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Comparison of distribution and activity of nanoparticles with short interfering DNA (Dbait) in various living systems
N Berthault1, B Maury, C Agrario
1Département de Transfert, Institut Curie, Orsay, France.
Abstract:
Introducing small DNA molecules (Dbait) impairs the repair of damaged chromosomes and provides a new method for enhancing the efficiency of radiotherapy in radio-resistant tumors. The radiosensitizing activity is dependent upon the efficient delivery of Dbait molecules into the tumor cells. Different strategies have been compared, to improve this key step. We developed a pipeline of assays to select the most efficient nanoparticles and administration protocols before preclinical assays: (i) molecular analyses of complexes formed with Dbait molecules, (ii) cellular tests for Dbait uptake and activity, (iii) live zebrafish embryo confocal microscopy monitoring for in vivo distribution and biological activity of the nanoparticles and (iv) tumor growth and survival measurement on mice with xenografted tumors. Two classes of nanoparticles were compared, polycationic polymers with linear or branched polyethylenimine (PEI) and covalently attached cholesterol (coDbait). The most efficient Dbait transfection was observed with linear PEI complexes, in vitro and in vivo. Doses of coDbait ten-fold higher than PEI/Dbait nanoparticles, and pretreatment with chloroquine, were required to obtain the same antitumoral effect on xenografted melanoma. However, with a 22-fold lower 'efficacy dose/toxicity dose' ratio as compared with Dbait/PEI, coDbait was selected for clinical trials.
Insights
Small DNA molecules (Dbait) enhance radiotherapy for radio-resistant tumors by impairing DNA repair. Linear polyethylenimine (PEI) nanoparticles efficiently deliver Dbait, improving tumor treatment and paving the way for clinical trials.
Area of Science:
- Oncology
- Nanotechnology
- Radiotherapy
Background:
- Small DNA molecules (Dbait) show promise for enhancing radiotherapy efficacy in radio-resistant tumors.
- Dbait's radiosensitizing effect relies on efficient delivery into tumor cells.
- Optimizing nanoparticle delivery systems is crucial for therapeutic success.
Purpose of the Study:
- To develop and validate an assay pipeline for selecting optimal nanoparticles and administration protocols for Dbait delivery.
- To compare the efficiency of linear/branched polyethylenimine (PEI) and cholesterol-conjugated Dbait (coDbait) nanoparticles.
- To assess Dbait-loaded nanoparticle performance in vitro, in vivo using zebrafish, and in preclinical mouse xenograft models.
Main Methods:
- Evaluated Dbait-nanoparticle complex formation and molecular characteristics.
- Assessed Dbait cellular uptake and biological activity in vitro.
- Utilized live zebrafish embryo confocal microscopy for in vivo distribution and activity monitoring.
- Measured tumor growth inhibition and survival rates in mice bearing xenografted tumors.
Main Results:
- Linear PEI nanoparticles demonstrated superior Dbait transfection efficiency compared to branched PEI and coDbait, both in vitro and in vivo.
- Significantly higher doses of coDbait or chloroquine pretreatment were needed to achieve similar anti-tumoral effects as PEI/Dbait nanoparticles.
- PEI/Dbait nanoparticles exhibited a more favorable efficacy dose/toxicity dose ratio than coDbait.
Conclusions:
- Linear PEI nanoparticles represent a highly efficient system for delivering Dbait to enhance radiotherapy.
- The developed assay pipeline effectively identifies optimal nanoparticle delivery strategies.
- Dbait/PEI nanoparticles show significant potential for clinical translation in treating radio-resistant tumors.
