Discovery of IPN60090, a Clinical Stage Selective Glutaminase-1 (GLS-1) Inhibitor with Excellent Pharmacokinetic and Physicochemical Properties.

Inhibition of glutaminase-1 (GLS-1) hampers the proliferation of tumor cells reliant on glutamine. Known glutaminase inhibitors have potential limitations, and in vivo exposures are potentially limited due to poor physicochemical properties. We initiated a GLS-1 inhibitor discovery program focused on optimizing physicochemical and pharmacokinetic properties, and have developed a new selective inhibitor, compound 27 (IPN60090), which is currently in phase 1 clinical trials. Compound 27 attains high oral exposures in preclinical species, with strong in vivo target engagement, and should robustly inhibit glutaminase in humans.

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.

Novel antibiotics: C-2 symmetrical macrocycles inhibiting Holliday junction DNA binding by E. coli RuvC.

Holliday junctions (HJs) are formed as transient DNA intermediates during site-specific and homologous recombination. Both of these genetic exchange pathways are critical for normal DNA metabolism and repair. Trapping HJs leads to bacterial cell death by preventing proper segregation of the resulting interlinked chromosomes. Macrocyclic peptides designed to target this intermediate were synthesized with the goal of identifying compounds with specificity for this unique molecular target. We discovered ten macrocycles, both hexameric and octameric peptides, capable of trapping HJs in vitro. Those macrocycles containing tyrosine residues proved most effective. These data demonstrate that C-2 symmetrical macrocycles offer excellent synthetic targets for the development of novel antibiotic agents. Furthermore, the active compounds identified provide valuable tools for probing different pathways of recombinational exchange.

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]