Insulin‐like Growth Factor 2‐Tagged Aptamer Chimeras (ITACs) Modular Assembly for Targeted and Efficient Degradation of Two Membrane Proteins

Abstract Overexpression of pathogenic membrane proteins drives abnormal proliferation and invasion of tumor cells. Various strategies to durably knockdown membrane proteins with heterobifunctional degraders have been successfully developed, including LYTAC, KineTAC, and AbTAC. However, challenges including complicated synthetic procedures and the inability to simultaneously degrade multiple pathogenic proteins still exist. Herein, we developed insulin‐like growth factor 2 (IGF2)‐tagged aptamer chimeras (ITACs) that link the cell‐surface lysosome‐targeting receptor IGF2R and membrane proteins of interest (POIs) based on specific recognition of aptamers to the POIs and high‐affinity binding of IGF2 to IGF2R. We demonstrated that ITACs exhibit robust degradation efficiency of various membrane proteins in multiple cell lines. Furthermore, systematic studies revealed that a moderate cell‐surface IGF2R level is responsible for the excellent degradation performance of ITACs. Importantly, we further established a modular assembly strategy that allows assembly of one IGF2 with two aptamers with precise stoichiometry (dITACs), enabling cooperative and simultaneous degradation of two membrane proteins. This work provides an efficient and facile target membrane protein degradation platform and will shed light on the treatment of diseases related to the overexpression of membrane proteins.