Fungal ribosomally synthesized and post-translationally modified peptides (F-RiPPs): Biosynthesis, genome mining, structural diversity, and translational potential as targeted anticancer ADC payloads.

Fungal RiPPs (F-RiPPs) are a diverse class of natural products that have transitioned from notorious mycotoxins to promising therapeutic agents. This review summarizes the biosynthesis, structural diversity, and biomedical relevance of major F-RiPP families, including amatoxins and phallotoxins, dikaritins, epichloëcyclins, and recently identified asperigimycins. Key post-translational modifications, such as peptide cyclization, N-methylation, and oxidative cross-linking, enhance stability, cellular uptake, and biological activity. Recent advances in genome mining and molecular networking have accelerated the discovery of cryptic F-RiPP biosynthetic gene clusters and enabled functional validation through heterologous expression in fungal and yeast hosts. Pharmacologically, F-RiPPs act through distinct mechanisms, including inhibition of RNA polymerase II, disruption of cytoskeletal dynamics, membrane perturbation, and induction of apoptosis, often with high potency in preclinical cancer models. Importantly, amanitin-based antibody-drug conjugates have entered early-phase clinical trials, demonstrating the translational potential of this peptide class. The review concludes by discussing current challenges in discovery and production, and emerging strategies to expand F-RiPPs as a new source of targeted anticancer therapeutics.