Calcium/Aluminum-Cored Asymmetric Bilayer Nanoparticles for Codelivery of Ziyuglycoside II and PD-L1 siRNA Exert Anti-Breast Tumor Effects

TL;DR

Researchers developed a nanoparticle that combines two treatments for breast cancer, improving tumor targeting and immune response without harming healthy cells.

Contribution

A novel asymmetric bilayer nanoparticle was created to co-deliver a natural compound and PD-L1 siRNA for enhanced breast cancer therapy.

Findings

The nanoparticle showed high tumor targeting and significantly inhibited tumor growth by ~62% in mice.

It enriched T cells in the tumor while reducing immunosuppressive cells, with no organ toxicity observed.

The nanoparticle enhanced systemic exposure of ziyuglycoside II compared to free drug administration.

Abstract

Objectives Breast cancer remains a major cause of female cancer-related deaths, with current therapies limited by poor tumor targeting and an immunosuppressive microenvironment. This study designed CA/ZYII-siP-c-L—an asymmetric lipid bilayer-coated calcium/aluminum (CA)-core nanoparticle—to co-deliver PD-L1 siRNA (siP) and ziyuglycoside II (ZYII) to boost therapeutic efficacy. Methods CA/ZYII-siP-c-L was fabricated through modified microemulsification to first construct the CA cores, followed by thin-film hydration for encapsulation of ZYII within the hydrophobic domain, and via hybridization of the outer lipid layer with DSPE-PEG1000-PAMAM to finally enable specific adsorption of siP. The characterization of CA/ZYII-siP-c-L was performed to get size distribution, zeta potential and in vitro release behavior. In vitro cytotoxicity of the nanoparticles to NIH3T3 and 4T1 cells was detected by the CCK-8 method. The uptake capacity to 4T1 breast cancer cells was determined using inductively coupled plasma optical emission spectrometry and high-performance liquid chromatography. Pharmacokinetic studies and tissue distribution experiments were performed. In BALB/c mice bearing orthotopic 4T1 tumors, efficacy evaluations were conducted with the detection of tumor immune microenvironment; meanwhile, organ damage was evaluated by hematoxylin-eosin staining of major organs and detection of routine biochemical indicators. Results CA/ZYII-siP-c-L was characterized by dynamic light scattering (mean size ~185.7 nm) and zeta potential analysis (~9.35 mV). In vitro, the nanoparticle exhibited low cytotoxicity in NIH3T3 normal cells, high uptake by 4T1 breast cancer cells, and pH-responsive release. For the pharmacokinetic study, CA nanoparticle system could significantly enhance the systemic exposure of ZYII, compared to free ZYII suspension. In BALB/c mice with orthotopic 4T1 tumors, CA/ZYII-siP-c-L accumulation in tumors was 3.5-fold higher than that of free drugs, significantly enriching helper T cells and cytotoxic T lymphocytes while reducing regulatory T cells and suppressive dendritic cells in the tumor immune microenvironment; this immunomodulatory effect, combined with PD-L1 silencing at protein levels, contributed to ~62% inhibition of tumor growth with no organ damage (confirmed by hematoxylin and eosin staining of major organs and normal biochemical indices). Conclusions CA/ZYII-siP-c-L integrates safety, targeting, and codelivery capabilities, offering a promising strategy for breast cancer treatment by combining siP-mediated immunity regulation and the antitumor effects of ZYII.

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