Near-infrared phototherapy for patient-derived orthotopic xenograft model of hepatocellular carcinoma in combination with indocyanine green.

BACKGROUND Hepatocellular carcinoma notably takes up and retains indocyanine green (ICG). Here, we investigated whether patient-derived orthotopic xenograft of hepatocellular carcinoma could accumulate ICG and show full remission via phototherapy. METHODS NIR light and ICG were tested for cytotoxicity in cancerous cell lines (Huh-7, Hep3B). Patient-derived orthotopic xenograft (PDoX) mice were subjected to phototherapy comprising of daily NIR exposure (0.5-1.75 W/cm2) and intravenous injection of ICG (5-20 mg/kg2). Moreover, NIR laser was flashed on individual mouse until hepatocellular carcinoma completely loss the fluorescence, as determined by NIR camera. RESULTS Cytotoxicity increased in response to the input energy, but insufficient energy (< 150 joule/cm2) was irresponsive at all irradiances. NIR irradiance in the range of 0.5-1.75 W/cm2 took 5-7 days to elicit complete remission from PDoX mice in combination with 20 mg/kg ICG. In contrast, phototherapy could completely ablate hepatocellular carcinoma at 5-15 mg/kg ICG. CONCLUSIONS ICG could potentiate the tumoricidal ability of NIR light in a dose-dependent manner, and vice versa. Regardless of ICG dosage, however, phototherapy treated group showed a relatively high survival rate compared to the non-treated group. Notably, real-time phototherapy could halve the effective ICG dosage for full remission of deep-seated tumor.