TCF12 Protein Functions as Transcriptional Repressor of E-cadherin, and Its Overexpression Is Correlated with Metastasis of Colorectal Cancer

Abstract

A correlation of TCF12 mRNA overexpression with colorectal cancer (CRC) metastasis was suggested by microarray data and validated by the survey of 120 patients. Thirty-three (27.5%) of the 120 patients showed tumor TCF12 mRNA overexpression and had a higher rate of metastatic occurrence (p ‫؍‬ 0.020) and a poorer survival outcome (p ‫؍‬ 0.014). Abundant TCF12 levels were also observed in human CRC cell lines such as SW620 and LoVo, but a relatively low level was detected in SW480 cells. Knockdown of TCF12 expression in SW620 and LoVo cells drastically reduced their activities of migration, invasion, and metastasis. Tight cell-cell contact and an increase in E-cadherin but a concomitant decrease in fibronectin were observed in TCF12-knockdown cells. Connexin 26, connexin 43, and gapjunction activity were also increased upon TCF12-knockdown. In contrast, ectopic TCF12 overexpression in SW480 cells facilitated fibronectin expression and cell migration and invasion activities but diminished cellular levels of E-cadherin, connexin 26, connexin 43, and gap junction. A physical association of TCF12 with the E-cadherin promoter was evidenced by chromatin immunoprecipitation assay. TCF12 was tightly correlated with cellular expression of Bmi1 and EZH2 and was co-immunoprecipitable with Bmi1 and EZH2, suggesting that TCF12 transcriptionally suppressed E-cadherin expression via polycomb group-repressive complexes. Clinically, TCF12 mRNA overexpression was also correlated with E-cadherin mRNA down-regulation in the tumor tissues of our 120 patients (p ‫؍‬ 0.013). These studies suggested that TCF12 functioned as a transcriptional repressor of E-cadherin and its overexpression was significantly correlated with the occurrence of CRC metastasis.Metastasis is the major cause of colorectal cancer (CRC) 3 mortality. Identification of metastasis-associated genes is essential for understanding the underlying mechanisms, developing new markers for early detection, and ultimately discovering new therapeutic targets. Development of new techniques in proteomic analysis has greatly helped identify molecules involved in the pathogenesis of metastasis (1-3). The advent of microarray technologies has also enhanced the search for genetic factors related to metastasis (4 -6). To identify novel metastasis-associated gene candidates in CRC, this study used microarray technology to determine the gene expression profiles of four CRC patients (two diagnosed with tumors confined in the primary sites and two diagnosed with metastasis). Elevated mRNA expression of the TCF12 gene was observed in the tumor tissues of both patients with metastasis.The product of TCF12 gene (TCF12, also called HTF4 or HEB) is a member of helix-loop-helix (HLH) protein family (7,8). HLH proteins have been divided into seven classes according to their tissue distribution, dimerization abilities, and DNA binding specificities (9). The class I proteins, encoded by TCF3 (E12, E47), TCF4 (E2-2), and TCF12 (HTF4) genes, are also known as E proteins because of their direct DNA (...

Transcription factor binding predicts histone modifications in human cell lines

“…In our analysis, we find REST is positively predictive of H3K27me3 localization, albeit weakly. Instead, we find that binding of TCF12, a TF that has recently been reported to interact with the H3K27me3 methyltransferase EZH2 (19), is the most predictive of H3K27me3 deposition, potentially reflecting differences between human and mouse ES cells. It is remarkable that our model was able to recapitulate such knowledge directly from binding data.…”

“…SP1 binding on human chromosomes 21 and 22 has previously been associated with CpG island promoters (17), which are generally enriched for H3K4me3 (18). The top predictive TF for H3K27me3 in H1 cells, transcription factor 12 (TCF12), has recently been reported as a repressor of E-cadherin in association with the H3K27me3 methylase enhancer of zeste homologue 2 (EZH2) (19). Interestingly, the core pluripotency factor NANOG was predictive of the activation-associated marks in H1 cells and POU5F1 (OCT4) was predictive of H3K9ac and H3K27ac, consistent with their roles in specifying ES cell identity (3).…”

Secreted Heat Shock Protein 90α (HSP90α) Induces Nuclear Factor-κB-mediated TCF12 Protein Expression to Down-regulate E-cadherin and to Enhance Colorectal Cancer Cell Migration and Invasion

“…TCF12 is a class I member of the helix-loop-helix protein family, and tumor TCF12 overexpression was preferentially detected in CRC patients with cancer metastasis (11). Upon knockdown or ectopic overexpression in CRC cell lines, TCF12 was associated with cellular epithelial-mesenchymal transition (EMT) by inducing fibronectin expression and repressing E-cadherin, connexin-26, connexin-43, and gap junction levels.…”

“…Upon knockdown or ectopic overexpression in CRC cell lines, TCF12 was associated with cellular epithelial-mesenchymal transition (EMT) by inducing fibronectin expression and repressing E-cadherin, connexin-26, connexin-43, and gap junction levels. Furthermore, it facilitated CRC cell migration, invasion, and metastasis (11). TCF12 was shown to be physically associated with the promoter region of the E-cadherin gene and coexpressed and co-immunoprecipitated with Bmi1 and EZH2, sug-gesting that TCF12 transcriptionally represses E-cadherin expression via polycomb group-repressive complexes PRC1 and PRC2 (11).…”

Multidimensional Proteomics Reveals a Role of UHRF2 in the Regulation of Epithelial-Mesenchymal Transition (EMT)

“…TWIST2, TCF3 (also known as E47, E2A), TCF7L2 (also known as E2-2, TCF4), FOXC2, and TCF12 are all EMT-TFs and have central roles in the EMT progression (42,44,62). Their activation controls the expression of genes involved in cell polarity, cell-cell contact, cytoskeleton structure and extracellular matrix degradation and contributes to the repression of the epithelial phenotype and induction of the mesenchymal phenotype.…”