Elsevier

Neoplasia

Volume 9, Issue 12, December 2007, Pages 1099-1110
Neoplasia

Internalization, Intracellular Trafficking, Biodistribution of Monoclonal Antibody 806: A Novel Anti-Epidermal Growth Factor Receptor Antibody1,2

https://doi.org/10.1593/neo.07721Get rights and content
Under a Creative Commons license
open access

Abstract

Overexpression of the epidermal growth factor receptor (EGFR) in epithelial tumors is associated with poor prognosis and is the target for a number of cancer therapeutics. Monoclonal antibody (mAb) 806 is a novel anti-EGFR antibody with significant therapeutic efficacy in tumor models when used as a single agent, displays synergistic antitumor activity in combination with other EGFR therapeutics. Unlike other EGFR antibodies, mAb 806 is selective for tumor cells and does not bind to normal tissue, making it an ideal candidate for generation of radioisotope or toxin conjugates. Ideally, antibodies suited to these therapeutic applications must bind to and actively internalize their cognate receptor. We investigated the intracellular trafficking of fluorescently tagged mAb 806 in live cells and analyzed its biodistribution in a tumor xenograffed nude mouse model. Following binding to EGFR, mAb 806 was internalized through dynamin-dependent, clathrin-mediated endocytosis. Internalized mAb 806 localized to early endosomes and subsequently trafficked to and accumulation in lysosomal compartments. Furthermore, biodistribution analysis in nude mice showed specific uptake and retention of radiolabeled mAb 806 to human tumor xenografts. These results highlight the potential use of mAb 806 for generation of conjugates suitable for diagnostic and therapeutic use in patients with EGFR-positive malignancies.

Keywords

Internalization
epidermal growth factor receptor
intracellular trafficking
dynamin
monoclonal antibody

Abbreviations

Cy3
cyanine 3
EEA1
early endosome autoantigen 1
EGFR
epidermal growth factor receptor
FITC
fluorescein isothiocyanate
GFP
green fluorescent protein
LAMP1
lysosomal-associated membrane protein 1
mAb
monoclonal antibody
PFA
paraformaldehyde
Tfn
transferrin

Cited by (0)

1

This work was partly supported by the National Health and Medical Research Council of Australia (Program Grant 280912), the Human Frontier Science Program (Young Investigator Award RGY40/2003), Bayer Pharmaceuticals Scholar Award, the Ludwig Institute for Cancer Research (to D.T), a Boehringer Ingelheim Fonds PhD Scholarship (to R.Z.).

2

This article refers to supplementary materials, which are designated by Figure W1 and Videos W1 to W5 and are available online at www.neoplasia.com.

3

Current address: Department of Cell Biology, Yale University School of Medicine, SHM C229, 333 Cedar Street, New Haven, CT 06520, USA.