B7H3 targeting gold nanocage pH-sensitive conjugates for precise and synergistic chemo-photothermal therapy against NSCLC

BACKGROUND

The combination of drug delivery with immune checkpoint targeting has been extensively studied in cancer therapy. However, the clinical benefit for patients from this strategy is still limited. B7 homolog 3 protein (B7-H3), also known as CD276 (B7-H3/CD276), is a promising therapeutic target for anti-cancer treatment. It is widely overexpressed on the surface of malignant cells and tumor vasculature, and its overexpression is associated with poor prognosis. Herein, we report B7H3 targeting doxorubicin (Dox)-conjugated gold nanocages (B7H3/Dox@GNCs) with pH-responsive drug release as a selective, precise, and synergistic chemotherapy-photothermal therapy agent against non-small-cell lung cancer (NSCLC).

RESULTS

In vitro, B7H3/Dox@GNCs exhibited a responsive release of Dox in the tumor acidic microenvironment. We also demonstrated enhanced intracellular uptake, induced cell cycle arrest, and increased apoptosis in B7H3 overexpressing NSCLC cells. In xenograft tumor models, B7H3/Dox@GNCs exhibited tumor tissue targeting and sustained drug release in response to the acidic environment. Wherein they synchronously destroyed B7H3 positive tumor cells, tumor-associated vasculature, and stromal fibroblasts.

CONCLUSION

This study presents a dual-compartment targeted B7H3 multifunctional gold conjugate system that can precisely control Dox exposure in a spatio-temporal manner without evident toxicity and suggests a general strategy for synergistic therapy against NSCLC.

The effect of linkers on the self-assembling and anti-tumor efficacy of disulfide-linked doxorubicin drug-drug conjugate nanoparticles

Drug-drug conjugate nanoparticles (DDC NPs) is a potential method for overcoming poor solubility and nonspecific action in cancer therapy, which is based on its high drug loading efficiency and passive tumor-target properties. Our laboratory has prepared DOX-SS-DOX NPs based on disulfide-linked doxorubicin (DOX) drug-drug conjugate, which showed well physical stability and similar anti-tumor efficacy as liposomes. However, how structures of DDCs influence the self-assembling and anti-tumor efficacy is still seldom clarified and needs further investigation. Here, we discussed the role of linker types, length and linkage site in the NPs self-assembling and anti-tumor efficacy. A series of DOX prodrugs were prepared and all the prodrugs could self-assemble into NPs except DOX-SS-DOX (2), indicating the linker length played an important role during self-assembling process. The linkage sites and types of linker exhibited great influence on in vitro cytotoxicity and in vivo anti-tumor efficacy, particularly, modification on C-14 hydroxyl was more efficient for DOX release than on amino group. Besides, disulfide-bond was not cleaved and DOX-SH release did not occur in the metabolism process. The function of disulfide-bond was to enhance the release of DOX in the hydrolysis process. These findings is meaningful for effective prodrug NPs design for therapeutics.