fluorescence imaging of hepatocellular carcinoma using a novel GPC3-specific aptamer probe.

BACKGROUND

Glypican-3 (GPC3) is highly expressed in most of the hepatocellular carcinomas (HCCs), even in small HCCs. It may be used as a potential biomarker for early detection of HCC. The aptamer is a promising targeting agent with unique advantages over antibody. This study was to introduce a novel GPC3 specific aptamer (AP613-1), to verify its specific binding property , and to evaluate its targeting efficiency by performing near-infrared (NIR) fluorescence imaging on an HCC xenograft model.

METHODS

AP613-1 was generated from the systematic evolution of ligands by exponential enrichment. Flow cytometry and aptamer-based immunofluorescence imaging were performed to verify the binding affinity of AP613-1 to GPC3 . NIR Fluorescence images of nude mice with unilateral (n=12) and bilateral (n=4) subcutaneous xenograft tumors were obtained. Correlation between the tumor fluorescence intensities and was analyzed.

RESULTS

AP613-1 could specifically bind to GPC3 . and tumors, fluorescence intensities were in excellent correlation (P<0.001, r=0.968). The fluorescence intensity is significantly higher in tumors given Alexa Fluor 750 (AF750) labeled AP613-1 than in those given AF750 labeled initial ssDNA library both (P<0.001) and (P=0.022). In the mice with bilateral subcutaneous tumors injected with AF750 labeled AP613-1, Huh-7 tumors showed significantly higher fluorescence intensities than A549 tumors both (P=0.016) and (P=0.004).

CONCLUSIONS

AP613-1 displays a specific binding affinity to GPC3 positive HCC. Fluorescently labeled AP613-1 could be used as an imaging probe to subcutaneous HCC in xenograft models.