Tumor-Activated Benzothiazole Inhibitors of Stearoyl-CoA Desaturase.

A series of N-acyl benzothiazoles shows selective and potent cytotoxicity against cancer cell lines expressing cytochrome P450 4F11. A prodrug form is metabolized by cancer cells into an active inhibitor of stearoyl-CoA desaturase (SCD). Substantial variation on the acyl portion of the inhibitors allowed the identification of (R)-27, which balanced potency, solubility, and lipophilicity to allow proof-of-concept studies in mice. The prodrugs were activated inside the tumor, where they can arrest tumor growth. Together, these observations offer promise that a tumor-activated prodrug strategy might exploit the essentiality of SCD for tumor growth, while avoiding toxicity associated with systemic SCD inhibition.