Near-Infrared Fluorescent Heptamethine Cyanine Dyes for COX-2 Targeted Photodynamic Cancer Therapy

Advancing cancer therapy with a heptamethine carbocyanine dye-conjugated radionuclide drug

Malignant tumors pose substantial treatment challenges due to their heterogeneity, metastatic potential, and therapeutic resistance, underscoring the urgent need for more effective treatment options. In this study, a novel radionuclide drug conjugate (RDC) was developed and characterized employing a tumor-targeting heptamethine carbocyanine dye (DZ) for its high specificity and favourable safety profile. The RDC, DOTA-DZ-HX, was synthesized by conjugating DZ with dodecane tetraacetic acid (DOTA) through a dipeptide linker. The anti-tumor efficacy and biodistribution of [177Lu]Lu-DOTA-DZ-HX were assessed in H1975 and HeLa xenograft models. [177Lu]Lu-DOTA-DZ-HX showed high stability, specific tumor accumulation, and substantial radioactivity retention at the tumor site for seven days. Biodistribution analysis revealed that the drug exhibited prolonged blood circulation with gradual clearance. Additionally, [177Lu]Lu-DOTA-DZ-HX could effectively and selectively inhibit tumor growth, as evidenced by a significant reduction in tumor volume. These findings suggest that heptamethine carbocyanine dye-directed radionuclide targeting could provide an effective treatment for cancer and potentially other malignancies, representing a significant advancement in cancer therapy.

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.