Benzyl and Naphthalene-Methyl Phosphonic Acid Inhibitors of Autotaxin with Anti-invasive and Anti-metastatic Actions

摘要

Autotaxin (ATX, NPP2) is a member of the nucleotide pyrophosphate phosphodiesterase enzyme family. ATX catalyzes the hydrolytic cleavage of lysophosphatidylcholine (LPC) via a lysophospholipase D activity that leads to the 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. Here we report the synthesis and pharmacological characterization of inhibitors of ATX based on the 4-tetradecanoylaminobenzyl phosphonic acid scaffold that was previously found to lack sufficient stability in cellular systems. The new 4-substituted benzyl phosphonic acid and 6-substituted naphthalen-2-yl-methyl phosphonic acid analogs blocked ATX with Ki values in the low-micromolar-nanomolar range against FS-3, LPC, and nucleotide substrates through a mixed-mode mechanism of inhibition. None of the compounds tested inhibited the activity of related enzymes (NPP6 and NPP7). In addition, the compounds were evaluated as agonists or antagonists of seven LPA receptor subtypes. Analogs >22 and >30b, the two most potent ATX inhibitors, dose-dependently inhibited the invasion of MM1 hepatoma cells across murine mesothelial and human vascular endothelial monolayers in vitro. The average terminal half-life for compound >22 was 10h ± 5.4h and it caused a long-lasting reduction plasma LPA levels. Compounds >22 and >30b significantly reduced lung metastasis of B16-F10 syngeneic mouse melanoma in a post-inoculation treatment paradigm. The described 4-substituted benzyl phosphonic acids and 6-substituted naphthalen-2-yl-methyl phosphonic acids represent new lead compounds that effectively inhibit the ATX-LPA-LPA receptor axis both in vitro and in vivo.