In Vivo Efficacy of Natural Product‐Inspired Irreversible Kinase Inhibitors

Hypothemycin and related resorcylic acid lactones (RAL) bearing a cis ‐enone moiety have emerged as an alternative pharmacophore to heterocyclic motifs for kinase inhibition, and are endowed with a unique selectivity filter based on the irreversible reaction with a subset of the kinome bearing a suitably positioned cysteine residue. Two prototypical examples of “edited” RAL were evaluated for antitumoral, antimetastatic and antiangiogenic efficacy in an orthotopic murine renal cell carcinoma (RENCA) model. Both compounds ( 3 and 5 ) are good inhibitors of VEGFRs in vitro, and inhibited tumor growth in vivo with comparable efficacy to sunitinib, an FDA‐approved VEGFRs inhibitor. Compound 3 promoted lung metastasis to a similar extent as sunitinib, while compound 5 strongly inhibited lung metastasis. This study attests to the potential of irreversible kinase inhibitors and molecular editing of natural pharmacophores and provides encouraging results to a clinically significant problem.