Drug-likeness defects drive carrier-free cyanine-PROTAC self-assembly for tumor-specific protein degradation.

Abstract

Proteolysis-targeting chimeras (PROTACs) offer a powerful strategy for targeted protein degradation but suffer from poor solubility, bioavailability, and in vivo distribution due to their "beyond rule-of-five" physicochemical properties, severely limiting clinical translation. Here, we transform these intrinsic drug-likeness liabilities into a driving force for molecular self-assembly by developing a carrier-free nanoplatform in which PROTACs spontaneously co-assemble with cyanine dyes, including IR783 and the clinically approved indocyanine green (ICG). This strategy generates stable supramolecular assemblies with ultra-high PROTAC loading (up to 70 wt%) without the need for exogenous carriers, while imparting intrinsic NIR fluorescence for real-time, non-invasive in vivo tracking. The assemblies undergo stimuli-responsive disassembly upon ultrasound or X-ray irradiation, enabling spatiotemporally controlled PROTAC release within tumors. Incorporation of diselenide-bridged cyanine derivatives further confers radiosensitization capability, allowing synergistic combination with radiotherapy. In vivo studies demonstrate efficient tumor accumulation, robust target protein degradation, and potent antitumor efficacy. Collectively, this work establishes a versatile supramolecular strategy that directly addresses the long-standing delivery challenges of PROTACs and advances precise, controllable oncological therapy.