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The NF?B subunit RELA is a master transcriptional regulator of the committed epithelial-mesenchymal transition in airway epithelial cells.

ABSTRACT: The epithelial-mesenchymal transition (EMT) is a multistep dedifferentiation program important in tissue repair. Here, we examined the role of the transcriptional regulator NF-?B in EMT of primary human small airway epithelial cells (hSAECs). Surprisingly, transforming growth factor ? (TGF?) activated NF-?B/RELA proto-oncogene, NF-?B subunit (RELA) translocation within 1 day of stimulation, yet induction of its downstream gene regulatory network occurred only after 3 days. A time course of TGF?-induced EMT transition was analyzed by RNA-Seq in the absence or presence of inducible shRNA-mediated silencing of RELA. In WT cells, TGF? stimulation significantly affected the expression of 2,441 genes. Gene set enrichment analysis identified WNT, cadherin, and NF-?B signaling as the most prominent TGF?-inducible pathways. By comparison, RELA controlled expression of 3,138 overlapping genes mapping to WNT, cadherin, and chemokine signaling pathways. Conducting upstream regulator analysis, we found that RELA controls six clusters of upstream transcription factors, many of which overlapped with a transcription factor topology map of EMT developed earlier. RELA triggered expression of three key EMT pathways: 1) the WNT/?-catenin morphogen pathway, 2) the JUN transcription factor, and 3) the Snail family transcriptional repressor 1 (SNAI1). RELA binding to target genes was confirmed by ChIP. Experiments independently validating WNT dependence on RELA were performed by silencing RELA via genome editing and indicated that TGF?-induced WNT5B expression and downstream activation of the WNT target AXIN2 are RELA-dependent. We conclude that RELA is a master transcriptional regulator of EMT upstream of WNT morphogen, JUN, SNAI1-ZEB1, and interleukin-6 autocrine loops.

SUBMITTER: Tian B

PROVIDER: S-EPMC6200927 | biostudies-literature | 2018 Oct

REPOSITORIES: biostudies-literature

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The NFκB subunit RELA is a master transcriptional regulator of the committed epithelial-mesenchymal transition in airway epithelial cells.

Tian Bing B Widen Steven G SG Yang Jun J Wood Thomas G TG Kudlicki Andrzej A Zhao Yingxin Y Brasier Allan R AR

The Journal of biological chemistry 20180830 42

The epithelial-mesenchymal transition (EMT) is a multistep dedifferentiation program important in tissue repair. Here, we examined the role of the transcriptional regulator NF-κB in EMT of primary human small airway epithelial cells (hSAECs). Surprisingly, transforming growth factor β (TGFβ) activated NF-κB/RELA proto-oncogene, NF-κB subunit (RELA) translocation within 1 day of stimulation, yet induction of its downstream gene regulatory network occurred only after 3 days. A time course of TGFβ- ...[more]

PMID: 30166344

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Project description:Study questionDoes the upregulation of the zinc finger E-box binding homeobox 2 (ZEB2) transcription factor in human trophoblast cells lead to alterations in gene expression consistent with an epithelial-mesenchymal transition (EMT) and a consequent increase in invasiveness?Summary answerOverexpression of ZEB2 results in an epithelial-mesenchymal shift in gene expression accompanied by a substantial increase in the invasive capacity of human trophoblast cells.What is known alreadyIn-vivo results have shown that cytotrophoblast differentiation into extravillous trophoblast involves an epithelial-mesenchymal transition. The only EMT master regulatory factor which shows changes consistent with extravillous trophoblast EMT status and invasive capacity is the ZEB2 transcription factor.Study design, size, durationThis study is a mechanistic investigation of the role of ZEB2 in trophoblast differentiation. We generated stable ZEB2 overexpression clones using the epithelial BeWo and JEG3 choriocarcinoma lines. Using these clones, we investigated the effects of ZEB2 overexpression on the expression of EMT-associated genes and proteins, cell morphology and invasive capability.Participants/materials, setting, methodsWe used lentiviral transduction to overexpress ZEB2 in BeWo and JEG3 cells. Stable clones were selected based on ZEB2 expression and morphology. A PCR array of EMT-associated genes was used to probe gene expression. Protein measurements were performed by western blotting. Gain-of-function was assessed by quantitatively measuring cell invasion rates using a Transwell assay, a 3D bioprinted placenta model and the xCelligenceTM platform.Main results and the role of chanceThe four selected clones (2 × BeWo, 2 × JEG3, based on ZEB2 expression and morphology) all showed gene expression changes indicative of an EMT. The two clones (1 × BeWo, 1 × JEG3) showing >40-fold increase in ZEB2 expression also displayed increased ZEB2 protein; the others, with increases in ZEB2 expression <14-fold did not. The two high ZEB2-expressing clones demonstrated robust increases in invasive capacity, as assessed by three types of invasion assay. These data identify ZEB2-mediated transcription as a key mechanism transforming the epithelial-like trophoblast into cells with a mesenchymal, invasive phenotype.Large scale dataPCR array data have been deposited in the GEO database under accession number GSE116532.Limitations, reasons for cautionThese are in-vitro studies using choriocarcinoma cells and so the results should be interpreted in view of these limitations. Nevertheless, the data are consistent with in-vivo findings and are replicated in two different cell lines.Wider implications of the findingsThe combination of these data with the in-vivo findings clearly identify ZEB2-mediated EMT as the mechanism for cytotrophoblast differentiation into extravillous trophoblast. Having characterized these cellular mechanisms, it will now be possible to identify the intracellular and extracellular regulatory components which control ZEB2 and trophoblast differentiation. It will also be possible to identify the aberrant factors which alter differentiation in invasive pathologies such as preeclampsia and abnormally invasive placenta (AKA accreta, increta, percreta).Study funding and competing interest(s)Funding was provided by the Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine and Surgery at Hackensack Meridian Health, Hackensack, NJ. The 3D bioprinted placental model work done in Drs Kim and Fisher's labs was supported by the Children's National Medical Center. The xCELLigence work done in Dr Birge's lab was supported by NIH CA165077. The authors declare no competing interests.

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Project description:The most frequent alteration in the prostate oncogenome is loss of chromosome (chr) 8p21 that has been associated with loss of NKX3.1 homeobox gene. Chr8p21 deletions increase significantly with tumor grade and are associated with poor prognosis in prostate cancer (PCa), suggesting critical involvement of this region in tumor progression. Recent studies suggest that apart from NKX3.1, this region harbors alternative tumor suppressors that are yet undefined. We proposed a novel, paradigm shifting hypothesis that this locus is associated with a miRNA gene cluster-miR-3622a/b- that plays a crucial suppressive role in PCa. Here we demonstrate the crucial role of miR-3622a in prostate cancer epithelial-to-mesenchymal transition (EMT). MicroRNA expression profiling in microdissected human PCa clinical tissues showed that miR-3622a expression is widely downregulated and is significantly correlated with poor survival outcome and tumor progression. To understand the functional significance of miR-3622a, knockdown and overexpression was performed using non-transformed prostate epithelial and PCa cell lines, respectively, followed by functional assays. Our data demonstrate that endogenous miR-3622a expression is vital to maintain the epithelial state of normal and untransformed prostate cells. miR-3622a expression inhibits EMT, progression and metastasis of PCa in vitro and in vivo. Further, we found that miR-3622a directly targets EMT effectors ZEB1 and SNAI2. In view of these data, we propose that frequent loss of miR-3622a at chr8p21 region leads to induction of EMT states that in turn, promotes PCa progression and metastasis. This study has potentially significant implications in the field of prostate cancer as it identifies an important miRNA component of a frequently lost chromosomal region with critical roles in prostate carcinogenesis which is a highly significant step towards understanding the mechanistic involvement of this locus. Also, our study indicates that miR-3622a is a novel PCa biomarker and potential drug target for developing therapeutic regimens against advanced PCa.

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The NF?B subunit RELA is a master transcriptional regulator of the committed epithelial-mesenchymal transition in airway epithelial cells.

Publications

The NFκB subunit RELA is a master transcriptional regulator of the committed epithelial-mesenchymal transition in airway epithelial cells.

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