Glypican-3 Targeting of Liver Cancer Cells Using Multifunctional Nanoparticles

Abstract

Imaging is essential in accurately detecting, staging, and treating primary liver cancer (hepatocellular carcinoma [HCC]), one of the most prevalent and lethal malignancies. We developed a novel multifunctional nanoparticle (NP) specifically targeting glypican-3 (GPC3), a proteoglycan implicated in promotion of cell growth that is overexpressed in most HCCs. Quantitative real-time polymerase chain reaction was performed to confirm the differential GPC3 expression in two human HCC cells, Hep G2 (high) and HLF (negligible). These cells were treated with biotin-conjugated GPC3 monoclonal antibody (αGPC3) and subsequently targeted using superparamagnetic iron oxide NPs conjugated to streptavidin and Alexa Fluor 647. Flow cytometry demonstrated that only GPC3-expressing Hep G2 cells were specifically targeted using this αGPC3-NP conjugate (fourfold mean fluorescence over nontargeted NP), and magnetic resonance imaging (MRI) experiments showed similar findings (threefold R 2 relaxivity). Confocal fluorescence microscopy localized the αGPC3 NPs only to the cell surface of GPC3-expressing Hep G2 cells. Further characterization of this construct demonstrated a negatively charged, monodisperse, 50 nm NP, ideally suited for tumor targeting. This GPC3-specific NP system, with dual-modality imaging capability, may enhance pretreatment MRI, enable refined intraoperative HCC visualization by near-infrared fluorescence, and be potentially used as a carrier for delivery of tumor-targeted therapies, improving patient outcomes.