Defining Endocytic Pathways of Fucoidan-Coated PIBCA Nanoparticles from the Design of their Surface Architecture

The Internalization Pathways of Liposomes, PLGA, and Magnetic Nanoparticles in Neutrophils

BACKGROUND/OBJECTIVES

Neutrophils are emerging as promising candidates for cell-based nanodrug delivery to tumors due to their unique biological properties. This study aims to investigate the mechanisms of nanoparticle internalization by neutrophils, specifically focusing on liposomes, poly(lactic-co-glycolic acid) (PLGA), and magnetite nanoparticles. Understanding these mechanisms could enhance the efficiency of neutrophil-based nanodrug delivery for cancer treatment.

METHODS

Neutrophils were isolated from the peripheral blood of mice bearing 4T1 mammary adenocarcinoma. Confocal microscopy, transmission electron microscopy, and flow cytometry were employed to evaluate the uptake of liposomes, PLGA, and magnetite nanoparticles by neutrophils. The effects of cultivation conditions, such as the presence or absence of plasma in the growth medium, were also examined. Additionally, the roles of immunoglobulins (IgG/IgM) and cell surface receptors (Fc and scavenger receptors) in nanoparticle internalization were explored.

RESULTS

All types of nanoparticles were successfully internalized by neutrophils, though the mechanisms of uptake varied. Plasma presence in the medium significantly influenced nanoparticle binding, particularly for PLGA nanoparticles. Internalization of PLGA nanoparticles was found to depend on the presence of IgG/IgM in the medium and Fc receptors on neutrophil surfaces, while scavenger receptors were not involved.

CONCLUSIONS

Understanding the distinct endocytosis pathways for different nanoparticles can improve the efficacy of neutrophil loading with nanodrugs, potentially advancing the development of neutrophil-based cancer therapies. The findings underscore the importance of the extracellular environment in modulating nanoparticle uptake.

Active targeting tumor therapy using host-guest drug delivery system based on biotin functionalized azocalix[4]arene

Host-guest drug delivery systems (HGDDSs) provided a facile method for incorporating biomedical functions, including efficient drug-loading, passive targeting, and controlled drug release. However, developing HGDDSs with active targeting is hindered by the difficult functionalization of popular macrocycles. Herein, we report an active targeting HGDDS based on biotin-modified sulfonated azocalix[4]arene (Biotin-SAC4A) to efficiently deliver drug into cancer cells for improving anti-tumor effect. Biotin-SAC4A was synthesized by amide condensation and azo coupling. Biotin-SAC4A demonstrated hypoxia responsive targeting and active targeting through azo and biotin groups, respectively. DOX@Biotin-SAC4A, which was prepared by loading doxorubicin (DOX) in Biotin-SAC4A, was evaluated for tumor targeting and therapy in vitro and in vivo. DOX@Biotin-SAC4A formulation effectively killed cancer cells in vitro and more efficiently delivered DOX to the lesion than the similar formulation without active targeting. Therefore, DOX@Biotin-SAC4A significantly improved the in vivo anti-tumor effect of free DOX. The facilely prepared Biotin-SAC4A offers strong DOX complexation, active targeting, and hypoxia-triggered release, providing a favorable host for effective breast cancer chemotherapy in HGDDSs. Moreover, Biotin-SAC4A also has potential to deliver agents for other therapeutic modalities and diseases.

Nanotubes from bacteriophage tail sheath proteins: internalisation by cancer cells and macrophages

Bionanoparticles comprised of naturally occurring monomers are gaining interest in the development of novel drug transportation systems. Here we report on the stabilisation, cellular uptake, and macrophage clearance of nanotubes formed from the self-assembling gp053 tail sheath protein of the vB_EcoM_FV3 bacteriophage. To evaluate the potential of the bacteriophage protein-based nanotubes as therapeutic nanocarriers, we investigated their internalisation into colorectal cancer cell lines and professional macrophages that may hinder therapeutic applications by clearing nanotube carriers. We fused the bacteriophage protein with a SNAP-tag self-labelling enzyme and demonstrated that its activity is retained in assembled nanotubes, indicating that such carriers can be applied to deliver therapeutic biomolecules. Under physiological conditions, the stabilisation of the nanotubes by PEGylation was required to prevent aggregation and yield a stable solution with uniform nano-sized structures. Colorectal carcinoma cells from primary and metastatic tumours internalized SNAP-tag-carrying nanotubes with different efficiencies. The nanotubes entered HCT116 cells via dynamin-dependent and SW480 cells - via dynamin- and clathrin-dependent pathways and were accumulated in lysosomes. Meanwhile, peritoneal macrophages phagocytosed the nanotubes in a highly efficient manner through actin-dependent mechanisms. Macrophage clearance of nanotubes was enhanced by inflammatory activation but was dampened in macrophages isolated from aged animals. Altogether, our results demonstrate that gp053 nanotubes retained the cargo's enzymatic activity post-assembly and had the capacity to enter cancer cells. Furthermore, we emphasise the importance of evaluating the nanocarrier clearance by immune cells under conditions mimicking a cancerous environment.

NOAEL cancer therapy: a tumor targetable docetaxel-inorganic polymer nanohybrid prevents drug-induced neutropenia

To date, cancer therapies largely consist of five pillars: surgery, radiation, chemotherapy, targeted therapy, and immunotherapy. Still, researchers are trying to innovate the current cancer therapies to pursue an ideal one without side effects. For developing such a therapy, we designed a chemically well-defined route to a PEG- and docetaxel (DTX)-conjugated inorganic polymer, polyphosphazene, named "polytaxel (PTX)" with a prolonged blood circulation time and tumor localization. Here, we conducted the proof-of-concept study of the ideal therapy in orthotopic and xenograft pancreatic cancer models. We found that the average tumor inhibition rates of PTX were similar to those of DTX without any DTX toxicity-related side effects, such as neutropenia and weight loss. In conclusion, PTX met the requirements of an ideal anticancer drug with high anticancer efficacy and 100% survival rate. PTX is expected to replace any existing anticancer therapies in clinical practice.