Discovering and harnessing oxidative enzymes for chemoenzymatic synthesis and diversification of anticancer camptothecin analogues

Abstract

Semi-synthetic derivatives of camptothecin, a quinoline alkaloid found in the Camptotheca acuminata tree, are potent anticancer agents. Here we discovered two C. acuminata cytochrome P450 monooxygenases that catalyze regio-specific 10- and 11-oxidations of camptothecin, and demonstrated combinatorial chemoenzymatic C-H functionalizations of the camptothecin scaffold using the new enzymes to produce a suite of anticancer drugs, including topotecan (Hycamtin®) and irinotecan (Camptosar®). This work sheds new light into camptothecin metabolism, and represents greener approaches for accessing clinically relevant camptothecin derivatives.

Camptothecin derivatives are precursors of potent anticancer agents, but their biosynthesis remains largely unknown. Here two cytochrome P450 monooxygenases are shown to regiospecifically oxidize camptothecin, yielding 10- and 11- hydroxylated derivatives, which are subsequently used to produce a suite of known anticancer drugs and derivatives.