Boosted photocatalytic activity induced NAMPT-Regulating therapy based on elemental bismuth-humic acids heterojunction for inhibiting tumor proliferation/migration/inflammation.

Due to the highly complex biological formation procedure, tumor is still difficult to be treated efficiently and always associated with proliferation, migration and inflammation during treatment. Herein, a novel strategy of boosted photocatalytic activity induced NAMPT-regulating therapy is used for tumors inhibition based on FK866 loaded bismuth-humic acids heterojunction (Bi-HA/FK866). With the reduction function of HA, Bi (Ⅲ) can be reduced to elemental Bi, which can be excited by NIR laser to form electron-hole pair due to the narrow bandgap. Moreover, the coated HA and Bi could form a heterojunction structure, which could decrease the electron-hole recombination, and further boost the photocatalytic activity, leading to highly efficient ROS generation and GSH depletion. The resulted ROS could induce DNA damage of the tumor cells, thus enhancing the sensitivity to the inhibitor of NAMPT (FK866) to downregulate NAD/ERK/NF-κB signal pathways, and eventually simultaneously prevent cancer progression. Moreover, the decreased NAD could downregulate NADPH and further suppress the innate antioxidant defense system by inhibiting reduction of GSSG. The boosted photocatalytic activity induced NAMPT-regulating therapy offers a promising way to address the important issue of penetration depth limitation induced cancer relapse and migration, providing more possibilities toward successful clinical application.

Ultra-small Bi2S3 nanodot-doped reversible Fe(ii/iii)-based hollow mesoporous Prussian blue nanocubes for amplified tumor oxidative stress-augmented photo-/radiotherapy.

Improving the generation of reactive oxygen species (ROS) while consuming glutathione (GSH) is the main method for amplifying intracellular oxidative stress. However, in previous studies, it was normally necessary to combine two or more materials to achieve the effect of destroying the intracellular redox homeostasis. This made the preparation process relatively complicated. Herein, we designed ultra-small bismuth sulfide quantum dot (Bi2S3 QD)-doped hollow mesoporous Prussian blue (HMPB) (HMPB/Bi2S3) nanocubes for amplified tumor oxidative stress to augment photo-/radiotherapy. In addition to being photothermal materials, Prussian blue can be used as both a catalyst for the Fenton reaction and a consumer of GSH due to the multivalent state of iron. Ferrous ions (Fe(ii)) can produce toxic ROS-hydroxyl radicals (˙OH) with abundant hydrogen peroxide in the tumor cells by the Fenton reaction. Meanwhile, ferric ions (Fe(iii)) can oxidize the intracellular GSH to GSSG, thus depleting the concentration of GSH inside tumors. As a result, oxidative stress imbalance could be induced by the reversible redox property of Fe(ii/iii), thereby causing DNA damage and increasing the cell membrane permeability to realize enhanced photo-/radiotherapy. As a sensitizer for radiotherapy, ultra-small Bi2S3 QDs (3-5 nm) are doped in HMPB, thus improving the therapeutic effect by prolonging blood circulation and reducing systemic toxicity via kidney metabolism. Therefore, such a reversible HMPB/Bi2S3 nanocube is a promising therapeutic agent for amplified tumor oxidative stress to augment photo-/radiotherapy, which might show further applications in nanomedical science.