The Design and Synthesis of Autotaxin Inhibitors and Analogs of Lysophosphatidic Acid

Lysophosphatidic acid (LPA) is a naturally occurring bioactive phospholipid. It has a wide array of biological effects like cell proliferation, survival, migration, apoptosis invasion, wound healing and angiogenesis. Autotaxin (ATX) was identified as an autocrine tumor cell motility factor from A2058 melanoma conditioned medium. ATX has lysophospholipase D enzyme activity and is responsible for the cleavage of lysophophatidylcholine (LPC) leading to the generation of LPA. Antagonists of Autotaxin would have a potential therapeutic application in cancer research. Chapter 1 is an introduction of LPA and autotaxin. It provides the background and significance of the research. Chapter 2 explores the synthesis of the stereoisomers of 3‑CCPA and the pharmacological activites of these isomers. Chapter 3 discusses the design and synthesis of benzyl and naphthalene-methyl phosphonic acid inhibitors of autotaxin with anti‑invasive and anti-metastatic actions. Chapter 4 elaborates on the search for new non‑lipid, drug like LPA analogs. Chapter 5 provides an overview of the work detailed in the dissertation; as well as future directions that will help further the scope of these projects

Inflammatory Bowel Disease: Cost-Driving Factors And Impact Of Cost Sharing On Outpatient Resource Utilization

Objectives: (1) To identify the cost-driving factors of health expenditure in inflammatory bowel disease (IBD), (2) to determine the effect of different cost-sharing levels on outpatient visits and (3) to determine the effect of different cost-sharing levels on medication adherence among patients with IBD. Method: This was a retrospective, longitudinal study in which data were collected from 1999 to 2013 using the Medical Expenditure Panel Survey. The study sample included all patients who had IBD, were at least 18 years old, and had insurance. A comprehensive list of demographic factors was assessed to identify cost-driving factors associated with high level of expenditure in IBD. Two logistic regression models were built to examine the association between outpatient cost sharing and number of outpatient visits, and between prescription cost sharing and medication adherence. Statistical significance was evaluated at P \u3c 0.05. Key findings: Significant cost-driving factors included age, body mass index, education, income, quality of life, Charlson Comorbidity Index and region. The study found that low outpatient cost sharing was associated significantly with high level of outpatient visits. However, different levels of prescription cost sharing had no significant relationship with medication adherence. Conclusions: The finding confirms the existence of financial barriers to care in IBD, which may lead to suboptimal outpatient and, thus, the rapid worsening of the diseases. The finding of cost-driving factors allows the identification of high-risk group for high expenditure, which can be used for future cost-saving strategy

Benzyl and naphthalene methylphosphonic acid inhibitors of autotaxin with anti-invasive and anti-metastatic activity

Autotaxin (ATX, NPP2) is a member of the nucleotide pyrophosphate phosphodiesterase enzyme family. ATX catalyzes the hydrolytic cleavage of lysophosphatidylcholine (LPC) by lysophospholipaseD 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 Ki 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 30b, the two most potent ATX inhibitors, inhibit the invasion of MM1 hepatoma cells across murine mesothelial and human vascular endothelial monolayers invitro in a dose-dependent manner. The average terminal half-life for compound 22 is 10±5.4h and it causes a long-lasting decrease in plasma LPA levels. Compounds 22 and 30b 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 invitro and invivo. Inhibiting the ATX-LPA-LPAR axis: New 4-substituted benzylphosphonic acid and 6-substituted naphthalen-2-ylmethylphosphonic acid analogues were synthesized, and the most potent ATX inhibitors, 22 and 30b, show outstanding invivo profiles by diminishing lung metastases of B16-F10 syngeneic mouse melanoma in a post-inoculation treatment model. These two lead compounds effectively inhibit the ATX-LPA-LPAR axis both invitro and invivo. © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

Synthesis and pharmacological evaluation of the stereoisomers of 3-carba cyclic-phosphatidic acid

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 LPA5 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 LPA5 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. © 2010 Elsevier Ltd. All rights reserved

Virtual screening for LPA2-specific agonists identifies a nonlipid compound with antiapoptotic actions

Lysophosphatidic acid (LPA) is a highly potent endogenous lipid mediator that protects and rescues cells from programmed cell death. Earlier work identified the LPA2 G protein-coupled receptor subtype as an important molecular target of LPA mediating antiapoptotic signaling. Here we describe the results of a virtual screen using single-reference similarity searching that yielded compounds 2-((9-oxo-9H-fluoren-2-yl)carbamoyl)benzoic acid (NSC12404), 2-((3-(1,3-dioxo-1H-benzo-[de]isoquinolin-2(3H)-yl)propyl)thio) benzoic acid (GRI977143), 4,5-dichloro-2-((9-oxo-9H-fluoren-2-yl)carbamoyl) benzoic acid (H2L55-47924), and 2-((9,10-dioxo-9,10-dihydroanthracen-2-yl) carbamoyl)benzoic acid (H2L5828102), novel nonlipid and drug-like compounds that are specific for the LPA2 receptor subtype. We characterized the antiapoptotic action of one of these compounds, GRI977143, which was effective in reducing activation of caspases 3, 7, 8, and 9 and inhibited poly(ADP-ribose)polymerase 1 cleavage and DNA fragmentation in different extrinsic and intrinsic models of apoptosis in vitro. Furthermore, GRI977143 promoted carcinoma cell invasion of human umbilical vein endothelial cell monolayers and fibroblast proliferation. The antiapoptotic cellular signaling responses were present selectively in mouse embryonic fibroblast cells derived from LPA1&2double-knockout mice reconstituted with the LPA 2 receptor and were absent in vector-transduced control cells. GRI977143 was an effective stimulator of extracellular signal-regulated kinase 1/2 activation and promoted the assembly of a macromolecular signaling complex consisting of LPA2, Na+-H+ exchange regulatory factor 2, and thyroid receptor interacting protein 6, which has been shown previously to be a required step in LPA-induced antiapoptotic signaling. The present findings indicate that nonlipid LPA2-specific agonists represent an excellent starting point for development of lead compounds with potential therapeutic utility for preventing the programmed cell death involved in many types of degenerative and inflammatory diseases. Copyright © 2012 The American Society for Pharmacology and Experimental Therapeutics