E-cadherin suppresses invasion and promotes metastasis in multiple breast cancer models

E-cadherin (E-cad) mediates cell-cell adhesion and has been proposed to suppress both invasion and metastasis. However, invasive ductal cancers retain E-cad expression in the primary tumor, circulating tumor cells, and distant metastases. We recently demonstrated that cancer cell clusters are efficient metastatic seeds. Since clusters organize through cell-cell adhesion, we tested the requirement for E-cad in genetically engineered mouse models of luminal and basal breast cancer. Loss of E-cad increased invasion and dissemination in 3D culture and in the mammary gland. However, E-cad loss also reduced cancer cell proliferation, survival, tumor cell seeding, and metastatic outgrowth in the lungs. At the transcript level, loss of E-cad was associated with increased apoptosis. Consistent with these results, inhibition of apoptosis partially rescued the metastatic phenotype of E-cad null cancer cells. We therefore propose that E-cad is an invasion suppressor, survival factor, and metastasis promoter in invasive ductal cancers. Overall design: Differential gene expression analysis between organoids isolated from adeno-Cre transduced MMTV-PyMT E-cad+/+ (r = 4 biological replicates) and adeno-Cre transduced MMTV-PyMT E-cadfl/fl (r = 5 biological replicates)

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Padmanaban V, Krol I, Suhail Y, Szczerba BM, Aceto N, Bader JS, Ewald AJ