Photosensitizer‐Free Phototherapy with Peptide Micelle Nanoadjuvants for Cancer Vaccine against Metastasis of Melanoma

Abstract

AbstractHere, an external photosensitizer‐free vaccination strategy accompanied by delivery of nanoadjuvants is reported as a treatment for melanoma. Melanin‐enriched B16F10 melanoma cells showed a strong and specific photothermal effect under irradiation of near‐infrared (NIR) wavelength light, and a corresponding killing effect of cancer cells is observed. The irradiated melanoma cells exhibited surface exposure of the eat‐me signal, calreticulin, which induced immunogenic cell death. The nanoadjuvant, which comprised imiquimod encapsulated in amphiphilic peptide‐based micelles, induced dendritic cell maturation. In B16F10 melanoma tumor‐bearing mice, irradiation of NIR light alone increased the temperature of the tumor site to 60 °C regardless of nanoadjuvant treatment. To mimic metastasis to sites near the primary tumor site, primary tumor‐cured mice are rechallenged with B16F10 cells. In a lung metastasis model induced by intravenous injection of B16F10 cells, only nanoadjuvant‐treated group showed significant prevention of B16F10 tumor nodule formation in the lung. The immunotherapeutic effects of this nanoadjuvant are supported by an observed increase of tumor‐infiltrating CD8 + T cell populations. The results suggest that the combination of photosensitizer‐free phototherapy with a peptide micelle nanoadjuvant has strong potential for clinical translation as a melanoma vaccine.