Autophagy-Activating Nanoautophagosome-Tethering Compounds for Targeted Protein Degradation Specifically in Tumor Cells

Autophagosome-tethering compounds (ATTECs) represent an emerging targeted protein degradation (TPD) technology that directly draws intracellular proteins of interest (POIs) into autolysosomes. Although ATTECs are currently dominated by small molecules, the poor cell-type specificity and pharmacokinetic profile limit their applications in certain diseases. Moreover, the suboptimal intrinsic autophagic activity of cells affects the ATTECs-mediated degradation capability. Here we develop a nano-ATTEC system using our unique mixed-shell polymeric micelle (MSPM)-based nanoplatform for tumor-specific degradation of POIs. We demonstrate that the MSPMs-based nano-ATTEC is efficiently taken up by tumor cells in the acidic tumor microenvironment and to degrade POIs, rather than by normal cells under physiological conditions. More importantly, we find that this nano-ATTEC can not only target autolysosomes but also robustly enhance the autophagy activity, thereby establishing a positive feedback mechanism based on the autophagy pathway for efficient degradation of POIs. We believe that this MSPMs-based nano-ATTEC will find broad applications in tumor therapy.