Hit-to-lead optimization and kinase selectivity of imidazo[1,2-a]quinoxalin-4-amine derived JNK1 inhibitors.

As the result of a rhJNK1 HTS, the imidazo[1,2-a]quinoxaline 1 was identified as a 1.6 µM rhJNK1 inhibitor. Optimization of this compound lead to AX13587 (rhJNK1 IC50=160 nM) which was co-crystallized with JNK1 to identify key molecular interactions. Kinase profiling against 125+ kinases revealed AX13587 was an inhibitor of JNK, MAST3, and MAST4 whereas its methylene homolog AX14373 (native JNK1 IC50=47 nM) was a highly specific JNK inhibitor.

Amides of 4-hydroxy-8-methanesulfonylamino-quinoline-2-carboxylic acid as zinc-dependent inhibitors of Lp-PLA2.

AX10479, the phenyl amide of 4-hydroxy-8-methanesulfonylamino-quinoline-2-carboxylic acid, was identified as a Zn(2+)-dependent, 27nM inhibitor of human plasma Lp-PLA(2). Structure-activity relationship studies focused on the AX10479 2-phenylamide group identified equipotent cycloaliphatic amides, an enantioselective preference for chiral amides, and phenyl substitution patterns (e.g., 2-methyl-3-fluoro) that increased potency.

Synthesis and structure-activity relationship of (1-halo-2-naphthyl) carbamate-based inhibitors of KIAA1363 (NCEH1/AADACL1).

KIAA1363 is a serine hydrolase whose activity has been shown to be positively associated with tumor cell invasiveness. Thus, inhibitors of KIAA1363 represent a novel targeted therapy approach towards cancer. AX11890 ((1-bromo-2-naphthyl) N,N-dimethylcarbamate) was identified as a KIAA1363 inhibitor with an IC(50) value of 1.2 µM and was shown using ESI-MS to carbamylate the catalytic residue Ser(191). SAR studies explored both substitution of the 1-bromo group and derivatization of the 6-position. Activity-based protein profiling demonstrated AX13057 inhibited tumor-localized KIAA1363 in SK-OV-3 xenograft-bearing mice.

Amides of xanthurenic acid as zinc-dependent inhibitors of Lp-PLA(2).

AX10185, the phenyl amide of xanthurenic acid, was found to be a sub-100nM inhibitor of Lp-PLA(2). However, in the presence of EDTA the inhibitory activity of AX10185 was extinguished while the enzymatic activity of Lp-PLA(2) did not change. Subsequent metal screening experiments determined the inhibition to be Zn(2+) dependent. Structure-activity relationship studies indicated the presence of the 4-hydroxy group to be critical and selected substituted phenyl, polycyclic, and cycloaliphatic amides of xanthurenic acid to be well tolerated.

Synthesis and optimization of 2-pyridin-3-yl-benzo[d][1,3]oxazin-4-one based inhibitors of human neutrophil elastase.

The hit-to-lead optimization of the HNE inhibitor 5-methyl-2-(2-phenoxy-pyridin-3-yl)-benzo[d][1,3]oxazin-4-one is described. A structure-activity relationship study that focused on the 5 and 7 benzoxazinone positions yielded the optimized 5-ethyl-7-methoxy-benzo[d][1,3]oxazin-4-one core structure. 2-[2-(4-Methyl-piperazin-1-yl)-pyridin-3-yl] derivatives of this core were shown to yield HNE inhibitors of similar potency with significantly different stabilities in rat plasma.

Synthesis of second-generation sansalvamide A derivatives: novel templates as potential antitumor agents.

We report the synthesis of 34 second-generation Sansalvamide A derivatives. San A derivatives have unique anticancer properties and target multiple cancers, including colon, pancreatic, breast, prostate, and melanoma. As novel templates, the derivatives described herein explore the role of stereochemistry, amide bond geometry, transannular hydrogen bonding, and polarity on antitumor potency. Testing the chemotherapeutic activity of these derivatives against multiple cancer cell lines will provide clear structural motifs and identify conformational space that is important for cytotoxicity. The 34 compounds presented are divided into six series, where five series involve the insertion of D-amino acids in conjunction with four structural features at each of the five positions of the macrocycle. The sixth series involves comparison between all L- and all D-amino acid derivatives with N-methyls placed at each position around the macrocyclic core. The four structural features explored in conjunction with D-amino acids include N-methyl amino acids, aromatic amino acids, polar amino acids, and hydrophobic alkyl amino acids.

Synthesis of Sansalvamide A derivatives and their cytotoxicity in the MSS colon cancer cell line HT-29.

We report the synthesis of thirty-six Sansalvamide A derivatives, and their biological activity against colon cancer HT-29 cell line, a microsatellite stable (MSS) colon cancer cell-line. The thirty-six compounds can be divided into three subsets, where the first subset of compounds contains L-amino acids, the second subset contains D-amino acids, and the third subset contains both D- and L-amino acids. Five compounds exhibited excellent inhibitory activity (>75% inhibition). The structure-activity relationship (SAR) of the compounds established that a single D-amino acid in position 2 or 3 gave up to a 10-fold improved cytotoxicity over Sansalvamide A peptide. This work highlights the importance of residues 2 and 3 and the role of D-amino acids in the extraordinary SAR for this compound class.

Synthesis and cytotoxicity of novel sansalvamide A derivatives.

Described are the syntheses of 14 derivatives of the natural product Sansalvamide A, where two are more active against HCT 116 colon cancer cell lines than the natural product. These derivatives were synthesized using a combinatorial-type strategy that permits elucidation of the amino acid role in the cytotoxicity, and they lay the groundwork for development of new anticancer agents. [structure: see text]