OR17

Enhancing anti-tumoral properties of specific extracellular vesicles via miRNA loading: A novel approach for gene therapy in breast and pancreatic cancer models

G TOSSOU(1,4) N Ourari(1,4) M Ralu(1,4) F Guaddachi(1,4) A Montanede(3) M Le Bras(1,4) J Lehmann-Che(1) S Jauliac(1,4)

1:INSERM UMR1342; 2:Assistancepublique-HôpitauxdeParis(AP-HP); 3:Inovarion; 4:Université Paris Cité

Extracellular vesicles (EVs) are tiny, membrane-enclosed structures released by cells, playing a key role in intercellular communication by transporting biomolecules such as nucleic acids, proteins, metabolites, and lipids. They can exert both paracrine and endocrine signaling, traveling through biological fluids with low immunogenic properties, making them promising vehicles for targeted delivery of therapeutic agents. Although EVs are often associated with pro-tumoral effects, our previous work demonstrated that EVs produced by cells expressing the anti-tumoral transcription factor NFAT3 can suppress tumor growth and metastatic dissemination in a breast cancer model. We identified 15 microRNAs (miRNAs) within these EVs responsible for their anti-tumoral and anti-metastatic functions, validated as either anti-proliferative, anti-invasive, or both. To enhance the anti-tumoral properties of EVs from NFAT3-expressing HEK293T cells, they were used to perform an exogeneous loading of the 15 miRNAs. Following validation of  the loading efficiency, we evaluated the impact on cancer cell proliferation using an in vitro 3D heterospheroid assay on two triple-negative breast cancer cell lines and a pancreatic cancer cell line. The results showed that exogenous loading of HEK293T EVs with the miRNAs enhances their anti-tumoral effect and that these EVs induce the maximum inhibition of growth across all cell lines, when compared to loaded ADSC EVs and liposomes. In vivo, only loaded HEK293T EVs demonstrated a significant tumor growth inhibition in athymic nude mice. These results provide proof of concept for miRNA-based therapies using EVs as delivery vehicles, laying the foundation for developing a potential gene therapy drug based on this approach.