ABSTRACT
Autotaxin (ATX, NPP2) is a member of the nucleotide pyrophosphate phosphodiesterase enzyme family. ATX catalyzes the hydrolytic cleavage of lysophosphatidylcholine (LPC) by lysophospholipaseâ D activity, which leads to generation of the growth-factor-like lipid mediator lysophosphatidic acid (LPA). ATX is highly upregulated in metastatic and chemotherapy-resistant carcinomas and represents a potential target to mediate cancer invasion and metastasis. Herein we report the synthesis and pharmacological characterization of ATX inhibitors based on the 4-tetradecanoylaminobenzylphosphonic acid scaffold, which was previously found to lack sufficient stability in cellular systems. The new 4-substituted benzylphosphonic acid and 6-substituted naphthalen-2-ylmethylphosphonic acid analogues block ATX activity with K(i) values in the low micromolar to nanomolar range against FS3, LPC, and nucleotide substrates through a mixed-mode inhibition mechanism. None of the compounds tested inhibit the activity of related enzymes (NPP6 and NPP7). In addition, the compounds were evaluated as agonists or antagonists of seven LPA receptor (LPAR) subtypes. Analogues 22 and 30 b, the two most potent ATX inhibitors, inhibit the invasion of MM1 hepatoma cells across murine mesothelial and human vascular endothelial monolayers inâ vitro in a dose-dependent manner. The average terminal half-life for compound 22 is 10±5.4â h and it causes a long-lasting decrease in plasma LPA levels. Compounds 22 and 30 b significantly decrease lung metastasis of B16-F10 syngeneic mouse melanoma in a post-inoculation treatment paradigm. The 4-substituted benzylphosphonic acids and 6-substituted naphthalen-2-ylmethylphosphonic acids described herein represent new lead compounds that effectively inhibit the ATX-LPA-LPAR axis both inâ vitro and inâ vivo.
Subject(s)
Antineoplastic Agents/chemistry , Enzyme Inhibitors/chemistry , Multienzyme Complexes/antagonists & inhibitors , Naphthalenes/chemistry , Organophosphonates/chemistry , Organophosphorus Compounds/chemistry , Phosphodiesterase I/antagonists & inhibitors , Pyrophosphatases/antagonists & inhibitors , Animals , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Cell Movement/drug effects , Disease Models, Animal , Enzyme Inhibitors/chemical synthesis , Enzyme Inhibitors/therapeutic use , Humans , Liver Neoplasms/drug therapy , Melanoma, Experimental/drug therapy , Mice , Multienzyme Complexes/metabolism , Naphthalenes/chemical synthesis , Naphthalenes/therapeutic use , Neoplasm Invasiveness , Neoplasm Metastasis , Organophosphonates/chemical synthesis , Organophosphonates/therapeutic use , Organophosphorus Compounds/chemical synthesis , Organophosphorus Compounds/therapeutic use , Phosphodiesterase I/metabolism , Phosphoric Diester Hydrolases , Pyrophosphatases/metabolismABSTRACT
Cyclic phosphatidic acid (CPA) is a naturally occurring analog of lysophosphatidic acid (LPA) in which the sn-2 hydroxy group forms a five-membered ring with the sn-3 phosphate. Here, we describe the synthesis of R-3-CCPA and S-3-CCPA along with their pharmacological properties as inhibitors of lysophospholipase D/autotaxin, agonists of the LPA(5) GPCR, and blockers of lung metastasis of B16-F10 melanoma cells in a C57BL/6 mouse model. S-3CCPA was significantly more efficacious in the activation of LPA(5) compared to the R-stereoisomer. In contrast, no stereoselective differences were found between the two isomers toward the inhibition of autotaxin or lung metastasis of B16-F10 melanoma cells in vivo. These results extend the potential utility of these compounds as potential lead compounds warranting evaluation as cancer therapeutics.
