BackgroundMelanoma is an aggressive cancer with poor response to traditional therapies. A combination of photothermal therapy and topical immunotherapy may enhance elimination of melanoma.. Materials and methodsC57BL/6 mice with early stage and metastatic melanoma were treated with laser immunotherapy (LIT), combining near-infrared laser-based photothermal therapy (PTT) and topical imiquimod (IMQ)-based immunotherapy. The volume of primary and abscopal melanoma, animal survival, tissue temperature, transcriptome, and immune cell response were investigated to evaluate the effect of LIT. ResultsLIT could eliminate primary tumors, inhibite abscopal tumors, and prolong animal survival. The tumor tissues were selectively destroyed under a photothermal gradient between 38.2 ± 3.7 °C and 73.0 ± 2.3 °C. Gene expression analysis showed a significant increase in the expression of damage associated molecular patterns. Additionally, the population of mature dendritic cells, CD4+ T cells, and CD8+ T cells were increased, while myeloid-derived suppressor cells were downregulated after LIT. ConclusionThe study showed that LIT inhibited the growth of both primary and abscopal melanoma by activating systemic antitumor immune responses and reversing the immunosuppressive tumor microenvironment, making LIT a potential method for advanced melanoma treatment.
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