Gene Summary

Gene:SMAD7; SMAD family member 7
Aliases: CRCS3, MADH7, MADH8
Summary:The protein encoded by this gene is a nuclear protein that binds the E3 ubiquitin ligase SMURF2. Upon binding, this complex translocates to the cytoplasm, where it interacts with TGF-beta receptor type-1 (TGFBR1), leading to the degradation of both the encoded protein and TGFBR1. Expression of this gene is induced by TGFBR1. Variations in this gene are a cause of susceptibility to colorectal cancer type 3 (CRCS3). Several transcript variants encoding different isoforms have been found for this gene. [provided by RefSeq, Jun 2010]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:mothers against decapentaplegic homolog 7
Source:NCBIAccessed: 30 August, 2019


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 (1994-2019)
Graph generated 30 August 2019 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 30 August, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (5)

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: SMAD7 (cancer-related)

Shen DW, Li YL, Hou YJ, et al.
MicroRNA-543 promotes cell invasion and impedes apoptosis in pituitary adenoma via activating the Wnt/β-catenin pathway by negative regulation of Smad7.
Biosci Biotechnol Biochem. 2019; 83(6):1035-1044 [PubMed] Related Publications
Pituitary adenomas (PA) are commonly occurring benign neoplasms. Identification of molecular pathway resulting in pituitary tumorigenesis remains challenges in endocrine oncology. The present study was conducted with aim of investigating the role of microRNA-543 (miR-543) in PA development. Up-regulated miR-543 and downregulated Smad7 were observed in PA tissues. Afterwards, the specific mechanism of miR-543 and Smad7 in PA were determined with the use of ectopic expression, depletion and reporter assay experiments. Smad7 was confirmed as a target gene of miR-543. HP75 cells treated with overexpressed miR-543 exhibited increased cell proliferation, migration and invasion, while decreased cell apoptosis as well as expression of Cleaved caspase-3 and Cleaved caspase-8 were observed. Suppression of miR-543 contributed to an opposite trend to the above findings. Based on the findings, the inhibition of miR-543 was found to play a tumor suppressive role in PA through the down-regulation of Wnt/β-catenin pathway by negatively regulating Smad7.

Manzanarez-Ozuna E, Flores DL, Gutiérrez-López E, et al.
Model based on GA and DNN for prediction of mRNA-Smad7 expression regulated by miRNAs in breast cancer.
Theor Biol Med Model. 2018; 15(1):24 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The Smad7 protein is negative regulator of the TGF-β signaling pathway, which is upregulated in patients with breast cancer. miRNAs regulate proteins expressions by arresting or degrading the mRNAs. The purpose of this work is to identify a miRNAs profile that regulates the expression of the mRNA coding for Smad7 in breast cancer using the data from patients with breast cancer obtained from the Cancer Genome Atlas Project.
METHODS: We develop an automatic search method based on genetic algorithms to find a predictive model based on deep neural networks (DNN) which fit the set of biological data and apply the Olden algorithm to identify the relative importance of each miRNAs.
RESULTS: A computational model of non-linear regression is shown, based on deep neural networks that predict the regulation given by the miRNA target transcripts mRNA coding for Smad7 protein in patients with breast cancer, with R
CONCLUSIONS: We developed a genetic algorithm to select best features as DNN inputs (miRNAs). The genetic algorithm also builds the best DNN architecture by optimizing the parameters. Although the confirmation of the results by laboratory experiments has not occurred, the results allow suggesting that miRNAs profile could be used as biomarkers or targets in targeted therapies.

Ryu TY, Kim K, Kim SK, et al.
SETDB1 regulates SMAD7 expression for breast cancer metastasis.
BMB Rep. 2019; 52(2):139-144 [PubMed] Free Access to Full Article Related Publications
Breast cancer (BRC) is the most invasive cancer in women. Although the survival rate of BRC is gradually increasing due to improved screening systems, development of novel therapeutic targets for inhibition of BRC proliferation, metastasis and recurrence have been constantly needed. Thus, in this study, we identified overexpression of SETDB1 (SET Domain Bifurcated 1), a histone methyltransferase, in RNA-seq data of BRC derived from TCGA portal. In Gene Ontology (GO) analysis, cell migration-related GO terms were enriched, and we confirmed down-regulation of cell migration/invasion and alteration of EMT /MET markers after knockdown of SETDB1. Moreover, gene network analysis showed that SMAD7 expression is regulated by SETDB1 levels, indicating that up-regulation of SMAD7 by SETDB1 knockdown inhibited BRC metastasis. Therefore, development of SETDB1 inhibitors and functional studies may help develop more effective clinical guidelines for BRC treatment. [BMB Reports 2019; 52(2): 139-144].

Abd El-Fattah AA, Sadik NAH, Shaker OG, Mohamed Kamal A
Single Nucleotide Polymorphism in SMAD7 and CHI3L1 and Colorectal Cancer Risk.
Mediators Inflamm. 2018; 2018:9853192 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer (CRC) is one of the leading cancers throughout the world. It represents the third most common cancer and the fourth in mortality. Most of CRC are sporadic, arise with no known high-penetrant genetic variation and with no previous family history. The etiology of sporadic CRC is considered to be multifactorial and arises from the interaction of genetic variants of low-penetrant genes and environmental risk factors. The most common well-studied genetic variation is single nucleotide polymorphisms (SNPs). SNP arises as a point mutation. If the frequency of the sequence variation reaches 1% or more in the population, it is referred to as polymorphism, but if it is lower than 1%, the allele is typically considered as a mutation. Lots of SNPs have been associated with CRC development and progression, for example, genes of TGF-

Zhai W, Li S, Zhang J, et al.
Sunitinib-suppressed miR-452-5p facilitates renal cancer cell invasion and metastasis through modulating SMAD4/SMAD7 signals.
Mol Cancer. 2018; 17(1):157 [PubMed] Free Access to Full Article Related Publications
PURPOSE: Although microRNAs (miRNAs) were revealed as crucial modulators in tumor metastasis and target therapy, our understanding of their roles in metastatic renal cell carcinoma (mRCC) and Sunitinib treatment was limited. Here we sought to identify human miRNAs that acted as key regulators in renal cancer metastasis and Sunitinib treatment.
EXPERIMENTAL DESIGN: We focused on 2 published microarray data to select out our anchored miRNA and then explored the roles of miR-452-5p both in vitro and in vivo, which was downregulated after Sunitinib treatment while upregulated in metastasis renal cell carcinoma (RCC) tissues.
RESULTS: Here, we discovered that treating with Sunitinib, the targeted receptor tyrosine kinase inhibitor (TKI), inhibited renal cancer cell migration and invasion via attenuating the expression of miR-452-5p. The novel identified miR-452-5p was upregulated and associated with poor prognosis in RCC. Preclinical studies using multiple RCC cells and xenografts model illustrated that miR-452-5p could promote RCC cell migration and invasion in vitro and in vivo. Mechanistically, P65 could directly bind to the miR-452-5p promoter and thus transcriptionally induce miR-452-5p expression, which led to post-transcriptionally abrogate SMAD4 expression, thus inhibition of its downstream gene SMAD7.
CONCLUSION: Our study presented a road map for targeting this newly identified miR-452-5p and its SMAD4/SMAD7 signals pathway, which imparted a new potential therapeutic strategy for mRCC treatment.

Kamiza AB, Wang WC, You JF, et al.
Anticancer Res. 2018; 38(10):5983-5990 [PubMed] Related Publications
BACKGROUND/AIM: Epidermal growth factor receptor (EGFR), mothers against decapentaplegic homolog 7 (SMAD7) and transforming growth factor betta (TGFB) are crucial for colorectal cancer (CRC) tumorigenesis. This study investigated whether polymorphisms in EGFR, SMAD7, and TGFB are associated with CRC risk in patients with Lynch syndrome.
MATERIALS AND METHODS: Genotyping was performed using Sequenom iPLEX MassArray. Association between genetic polymorphisms and CRC was assessed using a weighted Cox proportional hazard model.
RESULTS: Patients carrying the AA genotype of EGFR rs2227983 had a significantly higher CRC risk than those carrying the G allele (HR=2.55, 95% CI=1.25-5.17). The dominant model of SMAD7 rs12953717 (CT + TT genotypes) significantly increased CRC risk (HR=2.17, 95% CI=1.12-4.16) when compared to the wild-type CC genotype. Similarly, the GG genotype of TGFBR2 rs6785358 significantly increased the risk of CRC (HR=21.1, 95% CI=5.06-88.1) compared to the AA genotype.
CONCLUSION: EGFR, SMAD7, and TGFBR2 are associated with CRC risk in patients with Lynch syndrome.

Fiedler D, Heselmeyer-Haddad K, Hirsch D, et al.
Single-cell genetic analysis of clonal dynamics in colorectal adenomas indicates CDX2 gain as a predictor of recurrence.
Int J Cancer. 2019; 144(7):1561-1573 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Colorectal adenomas are common precancerous lesions with the potential for malignant transformation to colorectal adenocarcinoma. Endoscopic polypectomy provides an opportunity for cancer prevention; however, recurrence rates are high. We collected formalin-fixed paraffin-embedded tissue of 15 primary adenomas with recurrence, 15 adenomas without recurrence, and 14 matched pair samples (primary adenoma and the corresponding recurrent adenoma). The samples were analysed by array-comparative genomic hybridisation (aCGH) and single-cell multiplex interphase fluorescence in situ hybridisation (miFISH) to understand clonal evolution, to examine the dynamics of copy number alterations (CNAs) and to identify molecular markers for recurrence prediction. The miFISH probe panel consisted of 14 colorectal carcinogenesis-relevant genes (COX2, PIK3CA, APC, CLIC1, EGFR, MYC, CCND1, CDX2, CDH1, TP53, HER2, SMAD7, SMAD4 and ZNF217), and a centromere probe (CEP10). The aCGH analysis confirmed the genetic landscape typical for colorectal tumorigenesis, that is, CNAs of chromosomes 7, 13q, 18 and 20q. Focal aberrations (≤10 Mbp) were mapped to chromosome bands 6p22.1-p21.33 (33.3%), 7q22.1 (31.4%) and 16q21 (29.4%). MiFISH detected gains of EGFR (23.6%), CDX2 (21.8%) and ZNF217 (18.2%). Most adenomas exhibited a major clone population which was accompanied by multiple smaller clone populations. Gains of CDX2 were exclusively seen in primary adenomas with recurrence (25%) compared to primary adenomas without recurrence (0%). Generation of phylogenetic trees for matched pair samples revealed four distinct patterns of clonal dynamics. In conclusion, adenoma development and recurrence are complex genetic processes driven by multiple CNAs whose evaluations by miFISH, with emphasis on CDX2, might serve as a predictor of recurrence.

Oikawa D, Shiota M, Goto E, et al.
Generation of Rat Monoclonal Antibodies Against a Deubiquitinase, Ovarian Tumor Domain-Containing Protein 1.
Monoclon Antib Immunodiagn Immunother. 2018; 37(4):180-184 [PubMed] Related Publications
Ovarian tumor domain-containing protein 1 (OTUD1), an OTU-family deubiquitinating enzyme, has been reported to be involved in cancer progression through the regulation of p53 and SMAD7. However, the precise pathophysiological functions of OTUD1 remain elusive. Here, we report the establishment of OTUD1-specific monoclonal antibodies (mAbs), using the rat medial iliac lymph node method. The generated antibodies recognize the N-terminal portion (aa. 1-290) of human and mouse OTUD1 proteins. In addition, immunofluorescent staining and subcellular fractionation analyses using these antibodies indicated that OTUD1 is predominantly localized in the cytosol. Thus, these mAbs can be further used to elucidate cellular functions of OTUD1 and its involvement in processes such as cancer progression.

Chen E, Li Q, Wang H, et al.
MiR-92a promotes tumorigenesis of colorectal cancer, a transcriptomic and functional based study.
Biomed Pharmacother. 2018; 106:1370-1377 [PubMed] Related Publications
Colorectal cancer (CRC) is a leading cause of cancer deaths worldwide. Accumulation of varieties of epigenetic changes, including miRNA regulation, is one of the fundamental processes driving CRC initiation and progression. Mir-92a has been reported in several studies as an oncogene, and particularly in colorectal cancer, it has become a useful biomarker for early detection of CRC in both serum or stool. The Cancer Genome Atlas (TCGA) is a powerful database to analyze cancer-related genes and their correlation with patients' pathological information. However, miR-92a expression and its regulating target genes has yet to be investigated in TCGA system. In this study, we found miR-92a expression is associated with CRC pathological process. Notably, high expression of miR-92a mainly occurs in microsatellite-stable (MSS) cases. Further experiments showed exogenous introduction of miR-92a into LoVo and SW480 cells could enhance cell proliferation, migration, and invasion, whereas inhibition of miR-92a showed the opposite effects. A system analysis based on binding capacity and expression correlation analysis confirmed DKK3 and KLF4 are the top target genes of miR-92a, and novel target SMAD7 highlights the role of miR-92a in BMPs/SMAD pathway. In conclusion, miR-92a acts as an oncomir and directly targets Wnt/β-catenin, PTEN/Akt/FoxO, and BMP/Smads related genes, thus participates in CRC progression.

Cologne J, Loo L, Shvetsov YB, et al.
Stepwise approach to SNP-set analysis illustrated with the Metabochip and colorectal cancer in Japanese Americans of the Multiethnic Cohort.
BMC Genomics. 2018; 19(1):524 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
BACKGROUND: Common variants have explained less than the amount of heritability expected for complex diseases, which has led to interest in less-common variants and more powerful approaches to the analysis of whole-genome scans. Because of low frequency (low statistical power), less-common variants are best analyzed using SNP-set methods such as gene-set or pathway-based analyses. However, there is as yet no clear consensus regarding how to focus in on potential risk variants following set-based analyses. We used a stepwise, telescoping approach to analyze common- and rare-variant data from the Illumina Metabochip array to assess genomic association with colorectal cancer (CRC) in the Japanese sub-population of the Multiethnic Cohort (676 cases, 7180 controls). We started with pathway analysis of SNPs that are in genes and pathways having known mechanistic roles in colorectal cancer, then focused on genes within the pathways that evidenced association with CRC, and finally assessed individual SNPs within the genes that evidenced association. Pathway SNPs downloaded from the dbSNP database were cross-matched with Metabochip SNPs and analyzed using the logistic kernel machine regression approach (logistic SNP-set kernel-machine association test, or sequence kernel association test; SKAT) and related methods.
RESULTS: The TGF-β and WNT pathways were associated with all CRC, and the WNT pathway was associated with colon cancer. Individual genes demonstrating the strongest associations were TGFBR2 in the TGF-β pathway and SMAD7 (which is involved in both the TGF-β and WNT pathways). As partial validation of our approach, a known CRC risk variant in SMAD7 (in both the TGF-β and WNT pathways: rs11874392) was associated with CRC risk in our data. We also detected two novel candidate CRC risk variants (rs13075948 and rs17025857) in TGFBR2, a gene known to be associated with CRC risk.
CONCLUSIONS: A stepwise, telescoping approach identified some potentially novel risk variants associated with colorectal cancer, so it may be a useful method for following up on results of set-based SNP analyses. Further work is required to assess the statistical characteristics of the approach, and additional applications should aid in better clarifying its utility.

Mota MSV, Jackson WP, Bailey SK, et al.
Deficiency of tumor suppressor Merlin facilitates metabolic adaptation by co-operative engagement of SMAD-Hippo signaling in breast cancer.
Carcinogenesis. 2018; 39(9):1165-1175 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
The NF2 gene encodes the tumor and metastasis suppressor protein Merlin. Merlin exerts its tumor suppressive role by inhibiting proliferation and inducing contact-growth inhibition and apoptosis. In the current investigation, we determined that loss of Merlin in breast cancer tissues is concordant with the loss of the inhibitory SMAD, SMAD7, of the TGF-β pathway. This was reflected as dysregulated activation of TGF-β signaling that co-operatively engaged with effectors of the Hippo pathway (YAP/TAZ/TEAD). As a consequence, the loss of Merlin in breast cancer resulted in a significant metabolic and bioenergetic adaptation of cells characterized by increased aerobic glycolysis and decreased oxygen consumption. Mechanistically, we determined that the co-operative activity of the Hippo and TGF-β transcription effectors caused upregulation of the long non-coding RNA Urothelial Cancer-Associated 1 (UCA1) that disengaged Merlin's check on STAT3 activity. The consequent upregulation of Hexokinase 2 (HK2) enabled a metabolic shift towards aerobic glycolysis. In fact, Merlin deficiency engendered cellular dependence on this metabolic adaptation, endorsing a critical role for Merlin in regulating cellular metabolism. This is the first report of Merlin functioning as a molecular restraint on cellular metabolism. Thus, breast cancer patients whose tumors demonstrate concordant loss of Merlin and SMAD7 may benefit from an approach of incorporating STAT3 inhibitors.

Abudureheman A, Ainiwaer J, Hou Z, et al.
High MLL2 expression predicts poor prognosis and promotes tumor progression by inducing EMT in esophageal squamous cell carcinoma.
J Cancer Res Clin Oncol. 2018; 144(6):1025-1035 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
BACKGROUND: MLL2 has been identified as one of the most frequently mutated genes in a variety of cancers including esophageal squamous cell carcinoma (ESCC). However, its clinical significance and prognostic value in ESCC has not been elucidated. In the present study, we aimed to investigate the expression and role of MLL2 in ESCC.
METHODS: Immunohistochemistry (IHC) and qRT-PCR were used to examine the expression profile of MLL2. Kaplan-Meier survival analysis and univariate and multivariate Cox analyses were used to investigate the clinical and prognostic significance of MLL2 expression in Kazakh ESCC patients. Furthermore, to evaluate the biological function of MLL2 in ESCC, we applied the latest gene editing technique CRISPR/Cas9 to knockout MLL2 in ESCC cell line Eca109. MTT, colony formation, flow cytometry, scratch wound-healing and transwell migration assays were performed to investigate the effect of MLL2 on ESCC cell proliferation and migration. The correlation between MLL2 and epithelial-mesenchymal transition (EMT) was investigated by Western blot assay in vitro and IHC in ESCC tissue, respectively.
RESULTS: Both mRNA and protein expression levels of MLL2 were significantly overexpressed in ESCC patients. High expression of MLL2 was significantly correlated with TNM stage (P = 0.037), tumor differentiation (P = 0.032) and tumor size (P = 0.035). Kaplan-Meier survival analysis showed that patients with low MLL2 expression had a better overall survival than those with high MLL2 expression. Multivariate Cox analysis revealed that lymph node metastasis and tumor differentiation were independent prognostic factors. Knockout of MLL2 in Eca109 inhibited cell proliferation and migration ability, induced cell cycle arrest at G1 stage, but it had no significant effect on apoptosis. In addition, knockout of MLL2 could inhibit EMT by up-regulation of E-Cadherin and Smad7 as well as down-regulation of Vimentin and p-Smad2/3 in ESCC cells. In cancer tissues, the expression of E-Cadherin was negatively correlated with MLL2 expression while Vimentin expression was positively correlated with MLL2 expression.
CONCLUSION: Our results indicate that overexpression of MLL2 predicts poor clinical outcomes and facilitates ESCC tumor progression, and it may exert oncogenic role via activation of EMT. MLL2 may be used as a novel prognostic factor and therapeutic target for ESCC patients.

Wang R, Fu T, You K, et al.
Identification of a TGF-β-miR-195 positive feedback loop in hepatocytes and its deregulation in hepatoma cells.
FASEB J. 2018; 32(7):3936-3945 [PubMed] Related Publications
Resistance to TGF-β-induced growth repression is prevalent in various cancer cells, but the underlying mechanisms remain unclear. In this study, we showed that activation of TGF-β signaling caused Sma- and Mad-related family (Smad) 2 and Smad3 to bind directly to the promoter region of miR-195, and then activated miR-195 transcription in normal hepatocytes. Conversely, miR-195 inhibited the expression of Smad7 by binding to its 3'-UTR, thereby strengthening TGF-β-Smad signaling. These data identify a novel TGF-β-miR-195 positive regulatory circuitry in normal hepatocytes. Further investigation revealed that HDAC1, a histone deacetylase that was abnormally overexpressed in hepatocellular carcinoma, could bind to the miR-195 promoter via Smad3 and cause hypoacetylation in the histones associated with the miR-195 promoter in hepatoma cells. This resulted in transcriptional repression of miR-195 and, subsequently, disruption of the TGF-β-miR-195 regulatory loop and evasion of TGF-β-mediated growth inhibition. Moreover, silencing HDAC1 in hepatoma cells restored TGF-β-mediated growth suppression, but this effect was attenuated if miR-195 expression decreased. These findings suggest that HDAC1-induced miR-195 down-regulation is an important mechanism for tumor cells to resist the cytostatic activity of TGF-β, and highlight the importance of TGF-β-Smad2/3-miR-195-Smad7 circuitry in preventing uncontrolled cell proliferation.-Wang, R., Fu, T., You, K., Li, S., Zhao, N., Yang, J., Zhuang, S.-M. Identification of a TGF-β-miR-195 positive feedback loop in hepatocytes and its deregulation in hepatoma cells.

Fedorova MS, Snezhkina AV, Pudova EA, et al.
Upregulation of NETO2 gene in colorectal cancer.
BMC Genet. 2017; 18(Suppl 1):117 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
BACKGROUND: Neuropilin and tolloid-like 2 (NETO2) is a single-pass transmembrane protein that has been shown primarily implicated in neuron-specific processes. Upregulation of NETO2 gene was also detected in several cancer types. In colorectal cancer (CRC), it was associated with tumor progression, invasion, and metastasis, and seems to be involved in epithelial-mesenchymal transition (EMT). However, the mechanism of NETO2 action is still poorly understood.
RESULTS: We have revealed significant increase in the expression of NETO2 gene and deregulation of eight EMT-related genes in CRC. Four of them were upregulated (TWIST1, SNAIL1, LEF1, and FOXA2); the mRNA levels of other genes (FOXA1, BMP2, BMP5, and SMAD7) were decreased. Expression of NETO2 gene was weakly correlated with that of genes involved in the EMT process.
CONCLUSIONS: We found considerable NETO2 upregulation, but no significant correlation between the expression of NETO2 and EMT-related genes in CRC. Thus, NETO2 may be involved in CRC progression, but is not directly associated with EMT.

Zhao B, Lu YL, Yang Y, et al.
Overexpression of lncRNA ANRIL promoted the proliferation and migration of prostate cancer cells via regulating let-7a/TGF-β1/ Smad signaling pathway.
Cancer Biomark. 2018; 21(3):613-620 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
Long non-coding RNAs (lncRNAs) were playing critical roles in tumorigenesis. However, in prostate cancer, the roles and mechanisms of lncRNAs especially ANRIL were largely unknown. We investigated the effects of ANRIL on the proliferation and migration of prostate cancer cells using CCK-8 assay and Transwell migration assay. Real-time PCR and western blotting assays were used to analyze the levels of ANRIL, let-7a, TGF-β1, p-Smad2 and p-Smad7. Our results showed that ANRIL was significantly overexpressed in prostate cancer tissues compared with corresponding normal tissues. Knockdown of ANRIL significantly inhibited the proliferation and migration of prostate cancer LNCap, PC3 and DU145 cells. Knockdown of ANRIL significantly decreased the levels of TGF-β1 and p-Smad2, and increased the level of p-Smad7 in prostate cancer LNCap cells. We further found that knockdown of ANRIL significantly enhanced the expression of let-7a, and rescue experiment found that let-7a inhibitor recovered the suppressive effects of ANRIL silencing on the proliferation and migration of prostate cancer LNCap, PC3 and DU145 cells. And let-7a inhibitor recovered the suppressive effects of ANRIL silencing on the activity of TGF-β1/Smad signaling pathway in prostate cancer LNCap cells. Taken together, our findings indicated that overexpression of lncRNA ANRIL promoted the proliferation and migration of prostate cancer cells via regulating let-7a/TGF-β1/Smad signaling pathway.

Zhang Z, Fan Y, Xie F, et al.
Breast cancer metastasis suppressor OTUD1 deubiquitinates SMAD7.
Nat Commun. 2017; 8(1):2116 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
Metastasis is the main cause of death in cancer patients. TGF-β is pro-metastatic for malignant cancer cells. Here we report a loss-of-function screen in mice with metastasis as readout and identify OTUD1 as a metastasis-repressing factor. OTUD1-silenced cancer cells show mesenchymal and stem-cell-like characteristics. Further investigation reveals that OTUD1 directly deubiquitinates the TGF-β pathway inhibitor SMAD7 and prevents its degradation. Moreover, OTUD1 cleaves Lysine 33-linked poly-ubiquitin chains of SMAD7 Lysine 220, which exposes the SMAD7 PY motif, enabling SMURF2 binding and subsequent TβRI turnover at the cell surface. Importantly, OTUD1 is lost in multiple types of human cancers and loss of OTUD1 increases metastasis in intracardial xenograft and orthotopic transplantation models, and correlates with poor prognosis among breast cancer patients. High levels of OTUD1 inhibit cancer stemness and shut off metastasis. Thus, OTUD1 represses breast cancer metastasis by mitigating TGF-β-induced pro-oncogenic responses via deubiquitination of SMAD7.

Hu Y, Gaedcke J, Emons G, et al.
Colorectal cancer susceptibility loci as predictive markers of rectal cancer prognosis after surgery.
Genes Chromosomes Cancer. 2018; 57(3):140-149 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
To understand the molecular mechanism of rectal cancer and develop markers for disease prognostication, we generated and explored a dataset from 243 rectal cancer patients by gene expression microarray analysis of cancer samples and matched controls, and SNP-arrays of germline DNA. We found that two of the loci most strongly linked with colorectal cancer (CRC) risk, 8q24 (upstream of MYC) and 18q21 (in the intron of SMAD7), as well as 20q13 (in the intron of LAMA5), are tightly associated with the prognosis of rectal cancer patients. For SNPs on 18q21 (rs12953717 and rs4464148) and 20q13 (rs4925386), alleles that correlate with higher risk for the development of CRC are associated with shorter disease free survival (DFS). However, for rs6983267 on 8q24, the low risk allele is associated with a higher risk for recurrence and metastasis after surgery, and importantly, is strongly correlated with the resistance of CRC cell lines to chemoradiotherapy (CRT). We also found that although MYC expression is dramatically increased in cancer, patients with higher levels of MYC have a better prognosis. The expression of SMAD7 is weakly correlated with DFS. Notably, the presence of the 8q24 and 18q21 SNP alleles is not correlated with expression levels of MYC and SMAD7. rs4464148, and probably rs6983267 and rs4925386, are linked with overall survival time of patients. In conclusion, we show that several CRC risk SNPs detect subpopulations of rectal cancer patients with poor prognosis, and that rs6983267 probably affects prognosis through interfering with the resistance of cancer cells to CRT.

Naji M, Aleyasin A, Nekoonam S, et al.
Differential Expression of miR-93 and miR-21 in Granulosa Cells and Follicular Fluid of Polycystic Ovary Syndrome Associating with Different Phenotypes.
Sci Rep. 2017; 7(1):14671 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
The heterogeneous and multifactorial essence of polycystic ovary syndrome (PCOS) renders a remarkable significance to microRNAs (miRNAs). Normo-androgenic (NA) and hyperandrogenic (HA) PCOS patients were compared with matched healthy women. Expression of miRNAs and TGFβ signaling genes was studied by qRT-PCR and western blotting. Effect of androgen on expression of miR-93 and miR-21 and involvement of androgen receptor were appraised. In granulosa cells (GCs), miR-93 and miR-21 showed significantly increased levels in HA patients compared to NA patients. On the contrary, follicular fluid (FF) levels of both miRNAs were significantly decreased in HA group compared to control women. No significant change in the expression of miRNAs in serum samples was detected. Furthermore, mRNA levels of SMAD7 and TGFBR2 were significantly downregulated in GCs of HA group compared to NA and control subjects. TGFBR2 protein level was significantly decreased in HA patients compared to controls. Free testosterone and free androgen index were positively correlated with expression of miR-93 and miR-21 in GCs of PCOS group. Our findings show distinct molecular signature of different subtypes of PCOS. Intermediary position of miRNAs as androgen responsive factors may play critical role in the pathogenesis of PCOS in hyperandrogenic condition.

Alonso-Molero J, González-Donquiles C, Palazuelos C, et al.
The RS4939827 polymorphism in the SMAD7 GENE and its association with Mediterranean diet in colorectal carcinogenesis.
BMC Med Genet. 2017; 18(1):122 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
BACKGROUND: The objective of our investigation is to study the relationship between the rs4939827 SNP in the SMAD7 gene, Mediterranean diet pattern and the risk of colorectal cancer.
METHODS: We examined 1087 cases of colorectal cancer and 2409 population controls with available DNA samples from the MCC-Spain study, 2008-2012. Descriptive statistical analyses, and multivariate logistic mixed models were performed. The potential synergistic effect of rs4939827 and the Mediterranean diet pattern was evaluated with logistic regression in different strata of of adherence to the Mediterranean diet and the genotype.
RESULTS: High adherence to Mediterrenean diet was statistically significantly associated with colorectal cancer risk. A decreased risk for CRC cancer was observed for the CC compared to the TT genotype (OR = 0.65 and 95% CI = 0.51-0.81) of the rs4939827 SNP Also, we could show an association between the Mediterranean diet pattern (protective factor) and rs4939827. Although the decreased risk for the CC genotype was slightly more pronounced in subjects with high adherence to Mediterrenean diet, there was no statistically significant synergistic effect between genotype CC and adherence to the Mediterranean dietary pattern factors.
CONCLUSION: The SMAD7 gene and specifically the allele C could be protective for colorectal cancer. An independent protective association was also observed between high adherence Mediterranean diet pattern and CRC risk. Findings form this study indicate that high adherence to Mediterranean diet pattern has a protective role for CRC cancer probably involving the Tumor Growth Factor- β pathway in this cancer.

Schneiderova M, Naccarati A, Pardini B, et al.
MicroRNA-binding site polymorphisms in genes involved in colorectal cancer etiopathogenesis and their impact on disease prognosis.
Mutagenesis. 2017; 32(5):533-542 [PubMed] Related Publications
According to the Vogelstein's model of colorectal carcinogenesis, genetic variations in highly penetrant genes may be involved in the colorectal cancer (CRC) pathogenesis. Similarly, aberrant function and/or altered expression of microRNAs (miRNAs) often occur in CRC. In this context, polymorphisms in miRNA-binding sites (miRSNPs) may affect miRNA/target gene interaction, resulting in differential mRNA/protein expression and increased susceptibility to common diseases. To explore this phenomenon, we have mined the 3' untranslated regions (3'UTRs) of genes known to be frequently mutated in CRC to search for miRSNPs and tested their association with CRC risk and clinical outcome. Eight miRSNPs (rs1804191, rs397768, rs41116 in APC; rs1137918, s227091, rs4585 in ATM; rs712, rs1137282, rs61764370 in KRAS; rs8674 in PARP1 and rs16950113 in SMAD7) were tested for their association with CRC risk in a case-control study (1111 cases and 1469 healthy controls). The role of these miRSNPs was also investigated in relation to clinical outcome on a subset of patients with complete follow-up. rs8679 within PARP1 was associated with CRC risk and patients' survival. In the dominant model, carriers of at least one C allele were at a decreased risk of cancer (P = 0.05). The CC genotype in rs8679 was also associated with an increased risk of recurrence/progression in patients that received 5-FU-based chemotherapy (log-rank test P = 0.03). Carriers of the homozygous variant genotype TT for rs712 in KRAS gene were associated with a decreased risk of rectal cancer (odds ratio (OR) = 0.65, 95% confidence intervals (CI) 0.43-1.00, P = 0.05) while individuals with colon cancer carrying the heterozygous GT genotype showed a longer overall survival (OS) (P = 0.04). We provide the first evidence that variations in potential miRNA-binding target sites in the 3' UTR of PARP1 gene may modulate CRC risk and prognosis after therapy. Further studies are needed to replicate our finding and assess miRSNPs as predictive biomarkers in independent populations.

Moon H, Ju HL, Chung SI, et al.
Transforming Growth Factor-β Promotes Liver Tumorigenesis in Mice via Up-regulation of Snail.
Gastroenterology. 2017; 153(5):1378-1391.e6 [PubMed] Related Publications
BACKGROUND & AIMS: Transforming growth factor beta (TGF-β) suppresses early stages of tumorigenesis, but also contributes to migration and metastasis of cancer cells. A large number of human tumors contain mutations that inactivate its receptors, or downstream proteins such as Smad transcription factors, indicating that the TGF-β signaling pathway prevents tumor growth. We investigated the effects of TGF-β inhibition on liver tumorigenesis in mice.
METHODS: C57BL/6 mice received hydrodynamic tail-vein injections of transposons encoding HRAS
RESULTS: TGF-β inhibition via overexpression of SMAD7 (or knockdown of SMAD2, SMAD3, or SMAD4) consistently reduced formation and growth of liver tumors in mice that expressed activated RAS plus shRNA against p53, or in mice that expressed activated RAS and TAZ. TGF-β signaling activated transcription of the Snail gene in liver tumors induced by HRAS
CONCLUSIONS: In analyses of transgenic mice, we found TGF-β signaling to be required for formation of liver tumors upon expression of activated RAS and shRNA down-regulating p53, and upon expression of activated RAS and TAZ. Snail is the TGF-β target that is required for hepatic tumorigenesis in these models.

Jiao W, Leng X, Zhou Q, et al.
Different miR-21-3p isoforms and their different features in colorectal cancer.
Int J Cancer. 2017; 141(10):2103-2111 [PubMed] Related Publications
MiR-21, the only microRNA (miRNA) found to be overexpressed in any type of solid tumor, its guide stand, miR-21-5p, has been studied a lot in colorectal cancer (CRC); however, few researchers focused on its passenger strand, miR-21-3p. In our study, based on The Cancer Genome Atlas (TCGA) data, we found that there were more varieties and quantities of miR-21-3p isoforms in microsatellite instability (MSI)-type CRC. We further examined the role of miR-21-3p by in vitro and in vivo studies. MiR-21-3p may be an oncogene in CRC by promoting cellular mobility through epithelial-mesenchymal transition. However, different isoforms, especially miR-21-3p 0 | 2, may be a favorable prognostic marker for CRC survival, probably due to increased complementary effect of miR-21-5p and/or target genes. Further study investigating the underlying mechanism of miRNA isoforms is needed.

Nabhan M, Louka ML, Khairy E, et al.
MicroRNA-181a and its target Smad 7 as potential biomarkers for tracking child acute lymphoblastic leukemia.
Gene. 2017; 628:253-258 [PubMed] Related Publications
Acute lymphoblastic leukemia (ALL) is the most common pediatric hematologic tumor. MiR-181a was expected to have a role in the development of hematological malignancies; it might act as tumor suppressor or oncogene. Smad7 was selected as miR-181a target pair. It is a negative regulator for the TGF-β1 signaling pathway. In this study, relative expression levels of miR-181a by quantitative reverse transcriptase polymerase chain reaction (qRT-PCR), both Smad 7 and TGF-β1 proteins levels by enzyme linked immunosorbent assay (ELISA) were all measured in serum of 60 child, 30 with ALL and 30 age and sex matched healthy child as control group. MiR-181a expression showed highly significant decrease; plus a significant increase and decrease of Smad7 and TGF-β1 protein levels respectively, in serum samples of ALL as compared to control group. MiR-181a expression achieved a highly significant positive and a significant negative correlation with TGF-β1 and Smad7 respectively. Furthermore, the levels of Smad7 and TGF-β1 were negatively correlated with each other (p<0.05). Although, positivity rate of both Smad7 and TGF-β1 in ALL group increased with presence of hepatosplenomegaly, still there was no statistical significance. In conclusion, miR-181a could act as a tumor suppressor in pediatric ALL with over expression of its target pair, Smad7. Smad7 regulates TGF-β1 signaling via a negative feedback loop and mediates the interaction between TGF-β1 and other signaling pathways; suggesting that Smad7 over expression may have therapeutic potential in ALL.

Ayub SG, Kaul D
miR-2909 regulates ISGylation system via STAT1 signalling through negative regulation of SOCS3 in prostate cancer.
Andrology. 2017; 5(4):790-797 [PubMed] Related Publications
One of the well-document strategies adopted by tumour cells for progression is to evade immune surveillance mechanisms. An understanding of the tight interaction between immunity and progression of cancer can provide novel treatment options for different malignancies including prostate cancer (PCa). Here, we have shown that AATF genome encoded miR-2909, known to play role both in immunity and cancer upregulates various interferon stimulating genes (ISGs) including ISGylation system through STAT1. Our results revealed that miR-2909 up-regulates STAT1 through negative regulation of SOCS3 and not through up-regulation of Type 1 interferon (IFN) production. It was observed that inhibition of ISGylation reduced the proliferation potential of PCa cells. Furthermore, androgens were found to negatively regulate ISGylation in LNCaP cells through androgen receptor signalling independently of miR-2909. TGF-β mediated SMAD3 signalling was also seen to be suppressed by miR-2909 through induction of SMAD7 via enhanced STAT1 expression. Collectively, these studies suggest that miR-2909 could play a vital role in prostate carcinogenesis through modulation of ISGylation system and TGFβ signalling via STAT1.

Wang Y
The inhibition of microRNA-15a suppresses hepatitis B virus-associated liver cancer cell growth through the Smad/TGF-β pathway.
Oncol Rep. 2017; 37(6):3520-3526 [PubMed] Related Publications
In the present study, the role of microRNA‑15a (miR‑15a) was investigated in hepatitis B virus (HBV)‑associated liver cancer. The results revealed that the expression levels of miR-15a were increased in HBV-associated liver cancer tissues compared with the levels in normal tumor‑adjacent tissues. Moreover, Smad-7 protein expression in patients with HBV-associated liver cancer was higher than that in normal tumor-adjacent tissues. In addition, miR-15a expression and Smad-7 protein expression were increased in HepG2 hepatocellular carcinoma cells compared with that noted in L-02 normal hepatocytes. In HepG2 cells, miR-15a inhibition suppressed cell proliferation and increased Smad-7 protein expression. The inhibition of miR-15a was also demonstrated to decrease transforming growth factor (TGF)-β1 protein expression and Smad-2, p-Smad-2 and Smad-4 expression levels in HepG2 cells. Furthermore, FSP1 protein expression and caspase-3/-7 activities were enhanced by miR-15a inhibition in HepG2 cells compared with the control group. Treatment with recombinant TGF-β1 was demonstrated to activate Smad‑2/-4 and FSP1 protein expression and increase caspase-3/-7 activity in HepG2 cells. Collectively, these findings demonstrate that the miR-15a/Smad-7/TGF-β pathway is important in HBV-associated liver cancer.

Said HM, Safari R, Al-Kafaji G, et al.
Time- and oxygen-dependent expression and regulation of NDRG1 in human brain cancer cells.
Oncol Rep. 2017; 37(6):3625-3634 [PubMed] Related Publications
N-myc downstream-regulated gene 1 (NDRG1) is a tumor suppressor with the potential to suppress metastasis, invasion and migration of cancer cells. It is regulated under stress conditions such as starvation or hypoxia. NDRG1 regulation is both induced and controlled by HIF-1α-dependent and -independent pathways under hypoxic conditions. However, there are profound differences in the way NDRG1 expression is regulated by HIF-1α and other transcription factors. Therefore, we aimed to define the time-dependent pattern of NDRG1 mRNA and protein expression in human glioblastoma cell lines in extreme hypoxia and after re-oxygenation as well as under normoxic conditions. Furthermore, we ascribe the regulation of NDRG1 to the transcription factors HIF-1α, SP1, CEBPα, YB-1 and Smad7 in a time-dependent manner. The human malignant glioma cell lines U87-MG, U373 and GaMG were cultured for 1, 6 and 24 h under hypoxic (0.1% O2) conditions and then they were re-oxygenated. The mRNA expression of NDRG1, HIF-1α SP1, CEBPα, YB-1 and Smad7 was measured using semi-quantitative RT-PCR analysis. Their protein expression was analyzed using western blotting. Our experiments revealed that long-term (24 h), but not short-term hypoxia led to the induction of NDRG1 expression in human glioma cell lines. NDRG1 expression was found to correlate with the protein expression of HIF-1α, SP1, CEBPα, YB-1 and Smad7. The present study suggests for the first time that SP1 regulates NDRG1 expression in glioma cells under hypoxia in a time-dependent manner along with HIF-1α, CEBPα, YB-1 and Smad7. These molecules, each separately or in combination, may possess the potential to become target molecules for antitumor therapeutic approaches particularly in human brain tumors.

Zhang C, Li X, Fu W, et al.
SMAD7 rs4939827 variant contributes to colorectal cancer risk in Chinese population.
Oncotarget. 2017; 8(25):41125-41131 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
A genome-wide association study identified a common genetic variant rs4939827 at 18q21 in SMAD7 to be related with colorectal cancer (CRC) risk with OR=1.2 and P =7.80E-28. Until recently, several meta-analysis studies have been conducted, and reported significant association between rs4939827 and CRC risk. However none of these studies evaluated the potential association between rs4939827 and CRC risk in Chinese population. In this study, we evaluated this association by a meta-analysis using 12077 samples including 5816 CRC cases and 6261 controls. In the end, we identified the T allele of rs4939827 to be significantly related with an increase CRC risk (P=2.22E-05, OR=1.14, 95% CI 1.07-1.21) in Chinese population.

Wu RS, Hong JJ, Wu JF, et al.
OVOL2 antagonizes TGF-β signaling to regulate epithelial to mesenchymal transition during mammary tumor metastasis.
Oncotarget. 2017; 8(24):39401-39416 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
Great progress has been achieved in the study of the role of TGF-β signaling in triggering epithelial-mesenchymal transition (EMT) in a variety of cancers; however, the regulation of TGF-β signaling during EMT in mammary tumor metastasis has not been completely defined. In the present study, we demonstrated that OVOL2, a zinc finger transcription factor, inhibits TGF-β signaling-induced EMT in mouse and human mammary tumor cells, as well as in mouse tumor models. Data from the Oncomine databases indicated a strong negative relationship between OVOL2 expression and breast cancer progression. Moreover, our experiments revealed that OVOL2 inhibits TGF-β signaling at multiple levels, including inhibiting Smad4 mRNA expression and inducing Smad7 mRNA expression, blocking the binding between Smad4 and target DNA, and interfering with complex formation between Smad4 and Smad2/3. These findings reveal a novel mechanism that controls the TGF-β signaling output level in vitro and in vivo. The modulation of these molecular processes may represent a strategy for inhibiting breast cancer invasion by restoring OVOL2 expression.

Ratz L, Laible M, Kacprzyk LA, et al.
TMPRSS2:ERG gene fusion variants induce TGF-β signaling and epithelial to mesenchymal transition in human prostate cancer cells.
Oncotarget. 2017; 8(15):25115-25130 [PubMed] Article available free on PMC after 21/09/2019 Related Publications
TMPRSS2:ERG (T/E) gene fusions are present in approximately 50% of all prostate cancer (PCa) cases. The expression of fusion mRNAs from distinct T/E variants is associated with clinicopathological parameters, while the underlying molecular processes remain unclear. We characterized the molecular mechanisms and functional implications caused by doxycycline (Dox)-inducible overexpression of the frequent T/E III and VI fusion variants in LNCaP cells. Induction of T/E expression resulted in increased cellular migratory and invasive potential, and reduced proliferation and accumulation in G1 phase. T/E overexpressing cells showed epithelial-to-mesenchymal transition (EMT), as demonstrated by upregulation of TGF-β and WNT pathway genes, mesenchymal markers, and increased phosphorylation of the p38 MAPK. Augmented secretion of TGF-β1 and -β2, and T/E-mediated regulation of ALK1, a member of the TGF-β receptor family, was detected. ALK1 inhibition in T/E overexpressing cells blocked p38 phosphorylation and reduced the expression of the TGF-β target genes VIM, MMP1, CDH2, and SNAI2. We found a T/E variant VI-specific induction of miR-503 associated with reduced expression of SMAD7 and CDH1. Overexpression of miR-503 led to increased levels of VIM and MMP1. Our findings indicate that TGF-β signaling is a major determinant of EMT in T/E overexpressing LNCaP cells. We provide evidence that T/E VI-specific transcriptional modulation by miR-503 accounts for differences in the activation of EMT pathway genes, promoting the aggressive phenotype of tumors expressing T/E variant VI. We suggest that ALK1-mediated TGF-β signaling is a novel oncogenic mechanism in T/E positive PCa.

Gen Y, Yasui K, Kitaichi T, et al.
ASPP2 suppresses invasion and TGF-β1-induced epithelial-mesenchymal transition by inhibiting Smad7 degradation mediated by E3 ubiquitin ligase ITCH in gastric cancer.
Cancer Lett. 2017; 398:52-61 [PubMed] Related Publications
ASPP2 regulates cell polarity and cell-cell adhesion by binding to, and co-localizing with PAR3 at tight junctions. Here we show a novel role of ASPP2 in suppressing gastric cancer (GC) invasiveness. Immunoprecipitation and immunofluorescence analyses showed that ASPP2 promoted the recruitment of PAR3 to cell-cell junctions in GC cells. Diminished expression of ASPP2 and loss of junctional PAR3 localization were significantly associated with diffuse-type histology, deeper invasion depth, positive peritoneal dissemination and worse prognosis in primary GC. ASPP2 suppressed migration and invasion of GC cells in vitro and peritoneal dissemination of GC cells in vivo in a mouse model. ASPP2 suppressed epithelial-mesenchymal transition (EMT) induced by TGF-β1-Smad2/3 signaling in GC cells through suppression of the degradation of Smad7, a negative regulator of TGF-β1-Smad2/3 signaling, by interacting with the E3 ubiquitin ligase ITCH. In conclusion, ASPP2 suppresses invasion, peritoneal dissemination and TGF-β1-induced EMT by inhibiting Smad7 degradation mediated by ITCH.

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