Development of human salivary gland cell lines for modeling radiation-induced damage in three-dimensional spheroid...

No permanent cure exists for salivary gland (SG) damage and consequent xerostomia (dry mouth) in patients undergoing radiotherapy for head and neck cancers. The lack of commercially available healthy human SG-derived cell lines has hindered in vitro studies of radiation-induced glandular injury. In this study, we successfully immortalized and characterized two novel human major SG-derived cell lines. Leveraging these cell lines and hyaluronic-acid hydrogels, we bioengineered distinct multicellular SG spheroids and microtissues expressing key acinar, ductal, myoepithelial, and mesenchymal cell markers in long-term cultures. Further, using this platform, we developed a proof-of-concept radiation injury model, demonstrating spheroid disruption characterized by actin depolymerization, DNA damage, apoptosis, and loss of SG-specific markers following radiation exposure. Notably, these detrimental effects were partially mitigated with a radioprotective agent. Our findings demonstrate that the bioengineered SG spheroids provide a scalable and versatile platform with significant potential for disease modeling and drug testing, thereby accelerating the development of targeted therapies for radiation-induced xerostomia.