Design and Characterization of the First Selective and Potent Mechanism-Based Inhibitor of Cytochrome P450 4Z1

Mammary-tissue-restricted
cytochrome P450 4Z1 (CYP4Z1) has garnered
interest for its potential role in breast cancer progression. CYP4Z1-dependent
metabolism of arachidonic acid preferentially generates 14,15-epoxyeicosatrienoic
acid (14,15-EET), a metabolite known to influence cellular proliferation,
migration, and angiogenesis. In this study, we developed time-dependent
inhibitors of CYP4Z1 designed as fatty acid mimetics linked to the
bioactivatable pharmacophore, 1-aminobenzotriazole (ABT). The most potent analogue, 8-[(1H-benzotriazol-1-yl)­amino]­octanoic
acid (7), showed a 60-fold lower shifted-half-maximal
inhibitory concentration (IC50) for CYP4Z1 compared to ABT, efficient mechanism-based inactivation of the enzyme
evidenced by a KI = 2.2 μM and a kinact = 0.15 min–1, and a
partition ratio of 14. Furthermore, 7 exhibited low off-target
inhibition of other CYP isozymes. Finally, low micromolar concentrations
of 7 inhibited 14,15-EET production in T47D breast cancer
cells transfected with CYP4Z1. This first-generation, selective mechanism-based
inhibitor (MBI) will be a useful molecular tool to probe the biochemical
role of CYP4Z1 and its association with breast cancer.