Dual receptor recognizing liposomes containing paclitaxel and hydroxychloroquine for primary and metastatic melanoma treatment via autophagy-dependent and independent pathways

Autophagy acts as a cytoprotective mechanism for malignant tumors, thus maintaining the survival and promoting proliferation and metastasis of malignant tumors. Recent studies have showed that autophagy inhibitors can enhance the chemotherapeutic efficacy of anti-tumor growth. However, the antimetastasis effects and the possible mechanisms of chemotherapeutics combined with autophagy inhibitors have not been thoroughly explored. Here, we prepared R8-dGR peptide modified paclitaxel (PTX) and hydroxychloroquine (HCQ) co-loaded liposomes (PTX/HCQ-R8-dGR-Lip) for enhanced delivery by recognizing integrin αvβ3 receptors and neuropilin-1 receptors on B16F10 melanoma cells. Our results showed that R8-dGR modified liposomes (R8-dGR-Lip) enhanced tumor-targeting delivery in vitro and in vivo. Besides, PTX/HCQ-R8-dGR-Lip exhibited the optimum inhibitory effects on migration, invasion and anoikis resistance of B16F10 cells in vitro, and showed enhanced efficiency on inhibiting primary tumor growth and reducing lung metastasis in vivo. Meanwhile, the antimetastasis mechanism studies confirmed that the combination of the chemotherapeutic PTX and the autophagy inhibitor HCQ further suppressed the degradation of paxillin, the expression of MMP9 and MMP2. Moreover, HCQ disturbed the CXCR4/CXCL12 axis which could induce invasion and metastasis of malignant melanoma in an autophagy-independent way.