Correlating EGFR expression with receptor-binding properties and internalization of 64Cu-DOTA-cetuximab in 5 cervical cancer cell lines.

Abstract

UNLABELLED:

The anti-epidermal growth factor receptor (anti-EGFR) antibody cetuximab is clinically approved for the treatment of EGFR-expressing metastatic colorectal cancer and advanced head and neck cancer. Overexpression of EGFR has also been found in more than 70% of carcinomas of the cervix. The overall goal of this study was to determine whether (64)Cu-1,4,7,10-tetraazacyclododecane-N,N',N'',N'''-tetraacetic acid (DOTA)-cetuximab has potential as an agent for measuring EGFR concentration by PET imaging in cervical cancer tumors.

METHODS:

Cetuximab was conjugated to the bifunctional chelator DOTA and labeled with (64)Cu. EGFR messenger RNA (mRNA) expression was correlated with EGFR densities on the cell surface of 5 different cervical cancer cell lines and with receptor function, measured by internalization of (64)Cu-DOTA-cetuximab. Imaging in tumor-bearing mice with small-animal PET was performed using the highest-expressing cervical cancer cell line.

RESULTS:

The affinity of (64)Cu-DOTA-cetuximab binding for the EGFR was similar in 4 EGFR-positive lines, varying from 0.1 to 0.7 nM. The mRNA expression corresponded well with EGFR densities and levels of internalization, with responses decreasing in the order of CaSki>ME-180>DoTc2 4510>HeLa>C-33A. Biodistribution and small-animal PET studies with (64)Cu-DOTA-cetuximab in CaSki tumor-bearing nude mice showed relatively high tumor uptake at 24 h after injection (13.2+/-1.2 percentage of injected activity per gram), although there was also significant retention of activity in the blood and liver accumulation.

CONCLUSION:

(64)Cu-DOTA-cetuximab was successfully used to detect and quantify EGFR expression in cervical cancer tumors, and small-animal PET/CT of EGFR-expressing CaSki tumors suggests potential for PET/CT of EGFR-positive tumors.

• Authors: Martin Eiblmaier, Laura A Meyer, Mark A Watson, Paula M Fracasso, Linda J Pike, Carolyn J Anderson
• Journal: Journal of nuclear medicine : official publication, Society of Nuclear Medicine (J Nucl Med) Vol. 49 Issue 9 Pg. 1472-9 (Sep 2008) ISSN: 0161-5505 [Print] United States
• PMID: 18703609 (Publication Type: Journal Article, Research Support, N.I.H., Extramural)

Chemical References

• 64Cu-DOTA-cetuximab
• Antibodies, Monoclonal
• Antibodies, Monoclonal, Humanized
• Organometallic Compounds
• ErbB Receptors
• Cetuximab

Topics

• Animals
• Antibodies, Monoclonal (pharmacokinetics, therapeutic use)
• Antibodies, Monoclonal, Humanized
• Cell Line, Tumor
• Cetuximab
• Drug Delivery Systems (methods)
• ErbB Receptors (metabolism)
• Female
• HeLa Cells
• Humans
• Metabolic Clearance Rate
• Mice
• Mice, SCID
• Organ Specificity
• Organometallic Compounds (pharmacokinetics, therapeutic use)
• Radionuclide Imaging
• Statistics as Topic
• Tissue Distribution
• Uterine Cervical Neoplasms (diagnostic imaging, metabolism)