SMAD2

Gene Summary

Gene:SMAD2; SMAD family member 2
Aliases: JV18, MADH2, MADR2, JV18-1, hMAD-2, hSMAD2
Location:18q21.1
Summary:The protein encoded by this gene belongs to the SMAD, a family of proteins similar to the gene products of the Drosophila gene 'mothers against decapentaplegic' (Mad) and the C. elegans gene Sma. SMAD proteins are signal transducers and transcriptional modulators that mediate multiple signaling pathways. This protein mediates the signal of the transforming growth factor (TGF)-beta, and thus regulates multiple cellular processes, such as cell proliferation, apoptosis, and differentiation. This protein is recruited to the TGF-beta receptors through its interaction with the SMAD anchor for receptor activation (SARA) protein. In response to TGF-beta signal, this protein is phosphorylated by the TGF-beta receptors. The phosphorylation induces the dissociation of this protein with SARA and the association with the family member SMAD4. The association with SMAD4 is important for the translocation of this protein into the nucleus, where it binds to target promoters and forms a transcription repressor complex with other cofactors. This protein can also be phosphorylated by activin type 1 receptor kinase, and mediates the signal from the activin. Alternatively spliced transcript variants have been observed for this gene. [provided by RefSeq, May 2012]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:mothers against decapentaplegic homolog 2
Source:NCBIAccessed: 11 March, 2017

Ontology:

What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1992-2017)
Graph generated 11 March 2017 using data from PubMed using criteria.

Literature Analysis

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Tag cloud generated 11 March, 2017 using data from PubMed, MeSH and CancerIndex

Specific Cancers (7)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: SMAD2 (cancer-related)

Lv XQ, Qiao XR, Su L, Chen SZ
Honokiol inhibits EMT-mediated motility and migration of human non-small cell lung cancer cells in vitro by targeting c-FLIP.
Acta Pharmacol Sin. 2016; 37(12):1574-1586 [PubMed] Free Access to Full Article Related Publications
AIM: Honokiol (HNK) is a natural compound isolated from the magnolia plant with numerous pharmacological activities, including inhibiting epithelial-mesenchymal transition (EMT), which has been proposed as an attractive target for anti-tumor drugs to prevent tumor migration. In this study we investigated the effects of HNK on EMT in human NSCLC cells in vitro and the related signaling mechanisms.
METHODS: TNF-α (25 ng/mL) in combination with TGF-β1 (5 ng/mL) was used to stimulate EMT of human NSCLC A549 and H460 cells. Cell proliferation was analyzed using a sulforhodamine B assay. A wound-healing assay and a transwell assay were performed to examine cell motility. Western blotting was used to detect the expression levels of relevant proteins. siRNAs were used to knock down the gene expression of c-FLIP and N-cadherin. Stable overexpression of c-FLIP L (H157-FLIP L) or Lac Z (H157-Lac Z) was also performed.
RESULTS: Treatment with TNF-α+TGF-β1 significantly enhanced the migration of A549 and H460 cells, increased c-FLIP, N-cadherin (a mesenchymal marker), snail (a transcriptional modulator) and p-Smad2/3 expression, and decreased IκB levels in the cells; these changes were abrogated by co-treatment with HNK (30 μmol/L). Further studies demonstrated that expression level of c-FLIP was highly correlated with the movement and migration of NSCLC cells, and the downstream effectors of c-FLIP signaling were NF-κB signaling and N-cadherin/snail signaling, while Smad signaling might lie upstream of c-FLIP.
CONCLUSION: HNK inhibits EMT-mediated motility and migration of human NSCLC cells in vitro by targeting c-FLIP, which can be utilized as a promising target for cancer therapy, while HNK may become a potential anti-metastasis drug or lead compound.

Wu Q, Wang X, Liu J, et al.
Nutlin-3 reverses the epithelial-mesenchymal transition in gemcitabine-resistant hepatocellular carcinoma cells.
Oncol Rep. 2016; 36(3):1325-32 [PubMed] Related Publications
Nutlin-3, a small molecule regulator of the tumor suppressor p53, targets the interaction between p53 and murine double minute 2 (MDM2) thereby promoting stabilization of p53 and subsequent p53‑dependent induction of apoptosis and cell cycle arrest. Recent studies have demonstrated that Nutlin‑3 plays a critical role in regulating tumor cell migration, invasion, metastasis, and drug resistance. Although these studies identified various biological functions of Nutlin‑3, our understanding of the exact molecular mechanisms of Nutlin‑3‑mediated antitumor activity remains incomplete. In this study, we elucidated a role of Nutlin‑3 in reversing the epithelial‑mesenchymal transition (EMT) in gemcitabine-resistant (GR) hepatocellular carcinoma (HCC) cells. We assessed the effect of Nutlin‑3 treatment on cell growth, migration, and invasion in both parental HCC cells and GR HCC cells. Moreover, we detected the expression of EMT markers in GR HCC cells treated with Nutlin‑3 by real‑time RT‑PCR and western blot analysis, respectively. We found that Nutlin-3 inhibited cell migration and invasion in the GR HCC cells. Additionally, Nutlin‑3 treatment increased E-cadherin protein levels, but decreased the protein levels of vimentin, Snail and Slug in the GR HCC cells. Furthermore, we found that Smad2 was highly expressed in the GR HCC cells compared with their parental HCC cells, and Nutlin-3 treatment downregulated Smad2 expression in the GR HCC cells. Depletion of Smad2 retarded cell migration and regulated the expression of EMT markers in GR HCC cells similarly to Nutlin‑3 treatment. Our findings highlight an important role of Nutlin‑3 in reversing EMT in GR cells through regulation of Smad2 expression, suggesting that Nutlin-3 could be a potential agent for the treatment of HCC patients with gemcitabine resistance.

Zhou Q, Zheng X, Chen L, et al.
Smad2/3/4 Pathway Contributes to TGF-β-Induced MiRNA-181b Expression to Promote Gastric Cancer Metastasis by Targeting Timp3.
Cell Physiol Biochem. 2016; 39(2):453-66 [PubMed] Related Publications
BACKGROUND/AIMS: Transforming growth factor beta (TGF-β) plays a major role in tumorigenesis. MicroRNA-181b (miRNA-181b) is a multifaceted miRNA that has been implicated in many cellular processes such as cell fate determination and cellular invasion. This study aimed to confirm the relationship of miRNA-181b and the TGF-β-Smad2/3/4 pathway with the induction of the epithelial-to-mesenchymal transition (EMT) in gastric cancer.
METHODS: This study investigated the ability of TGF-β to induce migration by wound healing and transwell invasion assays in human gastric cancer cell lines. miRNA expression was altered using miRNA-181b mimic and inhibitor in the same system. Expression of miRNA-181b, the hypothetical target gene Timp3 and EMT-related markers were analyzed by real-time real-time quantitative RT-PCR. Immunoblotting was used to investigate the levels of phospho-Smad2 and Smad4. Dual-luciferase reporter assays were performed to confirm the direct binding of miRNA-181b to Timp3.
RESULTS: miRNA-181b was significantly upregulated in response to TGF-β treatment in gastric cancer cell lines. Overexpression of miR-181b mimic induced an in vitro EMT-like change to a phenotype similar to that following TGF-β treatment alone and was reversed by miRNA-181b inhibitor. Inhibition of TGF-β-Smad2/3 signaling with SD-208 significantly attenuated the upregulation of miRNA-181b. Knockdown of Smad4 in gastric cancer cells strongly attenuated the upregulation of miRNA-181b. Moreover, miR-181b was found to directly target the 3' untranslated region (3'UTR) of Timp3 mRNA affecting TGF-β-induced EMT.
CONCLUSIONS: Our results elucidate a novel mechanism through which the TGF-β pathway regulates the EMT of gastric cancer cells by increasing the levels of miRNA-181b to target Timp3 via the Smad2/3/4-dependent pathway. These findings provide insights into the cellular and environmental factors regulating EMT, which may guide future studies on therapeutic strategies targeting these cells.

Fang L, Zhao J, Wang D, et al.
Jumonji AT-rich interactive domain 1B overexpression is associated with the development and progression of glioma.
Int J Mol Med. 2016; 38(1):172-82 [PubMed] Free Access to Full Article Related Publications
Previous studies have suggested that jumonji AT-rich interactive domain 1B (JARID1B) plays an important role in the genesis of some types of cancer, and it is therefore considered to be an important drug target protein. Although the expression of JARID1B has been researched in some types of cancer, little is known about JARID1B expression in glioma and its function in the tumorigenesis of gliomas. In the present study, we examined the expression of JARID1B in glioma. In addition, RT-PCR, western blot analysis and immunohistochemical analysis were performed using glioma tissue samples and the results revealed that JARID1B expression increased according to the histological grade of glioma. However, in the normal brain tissue samples JARID1B expression was barely detected. Kaplan‑Meier analysis revealed that higher JARID1B expression in patients with glioma was associated with a poorer prognosis. The overexpression of JARID1B stimulated the proliferation and migration of glioma cells as well as sphere formation, whereas suppressing the expression of JARID1B produced opposite effects. The overexpression of JARID1B increased the tumorigenicity of glioma cells in vivo in a nude mouse xenograft model of glioma. Moreover, the activation of phosphorylated (p-)Smad2 contributes to JARID1B-induced oncogenic activities. These findings suggest that JARID1B is involved in the pathogenesis of glioma, and that the downregulation of JARID1B in glioma cells may be a therapeutic target for the treatment of patients with glioma.

Qu Z, Li D, Xu H, et al.
 CUL4B, NEDD4, and UGT1As involve in the TGF-β signalling in hepatocellular carcinoma.
Ann Hepatol. 2016 Jul-Aug; 15(4):568-76 [PubMed] Related Publications
UNLABELLED:  Introduction and Aim. TGF-β signalling is involved in pathogenesis and progress of hepatocellular carcinoma (HCC). This bioinformatics study consequently aims to determine the underlying molecular mechanism of TGF- β activation in HCC cells.
MATERIAL AND METHODS: Dataset GSE10393 was downloaded from Gene Expression Omnibus, including 2 Huh-7 (HCC cell line) samples treated by TGF- β (100 pmol/L, 48 h) and 2 untreated samples. Differentially expressed genes (DEGs) were screened using Limma package (false discovery rate < 0.05 and |log2 fold change| > 1.5), and then enrichment analyses of function, pathway, and disease were performed. In addition, protein-protein interaction (PPI) network was constructed based on the PPI data from multiple databases including INACT, MINT, BioGRID, UniProt, BIND, BindingDB, and SPIKE databases. Transcription factor (TF)-DEG pairs (Bonferroni adjusted p-value < 0.01) from ChEA database and DEG-DEG pairs were used to construct TF-DEG regulatory network. Furthermore, TF-pathway-DEG complex network was constructed by integrating DEG-DEG pairs, TF-DEG pairs, and DEG-pathway pairs.
RESULTS: Totally, 209 DEGs and 30 TFs were identified. The DEGs were significantly enriched in adhesion-related functions. PPI network indicted hub genes such as CUL4B and NEDD4. According to the TF-DEG regulatory network, the two hub genes were targeted by SMAD2, SMAD3, and HNF4A. Besides, the 11 pathways in TF-pathway-DEG network were mainly enriched by UGT1A family and CYP3A7, which were predicted to be regulated by SMAD2, SMAD3, SOX2, TP63, and HNF4A.
CONCLUSIONS: TGF- β might influence biological processes of HCC cells via SMAD2/SMAD3-NEDD4, HNF4A-CUL4B/NEDD4, SOX2/TP63/HNF4A-CYP3A7, and SMAD2/SMAD3/SOX2/TP63/HNF4A-UGT1As regulatory pathways.

Lin SH, Wang BY, Lin CH, et al.
Chidamide alleviates TGF-β-induced epithelial-mesenchymal transition in lung cancer cell lines.
Mol Biol Rep. 2016; 43(7):687-95 [PubMed] Related Publications
Transforming growth factor-β (TGF-β)-induced epithelial-mesenchymal transition is a critical process in the initiation of metastasis of various types of cancer. Chidamide is a class I histone deacetylase inhibitor with anti-tumor activity. This study investigated the effects of chidamide on TGF-β-mediated suppression of E-cadherin expression in adenocarcinomic lung epithelial cells and the molecular mechanisms involved in these effects. Western blot analysis, confocal microscopy, Quantitative methyl-specific PCR and bisulfite sequencing were used to evaluate the effects of different treatments on chidamide ameliorating TGF-β induced-E-cadherin loss. H3 acetylation binding to the promoter of E-cadherin was detected by chromatin immunoprecipitations (CHIP). We found that chidamide reduced the level of lung cancer cell migration observed using a Boyden chamber assay (as an indicator of metastatic potential). Chidamide inhibited TGF-β-induced SMAD2 phosphorylation and attenuated TGF-β-induced loss of E-cadherin expression in lung cancer cells by Western blotting and confocal microscopy, respectively. Quantitative methyl-specific PCR and bisulfite sequencing revealed that TGF-β-enhanced E-cadherin promoter methylation was ameliorated in cells treated with chidamide. We demonstrated that histone H3 deacetylation within the E-cadherin promoter was required for TGF-β-induced E-cadherin loss; cell treatment with chidamide increased the H3 acetylation detected by CHIP. Taken together, our results demonstrate that TGF-β suppressed E-cadherin expression by regulating promoter methylation and histone H3 acetylation. Chidamide significantly enhanced E-cadherin expression in TGF-β-treated cells and inhibited lung cancer cell migration. These findings indicate that chidamide has a potential therapeutic use due to its capacity to prevent cancer cell metastasis.

Wu Y, Liu Q, Yan X, et al.
Podoplanin-mediated TGF-β-induced epithelial-mesenchymal transition and its correlation with bHLH transcription factor DEC in TE-11 cells.
Int J Oncol. 2016; 48(6):2310-20 [PubMed] Free Access to Full Article Related Publications
Podoplanin is reported involved in the collective cell invasion, another tumor invasion style which is distinct from the single cell invasion, so-called epithelial-mesenchymal transition (EMT). In this study, we investigated the correlation between podoplanin and EMT-related markers in esophageal squamous cell carcinoma (ESCC), and evaluated its linkage with the basic helix-loop-helix (bHLH) transcription factor differentiated embryonic chondrocyte (DEC) 1 and DEC2. Three ESCC cell lines and human squamous cell carcinoma A431 cells were subjected to western blot analyses for podoplanin and EMT markers, as well as the expression of DEC1 and DEC2. By RT-qPCR and western blotting, we found that TGF-β increased the expression of podoplanin and mensenchymal markers (e.g., N-cadherin and vimentin), while decreased the expression of epithelial markers (e.g., Claudin-4 and E-cadherin), accompanied by Smad2 phosphorylation and slug activation. Moreover, TGF-β has different effects on the expression of DEC1 and DEC2, that is, it upregulates DEC1, but downregulates DEC2. Capability of cell proliferation, invasion and migration were further analyzed using CCK-8 assay, Matrigel-invasion assay, and the wound-healing assay, respectively. The proliferation, invasion and migration ability were significantly lost in podoplanin-knockdown cells when compared with the scrambled siRNA group. In addition to these changes, the expression of Claudin-4, but not that of Claudin-1 or E-cadherin, was induced by the siRNA against podoplanin. On the contrary, overexpression of DEC1 and DEC2 exhibits opposite effects on podoplanin, but only slight effect on Claudin-4 was detected. These data indicated that podoplanin is significantly associated with EMT of TE-11 cells, and may be directly or indirectly regulated by bHLH transcription factors DEC1 and DEC2.

Zhang W, Li Y
miR-148a downregulates the expression of transforming growth factor-β2 and SMAD2 in gastric cancer.
Int J Oncol. 2016; 48(5):1877-85 [PubMed] Free Access to Full Article Related Publications
The effects of miR-148a in regulating the expression of TGFβ2 and SMAD2 in MNNG-initiated gastric cancer rats and the mechanism of action in GC cells were determined. Effects of miR-148a on the proliferation, migration, and invasion of GC cell lines were demonstrated. We used Wistar rats, Balb/c nude mice, and GC cell lines. Rats were treated with MNNG to establish a GC rat model. Levels of miR-148a, TGFα, TGFβ2, SMAD2, SMAD3, and SMAD4 were tested in gastric tissues from different groups. In GC cell lines, we constructed and transfected a primary miR-148a plasmid to determine the expression patterns of TGFβ2, SMAD2, and SMAD4. A luciferase activity assay was used to monitor the effects of miR-148a on the TGFβ2- and SMAD2-3'UTRs. We identified nude mouse models bearing BGC-823-miR-148a or BGC-823-vector cells. Tumor volumes were detected, and TGFβ2, SMAD2 expression levels were determined in tumor tissues. The in vivo study demonstrated an increase in the mRNA and protein levels of TGFβ2, SMAD2, and SMAD4 in the MNNG-treated group compared with the control group. However, there were no differences in the mRNA and protein levels in either TGFα or SMAD3. The in vitro study demonstrated that overexpression of miR-148a reduced TGFβ2 and SMAD2 significantly in GC cells. The results of the luciferase activity assay showed that miR-148a could bind to the 3'UTRs of TGFβ2 and SMAD2 and inhibited their activity. Overexpression of miR-148a inhibited proliferation, migration, and invasion significantly in GC cell lines. In vivo, tumor volume of BGC-823-miR-148a was smaller than that of BGC-823-vector. Overall, miR-148a inhibited the proliferation, migration, invasion, and expression of TGFβ2 and SMAD2 in GC cells. It was concluded that miR-148a might play an important role in gastric cancer, and is a potential candidate for GC treatment.

Yu S, Yan C, Yang X, et al.
Pharmacoproteomic analysis reveals that metapristone (RU486 metabolite) intervenes E-cadherin and vimentin to realize cancer metastasis chemoprevention.
Sci Rep. 2016; 6:22388 [PubMed] Free Access to Full Article Related Publications
Metapristone is the most predominant biological active metabolite of mifepristone, and being developed as a novel cancer metastasis chemopreventive agent by us. Despite its prominent metastasis chemopreventive effect, the underlying mechanism remains elusive. Our study, for the first time, demonstrated that metapristone had the ability to prevent breast cancer cells from migration, invasion, and interfere with their adhesion to endothelial cells. To explore the underlying mechanism of metapristone, we employed the iTRAQ technique to assess the effect of metapristone on MDA-MB-231 cells. In total, 5,145 proteins were identified, of which, 311 proteins showed significant differences in metapristone-treated cells compared to the control group (P-value < 0.05). Bioinformatic analysis showed many differentially expressed proteins (DEPs) functionally associated with post-translational modification, chaperones, translation, transcription, replication, signal transduction, etc. Importantly, many of the DEPs, such as E-cadherin, vimentin, TGF-β receptor I/II, smad2/3, β-catenin, caveolin, and dystroglycan were associated with TGF-β and Wnt signaling pathways, which were also linked to epithelial-to-mesenchymal transition (EMT) process. Further validation of the epithelial marker "E-caderin" and mesenchymal marker "vimetin" were carried out using immunoblot and immunofluorescence. These results have revealed a novel mechanism that metapristone-mediated metastasis chemoprevention is through intervening the EMT-related signaling pathways.

Park SJ, Lee BR, Kim HS, et al.
Inhibition of Migration and Invasion by Tet-1 Overexpression in Human Lung Carcinoma H460 Cells.
Oncol Res. 2016; 23(3):89-98 [PubMed] Related Publications
In the present study, we found that lung cancer cell line (H460 cells) expressing Tet1 showed higher levels of adhesion, and Tet1 inhibited H460 cell proliferation. In addition, these cells showed a significantly reduced ability of collagen degradation and Smad2/3 phosphorylation compared to controls. Furthermore, vimentin was found to be highly expressed in larger metastatic cancer area. Tet1 overexpression was reduced in the epithelial marker E-cadherin. Moreover, Tet1 repressed cancer cell metastasis in nude mice. Collectively, these findings suggest that Tet1 expression plays a critical role in metastasis of lung cancer cells by suppression of invasion and epithelial-mesenchymal transition (EMT).

Wahdan-Alaswad R, Harrell JC, Fan Z, et al.
Metformin attenuates transforming growth factor beta (TGF-β) mediated oncogenesis in mesenchymal stem-like/claudin-low triple negative breast cancer.
Cell Cycle. 2016; 15(8):1046-59 [PubMed] Free Access to Full Article Related Publications
Mesenchymal stem-like/claudin-low (MSL/CL) breast cancers are highly aggressive, express low cell-cell adhesion cluster containing claudins (CLDN3/CLDN4/CLDN7) with enrichment of epithelial-to-mesenchymal transition (EMT), immunomodulatory, and transforming growth factor-β (TGF-β) genes. We examined the biological, molecular and prognostic impact of TGF-β upregulation and/or inhibition using in vivo and in vitro methods. Using publically available breast cancer gene expression databases, we show that upregulation and enrichment of a TGF-β gene signature is most frequent in MSL/CL breast cancers and is associated with a worse outcome. Using several MSL/CL breast cancer cell lines, we show that TGF-β elicits significant increases in cellular proliferation, migration, invasion, and motility, whereas these effects can be abrogated by a specific inhibitor against TGF-β receptor I and the anti-diabetic agent metformin, alone or in combination. Prior reports from our lab show that TNBC is exquisitely sensitive to metformin treatment. Mechanistically, metformin blocks endogenous activation of Smad2 and Smad3 and dampens TGF-β-mediated activation of Smad2, Smad3, and ID1 both at the transcriptional and translational level. We report the use of ID1 and ID3 as clinical surrogate markers, where high expression of these TGF-β target genes was correlated to poor prognosis in claudin-low patients. Given TGF-β's role in tumorigenesis and immunomodulation, blockade of this pathway using direct kinase inhibitors or more broadly acting inhibitors may dampen or abolish pro-carcinogenic and metastatic signaling in patients with MCL/CL TNBC. Metformin therapy (with or without other agents) may be a heretofore unrecognized approach to reduce the oncogenic activities associated with TGF-β mediated oncogenesis.

Liu L, Liu X, Ren X, et al.
Smad2 and Smad3 have differential sensitivity in relaying TGFβ signaling and inversely regulate early lineage specification.
Sci Rep. 2016; 6:21602 [PubMed] Free Access to Full Article Related Publications
The transforming growth factor beta (TGFβ) related signaling is one of the most important signaling pathways regulating early developmental events. Smad2 and Smad3 are structurally similar and it is mostly considered that they are equally important in mediating TGFβ signals. Here, we show that Smad3 is an insensitive TGFβ transducer as compared with Smad2. Smad3 preferentially localizes within the nucleus and is thus sequestered from membrane signaling. The ability of Smad3 in oligomerization with Smad4 upon agonist stimulation is also impaired given its unique linker region. Smad2 mediated TGFβ signaling plays a crucial role in epiblast development and patterning of three germ layers. However, signaling unrelated nuclear localized Smad3 is dispensable for TGFβ signaling-mediated epiblast specification, but important for early neural development, an event blocked by TGFβ/Smad2 signaling. Both Smad2 and Smad3 bind to the conserved Smads binding element (SBE), but they show nonoverlapped target gene binding specificity and differential transcriptional activity. We conclude that Smad2 and Smad3 possess differential sensitivities in relaying TGFβ signaling and have distinct roles in regulating early developmental events.

Zhang Q, Chen X, Zhang X, et al.
Knockdown of TMEM14A expression by RNAi inhibits the proliferation and invasion of human ovarian cancer cells.
Biosci Rep. 2016; 36(1):e00298 [PubMed] Free Access to Full Article Related Publications
Transmembrane protein 14A (TMEM14A) is a member of TMEMs. Alterations in TMEMs expression have been identified in several types of cancer, but the expression and function of TMEM14A in ovarian cancer is still unclear. Here, analysis on the expression data of the Cancer Genome Atlas (TCGA) ovarian serous cystadenocarcinoma (OV) dataset demonstrated the overexpression of TMEM14A in ovarian cancer tissues compared with normal tissues, which was consistent with our real-time PCR analysis on ovarian cancer and normal tissues collected from 30 patients. In addition, TMEM14A knockdown in two ovarian cancer cell lines, A2780 and HO-8910, reduced cell proliferation, causes cell cycle arrest and suppressed cell invasion. Moreover, silencing of TMEM14A notably repressed G1/S cell cycle transition and cell invasion via down-regulating the expression of cell cycle related proteins (Cyclin D1, Cyclin E and PCNA) and metastasis-related proteins (MMP-2 and MMP-9), respectively. TMEM14A knockdown significantly reduced the phosphorylation status of Smad2 and Smad3, downstream effectors of TGF-β signalling. In summary, these results indicate that TMEM14A has a pro-tumorigenic effect in ovarian cancer cells, suggesting an important role of this protein in ovarian cancer oncogenesis and metastasis.

Zhang S, Sun WY, Wu JJ, et al.
Decreased expression of the type III TGF-β receptor enhances metastasis and invasion in hepatocellullar carcinoma progression.
Oncol Rep. 2016; 35(4):2373-81 [PubMed] Related Publications
The transforming growth factor β (TGF-β) superfamily of cytokines is multifunctional and involved in the regulation of cell growth and differentiation. TGF-β can induce an epithelial-mesenchymal transition (EMT) of both epithelial and endothelial cells. This has consequences for cancer progression in regards to both migration and invasion abilities. The type III TGF-β receptor (TβRIII) is a ubiquitously expressed TGF-β co-receptor which regulates TGF-β signaling and the progression of various types of cancer. Previous studies have shown that TβRIII exhibits abnormal expression and plays an essential role in regulating cancer invasion and metastasis, while little is known in regards to its role in hepatocellular carcinoma (HCC) progression. In the present study, we designed the present research to study the role of TβRIII in the invasion and metastasis of HCC and the possible mechanisms involved. The results demonstrated decreased expression of TβRIII in HCC patient tissues and human HCC cell lines. TGF-β1 stimulation led to the increased migratory ability and reduced expression of TβRIII in HCC cells. In addition, knockdown of TβRIII by small interfering RNA (siRNA) promoted the migration and invasion of HCC cells and induced activation of the Smad2 and Akt pathways. All the results suggest that TβRIII is a novel suppressor of HCC progression.

Wang X, Chen E, Tang M, et al.
The SMAD2/3 pathway is involved in hepaCAM-induced apoptosis by inhibiting the nuclear translocation of SMAD2/3 in bladder cancer cells.
Tumour Biol. 2016; 37(8):10731-43 [PubMed] Related Publications
The aim of this study was to explore the correlation between hepatocyte cell adhesion molecule (hepaCAM) and SMAD family member 2/3 (SMAD2/3) in bladder carcinoma, and the involvement of the SMAD2/3 pathway in hepaCAM-induced tumor apoptosis. Immunohistochemistry was used to measure hepaCAM and p-SMAD2/3 protein levels in bladder cancer tissues. Flow cytometry and Hoechst staining were used to study the effect of hepaCAM on cellular apoptosis. Western blot was employed to determine the expression of hepaCAM and SMAD2/3/caspase pathway molecules using a hepaCAM overexpression adenovirus, a caspase inhibitor (Z-VAD-FMK), and a SMAD2/3 activator (transforming growth factor (TGF)-β1), respectively. Translocation of p-SMAD2/3 was measured by immunofluorescence and western blot. HepaCAM proteins were significantly decreased (P < 0.05), while p-SMAD2/3 proteins were remarkably increased (P < 0.05) in bladder carcinoma compared to adjacent tissues. However, the low hepaCAM and high p-SMAD2/3 were not statistically associated with clinicopathological characteristics of the patients. A negative linear correlation between hepaCAM and p-SMAD2/3 was observed according to Pearson analysis (r = -0.712/-0.724, P = 0.008/0.011). Overexpression of hepaCAM activated caspase 3/8/9 and downregulated poly-ADP ribose polymerase (PARP) and p-SMAD2/3. Treatment of bladder cancer cells with Z-VAD-FMK + hepaCAM significantly downregulated procaspase 3/8/9 and PARP and induced cellular apoptosis, compared with that using Z-VAD-FMK alone. Similarly, combined treatment of TGF-β1 + hepaCAM significantly downregulated p-SMAD2/3, procaspase 3/8/9, and PARP and induced apoptosis of bladder cancer cells, compared with TGF-β1 alone. Overexpression of hepaCAM prevented the p-SMAD2/3 translocation from the cytoplasm to the nucleus in bladder cancer cells BIU-87 and T24. Our findings uncover that the p-SMAD2/3 pathway is critical for hepaCAM-induced cancer cell apoptosis and provide valuable insights for current and future Ad-hepaCAM and p-SMAD2/3 clinical trials.

Chen CM, Sun LL, Fang RM, Lin LZ
YiQi ChuTan Recipe Inhibits Epithelial Mesenchymal Transition of A549 Cells under Hypoxia.
Cell Mol Biol (Noisy-le-grand). 2016; 62(1):10-5 [PubMed] Related Publications
This study aims to investigate mechanism of YiQi ChuTan Recipe (YCR) for inhibiting epithelial mesenchymal transition (EMT) of A549 cells under hypoxia. Flow cytometry was used to optimize YCR dosage by measuring A549 apoptosis, which were subjected to different treatments, including normal condition, hypoxia, hypoxia+YCR. Cell morphology and expression of EMT were measured with differential interference contrast microscopy, real-time PCR and western blot. Optimized condition of 4 mg/ml YCR and 2% O2 for 72 h was used to establish hypoxia. Under hypoxic condition, morphology of A549 cells changed from oblate fusi-form to elongated spindle. E-cadherin expression decreased while vimentin and fibronectin increased. EMT-related genes expression were significantly increased in hypoxia group compared to control group (P<0.05). After treatment with YCR, mesenchymal cells obviously decreased and EMT-related genes expression was significantly decreased (P<0.05). Changes of E-cadherin, vimentin and fibronection were significantly attenuated by YCR when compared to hypoxia group. Expression of proteins GRP78, SRC, MAPK, smad2/3 were significantly increased in hypoxia group compared to control group, but was significantly inhibited by YCR treatment. In conclusion, A549 cells underwent EMT under hypoxia while YCR reversed the EMT through GRP78, smad2/3 and SRC/MAPK signal pathway.

Zu L, Xue Y, Wang J, et al.
The feedback loop between miR-124 and TGF-β pathway plays a significant role in non-small cell lung cancer metastasis.
Carcinogenesis. 2016; 37(3):333-43 [PubMed] Related Publications
Increasing evidence shows that micro RNAs (miRNAs) play a critical role in tumor development. However, the role of miRNAs in non-small cell lung cancer (NSCLC) metastasis remains largely unknown. Here, we found that miR-124 expression was significantly impaired in NSCLC tissues and associated with its metastasis. In vitro and in vivo experiments indicate that restoring miR-124 expression in NSCLC cells had a marked effect on reducing cell migration, invasion and metastasis. Mechanistic analyses show that Smad4, a cobinding protein in transforming growth factor-β (TGF-β) pathway, was identified as a new target gene of miR-124. Restoring Smad4 expression in miR-124-infected cells could partially rescue miR-124-induced abolition of cell migration and invasion. Notably, upon TGF-β stimulation, phosphorylation of Smad2/3 was modulated by alteration of miR-124 or Smad4 expression, followed by inducing some special transcription of downstream genes including Snail, Slug and ZEB2, all of which may trigger epithelial-mesenchymal transition and be associated with NSCLC metastasis. Moreover, activation of TGF-β pathway may enhance expression of DNMT3a, leading to hypermethylation on miR-124 promoter. Therefore, heavily loss of miR-124 expression further enhances Smad4 level by this feedback loop. Taken together, our data show for the first time that the feedback loop between miR-124 and TGF-β pathway may play a significant role in NSCLC metastasis. Targeting the loop may prove beneficial to prevent metastasis and provide a more effective therapeutic strategy for NSCLC.

Choi YJ, Baek GY, Park HR, et al.
Smad2/3-Regulated Expression of DLX2 Is Associated with Radiation-Induced Epithelial-Mesenchymal Transition and Radioresistance of A549 and MDA-MB-231 Human Cancer Cell Lines.
PLoS One. 2016; 11(1):e0147343 [PubMed] Free Access to Full Article Related Publications
The control of radioresistance and metastatic potential of surviving cancer cells is important for improving cancer eradication by radiotheraphy. The distal-less homeobox2 (DLX2) gene encodes for a homeobox transcription factor involved in morphogenesis and its deregulation was found in human solid tumors and hematologic malignancies. Here we investigated the role of DLX2 in association with radiation-induced epithelial to mesenchymal transition (EMT) and stem cell-like properties and its regulation by Smad2/3 signaling in irradiated A549 and MDA-MB-231 human cancer cell lines. In irradiated A549 and MDA-MB-231 cells, EMT was induced as demonstrated by EMT marker expression, phosphorylation of Smad2/3, and migratory and invasive ability. Also, irradiated A549 and MDA-MB-231 cells showed increased cancer stem cells (CSCs) marker. Interestingly, DLX2 was overexpressed upon irradiation. Therefore, we examined the role of DLX2 in radiation-induced EMT and radioresistance. The overexpression of DLX2 alone induced EMT, migration and invasion, and CSC marker expression. The reduced colony-forming ability in irradiated cells was partially restored by DLX2 overexpression. On the other hand, the depletion of DLX2 using si-RNA abolished radiation-induced EMT, CSC marker expression, and phosphorylation of Smad2/3 in irradiated A549 and MDA-MB-231 cells. Also, depletion of DLX2 increased the radiation sensitivity in both cell lines. Moreover, knockdown of Smad2/3, a key activator of TGF-β1 pathway, abrogated the radiation-induced DLX2 expression, indicating that radiation-induced DLX2 expression is dependent on Smad2/3 signaling. These results demonstrated that DLX2 plays a crucial role in radioresistance, radiation-induced EMT and CSC marker expression, and the expression of DLX2 is regulated by Smad2/3 signaling in A549 and MDA-MB-231 cell lines.

Petrillo M, Zannoni GF, Beltrame L, et al.
Identification of high-grade serous ovarian cancer miRNA species associated with survival and drug response in patients receiving neoadjuvant chemotherapy: a retrospective longitudinal analysis using matched tumor biopsies.
Ann Oncol. 2016; 27(4):625-34 [PubMed] Related Publications
BACKGROUND: Neoadjuvant chemotherapy (NACT) has been recognized as a reliable therapeutic strategy in patients with unresectable advanced epithelial ovarian cancer (EOC). The molecular events leading to platinum (Pt) response in NACT settings have hitherto not been explored. In the present work, longitudinal changes of miRNA expression profile were investigated to identify miRNA families with prognostic role in high-grade serous EOC patients who received the NACT regimen.
PATIENTS AND METHODS: One hundred sixty-four matched tumor biopsies taken at initial laparoscopic evaluation and at interval-debulking surgery (IDS) after four courses of Pt-based therapy were selected from 82 stage IIIC-IV high-grade serous-EOC patients that were judged unsuitable for complete primary debulking and subjected the NACT protocol. miRNA profiling by microarray, real-time PCR and immuno-histochemical staining for Smad2 phosphorylation (P-Smad2) were used for data analysis.
RESULTS: Analysis revealed that 369 miRNAs were differentially expressed in matched biopsies (referred to as DEMs). DEMs were not scattered across the genome, but clustered into families: miR-199, let-7, miR-30, miR-181 and miR-29. Multivariate analysis showed that miR-199a-3p, miR-199a-5p, miR-181a-5p and let-7g-5p associated with overall and progression-free survival (P < 0.05); miR-199a-3p, miR-199a-5p and miR-181a-5p associated with residual tumor volume and Pt-free interval (P < 0.05). Immuno-histochemical staining confirmed an enrichment of P-Smad2, a marker of transforming growth factor-β activation, in tumors from patients with shorter PFS and OS, and with high levels of expression of miR-181a-5p (P < 0.05). Kaplan-Meier curves plotting concomitant expression of P-Smad2 and miR-181a-5p show significant differences in PFS and OS compared with those depicting the expression of each biomarker alone (P < 0.001).
CONCLUSIONS: This study describes several miRNA families with a prognostic role in the NACT setting. It also confirms that concomitant analysis of P-Smad2 and miR-181a-5p in surgical samples may be capable of identifying those ovarian cancer patients with poor outcome and little chance of response to Pt-based NACT.

Pathria G, Garg B, Wagner C, et al.
RanBP3 Regulates Melanoma Cell Proliferation via Selective Control of Nuclear Export.
J Invest Dermatol. 2016; 136(1):264-74 [PubMed] Related Publications
Chromosome region maintenance 1-mediated nucleocytoplasmic transport has been shown as a potential anticancer target in various malignancies. However, the role of the most characterized chromosome region maintenance 1 cofactor ran binding protein 3 (RanBP3) in cancer cell biology has never been investigated. Utilizing a loss-of-function experimental setting in a vast collection of genetically varied melanoma cell lines, we observed the requirement of RanBP3 in melanoma cell proliferation and survival. Mechanistically, we suggest the reinstatement of transforming growth factor-β (TGF-β)-Smad2/3-p21(Cip1) tumor-suppressor axis as part of the RanBP3 silencing-associated antiproliferative program. Employing extensive nuclear export sequence analyses and immunofluorescence-based protein localization studies, we further present evidence suggesting the requirement of RanBP3 function for the nuclear exit of the weak nuclear export sequence-harboring extracellular signal-regulated kinase protein, although it is dispensable for general CRM1-mediated nuclear export of strong nuclear export sequence-harboring cargoes. Rendering mechanistic support to RanBP3 silencing-mediated apoptosis, consequent to extracellular signal-regulated kinase nuclear entrapment, we observed increased levels of cytoplasmically restricted nonphosphorylated/active proapoptotic Bcl-2-antagonist of cell death (BAD) protein. Last, we present evidence suggesting the frequently activated mitogen-activated protein kinase signaling in melanoma as a potential founding basis for a deregulated post-translational control of RanBP3 activity. Collectively, the presented data suggest RanBP3 as a potential target for therapeutic intervention in human melanoma.

Codó P, Weller M, Kaulich K, et al.
Control of glioma cell migration and invasiveness by GDF-15.
Oncotarget. 2016; 7(7):7732-46 [PubMed] Free Access to Full Article Related Publications
Growth and differentiation factor (GDF)-15 is a member of the transforming growth factor (TGF)-β family of proteins. GDF-15 levels are increased in the blood and cerebrospinal fluid of glioblastoma patients. Using a TCGA database interrogation, we demonstrate that high GDF-15 expression levels are associated with poor survival of glioblastoma patients. To elucidate the role of GDF-15 in glioblastoma in detail, we confirmed that glioma cells express GDF-15 mRNA and protein in vitro. To allow for a detailed functional characterization, GDF-15 expression was silenced using RNA interference in LNT-229 and LN-308 glioma cells. Depletion of GDF-15 had no effect on cell viability. In contrast, GDF-15-deficient cells displayed reduced migration and invasion, in the absence of changes in Smad2 or Smad1/5/8 phosphorylation. Conversely, exogenous GDF-15 stimulated migration and invasiveness. Large-scale expression profiling revealed that GDF-15 gene silencing resulted in minor changes in the miRNA profile whereas several genes, including members of the plasminogen activator/inhibitor complex, were deregulated at the mRNA level. One of the newly identified genes induced by GDF-15 gene silencing was the serpin peptidase inhibitor, clade E nexin group 1 (serpine1) which is induced by TGF-β and known to inhibit migration and invasiveness. However, serpine1 down-regulation alone did not mediate GDF-15-induced promotion of migration and invasiveness. Our findings highlight the complex contributions of GDF-15 to the invasive phenotype of glioma cells and suggest anti-GDF-15 approaches as a promising therapeutic strategy.

Liu L, Zhao Z, Zhou W, et al.
Enhanced Expression of miR-425 Promotes Esophageal Squamous Cell Carcinoma Tumorigenesis by Targeting SMAD2.
J Genet Genomics. 2015; 42(11):601-11 [PubMed] Related Publications
Esophageal squamous cell carcinoma (ESCC) is one of the most common and deadly cancers in the world. Currently, clinical therapy of ESCC remains limited and the five-year survival rate is poor. The function of miR-425 has been reported in multiple human cancers. However, the tumorigenic role and clinical significance of miR-425 in ESCC remains unclear. We found that enhanced expression of miR-425 in ESCC cell lines not only promoted cell proliferation and colony formation, but also increased cellular metastasis. Furthermore, we revealed the mechanism that miR-425 inhibited the expression of SMAD2 by targeting the second binding site in the 3'-untranslated region (3'-UTR) in ESCC. This mode of action influenced not only SMAD2 mRNA expression but also protein expression. In addition, we detected the expression of miR-425 in ESCC tissues and plasma. Moreover, we analyzed the relationship between miR-425 expression and SMAD2 mRNA expression. We found that miR-425 was overexpressed in ESCC tissues and the plasma relative to adjacent normal tissues and plasma of healthy individuals. Furthermore, there was a negative correlation between miR-425 expression and SMAD2. Taken together, our results show that miR-425 functions as an oncogene by targeting the 3'-UTR of SMAD2 and indicate the potential utility of plasma miR-425 as a novel biomarker for ESCC diagnosis.

Akbari A, Mobini GR, Maghsoudi R, et al.
Modulation of transforming growth factor‑β signaling transducers in colon adenocarcinoma cells induced by staphylococcal enterotoxin B.
Mol Med Rep. 2016; 13(1):909-14 [PubMed] Related Publications
Colorectal cancer (CRC) is a notable cause of cancer‑associated mortality worldwide, making it a pertinent topic for the study of cancer and its treatment. Staphylococcal enterotoxin B (SEB), an enterotoxin produced by Staphylococcus aureus, has been demonstrated to exert anticancer and antimetastatic effects due to its ability to modify cell immunity and cellular signaling pathways. In the current study, SEB was investigated, including whether it exerts its growth inhibitory effects on colon adenocarcinoma cells. This may occur through the manipulation of a key tumor growth factor, termed transforming growth factor‑β (TGF‑β), and its signaling pathway transducer, Smad2/3. The human colon adenocarcinoma HCT116 cell line was treated with different concentrations of SEB, and cell number was measured using MTT assay at different treatment times. Smad2/3 RNA expression level was analyzed in untreated or SEB‑treated cells using quantitative polymerase chain reaction, which indicated significant differences between cell viability and Smad2/3 expression levels. SEB effectively downregulated Smad2/3 expression in the HCT116 cells at concentrations of 1 and 2 µg/ml (P=0.0021 and P=0.0017, respectively). SEB concentrations that were effective at inhibiting Smad2/3 expression were correlated with those able to inhibit the proliferation of the cancer cells. SEB inhibited Smad2/3 expression at the mRNA level in a concentration‑ and time‑dependent manner. The present study thus proposed SEB as an agent able to significantly reduce Smad2/3 expression in colon cancer cells, provoking moderate TGF‑β growth signaling and the reduction of tumor cell proliferation.

Wang W, Song XW, Bu XM, et al.
PDCD2 and NCoR1 as putative tumor suppressors in gastric gastrointestinal stromal tumors.
Cell Oncol (Dordr). 2016; 39(2):129-37 [PubMed] Related Publications
PURPOSE: Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors in the gastrointestinal tract. Previously, PDCD2 (programmed cell death protein 2) has been identified as a putative tumor suppressor in gastric cancer. As yet, however, no reports on PDCD2 expression and its physical interactor NCoR1 (nuclear receptor co-repressor), and their effects in GIST have been reported.
METHODS: The expression of PDCD2 and NCoR1 was assessed in 43 primary gastric GIST and normal gastric tissue samples using Western blotting and quantitative real-time PCR. Next, associations between PDCD2 and NCoR1 expression and various clinicopathological features, including survival, were determined. To assess the effects of PDCD2 and NCoR1 expression in vitro, two GIST-derived cell lines (GIST-T1 and GIST882) were (co-)transfected with the expression vectors pEGFP-N1-PDCD2 and pcDNA3.1-NCoR1, after which the cells were subjected to CCK-8, PI staining and Annexin V-FITC/PI double staining assays, respectively. Finally, the mechanisms of action of PDCD2 and NCoR1 in GIST-derived cells were determined using immunoprecipitation and Western blotting assays.
RESULTS: We found that the PDCD2 and NCoR1 protein levels were lower in gastric GIST tissues than in normal gastric tissues. The PDCD2 and NCoR1 expression levels were found to be significantly associated with the survival of the patients. Through exogenous expression analyses, we found that PDCD2 and NCoR1 can decrease proliferation, and increase apoptosis and G1 cell cycle arrest, in GIST-derived cells. Furthermore, we found that PDCD2 and NCoR1 can activate Smad2 and Smad3.
CONCLUSIONS: Our data indicate that both PDCD2 and NCoR1 may act as tumor suppressors in GIST cells through the Smad signaling pathway.

Bartscht T, Rosien B, Rades D, et al.
Dasatinib blocks transcriptional and promigratory responses to transforming growth factor-beta in pancreatic adenocarcinoma cells through inhibition of Smad signalling: implications for in vivo mode of action.
Mol Cancer. 2015; 14:199 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: We have previously shown in pancreatic ductal adenocarcinoma (PDAC) cells that the SRC inhibitors PP2 and PP1 effectively inhibited TGF-β1-mediated cellular responses by blocking the kinase function of the TGF-β type I receptor ALK5 rather than SRC. Here, we investigated the ability of the clinically utilised SRC/ABL inhibitor dasatinib to mimic the PP2/PP1 effect.
METHODS: The effect of dasatinib on TGF-β1-dependent Smad2/3 phosphorylation, general transcriptional activity, gene expression, cell motility, and the generation of tumour stem cells was measured in Panc-1 and Colo-357 cells using immunoblotting, reporter gene assays, RT-PCR, impedance-based real-time measurement of cell migration, and colony formation assays, respectively.
RESULTS: In both PDAC cell lines, dasatinib effectively blocked TGF-β1-induced Smad phosphorylation, activity of 3TPlux and pCAGA(12)-luc reporter genes, cell migration, and expression of individual TGF-β1 target genes associated with epithelial-mesenchymal transition and invasion. Moreover, dasatinib strongly interfered with the TGF-β1-induced generation of tumour stem cells as demonstrated by gene expression analysis and single cell colony formation. Dasatinib also inhibited the high constitutive migratory activity conferred on Panc-1 cells by ectopic expression of kinase-active ALK5.
CONCLUSIONS: Our data suggest that the clinical efficiency of dasatinib may in part be due to cross-inhibition of tumour-promoting TGF-β signalling. Dasatinib may be useful as a dual TGF-β/SRC inhibitor in experimental and clinical therapeutics to prevent metastatic spread in late-stage PDAC and other tumours.

Qu MH, Han C, Srivastava AK, et al.
miR-93 promotes TGF-β-induced epithelial-to-mesenchymal transition through downregulation of NEDD4L in lung cancer cells.
Tumour Biol. 2016; 37(4):5645-51 [PubMed] Related Publications
The level of microRNA-93 (miR-93) in tumors has been recently reported to be negatively correlated with survival of lung cancer patients. Considering that the most devastating aspect of lung cancer is metastasis, which can be promoted by transforming growth factor-β (TGF-β)-induced epithelial-to-mesenchymal transition (EMT), we sought to determine whether miR-93 is involved in this process. Here, we report that a previously unidentified target of miR-93, neural precursor cell expressed developmentally downregulated gene 4-like (NEDD4L), is able to mediate TGF-β-mediated EMT in lung cancer cells. miR-93 binds directly to the 3'-UTR of the NEDD4L messenger RNA (mRNA), leading to a downregulation of NEDD4L expression at the protein level. We next demonstrated that the downregulation of NEDD4L enhanced, while overexpression of NEDD4L reduced TGF-β signaling, reflected by increased phosphorylation of SMAD2 in the lung cancer cell line after TGF-β treatment. Furthermore, overexpression of miR-93 in lung cancer cells promoted TGF-β-induced EMT through downregulation of NEDD4L. The analysis of publicly available gene expression array datasets indicates that low NEDD4L expression correlates with poor outcomes among patients with lung cancer, further supporting the oncogenic role of miR-93 in lung tumorigenesis and metastasis.

Choi HS, Jain V, Krueger B, et al.
Kaposi's Sarcoma-Associated Herpesvirus (KSHV) Induces the Oncogenic miR-17-92 Cluster and Down-Regulates TGF-β Signaling.
PLoS Pathog. 2015; 11(11):e1005255 [PubMed] Free Access to Full Article Related Publications
KSHV is a DNA tumor virus that causes Kaposi's sarcoma. Upon KSHV infection, only a limited number of latent genes are expressed. We know that KSHV infection regulates host gene expression, and hypothesized that latent genes also modulate the expression of host miRNAs. Aberrant miRNA expression contributes to the development of many types of cancer. Array-based miRNA profiling revealed that all six miRNAs of the oncogenic miR-17-92 cluster are up-regulated in KSHV infected endothelial cells. Among candidate KSHV latent genes, we found that vFLIP and vCyclin were shown to activate the miR-17-92 promoter, using luciferase assay and western blot analysis. The miR-17-92 cluster was previously shown to target TGF-β signaling. We demonstrate that vFLIP and vCyclin induce the expression of the miR-17-92 cluster to strongly inhibit the TGF-β signaling pathway by down-regulating SMAD2. Moreover, TGF-β activity and SMAD2 expression were fully restored when antagomirs (inhibitors) of miR-17-92 cluster were transfected into cells expressing either vFLIP or vCyclin. In addition, we utilized viral genetics to produce vFLIP or vCyclin knock-out viruses, and studied the effects in infected TIVE cells. Infection with wildtype KSHV abolished expression of SMAD2 protein in these endothelial cells. While single-knockout mutants still showed a marked reduction in SMAD2 expression, TIVE cells infected by a double-knockout mutant virus were fully restored for SMAD2 expression, compared to non-infected TIVE cells. Expression of either vFLIP or vCycIin was sufficient to downregulate SMAD2. In summary, our data demonstrate that vFLIP and vCyclin induce the oncogenic miR-17-92 cluster in endothelial cells and thereby interfere with the TGF-β signaling pathway. Manipulation of the TGF-β pathway via host miRNAs represents a novel mechanism that may be important for KSHV tumorigenesis and angiogenesis, a hallmark of KS.

Cantelli G, Orgaz JL, Rodriguez-Hernandez I, et al.
TGF-β-Induced Transcription Sustains Amoeboid Melanoma Migration and Dissemination.
Curr Biol. 2015; 25(22):2899-914 [PubMed] Free Access to Full Article Related Publications
Cell migration underlies metastatic dissemination of cancer cells, and fast "amoeboid" migration in the invasive fronts of tumors is controlled by high levels of actomyosin contractility. How amoeboid migration is regulated by extracellular signals and sustained over time by transcriptional changes is not fully understood. Transforming growth factor β (TGF-β) is well known to promote epithelial-to-mesenchymal transition (EMT) and contribute to metastasis, but melanocytes are neural crest derivatives that have undergone EMT during embryonic development. Surprisingly, we find that in melanoma, TGF-β promotes amoeboid features such as cell rounding, membrane blebbing, high levels of contractility, and increased invasion. Using genome-wide transcriptomics, we find that amoeboid melanoma cells are enriched in a TGF-β-driven signature. We observe that downstream of TGF-β, SMAD2 and its adaptor CITED1 control amoeboid behavior by regulating the expression of key genes that activate contractile forces. Moreover, CITED1 is highly upregulated during melanoma progression, and its high expression is associated with poor prognosis. CITED1 is coupled to a contractile-rounded, amoeboid phenotype in a panel of 16 melanoma cell lines, in mouse melanoma xenografts, and in 47 human melanoma patients. Its expression is also enriched in the invasive fronts of lesions. Functionally, we show how the TGF-β-SMAD2-CITED1 axis promotes different steps associated with progression: melanoma detachment from keratinocytes, 2D and 3D migration, attachment to endothelial cells, and in vivo lung metastatic initial colonization and outgrowth. We propose a novel mechanism by which TGF-β-induced transcription sustains actomyosin force in melanoma cells and thereby promotes melanoma progression independently of EMT.

Ko H, Jeon H, Lee D, et al.
Sanguiin H6 suppresses TGF-β induction of the epithelial-mesenchymal transition and inhibits migration and invasion in A549 lung cancer.
Bioorg Med Chem Lett. 2015; 25(23):5508-13 [PubMed] Related Publications
In the epithelial-mesenchymal transition (EMT), an important cellular process, epithelial cells become mesenchymal cells. This process is also critically involved in cancer metastasis. Sanguiin H6 is a compound derived from ellagitannin, which is found in berries. Sanguiin H6 shows various pharmacological properties, including anti-angiogenic activity. Because the possible role of sanguiin H6 in the EMT and the underlying molecular mechanisms are unclear, we investigated the effect of sanguiin H6 on the EMT. Transforming growth factor-beta 1 (TGF-β1) induces the EMT and promotes lung adenocarcinoma migration and invasion through the Smad2/3 signaling pathway. Thus, to understand the inhibitory effects of sanguiin H6 on lung cancer migration and invasion, we investigated the ability of sanguiin H6 to inhibit TGF-β1-induced EMT in the A549 cell line. We found that sanguiin H6 significantly prevented the activation of Smad2/3 signaling pathway by TGF-β1. Additionally, sanguiin H6 increased the expression of the epithelial marker E-cadherin and repressed the expression of Snail and the mesenchymal marker N-cadherin during TGF-β1-induced EMT. Moreover, sanguiin H6 regulated the expression of EMT-dependent genes induced by TGF-β1. Finally, sanguiin H6 inhibited the migration and invasion of TGF-β1-stimulated A549 cells. Taken together, our findings provide new evidence that sanguiin H6 suppresses lung cancer migration and invasion in vitro by inhibiting TGF-β1 induction of the EMT.

Li C, Wang J, Kong J, et al.
GDF15 promotes EMT and metastasis in colorectal cancer.
Oncotarget. 2016; 7(1):860-72 [PubMed] Free Access to Full Article Related Publications
Metastasis is the major cause of cancer deaths, and the epithelial-mesenchymal transition (EMT) has been considered to be a fundamental event in cancer metastasis. However, the role of growth differentiation factor 15 (GDF15) in colorectal cancer (CRC) metastasis and EMT remains poorly understood. Here, we showed that GDF15 promoted CRC cell metastasis both in vitro and in vivo. In addition, the EMT process was enhanced by GDF15 through binding to TGF-β receptor to activate Smad2 and Smad3 pathways. Clinical data showed GDF15 level in tumor tissues, and the serum was significantly increased, in which high GDF15 level correlated with a reduced overall survival in CRC. Thus, GDF15 may promote colorectal cancer metastasis through activating EMT. Promisingly, GDF15 could be considered as a novel prognostic marker for CRC in the clinic.

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