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1.
Mol Cancer Ther ; 12(2): 151-61, 2013 Feb.
Article in English | MEDLINE | ID: mdl-23270925

ABSTRACT

Dysregulation of the PI3K/mTOR pathway, either through amplifications, deletions, or as a direct result of mutations, has been closely linked to the development and progression of a wide range of cancers. Moreover, this pathway activation is a poor prognostic marker for many tumor types and confers resistance to various cancer therapies. Here, we describe VS-5584, a novel, low-molecular weight compound with equivalent potent activity against mTOR (IC(50) = 37 nmol/L) and all class I phosphoinositide 3-kinase (PI3K) isoforms IC(50): PI3Kα = 16 nmol/L; PI3Kß = 68 nmol/L; PI3Kγ = 25 nmol/L; PI3Kδ = 42 nmol/L, without relevant activity on 400 lipid and protein kinases. VS-5584 shows robust modulation of cellular PI3K/mTOR pathways, inhibiting phosphorylation of substrates downstream of PI3K and mTORC1/2. A large human cancer cell line panel screen (436 lines) revealed broad antiproliferative sensitivity and that cells harboring mutations in PI3KCA are generally more sensitive toward VS-5584 treatment. VS-5584 exhibits favorable pharmacokinetic properties after oral dosing in mice and is well tolerated. VS-5584 induces long-lasting and dose-dependent inhibition of PI3K/mTOR signaling in tumor tissue, leading to tumor growth inhibition in various rapalog-sensitive and -resistant human xenograft models. Furthermore, VS-5584 is synergistic with an EGF receptor inhibitor in a gastric tumor model. The unique selectivity profile and favorable pharmacologic and pharmaceutical properties of VS-5584 and its efficacy in a wide range of human tumor models supports further investigations of VS-5584 in clinical trials.


Subject(s)
Morpholines/pharmacology , Neoplasms/drug therapy , Phosphoinositide-3 Kinase Inhibitors , Protein Kinase Inhibitors/pharmacology , Purines/pharmacology , TOR Serine-Threonine Kinases/antagonists & inhibitors , Animals , Cell Line, Tumor , Cell Proliferation/drug effects , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/enzymology , Disease Models, Animal , Female , Gastrointestinal Neoplasms/drug therapy , Gastrointestinal Neoplasms/enzymology , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Mice, SCID , Morpholines/adverse effects , Morpholines/pharmacokinetics , Neoplasms/enzymology , PTEN Phosphohydrolase/deficiency , Prostatic Neoplasms/drug therapy , Prostatic Neoplasms/enzymology , Protein Kinase Inhibitors/adverse effects , Protein Kinase Inhibitors/pharmacokinetics , Purines/adverse effects , Purines/pharmacokinetics , Signal Transduction , Xenograft Model Antitumor Assays
2.
J Immunol ; 189(8): 4123-34, 2012 Oct 15.
Article in English | MEDLINE | ID: mdl-22962687

ABSTRACT

SB1578 is a novel, orally bioavailable JAK2 inhibitor with specificity for JAK2 within the JAK family and also potent activity against FLT3 and c-Fms. These three tyrosine kinases play a pivotal role in activation of pathways that underlie the pathogenesis of rheumatoid arthritis. SB1578 blocks the activation of these kinases and their downstream signaling in pertinent cells, leading to inhibition of pathological cellular responses. The biochemical and cellular activities of SB1578 translate into its high efficacy in two rodent models of arthritis. SB1578 not only prevents the onset of arthritis but is also potent in treating established disease in collagen-induced arthritis mice with beneficial effects on histopathological parameters of bone resorption and cartilage damage. SB1578 abrogates the inflammatory response and prevents the infiltration of macrophages and neutrophils into affected joints. It also leads to inhibition of Ag-presenting dendritic cells and inhibits the autoimmune component of the disease. In summary, SB1578 has a unique kinase spectrum, and its pharmacological profile provides a strong rationale for the ongoing clinical development in autoimmune diseases.


Subject(s)
Arthritis, Experimental/drug therapy , Arthritis, Experimental/immunology , Heterocyclic Compounds, 4 or More Rings/administration & dosage , Janus Kinase 2/antagonists & inhibitors , Receptor, Macrophage Colony-Stimulating Factor/antagonists & inhibitors , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Animals , Arthritis, Experimental/pathology , Arthritis, Rheumatoid/drug therapy , Arthritis, Rheumatoid/immunology , Arthritis, Rheumatoid/pathology , Disease Models, Animal , Heterocyclic Compounds, 4 or More Rings/therapeutic use , Male , Mice , Mice, Inbred C57BL , Rats , Rats, Inbred Lew
3.
Bioorg Med Chem Lett ; 22(8): 2880-4, 2012 Apr 15.
Article in English | MEDLINE | ID: mdl-22437109

ABSTRACT

A series of 2-anilino substituted 4-aryl-8H-purines were prepared as potent inhibitors of PDK1, a serine-threonine kinase thought to play a role in the PI3K/Akt signaling pathway, a key mediator of cancer cell growth, survival and tumorigenesis. The synthesis, SAR and ADME properties of this series of compounds are discussed culminating in the discovery of compound 6 which possessed sub-micromolar cell proliferation activity and 65% oral bioavailability in mice.


Subject(s)
Aniline Compounds/chemistry , Protein Serine-Threonine Kinases/antagonists & inhibitors , Purines/chemistry , Small Molecule Libraries/chemistry , Aniline Compounds/pharmacology , Animals , Cell Line, Tumor , Cells, Cultured , Enzyme Activation/drug effects , Enzyme Inhibitors/pharmacology , Humans , Inhibitory Concentration 50 , Mice , Molecular Structure , Purines/pharmacology , Pyruvate Dehydrogenase Acetyl-Transferring Kinase , Small Molecule Libraries/pharmacology , Solubility
4.
J Med Chem ; 55(6): 2623-40, 2012 Mar 22.
Article in English | MEDLINE | ID: mdl-22339472

ABSTRACT

Herein, we describe the synthesis and SAR of a series of small molecule macrocycles that selectively inhibit JAK2 kinase within the JAK family and FLT3 kinase. Following a multiparameter optimization of a key aryl ring of the previously described SB1518 (pacritinib), the highly soluble 14l was selected as the optimal compound. Oral efficacy in the murine collagen-induced arthritis (CIA) model for rheumatoid arthritis (RA) supported 14l as a potential treatment for autoimmune diseases and inflammatory disorders such as psoriasis and RA. Compound 14l (SB1578) was progressed into development and is currently undergoing phase 1 clinical trials in healthy volunteers.


Subject(s)
Antirheumatic Agents/chemical synthesis , Arthritis, Rheumatoid/drug therapy , Heterocyclic Compounds, 4 or More Rings/chemical synthesis , Janus Kinase 2/antagonists & inhibitors , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Animals , Antirheumatic Agents/pharmacokinetics , Antirheumatic Agents/pharmacology , Arthritis, Experimental/chemically induced , Arthritis, Experimental/drug therapy , Cell Line , Cell Membrane Permeability , Collagen Type II , Dogs , Female , Heterocyclic Compounds, 4 or More Rings/pharmacokinetics , Heterocyclic Compounds, 4 or More Rings/pharmacology , Humans , Janus Kinase 2/physiology , Macaca mulatta , Male , Mice , Mice, Nude , Microsomes/metabolism , Models, Molecular , Rats , Signal Transduction/drug effects , Solubility , Stereoisomerism , Structure-Activity Relationship , TYK2 Kinase/antagonists & inhibitors
5.
J Med Chem ; 55(1): 169-96, 2012 Jan 12.
Article in English | MEDLINE | ID: mdl-22148278

ABSTRACT

Herein, we describe the design, synthesis, and SAR of a series of unique small molecule macrocycles that show spectrum selective kinase inhibition of CDKs, JAK2, and FLT3. The most promising leads were assessed in vitro for their inhibition of cancer cell proliferation, solubility, CYP450 inhibition, and microsomal stability. This screening cascade revealed 26 h as a preferred compound with target IC(50) of 13, 73, and 56 nM for CDK2, JAK2 and FLT3, respectively. Pharmacokinetic (PK) studies of 26 h in preclinical species showed good oral exposures. Oral efficacy was observed in colon (HCT-116) and lymphoma (Ramos) xenograft studies, in line with the observed PK/PD correlation. 26h (SB1317/TG02) was progressed into development in 2010 and is currently undergoing phase 1 clinical trials in advanced leukemias and multiple myeloma.


Subject(s)
Antineoplastic Agents/chemical synthesis , Cyclin-Dependent Kinases/antagonists & inhibitors , Heterocyclic Compounds, 4 or More Rings/chemical synthesis , Janus Kinase 3/antagonists & inhibitors , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Administration, Oral , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Cell Line, Tumor , Cell Proliferation/drug effects , Computer Simulation , Dogs , Drug Screening Assays, Antitumor , Female , Heterocyclic Compounds, 4 or More Rings/pharmacokinetics , Heterocyclic Compounds, 4 or More Rings/pharmacology , Humans , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Microsomes, Liver/metabolism , Models, Molecular , Neoplasm Transplantation , Rats , Stereoisomerism , Structure-Activity Relationship , Transplantation, Heterologous
6.
J Med Chem ; 54(13): 4694-720, 2011 Jul 14.
Article in English | MEDLINE | ID: mdl-21634430

ABSTRACT

A series of 3-(1,2-disubstituted-1H-benzimidazol-5-yl)-N-hydroxyacrylamides (1) were designed and synthesized as HDAC inhibitors. Extensive SARs have been established for in vitro potency (HDAC1 enzyme and COLO 205 cellular IC(50)), liver microsomal stability (t(1/2)), cytochrome P450 inhibitory (3A4 IC(50)), and clogP, among others. These parameters were fine-tuned by carefully adjusting the substituents at positions 1 and 2 of the benzimidazole ring. After comprehensive in vitro and in vivo profiling of the selected compounds, SB939 (3) was identified as a preclinical development candidate. 3 is a potent pan-HDAC inhibitor with excellent druglike properties, is highly efficacious in in vivo tumor models (HCT-116, PC-3, A2780, MV4-11, Ramos), and has high and dose-proportional oral exposures and very good ADME, safety, and pharmaceutical properties. When orally dosed to tumor-bearing mice, 3 is enriched in tumor tissue which may contribute to its potent antitumor activity and prolonged duration of action. 3 is currently being tested in phase I and phase II clinical trials.


Subject(s)
Antineoplastic Agents/chemical synthesis , Benzimidazoles/chemical synthesis , Histone Deacetylase Inhibitors/chemical synthesis , Administration, Oral , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Benzimidazoles/pharmacokinetics , Benzimidazoles/pharmacology , Biological Availability , Cell Line, Tumor , Dogs , Drug Screening Assays, Antitumor , Female , Histone Deacetylase 1/antagonists & inhibitors , Histone Deacetylase Inhibitors/pharmacokinetics , Histone Deacetylase Inhibitors/pharmacology , Humans , Isoenzymes/antagonists & inhibitors , Isoenzymes/metabolism , Mice , Mice, Inbred BALB C , Mice, Nude , Microsomes, Liver/metabolism , Neoplasm Transplantation , Quantitative Structure-Activity Relationship , Rats , Rats, Wistar , Stereoisomerism
7.
J Med Chem ; 54(13): 4638-58, 2011 Jul 14.
Article in English | MEDLINE | ID: mdl-21604762

ABSTRACT

Discovery of the activating mutation V617F in Janus Kinase 2 (JAK2(V617F)), a tyrosine kinase critically involved in receptor signaling, recently ignited interest in JAK2 inhibitor therapy as a treatment for myelofibrosis (MF). Herein, we describe the design and synthesis of a series of small molecule 4-aryl-2-aminopyrimidine macrocycles and their biological evaluation against the JAK family of kinase enzymes and FLT3. The most promising leads were assessed for their in vitro ADME properties culminating in the discovery of 21c, a potent JAK2 (IC(50) = 23 and 19 nM for JAK2(WT) and JAK2(V617F), respectively) and FLT3 (IC(50) = 22 nM) inhibitor with selectivity against JAK1 and JAK3 (IC(50) = 1280 and 520 nM, respectively). Further profiling of 21c in preclinical species and mouse xenograft and allograft models is described. Compound 21c (SB1518) was selected as a development candidate and progressed into clinical trials where it is currently in phase 2 for MF and lymphoma.


Subject(s)
Antineoplastic Agents/chemical synthesis , Bridged-Ring Compounds/chemical synthesis , Janus Kinase 2/antagonists & inhibitors , Lymphoma/drug therapy , Primary Myelofibrosis/drug therapy , Pyrimidines/chemical synthesis , fms-Like Tyrosine Kinase 3/antagonists & inhibitors , Adenosine Triphosphate/chemistry , Animals , Antineoplastic Agents/pharmacokinetics , Antineoplastic Agents/pharmacology , Binding Sites , Bridged-Ring Compounds/pharmacokinetics , Bridged-Ring Compounds/pharmacology , Cell Line, Tumor , Dogs , Drug Screening Assays, Antitumor , Humans , In Vitro Techniques , Mice , Mice, Nude , Microsomes, Liver/metabolism , Models, Molecular , Neoplasm Transplantation , Pyrimidines/pharmacokinetics , Pyrimidines/pharmacology , Rats , Solubility , Transplantation, Heterologous , Transplantation, Homologous
8.
Cancer Chemother Pharmacol ; 67(1): 193-200, 2011 Jan.
Article in English | MEDLINE | ID: mdl-20512579

ABSTRACT

PURPOSE: Everolimus (RAD001, Afinitor) is an mTORC1 pathway inhibitor, and vatalanib (PTK/ZK) is a pan VEGF-R tyrosine kinase inhibitor (TKI). These two drugs have been shown to have overlapping but also distinct anti-angiogenic effects. Consequently, we investigated the pharmacokinetics (PK) and pharmacodynamics (PD) of their combination in vivo. METHODS: Murine melanoma B16/BL6 cells were grown orthotopically in BL6/C57 mice by injection into the derma of both ears to create a primary tumour which metastasized rapidly to the cervical lymph nodes. Mice were treated daily p.o. with PTK/ZK (100 mg/kg) or everolimus (1 mg/kg) or their combination, and anti-tumour efficacy (PD) assessed. In the same model, plasma PK of everolimus was measured following single doses of the monotherapy or combination schedules. RESULTS: Two independent experiments showed that combination of everolimus and PTK/ZK caused at least additive increases in anti-tumour activity compared to either monotherapy, without increases in toxicity. Pooling the data to improve the statistical power demonstrated the interactions to be synergistic. PK modelling showed that although PTK/ZK increased everolimus plasma concentrations by about twofold, this PK drug-drug interaction could not account for the increased anti-tumour effect of the combination. Modelling of the PTK/ZK dose-response curve in this model suggested that any effect of everolimus on the PK of PTK/ZK was unlikely to affect efficacy. Measurement of changes in tumour and plasma VEGF levels at the endpoint of therapy confirmed earlier observations of differential effects of these two agents. CONCLUSIONS: The combination of everolimus and PTK/ZK hold promise for the treatment of human cancers.


Subject(s)
Antineoplastic Combined Chemotherapy Protocols/pharmacology , Melanoma, Experimental/drug therapy , Models, Biological , Angiogenesis Inhibitors/administration & dosage , Angiogenesis Inhibitors/pharmacokinetics , Angiogenesis Inhibitors/pharmacology , Animals , Antineoplastic Combined Chemotherapy Protocols/administration & dosage , Antineoplastic Combined Chemotherapy Protocols/pharmacokinetics , Cell Line, Tumor , Dose-Response Relationship, Drug , Drug Synergism , Everolimus , Female , Mechanistic Target of Rapamycin Complex 1 , Melanoma, Experimental/pathology , Mice , Mice, Inbred C57BL , Multiprotein Complexes , Neoplasm Metastasis , Phthalazines/administration & dosage , Proteins/antagonists & inhibitors , Pyridines/administration & dosage , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Sirolimus/administration & dosage , Sirolimus/analogs & derivatives , TOR Serine-Threonine Kinases
9.
Angiogenesis ; 13(3): 259-67, 2010 Sep.
Article in English | MEDLINE | ID: mdl-20803239

ABSTRACT

EphB4 and its cognitive ligand ephrinB2 play an important role in embryonic vessel development and vascular remodeling. In addition, several reports suggest that this receptor ligand pair is also involved in pathologic vessel formation in adults including tumor angiogenesis. Eph/ephrin signaling is a complex phenomena characterized by receptor forward signaling through the tyrosine kinase of the receptor and ephrin reverse signaling through various protein-protein interaction domains and phosphorylation motifs of the ephrin ligands. Therefore, interfering with EphR/ephrin signaling by the means of targeted gene ablation, soluble receptors, dominant negative mutants or antisense molecules often does not allow to discriminate between inhibition of Eph/ephrin forward and reverse signaling. We developed a specific small molecular weight kinase inhibitor of the EphB4 kinase, NVP-BHG712, which inhibits EphB4 kinase activity in the low nanomolar range in cellular assays showed high selectivity for targeting the EphB4 kinase when profiled against other kinases in biochemical as well as in cell based assays. Furthermore, NVP-BHG712 shows excellent pharmacokinetic properties and potently inhibits EphB4 autophosphorylation in tissues after oral administration. In vivo, NVP-BHG712 inhibits VEGF driven vessel formation, while it has only little effects on VEGF receptor (VEGFR) activity in vitro or in cellular assays. The data shown here suggest a close cross talk between the VEGFR and EphR signaling during vessel formation. In addition to its established function in vascular remodeling and endothelial arterio-venous differentiation, EphB4 forward signaling appears to be an important mediator of VEGF induced angiogenesis since inhibition of EphB4 forward signaling is sufficient to inhibit VEGF induced angiogenesis.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Angiogenesis Inhibitors/therapeutic use , Neovascularization, Pathologic/drug therapy , Protein Kinase Inhibitors/pharmacology , Pyrazoles/pharmacology , Pyrazoles/therapeutic use , Pyrimidines/pharmacology , Pyrimidines/therapeutic use , Receptor, EphB4/antagonists & inhibitors , Small Molecule Libraries/pharmacology , Vascular Endothelial Growth Factor A/metabolism , Angiogenesis Inhibitors/chemistry , Angiogenesis Inhibitors/pharmacokinetics , Animals , Biological Assay , Humans , Lung/drug effects , Lung/metabolism , Mice , Neovascularization, Pathologic/enzymology , Organ Size/drug effects , Phosphorylation/drug effects , Protein Kinase Inhibitors/chemistry , Protein Kinase Inhibitors/pharmacokinetics , Pyrazoles/chemistry , Pyrazoles/pharmacokinetics , Pyrimidines/chemistry , Pyrimidines/pharmacokinetics , Receptor, EphB4/metabolism , Signal Transduction/drug effects , Solubility/drug effects
10.
Bioorg Med Chem Lett ; 19(16): 4863-7, 2009 Aug 15.
Article in English | MEDLINE | ID: mdl-19615901

ABSTRACT

Novel nonpeptide small molecule renin inhibitors bearing an N-isopropyl P(1) motif were designed based on initial lead structures 1 and aliskiren (2). (P(3)-P(1))-Benzamide derivatives such as 9a and 34, as well as the corresponding P(1) basic tertiary amine derivatives 10 and 35 were found to display low nanomolar inhibition against human renin in vitro.


Subject(s)
Amides/chemistry , Antihypertensive Agents/chemistry , Benzamides/chemistry , Ethylenes/chemistry , Fumarates/chemistry , Protease Inhibitors/chemistry , Renin/antagonists & inhibitors , Administration, Oral , Animals , Antihypertensive Agents/chemical synthesis , Antihypertensive Agents/pharmacology , Benzamides/chemical synthesis , Benzamides/pharmacology , Callithrix , Humans , Protease Inhibitors/chemical synthesis , Protease Inhibitors/pharmacology , Renin/metabolism , Stereoisomerism , Structure-Activity Relationship
11.
Clin Cancer Res ; 15(5): 1612-22, 2009 Mar 01.
Article in English | MEDLINE | ID: mdl-19223496

ABSTRACT

PURPOSE: Comparison of the antiangiogenic/vascular properties of the oral mammalian target of rapamycin (mTOR) inhibitor RAD001 (everolimus) and the vascular endothelial growth factor receptor (VEGFR) inhibitor vatalanib (PTK/ZK). EXPERIMENTAL DESIGN: Antiproliferative activity against various tumor histotypes and downstream effects on the mTOR pathway were measured in vitro. In vivo, antitumor activity, plasma, and tumor RAD001 levels were measured. Activity in several different angiogenic/vascular assays in vitro and in vivo was assessed and compared with PTK/ZK. RESULTS: RAD001 inhibited proliferation in vitro (IC50 values<1 nmol/L to >1 micromol/L), and in sensitive and insensitive tumor cells, pS6 kinase and 4E-BP1 were inhibited. Activity in vitro did not correlate with activity in vivo and significant responses were seen in tumors with IC50 values>10-fold higher than tumor RAD001 concentrations. In vitro, RAD001 inhibited the proliferation of VEGF-stimulated and fibroblast growth factor-stimulated human endothelial cells but not dermal fibroblasts and impaired VEGF release from both sensitive and insensitive tumor cells but did not inhibit migration of human endothelial cells. In vivo, in tumor models derived from either sensitive or insensitive cells, RAD001 reduced Tie-2 levels, the amount of mature and immature vessels, total plasma, and tumor VEGF. RAD001 did not affect blood vessel leakiness in normal vasculature acutely exposed to VEGF nor did it affect tumor vascular permeability (Ktrans) as measured by dynamic contrast-enhanced magnetic resonance imaging. However, the pan-VEGFR inhibitor PTK/ZK inhibited endothelial cell migration and vascular permeability but had less effect on mature vessels compared with RAD001. CONCLUSIONS: VEGFR and mTOR inhibitors show similar but also distinct effects on tumor vascular biology, which has implications for their clinical activity alone or in combination.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Neoplasms, Experimental/blood supply , Neovascularization, Pathologic/drug therapy , Phthalazines/pharmacology , Protein Kinase Inhibitors/pharmacology , Protein Kinases/chemistry , Pyridines/pharmacology , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Sirolimus/analogs & derivatives , Angiogenesis Inhibitors/pharmacokinetics , Animals , Cell Movement/drug effects , Cell Proliferation/drug effects , Everolimus , Female , Humans , Immunoenzyme Techniques , Magnetic Resonance Imaging , Mice , Mice, Inbred BALB C , Mice, Inbred C57BL , Neoplasms, Experimental/drug therapy , Neoplasms, Experimental/metabolism , Phthalazines/pharmacokinetics , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinases/metabolism , Pyridines/pharmacokinetics , Rats , Rats, Inbred BN , Rats, Inbred WF , Receptor, TIE-2/metabolism , Receptors, Vascular Endothelial Growth Factor/metabolism , Sirolimus/pharmacokinetics , Sirolimus/pharmacology , TOR Serine-Threonine Kinases , Tissue Distribution , Transplantation, Heterologous , Vascular Endothelial Growth Factor A/metabolism
12.
J Med Chem ; 50(20): 4818-31, 2007 Oct 04.
Article in English | MEDLINE | ID: mdl-17824679

ABSTRACT

The action of renin is the rate-limiting step of the renin-angiotensin system (RAS), a key regulator of blood pressure. Effective renin inhibitors directly block the RAS entirely at source and, thus, may provide a vital weapon for hypertension therapy. Our efforts toward identifying novel small-molecule peptidomimetic renin inhibitors have resulted in the design of transition-state isosteres such as 1 bearing an all-carbon 8-phenyl-octanecarboxamide framework. Optimization of the extended P3 portion of 1 and extensive P2' modifications provided analogues with improved in vitro potencies in the presence of plasma. X-ray resolution of rh-renin/38a in the course of SAR work surprisingly unveiled the exploitation of a previously unexplored pocket (S3sp) important for strong binding affinities. Several inhibitors demonstrated oral efficacy in sodium-depleted marmosets. The most potent, 38a, induced dose-dependently a pronounced reduction in mean arterial blood pressure, paralleled by complete blockade of active plasma renin, up to 8 h post-dose. Oral bioavailability of 38a was 16% in marmosets.


Subject(s)
Amides/chemical synthesis , Anisoles/chemical synthesis , Antihypertensive Agents/chemical synthesis , Caprylates/chemical synthesis , Peptides/chemistry , Renin/antagonists & inhibitors , Administration, Oral , Amides/chemistry , Amides/pharmacology , Animals , Anisoles/chemistry , Anisoles/pharmacology , Antihypertensive Agents/chemistry , Antihypertensive Agents/pharmacology , Biological Availability , Blood Pressure/drug effects , Callithrix , Caprylates/chemistry , Caprylates/pharmacology , Crystallography, X-Ray , Heart Rate/drug effects , Humans , Kinetics , Models, Molecular , Molecular Mimicry , Molecular Structure , Protein Binding , Renin/blood , Stereoisomerism , Structure-Activity Relationship
13.
J Med Chem ; 50(20): 4832-44, 2007 Oct 04.
Article in English | MEDLINE | ID: mdl-17824680

ABSTRACT

Due to its function in the rate limiting initial step of the renin-angiotensin system, renin is a particularly promising target for drugs designed to control hypertension, a growing risk to health worldwide. Despite vast efforts over more than two decades, no orally efficacious renin inhibitor had reached the market. As a result of a structure-based topological design approach, we have identified a novel class of small-molecule inhibitors with good oral blood-pressure lowering effects in primates. Further lead optimization aimed for improvement of in vivo potency and duration of action, mainly by P2' modifications at the hydroxyethylene transition-state isostere. These efforts resulted in the discovery of aliskiren (46, CGP060536B, SPP100), a highly potent, selective inhibitor of renin, demonstrating excellent efficacy in sodium-depleted marmosets after oral administration, with sustained duration of action in reducing dose-dependently mean arterial blood pressure. Aliskiren has recently received regulatory approval by the U.S. Food and Drug Administration for the treatment of hypertension.


Subject(s)
Amides/chemical synthesis , Antihypertensive Agents/chemical synthesis , Caprylates/chemical synthesis , Fumarates/chemical synthesis , Renin/antagonists & inhibitors , Administration, Oral , Amides/chemistry , Amides/pharmacology , Animals , Antihypertensive Agents/chemistry , Antihypertensive Agents/pharmacology , Blood Pressure/drug effects , Callithrix , Caprylates/chemistry , Caprylates/pharmacology , Crystallography, X-Ray , Fumarates/chemistry , Fumarates/pharmacology , Heart Rate/drug effects , Humans , Kinetics , Models, Molecular , Molecular Structure , Protein Binding , Renin/blood , Stereoisomerism , Structure-Activity Relationship
14.
Nat Chem Biol ; 2(5): 265-73, 2006 May.
Article in English | MEDLINE | ID: mdl-16565716

ABSTRACT

We examined the role of angiogenesis and the need for receptor signaling using chemical inhibition of the vascular endothelial growth factor receptor in the adult zebrafish tail fin. Using a small-molecule inhibitor, we were able to exert precise control over blood vessel regeneration. An angiogenic limit to tissue regeneration was determined, as avascular tissue containing skin, pigment, neuronal axons and bone precursors could regenerate up to about 1 mm. This indicates that tissues can regenerate without direct interaction with endothelial cells and at a distance from blood supply. We also investigated whether the effects of chemical inhibition could be enhanced in zebrafish vascular mutants. We found that adult zebrafish, heterozygous for a mutation in the critical receptor effector phospholipase Cgamma1, show a greater sensitivity to chemical inhibition. This study illustrates the utility of the adult zebrafish as a new model system for receptor signaling and chemical biology.


Subject(s)
Angiogenesis Inhibitors/pharmacology , Endothelial Cells/drug effects , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Regeneration/drug effects , Zebrafish/physiology , Animals , Axons/drug effects , Axons/physiology , Bone Regeneration/drug effects , Bone Regeneration/physiology , Endothelial Cells/physiology , Guided Tissue Regeneration/methods , Heterozygote , Microscopy, Fluorescence , Mutation , Neurons/metabolism , Phospholipase C gamma/pharmacology , Pigment Epithelium of Eye/drug effects , Pigment Epithelium of Eye/physiology , Receptors, Vascular Endothelial Growth Factor/metabolism , Regeneration/physiology , Skin Physiological Phenomena/drug effects , Tissue Engineering
15.
J Hypertens ; 23(2): 417-26, 2005 Feb.
Article in English | MEDLINE | ID: mdl-15662231

ABSTRACT

OBJECTIVES: Aliskiren is a new renin inhibitor of a novel structural class that has recently been shown to be efficacious in hypertensive patients after once-daily oral dosing. We report the results of animal experiments performed in marmosets and rats in order to characterize aliskiren before its recent investigation in humans. METHODS: The effects of aliskiren were investigated in sodium-depleted marmosets (oral dosing) and in spontaneously hypertensive rats (dosing via subcutaneous osmotic minipumps). Blood pressure (BP) and heart rate were measured by radiotelemetry. RESULTS: In sodium-depleted marmosets, single oral doses of aliskiren (1-30 mg/kg) dose-dependently lowered BP. At a dose of 3 mg/kg, peak effects were observed 1 h after dosing (-30 +/- 4 mmHg, n = 6) and the response persisted for more than 12 h. A single oral dose of 3 mg/kg aliskiren was more effective than the same dose of either remikiren or zankiren, two orally active renin inhibitors previously tested in humans. Aliskiren (10 mg/kg) was at least as effective as equal doses of the AT1-receptor blocker valsartan or the angiotensin-converting enzyme inhibitor benazepril. In spontaneously hypertensive rats, aliskiren dose-dependently (10-100 mg/kg per day) decreased BP. Aliskiren also potentiated the antihypertensive effects of low doses of valsartan or benazeprilat (1 or 3 mg/kg per day). CONCLUSIONS: Aliskiren is an orally effective, long-lasting renin inhibitor that shows antihypertensive efficacy in animals superior to previous renin inhibitors and at least equivalent to angiotensin-converting enzyme inhibitors and AT1-receptor blockers. Aliskiren may therefore represent an effective, novel approach to the treatment of hypertension and related disorders, alone or in combination with other antihypertensive agents.


Subject(s)
Blood Pressure/drug effects , Fumarates/administration & dosage , Fumarates/pharmacology , Fumarates/pharmacokinetics , Renin/antagonists & inhibitors , Valine/analogs & derivatives , Administration, Oral , Amides , Angiotensin II Type 1 Receptor Blockers/pharmacology , Angiotensin-Converting Enzyme Inhibitors/pharmacology , Animals , Benzazepines/pharmacology , Callithrix , Dose-Response Relationship, Drug , Drug Evaluation, Preclinical , Drug Interactions , Female , Heart Rate/drug effects , Imidazoles/pharmacology , Injections, Intravenous , Male , Piperazines/pharmacology , Rats , Rats, Inbred SHR , Renin/blood , Telemetry , Tetrazoles/pharmacology , Thiazoles/pharmacology , Valine/pharmacology , Valsartan
16.
Biochem Biophys Res Commun ; 308(4): 698-705, 2003 Sep 05.
Article in English | MEDLINE | ID: mdl-12927775

ABSTRACT

Hypertension is a major risk factor for cardiovascular diseases such as stroke, myocardial infarction, and heart failure, the leading causes of death in the Western world. Inhibitors of the renin-angiotensin system (RAS) have proven to be successful treatments for hypertension. As renin specifically catalyses the rate-limiting step of the RAS, it represents the optimal target for RAS inhibition. Several peptide-like renin inhibitors have been synthesized previously, but poor pharmacokinetic properties meant that these compounds were not clinically useful. We employed a combination of molecular modelling and crystallographic structure analysis to design renin inhibitors lacking the extended peptide-like backbone of earlier inhibitors, for improved pharmacokinetic properties. This led to the discovery of aliskiren, a highly potent and selective inhibitor of human renin in vitro, and in vivo; once-daily oral doses of aliskiren inhibit renin and lower blood pressure in sodium-depleted marmosets and hypertensive human patients. Aliskiren represents the first in a novel class of renin inhibitors with the potential for treatment of hypertension and related cardiovascular diseases.


Subject(s)
Drug Design , Fumarates/chemistry , Fumarates/pharmacology , Hypertension/drug therapy , Renin/antagonists & inhibitors , Administration, Oral , Adolescent , Adult , Aged , Amides , Animals , Blood Pressure , Crystallography, X-Ray , Humans , Hydrogen-Ion Concentration , Inhibitory Concentration 50 , Middle Aged , Models, Chemical , Models, Molecular , Peptides/chemistry , Renin/blood , Renin/chemistry , Renin-Angiotensin System/drug effects , Sodium/metabolism , Species Specificity , Time Factors
17.
Eur J Nucl Med Mol Imaging ; 30(3): 448-55, 2003 Mar.
Article in English | MEDLINE | ID: mdl-12722742

ABSTRACT

The aim of this study was to evaluate the potential of dynamic magnetic resonance imaging (MRI) enhanced by macromolecular contrast agents to monitor noninvasively the therapeutic effect of an anti-angiogenesis VEGF receptor kinase inhibitor in an experimental cancer model. MDA-MB-435, a poorly differentiated human breast cancer cell line, was implanted into the mammary fat pad in 20 female homozygous athymic rats. Animals were assigned randomly to a control (n=10) or drug treatment group (n=10). Baseline dynamic MRI was performed on sequential days using albumin-(GdDTPA)30 (6.0 nm diameter) and ultrasmall superparamagnetic iron oxide (USPIO) particles (approximately 30 nm diameter). Subjects were treated either with PTK787/ZK 222584, a VEGF receptor tyrosine kinase inhibitor, or saline given orally twice daily for 1 week followed by repeat MRI examinations serially using each contrast agent. Employing a unidirectional kinetic model comprising the plasma and interstitial water compartments, tumor microvessel characteristics including fractional plasma volume and transendothelial permeability (K(PS)) were estimated for each contrast medium. Tumor growth and the microvascular density, a histologic surrogate of angiogenesis, were also measured. Control tumors significantly increased (P<0.05) in size and in microvascular permeability (K(PS)) based on MRI assays using both macromolecular contrast media. In contrast, tumor growth was significantly reduced (P<0.05) in rats treated with PTK787/ZK 222584 and K(PS) values declined slightly. Estimated values for the fractional plasma volume did not differ significantly between treatment groups or contrast agents. Microvascular density counts correlated fairly with the tumor growth rate (r=0.64) and were statistically significant higher (P<0.05) in the control than in the drug-treated group. MRI measurements of tumor microvascular response, particularly transendothelial permeability (K(PS)), using either of two macromolecular contrast media, were able to detect effects of treatment with a VEGF receptor tyrosine kinase inhibitor on tumor vascular permeability. In a clinical setting such quantitative MRI measurements could be used to monitor tumor anti-angiogenesis therapy.


Subject(s)
Breast Neoplasms/blood supply , Breast Neoplasms/diagnosis , Magnetic Resonance Imaging/methods , Neovascularization, Pathologic/diagnosis , Neovascularization, Pathologic/drug therapy , Phthalazines/therapeutic use , Pyridines , Angiogenesis Inhibitors/therapeutic use , Animals , Endothelium, Vascular/drug effects , Endothelium, Vascular/pathology , Female , Humans , Neoplasm Transplantation , Predictive Value of Tests , Rats , Treatment Outcome
18.
Arterioscler Thromb Vasc Biol ; 23(1): 69-75, 2003 Jan 01.
Article in English | MEDLINE | ID: mdl-12524227

ABSTRACT

OBJECTIVE: Hepatocyte growth factor/scatter factor (HGF/SF) promotes vascular endothelial growth factor (VEGF) expression and induces angiogenesis in multiple pathological conditions. The present study was designed to delineate the HGF/SF and VEGF signaling cascades during angiogenesis by using PTK787, a selective VEGF receptor antagonist. METHODS AND RESULTS: PTK787 produced a concentration-dependent (10(-8) to 10(-6) mol/L) inhibition of VEGF-induced angiogenesis, without altering the basal or HGF/SF-induced response in vitro. In contrast, the nonspecific kinase inhibitor genistein blocked the HGF/SF-induced effect. Both VEGF and HGF/SF induced a rapid phosphorylation of extracellular receptor kinases-1 and -2 (ERKs) and Akt. PTK787 inhibited the VEGF-induced activation of Akt and ERKs, without affecting the HGF/SF-induced phosphorylation. Treatment with VEGF and HGF/SF increased total neovascularization in a murine scaffold granuloma model, but no additive or synergistic interactions were observed. PTK787 (50 mg/kg) blocked the VEGF-induced response without altering the basal or HGF/SF-induced neovascularization. CONCLUSIONS: We demonstrate that HGF/SF can induce angiogenesis independently of VEGF, possibly through the direct activation of the Akt and ERKs. These results demonstrate the necessity of a multitargeted approach for the rational design of newer therapies to inhibit pathophysiological angiogenesis.


Subject(s)
Endothelial Growth Factors/physiology , Hepatocyte Growth Factor/physiology , Intercellular Signaling Peptides and Proteins/physiology , Lymphokines/physiology , Neovascularization, Pathologic/physiopathology , Proto-Oncogene Proteins , Pyridines , Animals , Cell Division/drug effects , Cell Division/physiology , Cells, Cultured , Endothelial Growth Factors/antagonists & inhibitors , Endothelial Growth Factors/biosynthesis , Endothelial Growth Factors/genetics , Endothelium, Vascular/drug effects , Endothelium, Vascular/enzymology , Endothelium, Vascular/injuries , Endothelium, Vascular/pathology , Enzyme Activation/drug effects , Enzyme Activation/physiology , Hepatocyte Growth Factor/metabolism , Humans , Intercellular Signaling Peptides and Proteins/biosynthesis , Intercellular Signaling Peptides and Proteins/genetics , Lymphokines/antagonists & inhibitors , Lymphokines/biosynthesis , Lymphokines/genetics , MAP Kinase Signaling System/drug effects , MAP Kinase Signaling System/physiology , Male , Mice , Mice, Inbred BALB C , Mitogen-Activated Protein Kinases/antagonists & inhibitors , Mitogen-Activated Protein Kinases/physiology , Phosphorylation/drug effects , Phthalazines/pharmacology , Protein Serine-Threonine Kinases/antagonists & inhibitors , Protein Serine-Threonine Kinases/physiology , Proto-Oncogene Proteins c-akt , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Receptors, Vascular Endothelial Growth Factor/physiology , Recombinant Proteins/antagonists & inhibitors , Recombinant Proteins/biosynthesis , Recombinant Proteins/genetics , Transfection , Tumor Cells, Cultured , Umbilical Veins/drug effects , Umbilical Veins/enzymology , Umbilical Veins/pathology , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
19.
Expert Opin Investig Drugs ; 11(12): 1715-36, 2002 Dec.
Article in English | MEDLINE | ID: mdl-12457433

ABSTRACT

The inhibition of angiogenesis through vascular endothelial growth factor (VEGF) receptor targeting is a strategy that is relatively tumour selective. The high selectivity achieved with neutralising antibodies, soluble receptors and ribozymes reduces the risk of adverse reactions not related to VEGF inhibition itself. Small-molecule, orally-active protein kinase inhibitors provide an attractive alternative for chronic therapy, although specifically targeting a small subset of protein kinases from the approximately 550 expressed in mammalian cells is a challenge. Current efforts have resulted in promising clinical data for several synthetic VEGF receptor kinase inhibitors, of which PTK787/ZK222584 and ZD6474 are proceeding into large size clinical trials. It seems likely that blockers of the VEGF signalling pathway will be unsuitable for monotherapy, and that their role will be as an adjunct to additional antiangiogenic agents together with directly-acting antitumour agents or radiation therapy. Caution is needed with combinations of anti-VEGF therapies and cytotoxic agents, as coadministration of cytotoxic agents with either the kinase inhibitor SU5416 or the VEGF antibody avastin appears to be associated with bleeding and thrombotic adverse events.


Subject(s)
Angiogenesis Inhibitors/therapeutic use , Antineoplastic Agents/therapeutic use , Endothelial Growth Factors/antagonists & inhibitors , Lymphokines/antagonists & inhibitors , Arthritis, Rheumatoid/etiology , Endothelial Growth Factors/physiology , Genetic Therapy , Intercellular Signaling Peptides and Proteins/physiology , Lymphokines/physiology , Neoplasm Metastasis , Neovascularization, Physiologic , RNA, Catalytic/therapeutic use , Receptors, Vascular Endothelial Growth Factor/antagonists & inhibitors , Receptors, Vascular Endothelial Growth Factor/physiology , Vascular Endothelial Growth Factor A , Vascular Endothelial Growth Factors
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