scholarly journals RAC1B: A Guardian of the Epithelial Phenotype and Protector Against Epithelial-Mesenchymal Transition

Cells ◽  
2019 ◽  
Vol 8 (12) ◽  
pp. 1569 ◽  
Author(s):  
Rabea Zinn ◽  
Hannah Otterbein ◽  
Hendrik Lehnert ◽  
Hendrik Ungefroren
Keyword(s):  
Gene Expression ◽  
Cell Migration ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Small Gtpase ◽  
Mitogen Activated Protein Kinase ◽  
Ductal Adenocarcinoma ◽  
Mesenchymal Transition ◽  
Migratory Activity ◽  
Tgf Β1

The small GTPase Ras-related C3 botulinum toxin substrate 1B (RAC1B) has been shown to potently inhibit transforming growth factor (TGF)-β1-induced cell migration and epithelial-mesenchymal transition (EMT) in pancreatic and breast epithelial cells, but the underlying mechanism has remained obscure. Using a panel of pancreatic ductal adenocarcinoma (PDAC)-derived cell lines of different differentiation stages, we show that RAC1B is more abundantly expressed in well differentiated as opposed to poorly differentiated cells. Interestingly, RNA interference-mediated knockdown of RAC1B decreased expression of the epithelial marker protein E-cadherin, encoded by CDH1, and enhanced its TGF-β1-induced downregulation, whereas ectopic overexpression of RAC1B upregulated CDH1 expression and largely prevented its TGF-β1-induced silencing of CDH1. Conversely, knockdown of RAC1B, or deletion of the RAC1B-specific exon 3b by CRISPR/Cas-mediated genomic editing, enhanced basal and TGF-β1-induced upregulation of mesenchymal markers like Vimentin, and EMT-associated transcription factors such as SNAIL and SLUG. Moreover, we demonstrate that knockout of RAC1B enhanced the cells’ migratory activity and derepressed TGF-β1-induced activation of the mitogen-activated protein kinase ERK2. Pharmacological inhibition of ERK1/2 activation in RAC1B-depleted cells rescued cells from the RAC1B knockdown-induced enhancement of cell migration, TGF-β1-induced downregulation of CDH1, and upregulation of SNAI1. We conclude that RAC1B promotes epithelial gene expression and suppresses mesenchymal gene expression by interfering with TGF-β1-induced MEK-ERK signaling, thereby protecting cells from undergoing EMT and EMT-associated responses like acquisition of cell motility.

scholarly journals RAC1B Regulation of TGFB1 Reveals an Unexpected Role of Autocrine TGFβ1 in the Suppression of Cell Motility

Cancers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 3570
Author(s):  
Hendrik Ungefroren ◽  
Hannah Otterbein ◽  
Ulrich F. Wellner ◽  
Tobias Keck ◽  
Hendrik Lehnert ◽  
...  
Keyword(s):  
Cell Motility ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Small Gtpase ◽  
Ductal Adenocarcinoma ◽  
Type I ◽  
Dependent Manner ◽  
Mesenchymal Transition ◽  
Migratory Activity ◽  
Downstream Effectors

Autocrine transforming growth factor (TGF)β has been implicated in epithelial-mesenchymal transition (EMT) and invasion of several cancers including pancreatic ductal adenocarcinoma (PDAC) as well as triple-negative breast cancer (TNBC). However, the precise mechanism and the upstream inducers or downstream effectors of endogenous TGFB1 remain poorly characterized. In both cancer types, the small GTPase RAC1B inhibits cell motility induced by recombinant human TGFβ1 via downregulation of the TGFβ type I receptor, ALK5, but whether RAC1B also impacts autocrine TGFβ signaling has not yet been studied. Intriguingly, RNA interference-mediated knockdown (RNAi-KD) or CRISPR/Cas-mediated knockout of RAC1B in TGFβ1-secreting PDAC-derived Panc1 cells resulted in a dramatic decrease in secreted bioactive TGFβ1 in the culture supernatants and TGFB1 mRNA expression, while the reverse was true for TNBC-derived MDA-MB-231 cells ectopically expressing RAC1B. Surprisingly, the antibody-mediated neutralization of secreted bioactive TGFβ or RNAi-KD of the endogenous TGFB1 gene, was associated with increased rather than decreased migratory activities of Panc1 and MDA-MB-231 cells, upregulation of the promigratory genes SNAI1, SNAI2 and RAC1, and downregulation of the invasion suppressor genes CDH1 (encoding E-cadherin) and SMAD3. Intriguingly, ectopic re-expression of SMAD3 was able to rescue Panc1 and MDA-MB-231 cells from the TGFB1 KD-induced rise in migratory activity. Together, these data suggest that RAC1B favors synthesis and secretion of autocrine TGFβ1 which in a SMAD3-dependent manner blocks EMT-associated gene expression and cell motility.

scholarly journals Rapid Up-Regulation of α4 Integrin-mediated Leukocyte Adhesion by Transforming Growth Factor-β1

2003 ◽  
Vol 14 (1) ◽  
pp. 54-66 ◽  
Author(s):  
Rubén A. Bartolomé ◽  
Francisco Sanz-Rodrı́guez ◽  
Mar M. Robledo ◽  
Andrés Hidalgo ◽  
Joaquin Teixidó
Keyword(s):  
Cell Migration ◽  
Cell Adhesion ◽  
Growth Factor ◽  
Transforming Growth Factor ◽  
Human Peripheral Blood ◽  
Transforming Growth Factor Β1 ◽  
Small Gtpase ◽  
Mitogen Activated Protein Kinase ◽  
Intracellular Camp ◽  
Tgf Β1

The α4 integrins (α4β1 and α4β7) are cell surface heterodimers expressed mostly on leukocytes that mediate cell-cell and cell-extracellular matrix adhesion. A characteristic feature of α4 integrins is that their adhesive activity can be subjected to rapid modulation during the process of cell migration. Herein, we show that transforming growth factor-β1 (TGF-β1) rapidly (0.5–5 min) and transiently up-regulated α4 integrin-dependent adhesion of different human leukocyte cell lines and human peripheral blood lymphocytes (PBLs) to their ligands vascular cell adhesion molecule-1 (VCAM-1) and connecting segment-1/fibronectin. In addition, TGF-β1 enhanced the α4 integrin-mediated adhesion of PBLs to tumor necrosis factor-α–treated human umbilical vein endothelial cells, indicating the stimulation of α4β1/VCAM-1 interaction. Although TGF-β1 rapidly activated the small GTPase RhoA and the p38 mitogen-activated protein kinase, enhanced adhesion did not require activation of both signaling molecules. Instead, polymerization of actin cytoskeleton triggered by TGF-β1 was necessary for α4 integrin-dependent up-regulated adhesion, and elevation of intracellular cAMP opposed this up-regulation. Moreover, TGF-β1 further increased cell adhesion mediated by α4 integrins in response to the chemokine stromal cell-derived factor-1α. These data suggest that TGF-β1 can potentially contribute to cell migration by dynamically regulating cell adhesion mediated by α4 integrins.

scholarly journals Melatonin Inhibits Transforming Growth Factor-β1-Induced Epithelial–Mesenchymal Transition in AML12 Hepatocytes

Biology ◽  
2019 ◽  
Vol 8 (4) ◽  
pp. 84 ◽  
Author(s):  
Kim ◽  
Park ◽  
Kim ◽  
Leem ◽  
Park
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Protective Action ◽  
Transforming Growth Factor Β1 ◽  
Membrane Receptors ◽  
Mitogen Activated Protein Kinase ◽  
Independent Manner ◽  
Mesenchymal Transition ◽  
Tgf Β1

Recent studies showed that melatonin, a well-known pineal hormone that modulates the circadian rhythm, exerts beneficial effects against liver fibrosis. However, mechanisms for its protective action against the fibrotic processes remain incompletely understood. Here, we aimed to explore the effects of the hormone on transforming growth factor-β1 (TGF-β1)-stimulated epithelial–mesenchymal transition (EMT) in AML12 hepatocytes. Pretreatment with melatonin dose-dependently reversed downregulation of an epithelial marker and upregulation of mesenchymal markers after TGF-β1 stimulation. Additionally, melatonin dose-dependently suppressed an increased phosphorylation of Smad2/3 after TGF-β1 treatment. Besides the canonical Smad signaling pathway, an increase in phosphorylation of extracellular signal-regulated kinase 1/2 and p38 was also dose-dependently attenuated by melatonin. The suppressive effect of the hormone on EMT stimulated by TGF-β1 was not affected by luzindole, an antagonist of melatonin membrane receptors, suggesting that its membrane receptors are not required for the inhibitory action of melatonin. Moreover, melatonin suppressed elevation of intracellular reactive oxygen species (ROS) levels in TGF-β1-treated cells. Finally, TGF-β1-stimulated EMT was also inhibited by the antioxidant N-acetylcysteine. Collectively, these results suggest that melatonin prevents TGF-β1-stimulated EMT through suppression of Smad and mitogen-activated protein kinase signaling cascades by deactivating ROS-dependent mechanisms in a membrane receptor-independent manner.

scholarly journals Partial epithelial-mesenchymal transition in keloid scars: regulation of keloid keratinocyte gene expression by transforming growth factor-β1

2016 ◽  
Vol 4 ◽  
pp. 1-17 ◽  
Author(s):  
Jennifer M. Hahn ◽  
Kevin L. McFarland ◽  
Kelly A. Combs ◽  
Dorothy M. Supp
Keyword(s):  
Gene Expression ◽  
Wound Healing ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Normal Skin ◽  
Mesenchymal Transition ◽  
Keloid Scar ◽  
Normal Keratinocytes ◽  
Keloid Scars ◽  
Tgf Β1

Abstract Background Keloids are an extreme form of abnormal scarring that result from a pathological fibroproliferative wound healing process. The molecular mechanisms driving keloid pathology remain incompletely understood, hindering development of targeted, effective therapies. Recent studies in our laboratory demonstrated that keloid keratinocytes exhibit adhesion abnormalities and display a transcriptional signature reminiscent of cells undergoing epithelial-mesenchymal transition (EMT), suggesting a role for EMT in keloid pathology. In the current study, we further define the EMT-like phenotype of keloid scars and investigate regulation of EMT-related genes in keloid. Methods Primary keratinocytes from keloid scar and normal skin were cultured in the presence or absence of transforming growth factor beta 1 (TGF-β1) +/− inhibitors of TGF-β1 and downstream signaling pathways. Gene expression was measured using quantitative polymerase chain reaction. Migration was analyzed using an in vitro wound healing assay. Proteins in keloid scar and normal skin sections were localized by immunohistochemistry. Statistical analyses utilized SigmaPlot (SyStat Software, San Jose, CA) or SAS® (SAS Institute, Cary, NC). Results In keloid and normal keratinocytes, TGF-β1 regulated expression of EMT-related genes, including hyaluronan synthase 2, vimentin, cadherin-11, wingless-type MMTV integration site family, member 5A, frizzled 7, ADAM metallopeptidase domain 19, and interleukin-6. Inhibition of canonical TGF-β1 signaling in keloid keratinocytes significantly inhibited expression of these genes, and TGF-β1 stimulation of normal keratinocytes increased their expression. The inhibition of the extracellular signal-regulated kinase 1/2 (ERK1/2) signaling pathway or the p38 mitogen-activated protein kinase pathway attenuated TGF-β1-induced expression of subsets of these genes. Migration of keloid keratinocytes, previously shown to be increased compared with normal keratinocytes, was significantly reduced by inhibition of TGF-β1 or ERK1/2 signaling. Biomarkers of EMT, including reduced E-cadherin and increased active β-catenin, were observed in keloid epidermis in vivo. However, evidence of basement membrane breakdown in keloid scar was not observed. Conclusions The results suggest that keloid keratinocytes exist in an EMT-like metastable state, similar to activated keratinocytes in healing wounds. The EMT-like gene expression pattern of keloid keratinocytes is regulated by canonical and non-canonical TGF-β1 signaling pathways. Therefore, interventions targeting TGF-β1-regulated EMT-like gene expression in keloid keratinocytes may serve to suppress keloid scarring.

scholarly journals Long non-coding (lnc)RNA profiling and the role of a key regulator lnc-PNRC2-1 in the transforming growth factor-β1-induced epithelial–mesenchymal transition of CNE1 nasopharyngeal carcinoma cells

2021 ◽  
Vol 49 (3) ◽  
pp. 030006052199651
Author(s):  
Jie Yang ◽  
Enzi Feng ◽  
Yanxin Ren ◽  
Shun Qiu ◽  
Liufang Zhao ◽  
...  
Keyword(s):  
Growth Factor ◽  
Nasopharyngeal Carcinoma ◽  
Rna Sequencing ◽  
Western Blotting ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Carcinoma Cells ◽  
Mesenchymal Transition ◽  
Emt Markers ◽  
Tgf Β1

Objectives To identify key long non-coding (lnc)RNAs responsible for the epithelial–mesenchymal transition (EMT) of CNE1 nasopharyngeal carcinoma cells and to investigate possible regulatory mechanisms in EMT. Methods CNE1 cells were divided into transforming growth factor (TGF)-β1-induced EMT and control groups. The mRNA and protein expression of EMT markers was determined by real-time quantitative PCR and western blotting. Differentially expressed genes (DEGs) between the two groups were identified by RNA sequencing analysis, and DEG functions were analyzed by gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses. EMT marker expression was re-evaluated by western blotting after knockdown of a selected lncRNA. Results TGF-β1-induced EMT was characterized by decreased E-cadherin and increased vimentin, N-cadherin, and Twist expression at both mRNA and protein levels. Sixty lncRNA genes were clustered in a heatmap, and mRNA expression of 14 dysregulated lncRNAs was consistent with RNA sequencing. Knockdown of lnc-PNRC2-1 increased expression of its antisense gene MYOM3 and reduced expression of EMT markers, resembling treatment with the TGF-β1 receptor inhibitor LY2109761. Conclusion Various lncRNAs participated indirectly in the TGF-β1-induced EMT of CNE1 cells. Lnc-PNRC2-1 may be a key regulator of this and is a potential target to alleviate CNE1 cell EMT.

scholarly journals Pancreatic Cancers with High Grade Tumor Budding Exhibit Hallmarks of Diminished Anti-Tumor Immunity

Cancers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 1090
Author(s):  
Hassan Sadozai ◽  
Animesh Acharjee ◽  
Thomas Gruber ◽  
Beat Gloor ◽  
Eva Karamitopoulou
Keyword(s):  
Gene Expression ◽  
Pancreatic Cancer ◽  
Disease Progression ◽  
Immune Escape ◽  
Epithelial Mesenchymal Transition ◽  
Tumor Budding ◽  
Ductal Adenocarcinoma ◽  
Low Grade ◽  
High Grade ◽  
Mesenchymal Transition

Tumor budding is associated with epithelial-mesenchymal transition and diminished survival in a number of cancer types including pancreatic ductal adenocarcinoma (PDAC). In this study, we dissect the immune landscapes of patients with high grade versus low grade tumor budding to determine the features associated with immune escape and disease progression in pancreatic cancer. We performed immunohistochemistry-based quantification of tumor-infiltrating leukocytes and tumor bud assessment in a cohort of n = 111 PDAC patients in a tissue microarray (TMA) format. Patients were divided based on the ITBCC categories of tumor budding as Low Grade (LG: categories 1 and 2) and High Grade (HG: category 3). Tumor budding numbers and tumor budding grade demonstrated a significant association with diminished overall survival (OS). HG cases exhibit notably reduced densities of stromal (S) and intratumoral (IT) T cells. HG cases also display lower M1 macrophages (S) and increased M2 macrophages (IT). These findings were validated using gene expression data from TCGA. A published tumor budding gene signature demonstrated a significant association with diminished survival in PDAC patients in TCGA. Immune-related gene expression revealed an immunosuppressive TME in PDAC cases with high expression of the budding signature. Our findings highlight a number of immune features that permit an improved understanding of disease progression and EMT in pancreatic cancer.

scholarly journals Involvement of the ERK/HIF-1α/EMT Pathway in XCL1-Induced Migration of MDA-MB-231 and SK-BR-3 Breast Cancer Cells

2020 ◽  
Vol 22 (1) ◽  
pp. 89
Author(s):  
Ha Thi Thu Do ◽  
Jungsook Cho
Keyword(s):  
Breast Cancer ◽  
Cell Migration ◽  
Cancer Cells ◽  
Cancer Progression ◽  
Chemokine Receptor ◽  
Intracellular Signaling ◽  
Breast Cancer Cells ◽  
Epithelial Mesenchymal Transition ◽  
Mitogen Activated Protein Kinase ◽  
Mesenchymal Transition

Chemokine–receptor interactions play multiple roles in cancer progression. It was reported that the overexpression of X-C motif chemokine receptor 1 (XCR1), a specific receptor for chemokine X-C motif chemokine ligand 1 (XCL1), stimulates the migration of MDA-MB-231 triple-negative breast cancer cells. However, the exact mechanisms of this process remain to be elucidated. Our study found that XCL1 treatment markedly enhanced MDA-MB-231 cell migration. Additionally, XCL1 treatment enhanced epithelial–mesenchymal transition (EMT) of MDA-MB-231 cells via E-cadherin downregulation and upregulation of N-cadherin and vimentin as well as increases in β-catenin nucleus translocation. Furthermore, XCL1 enhanced the expression of hypoxia-inducible factor-1α (HIF-1α) and phosphorylation of extracellular signal-regulated kinase (ERK) 1/2. Notably, the effects of XCL1 on cell migration and intracellular signaling were negated by knockdown of XCR1 using siRNA, confirming XCR1-mediated actions. Treating MDA-MB-231 cells with U0126, a specific mitogen-activated protein kinase kinase (MEK) 1/2 inhibitor, blocked XCL1-induced HIF-1α accumulation and cell migration. The effect of XCL1 on cell migration was also evaluated in ER-/HER2+ SK-BR-3 cells. XCL1 also promoted cell migration, EMT induction, HIF-1α accumulation, and ERK phosphorylation in SK-BR-3 cells. While XCL1 did not exhibit any significant impact on the matrix metalloproteinase (MMP)-2 and -9 expressions in MDA-MB-231 cells, it increased the expression of these enzymes in SK-BR-3 cells. Collectively, our results demonstrate that activation of the ERK/HIF-1α/EMT pathway is involved in the XCL1-induced migration of both MDA-MB-231 and SK-BR-3 breast cancer cells. Based on our findings, the XCL1–XCR1 interaction and its associated signaling molecules may serve as specific targets for the prevention of breast cancer cell migration and metastasis.

scholarly journals Effects of Pyrrole-Imidazole Polyamides Targeting Human TGF-β1 on the Malignant Phenotypes of Liver Cancer Cells

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2883 ◽  
Author(s):  
Keiko Takagi ◽  
Yutaka Midorikawa ◽  
Tadatoshi Takayama ◽  
Hayato Abe ◽  
Kyoko Fujiwara ◽  
...  
Keyword(s):  
Liver Cancer ◽  
Cancer Cells ◽  
Transforming Growth Factor ◽  
Epithelial Mesenchymal Transition ◽  
Tumor Grade ◽  
Expression Level ◽  
Mrna Levels ◽  
Mesenchymal Transition ◽  
Liver Cancer Cells ◽  
Tgf Β1

Synthetic pyrrole-imidazole (PI) polyamides bind to the minor groove of double-helical DNA with high affinity and specificity, and inhibit the transcription of corresponding genes. In liver cancer, transforming growth factor (TGF)-β expression is correlated with tumor grade, and high-grade liver cancer tissues express epithelial-mesenchymal transition markers. TGF-β1 was reported to be involved in cancer development by transforming precancer cells to cancer stem cells (CSCs). This study aimed to evaluate the effects of TGF-β1-targeting PI polyamide on the growth of liver cancer cells and CSCs and their TGF-β1 expression. We analyzed TGF-β1 expression level after the administration of GB1101, a PI polyamide that targets human TGF-β1 promoter, and examined its effects on cell proliferation, invasiveness, and TGF-β1 mRNA expression level. GB1101 treatment dose-dependently decreased TGF-β1 mRNA levels in HepG2 and HLF cells, and inhibited HepG2 colony formation associated with downregulation of TGF-β1 mRNA. Although GB1101 did not substantially inhibit the proliferation of HepG2 cells compared to untreated control cells, GB1101 significantly suppressed the invasion of HLF cells, which displayed high expression of CD44, a marker for CSCs. Furthermore, GB1101 significantly inhibited HLF cell sphere formation by inhibiting TGF-β1 expression, in addition to suppressing the proliferation of HLE and HLF cells. Taken together, GB1101 reduced TGF-β1 expression in liver cancer cells and suppressed cell invasion; therefore, GB1101 is a novel candidate drug for the treatment of liver cancer.

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