Photo-activated chemo-immunotherapy for metastatic cancer using a synergistic graphene nanosystem

We developed a novel treatment strategy for metastatic cancer by synergizing photothermal therapy (PTT), chemotherapy, and immunotherapy through a nanosystem to trigger host antitumor immunity. The nanosystem was constructed by loading mitoxantrone (MTX), a chemotherapeutic agent, and SB-431542 (SB), a transforming growth factor beta (TGF-beta) inhibitor, onto reduced graphene oxide (rGO). Intratumoral administration of rGO/MTX/SB, followed by non-invasive irradiation of a near-infrared laser, destroyed local primary tumors and inhibited distant metastases in 4T1 mouse mammary tumor model, which is poorly immunogenic and highly metastatic. After treatment, 70% of the tumor-bearing mice became long-term survivors and developed a tumor type-specific immunity to resist rechallenged tumor cells. We found that rGO-based PTT provided an immunogenic antigen source, forming in situ vaccination with rGO as an immune-adjuvant. The use of SB changed the tumor microenvironment and improved the therapeutic effect of MTX-generated chemotherapy and rGO-based PTT. The immunological functions of MTX, SB, and rGO acted synergistically to induce an effective tumor vaccination, as evidenced by the increased infiltration of tumor-specific cytotoxic CD8(+) T lymphocytes and decreased infiltration of regulatory T cells (Tregs) in distal tumors. Collectively, we demonstrated that rGO/ MTX/SB combined with laser irradiation provided a synergistic chemo-immuno-photothermal effect against tumors by in situ vaccination and inhibition of immunosuppressive microenvironment. This unique combination embodies a promising approach to treat metastatic cancers by inducing a systemic antitumor response through a local intervention.

Automated summary

By combining photothermal therapy, chemotherapy, and immunotherapy through a nanosystem, researchers developed a treatment strategy that not only destroyed local tumors and inhibited distant metastases in mouse models but also induced long-term survivors with tumor type-specific immunity. This synergistic approach showed potential for treating metastatic cancers by inducing a systemic antitumor response through a local intervention.