A class of benzofuranoindoline-bearing heptacyclic fungal RiPPs with anticancer activities

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a promising source of new pharmaceuticals, yet the therapeutic potential of fungal RiPPs remains largely underexplored. Here we report asperigimycins as a distinct class of fungal RiPPs, featuring a unique heptacyclic scaffold consisting of a benzofuranoindoline core and three additional macrocycles, primarily assembled by six distinct fungi-specific DUF3328 oxidases. Inspired by the enhancement of anticancer activity through the N-terminal pyroglutamate in naturally occurring asperigimycins C and D, we chemically modify the inactive asperigimycin B with a series of lipid substitutions at its N-terminus. A derivative with a C-11 linear fatty acid, 2-L₆, achieves nanomolar anticancer potency comparable to that of clinically approved antileukemia drugs. High-throughput CRISPR screening identifies the SLC46A3 transporter as a critical factor mediating 2-L₆ cellular uptake into human cells. Our findings highlight the promise of engineering asperigimycins as therapeutic leads for cancer treatment.