In vitro age-related responses of endothelial cells to breast cancer cell addition

The purpose of this study was to determine if the in vitro age of endothelial cells alters endothelial response(s) to breast cancer cells.

After characterizing lower passage ("young"; passages 10-16) and higher passage ("old"; passages 30-36) bovine pulmonary artery endothelial cells (BPAECs), fluorescently labeled MCF-7 breast cancer cells were added to confluent monolayers of young and old BPAECs.

Transient gaps that peaked in size by 12 h and closed by 48h occurred between the young BPAECs, while large persistent gaps formed between the old BPAECs. Gap formation did not occur when 184A1 cells, a non-malignant mammary epithelial cell line, were added in place of MCF-7 cells, suggesting that the age-related responses of the endothelial cells to MCF-7 cell addition were specific to the tumor cell addition. Additionally, more MCF-7 cells migrated through old BPAEC monolayers, than young BPAEC monolayers, grown on Matrigel-coated filters. Finally, DNA fragmentation and fluorescent annexin-V binding assays suggested increased MCF-7 cell-induced apoptosis in older BPAECs, though results from a caspase-3 activation assay were equivocal.

In sum, our findings support the notion that aged endothelial cells are more susceptible to breast cancer-induced injury, perhaps due to increased apoptosis.