Enhanced cytotoxic activity of cetuximab in EGFR-positive lung cancer by conjugating with gold nanoparticles.

Cetuximab (C225) is a unique agent, targeting epidermal growth factor receptor (EGFR)-positive cancer. However, the therapeutic effect of C225 in EGFR high-expressing non-small cell lung cancer (NSCLC) remains poor. Here, we report that conjugation of C225 with gold nanoparticles (AuNPs) enhances the cytotoxicity of C225 in NSCLC both in vitro and in vivo. The NSCLC cell lines A549 (EGFR(high)) and H1299 (EGFR(low)) were employed to investigate different responses to C225, IgG-AuNPs and C225-AuNPs. The antitumor properties of C225-AuNPs were explored in vivo by establishing a tumor xenograft model in nude mice. Overall, the therapeutic effect of C225-AuNPs was more pronounced in EGFR(high) A549 cells compared with EGFR(low) H1299 cells. The cytotoxic effect of C225-AuNPs in A549 cells increased in a dose-dependent manner. C225-AuNPs significantly suppressed A549 cell proliferation and migration capacity and accelerated apoptosis compared with C225, and this effect was probably due to enhanced EGFR endocytosis and the subsequent suppression of downstream signaling pathway. Finally in the tumor xenograft of nude mice, treatment with C225-AuNPs also led to a significant reduction in tumor weight and volume with low toxicity. Our findings suggest that C225-AuNPs conjugate has promising potential for targeted therapy of EGFR positive NSCLC patients.