RESUMEN
In the quest to discover a potent and selective class of direct agonists to the sphingosine-1-phosphate receptor, we explored the carboxylate functional group as a replacement to previously reported lead phosphates. This has led to the discovery of potent and selective direct agonists with moderate to substantial in vivo lymphopenia. The previously reported selectivity enhancing moiety (SEM) and selectivity enhancing orientation (SEO) in the phenylamide and phenylimidazole scaffolds were crucial to obtaining selectivity for S1P receptor subtype 1 over 3.
Asunto(s)
Aminoácidos/química , Aminoácidos/farmacología , Linfopenia , Receptores de Lisoesfingolípidos/agonistas , Receptores de Lisoesfingolípidos/química , Administración Oral , Aminoácidos/administración & dosificación , Animales , Concentración 50 Inhibidora , Ratones , Estructura Molecular , Unión Proteica/efectos de los fármacos , Receptores de Lisoesfingolípidos/metabolismoRESUMEN
To develop effective oral treatment for multiple sclerosis (MS), we discovered a series of alkyl-substituted biaryl amino alcohols as selective S1P1 modulators. One exemplar is (S)-2-amino-2-(5-(4-(octyloxy)-3-(trifluoromethyl)phenyl)-1,3,4-thiadiazol-2-yl)propan-1-ol (10, GSK1842799). Upon phosphorylation, the compound (10-P) showed subnanomole S1P1 agonist activity with >1000× selectivity over S1P3. The alcohol 10 demonstrated good oral bioavailability and rapid in vivo conversion to 10-P. Dosed orally at 0.1 mg/kg, 10 significantly reduced blood lymphocyte counts 6 h postdose, and at 3 mg/kg, 10 achieved efficacy equivalent to FTY720 in the mouse EAE model of MS. Further pharmacokinetic/pharmacodynamic (PK/PD) study with cynomolgus monkeys indicated that, after oral dosing of 10 at 3.8 mg/kg, the active phosphate reached plasma levels that are comparable to FTY-720 phosphate (FTY-P) revealed in human clinical pharmacokinetics studies. On the basis of the favorable in vitro ADME and in vivo PK/PD properties as well as broad toxicology evaluations, compound 10 (GSK1842799) was selected as a candidate for further clinical development.
RESUMEN
In pursuit of a potent and highly selective sphingosine-1-phosphate receptor agonists with an improved in vivo conversion of the precursor to the active phospho-drug, we have utilized previously reported phenylamide and phenylimidazole scaffolds to identify a selectivity enhancing moiety (SEM) and selectivity enhancing orientation (SEO) within both pharmacophores. SEM and SEO have allowed for over 100 to 500-fold improvement in selectivity for S1P receptor subtype 1 over subtype 3. Utility of SEM and SEO and further SAR study allowed for discovery of a potent and selective preclinical candidate PPI-4955 (21b) with an excellent in vivo potency and dose responsiveness and markedly improved overall in vivo pharmacodynamic properties upon oral administration.
Asunto(s)
Amino Alcoholes/farmacología , Receptores de Lisoesfingolípidos/agonistas , Administración Oral , Amino Alcoholes/administración & dosificación , Animales , Ratones , Relación Estructura-ActividadRESUMEN
In pursuit of potent and selective sphingosine-1-phosphate receptor agonists, we have utilized previously reported phenylamide and phenylimidazole scaffolds to explore extensive side-chain modifications to generate new molecular entities. A number of designed molecules demonstrate good selectivity and excellent in vitro and in vivo potency in both mouse and rat models. Oral administration of the lead molecule 11c (PPI-4667) demonstrated potent and dose-responsive lymphopenia.
Asunto(s)
Amidas/síntesis química , Imidazoles/síntesis química , Receptores de Lisoesfingolípidos/agonistas , Amidas/farmacología , Animales , Relación Dosis-Respuesta a Droga , Evaluación Preclínica de Medicamentos/métodos , Clorhidrato de Fingolimod , Imidazoles/farmacología , Ratones , Glicoles de Propileno/química , Glicoles de Propileno/farmacología , Subunidades de Proteína/agonistas , Subunidades de Proteína/fisiología , Receptores de Lisoesfingolípidos/fisiología , Esfingosina/análogos & derivados , Esfingosina/química , Esfingosina/farmacologíaRESUMEN
In the design of potent and selective sphingosine-1-phosphate receptor agonists, we were able to identify two series of molecules based on phenylamide and phenylimidazole analogs of FTY-720. Several designed molecules in these scaffolds have demonstrated selectivity for S1P receptor subtype 1 versus 3 and excellent in vivo activity in mouse. Two molecules PPI-4621 (4b) and PPI-4691 (10a), demonstrated dose responsive lymphopenia, when administered orally.
Asunto(s)
Amidas/síntesis química , Amidas/farmacología , Imidazoles/síntesis química , Imidazoles/farmacología , Receptores de Lisoesfingolípidos/agonistas , Amidas/química , Animales , Relación Dosis-Respuesta a Droga , Humanos , Imidazoles/química , Ratones , Relación Estructura-ActividadRESUMEN
OBJECTIVE: To determine the disease-modifying activity and mechanism of action of the orally available methionine aminopeptidase type 2 inhibitor, [(1R)-1-carbamoyl-2-methyl-propyl]-carbamic acid-(3R,4S,5S,6R)-5-methoxy-4-[(2R,3R)-2-methyl-3-(3-methyl-but-2-enyl)-oxiranyl]-1-oxa-spiro [2.5] oct-6-yl ester (PPI-2458), in a rat model of peptidoglycan-polysaccharide (PG-PS)-induced arthritis. METHODS: Arthritis was induced in rats by administration of PG-PS, causing tarsal joint swelling and histopathologic changes characteristic of rheumatoid arthritis (RA). PPI-2458, a potent irreversible methionine aminopeptidase type 2 inhibitor, was administered orally every other day at 1, 5, or 10 mg/kg. RESULTS: In an in vitro osteoclastogenesis model, PPI-2458 potently inhibited osteoclast differentiation and bone resorption. In the rat PG-PS arthritis model, PPI-2458 afforded significant protection against established disease after therapeutic dosing. This in vivo activity of PPI-2458 was linked to the inhibition of methionine aminopeptidase type 2. Histopathologic assessment of affected joints showed improvement in processes of inflammation, bone resorption, and cartilage erosion, associated with significant improvement in all clinical indices. The protective effects of PPI-2458 against bone destruction in vivo, including the structural preservation of affected hind joints, correlated with improvements in bone histomorphometric markers, as determined by microfocal computed tomography and a significant decrease in systemic C-telopeptide of type I collagen, suggesting decreased osteoclast activity in vivo. Moreover, PPI-2458 prevented cartilage erosion as shown by a significant decrease in systemic cartilage oligomeric matrix protein. CONCLUSION: The findings of this study suggest that PPI-2458 exerts disease-modifying activity in experimental arthritis through its direct inhibition of several pathophysiologic processes of this disease. These results provide a rationale for assessing the potential of PPI-2458 as a novel RA therapy.
Asunto(s)
Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/patología , Inhibidores Enzimáticos/uso terapéutico , Compuestos Epoxi/uso terapéutico , Valina/análogos & derivados , Aminopeptidasas/antagonistas & inhibidores , Animales , Artritis Reumatoide/inducido químicamente , Resorción Ósea/patología , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Modelos Animales de Enfermedad , Inhibidores Enzimáticos/farmacología , Compuestos Epoxi/farmacología , Femenino , Glicoproteínas/antagonistas & inhibidores , Humanos , Articulaciones/patología , Articulaciones/fisiopatología , Osteoclastos/efectos de los fármacos , Osteoclastos/patología , Peptidoglicano , Polisacáridos , Ratas , Ratas Endogámicas Lew , Índice de Severidad de la Enfermedad , Valina/farmacología , Valina/uso terapéuticoRESUMEN
Over the past few decades, melanoma has shown the fastest growing incidence rate of all cancers. This malignancy is clinically defined by its potential to rapidly metastasize, and advanced metastatic melanomas are highly resistant to existing therapeutic regimens. Here, we report that PPI-2458, a novel, orally active agent of the fumagillin class of irreversible methionine aminopeptidase-2 (MetAP-2) inhibitors, potently inhibited the proliferation of B16F10 melanoma cells in vitro, with a growth inhibitory concentration 50% (GI50) of 0.2 nM. B16F10 growth inhibition was correlated with the inhibition of MetAP-2 enzyme, in a dose-dependent fashion, as determined by a pharmacodynamic assay, which measures the amount of uninhibited MetAP-2 following PPI-2458 treatment. Prolonged exposure of B16F10 cells to PPI-2458 at concentrations of up to 1 microM, 5,000-fold above the GI50, did not alter their sensitivity to PPI-2458 growth inhibition and no drug resistance was observed. Moreover, prolonged exposure to this agent induced melanogenesis, concomitant with the elevated expression of the melanocyte-specific enzymes tyrosinase and tyrosinase-related proteins (TRP) 1 and 2, a morphological feature associated with differentiated melanocytes. PPI-2458, when administered orally (p.o.), significantly inhibited B16F10 tumor growth in mice in a dose-dependent fashion, with a maximum inhibition of 62% at 100 mg/kg. This growth inhibition was directly correlated to the amount of irreversibly inhibited MetAP-2 (80% at 100 mg/kg PPI-2458) in tumor tissue. These data demonstrate that PPI-2458 has potent antiproliferative activity against B16F10 cells in vitro and in vivo, and that both activities are directly correlated with levels of MetAP-2 enzyme inhibition. This antiproliferative activity, coupled with additional observations from studies in vitro (absence of detectable resistance to PPI-2458 and induction of morphological features consistent with differentiated melanocytes), provides a rationale for assessing the therapeutic potential of PPI-2458 in the treatment of melanoma.