma cells underwent apoptosis. Thus, we hypothesized that an IFN-stimulated gene (ISG) with prosurvival activity might suppress TRAIL-mediated apoptosis. Consistent with this, IFN-alpha2b stabilized mitochondria and inhibited caspase-3 activation, which antagonized TRAIL-mediated apoptosis and cytotoxicity after 24 hours of cotreatment in cell lines and in fresh myeloma cells, an effect not evident after 72 hours. Induced expression of G1P3, an ISG with largely unknown function, was correlated with the antiapoptotic activity of IFN-alpha2b. Ectopically expressed G1P3 localized to mitochondria and antagonized TRAIL-mediated mitochondrial potential loss, cytochrome c release, and apoptosis, suggesting specificity of G1P3 for the intrinsic apoptosis pathway. Furthermore, RNAi-mediated downregulation of G1P3 restored IFN-alpha2b-induced apoptosis. Our data identify the direct role of a mitochondria-localized prosurvival ISG in antagonizing the effect of TRAIL. Curtailing G1P3-mediated antiapoptotic signals could improve therapies for myeloma or other malignancies.
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http://dx.doi.org/10.1172/JCI31122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1964509PMC
October 2007

HDAC inhibitors: clinical update and mechanism-based potential.

Authors:
Keith B Glaser

Biochem Pharmacol 2007 Sep 7;74(5):659-71. Epub 2007 Apr 7.

Department of Cancer Research, R47J-AP9, Abbott Laboratories, Abbott Park, IL 60064-6121, USA.

Recently, the role of transcriptional repression through epigenetic modulation in carcinogenesis has been clinically validated with several inhibitors of histone deacetylases and DNA methyltransferases. It has long been recognized that epigenetic alterations of tumor suppressor genes was one of the contributing factors in carcinogenesis. Inhibitors of histone deacetylase (HDAC) de-repress genes that subsequently result in growth inhibition, differentiation and apoptosis of cancer cells. Vorinostat (SAHA), romidepsin (depsipeptide, FK-228), belinostat (PXD101) and LAQ824/LBH589 have demonstrated therapeutic benefit as monotherapy in cutaneous T-cell lymphoma (CTCL) and have also demonstrated some therapeutic benefit in other malignancies. The approval of the HDAC inhibitor vorinostat (Zolinzatrade mark) was based on the inherent sensitivity of this type of lymphoma to alterations in acetylation patterns that resulted in the induction of repressed apoptotic pathways. However, the full potential of these inhibitors (epigenetic modulators) is still on the horizon, as the true breadth of their utility as anti-cancer agents will be determined by the careful analysis of gene expression changes generated by these inhibitors and then combined with conventional chemotherapy to synergistically improve response and toxicity for an overall enhanced therapeutic benefit to the patient. The question that must be considered is whether the current HDACIs are being utilized to their fullest potential in clinical trials based on their mechanism-based alterations in disease processes.
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http://dx.doi.org/10.1016/j.bcp.2007.04.007DOI Listing
September 2007

Discovery of N-(4-(3-amino-1H-indazol-4-yl)phenyl)-N'-(2-fluoro-5-methylphenyl)urea (ABT-869), a 3-aminoindazole-based orally active multitargeted receptor tyrosine kinase inhibitor.

J Med Chem 2007 Apr 8;50(7):1584-97. Epub 2007 Mar 8.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois 60064-6100, USA.

In our continued efforts to search for potent and novel receptor tyrosine kinase (RTK) inhibitors as potential anticancer agents, we discovered, through a structure-based design, that 3-aminoindazole could serve as an efficient hinge-binding template for kinase inhibitors. By incorporating an N,N'-diaryl urea moiety at the C4-position of 3-aminodazole, a series of RTK inhibitors were generated, which potently inhibited the tyrosine kinase activity of the vascular endothelial growth factor receptor and the platelet-derived growth factor receptor families. A number of compounds with potent oral activity were identified by utilizing an estradiol-induced mouse uterine edema model and an HT1080 human fibrosarcoma xenograft tumor model. In particular, compound 17p (ABT-869) was found to possess favorable pharmacokinetic profiles across different species and display significant tumor growth inhibition in multiple preclinical animal models.
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http://dx.doi.org/10.1021/jm061280hDOI Listing
April 2007

ABT-869, a multitargeted receptor tyrosine kinase inhibitor: inhibition of FLT3 phosphorylation and signaling in acute myeloid leukemia.

Blood 2007 Apr 5;109(8):3400-8. Epub 2007 Jan 5.

Division of Hematology/Oncology, Department of Pediatrics, Gwynne Hazen Cherry Memorial Laboratories, David Geffen School of Medicine, University of California-Los Angeles, Los Angeles, CA, USA.

In 15% to 30% of patients with acute myeloid leukemia (AML), aberrant proliferation is a consequence of a juxtamembrane mutation in the FLT3 gene (FMS-like tyrosine kinase 3-internal tandem duplication [FLT3-ITD]), causing constitutive kinase activity. ABT-869 (a multitargeted receptor tyrosine kinase inhibitor) inhibited the phosphorylation of FLT3, STAT5, and ERK, as well as Pim-1 expression in MV-4-11 and MOLM-13 cells (IC(50) approximately 1-10 nM) harboring the FLT3-ITD. ABT-869 inhibited the proliferation of these cells (IC(50) = 4 and 6 nM, respectively) through the induction of apoptosis (increased sub-G(0)/G(1) phase, caspase activation, and PARP cleavage), whereas cells harboring wild-type (wt)-FLT3 were less sensitive. In normal human blood spiked with AML cells, ABT-869 inhibited phosphorylation of FLT3 (IC(50) approximately 100 nM), STAT5, and ERK, and decreased Pim-1 expression. In methylcellulose-based colony-forming assays, ABT-869 had no significant effect up to 1000 nM on normal hematopoietic progenitor cells, whereas in AML patient samples harboring both FLT3-ITD and wt-FLT3, ABT-869 inhibited colony formation (IC(50) = 100 and 1000 nM, respectively). ABT-869 dose-dependently inhibited MV-4-11 and MOLM-13 flank tumor growth, prevented tumor formation, regressed established MV-4-11 xenografts, and increased survival by 20 weeks in an MV-4-11 engraftment model. In tumors, ABT-869 inhibited FLT3 phosphorylation, induced apoptosis (transferase-mediated dUTP nick-end labeling [TUNEL]) and decreased proliferation (Ki67). ABT-869 is under clinical development for AML.
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http://dx.doi.org/10.1182/blood-2006-06-029579DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1852258PMC
April 2007

Thienopyridine urea inhibitors of KDR kinase.

Bioorg Med Chem Lett 2007 Mar 9;17(5):1246-9. Epub 2006 Dec 9.

Global Pharmaceutical Research and Development, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, IL 60064-6100, USA.

A series of substituted thienopyridine ureas was prepared and evaluated for enzymatic and cellular inhibition of KDR kinase activity. Several of these analogs, such as 2, are potent inhibitors of KDR (<10 nM) in both enzymatic and cellular assays. Further characterization of inhibitor 2 indicated that this analog possessed excellent in vivo potency (ED50 2.1 mg/kg) as measured in an estradiol-induced mouse uterine edema model.
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http://dx.doi.org/10.1016/j.bmcl.2006.12.015DOI Listing
March 2007

Isothiazolopyrimidines and isoxazolopyrimidines as novel multi-targeted inhibitors of receptor tyrosine kinases.

Bioorg Med Chem Lett 2006 Aug 2;16(16):4326-30. Epub 2006 Jun 2.

Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064-6100, USA.

A series of isothiazolopyrimidines and isoxazolopyrimidines were synthesized and identified as potent KDR inhibitors. SAR studies led to isothiazolopyrimidine urea analogs that potently inhibit VEGFR tyrosine kinases (KDR enzymatic and cellular IC(50) values below 10 nM) as well as cKIT and TIE2. The selected compounds 8 and 13 display 56% and 48% oral bioavailability in mice, respectively.
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http://dx.doi.org/10.1016/j.bmcl.2006.05.057DOI Listing
August 2006

Inhibition of phosphorylation of the colony-stimulating factor-1 receptor (c-Fms) tyrosine kinase in transfected cells by ABT-869 and other tyrosine kinase inhibitors.

Mol Cancer Ther 2006 Apr;5(4):1007-13

Cancer Discovery Research (R47J), Global Pharmaceutical Research and Development, Abbott Laboratories, Abbott Park, IL 60064-6121, USA.

The properties of several multitargeted receptor tyrosine kinase inhibitors have been studied for their inhibition of colony-stimulating factor-1 receptor (CSF-1R) signaling. A structurally novel, multitargeted tyrosine kinase inhibitor (ABT-869), imatinib (STI571), and four compounds currently in clinical development (AG013736, BAY 43-9006, CHIR258, and SU11248) were tested for inhibition of CSF-1R signaling in both the enzymatic and cellular assays. ABT-869 showed potent CSF-1R inhibition in both the enzyme and cell-based assays (IC50s < 20 nmol/L). In contrast to a previous report, we have found that imatinib has activity against human CSF-1R in both assays at submicromolar concentrations. In enzyme assays, we have found that the inhibition of CSF-1R by both ABT-869 and imatinib are competitive with ATP, with Ki values of 3 and 120 nmol/L, respectively. SU11248 is a potent inhibitor of CSF-1R in the enzyme assay (IC50 = 7 nmol/L) and inhibits receptor phosphorylation in the cellular assay (IC50 = 61 nmol/L). AG013736 was also a potent inhibitor of CSF-1R in both assays (enzyme, IC50 = 16 nmol/L; cellular, IC50 = 21 nmol/L), whereas BAY 43-9006 is less potent in the enzyme assay (IC50 = 107 nmol/L) than in the cellular system (IC50 = 20 nmol/L). In contrast, we found that CHIR258 had less activity in the cellular assay (IC50 = 535 nmol/L) relative to its enzymatic potency (IC50 = 26 nmol/L). These results show the use of a cell-based assay to confirm the inhibitory activity of lead compounds and drug candidates, such as ABT-869, against the CSF-1R protein in situ.
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http://dx.doi.org/10.1158/1535-7163.MCT-05-0359DOI Listing
April 2006
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