Palmitoyl ascorbate and doxorubicin co-encapsulated liposome for synergistic anticancer therapy

Combination therapy with two drugs and nanoparticle-based drug delivery systems are widely applied to reduce the adverse effects of traditional treatment by chemotherapeutic drugs. Palmitoyl ascorbate (PA) as a lipophilic derivative of ascorbic acid shows the advantages in cancer treatment. The aim of the study was to prepare a doxorubicin (DOX) and PA co-loaded liposome to synergistically treat tumor and effectively alleviate the toxicity caused by DOX. The effects were evaluated by in vitro and in vivo studies. The liposomes (weight ratio of DOX to PA=1:20, DOX₁/PA₂₀-LPs) exhibited the strongest synergistic effects, combination index was 0.38, 0.56, and 0.05 in MCF-7, HepG2, and A549 cells, respectively. In vitro cellular uptake study, the intercellular concentration of DOX in DOX₁/PA₂₀-LPs was 2.5-fold greater than DOX loaded liposome, and DOX₁/PA₂₀-LPs was taken in not only by macropinocytosis, but also by clathrin-mediated endocytosis. Intracellular distribution experiment showed that DOX₁/PA₂₀-LPs efficiently concentrated in the nucleus. In vivo studies indicated that co-encapsulated liposome not only showed the strongest antitumor ability by tumor growth suppression, but also significantly enhanced the safety by the change of body weight and reduced damages to other tissues (evidenced by histopathology study). These results indicated that DOX and PA co-delivery liposome successfully enhanced the anticancer efficacy and mitigated the toxicities of DOX, which displayed potential for clinical application with enhanced safety and efficacy.