LFA‐9, a Selective Inhibitor of Microsomal Prostaglandin Synthase‐1 and 5‐Lipoxygenase: Prevention of Inflammatory and Oncologic Diseases

Abstract

Cyclooxygenase‐1 (COX‐1), COX‐2 and 5‐lipoxygenase (5‐LOX) as targets for inflammatory diseases and many agents were developed and extensively used in the clinic. Chronic use of drugs that target COX‐1/COX‐2 are associated with unwanted side effects including GI toxicity and cardiovascular risk. Hence, the main aim of this work is to develop mechanistic based safer agents that would target microsomal prostaglandin synthase‐1 (mPGES‐1) (a downstream enzyme of COX‐2) and 5‐LOX, while sparing COX‐1&‐2 activity. LFA‐9 was designed using structure‐based drug discovery and synthesized from licofelone by adding 2‐aminoethanoic acid (Glycine) at its carboxylic end that led to targeting mPGES‐1 and 5‐LOX but not COX‐1&2. In silico, in vitro and ex vivo studies on LFA‐9 were performed using human/mouse/rat mPGES‐1 and 5‐LOX to facilitate pre‐clinical experimentation and clinical translation. In the molecular docking studies, LFA‐9 showed strong binding affinity against 5‐LOX (binding energies range between −199.85 & −215.3 Kcal/mol) and mPGES‐1 (binding energies range between −238.27 & −257.76 Kcal/mol), but not with COX‐1&2. In cell free system studies, LFA‐9 substantially inhibited mPGES‐1 (range of IC50 between 0.52 – 1.40 μM) and 5‐LOX (range of IC50 between 0.89 – 2.75 μM) but not COX‐1&2 (IC50>1mM) when assayed using fluorometric and colorimetric methods. Moreover, LFA‐9 substantially inhibited PGE2 (IC50 range between 0.47 – 0.78 μM) and LTB4 (IC50 range between 0.56 – 1.24 μM) production and spared PGI2 (IC50>1 mM) and TXB2 (IC50>1 mM) production in LPS‐stimulated human/mouse/rat macrophages and whole blood as the cell‐based system using ELISA technique. Further, circular dichroism and isothermal calorimetric based studies demonstrated that LFA‐9 strongly binds and induces changes in secondary structure of human mPGES‐1 and 5‐LOX enzymes, thereby inhibits their activities. In addition, LFA‐9 (cLogP = 4.34) obeys Lipinsky’s rule of 5 for druglikeness and shows better water solubility unlike licofelone (cLogP = 6.15). Furthermore, LFA9 prevented tumor stemness of APC mutant colonic epithelial cells from PIRC rats in vitro and inhibited exogenous PGE2 in tumor like microenvironment. Therefore, LFA9 is a novel mPGES‐1 and 5‐LOX inhibitor and safer drug candidate for inflammatory and oncologic diseases.Support or Funding InformationAuthors acknowledged NIH/NCI R01CA 213987 and NIH/NCI HHSN261201500024I for funding support.Chemical structures of Licofelone and LFA9Figure 1