Cellular and complement-dependent cytotoxicity of Ep-CAM-specific monoclonal antibody MT201 against breast cancer cell lines

Abstract

MT201 is a fully human monoclonal IgG1 antibody with moderate affinity for epithelial cell adhesion molecule (Ep-CAM) being clinically developed for the treatment of carcinomas. Like many other clinically validated IgG1 monoclonal antibodies, MT201 primarily acts by antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC). Here, we analysed ADCC and CDC induced by MT201 and, as reference, trastuzumab against a panel of nine human breast cancer cell lines expressing distinct surface levels of Ep-CAM and human epithelial growth factor receptor type 2 antigen. Maximal cell lysis by ADCC by MT201 and trastuzumab in the presence of peripheral mononuclear cells did not significantly differ when averaged over the nine cell lines, but showed marked differences with respect to individual cell lines. The extent of cell lysis at intermediate surface target density was highly variable, suggesting a dominant influence of other susceptibility factors. Only one breast cancer cell line was eliminated via CDC, but only by MT201. Resistance to CDC appeared to correlate with high expression levels of complement resistance factors. Our present data as well as recent data on the prevalence and prognostic relevance of Ep-CAM expression in metastatic breast cancer suggest that Ep-CAM-specific monoclonal IgG1 antibodies may have a significant therapeutic potential in the treatment of breast cancer.

Immunoliposomes: A Multipurpose Strategy in Breast Cancer Targeted Therapy

“…In this case, the selected cell lines were MCF7 and MDA-MB231, both derived from a pleural effusion of a human breast adenocarcinoma; MCF7 is documented to have high expression levels of EpCAM. On the contrary, MDA-MB231 shows a very low expression (Prang, Preithner et al, 2005). To ensure this point, EpCAM expression was analyzed by Western blot using an anti-EpCAM antibody ( Figure 2) in both cell lines, confirming the previously published results.…”

Frequent high-level expression of the immunotherapeutic target Ep-CAM in colon, stomach, prostate and lung cancers

“…The therapeutic effect of this antibody administered alone or in combination with chemotherapy or GM-CSF (Mellstedt et al, 2000) was not conclusive, but it showed a very benign safety profile (Fields et al, 2002;Punt et al, 2002;Hartung et al, 2005). To reduce immunogenicity and enhance antibodydependant cytotoxicity, complement dependant cytotoxicity and serum half-life, humanised antibodies ING-1 (de Bono et al, 2004), 3622W94 (Abdullah et al, 1999;Martin et al, 1999) and fully human IgG1 antibody MT201 (adecatumumab) (Naundorf et al, 2002;Brischwein et al, 2005) were developed. All showed much higher in vitro cytotoxic activity than edrecolomab, but the two high-affinity antibodies ING-1 and 3622W94 turned out to be much less tolerable than edrecolomab due to induction of acute pancreatitis.…”

“…Epithelial cell adhesion molecule was also selected as target for bi-and trispecific antibody therapies. Three T-cell activating, single-chain bispecific antibodies were shown to potently eradicate established and disseminated tumours in immunodeficient and -competent mouse models (Peters et al, 2004;Brischwein et al, 2005;Schlereth et al, 2005a, b), and a related bispecific antibody called E3Bi demonstrated high in-vitro cytotoxicity (Ren-Heidenreich et al, 2004). The trifunctional antibody catumaxomab (anti-Ep-CAM Â anti-CD3) has been safely administered in a phase I/II study to patients suffering from malignant ascites (Stroehlein et al, 2005).…”

“…Currently, a number of Ep-CAM-specific immunotherapies are in phase I and II clinical trials. These are anti-Ep-CAM antibodies ING-1 (de Bono et al, 2004), adecatumumab (Naundorf et al, 2002;Prang et al, 2005), and edrecolomab (Himmler et al, 2003), as well as an immunotoxin (Zimmermann et al, 1997;Di Paolo et al, 2003). It is therefore very important to understand which human cancers are amenable to Ep-CAM-specific immunotherapy based on Ep-CAM expression with respect to intensity, frequency and disease stage.…”

Antibody and Antibody Mimetic Immunotherapeutics

“…As a result of this biological shell game, antibodies evade degradation by serum and lysosomal proteases [5,6]. A region found within Fc is also necessary to induce activation immunotherapeutic mechanisms, such as antibody-dependent cellular cytotoxicity (ADCC) [7,8] or complement-dependent cytotoxicity (CDC) [9,10]. Specifically, Fc γ-receptors on the surface of immune effector cells, such as natural killer cells and macrophages, recognize Fc in antibodies that are bound to disease-relevant receptors on the surface of targeted cells (via interactions involving CDRs within the Fab fragment).…”