Melanin-like nanoparticles decorated with an autophagy-inducing peptide for efficient targeted photothermal therapy.

Photothermal therapy efficiently ablates tumors via hyperthermia but inevitably induces serious side effects including thermal damage to normal tissues, inflammations and enhanced risk of tumor metastasis. In this study, we fabricated a dual peptide decorated melanin-like nanoparticle for tumor-targeted and autophagy-promoted photothermal therapy in pursuit of improved cancer treatment. The multifunctional nanoparticle was composed of dual peptide RGD- and beclin 1-modified and PEGylated melanin-like polydopamine nanoparticles. Beclin 1-derived peptide modified on the nanoparticle up-regulated autophagy in cancer cells and further sensitized the tumors to photothermal ablation. RGD decorated on the particle surface enhanced the selectivity and cellular uptake of polydopamine nanoparticles by breast cancer cells. In vivo therapeutic experiments revealed that the tumor-targeted and autophagy promotion-associated photothermal therapy efficiently regressed tumors at a low temperature around 43 °C. The study provides a novel and efficient strategy to improve the efficiency of photothermal therapy via the up-regulation of autophagy in tumor cells.