Epithelial cell adhesion molecule (EpCAM; also known as CD326 or Tacstd1) is a 40 kDa type I transmembrane glycoprotein composed of an extracellular domain, single transmembrane domain, and the intracellular domain Ep1CD1. EpCAM functions in cell adhesion, signaling, differentiation, migration, proliferation, formation and maintenance of organ morphology, and morphogenic movements during gastrulation. Additionally, EpCAM is essential for cell junctions; the AxxxG motif in the transmembrane domain of EpCAM associates directly with claudin-7, an important tight junction protein. EpCAM also suppresses or enhances E-cadherin function depending on the context of the interaction. Mutant animal models have been developed in mouse (at least four global EpCAM knockout types and one conditional knockout), zebrafish, and Xenopus.
Dysregulation and/or mutations are associated with congenital tufting enteropathy (CTE), which causes lethal diarrhea in newborns, cholestatic liver diseases, and cancer1. EpCAM promotes the proliferation of tumors, is involved in tumorigenesis and metastasis, and EpCAM positive cells serve as cancer stem cells for various human cancers. Therapeutic approaches targeting EpCAM are under development to eliminate chemotherapeutic drug resistance in cancer stem cells by conjugating cancer stem cells targeting EpCAM aptamer with a chemotherapeutic drug. Additionally, EpCAM antibody sensitizes chemoresistant myeloid leukemia to innate immune cells, and EpCAM peptide-primed dendritic cell vaccinations exhibit anti-tumor immunity in hepatocellular carcinoma cells.
Monoclonal antibody G8.8 was raised against glycoconjugates isolated from the TE-71 mouse thymic epithelial cell line2. Splenic cell suspensions were fused with X63-Ag8.653 cells and the resulting hybridomas were screened on frozen Balb/c thymus.
