E-cadherin and EMT regulation by bHLH factors: a new role for the class I gene E2-2 (TCF4) and its comparison with E47.

ABSTRACT: Loss of expression of the cell-cell adhesion molecule E-cadherin is an essential event for epithelial-mesenchymal transition (EMT), a process that allows cell migration in the developing embryo and during tumour invasion. Transcriptional repression has emerged as the main mechanism responsible for E-cadherin downregulation in most carcinomas. Recently, we have identified the class I HLH transcriptional regulator E2-2 (ITF2), in a yeast one hybrid screen designed to identify transcriptional repressors interacting with the E-pal element of the murine E-cadherin promoter. The E2-2 gene codifies two isoforms that differ in their N-terminal regions but their specific functions remain unknown. In the present work we show that both E2-2A and E2-2B induce a complete EMT, in MDCK cells, with loss of E-cadherin expression, gain of mesenchymal markers and acquisition of motile and invasive properties. Although both isoforms repress E-cadherin promoter in MDCK cells, only the E2-2B isoform does it in other epithelial cell lines. Notably, we found that E2-2B is upregulated at the mRNA level in MDCK cells after treatment with TGF-beta1, a key regulator of EMT. Upregulation of E2-2A/B factors was confirmed in MDCK cells overexpressing other EMT inducers, Snai1, Snai2 or E47. Interestingly, gene profiling studies indicate that bHLH E2-2 factors induce similar, yet distinct, genetic programs from those induced by bHLH E47 in MDCK cells. These results, together with the expression pattern observed in early mouse embryos, support a new role for E2-2A/B in E-cadherin regulation and EMT, and suggest an interesting interplay between bHLH factors and other E-cadherin repressors.

ORGANISM(S): Canis lupus familiaris Homo sapiens

PROVIDER: GSE9145 | GEO | 2008/12/21

SECONDARY ACCESSION(S): PRJNA102689

REPOSITORIES: GEO