Highly metastatic MDA-MB-231 tumor cells reduced endothelial cell tight junction (ZO-1)
molecule expression. When cultured without tumor cells, tight junctions were fully established between
adjacent cells. When co-cultured with MDA-MB-231 tumor cells, tight junctions were intermittently expressed
along the edge of contacting endothelial cells, while no change was observed when HBTAEC were co-cultured
with MCF-7 tumor cells. Cell tight junction molecule was stained with ZO-1 antibody (red); cell F-actin
microfilament was stained with phalloidin (green); cell nucleus was counterstained with Hoechst 33342 (blue).