Phenotype-dependent effects of EpCAM expression on growth and invasion of human breast cancer cell lines

Abstract

BackgroundThe epithelial cell adhesion molecule (EpCAM) has been shown to be overexpressed in breast cancer and stem cells and has emerged as an attractive target for immunotherapy of breast cancer patients. This study analyzes the effects of EpCAM on breast cancer cell lines with epithelial or mesenchymal phenotype.MethodsFor this purpose, shRNA-mediated knockdown of EpCAM gene expression was performed in EpCAMhigh breast cancer cell lines with epithelial phenotype (MCF-7, T47D and SkBR3). Moreover, EpCAMlow breast carcinoma cell lines with mesenchymal phenotype (MDA-MB-231, Hs578t) and inducible overexpression of EpCAM were used to study effects on proliferation, migration and in vivo growth.ResultsIn comparison to non-specific silencing controls (n/s-crtl) knockdown of EpCAM (E#2) in EpCAMhigh cell lines resulted in reduced cell proliferation under serum-reduced culture conditions. Moreover, DNA synthesis under 3D culture conditions in collagen was significantly reduced. Xenografts of MCF-7 and T47D cells with knockdown of EpCAM formed smaller tumors that were less invasive. EpCAMlow cell lines with tetracycline-inducible overexpression of EpCAM showed no increased cell proliferation or migration under serum-reduced growth conditions. MDA-MB-231 xenografts with EpCAM overexpression showed reduced invasion into host tissue and more infiltrates of chicken granulocytes.ConclusionsThe role of EpCAM in breast cancer strongly depends on the epithelial or mesenchymal phenotype of tumor cells. Cancer cells with epithelial phenotype need EpCAM as a growth- and invasion-promoting factor, whereas tumor cells with a mesenchymal phenotype are independent of EpCAM in invasion processes and tumor progression. These findings might have clinical implications for EpCAM-based targeting strategies in patients with invasive breast cancer.

Cell adhesion and urothelial bladder cancer: the role of cadherin switching and related phenomena

“…In a murine fibroblast model, Winter et al [126] subsequently demonstrated that this may occur by disruption of the link between a-catenin and F-actin, probably by EpCAM's disruption of the actin cytoskeleton or possibly via p120. In later work, on human breast epithelial cells, Winter et al [127] demonstrated that EpCAM cross-signalling with N-cadherin resulted in the abrogation of cadherin adhesion complexes, mediated by PI(3)K. In breast cancer cell lines, Martowicz et al [128] showed that epithelial cells need EpCAM to promote growth and invasion, yet mesenchymal tumour cells are independent of EpCAM for invasion and progression; Martowicz et al [129] also demonstrated that overexpression of EpCAM in human mammary epithelial cells led to a more proliferative phenotype and downregulation of E-cadherin. There is likely considerable plasticity in these pathways [110], with cells reverting to a less aggressive state by mesenchymal-to-epithelial transition (MET) or by the reversal of the CSC phenotype, and most likely influenced by the tumour microenvironment [23].…”

A breast cancer cell microarray (CMA) as a rapid method to characterize candidate biomarkers

“…4 and Table 1). 22 Notably, the majority of EpCAM-negative cell lines were from the basal subtype and the majority of the luminal cell lines stained positive for EpCAM, which correlates with the epithelial and mesenchymal phenotype that these 2 subtypes exhibit. This suggests that our CMA method could be utilized to make inferences about the roles of proteins by correlating the staining properties with the known biology of the cell lines.…”

“…21 In a study by Martowicz et al investigating the effects of EpCAM expression on the growth and invasion of breast cancer cell lines, the authors showed that those cell lines with epithelial phenotype require EpCAM to promote growth and invasion whereas the cell lines with mesenchymal phenotype are independent of EpCAM to promote these processes. 22 Our staining revealed localization of staining of EpCAM to the plasma membrane (Fig. 4).…”

Establishment of a Human Multiple Myeloma Xenograft Model in the Chicken to Study Tumor Growth, Invasion and Angiogenesis

“…The chorioallantoic membrane (CAM) is a well-established system to study tumor-dependent angiogenesis [20][21][22] . When solid tumors are grafted to the CAM, they display many characteristics of cancers in vivo, including proliferation, invasion, angiogenesis and metastasis [23][24][25][26][27] . Based on the previous experience of our group with CAM xenograft models 20,26,27 , a human MM model was established that combines the advantage of a human 3D culture system with the model of ex ovo developing chicken embryos.…”

“…When solid tumors are grafted to the CAM, they display many characteristics of cancers in vivo, including proliferation, invasion, angiogenesis and metastasis [23][24][25][26][27] . Based on the previous experience of our group with CAM xenograft models 20,26,27 , a human MM model was established that combines the advantage of a human 3D culture system with the model of ex ovo developing chicken embryos. This MM model system allows real time monitoring of MM growth progression, quantification of cell mass and preclinical drug testing.…”