Cascade-Targeted Type I/II Sensitizer Enabled by Enzyme-Instructed Self-Assembly for Amplified Sono-Photodynamic Tumor Therapy.

Abstract

Sono-photodynamic therapy (SPDT) offers a non-invasive, spatiotemporally precise approach to cancer treatment, but its effectiveness is still limited by poor tumor specificity and penetration. To address this, we developed a cascade-targeted type I/II sensitizer, Ce6-TPP-Phe-Tyr (CTPT), which integrates chlorin e6 (Ce6), triphenylphosphonium (TPP), and a phospho-peptide motif for precise tumor targeting and potent SPDT. Upon dephosphorylation by tumor-overexpressed alkaline phosphatase (ALP), CTPT undergoes enzyme-instructed self-assembly (EISA) into nanoparticles (CTPT NPs), promoting their accumulation and retention in tumors. The TPP cations then guide these nanoparticles to mitochondria, concentrating the therapeutic payload at this critical organelle for cellular energy metabolism. Subsequent ultrasound/laser irradiation further enhances tissue permeability and triggers the generation of both type I and type II reactive oxygen species (ROS), leading to potent oxidative damage. This integrated strategy of EISA and mitochondria-targeted SPDT achieved approximately 86% tumor regression in ALP-overexpressing xenografts. This strategy minimizes systemic toxicity and achieves potent tumor regression by cascade delivery of the therapeutic agent, thereby significantly enhancing the precision and efficacy of SPDT.