Anti-Trop2-Guided Liposomes Restore Methotrexate Sensitivity in Chemoresistant Gestational Trophoblastic Neoplasia.

PURPOSE: Methotrexate (MTX) resistance limits its clinical efficacy in gestational trophoblastic neoplasia (GTN). To develop safer treatment strategies for patients of reproductive age, this study aims to investigate whether anti-trophoblast cell surface antigen 2 (Anti-Trop2) facilitates the tumor-targeted delivery of MTX-loaded liposomes, thereby enhancing drug sensitivity in chemoresistant GTN. METHODS: Clinical samples were collected to detect trophoblast cell surface antigen 2 (Trop2) in MTX-resistant GTN. A methotrexate-loaded targeted liposome (A-Lipo@MTX) was designed and fully characterized. In vitro experiments were performed to evaluate the cellular uptake efficiency and cytotoxicity of the liposomes in MTX-resistant JEG3 cells (JEG3R), and to explore the underlying mechanism. The antitumor efficacy against drug-resistant tumors and initial biosafety of A-Lipo@MTX were further assessed in animal models. RESULTS: Clinical specimens revealed that Trop2 was significantly upregulated in chemoresistant GTN tissues. Trop2 could serve as a potential therapeutic target for drug-resistant tumors. The designed A-Lipo@MTX exhibited a uniform nanoscale size (~210 nm), high encapsulation efficiency (~85%), and favorable stability. In vitro, Anti-Trop2 functionalization significantly increased liposomal endocytosis within MTX-resistant GTN cells; the resulting intracellular MTX accumulation inhibited PI3K-AKT-mTOR signaling and triggered tumor cell apoptosis. In vivo imaging results confirmed its increased tumor accumulation, which translated into superior antitumor efficacy. Importantly, A-Lipo@MTX improved biosafety during medication, as indicated by stable body weight, normal serum biochemical parameters, and minimal organ damage. CONCLUSION: This study identifies Trop2 as an effective target to promote liposome specific uptake, elevates intratumoral MTX accumulation at tumor sites, and suppress the activation of drug-resistant signaling pathways. This strategy provides a clinically relevant and safer approach for overcoming chemoresistance in GTN.