Timosaponin AIII-based liposomes loaded with Auranofin for the induction of ferroptosis in anaplastic thyroid carcinoma

Purpose: Anaplastic thyroid carcinoma (ATC) is an exceptionally aggressive malignancy that, despite accounting for only 1%-1.5% of all thyroid cancers, is responsible for over half of thyroid cancer-related deaths. Characterized by limited treatment options and a poor prognosis, ATC presents a critical clinical challenge. In this study, we developed and evaluated an innovative liposomal system (T-AUF-LPs) co-loading Auranofin (AUF) and Timosaponin AIII (TAIII) aimed at inducing ferroptosis in ATC cells. Methods: T-AUF-LPs were prepared via the film-hydration method and their physicochemical properties were characterized. Cellular uptake, anti-proliferative effects, and ferroptosis-related mechanisms—including reactive oxygen species (ROS), iron levels, glutathione (GSH), GPX4, ACSL4, and NCOA4—were assessed in CAL-62 and 8505C ATC cell lines. In vivo antitumor efficacy and biosafety were evaluated using a BALB/c nude mouse xenograft model. Results: T-AUF-LPs showed superior physicochemical properties compared to conventional liposomes, including uniform spherical morphology, reduced particle size, and enhanced encapsulation efficiency. Cellular assays revealed significantly improved uptake of T-AUF-LPs in both ATC cell lines. The formulation inhibited cell proliferation in a dose-dependent manner, an effect effectively reversed by ferrostatin-1, confirming ferroptosis as the primary cell death mechanism. Mechanistic investigations indicated that T-AUF-LPs treatment increased intracellular ROS and iron levels, depleted GSH, and induced upregulation of ACSL4 and NCOA4 along with downregulation of GPX4. In vivo evaluation demonstrated effective tumor growth suppression with an excellent safety profile and no significant organ toxicity. Conclusion: T-AUF-LPs exert potent anti-tumor effects by inducing ferroptosis without causing systemic organ toxicity. They represent a promising therapeutic strategy for ATC, thereby addressing a critical unmet need in the management of this disease.