The molecular changes that have occurred in breast cancer cells through the introduction of the MZF-1 fragment

We used microarray gene expression analyses to search for epithelial-mesenchymal transition (EMT)-related genes that exhibited the greatest differences in expression in the MZF-1 fragment vector-transfected cells relative to the empty vector-transfected cells. Of the 22,203 genes analyzed in both cell lines, 1209 genes had a two-fold increase and 1557 genes had a two-fold decrease in Hs578T-M(S3) cells (P<0.05), and 1272 genes increased and 1494 genes decreased by a similar amount in MDA-MB-231-M(V4) cells. Combined, 821 of the same genes from both cell lines were up-regulated, and 931 of the same genes from both cell lines were down-regulated. The biological functions of these affected genes were diverse and included 11 EMT-related genes (ITGA5, SERPINE1 GNGI1, SEAP1, TIMP1, FN1, TMEFF1, SNAI2, VIM, CALD1 and MSN) which were down-regulated, and 5 MET-related genes (CDH1, TSPAN13, OCLN, KRT19 and DSP) which were up-regulated. To understand functions of MZF-1/Elk-1 heterodimers, we transfected the binding site-derived peptide to the cells to interrupt heterodimer formation, their DNA binding activity, PKCα expression, cell migration and tumorigenicity were decreased, and the mesenchymal-epithelial transition (MET) was present.