ABSTRACT
Sphingosine-1-phosphate receptor 1 (S1P1) mediated regulation of lymphocyte egress from lymphoid organs is recognized as the mechanism of FTY720 (Fingolimod, Gilenya) efficacy in relapsing-remitting forms of multiple sclerosis (RRMS). In this study we describe a novel S1P1 agonist AKP-11, next generation of S1P1 agonist, with immunomodulatory activities in cell culture model and for therapeutic efficacy against an animal model of MS, i.e. experimental autoimmune encephalomyelitis (EAE) but without the adverse effects observed with FTY720. Like FTY720, AKP-11 bound to S1P1 is internalized and activates intracellular AKT and ERKs cellular signaling pathways. In contrast to FTY720, AKP-11 mediated S1P1 downregulation is independent of sphingosine kinase activity indicating it to be a direct agonist of S1P1. The S1P1 loss and inhibition of lymphocyte egress by FTY720 leads to lymphopenia. In comparison with FTY720, oral administration of AKP-11 caused milder and reversible lymphopenia while providing a similar degree of therapeutic efficacy in the EAE animal model. Consistent with the observed reversible lymphopenia with AKP-11, the S1P1 recycled back to cell membrane in AKP-11 treated cells following its withdrawal, but not with withdrawal of FTY720. Accordingly, a smaller degree of ubiquitination and proteolysis of S1P1 was observed in AKP-11 treated cells as compared to FTY720. Consistent with previous observations, FTY720 treatment is associated with adverse effects of bradycardia and lung vascular leaks in rodents, whereas AKP-11 treatment had undetectable effects on bradycardia and reduced lung vascular leaks as compared to FTY720. Taken together, the data documents that AKP-11 treatment cause milder and reversible lymphopenia with milder adverse effects while maintaining therapeutic efficacy similar to that observed with FTY720, thus indicating therapeutic potential of AKP-11 for treatment of MS and related autoimmune disorders.
Subject(s)
Encephalomyelitis, Autoimmune, Experimental/immunology , Encephalomyelitis, Autoimmune, Experimental/metabolism , Multiple Sclerosis/immunology , Multiple Sclerosis/metabolism , Receptors, Lysosphingolipid/agonists , Animals , CHO Cells , Capillary Permeability/drug effects , Cell Membrane/metabolism , Cricetulus , Cytokines/metabolism , Disease Models, Animal , Encephalomyelitis, Autoimmune, Experimental/drug therapy , Extracellular Signal-Regulated MAP Kinases/metabolism , Female , Fingolimod Hydrochloride/administration & dosage , Fingolimod Hydrochloride/pharmacology , Heart Rate/drug effects , Lymphocyte Count , Multiple Sclerosis/drug therapy , Proteolysis , Proto-Oncogene Proteins c-akt/metabolism , Rats , T-Lymphocyte Subsets/immunology , T-Lymphocyte Subsets/metabolismABSTRACT
A structure-activity relationship (SAR) guided design of novel tubulin polymerization inhibitors has resulted in a series of benzo[b]furans with exceptional potency toward cancer cells and activated endothelial cells. The potency of early lead compounds has been substantially improved through the synergistic effect of introducing a conformational bias and additional hydrogen bond donor to the pharmacophore. Screening of a focused library of potent tubulin polymerization inhibitors for selectivity against cancer cells and activated endothelial cells over quiescent endothelial cells has afforded 7-hydroxy-6-methoxy-2-methyl-3-(3,4,5-trimethoxybenzoyl)benzo[b]furan (BNC105, 8) as a potent and selective antiproliferative. Because of poor solubility, 8 is administered as its disodium phosphate ester prodrug 9 (BNC105P), which is rapidly cleaved in vivo to return the active 8. 9 exhibits both superior vascular disrupting and tumor growth inhibitory properties compared with the benchmark agent combretastatin A-4 disodium phosphate 5 (CA4P).
Subject(s)
Anisoles/pharmacology , Aorta/drug effects , Benzofurans/pharmacology , Cell Proliferation/drug effects , Endothelium, Vascular/drug effects , Neovascularization, Physiologic/drug effects , Tubulin Modulators/pharmacology , Anisoles/chemical synthesis , Anisoles/chemistry , Aorta/cytology , Benzofurans/chemical synthesis , Benzofurans/chemistry , Cells, Cultured , Endothelium, Vascular/cytology , Humans , Structure-Activity Relationship , Tubulin Modulators/chemical synthesis , Tubulin Modulators/chemistryABSTRACT
A convenient method for the synthesis of 2-bromo-3-aroyl-benzo[b]furans from readily accessible precursors has been developed. The 2-bromo group has been employed as a versatile synthetic handle in both palladium-mediated couplings and direct nucleophilic substitutions to give access to a wide range of 2-substituted-3-aroyl-benzo[b]furans.
