Anti-tumor response induced by immunologically modified carbon nanotubes and laser irradiation using rat mammary tumor model

The ideal treatment modality for metastatic cancer would be a local treatment that can destroy primary tumors while inducing an effective systemic anti-tumor response. To this end, we developed laser immunotherapy, combining photothermal laser application with an immunoadjuvant for the treatment of metastatic cancer. Additionally, to enhance the selective photothermal effect, we integrated light-absorbing nanomaterials into this innovative treatment. Specifically, we developed an immunologically modified carbon nanotube combining single-walled carbon nanotubes (SWNTs) with the immunoadjuvant glycated chitosan (GC). To determine the effectiveness of laser irradiation, a series of experiments were performed using two different irradiation durations - 5 and 10 min. Rats were inoculated with DMBA-4 cancer cells, a metastatic cancer cell line. The treatment group of rats receiving laser irradiation for 10 min had a 50% long-term survival rate without residual primary or metastatic tumors. The treatment group of rats receiving laser irradiation for 5 min had no long-term survivors; all rats died with multiple metastases at several distant sites. Therefore, Laser+SWNT-GC treatment with 10 min of laser irradiation proved to be effective at reducing tumor size and inducing long-term anti-tumor immunity.