• Toxicological Research
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• v.27 no.4
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• pp.253-259
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• 2011

Transforming growth factor ${\beta}$ (TGF-${\beta}$) is involved in cellular processes including growth, differentiation, apoptosis, migration, and homeostasis. Generally, TGF-${\beta}$ is the inhibitor of cell cycle progression and plays a role in enhancing the antagonistic effects of many growth factors. Unlike the antiproliferative effect of TGF-${\beta}$, E2, an endogeneous estrogen, is stimulating cell proliferation in the estrogen-dependent organs, which are mediated via the estrogen receptors, $ER{\alpha}$ and $ER{\beta}$, and may be considered as a critical risk factor in tumorigenesis of hormone-responsive cancers. Previous researches reported the cross-talk between estrogen/$ER{\alpha}$ and TGF-${\beta}$ pathway. Especially, based on the E2-mediated inhibition of TGF-${\beta}$ signaling, we examined the inhibition effect of 4-tert-octylphenol (OP) and 4-nonylphenol (NP), which are well known xenoestrogens in endocrine disrupting chemicals (EDCs), on TGF-${\beta}$ signaling via semi-quantitative reverse-transcription PCR. The treatment of E2, OP, or NP resulted in the downregulation of TGF-${\beta}$ receptor2 (TGF-${\beta}$ R2) in TGF-${\beta}$ signaling pathway. However, the expression level of TGF-${\beta}1$ and TGF-${\beta}$ receptor1 (TGF-${\beta}$ R1) genes was not altered. On the other hand, E2, OP, or NP upregulated the expression of a cell-cycle regulating gene, c-myc, which is a oncogene and a downstream target gene of TGF-${\beta}$ signaling pathway. As a result of downregulation of TGF-${\beta}$ R2 and the upregulation of c-myc, E2, OP, or NP increased cell proliferation of BG-1 ovarian cancer cells. Taken together, these results suggest that E2 and these two EDCs may mediate cancer cell proliferation by inhibiting TGF-${\beta}$ signaling via the downregulation of TGF-${\beta}$ R2 and the upregulation of c-myc oncogene. In addition, it can be inferred that these EDCs have the possibility of tumorigenesis in estrogen-responsive organs by certainly representing estrogenic effect in inhibiting TGF-${\beta}$ signaling.

• Proceedings of the PSK Conference
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• 2003.10b
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• pp.152.2-153
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• 2003

${\beta}Although$ it has been demonstrated that $p2l^{WAFl/Cip1}$, a well known cell cycle inhibitor, could be induced by $TGF-{\beta}$ in a p53-independent manner, the detailed signal transduction pathways still remain poorly understood. In this study, we show that ERK is required for $TGF-{\beta}$ induction of $p21^{WAF1/Cip1}$, but JNK or p38 MAPK is not. ERK activation by $TGF-{\beta}$ significantly attenuated by treatment with ROS scavenger such as NAC or catalase, indicating that ROS, mainly $H_2O_2$, generation by $TGF-{\beta}$ might stimulate ERK signaling pathway to require the induction of $p21^{WAF1/Cip1}$. (omitted)

• Herbal Formula Science
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• v.26 no.3
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• pp.183-193
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• 2018

Objectives : In Traditional Korean Medicine, Epimedium koreanum Nakai has diverse pharmacological activities to treat impotence, forgetfulness, cataract and exophthalmos. Present study investigated anti-fibrogenic effects of E. koreanum water extract (EKE) in hepatic stellate cells (HSCs). Methods : To study anti-fibrogenic effects of EKE, LX-2 cells, a human immortalized HSCs, were pre-treated with $3-300{\mu}g/mL$ of EKE, and then subsequently exposed to 5 ng/mL of transforming growth $factor-{\beta}1$ ($TGF-{\beta}1$). Expression level of ${\alpha}-smooth$ muscle actin was determined by immunoblot analysis. Phosphorylation of Smad, transactivation of Smad, and expression of plasminogen activator inhibitor-1 (PAI-1) were monitored to investigate the effect of EKE on $TGF-{\beta}1-mediated$ signaling pathway. Results : Up to $100{\mu}g/mL$, EKE did not show any cytotoxicity on LX-2 cells. Pre-treatment of EKE ($100{\mu}g/mL$) significantly inhibited ${\alpha}-smooth$ muscle actin expression induced by $TGF-{\beta}1$. In addition, EKE significantly decreased Smad2 and Smad3 phosphorylations, Smad binding element-driven luciferase activity and PAI-1 expression by $TGF-{\beta}1$. Of three flavonoid compounds found in EKE, only quercertin ($30{\mu}M$) attenuated $TGF-{\beta}1-mediated$ PAI-1 expression. Conclusion : These results suggest that EKE has an ability to suppress fibrogenic process in HSCs via inhibition of $TGF-{\beta}1/Smad$ signaling pathway.

• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.211-223
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• 2017

Transforming growth factor beta ($TGF-{\beta}$) signaling pathways are involved in the regulation of proliferation, differentiation, immunity, survival, and apoptosis of many cells. The aim of this study was to investigate the differential expression of $TGF-{\beta}$-related genes, and their interactions and regulators in the spleen of two genetically disparate chicken lines (Marek's disease resistant line 6.3 and Marek's disease-susceptible line 7.2) induced with necrotic enteritis (NE) by Eimeria maxima and Clostridium perfringens infection. By using high-throughput RNA-sequencing, we investigated 76 $TGF-{\beta}$-related genes that were significantly and differentially expressed in the spleens of the chickens. Approximately 20 $TGF-{\beta}$ pathway genes were further verified by qRT-PCR, and the results were consistent with our RNA sequencing data. All 76 identified genes were analyzed through Gene Ontology and mapped onto the KEGG chicken $TGF-{\beta}$ pathway. Our results demonstrated that several key genes, including $TGF-{\beta}$1-3, bone morphogenetic proteins (BMP)1-7, inhibitor of differentiation (ID) proteins ID1-3, SMAD1-9, and Jun, showed a markedly differential expression between the two chicken lines, relative to their respective controls. We then further predicted 24 known miRNAs that targeted BMP7 mRNA from 139 known miRNAs in the two chicken lines. Among these, six miRNAs were measured by qRT-PCR. In conclusion, this study is the first to analyze most of the genes, interactions, and regulators of the $TGF-{\beta}$ pathway in the innate immune responses of NE afflicted chickens.

• Asian-Australasian Journal of Animal Sciences
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• v.25 no.3
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• pp.304-310
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• 2012

The present study showed that Transforming growth factor beta 1 (TGF-${\beta}_1$) can induce apoptosis of bovine mammary epithelial cells. This apoptosis was also observed with phosphorylation of Smad2/3 within 0.5-2 h. Afterwards the signal transferred into the nucleus. Moreover, intracellular free $Ca^{2+}$ concentration was significantly elevated as well as Caspase-3 activated and DNA lysised, thereby inducing the programmed cell death. This signaling pathway of TGF-${\beta}_1$ was blocked by SB-431542 ($10^{-2}{\mu}M$) via inhibiting ALK-5 kinase activity, which thus reversed the anti-proliferation and apoptosis effect of TGF-${\beta}_1$ in mammary epithelial cells. These results indicated that TGF-${\beta}_1$ induced apoptosis of bovine mammary epithelial cells through the ALK-5-Smad2/3 pathway, which plays an important role in inhibiting survival of mammary epithelial cells. Moreover, intracellular $Ca^{2+}$ also played a critical role in TGF-${\beta}_1$-induced cell apoptosis.

• BMB Reports
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• v.55 no.8
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• pp.401-406
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• 2022

Ahnak, a large protein first identified as an inhibitor of TGF-β signaling in human neuroblastoma, was recently shown to promote TGF-β in some cancers. The TGF-β signaling pathway regulates cell growth, various biological functions, and cancer growth and metastasis. In this study, we used Ahnak knockout (KO) mice that underwent a 70% partial hepatectomy (PH) to investigate the function of Ahnak in TGF-β signaling during liver regeneration. At the indicated time points after PH, we analyzed the mRNA and protein expression of the TGF -β/Smad signaling pathway and cell cycle-related factors, evaluated the cell cycle through proliferating cell nuclear antigen (PCNA) immunostaining, analyzed the mitotic index by hematoxylin and eosin staining. We also measured the ratio of liver tissue weight to body weight. Activation of TGF-β signaling was confirmed by analyzing the levels of phospho-Smad 2 and 3 in the liver at the indicated time points after PH and was lower in Ahnak KO mice than in WT mice. The expression levels of cyclin B1, D1, and E1; proteins in the Rb/E2F transcriptional pathway, which regulates the cell cycle; and the numbers of PCNA-positive cells were increased in Ahnak KO mice and showed tendencies opposite that of TGF-β expression. During postoperative regeneration, the liver weight to body weight ratio tended to increase faster in Ahnak KO mice. However, 7 days after PH, both groups of mice showed similar rates of regeneration, following which their active regeneration stopped. Analysis of hepatocytes undergoing mitosis showed that there were more mitotic cells in Ahnak KO mice, consistent with the weight ratio. Our findings suggest that Ahnak enhances TGF-β signaling during postoperative liver regeneration, resulting in cell cycle disruption; this highlights a novel role of Ahnak in liver regeneration. These results provide new insight into liver regeneration and potential treatment targets for liver diseases that require surgical treatment.

• Molecules and Cells
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• v.40 no.3
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• pp.211-221
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• 2017

Transforming growth factor ${\beta}1$ $(TGF{\beta}1)/Smad4$ signaling plays a pivotal role in maintenance of the dynamic balance between bone formation and resorption. The microRNA miR-155 has been reported to exert a significant role in the differentiation of macrophage and dendritic cells. The goal of this study was to determine whether miR-155 regulates osteoclast differentiation through $TGF{\beta}1/Smad4$ signaling. Here, we present that $TGF{\beta}1$ elevated miR-155 levels during osteoclast differentiation through the stimulation of M-CSF and RANKL. Additionally, we found that silencing Smad4 attenuated the upregulation of miR-155 induced by $TGF{\beta}1$. The results of luciferase reporter experiments and ChIP assays demonstrated that $TGF{\beta}1$ promoted the binding of Smad4 to the miR-155 promoter at a site located in 454 bp from the transcription start site in vivo, further verifying that miR-155 is a transcriptional target of the $TGF{\beta}1/Smad4$ pathway. Subsequently, TRAP staining and qRT-PCR analysis revealed that silencing Smad4 impaired the $TGF{\beta}1$-mediated inhibition on osteoclast differentiation. Finally, we found that miR-155 may target SOCS1 and MITF to suppress osteoclast differentiation. Taken together, we provide the first evidence that $TGF{\beta}1/Smad4$ signaling affects osteoclast differentiation by regulation of miR-155 expression and the use of miR-155 as a potential therapeutic target for osteoclast-related diseases shows great promise.

• The Journal of Internal Korean Medicine
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• v.26 no.1
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• pp.93-106
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• 2005

Objectives : The aim of this study is to characterize the effect of Chungganhaeju-tang on $TGF-{\beta}l$-induced hepatic fibrosis. Materials and Methods : mRNA and protein expression levels of $TGF-{\beta}l$ in Chungganhaeju-tang treated HepG2 cells were compared to untreated cells using quantitative RT-PCR and ELISA assay, respectively. mRNA expression levels of the $TGF-{\beta}l$ signaling pathway genes $(T{\beta}R-I,\;T{\beta}R-II,\;Smad2,\;Smad3,\;Smad4,\;and\;PAI-1)$ and fibrosis-associated genes (CTGF, fibronectin, and collagen type $l{\alpha}$) were evaluated by quantitative RT-PCR. The effect of Chungganhaeju-tang on cell proliferation of T3891 human fibroblast was evaluated using $[^3H]Thymidine$ Incorporation Assay. Results : Inhibition of $TGF-{\beta}l$ mRNA expression and protein production was observed with treatment of Chungganhaeju-tang and seen to be dose and time dependent. Whereas $TGF-{\beta}l$-mediated induction of PAI-1 was suppressed with treatment of Chungganhaeju-tang, expression of the $TGF-{\beta}l$ signaling pathway genes such as $T{\beta}R-I$, $T{\beta}R-II$, Smad2, Smad3, and Smad4 was not affected. With treatment of Chungganhaeju-tang, inhibition of $TGF-{\beta}l$-induced cell proliferation of T3891 human fibroblast was observed, as well as abrogation of $TGF-{\beta}l$-mediated transcriptional up-regulation of CTGF, fibronectin, and collagen type $I{\alpha}$. Conclusion : This study strongly suggests that the liver cirrhosis-suppressive activity of Chungganhaeju-tang may be derived at least in part from its inhibitory effect on $TGF-{\beta}l$ functions, such as blockade of $TGF-{\beta}l$ stimulation of fibroblast cell proliferation and fibrosis-related gene expression as well as expression of $TGF-{\beta}l$ itself.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.273-276
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• 2014

Ellagic acid has been shown to inhibit tumor cell growth. However, the underlying molecular mechanisms remain elusive. In this study, our aim was to investigate whether ellagic acid inhibits the proliferation of MCF-7 human breast cancer cells via regulation of the TGF-${\beta}$/Smad3 signaling pathway. MCF-7 breast cancer cells were transfected with pEGFP-C3 or pEGFP-C3/Smad3 plasmids, and treated with ellagic acid alone or in combination with SIS3, a specific inhibitor of Smad3 phosphorylation. Cell proliferation was assessed by MTT assay and the cell cycle was detected by flow cytometry. Moreover, gene expression was detected by RT-PCR, real-time PCR and Western blot analysis. The MTT assay showed that SIS3 attenuated the inhibitory activity of ellagic acid on the proliferation of MCF-7 cells. Flow cytometry revealed that ellagic acid induced G0/G1 cell cycle arrest which was mitigated by SIS3. Moreover, SIS3 reversed the effects of ellagic acid on the expression of downstream targets of the TGF-${\beta}$/Smad3 pathway. In conclusion, ellagic acid leads to decreased phosphorylation of RB proteins mainly through modulation of the TGF-${\beta}$/Smad3 pathway, and thereby inhibits the proliferation of MCF-7 breast cancer cells.

• Molecules and Cells
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• v.24 no.3
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• pp.431-436
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• 2007

Stem cell-based therapy is being considered as an alternative treatment for cardiomyopathy. Hence understanding the basic molecular mechanisms of cardiomyocyte differentiation is important. Besides BMP or Wnt family proteins, $TGF-{\beta}$ family members are thought to play a role in cardiac development and differentiation. Although $TGF-{\beta}$ has been reported to induce cardiac differentiation in embryonic stem cells, the differential role of $TGF-{\beta}$ isoforms has not been elucidated. In this study, employing the DMSO-induced cardiomyocyte differentiation system using P19CL6 mouse embryonic teratocarcinoma stem cells, we investigated the $TGF-{\beta}$-induced signaling pathway in cardiomyocyte differentiation. $TGF-{\beta}1$, but not the other two isoforms of $TGF-{\beta}$, was induced at the mRNA and protein level at an early stage of differentiation, and Smad2 phosphorylation increased in parallel with $TGF-{\beta}1$ induction. Inhibition of $TGF-{\beta}1$ activity with $TGF-{\beta}1$-specific neutralizing antibody reduced cell cycle arrest as well as expression of the CDK inhibitor $p21^{WAF1}$. The antibody also inhibited induction of the cardiac transcription factor Nkx2.5. Taken together, these results suggest that $TGF-{\beta}1$ is involved in cardiomyocyte differentiation by regulating cell cycle progression and cardiac gene expression in an autocrine or paracrine manner.