Dysregulation of the Hippo pathway occurs in a variety of
cancers and often correlates with a poor prognosis. To further explore the potential role of Hippo pathway dysregulation in
tumor development and progression, we investigated its downstream
transcription factor TEAD4 in
colorectal cancer (CRC). Increased expression and nuclear localization of TEAD4 were found in a significant portion of CRC tissues, in association with
metastasis and a poor prognosis. In CRC cells, TEAD4 knockdown induced the mesenchymal-epithelial transition and decreased cell mobility in vitro and
metastasis in vivo. Microarray analysis revealed that TEAD4 promoted cell adhesion and upregulated the epithelial-mesenchymal transition-related transcriptome in CRC cells.
Vimentin was identified as a new direct target gene mediating TEAD4 function in CRC cells, whereby forced
vimentin expression markedly reversed TEAD4-knockdown-induced cell morphological changes and decreased mobility. Interestingly, rescued expression of both WT TEAD4 and a Y429H mutant can reverse the mesenchymal-epithelial transition and increase
vimentin expression, cell mobility and metastatic potential in TEAD4-knockdown CRC cells. The discrepant expression of YAP and TEAD4 in CRC tissues, the rescue ability of TEAD4 mutant defect in YAP binding and no effect on
vimentin expression by YAP knockdown in CRC cells, all implicated a YAP-independent manner of TEAD4 function in CRC. Furthermore,
vimentin positively correlated and CDH1 reversely correlated with the level of TEAD4 in CRC tissues and xenograft
tumors. Our results suggest that TEAD4 nuclear expression can serve as a
biomarker for CRC progression and poor prognosis. The
transcription factor TEAD4 regulates a pro-
metastasis transcription program in a YAP-independent manner in CRC, thus providing a novel mechanism of TEAD4 transcriptional regulation and its oncogenic role in CRC, independently of the Hippo pathway.