• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.4
• /
• pp.199-204
• /
• 2009

Purpose: The purpose of this study is to investigate the epithelial-mesenchymal transition (EMT) induced by Snail transcription factor and Snail-transfected in vivo tumors with histopathological features. Materials and methods: We induced in vivo xenografted tumorigenesis in the oral vestibules of nude mice by a Snail transfected HaCaT cell line and investigated morphological and immunohistochemical features in Snail expressive tumors. Results: We identified tumor masses in 14 out of 15 nude mice in the HaCaT-Snail cell inoculation group, but no tumors were present in any of the HaCaT cell inoculation group. Induced tumors showed features of poorly differentiated carcinoma with invasion to neighboring muscles and bones. The HaCaT-Snail tumors showed decreased expressions of E-cadherin and cytokeratin, but showed increased expressions of vimentin and N-cadherin. Discussion: The Snail transfected xenograft can improve productivity of malignant tumors, show various histopathological features including invasive growth, and aid in the investigation of tumor progression and the interaction with surrounding tissues.

• Journal of Life Science
• /
• v.22 no.8
• /
• pp.1018-1023
• /
• 2012

Snail is a zinc finger transcription factor that induces epithelial-to-mesenchymal transition (EMT), which promotes tumor invasion and metastasis by repressing E-cadherin expression. In addition, Snail restricts the cellular apoptotic response to apoptotic stimuli or survival factor withdrawal; however, its molecular mechanism remains largely unknown. In this study, we have investigated the mechanism underlying Snail-mediated chemoresistance to 5-fluorouracil (5-FU), one of the most widely used anti-cancer drugs. When Snail was overexpressed by doxycycline (DOX) in MCF-7 #5 cells, it inhibited 5-FU-induced apoptotic cell death and switched the cell death mode to necrosis. Snail expression, either by DOX treatment in MCF-7 #5 cells or by the transfection of Snail expression vectors pCR3.1-Snail-Flg, phosphorylation-resistant pCR3.1-S104, and 107A Snail-Flg in MCF-7 cells specifically induced PTEN down-regulation/inactivation and Akt/PKB activation, without affecting ERK1/2 activity. In addition, Snail prominently suppressed 5-FU-induced increases in p53 levels. These findings demonstrate that Snail switches 5-FU-induced apoptosis to necrosis through the activation of Akt/PKB and the down-regulation of p53 levels.

• Journal of Life Science
• /
• v.27 no.11
• /
• pp.1245-1255
• /
• 2017

Most cancer cells produce ATP predominantly through glycolysis instead of through mitochondrial oxidative phosphorylation, even in the presence of oxygen. The phenomenon is termed the Warburg effect, or the glycolytic switch, and it is thought to increase the availability of biosynthetic precursors for cell proliferation. EMTs have critical roles in the initiation of the invasion and metastasis of cancer cells. The glycolytic switch and EMT are important for tumor development and progression; however, their correlation with tumor progression is largely unknown. The Snail transcription factor is a major factor involved in EMT. The Snail expression is regulated by distal-less homeobox 2 (Dlx-2), a homeodomain transcription factor that is involved in embryonic and tumor development. The Dlx-2/Snail cascade is involved in Wnt-induced EMTs and the glycolytic switch. This study showed that in response to Wnt signaling, the Dlx-2/Snail cascade induces the expression of PFKFB2, which is a glycolytic enzyme that synthesizes and degrades fructose 2, 6-bisphosphate (F2,6BP). It also showed that PFKFB2 shRNA prevents Wnt-induced EMTs in the breast-tumor cell line MCF-7. The prevention indicated that glycolysis is linked to Wnt-induced EMT. Additionally, this study showed PFKFB2 shRNA suppresses in vivo tumor metastasis and growth. Finally, it showed the PFKFB2 expression is higher in breast, colon and ovarian cancer tissues than in matched normal tissues regardless of the cancers' stages. The results demonstrated that PFKFB2 is an important regulator of EMTs and metastases induced by the Wnt, Dlx-2 and Snail factors.

• Asian Pacific Journal of Cancer Prevention
• /
• v.16 no.9
• /
• pp.4065-4069
• /
• 2015

Background: Epidermal growth factor-like domain multiple 7 (EGFL7), a secreted protein specifically expressed by endothelial cells during embryogenesis, recently was identified as a critical gene in tumor metastasis. Epithelial-mesenchymal transition (EMT) was found to be closely related with tumor progression. Accordingly, it is important to investigate the migration and EMT change after knock-down of EGFL7 gene expression in human pancreatic cancer cells. Materials and Methods: EGFL7 expression was firstly testified in 4 pancreatic cancer cell lines by real-time polymerase chain reaction (Real-time PCR) and western blot, and the highest expression of EGFL7 was found in PANC-1 cell line. Then, PANC-1 cells transfected with small interference RNA (siRNA) of EGFL7 using plasmid vector were named si-PANC-1, while transfected with negative control plasmid vector were called NC-PANC-1. Transwell assay was used to analyze the migration of PANC-1 cells. Real-time PCR and western blotting were used to detect the expression change of EGFL7 gene, EMT markers like E-Cadherin, N-Cadherin, Vimentin, Fibronectin and transcription factors like snail, slug in PANC-1, NCPANC-1, and si-PANC-1 cells, respectively. Results: After successful plasmid transfection, EGFL7 gene were dramatically knock-down by RNA interference in si-PANC-1 group. Meanwhile, migration ability decreased significantly, compared with PANC-1 and NC-PANC-1 group. Meanwhile, the expression of epithelial phenotype marker E-Cadherin increased and that of mesenchymal phenotype markers N-Cadherin, Vimentin, Fibronectin dramatically decreased in si-PANC-1 group, indicating a reversion of EMT. Also, transcription factors snail and slug decreased significantly after RNA interference. Conclusions: Current study suggested that highly-expressed EGFL7 promotes migration of PANC-1 cells and acts through transcription factors snail and slug to induce EMT, and further study is needed to confirm this issue.

• BMB Reports
• /
• v.48 no.9
• /
• pp.525-530
• /
• 2015

Activation of the Wnt/β-catenin pathway plays a pathogenic role in age-related macular degeneration (AMD) and is thus a potential target for the development of therapeutics for this disease. Here, we demonstrated that Wnt5a antagonized β-catenin response transcription (CRT) induced with Wnt3a by promoting β-catenin phosphorylation at Ser33/Ser37/Thr41 and its subsequent degradation in human retinal pigment epithelial (RPE) cells. Wnt5a decreased the levels of vascular endothelial growth factor (VEGF), tumor necrosis factor-α(TNF-α), and nuclear factor-κB (NF-κB), which was up-regulated by Wnt3a. Furthermore, Wnt5a increased E-cadherin expression and decreased cell migration by down-regulating Snail expression, thereby abrogating the Wnt3a-induced epithelial-mesenchymal transition (EMT) in human RPE cells. Our findings suggest that Wnt5a suppresses the pathogenic effects of canonical Wnt signaling in human RPE cells by promoting β-catenin phosphorylation and degradation. Therefore, Wnt5a has significant therapeutic potential for the treatment of AMD. [BMB Reports 2015; 48(9): 525-530]

• Biomolecules & Therapeutics
• /
• v.31 no.2
• /
• pp.210-218
• /
• 2023

Prostate cancer is the fifth leading cause of cancer-related mortality in men, primarily because of treatment resistance, recurrence, and metastasis. In the present study, we investigated the role of paracrine interleukin-8 (IL-8) in the antagonistic expression of IL-8 and androgen receptor (AR), and the contribution of IL-8 to prostate cancer aggressiveness. In hormone-responsive LNCaP cells that do not express IL-8, recombinant IL-8 treatment significantly increased expressions of IL-8, CXC chemokine receptor 2 (CXCR2), matrix metalloproteinase (MMP)-2/9, Snail, and vimentin. IL-8 treatment significantly decreased AR and E-cadherin expression. IL-8-induced gene expression changes were suppressed by navarixin, a CXCR1/2 inhibitor, and gallein, a Gβγ inhibitor. In PC-3 androgen-refractory prostate cancer cells, IL-8 knockdown reduced expressions of CXCR2, MMP-2/9, Snail, and vimentin, and increased AR and E-cadherin expressions at the mRNA and protein levels. Co-culture with MEG-01 human megakaryocytic cells secreting high levels of IL-8 induced gene expression changes in both LNCaP and PC-3 cells, similar to those induced by IL-8 treatment. The altered gene expressions were accompanied by significant activation of transcription factor Snail in LNCaP and PC-3 cells. Treatment with the CXCR blocker navarixin inhibited the invasion of PC-3 cells but not LNCaP cells. However, invasion induced by MEG-01 was inhibited by navarixin in both LNCaP and PC-3 cells. The collective findings demonstrate that IL-8 enhances CXCR2 expression, which antagonistically regulates AR expression. More importantly, through changes in IL-8/CXCR2-regulated gene expression, IL-8 induces antiandrogen therapy resistance and epithelial-mesenchymal transition in prostate cancer.

• Korean Journal of Clinical Laboratory Science
• /
• v.50 no.3
• /
• pp.337-344
• /
• 2018

Hepatocellular carcinoma (HCC), a major type of hepatoma, is associated with high recurrence and mortality because of its uncontrolled metastatic feature. Silymarin is a polyphenolic flavonoid from Silybum marianun (milk thistle) and exhibits anti-carcinogenic activity through modulation of the epithelial-mesenchymal transition (EMT) in several cancer cells. In this study, the inhibitory mechanism of silymarin against migration and invasion was investigated in the Huh7 HCC cell line. Wound healing and in vitro invasion assays were conducted to examine the effects of silymarin on migration and invasion. Western blot analysis was also applied to evaluate the inhibitory effects of silymarin on the EMT-related genes and their upstream signaling molecules. Silymarin inhibited the migratory and invasive activities of Huh7 cells. In addition, silymarin attenuated the protein expression levels of vimentin and matrix metalloproteinase (MMP)-9 as well as their transcription factors, Snail, and nuclear factor $(NF)-{\kappa}B$, while the expression of E-cadherin was increased by the silymarin treatment. Among the upstream signaling molecules, the phosphorylation of Akt was inhibited by the silymarin treatment, which was confirmed by the selective inhibitor, LY294002. Consequently, silymarin inhibited the invasive and migratory activities in Huh7 cells through the modulation of EMT-related gene expression by the PI3K/Akt signaling pathway, which may have potential as a chemopreventive agent against HCC metastasis.

• Journal of Life Science
• /
• v.29 no.1
• /
• pp.9-17
• /
• 2019

As tumors develop, they encounter microenvironmental stress, such as hypoxia and glucose depletion, due to poor vascular function, thereby leading to necrosis, which is observed in solid tumors. Necrotic cells are known to release cellular cytoplasmic contents, such as high mobility group box 1 (HMGB1), into the extracellular space. The release of HMGB1, a proinflammatory and tumor-promoting cytokine, plays an important role in promoting inflammation and metabolism during tumor development. Recently, HMGB1 was shown to induce the epithelial-mesenchymal transition (EMT) and metastasis. However, the underlying mechanism of the HMGB1-induced EMT, invasion, and metastasis is unclear. In this study, we showed that noninvasive breast cancer cells MCF-7 formed tightly packed, rounded spheroids and that the cells in the inner regions of a multicellular tumor spheroid (MTS), an in vitro model of a solid tumor, led to necrosis due to an insufficient supply of O2 and glucose. In addition, after 7 d of MTS culture, the EMT was induced via the transcription factor Snail. We also showed that HMGB1 receptors, including RAGE, TLR2, and TLR4, were induced by MTS culture. RAGE, TLR2, and TLR4 shRNA inhibited MTS growth, supporting the idea that RAGE/TLR2/TLR4 play critical roles in MTS growth. They also prevented MTS culture-induced Snail expression, pointing to RAGE/TLR2/TLR4-dependent Snail expression. RAGE, TLR2, and TLR4 shRNA suppressed the MTS-induced EMT. In human cancer tissues, high levels of RAGE, TLR2, and TLR4 were detected. These findings demonstrated that the HMGB-RAGE/TLR2/TLR4-Snail axis played a crucial role in the growth of the MTS and MTS culture-induced EMT.

• Journal of Ginseng Research
• /
• v.43 no.1
• /
• pp.68-76
• /
• 2019

Background: In colorectal cancer (CRC), 40-60% of patients develop metastasis. The epithelial-mesenchymal transition (EMT) is a pivotal and intricate process that increases the metastatic potential of CRC. The aim of this study was to investigate the effect of Korean Red Ginseng extract (RGE) on colorectal metastasis through inhibition of EMT and the metastatic abilities of CRC cells. Methods: To investigate the effect of RGE on the metastatic phenotypes of CRC cells, CT26 and HT29 cells were evaluated by using an adhesion assay, a wound-healing assay, an invasion assay, zymography, and real-time reverse transcription-polymerase chain reaction. Western-blot analysis was conducted to elucidate the molecular mechanisms of RGE, which showed an inhibitory effect on the transforming growth factor-${\beta}1$ ($TGF-{\beta}1$)-induced EMT in HT29 cells. Additionally, the antimetastatic effect of RGE was evaluated in a mouse model of lung metastasis injected with CT26 cells. Results: RGE decreased the adhesion and migration ability of the CT26 cells and TGF-${\beta}1$-treated HT29 cells. The invasion ability was also reduced by RGE treatment through the inhibition of matrix metalloproteinase-9 expression and activity. Moreover, RGE suppressed the TGF-${\beta}1$-induced EMT via TGF-${\beta}1$/Smad-signaling-mediated Snail/E-cadherin expression in HT29 cells and lung tissue in CT26 tumor-bearing mice. Conclusion: Our results demonstrated that RGE inhibited colorectal lung metastasis through a reduction in metastatic phenotypes, such as migration, invasion, and the EMT of CRC cells.

• Journal of The Korean Society of Integrative Medicine
• /
• v.11 no.3
• /
• pp.59-67
• /
• 2023

Purpose : Epithelial-to-mesenchymal transition (EMT) is recognized as an important cellular response in metastatic proceduresand characterized by loss of cellular polarity as well as gain of mesenchymal features, which enables migration and invasion. Hepatocellular carcinoma (HCC) is one of the most common primary carcinomas in the liver and exhibits a poor prognosis due to frequent extrahepatic metastasis. Taraxacum officinale has been used for a long time in oriental medicine because of its various pharmacological activitiessuch as anti-rheumatic, anti-inflammatory, antioxidative, and anticarcinogenic activities. In this study, the anti-metastatic activity of T. officinale water extract (TOWE) and ethanol extract (TOEE) was investigated through the regulation of EMT in the Huh7 cells. Methods : The effects of TOWE and TOEE on migratory and invasive activities were investigated by wound healing and in vitro invasion assays. Western blot analysis was also applied to analyze protein expression levels associated with EMT and their upstream transcription factors in Huh7 cells. Results : TOWE and TOEE treatment potently inhibited migration and invasion of Huh7 cells compared to the untreated group. Both extracts treatment inhibited protein expression levels of N-cadherin, matrix metalloproteinase (MMP)-9, and vimentin while E-cadherin was significantly accelerated. In addition, the activated status of transcription factors, Snail, nuclear factor (NF)-κ B, and zinc finger E-box binding homeobox (ZEB)1 was also inhibited with statistical significance. In comparison to both extracts, TOEE more potently attenuated migration, invasion, and EMT markers as well as their transcription factors in Huh7 cells than TOWE, which means that TOEE might possess more functional phytochemicals than TOWE. Conclusion : Consequently, TOWE and TOEEattenuated metastatic activity of hepatocellular carcinoma through the regulation of EMT markers and their transcription factors in Huh7 cells, which means that T. officinale might be a promising strategy for a chemopreventive agent against HCC metastasis.