Tricyclic 4,4-dimethyl-3,4-dihydrochromeno[3,4- d ]imidazole derivatives as microsomal prostaglandin E 2 synthase-1 (mPGES-1) inhibitors: SAR and in vivo efficacy in hyperalgesia pain model

Selective COX-2 inhibitors as anticancer agents: a patent review (2018-2023)

INTRODUCTION

COX-2 is a crucial enzyme in the manufacture of prostaglandins. The enzyme's metabolites might have an important function as regulators of the inflammatory response and other medical conditions such as cancer. Selective COX-2 inhibitors are believed to enhance or reverse the response of cancer chemotherapeutics.

AREAS COVERED

This study addresses the chemical structures as well as the antitumor activity of new COX-2 inhibitors produced in the recent five years, aiming to provide an insight into the mechanism of COX-2 induced PGE2 powerful signal in cancer development.

EXPERT OPINION

The significance of selective COX-2 inhibitors as an efficient superfamily of compounds with anti-inflammatory, anti-Alzheimer's, anti-Parkinson's disease, and anticancer properties has piqued the passion of academics in the field of drug development. Long-term usage of selective COX-2 inhibitors, such as celecoxib has been proven in clinical trials to lower the incidence of several human malignancies. Furthermore, celecoxib has the potential to greatly increase the effectiveness of chemotherapy. Our extensive understanding of selective COX-2 inhibitor SAR may aid in the development of safer and more effective selective COX-2 inhibitors as cancer chemopreventive agents. This review focuses on the different structural classes of selective COX-2 inhibitors, with a particular emphasis on their SAR.

A review on mPGES-1 inhibitors: From preclinical studies to clinical applications

Prostaglandin E₂ (PGE₂) is a lipid mediator of inflammation and cancer progression. It is mainly formed via metabolism of arachidonic acid by cyclooxygenases (COX) and the terminal enzyme microsomal prostaglandin E synthase-1 (mPGES-1). Widely used non-steroidal anti-inflammatory drugs (NSAIDs) inhibit COX activity, resulting in decreased PGE₂ production and symptomatic relief. However, NSAIDs block the production of many other lipid mediators that have important physiological and resolving actions, and these drugs cause gastrointestinal bleeding and/or increase the risk for severe cardiovascular events. Selective inhibition of downstream mPGES-1 for reduction in only PGE₂ biosynthesis is suggested as a safer therapeutic strategy. This review covers the recent advances in characterization of new mPGES-1 inhibitors in preclinical models and their future clinical applications.

Alleviating CYP and hERG liabilities by structure optimization of dihydrofuran-fused tricyclic benzo[d]imidazole series - Potent, selective and orally efficacious microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors: Part-2

In an effort to identify CYP and hERG clean mPGES-1 inhibitors from the dihydrofuran-fused tricyclic benzo[d]imidazole series lead 7, an extensive structure-activity relationship (SAR) studies were performed. Optimization of A, D and E-rings in 7 afforded many potent compounds with human whole blood potency in the range of 160-950 nM. Selected inhibitors 21d, 21j, 21m, 21n, 21p and 22b provided selectivity against COX-enzymes and mPGES-1 isoforms (mPGES-2 and cPGES) along with sufficient selectivity against prostanoid synthases. Most of the tested analogs demonstrated required metabolic stability in liver microsomes, low hERG and CYP liability. Oral pharmacokinetics and bioavailability of lead compounds 21j, 21m and 21p are discussed in multiple species like rat, guinea pig, dog, and cynomolgus monkey. Besides, these compounds revealed low to moderate activity against human pregnane X receptor (hPXR). The selected lead 21j further demonstrated in vivo efficacy in acute hyperalgesia (ED₅₀: 39.6 mg/kg) and MIA-induced osteoarthritic pain models (ED₅₀: 106 mg/kg).

Discovery of furan and dihydrofuran-fused tricyclic benzo[d]imidazole derivatives as potent and orally efficacious microsomal prostaglandin E synthase-1 (mPGES-1) inhibitors: Part-1

This letter describes the synthesis and biological evaluation of furan and dihydrofuran-fused tricyclic benzo[d]imidazole derivatives as novel mPGES-1 inhibitors, capable of inhibiting an increased PGE₂ production in the disease state. Structure-activity optimization afforded many potent mPGES-1 inhibitors having <50 nM potencies in the A549 cellular assay and adequate metabolic stability in liver microsomes. Lead compounds 8l and 8m demonstrated reasonable in vitro pharmacology and pharmacokinetic properties over other compounds. In particular, 8m revealed satisfactory oral pharmacokinetics and bioavailability in multiple species like rat, guinea pig, dog and cynomolgus monkey. In addition, the representative compound 8m showed in vivo efficacy by inhibiting LPS-induced thermal hyperalgesia with an ED₅₀ of 14.3 mg/kg in guinea pig.