Structure-Based Design of Microsomal Prostaglandin E 2 Synthase-1 (mPGES-1) Inhibitors using a Virtual Fragment Growing Optimization Scheme Gianluigi Lauro + , [a] Paolo Tortorella + , [b] Alessia Bertamino, [a] Carmine Ostacolo, [c] Andreas Koeberle, [d] Katrin Fischer, [d] Ines Bruno, [a] Stefania Terracciano, [a] Isabel Maria Gomez-Monterrey, [c] Marilena Tauro, [b] Fulvio Loiodice, [b] Ettore Novellino, [c] Raffaele Riccio, [a] Oliver Werz, [d] Pietro Campiglia,* [a] and Giuseppe Bifulco* [a] Introduction The causative relationship between inflammation and tumor progression is nowadays clearly evident. [1] Patients affected by long-term chronic inflammatory diseases are, for example, prone to the development of a neoplasm at the target organ, [2] whereas individuals taking nonsteroidal anti-inflamma- tory drugs (NSAIDs) are protected against the onset of tumori- genesis and progression of metastasis. [3] Moreover, the local pro-inflammatory microenvironment in tumor cells character- ized by high levels of pro-inflammatory cytokines and lipid me- diators, has been implicated in increased tumor growth and in- vasiveness. [4] This is why several NSAIDs have been studied and proposed for the prevention and treatment of different neoplastic diseases. [5] The clinical use of NSAIDs in cancer treat- ment is unfortunately limited by their interference with cyclo- oxygenase (COX) enzymes leading to severe side effects such as nausea, dyspepsia, gastritis, abdominal pain, peptic ulcer, gastrointestinal bleeding, and/or perforation of gastroduodenal ulcers, [6] mainly associated with the inhibition of the constitu- tive isoform COX-1. On the other hand, the use of selective in- hibitors of the inducible isoform COX-2, despite decreased gas- trointestinal side effects and clear chemopreventive/chemo- therapeutic effects, [7] has been associated with increased thrombotic events in humans in long-term therapies. [8] The de- velopment of safer alternatives to COX inhibitors is therefore desirable. Prostaglandin E 2 synthases (PGES, namely mPGES-1, mPGES- 2 and cPGES) are terminal enzymes involved in the biosynthe- sis of the inflammatory lipid mediator PGE 2 . [9] While mPGES-2 and cPGES represent the constitutive forms, the inducible membrane-bound isoform mPGES-1 has become a key drug target in PGE 2 -related acute and chronic disorders, [10] such as rheumatoid arthritis, [11] osteoarthritis, [12] pain, [13] fever, [14] inflam- mation, [15] and cancer. [16] Starting from these considerations, mPGES-1 inhibition is then crucial for the development of new anti-inflammatory/anticancer agents. In the last years, mPGES-1 inhibitors emerged as new valua- ble drugs that block the conversion of PGH 2 , enzymatically produced by COX enzymes, to PGE 2 . Interestingly, mPGES-1 in- hibitors have been proposed to have lower risks of undesired A small library of 2,3-dihydroxybenzamide- and N-(2,3-dihy- droxyphenyl)-4-sulfonamide-based microsomal prostaglan- din E 2 synthase-1 (mPGES-1) inhibitors was identified following a step-by-step optimization of small aromatic fragments select- ed to interact in focused regions in the active site of mPGES-1. During the virtual optimization process, the 2,3-dihydroxyben- zamide moiety was first selected as a backbone of the pro- posed new chemical entities; the identified compounds were then synthesized and biologically evaluated, identifying deriva- tives with very promising inhibitory activities in the micromolar range. Subsequent structure-guided replacement of the 2,3-di- hydroxybenzamide by the N-(2,3-dihydroxyphenyl)sulfonamide moiety led to the identification of N-(2,3-dihydroxyphenyl)-4- biphenylsulfonamide (6), the most potent small molecule of the series (IC 50 = 0.53  0.04 mm). The simple synthetic proce- dure and the possibility of enhancing the potency of this class of inhibitors through additional structural modifications pave the way for further development of new molecules with mPGES-1-inhibitory activity, with potential application as anti- inflammatory and anticancer agents. [a] Dr. G. Lauro, + Dr. A. Bertamino, Prof. I. Bruno, Dr. S. Terracciano, Prof. R. Riccio, Prof. P. Campiglia, Prof. G. Bifulco Department of Pharmacy, Università di Salerno Via Giovanni Paolo II 132, 84084 Fisciano, SA (Italy) E-mail : bifulco@unisa.it pcampiglia@unisa.it [b] Prof. P. Tortorella, + Dr. M. Tauro, Prof. F. Loiodice Department of Pharmacy, Università degli Studi di Bari “Aldo Moro” Via Orabona 4, 70126 Bari (Italy) [c] Dr. C. Ostacolo, Dr. I. M. Gomez-Monterrey, Prof. E. Novellino Department of Pharmacy, Università degli Studi di Napoli “Federico II” Via Montesano 49, 80131 Napoli (Italy) [d] Dr. A. Koeberle, K. Fischer, Prof. O. Werz Department of Pharmaceutical/Medicinal Chemistry Institute of Pharmacy, University of Jena Philosophenweg 14, 07743 Jena (Germany) [ + ] These authors contributed equally to this work. Supporting information for this article can be found under http:// dx.doi.org/10.1002/cmdc.201500598. ChemMedChem 2016, 11, 612 – 619 # 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 612 Full Papers DOI: 10.1002/cmdc.201500598