Two-pronged reversal of chemotherapy resistance by gold nanorods induced mild photothermal effect.

Chemotherapy treatment outcomes are severely restricted by multidrug resistance (MDR), in which tumors develop a multiple cross-resistance toward drug involving the pump and nonpump resistance mechanisms, resulting in drug efflux and defending against drug toxicity. Herein, we constructed a pH and near infrared (NIR) light responsive nanomedicine DOX@FG based on gold nanorods (GNRs) that demonstrated the potential to improve chemotherapy outcomes by overcoming MDR. DOX@FG was constructed by conjugating folic acid (FA) and doxorubicin (DOX) derivatives onto GNRs, where the DOX derivatives possessed an acid-labile hydrazone bond. Stimulated by the acidic media in endocytic organelles, DOX@FG exhibited a responsive dissociation for the controlled release of chemotherapeutic DOX. Surprisingly, we found the mild photothermal effect elicited by GNRs under NIR irradiation simultaneously inhibited the pump and nonpump resistance mechanisms, enhancing the intracellular DOX accumulation and sensitizing the cancer cells to DOX, collectively amplify the chemotherapy efficacy and delay the MCF-7/ADR breast tumor growth. This intelligent DOX@FG nanomedicine with the potential for two-pronged reversal of MDR may provide a prospective way to encourage chemotherapy efficacy.