Combined immunochemotherapy achieving targeted co-delivery of chlorogenic acid and doxorubicin by sialic acid-modified liposomes enhances anti-cancer efficacy.

Malignant melanoma is a high-grade aggressive skin tumor with an increasing incidence and mortality rates worldwide. Chemotherapeutic drugs such as doxorubicin have limited efficacy against melanoma due to their poor sensitivity, severe side effects, and drug resistance. Recent studies have shown that combinations of immunotherapy and chemotherapy have a synergistic effect in enhancing the anti-tumor effect. Here, we have developed liposomes co-loaded with chlorogenic acid (CA) and doxorubicin (DOX), modified with sialic acid-octadecylamine conjugate (SA-ODA), designated CA-DOX-SAL, that facilitate drug delivery by recognizing Siglec-1 receptor on TAMs. The physicochemical studies revealed the particle size and zeta potential of CA-DOX-SAL as 128.3 ± 0.8 nm and - 4.33 ± 0.50 mV, respectively. In vitro, CA-DOX-SAL demonstrated robust cellular uptake through SA receptor-mediated tumor-associated macrophages (TAM) targeting and exerted greater cytotoxicity on tumor cells. In vivo, targeted liposomes were found to accumulate in the tumor area, leading to an improvement in anti-tumor efficacy. In addition, CA-DOX-SAL effectively inhibited B16F10 melanoma tumor growth by stimulating the transition from tumor-promoting M2-type to anti-tumor M1-type and directly killing tumor cells. Overall, the co-delivery of immunomodulatory CA and chemotherapeutic DOX presents a promising therapeutic strategy to enhance clinical outcomes in the treatment of melanoma.