A carrier-free metal-phenolic network with enhanced ferroptosis-immunotherapy for overcoming tumor resistance and metastasis

The development of multidrug resistance (MDR) is the primary contributor to the failure of cancer treatment, ultimately leading to tumor recurrence and metastasis. Ferroptosis, an iron-dependent cell death form related to the accumulation of lipid peroxidation (LPO), has the potential to circumvent MDR. Furthermore, recent breakthroughs have confirmed that the inhibition of cyclooxygenase-2 (COX-2) not only facilitate LPO and ferroptosis, but also suppress the expression of p-glycoprotein. Therefore, the combination of immunogenic ferroptosis with COX-2 inhibitors may be an enticing approach for overcoming tumor resistance and metastasis. Herein, polyphenolic COX-2 inhibitors are first screened using molecular docking, enzyme-linked immunosorbent assay, and combination index analysis. Then, a carrier-free metal-phenolic networks are constructed based on the coordination between polyphenolic COX-2 inhibitors and Fe3+, and DOX and dopamine-modified hyaluronic acid are directly decorated using a one-pot process. The nanosystem can selectively inhibit the COX-2 pathway, thereby suppressing the expression of p-glycoprotein and enhancing Fe3+-induced ferroptosis; Additionally, the nanosystem demonstrates excellent photothermal performance, promoting ferroptosis and synergistically triggering strong immune responses against tumor metastasis. The RNA-seq analysis further confirmes the transcriptomic alterations in drug resistance and ferroptosis pathways induced by the nanosystem. Taken together, this study provides a promising strategy for efficient cancer treatment.