Single‐Component Dual‐Functional Autoboost Strategy by Dual Photodynamic and Cyclooxygenase‐2 Inhibition for Lung Cancer and Spinal Metastasis

Coloading adjuvant drugs or biomacromolecules with photosensitizers into nanoparticles to enhance the efficiency of photodynamic therapy (PDT) is a common strategy. However, it is difficult to load positively charged photosensitizers and negatively charged adjuvants into the same nanomaterial and further regulate drug release simultaneously. Herein, a single‐component dual‐functional prodrug strategy is reported for tumor treatment specifically activated by tumor microenvironment (TME)‐generated HOCl. A representative prodrug (DHU‐CBA2) is constructed using indomethacin grafted with methylene blue (MB). DHU‐CBA2 exhibited high sensitivity toward HOCl and achieved simultaneous release of dual drugs in vitro and in vivo. DHU‐CBA2 shows effective antitumor activity against lung cancer and spinal metastases via PDT and cyclooxygenase‐2 (COX‐2) inhibition. Mechanistically, PDT induces immunogenic cell death but stimulates the gene encoding COX‐2. Downstream prostaglandins E2 and Indoleamine 2,3 dioxygenase 1 (IDO1) mediate immune escape in the TME, which is rescued by the simultaneous release of indomethacin. DHU‐CBA2 promotes infiltration and function of CD8+ T cells, thus inducing a robust antitumor immune response. This work provides an autoboost strategy for a single‐component dual‐functional prodrug activated by TME‐specific HOCl, thereby achieving favorable tumor treatment via the synergistic therapy of PDT and a COX‐2 inhibitor. This article presents a single‐component, dual‐functional prodrug, DHU‐CBA2, designed to simultaneously release indomethacin and methylene blue (MB) in response to HOCl. Both in vitro and in vivo studies demonstrate the high sensitivity of DHU‐CBA2 toward HOCl. The prodrug triggers a potent antitumor immune response by combining PDT and cyclooxygenase‐2 inhibition, and exhibits effective antitumor activity.