Multidrug resistance of tumor cells has greatly limited the chemotherapy effect. The development of reliable strategies to deal with tumor multidrug resistance is highly desirable for tumor therapy. In this work, a near-infrared II (NIR II) luminogen was rationally designed and prepared, which could act as a photothermal reagent to reverse the drug resistance of tumor cells by reducing the related protein expression, achieving a high inhibition efficiency with the synergistic effect of chemotherapeutic drugs. By the selection of a strong electron-withdrawing unit, the emission peak of the luminogen could reach 973 nm. Moreover, this luminogen shows outstanding photothermal conversion ability and improved thermal stability compared to ICG. Notably, after the photothermal treatment of drug-resistant tumor cells by the NIR II luminogen, the antitumor efficiency of chemotherapeutic drugs, including paclitaxel, cis-platinum, and doxorubicin, was significantly enhanced. The mechanism exploration revealed that drug resistance-related proteins were remarkably reduced, making the cells more sensitive toward drugs. Thus, this strategy demonstrated a promising and reliable approach to reverse the drug resistance of tumor cells for efficient tumor inhibition in the clinic.
Keywords: NIR II; drug-resistant tumor; fluorescent luminogen; photothermal therapy; reversal.