Photoactivated full-API nanodrug (FAND): harnessing transition metal complexes and MTH1 inhibitor for enhanced DNA damage in cancer cells

The effectiveness of photodynamic therapy (PDT) has been greatly restricted by the hypoxic tumor microenvironment and the susceptible resistance of monotherapy. Although nanodrugs based on transition metal complexes capable of integrating PDT with photoactivated chemotherapy (PACT) have garnered tremendous attention as promising candidates for overcoming the above limitations, the therapeutic efficacy of these nanodrugs is still hampered by inadequate loading of active pharmaceutical ingredients (APIs) and the inherent ability of cancer cells to repair damaged DNA. Herein, we developed a photoactivated full-API nanodrug, Ru-T FAND, by one-step self-assembly of RuDPB and TH287. By virtue of its 100 wt% API content and favorable stability in water, the Ru-T FAND exhibited improved cellular uptake behavior and intracellular ¹O₂ generation. Attractively, the Ru-T FAND with triple anti-cancer modalities can photogenerate ¹O₂, photo-release DPB ligand and inhibit the repair of DNA damage, ultimately enhancing its phototherapeutic effect on cancer cells. Importantly, the uncaged DPB ligand from RuDPB emits red fluorescence, enabling real-time monitoring of the drug's absorption, distribution and efficacy. Collectively, the presented photoactivated Ru-T FANDs with multiple anti-cancer mechanisms will expand new horizons for the development of safe, efficient and synergistic tumor phototherapy strategies.