Introduction: Epithelial cell adhesion molecule (EpCAM) is a surface glycoprotein highly differentially expressed in many epithelial malignancies. The goal of this study was to evaluate the expression of EpCAM and the potential of MT201 (adecatumumab), a human monoclonal antibody targeting EpCAM, against multiple primary cervical carcinoma cell lines.
Methods: Epithelial cell adhesion molecule expression was evaluated by real-time polymerase chain reaction and flow cytometry in a total of 8 primary cervical cancer cell lines. Sensitivity to MT201-mediated cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity was tested in standard 4-hour 51Cr release assays. To investigate the effect of interleukin-2 (IL-2) on MT201-mediated ADCC, 4-hour 51Cr release assays were also conducted in the presence of low doses of IL-2.
Results: High messenger RNA expression by real-time polymerase chain reaction and high EpCAM surface expression by flow cytometry were detected in 4 (50%) of 8 primary cervical carcinoma cell lines. With no exception, the primary cell lines derived from clinically aggressive tumors showed EpCAM overexpression. Whereas these cell lines were highly resistant to complement-dependent cytotoxicity and natural killer (NK)-dependent cytotoxicity in vitro (range of killing, 4%-19%), EpCAM-positive cell lines showed high sensitivity to MT201-mediated ADCC (range of killing, 23%-59%). Incubation with IL-2 in addition to MT201 significantly increased the cytotoxic activity against EpCAM-positive cervical cancer cell lines (P = 0.007). Addition of human serum also further increased the MT201-mediated killing of EpCAM-positive cell lines (P = 0.03).
Conclusions: Epithelial cell adhesion molecule is highly expressed in primary cervical carcinoma cell lines, and these biologically aggressive tumors are highly sensitive to MT201-mediated cytotoxicity in vitro. MT201 may represent a novel, potentially highly effective treatment option for patients with cervical carcinoma, especially for those with advanced, recurrent, or metastatic disease refractory to standard salvage therapy.
*Division of Gynecologic Oncology, Department of Obstetrics, Gynecology and Reproductive Sciences, Yale University School of Medicine, New Haven, CT; †Micromet AG, Munich, Germany; and ‡Division of Gynecologic Oncology, University of Brescia, Brescia, Italy.
Received May 12, 2010, and in revised form August 23, 2010.
Accepted for publication September 5, 2010.
Address correspondence and reprint requests to Alessandro D. Santin, MD, Yale University School of Medicine, Department of Obstetrics, Gynecology and Reproductive Sciences, Rm 305 LSOG, 333 Cedar St, PO Box 208063, New Haven, CT 06520-8063. E-mail: firstname.lastname@example.org.
This work was supported by grants from the Angelo Novicelli, the Berlucchi and the Camillo Golgi Foundation, Brescia, Italy; NIH R01 CA122728-01A2 to AS; and grants 501/A3/3 and 00227557 from the Italian Institute of Health (ISS) to AS. This investigation was also supported by NIH Research Grant CA-16359 from the National Cancer Institute.
DR is an employee of Micromet AG, Munich, Germany. The other authors declare that they have no competing interests.