Autophagy-Targeted Calcium Phosphate Nanoparticles Enable Transarterial Chemoembolization for Enhanced Cancer Therapy

Transarterial chemoembolization (TACE) is commonly used for treating advanced hepatocellular carcinoma (HCC). However, the instability of lipiodol-drug emulsion and the altered tumor microenvironment (TME, such as hypoxia-induced autophagy) postembolization are responsible for the unsatisfactory therapeutic outcomes. Herein, pH-responsive poly(acrylic acid)/calcium phosphate nanoparticles (PAA/CaP NPs) were synthesized and used as the carrier of epirubicin (EPI) to enhance the efficacy of TACE therapy through autophagy inhibition. PAA/CaP NPs have a high loading capacity of EPI and a sensitive drug release behavior under acidic conditions. Moreover, PAA/CaP NPs block autophagy through the dramatic increase of intracellular Ca²⁺ content, which synergistically enhances the toxicity of EPI. TACE with EPI-loaded PAA/CaP NPs dispersed in lipiodol shows an obvious enhanced therapeutic outcome compared to the treatment with EPI-lipiodol emulsion in an orthotopic rabbit liver cancer model. This study not only develops a new delivery system for TACE but also provides a promising strategy targeting autophagy inhibition to improve the therapeutic effect of TACE for the HCC treatment.