Escherichia coli Mimetic Gold Nanorod-Mediated Photo- and Immunotherapy for Treating Cancer and Its Metastasis

Most cancer-related deaths are due to metastasis or recurrence. Therefore, the ultimate goal of cancer therapy will be to treat metastatic and recurrent cancers. Combination therapy for cancer will be one of trial for effective treating metastasis and recurrence. In this study, Escherichia coli-mimetic nanomaterials are synthesized using Escherichia coli membrane proteins, adhesion proteins, and gold nanorods, which are named E. coli mimetic AuNRs (ECA), for combination therapy against cancer and its recurrence. ECA treatment with 808 nm laser irradiation eliminates CT-26 or 4T1 tumors via a photothermal effect. ECA with laser irradiation induces activation of immune cells in the tumor-draining lymph nodes. The mice cured from CT-26 or 4T1 tumor by ECA are rechallenged with those cancer in the lung metastatic form, and the results showed that ECA treatment for the first CT-26 or 4T1 tumor challenge prevents cancer infiltration to the lung in the second challenge. This preventive effect of ECA against tumor growth in the second challenge is aided by cancer antigen-specific T cell immunity. Overall, these findings show that ECA is a nanomaterial with dual functions as a photothermal therapy for treating primary cancers and as immunotherapy for preventing recurrence and metastasis.