Abstract 4112: Mechanisms of transendothelial migration by invasive breast carcinoma cells from patients

The majority of breast cancer related deaths are not due to the primary tumor, but rather to the dissemination of metastatic tumor cells from it to distant sites. Our lab has previously identified the tumor microenvironment of metastasis (TMEM) in mouse and human mammary tumors, sites where transendothelial migration, intravasation and dissemination occur. The constituent cells of TMEM are an endothelial cell, a perivascular TIE2-expressing macrophage (TEM) and an invasive Mena-over expressing tumor cell in direct contact. TMEM are present in human invasive breast tumors and the density of TMEM is positively associated with the risk of developing metastases.Using invasive ductal carcinoma cells of the breast obtained from patients by fine needle aspiration (FNA), we demonstrated that intravasation-directed transendothelial migration (iTEM) of these cancer cells requires macrophages and, depending on clinical subtype, involves either paracrine (macrophage CSF1-R; tumor cell EGFR), or both paracrine and autocrine (tumor cell EGFR + CSF1-R) signaling. Compared to the total population of primary breast cancer cells assayed, cells capable of transendothelial migration expressed relatively high MenaINV and low Mena11a levels, independently of clinical subtype. MenaINV and Mena11a are functionally distinct isoforms of Mena, a key regulator of motility and invasion. Depletion of MenaINV using siRNA showed that MenaINV is required for efficient macrophage-dependent iTEM of tumor cells...

Source: Cancer Research - August 2, 2015 Category: Cancer & Oncology Authors: Pignatelli, J., Jones, J., Chen, X., Smith, B., Flynn, D., Condeelis, J., Oktay, M. Tags: Tumor Biology Source Type: research