Effect of Cetuximab-Conjugated Gold Nanoparticles on the Cytotoxicity and Phenotypic Evolution of Colorectal Cancer Cells

Abstract

Epidermal growth factor receptor (EGFR) is estimated to be overexpressed in 60~80% of colorectal cancer (CRC), which is associated with a poor prognosis. Anti-EGFR targeted monoclonal antibodies (cetuximab and panitumumab) have played an important role in the treatment of metastatic CRC. However, the therapeutic response of anti-EGFR monoclonal antibodies is limited due to multiple resistance mechanisms. With the discovery of new functions for gold nanoparticles (AuNPs), we hypothesize that cetuximab-conjugated AuNPs (cetuximab-AuNPs) will not only improve the cytotoxicity for cancer cells, but also introduce expression change of the related biomarkers on cancer cell surface. In this contribution, we investigated the size-dependent cytotoxicity of cetuximab-AuNPs to CRC cell line (HT-29), while also monitored the expression of cell surface biomarkers in response to treatment with cetuximab and cetuximab-AuNPs. AuNPs with the size of 60 nm showed the highest impact for cell cytotoxicity, which was tested by cell counting kit-8 (CCK-8) assay. Three cell surface biomarkers including epithelial cell adhesion molecule (EpCAM), melanoma cell adhesion molecule (MCAM), and human epidermal growth factor receptor-3 (HER-3) were found to be expressed at higher heterogeneity when cetuximab was conjugated to AuNPs. Both surface-enhanced Raman scattering/spectroscopy (SERS) and flow cytometry demonstrated the correlation of cell surface biomarkers in response to the drug treatment. We thus believe this study provides powerful potential for drug-conjugated AuNPs to enhance cancer prognosis and therapy.

SERS characterization of colorectal cancer cell surface markers upon anti‐EGFR treatment

“…Our previous study has demonstrated that higher SERS activity could be obtained by using AuNPs (60 nm) as compared to smaller AuNPs (i.e., 25 and 40 nm). [ 23 ] Meanwhile, 60 nm AuNPs are less prone to aggregation compared to larger AuNPs at size of 80 nm. [ 23 ] Thus, AuNPs (60 nm) were used in this study.…”

“…[ 23 ] Meanwhile, 60 nm AuNPs are less prone to aggregation compared to larger AuNPs at size of 80 nm. [ 23 ] Thus, AuNPs (60 nm) were used in this study. The size and morphology of AuNPs were investigated with transmission electron microscopy (TEM), where the quasi‐spherical shape of as‐prepared AuNPs was observed (Figure 2A).…”

“…TEM images (A), normalized UV-vis spectra (B) and SERS spectra (C) of AuNPs before and after coating with Raman molecule (Ra, DTNB)) and anti-EGFR antibody anti-EGFR antibody (isoelectric point 8.5), which was positively charged in PBS of pH 7.4. [23,24] The Raman spectrum of a typical SERS nanotag (coated by DTNB and Ab) displayed distinct signal enhancement effect for DTNB (Figure 2C), which is attributed to the electromagnetic effect induced by localized surface plasmon resonance. [21a,25]…”

Antibody‐Incorporated Nanomedicines for Cancer Therapy

“…Moreover, enhanced therapeutic efficacy of cetuximab-functionalized nanoaprticles has been reported in different nanomedicine systems. [455][456][457][458][459][460] For example, Landgraf et al constructed porous silicon nanoparticles modified by chemotherapeutic drug camptothecin (CPT) and anti-EGFR cetuximab for cancer-targeted delivery. [458] CPT-loaded porous silicon nanoparticles bearing active targeting capacity contributed to the inhibition of orthotopic primary tumor growth, an increase in survival rate, and notable reduction in humanized tissue-engineered bone constructs and murine liver, lung, and bone metastases.…”

Nanocarriers as a Tool for the Treatment of Colorectal Cancer

“…Results showed the cytotoxicity of cetuximab-AuNPs to cancer cells, with NPs mainly possessing a size of 60 nm. It was also possible to analyze the change in the expression of biomarkers on the surface of the cancer cell, where, after treatment with cetuximab-AuNPs, there was a greater expression of epithelial cell markers: epithelial cell adhesion molecule (EpCAM), melanoma cell adhesion molecule (MCAM) and human epidermal growth factor receptor-3 [ 107 ].…”