Analysis of the specificity and selectivity of anti-EpCAM antibodies in breast cancer cell lines

The epithelial cell adhesion molecule (EpCAM) is a membrane glycoprotein that is expressed in most normal human epithelia and overexpressed in most carcinomas. Molecule is responsible for cell-to-cell adhesion and additionally participates in signaling, cell migration, proliferation and differentiation. Therefore, EpCAM has been the target of immunotherapy in clinical trials of several solid tumors. It appears to play an important role as a target for circulating tumor cells (CTCs) capturing. The aim of this study was to investigate and compare the specificity and selectivity of different anti-EpCAM antibodies in order to their usefulness for CTCs capturing. All experiments were performed in six different types of breast cancer cell lines (MCF-7, SkBr-3, T47D, CAMA-1, MDAMB-231, BT-20) and with use of three different anti-EpCAM antibodies (EBA-1, AUA-1, 9C4). The experiments revealed that investigated antibodies differ significantly regarding the specificity of EpCAM antigen binding. The most significant role in the circulating tumor cells capturing can play the EBA-1 and 9C4 anti-EpCAM antibodies as they revealed the most specific signal. The strength and specificity of reaction was dependent not only on the type of antibody but also on the type of breast cancer cell line. On the basis of the present outcomes it can be assumed that the best solution for obtaining the most specific results could be the use of mixture of different anti-EpCAM antibodies simultaneously. In conclusion, the proper selection of anti-EpCAM antibody is crucial especially when this antigen is considered as a marker for detection of circulating tumor cells