Drug-independent NADPH-consuming micelles collaborate with ROS-generator for cascade ferroptosis amplification by impairing redox homeostasis

Ferroptosis as promising antitumor therapy strategy could be comprised by intracellular antioxidants, especially GSH and thioredoxin (Trx). They are both cofactors of Gpx4, the enzyme catalyzing the production of lipid peroxides to relieve oxidative stress, which drives the acquired ferroptosis resistance in tumors. Herein, the NADPH-consuming micelles are specially designed, which could collaborate with the ROS generating photodynamics therapy (PDT) by depleting intracellular GSH and Trx under hypoxia condition, resulting in ruined redox homeostasis and the final cascade amplified ferroptosis. The tailored micelle was briefly prepared by conjugating hypoxia-sensitive segment p-nitrobenzyl chloroformate (PNZ-Cl) to the hydrophilic chitosan (CS), the resulting micelle was further modified with photosensitizer Ce6 via PEG linkage. When receiving laser irradiation, the photosensitizer would generate ROS and consume oxygen in the meanwhile. The resulting anabatic hypoxia in turns promote the NTR-catalyzed electron-accepting response of micelles, with evidently enhanced NADPH consumption and ultimately ruined redox homeostasis, contributing to cascade amplified ferroptosis with robust ROS. Most importantly, the accompanied immunogenic cell death (ICD) and releasing danger-associated molecular patterns (DAMPs) could boost dendritic cells (DCs) maturation and the subsequent T-cell-mediated profound immune response. Collectively, the work excavates the other biochemical reaction during the hypoxia-sensitive process of C-N-Ce6 by diminishing intracellular GSH and Trx, providing a candidate of ferroptosis inducers against solid tumors.

Near-infrared light-triggered synergistic antitumor therapy based on hollow ZIF-67-derived Co3S4-indocyanine green nanocomplex as a superior reactive oxygen species generator

Reactive oxygen species (ROS) with strong oxidability have been considered as effective agents for antitumor therapy through oxidative damage to lipids, proteins, DNA and RNA. In this work, a multifunctional hollow cobaltosic sulfide (Co₃S₄)/photosensitizer indocyanine green (ICG) nanocomplex (Co₃S₄-ICG) has been synthesized by efficiently loading ICG into the hollow Co₃S₄ to realize synergistic antitumor therapy via chemodynamic therapy (CDT), photodynamic therapy (PDT) and photothermal therapy (PTT) under near-infrared (808 nm) laser irradiation. Co₃S₄ nanoparticles would be degraded in tumor acidic microenvironment into Co²⁺, which locally triggers a Fenton-like reaction to produce cytotoxic hydroxyl radicals (OH) for CDT. Co₃S₄-ICG could also produce singlet oxygen (¹O₂) through a multi-step photochemical process for PDT under 808 nm laser irradiation. The slow release of ICG in the tumor region was achieved due to hollow-structured Co₃S₄ working as nanocarriers, and which has been proved an effective approach for combined CDT/PDT. In addition, Co₃S₄-ICG showed high photothermal conversion efficiency (40.5%) for PTT, and excellent OH generation capability via photothermal-improved Fenton reaction, leading to the synergistically improved antitumor efficacy. In vitro and in vivo experimental results confirm that the combined PTT/PDT/photothermal-enhanced CDT therapy can effectively ablate tumors with a negligible systemic toxicity. This work provides a valuable strategy for designing and constructing of a multifunctional nanoplatform for synergistic antitumor therapy of solid tumors.

Light-Induced Reactive Oxygen Species (ROS) Generator for Tumor Therapy through an ROS Burst in Mitochondria and AKT-Inactivation-Induced Apoptosis

Mitochondria are identified as a valuable target for cancer therapy owing to their primary function in energy supply and cellular signal regulation. Mitochondria in tumor cells are depicted by excess reactive oxygen species (ROS), which lead to numerous detrimental results. Hence, mitochondria-targeting ROS-associated therapy is an optional therapeutic strategy for cancer. In this contribution, a light-induced ROS generator (TBTP) is developed for evaluation of the efficacy of mitochondria-targeting ROS-associated therapy and investigation of the mechanism underlying mitochondrial-injure-mediated therapy of tumors. TBTP serves as an efficient ROS generator with low cytotoxicity, favorable biocompatibility, excellent photostability, mitochondria-targeted properties, and NIR emission. In vivo and in vitro experiments reveal that TBTP exhibits effective anticancer potential. ROS generated from TBTP could destroy the integrity of mitochondria, downregulate ATP, decrease the mitochondrial membrane potential, secrete Cyt-c into cytoplasm, activate Caspase-3/9, and induce cell apoptosis. Moreover, RNA-seq analysis highlights that an ROS burst in mitochondria can kill tumor cells via inhibition of the AKT pathway. All these results prove that mitochondrial-targeted ROS-associated therapy hold great potential in cancer therapy.

Acid-activated ROS generator with folic acid targeting for bacterial biofilm elimination

Many medical and chemical applications require the precise supply of antimicrobial components in a controlled manner at the location of mature biofilm deposits. This work reports a facile strategy to fabricate nanoscale metal-organic frameworks (NMOFs) coencapsulating the antibacterial ligand (lysine carbon dots, Lys-CDs) and targeted drug (folic acid, FA) in one pot to improve antibiofilm efficiency against established biofilms. The resulting products are characterized by transmission electron microscopy, field-emission scanning electron microscopy, powder x-ray diffraction, and ultraviolet-visible spectroscopy. The results show that Lys-CDs could coordinate with Zn²⁺ and the adding of FA inhibits the coordination of Lys-CDs with central ions of Zn. The Lys-CDs and FA are successfully exposed with the NMOFs disintegrating in the acid environment of bacterial metabolites. We are surprised to find a sharp increase of reactive oxygen species (ROS) inside the bacterial cells by FA functionalizing NMOFs, which undoubtedly enhance the antibacterial and antibiofilm activity. The as-synthesized ZIF-8-based nanocomposites also show the peroxidase-like activity in an acid environment, and produce extremely active hydroxyl radicals resulting in the improved antibacterial and antibiofilm activity. The possible mechanisms of antibacterial activities indicate that the presence of FA is significant in the sense of targeting bacteria. This study shows a novel approach to construct acid stimulation supply system which may be helpful for the research of antibiofilms.