Development and evaluation of an inhalable nanoemulsion system for enhancing NK cell function against osteosarcoma
Sookyung Hwang1, Paul D Bates2, Vasiliki Valkanioti1
1Division of Pharmaceutical Sciences, University of Wisconsin School of Pharmacy, Madison, WI, United States.
Introduction:
Osteosarcoma frequently metastasizes to the lungs, significantly reducing survival in pediatric and young adult patients, with current therapies having limited efficacy. This study aimed to develop an inhalable nanoemulsion formulation to enhance targeted pulmonary drug delivery and restore natural killer (NK) cell-mediated immunity against metastatic osteosarcoma.
Methods:
A nanoemulsion composed of medium-chain triglyceride (MCT) oil and Distearoyl-rac-glycerol-PEG2000 (DSG-PEG2000), yielding droplets consistently smaller than 200 nm, was designed with demonstrated stability (>550 days), biocompatibility, mucus penetration ability, minimal toxicity on respiratory epithelium, and efficient cellular uptake. To enhance NK cell function in the osteosarcoma tumor microenvironment, the nanoemulsion was loaded with SIS3, a SMAD3 inhibitor targeting immunosuppressive TGF-β signaling, and conjugated with a cysteine-modified form of the NK-cell killer immunoglobulin-like receptor (KIR) antagonist nonamer peptide VAPWNSDAL (VAP-DAC) to block inhibitory LILRB1/ILT-2 on NK-92 cells.
Results:
The resulting SIS3-VAP-DAC nanoemulsion maintained particle sizes below 162 nm, stability over one month, enhanced cytotoxicity of human NK-92 cells, and restoration of granzyme B secretion despite TGF-β suppression, as well as induced NKG2D ligand expression on murine osteosarcoma cells. Intranasal administration of the SIS3-VAP-DAC nanoemulsion effectively reduced pulmonary tumor burden in human osteosarcoma xenograft mouse models with no observable clinical toxicity.
Discussion:
This study establishes a novel inhalable nanoemulsion platform that significantly restores NK-cell functionality against pulmonary metastatic osteosarcoma.
Insights
This study developed an inhalable nanoemulsion to deliver drugs directly to the lungs, enhancing natural killer (NK) cell immunity against metastatic osteosarcoma. The formulation effectively reduced lung tumors in mice, offering a promising new therapy.
Area of Science:
- Biomedical Engineering
- Nanotechnology
- Immunology
Background:
- Osteosarcoma lung metastasis significantly reduces survival in young patients.
- Current therapies for metastatic osteosarcoma have limited efficacy.
- Targeted pulmonary drug delivery is needed to enhance treatment outcomes.
Purpose of the Study:
- To develop an inhalable nanoemulsion for targeted pulmonary drug delivery.
- To restore natural killer (NK) cell-mediated immunity against metastatic osteosarcoma.
- To improve therapeutic efficacy for osteosarcoma lung metastases.
Main Methods:
- Developed a stable nanoemulsion (<200 nm) using MCT oil and DSG-PEG2000.
- Loaded nanoemulsion with SIS3 (SMAD3 inhibitor) and conjugated with VAP-DAC peptide to enhance NK cell function.
- Administered nanoemulsion via intranasal instillation in osteosarcoma xenograft mouse models.
Main Results:
- The SIS3-VAP-DAC nanoemulsion showed stability, enhanced NK-92 cell cytotoxicity, and restored granzyme B secretion.
- Nanoemulsion induced NKG2D ligand expression on osteosarcoma cells.
- Intranasal administration significantly reduced pulmonary tumor burden with no observable toxicity.
Conclusions:
- Established a novel inhalable nanoemulsion platform for treating pulmonary metastatic osteosarcoma.
- The nanoemulsion effectively restores NK-cell functionality in the tumor microenvironment.
- This approach offers a promising strategy to combat osteosarcoma lung metastases.
