Near-infrared fluorescence imaging and photodynamic therapy with indocyanine green lactosome has antineoplastic effects for hepatocellular carcinoma

BACKGROUND Anticancer agents and operating procedures have been developed for hepatocellular carcinoma (HCC) patients, but their prognosis remains poor. It is necessary to develop novel diagnostic and therapeutic strategies for HCC to improve its prognosis. Lactosome is a core-shell-type polymeric micelle, and enclosing labeling or anticancer agents into this micelle enables drug delivery. In this study, we investigated the diagnostic and therapeutic efficacies of indocyanine green (ICG)-loaded lactosome for near-infrared fluorescence (NIF) imaging and photodynamic therapy (PDT) for HCC. METHODS The human HCC cell line HuH-7 was treated with ICG or ICG-lactosome, followed by PDT, and the cell viabilities were measured (in vitro PDT efficiency). For NIF imaging, HuH-7 cells were subcutaneously transplanted into BALB/c nude mice, followed by intravenous administration of ICG or ICG-lactosome. The transplanted animals were treated with PDT, and the antineoplastic effects were analyzed (in vivo PDT efficiency). RESULTS PDT had toxic effects on HuH-7 cells treated with ICG-lactosome, but not ICG alone. NIF imaging revealed that the fluorescence of tumor areas in ICG-lactosome-treated animals was higher than that of contralateral regions at 24 h after injection and thereafter. PDT exerted immediate and continuous phototoxic effects in the transplanted mice treated with ICG-lactosome. CONCLUSIONS Our results demonstrate that ICG-lactosome accumulated in xenograft tumors, and that PDT had antineoplastic effects on these malignant implants. NIF imaging and PDT with ICG-lactosome could be useful diagnostic and/or therapeutic strategies for HCC.