Integrin α6β4 controls the expression of genes associated with cell motility, invasion, and metastasis, including S100A4/metastasin

The integrin α6β4 is associated with carcinoma progression by contributing to apoptosis resistance, invasion, and metastasis, due in part to the activation of select transcription factors. To identify genes regulated by the α6β4 integrin, we compared gene expression profiles of MDA-MB-435 cells that stably express integrin α6β4 (MDA/β4) and vector-only-transfected cells (MDA/mock) using Affymetrix GeneChip® analysis. Our results show that integrin α6β4 altered the expression of 538 genes (p < 0.01). Of these genes, 36 are associated with pathways implicated in cell motility and metastasis, including S100A4/metastasin. S100A4 expression correlated well with integrin α6β4 expression in established cell lines. Suppression of S100A4 by small interference RNA resulted in a reduced capacity of 6/34-expressing cells to invade a reconstituted basement membrane in response to lysophosphatidic acid. Using small interference RNA, promoter analysis, and chromatin immunoprecipitation, we demonstrate that S100A4 is regulated by NFAT5, thus identifying the first target of NFAT5 in cancer. In addition, several genes that are known to be regulated by DNA methylation were up-regulated dramatically by integrin α6β4 expression, including S100A4, FST, PDLIM4, CAPG, and Nkx2.2. Notably, inhibition of DNA methyltransferases stimulated expression of these genes in cells lacking the α6β4 integrin, whereas demethylase inhibitors suppressed expression in α6β4 integrin-expressing cells. Alterations in DNA methylation were confirmed by bisulfate sequencing, thus suggesting that integrin α6β4 signaling can lead to the demethylation of select promoters. In summary, our data suggest that integrin α6β4 confers a motile and invasive phenotype to breast carcinoma cells by regulating proinvasive and prometastatic gene expression.