Mitochondria-targeted nanoplatforms building for in situ ROS generating photodynamic tumor therapy through reinforcing mitochondria apoptotic pathway

Mitochondria-targeted photodynamic therapy (PDT) represents an attractive therapeutic strategy for antitumor therapy. There is growing evidence indicating that in situ generation of reactive oxygen species (ROS) in mitochondria plays a critical role in significant mitochondrial dysfunction and cell apoptosis. Nevertheless, survivin, a member of the inhibitor of apoptosis protein (IAP) family, is overexpressed by PDT stimulation, which inhibit cysteine aspartic acid specific protease-9 (caspase-9) activation and inhibits apoptosis. The corresponding overexpression of Livin protein in tumor cells can inhibit cysteine aspartic acid specific protease-3 (caspase-3) activity, leading to apoptosis inhibition and promoting tumorigenesis and tumor progression. Thus, a precise combination of mitochondria-targeted photodynamic photosensitizers and IAP inhibitor is expected to significantly augment the PDT efficacy. For proof-of-concept, a therapeutic nanoplatform MSNs/GM/I3C-BSA/MnO2-IR775 (MGIBR) was ingeniously constructed for synergistic cancer therapy. MGIBR can effectively target mitochondria due to the presence of IR775. Under NIR irradiation, MGIBR can generate in situ 1O2 in mitochondria. Importantly, geldanamycin (GM) and indole-3-carbinol (I3C) can inhibit IAP, synergistic enhance PDT and activate mitochondrial apoptosis pathways, leading to effectively cell death. Such a strategy of MGIBR enabled mitochondrial dysfunction based on in situ generation of ROS in mitochondria and IAP inhibitor synergistically, provides a promising paradigm for highly effective cancer therapeutics.