Cooperatively Designed Aptamer-PROTACs for Spatioselective Degradation of Nucleocytoplasmic Shuttling Protein for Enhanced Combinational Therapy

Nucleocytoplasmic shuttling proteins (NSPs) has emerged as a promising class of therapeutic targets for many diseases including cancer. However, most reported NSPs-based therapies largely rely on small molecule inhibitors with limited efficacy and off-target effects. Proteolysis targeting chimera (PROTAC) represents a revolutionary inhibitory modality for targeted protein degradation with many advantages, including substoichiometric catalytic activity, improved selectivity, and high efficacy. However, the majority of reported PROTACs so far are still limited to the degradation of cytoplasmic proteins and lack of tumor-specific targeting. To realize the full potential of the PROTAC technology and broaden its applications for the degradation of NSPs, we herein report a conceptual approach for the design of a new archetype of PROTAC (denoted as PS-ApTCs) by introducing phosphorothioate-modified AS1411 aptamer to a ligand of the CRBN E3 ligase, realizing tumor-targeting and spatioselective degradation with improved efficacy. We have demonstrated that PS-ApTCs is capable of effectively degrading nucleolin in target cell membrane and cytoplasm but not in the nucleus, in a CRBN- and proteasome-dependent manner. In addition, PS-ApTCs exhibits superior antiproliferation, pro-apoptotic, and cell cycle arrest potencies. Importantly, we demonstrate for the first time that combination of PS-ApTCs-mediated nucleolin degradation with aptamer-drug conjugates-based chemotherapy can enable an AND-gated synergistic effect on tumor inhibition. Collectively, our results suggest that PS-ApTCs possess the ability to expand the PROTACs toolbox to even wider range of targets in subcellular localization and accelerate the discovery of new combinational therapeutic approaches. For Table of Contents Only O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=99 SRC="FIGDIR/small/514682v1_ufig1.gif" ALT="Figure 1"> View larger version (47K): org.highwire.dtl.DTLVardef@ed8331org.highwire.dtl.DTLVardef@1400b91org.highwire.dtl.DTLVardef@1b795a6org.highwire.dtl.DTLVardef@1c1f141_HPS_FORMAT_FIGEXP M_FIG C_FIG