Liposome-mediated co-delivery of enzalutamide and PMEPA1 overexpression plasmid suppresses prostate cancer progression by targeting the androgen receptor signaling pathway

Castration-resistant prostate cancer (CRPC) remains a major therapeutic challenge, largely due to persistent androgen receptor (AR) and AR splice variant 7 (AR-V7) signaling that drive resistance to agents such as enzalutamide (Enz). Here, we report a liposomal nanocarrier based on DSPE-PEG2000-DCL (Lipo-Enz/PMEPA1) for the co-delivery of Enz and a PMEPA1 overexpression plasmid to overcome drug resistance. We first demonstrate that PMEPA1 is significantly downregulated in metastatic CRPC compared to primary prostate tumors and normal tissues, based on TCGA and SU2C/PCF Dream Team datasets, and that low PMEPA1 expression correlates with poor overall survival. Immunohistochemical analysis from the Human Protein Atlas further confirms reduced PMEPA1 protein levels in CRPC. In vitro, Lipo-Enz/PMEPA1 exhibits excellent stability and efficiently delivers both payloads into LNCaP and 22Rv1 cells. Combination treatment synergistically inhibits cell proliferation, migration, and invasion, while promoting apoptosis. Mechanistically, PMEPA1 binds to AR and promotes its downregulation, leading to suppression of both full-length AR and AR-V7 signaling. AR knockdown abolishes the anti-tumor effects of PMEPA1 overexpression, confirming pathway dependence. Furthermore, in vivo studies using a 22RV1 xenograft mouse model demonstrated that Lipo-Enz/PMEPA1 significantly suppressed tumor growth compared to free Enz or control treatments. Histopathological analysis revealed that while free Enz caused significant liver damage, the liposomal formulation markedly reduced hepatotoxicity. Thus, liposome-mediated co-delivery of Enz and PMEPA1-OE represents a promising strategy to simultaneously target AR and AR-V7 and overcome Enz resistance in CRPC.