Castrate-resistant prostate cancer (CRPC) is a fatal, metastatic form of prostate cancer. CRPC is characterized by reactivation of the androgen axis due to changes in androgen receptor signaling and/or adaptive intratumoral androgen biosynthesis. AKR1C3 is upregulated in CRPC where it catalyzes the formation of potent androgens. This makes AKR1C3 a target for the treatment of CRPC. AKR1C3 inhibitors should not inhibit AKR1C1/AKR1C2, which inactivate 5α-dihydrotestosterone. Indomethacin, used to inhibit cyclooxygenase, also inhibits AKR1C3 and displays selectivity over AKR1C1/AKR1C2. Parallel synthetic strategies were used to generate libraries of indomethacin analogues, which exhibit reduced cyclooxygenase inhibitory activity but retain AKR1C3 inhibitory potency and selectivity. The lead compounds inhibited AKR1C3 with nanomolar potency, displayed >100-fold selectivity over AKR1C1/AKR1C2, and blocked testosterone formation in LNCaP-AKR1C3 cells. The AKR1C3·NADP+·2′-des-methyl-indomethacin crystal structure was determined, and it revealed a unique inhibitor binding mode. The compounds reported are promising agents for the development of therapeutics for CRPC.

The synthesis, biological testing, and SAR of novel 2,4,5- and 1,2,4,5-substituted 2-thioimidazoles are described. Amino, oxy, or thioxy substituents at the 2-position of the pyridinyl moiety were evaluated for their contributions to inhibitor potency and selectivity against p38 mitogen activated protein kinase (p38 MAPK) as well as for the ability to minimize cytochrome P450 (CYP450) inhibition. Incorporation of polar substituted (cyclo)aliphatic amino substituents (e.g., tetrahydropyranylamino), which positively interacted with the surface-exposed front region (hydrophobic region II) of the enzyme led to the identification of extremely potent p38 MAPK inhibitors with p38 IC 50 values in the low nanomolar range. Approximately 90 pyridinylimidazole-based compounds with a range of potencies against p38alpha MAP kinase were further investigated for their ability to inhibit the release of tumor necrosis factor-alpha (TNFalpha) and/or interleukin-1beta (IL-1beta) from human whole blood. Some of the most promising drug candidates underwent selectivity profiling against a panel of 17 different kinases besides p38alpha and/or were tested for their interaction potential toward a number of metabolically relevant CYP450 isozymes.

Prostaglandins (PGs) are powerful lipid mediators in many physiological and pathophysiological responses. They are produced by oxidation of arachidonic acid (AA) by cyclooxygenases (COX-1 and COX-2) followed by metabolism of endoperoxide intermediates by terminal PG synthases. PG biosynthesis is inhibited by nonsteroidal anti-inflammatory drugs (NSAIDs). Specific inhibition of COX-2 has been extensively investigated, but relatively few COX-1-selective inhibitors have been described. Recent reports of a possible contribution of COX-1 in analgesia, neuroinflammation, or carcinogenesis suggest that COX-1 is a potential therapeutic target. We designed, synthesized, and evaluated a series of (E)-2′-des-methyl-sulindac sulfide (E-DMSS) analogues for inhibition of COX-1. Several potent and selective inhibitors were discovered, and the most promising compounds were active against COX-1 in intact ovarian carcinoma cells (OVCAR-3). The compounds inhibited tumor cell proliferation but only at concentrations >100-fold higher than the concentrations that inhibit COX-1 activity. E-DMSS analogues may be useful probes of COX-1 biology in vivo and promising leads for COX-1-targeted therapeutic agents.

We synthesized and evaluated inhibitors for the microsomal prostaglandin E2 synthase-1 (mPGES-1), based on the arylpyrrolizine scaffold. In a cell free mPGES-1 assay several "sulfonimides" exceeded our lead ML3000 (3) in potency. The most promising compound, the tolylsulfonimide 11f, revealed an IC50 of 2.1 microM and is equipotent to the literature reference molecule MK886 (1). Selected compounds also potently reduced 5-LOX product formation in intact cells. Inhibition of isolated COX was occasionally remarkably cut down.

Imidazoles represent important bioactive scaffolds in medicinal chemistry. More than 2,500 structures are listed in drug discovery databases and over 3,000 patents have been claimed for imidazole-based structures. Recent imidazole pharmacophores have targeted various MAP kinases. p38 Mitogen-activated protein (MAP) kinase plays a central role in the signaling network responsible for the upregulation of proinflammatory cytokines like IL-1b and TNFa and offers, therefore, a valid target for small molecule anti-inflammatory drugs. 2-Sulfanylimidazole derivatives offer some advantages over prototype inhibitors (SB203580), e.g. lower cytochrom P450 interactions and better kinetic properties. We report here three novel regioselective and, at the same time, highly flexible synthetic approaches towards 1,4,5-trisubstituted 2-sulfanylimidazoles starting from different ethanone regioisomers allowing maximum variability of all substituents introduced. As a result, a variety of selective and highly potent p38 MAPK inhibitors were prepared and selected for further preclinical development. Synthesis of structurally diverse inhibitor candidates, p38 inhibition data, and selectivity profiling of some selected compounds are specified. Furthermore, the benefits of the useful, brief synthetic sequences are outlined and contrasted with already published multistep routes.