Mitochondria are appealing targets in cancer therapy for providing a suitable microenvironment and energy supply. Herein, we constructed a glycosylated poly(amido amine)/celastrol (PAMAM/Cel) complex for hypoxia-activated mitochondria-specific drug delivery and chemothermal therapy to inhibit tumor growth and metastasis. The complex was characterized by high photothermal conversion efficiency, hypoxia-sensitive polyethylene glycol (PEG) outer layer detachment, and alkaline-sensitive drug release. The complex showed specific cellular uptake in glucose transporter 1 (GLUT1)-overexpressing tumor cells and mitochondrial accumulation in a hypoxic environment. Combined with near-infrared (NIR) laser irradiation, the complex exhibited higher cytotoxicity, apoptosis induction, and metastasis inhibition rates due to the synergistic chemothermal effect. Similarly, the complex also targeted tumors and accumulated in mitochondria in tumor-bearing nude mice, resulting in superior inhibitory effects on tumor growth and metastasis as well as low systematic toxicity. Further mechanistic studies discovered that the complex impaired the mitochondrial membrane, reduced adenosine triphosphate (ATP) content, and regulated metastasis-related protein expression. Thus, the present study provides a promising nanomedicine for tumor therapy.
Tao Zhang,Zhenqi Jiang,Ting Xve,Shan Sun,Juan Li,Wenzhi Ren,Aiguo Wu,Pintong Huang
Constructing nanocarriers with high drug loading capacity is a challenge, which limits the effective delivery of drugs to solid tumors. Here, we reported a one-pot synthesis of hollow nanoparticles (NPs) encapsulated by doxorubicin (DOX) and modified with polydopamine (PDA) to form PDA@DOX NPs for breast cancer treatment. PDA@DOX NPs demonstrated exceptionally high capacity (53.16%) for loading DOX. In addition, when PDA@DOX NPs were administered systemically, they exhibited responsive aggregation in the tumor sites and demonstrated a good controlled release effect for DOX due to the weak acidic environment of the tumor sites and targeting near-infrared (NIR) light irradiation. The PDA outer layer absorbed the near-infrared (NIR) light and facilitated simultaneous generation of heat energy for destroying the tumor cells to release the drug upon NIR irradiation. Moreover, this NIR-activated combined/synergistic therapy exhibited remarkably complete tumor growth suppression in a breast cancer mouse model. Importantly, NPs exhibited a good ultrasound performance both in vitro and in vivo, which could monitor the treatment process. In conclusion, this NIR-activated PDA@DOX NP system is demonstrated as a good US-guided combination (chemotherapy + PTT) therapy platform with high loading capacity and controlled drug release characteristics, which is promising for the treatment of breast cancer.