Epidermal growth factor receptor (EGFR), a cellular transmembrane receptor, plays a key role in cell proliferation and is linked to a poor prognosis in various human cancers. In this study, we constructed Cetuximab-immunomicelles in which the anti-EGFR monoclonal antibody was linked to poly(ethylene glycol)-block-poly(ɛ-caprolactone) (PEG-PCL) nanomicelles that were loaded with doxorubicin (DOX) and superparamagnetic iron oxide (SPIO). The specific interactions between EGFR-overexpressing tumor cells (A431) and immunomicelles were observed using confocal laser scanning microscopy (CLSM) and flow cytometry. Furthermore, the capacity of transporting SPIO into tumor cells using these immunomicelles was evaluated with a 1.5 T clinical magnetic resonance imaging (MRI) scanner. It was found that the acquired MRI T2 signal intensity of A431 cells that were treated with the SPIO-loaded and antibody-functionalized micelles decreased significantly. Using the thiazolyl blue tetrazolium bromide (MTT) assay, we also demonstrated that the immunomicelles inhibited cell proliferation more effectively than their nontargeting counterparts. Our results suggest that Cetuximab-immunomicelles are a useful delivery vehicle for DOX and SPIO to EGFR-overexpressing tumor cells in vitro and that Cetuximab-immunomicelles can serve as a MRI-visible and targeted drug delivery agent for better tumor imaging and therapy.
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