Biomimetic Cascade-Targeting Drug Delivery System for Reversing Chemoresistance in Osteosarcoma

Osteosarcoma (OS) remains the most prevalent primary malignant bone tumor in adolescents, with chemotherapy resistance significantly limiting the efficacy of current treatments. To address the challenges of chemoresistance driven by DNA repair mechanisms and drug efflux, we developed a biomimetic cascade-targeting drug delivery system, TAT-mPDO@cRGD-M. This system combines a polydopamine (mPDA) core with strong photothermal and drug-loading capacities, enabling the co-delivery of cisplatin (CDDP) and olaparib (OLA). Surface functionalization with the nuclear localization peptide TAT and cloaking with osteosarcoma cell membranes modified with cRGD peptides allows for selective tumor recognition, nuclear targeting, and stimuli-responsive drug release. Upon near-infrared (NIR) irradiation, the platform enhances DNA damage, suppresses the PI3K-AKT signaling pathway, and promotes apoptosis while inhibiting epithelial-mesenchymal transition (EMT). In vitro and in vivo studies demonstrated that TAT-mPDO@cRGD-M exhibits potent antitumor activity against cisplatin-resistant osteosarcoma, maintaining strong therapeutic efficacy under low-power NIR irradiation without causing significant damage to normal tissues. This study highlights a highly specific and biocompatible therapeutic approach that offers promising potential for overcoming chemotherapy resistance in osteosarcoma and advancing clinical treatment strategies.