2296

FOXC1

The existence of microvascular invasion (MVI) formation is one of the most important risk factors predicting poor outcome in hepatocellular carcinoma (HCC) and its mechanism remains largely unknown. epithelial-mesenchymal transition (EMT) has been suggested to be involved in many steps of the invasion-metastasis cascade. To elucidate the possible contribution of EMT to MVI, we initially evaluated the expression of 8 EMT-related transcription factors (TFs) in HCC patients with or without MVI and found that FOXC1 expression was significantly higher in patients with MVI than those without MVI (P < 0.05). Knockdown of FOXC1 expression in HCC cells resulted in a partial conversion of their EMT progresses, mainly regulating the mesenchymal component. Ectopic expression of snail, twist or TGF-beta1 could induce expression of FOXC1, but none of the expression of snail, twist, slug or TGF-beta was consistently down-regulated in response to FOXC1 silencing, suggesting FOXC1 might operate the downstream of other EMT regulators. In addition, knockdown of FOXC1 expression led to cytoskeleton modification accompanied by decreased ability of cell proliferation, migration, and invasion. Meanwhile, some matrix metalloproteinases (MMPs) and VEGF-A were also simultaneously down-regulated. Together, our findings demonstrate that FOXC1 is one of candidate predictive markers of MVI, and that inhibition of FOXC1 expression can partially reverse EMT program, offering a potential molecular therapeutic target for reducing tumor metastasis in HCC patients.

epithelial-to-mesenchymal transition (EMT) is implicated in embryonic development and various pathological events. Transforming growth factor beta (TGFbeta) has been reported to induce EMT in tumor cells, which is a critical step in the process of metastasis leading to cancer spreading and treatment failure. However, the involvement of microRNA during the EMT process in tongue squamous cell carcinoma (TSCC) remains to be determined. To address this question, TSCC cell lines SCC9 and CAL27 were treated with human recombinant TGFbeta1 for 48 h. miRNA microarray illustrated that miR-639 was significantly downregulated in TGFbeta-treated SCC9 cells. Ectopic expression of miR-639 with miRNA mimics effectively blocked TGFbeta-induced EMT in SCC9 and CAL27 cells, but inhibition of miR-639 in SCC9 and CAL27 cells with antisense oligonucleotides induced EMT. Computational microRNA target predictions detected a conserved sequence matching to the seed region of miR-639 in the 3'-UTR of FOXC1 mRNA. Luciferase reporter assays revealed that miR-639 targets FOXC1. Ectopic expression of FOXC1 induces EMT in TSCC cells. Silencing FOXC1 expression blocked TGFbeta-induced EMT in SCC9 cells. Clinically, reduced miR-639 expression was associated with metastasis in TSCC and poor patient survival. The data from the present study suggest that reduced expression of miR-639 underscores the mechanism of TGFbeta-induced EMT in TSCC by targeting FOXC1 and may serve as therapeutic targets in the process of metastasis.CI - (c) 2014 The Authors. cancer Science published by Wiley Publishing Asia Pty Ltd on behalf of Japanese cancer Association.

epithelial-to-mesenchymal transition (EMT) is an important physiologic process that drives tissue formation during development, but also contributes to disease pathogenesis, including fibrosis and cancer metastasis. Elevated expression of the FOXC1 transcription factor has been detected in several metastatic cancers that have undergone EMT. Therefore, mechanistic insight into the role of FOXC1 in the initiation of the EMT process was sought. It was determined that although Foxc1 transcript expression was elevated following TGFbeta1-induced EMT of NMuMG cells, FOXC1 was not required for this induction. RNA sequencing revealed that the mRNA levels of FGF receptor 1-isoform IIIc (Fgfr1-IIIc), normally activated upon TGFbeta1 treatment, were reduced in Foxc1 knockdown cells, and overexpression of Foxc1 was sufficient to induce Fgfr1-IIIc expression, but not EMT. Chromatin immunoprecipitation experiments demonstrated that FOXC1 binds to an Fgfr1 upstream regulatory region and that FOXC1 activates an Fgfr1 promoter element. Furthermore, elevated expression of Foxc1 led to increased Fgfr1-IIIc transcript. Foxc1 knockdown impaired the FGF2-mediated three-dimensional migratory ability of NMuMG cells, which was rescued by expression of FGFR1. In addition, elevated expression of FOXC1 and FGFR1 was also observed in migratory mesenchymal MDA-MB-231 breast cancer cells. Together, these results define a role for FOXC1 in specifying an invasive mesenchymal cell type by promoting FGFR1 isoform switching following induction of TGFbeta1-mediated EMT. Mol cancer Res; 15(10); 1341-53. (c)2017 AACR.CI - (c)2017 American Association for cancer Research.

Glioma is a type of malignant brain tumor. Forkhead box C1 (FOXC1) is a conserved transcription factor that is involved in tumorigenesis; however, the function of FOXC1 in glioma remains unclear. The present study aimed to investigate the effects of FOXC1 silencing on the epithelialtomesenchymal transition (EMT) of glioma cells. FOXC1specific small interfering RNAs were employed to downregulate the expression levels of FOXC1 in glioma cells. The proliferation, migration and invasion of glioma cells were assessed by MTT assay, wound healing assay and Transwell assay. Western blot analysis was performed to reveal the effects of FOXC1 on EMTassociated proteins and betacatenin signaling. The results revealed that, following FOXC1 silencing, the proliferation, migration and invasion of glioma cells were decreased. The expression levels of EMTassociated proteins were also affected. Further examination demonstrated that betacatenin signaling was involved in the effects of FOXC1 on glioma cells. Previous results suggested that overexpression of betacatenin reversed the effects of FOXC1 silencing on glioma cells. The present study demonstrated that FOXC1 may regulate the EMT of glioma cells, potentially via betacatenin signaling. Therefore, FOXC1 may be a potential therapeutic target for the treatment of glioma.