A poly-ADP-ribose polymer-based antibody-drug conjugate.

Protein poly-ADP-ribosylation (PARylation) plays vital roles in many aspects of physiology and pathophysiology. This posttranslational modification is catalyzed by poly-ADP-ribose polymerases (PARPs) through additions of ADP-ribose from nicotinamide adenine dinucleotide (NAD+) to protein residues, forming linear or branched poly-ADP-ribose (PAR) polymers. In this study, we explored a new concept of utilizing functionalized PAR polymers for targeted drug delivery. This was achieved by rapid and efficient generation of auto-PARylated PARP1 with 3'-azido ADP-riboses and subsequent conjugations of anti-human epidermal growth factor receptor 2 (HER2) antibodies and monomethyl auristatin F (MMAF) payloads. This designed PARylated PARP1-antibody-MMAF conjugate could potently kill HER2-expressing cancer cells in high specificity. This proof-of-principle work demonstrates the feasibility of production of PAR polymer-based antibody-drug conjugate and its application in targeted delivery. The PAR polymer-based conjugates may lead to new types of therapeutics with potentially improved physicochemical and pharmacological properties.