SMAD5

Gene Summary

Gene:SMAD5; SMAD family member 5
Aliases: DWFC, JV5-1, MADH5
Location:5q31.1
Summary:The protein encoded by this gene is involved in the transforming growth factor beta signaling pathway that results in an inhibition of the proliferation of hematopoietic progenitor cells. The encoded protein is activated by bone morphogenetic proteins type 1 receptor kinase, and may be involved in cancer. Alternative splicing results in multiple transcript variants. [provided by RefSeq, Feb 2014]
Databases:VEGA, OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:mothers against decapentaplegic homolog 5
Source:NCBIAccessed: 16 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 16 March 2017 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 16 March, 2017 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: SMAD5 (cancer-related)

Xie K, Ma H, Liang C, et al.
A functional variant in miR-155 regulation region contributes to lung cancer risk and survival.
Oncotarget. 2015; 6(40):42781-92 [PubMed] Free Access to Full Article Related Publications
Emerging evidence suggested that upregulation of miR-155 could serve as a promising marker for the diagnosis and prognosis of non-small cell lung cancer (NSCLC). In the present study, we genotyped rs767649 (A > T) located in miR-155 regulation region in 1341 cases and 1982 controls, and analyzed the associations of rs767649 with NSCLC risk and survival. Consequently, rs767649 exhibited the significant associations with the risk (adjusted OR = 1.12, 95% CI = 1.01-1.24, P = 0.031) and prognosis of NSCLC (adjusted HR = 1.17, 95% CI = 1.03-1.32, P = 0.014). Meanwhile, rs767649 specifically interacted with radio-chemotherapy (P(int) = 0.013), and patients with both the rs767649-TT genotype and radio-chemotherapy had the highest hazard ratio (adjusted HR = 1.65, 95% CI = 1.26-2.16, P < 0.001). Furthermore, using functional assays and The Cancer Genome Atlas (TCGA) Lung Adenocarcinoma (LUAD) dataset, we found that rs767649 variant allele could increase the transcriptional activity of miR-155, which in turn facilitated tumor growth and metastasis by inhibiting HBP1, TJP1, SMAD5 and PRKAR1A expression. Our findings suggested that rs767649 A > T might contribute to the increased risk and poor prognosis of NSCLC, highlighting the importance of rs767649 in the prevention and therapy of NSCLC.

Lulli V, Buccarelli M, Martini M, et al.
miR-135b suppresses tumorigenesis in glioblastoma stem-like cells impairing proliferation, migration and self-renewal.
Oncotarget. 2015; 6(35):37241-56 [PubMed] Free Access to Full Article Related Publications
Glioblastoma multiforme (GBM) is the most common and fatal malignant adult primary brain tumor. Currently, the overall prognosis for GBM patients remains poor despite advances in neurosurgery and adjuvant treatments. MicroRNAs (miRNAs) contribute to the pathogenesis of various types of tumor, including GBM. In this study we analyzed the expression of a panel of miRNAs, which are known to be differentially expressed by the brain and GBM tumor, in a collection of patient-derived GBM stem-like cells (GSCs). Notably, the average expression level of miR-135b, was the most downregulated compared to its normal counterpart, suggesting a potential role as anti-oncogene.Restoration of miR-135b in GSCs significantly decreased proliferation, migration and clonogenic abilities. More importantly, miR-135b restoration was able to significantly reduce brain infiltration in mouse models of GBM obtained by intracerebral injection of GSC lines. We identified ADAM12 and confirmed SMAD5 and GSK3β as miR-135b targets and potential mediators of its effects. The whole transcriptome analysis ascertained that the expression of miR-135b downmodulated additional genes driving key pathways in GBM survival and infiltration capabilities.Our results identify a critical role of miR-135b in the regulation of GBM development, suggesting that miR-135b might act as a tumor-suppressor factor and thus providing a potential candidate for the treatment of GBM patients.

Zhang X, Ai F, Li X, et al.
Inflammation-induced S100A8 activates Id3 and promotes colorectal tumorigenesis.
Int J Cancer. 2015; 137(12):2803-14 [PubMed] Related Publications
The aberrant expression of S100A8 and S100A9 is linked to nonresolving inflammation and ultimately to carcinogenesis, whereas the underlying mechanism that allows inflammation to progress to specific cancer types remains unknown. Here, we report that S100A8 was induced by inflammation and then promoted colorectal tumorigenesis downstream by activating Id3 (inhibitor of differentiation 3). Using gene expression profiling and immunohistochemistry, we found that both S100A8 and S100A9 were upregulated in the chemically-induced colitis-associated cancer mouse model and in human colorectal cancer specimens. Furthermore, we showed that S100A8 and S100A9 acted as chemoattractant proteins by recruiting macrophages, promoting the proliferation and invasion of colon cancer cell, as well as spurring the cycle that culminates in the acceleration of cancer metastasis in a nude mouse model. S100A8 regulated colon cancer cell cycle and proliferation by inducing Id3 expression while inhibiting p21. Id3 expression was regulated by Smad5, which was directly phosphorylated by Akt1. Our study revealed a novel mechanism in which inflammation-induced S100A8 promoted colorectal tumorigenesis by acting upstream to activate the Akt1-Smad5-Id3 axis.

Zhao YG, Shi BY, Qian YY, et al.
Dynamic expression changes between non-muscle-invasive bladder cancer and muscle-invasive bladder cancer.
Tumori. 2014 Nov-Dec; 100(6):e273-81 [PubMed] Related Publications
AIMS AND BACKGROUND: Despite elaborate characterization of the risk factors, bladder cancer is still a major epidemiological problem whose incidence continues to rise each year. We aim to investigate the dynamic expression changes between non-muscle-invasive bladder cancer (NMIBC) and muscle-invasive bladder cancer (MIBC).
METHODS: The gene expression profile GSE13507 was obtained from the Gene Expression Omnibus, and the R package was used to identify gene expression signatures (GESs) between NMIBC and MIBC. Gene ontology enrichment analysis was performed for GES function analysis. We used miRTarBase and TargetScan to identify the differentially regulated microRNAs, and TfactS to identify transcription factors between NMIBC and MIBC. Bionet was used to identify the differentially expressed subnetwork.
RESULTS: A total of 802 upregulated NMIBC GESs and 668 downregulated MIBC GESs were identified. Functional enrichment analysis revealed that the MIBC GESs were majorly involved in cell cycle and inflammatory response. miR-29c and miR-9 were regarded as key microRNAs in MIBC. SMAD3 in MIBC and SMAD5 and SMAD7 in NMIBC were potential activated transcription factors. In addition, a subnetwork that was considered to capture the differences between MIBC and NMIBC was identified, of which GRB2 and UBC were the hub nodes.
CONCLUSIONS: Some key microRNAs, activated transcription factors and hub nodes have been identified in this study, which may be used as potential biomarkers or targets for the diagnosis, treatment and detection of bladder cancer at different stages.

Seystahl K, Tritschler I, Szabo E, et al.
Differential regulation of TGF-β-induced, ALK-5-mediated VEGF release by SMAD2/3 versus SMAD1/5/8 signaling in glioblastoma.
Neuro Oncol. 2015; 17(2):254-65 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: The transforming growth factor (TGF)-β and vascular endothelial growth factor (VEGF) pathways have a major role in the pathogenesis of glioblastoma, notably immunosuppression, migration, and angiogenesis, but their interactions have remained poorly understood.
METHODS: We characterized TGF-β pathway activity in 9 long-term glioma cell lines (LTCs) and 4 glioma-initiating cell lines (GICs) in relation to constitutive and exogenous TGF-β-induced VEGF release. Results were validated using The Cancer Genome Atlas transcriptomics data.
RESULTS: Glioma cells exhibit heterogeneous patterns of constitutive TGF-β pathway activation reflected by phosphorylation not only of SMAD2 and SMAD3 but also of SMAD1/5/8. Constitutive TGF-β pathway activity depends on the type I TGF-β receptor, ALK-5, and accounts for up to 69% of constitutive VEGF release, which is positively regulated by SMAD2/3 and negatively regulated by SMAD1/5/8 signaling in a cell line-specific manner. Exogenous TGF-β induces VEGF release in most cell lines in a SMAD- and ALK-5-dependent manner. There is no correlation between the fold induction of VEGF secretion induced by TGF-β compared with hypoxia. The role of SMAD5 signaling is highly context and cell-line dependent with a VEGF inhibitory effect at low TGF-β and pSMAD2 levels and a stimulatory effect when TGF-β is abundant.
CONCLUSIONS: TGF-β regulates VEGF release by glioma cells in an ALK-5-dependent manner involving SMAD2, SMAD3, and SMAD1/5/8 signaling. This crosstalk between the TGF-β and VEGF pathways may open up new avenues of biomarker-driven exploratory clinical trials focusing on the microenvironment in glioblastoma.

Mansouri-Attia N, James R, Ligon A, et al.
Soy promotes juvenile granulosa cell tumor development in mice and in the human granulosa cell tumor-derived COV434 cell line.
Biol Reprod. 2014; 91(4):100 [PubMed] Free Access to Full Article Related Publications
Soy attracts attention for its health benefits, such as lowering cholesterol or preventing breast and colon cancer. Soybeans contain isoflavones, which act as phytoestrogens. Even though isoflavones have beneficial health effects, a role for isoflavones in the initiation and progression of diseases including cancer is becoming increasingly recognized. While data from rodent studies suggest that neonatal exposure to genistein (the predominant isoflavone in soy) disrupts normal reproductive function, its role in ovarian cancers, particularly granulosa cell tumors (GCT), is largely unknown. Our study aimed to define the contribution of a soy diet in GCT development using a genetically modified mouse model for juvenile GCTs (JGCT; Smad1 Smad5 conditional double knockout mice) as well as a human JGCT cell line (COV434). While dietary soy cannot initiate JGCT development in mice, we show that it has dramatic effects on GCT growth and tumor progression compared to a soy-free diet. Loss of Smad1 and Smad5 alters estrogen receptor alpha (Esr1) expression in granulosa cells, perhaps sensitizing the cells to the effects of genistein. In addition, we found that genistein modulates estrogen receptor expression in the human JGCT cell line and positively promotes cell growth in part by suppressing caspase-dependent apoptosis. Combined, our work suggests that dietary soy consumption has deleterious effects on GCT development.

Fontebasso AM, Papillon-Cavanagh S, Schwartzentruber J, et al.
Recurrent somatic mutations in ACVR1 in pediatric midline high-grade astrocytoma.
Nat Genet. 2014; 46(5):462-6 [PubMed] Free Access to Full Article Related Publications
Pediatric midline high-grade astrocytomas (mHGAs) are incurable with few treatment targets identified. Most tumors harbor mutations encoding p.Lys27Met in histone H3 variants. In 40 treatment-naive mHGAs, 39 analyzed by whole-exome sequencing, we find additional somatic mutations specific to tumor location. Gain-of-function mutations in ACVR1 occur in tumors of the pons in conjunction with histone H3.1 p.Lys27Met substitution, whereas FGFR1 mutations or fusions occur in thalamic tumors associated with histone H3.3 p.Lys27Met substitution. Hyperactivation of the bone morphogenetic protein (BMP)-ACVR1 developmental pathway in mHGAs harboring ACVR1 mutations led to increased levels of phosphorylated SMAD1, SMAD5 and SMAD8 and upregulation of BMP downstream early-response genes in tumor cells. Global DNA methylation profiles were significantly associated with the p.Lys27Met alteration, regardless of the mutant histone H3 variant and irrespective of tumor location, supporting the role of this substitution in driving the epigenetic phenotype. This work considerably expands the number of potential treatment targets and further justifies pretreatment biopsy in pediatric mHGA as a means to orient therapeutic efforts in this disease.

Lee GT, Kang DI, Ha YS, et al.
Prostate cancer bone metastases acquire resistance to androgen deprivation via WNT5A-mediated BMP-6 induction.
Br J Cancer. 2014; 110(6):1634-44 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Androgen ablation is the first-line therapy for patients with metastatic prostate cancer (CaP). However, castration resistance will eventually emerge. In the present study, we have investigated the role of bone morphogenetic protein-6 (BMP-6) in the development of castration-resistant prostate cancer (CRPC) in the context of bone metastases.
METHODS: We initially investigated the clinical course of 158 men with advanced CaP who were treated with primary androgen deprivation therapy. To elucidate the underlying mechanism of CRPC in the context of bone metastases, we examined the impact of bone stromal cells on CaP in the absence of androgens using a co-culture model.
RESULTS: In the 158 patients, we found that the median time to prostate-specific antigen progression was significantly shorter when bone metastases were present (14 months (95% CI, 10.2-17.8 months) vs 57 months (95% CI, 19.4-94.6 months)). These results suggest that bone-tumour interactions may accelerate castration resistance. Consistent with this hypothesis, in vitro co-cultures demonstrated that CaP cells proliferated under an androgen-depleted condition when incubated with bone stromal cells. Mechanistically, gene expression analysis using quantitative polymerase chain reaction arrays showed a dramatic induction of BMP-6 by CaP cell lines in the presence of bone stromal cells. Further studies revealed that WNT5A derived from bone stromal cells induced the expression of BMP-6 by CaP cells; BMP-6 in turn stimulated cellular proliferation of CaP cells in an androgen-deprived media via a physical interaction between Smad5 and β-catenin. Intracellularly, WNT5A increased BMP-6 expression via protein kinase C/NF-κB pathway in CaP cell lines.
CONCLUSIONS: These observations suggest that bone-CaP interaction leads to castration resistance via WNT5A/BMP-6 loop.

Cho H, Kim S, Shin HY, et al.
Expression of stress-induced phosphoprotein1 (STIP1) is associated with tumor progression and poor prognosis in epithelial ovarian cancer.
Genes Chromosomes Cancer. 2014; 53(4):277-88 [PubMed] Related Publications
Stress-induced phosphoprotein1 (STIP1) is a candidate biomarker in epithelial ovarian cancer (EOC). In this study, we investigated in detail the expression of STIP1, as well as its functions, in EOC. STIP1 expression was assessed by immunohistochemistry (IHC) and the results were compared with clinicopathologic factors, including survival data. The effects of STIP1 gene silencing via small interfering RNA (siRNA) were examined in EOC cells and a xenograft model. The expression of STIP1 protein in EOC was significantly higher than in the other study groups (P < 0.001), and this increase of expression was significantly associated with tumor stage (P = 0.005), tumor grade (P = 0.029), and lymph node metastasis (P = 0.020). In multivariate analysis, overall survival in EOC was significantly shorter in cases with high STIP1 expression (HR = 2.78 [1.01-7.63], P = 0.047). STIP1 silencing in EOC cells resulted in inhibition of cell proliferation and invasion. In addition, in vivo experiments using STIP1 siRNA clearly showed a strong inhibition of tumor growth and a modulation of expression of prosurvival and apoptotic genes, further suggesting that STIP1 silencing can prevent cell proliferation and invasion. In conclusion, increased STIP1 expression is associated with poor survival outcome in EOC, and STIP1 may represent a useful therapeutic target in EOC patients.

Xu S, Cecilia Santini G, De Veirman K, et al.
Upregulation of miR-135b is involved in the impaired osteogenic differentiation of mesenchymal stem cells derived from multiple myeloma patients.
PLoS One. 2013; 8(11):e79752 [PubMed] Free Access to Full Article Related Publications
Previous studies have demonstrated that mesenchymal stem cells from multiple myeloma (MM) patients (MM-hMSCs) display a distinctive gene expression profile, an enhanced production of cytokines and an impaired osteogenic differentiation ability compared to normal donors (ND-hMSCs). However, the underlying molecular mechanisms are unclear. In the present study, we observed that MM-hMSCs exhibited an abnormal upregulation of miR-135b, showing meanwhile an impaired osteogenic differentiation and a decrease of SMAD5 expression, which is the target of miR-135b involved in osteogenesis. By gain and loss of function studies we confirmed that miR-135b negatively regulated hMSCs osteogenesis. We also found that MM cell-produced factors stimulated ND-hMSCs to upregulate the expression of miR-135b. Importantly, treatment with a miR-135b inhibitor promoted osteogenic differentiation in MM-hMSCs. Finally, we observed that MM cell-derived soluble factors could induce an upregulation of miR-135b expression in ND-hMSCs in an indirect coculture system and the miR-135b expression turned to normal level after the removal of MM cells. Collectively, we provide evidence that miR-135b is involved in the impaired osteogenic differentiation of MSCs derived from MM patients and might therefore be a promising target for controlling bone disease.

Jiang D, Aguiar RC
MicroRNA-155 controls RB phosphorylation in normal and malignant B lymphocytes via the noncanonical TGF-β1/SMAD5 signaling module.
Blood. 2014; 123(1):86-93 [PubMed] Free Access to Full Article Related Publications
MicroRNA-155 (miR-155) plays pleiotropic roles in the biology of normal and malignant B lymphocytes, including the modulation of the transforming growth factor β (TGF-β) pathway via the targeting of SMAD5. However, the extent of the miR-155-mediated disruption of the TGF-β1/SMAD5 axis remains to be elucidated. To address this issue, we used the miR-155 knockout (KO) mouse and diffuse large B-cell lymphoma (DLBCL) cell lines ectopically expressing miR-155. In the DLBCL models, expression of miR-155 blocked TGF-β1-mediated activation of the retinoblastoma protein (RB), decreasing the abundance of the inhibitory pRB-E2F1 complex and limiting G0/G1 arrest. Genetic knockdown of SMAD5, p15, or p21 recapitulated these effects, establishing a circuitry whereby the targeting of SMAD5 by miR-155 blunts the TGF-β1-induced transcription of p15 and p21, thus sustaining RB phosphorylation and inactivity. Next, we demonstrated that SMAD5 levels are elevated in mature B lymphocytes from the miR-155 KO mice, which display a heightened sensitivity to TGF-β1 characterized by suppression of RB phosphorylation and more pronounced G0/G1 cell cycle arrest. Our findings suggest that a miR-155-mediated perturbation of the RB/E2F axis may play a role in DLBCL pathogenesis, and contribute to the reduced number of germinal center B cells and impaired T cell-dependent antibody response found in the miR-155 KO mice.

Huo L, Liu K, Pei J, et al.
Fluoride promotes viability and differentiation of osteoblast-like Saos-2 cells via BMP/Smads signaling pathway.
Biol Trace Elem Res. 2013; 155(1):142-9 [PubMed] Free Access to Full Article Related Publications
The BMP/Smad signaling pathway plays an important role in the viability and differentiation of osteoblast; however, it is not clear whether this pathway is involved in the fluoride-induced osteoblast differentiation. In this study, we investigated the role of BMP/Smad signaling pathway in fluoride-induced osteoblast-like Saos-2 cells differentiation. Cells were exposed to fluoride of different concentrations (0, 0.1, 0.2, 0.4, 0.8, and 1.6 mM), and cell proliferation was determined using WST assays. The expression of osteoblast marker genes such as osteocalcin (BGP) and bone alkaline phosphatase (BALP) were detected by qRT-PCR. We found that fluoride enhanced the proliferation of Saos-2 cells in a dose-dependent manner and 0.2 mM of fluoride resulted in a higher expression of osteoblast marker genes. In addition, immunofluorescence analysis showed that the promotion effects of 0.2 mM of fluoride on Saos-2 cells differentiation were associated with the activation of the BMP/Smad pathway. Expression of phosphorylated Smad1/5(p-Smad1/5) was higher in cells exposed to 0.2 mM of fluoride. Plasmid expression vectors encoding the short hairpin RNA (shRNA) targeting Smad4 gene were used to block the BMP/Smad pathway, which resulted in a significantly reduced expression of BGP and BALP as well as their corresponding mRNA. The mRNA levels after transfection remained low even in the presence of fluoride. The present results reveal that BMP/Smad signaling pathway was altered during the period of osteogenesis, and that the activities of p-Smad1/5 were required for Saos-2 cells viability and differentiation induced by fluoride.

Savary K, Caglayan D, Caja L, et al.
Snail depletes the tumorigenic potential of glioblastoma.
Oncogene. 2013; 32(47):5409-20 [PubMed] Free Access to Full Article Related Publications
Glioblastoma multiforme (GBM) is an aggressive brain malignancy characterized by high heterogeneity and invasiveness. It is increasingly accepted that the refractory feature of GBM to current therapies stems from the existence of few tumorigenic cells that sustain tumor growth and spreading, the so-called glioma-initiating cells (GICs). Previous studies showed that cytokines of the bone morphogenetic protein (BMP) family induce differentiation of the GICs, and thus act as tumor suppressors. Molecular pathways that explain this behavior of BMP cytokines remain largely elusive. Here, we show that BMP signaling induces Smad-dependent expression of the transcriptional regulator Snail in a rapid and sustained manner. Consistent with its already established promigratory function in other cell types, we report that Snail silencing decreases GBM cell migration. Consequently, overexpression of Snail increases GBM invasiveness in a mouse xenograft model. Surprisingly, we found that Snail depletes the GBM capacity to form gliomaspheres in vitro and to grow tumors in vivo, both of which are important features shared by GICs. Thus Snail, acting downstream of BMP signaling, dissociates the invasive capacity of GBM cells from their tumorigenic potential.

D'Assoro AB, Liu T, Quatraro C, et al.
The mitotic kinase Aurora--a promotes distant metastases by inducing epithelial-to-mesenchymal transition in ERα(+) breast cancer cells.
Oncogene. 2014; 33(5):599-610 [PubMed] Free Access to Full Article Related Publications
In this study, we demonstrate that constitutive activation of Raf-1 oncogenic signaling induces stabilization and accumulation of Aurora-A mitotic kinase that ultimately drives the transition from an epithelial to a highly invasive mesenchymal phenotype in estrogen receptor α-positive (ERα(+)) breast cancer cells. The transition from an epithelial- to a mesenchymal-like phenotype was characterized by reduced expression of ERα, HER-2/Neu overexpression and loss of CD24 surface receptor (CD24(-/low)). Importantly, expression of key epithelial-to-mesenchymal transition (EMT) markers and upregulation of the stemness gene SOX2 was linked to acquisition of stem cell-like properties such as the ability to form mammospheres in vitro and tumor self-renewal in vivo. Moreover, aberrant Aurora-A kinase activity induced phosphorylation and nuclear translocation of SMAD5, indicating a novel interplay between Aurora-A and SMAD5 signaling pathways in the development of EMT, stemness and ultimately tumor progression. Importantly, pharmacological and molecular inhibition of Aurora-A kinase activity restored a CD24(+) epithelial phenotype that was coupled to ERα expression, downregulation of HER-2/Neu, inhibition of EMT and impaired self-renewal ability, resulting in the suppression of distant metastases. Taken together, our findings show for the first time the causal role of Aurora-A kinase in the activation of EMT pathway responsible for the development of distant metastases in ERα(+) breast cancer cells. Moreover, this study has important translational implications because it highlights the mitotic kinase Aurora-A as a novel promising therapeutic target to selectively eliminate highly invasive cancer cells and improve the disease-free and overall survival of ERα(+) breast cancer patients resistant to conventional endocrine therapy.

Ding D, Lou X, Hua D, et al.
Recurrent targeted genes of hepatitis B virus in the liver cancer genomes identified by a next-generation sequencing-based approach.
PLoS Genet. 2012; 8(12):e1003065 [PubMed] Free Access to Full Article Related Publications
Integration of the viral DNA into host chromosomes was found in most of the hepatitis B virus (HBV)-related hepatocellular carcinomas (HCCs). Here we devised a massive anchored parallel sequencing (MAPS) method using next-generation sequencing to isolate and sequence HBV integrants. Applying MAPS to 40 pairs of HBV-related HCC tissues (cancer and adjacent tissues), we identified 296 HBV integration events corresponding to 286 unique integration sites (UISs) with precise HBV-Human DNA junctions. HBV integration favored chromosome 17 and preferentially integrated into human transcript units. HBV targeted genes were enriched in GO terms: cAMP metabolic processes, T cell differentiation and activation, TGF beta receptor pathway, ncRNA catabolic process, and dsRNA fragmentation and cellular response to dsRNA. The HBV targeted genes include 7 genes (PTPRJ, CNTN6, IL12B, MYOM1, FNDC3B, LRFN2, FN1) containing IPR003961 (Fibronectin, type III domain), 7 genes (NRG3, MASP2, NELL1, LRP1B, ADAM21, NRXN1, FN1) containing IPR013032 (EGF-like region, conserved site), and three genes (PDE7A, PDE4B, PDE11A) containing IPR002073 (3', 5'-cyclic-nucleotide phosphodiesterase). Enriched pathways include hsa04512 (ECM-receptor interaction), hsa04510 (Focal adhesion), and hsa04012 (ErbB signaling pathway). Fewer integration events were found in cancers compared to cancer-adjacent tissues, suggesting a clonal expansion model in HCC development. Finally, we identified 8 genes that were recurrent target genes by HBV integration including fibronectin 1 (FN1) and telomerase reverse transcriptase (TERT1), two known recurrent target genes, and additional novel target genes such as SMAD family member 5 (SMAD5), phosphatase and actin regulator 4 (PHACTR4), and RNA binding protein fox-1 homolog (C. elegans) 1 (RBFOX1). Integrating analysis with recently published whole-genome sequencing analysis, we identified 14 additional recurrent HBV target genes, greatly expanding the HBV recurrent target list. This global survey of HBV integration events, together with recently published whole-genome sequencing analyses, furthered our understanding of the HBV-related HCC.

Tong CW, Wang JL, Jiang MS, et al.
Novel genes that mediate nuclear respiratory factor 1-regualted neurite outgrowth in neuroblastoma IMR-32 cells.
Gene. 2013; 515(1):62-70 [PubMed] Related Publications
Nuclear respiratory factor-1 (NRF-1) is a transcription factor that functions in neurite outgrowth; however, the genes downstream from NRF-1 that mediate this function remain largely unknown. This study employs a genome-wide analysis approach to identify NRF-1-targeted genes in human neuroblastoma IMR-32 cells. A total of 916 human genes containing the putative NRF-1 response element (NRE) in their promoter regions were identified using a cutoff score determined by results from electrophoretic mobility shift assays (EMSA). Seventy-four NRF-1 target genes were listed according to the typical locations and high conservation of NREs. Fifteen genes, MAPRE3, NPDC1, RAB3IP, TRAPPC3, SMAD5, PIP5K1A, USP10, SPRY4, GTF2F2, NR1D1, SUV39H2, SKA3, RHOA, RAPGEF6, and SMAP1 were selected for biological confirmation. EMSA and chromatin immunoprecipitation confirmed that all NREs of these fifteen genes are critical for NRF-1 binding. Quantitative RT-PCR demonstrated that mRNA levels of 12 of these genes are regulated by NRF-1. Overexpression or knockdown of candidate genes demonstrated that MAPRE3, NPDC1, SMAD5, USP10, SPRY4, GTF2F2, SKA3, SMAP1 positively regulated, and RHOA and RAPGEF6 negatively regulated neurite outgrowth. Overall, our data showed that the combination of genome-wide bioinformatic analysis and biological experiments helps to identify the novel NRF-1-regulated genes, which play roles in differentiation of neuroblastoma cells.

Gupta A, Cao W, Chellaiah MA
Integrin αvβ3 and CD44 pathways in metastatic prostate cancer cells support osteoclastogenesis via a Runx2/Smad 5/receptor activator of NF-κB ligand signaling axis.
Mol Cancer. 2012; 11:66 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Bone loss and pathological fractures are common skeletal complications associated with androgen deprivation therapy and bone metastases in prostate cancer patients. We have previously demonstrated that prostate cancer cells secrete receptor activator of NF-kB ligand (RANKL), a protein essential for osteoclast differentiation and activation. However, the mechanism(s) by which RANKL is produced remains to be determined. The objective of this study is to gain insight into the molecular mechanisms controlling RANKL expression in metastatic prostate cancer cells.
RESULTS: We show here that phosphorylation of Smad 5 by integrin αvβ3 and RUNX2 by CD44 signaling, respectively, regulates RANKL expression in human-derived PC3 prostate cancer cells isolated from bone metastasis. We found that RUNX2 intranuclear targeting is mediated by phosphorylation of Smad 5. Indeed, Smad5 knock-down via RNA interference and inhibition of Smad 5 phosphorylation by an αv inhibitor reduced RUNX2 nuclear localization and RANKL expression. Similarly, knockdown of CD44 or RUNX2 attenuated the expression of RANKL. As a result, conditioned media from these cells failed to support osteoclast differentiation in vitro. Immunohistochemistry analysis of tissue microarray sections containing primary prostatic tumor (grade2-4) detected predominant localization of RUNX2 and phosphorylated Smad 5 in the nuclei. Immunoblotting analyses of nuclear lysates from prostate tumor tissue corroborate these observations.
CONCLUSIONS: Collectively, we show that CD44 signaling regulates phosphorylation of RUNX2. Localization of RUNX2 in the nucleus requires phosphorylation of Smad-5 by integrin αvβ3 signaling. Our results suggest possible integration of two different pathways in the expression of RANKL. These observations imply a novel mechanistic insight into the role of these proteins in bone loss associated with bone metastases in patients with prostate cancer.

Tripurani SK, Cook RW, Eldin KW, Pangas SA
BMP-specific SMADs function as novel repressors of PDGFA and modulate its expression in ovarian granulosa cells and tumors.
Oncogene. 2013; 32(33):3877-85 [PubMed] Free Access to Full Article Related Publications
Platelet-derived growth factor alpha (PDGFA) is frequently upregulated in various cancers and thought to function as a key player in the development and progression of tumor growth by regulating aspects of cell proliferation, angiogenesis and metastasis. However, the mechanism by which it is upregulated is not fully understood. Previously, we demonstrated that conditional deletion of two transcription factors that signal for the bone morphogenetic proteins (Smad1 and Smad5) in ovarian granulosa cells causes metastatic granulosa cell tumors (GCTs) in female mice and phenocopies human juvenile GCTs (JGCTs). Smad1/5 double conditional knockout tumors, as well as human JGCTs, are highly vascularized, hemorrhagic and mitotically active. Expression analysis of these tumors and their metastases revealed a significant upregulation of key proliferation and pro-angiogenic factors such as Pdgfa, Pdgfb and Vegf. We examined whether these genes were direct targets of SMAD1 and SMAD5. Knockdown of SMAD1 and SMAD5 in mouse primary granulosa cells and a human GCT-derived cell line (COV434) resulted in upregulation of PDGFA, but not PDGFB nor VEGF. We identified several putative SMAD1/5-binding sites in the PDGFA promoter, and chromatin immunoprecipitation and reporter assays demonstrated that SMAD1/5 interact with the PDGFA promoter to regulate its activity. Further, SMAD1/5 antagonize the activity of the transcription factor Sp1, a well-known positive regulator of PDGFA, by inhibiting its occupancy at a key regulatory site on the proximal PDGFA promoter. Collectively, our studies establish that loss of SMAD1/5 leads to upregulation of PDGFA in ovarian granulosa cells, and that a novel regulatory interaction exists between the BR-SMADs and Sp1 in controlling PDGFA expression during granulosa cell tumorigenesis.

Coradini D, Fornili M, Ambrogi F, et al.
TP53 mutation, epithelial-mesenchymal transition, and stemlike features in breast cancer subtypes.
J Biomed Biotechnol. 2012; 2012:254085 [PubMed] Free Access to Full Article Related Publications
Altered p53 protein is prevalently associated with the pathologic class of triple-negative breast cancers and loss of p53 function has recently been linked to the induction of an epithelial-mesenchymal transition (EMT) and acquisition of stemness properties. We explored the association between TP53 mutational status and expression of some genes involved in the canonical TGF-β signaling pathway (the most potent EMT inducer) and in two early EMT associated events: loss of cell polarity and acquisition of stemness-associated features. We used a publicly accessible microarray dataset consisting of 251 p53-sequenced primary breast cancers. Statistical analysis indicated that mutant p53 tumors (especially those harboring a severe mutation) were consistent with the aggressive class of triple-negative cancers and that, differently from cell cultures, surgical tumors underexpressed some TGF-β related transcription factors known as involved in EMT (ID1, ID4, SMAD3, SMAD4, SMAD5, ZEB1). These unexpected findings suggest an interesting relationship between p53 mutation, mammary cell dedifferentiation, and the concomitant acquisition of stemlike properties (as indicated by the overexpression of PROM1 and NOTCH1 genes), which improve tumor cells aggressiveness as indicated by the overexpression of genes associated with cell proliferation (CDK4, CDK6, MKI67) and migration (CXCR4, MMP1).

Grönroos E, Kingston IJ, Ramachandran A, et al.
Transforming growth factor β inhibits bone morphogenetic protein-induced transcription through novel phosphorylated Smad1/5-Smad3 complexes.
Mol Cell Biol. 2012; 32(14):2904-16 [PubMed] Free Access to Full Article Related Publications
In vivo cells receive simultaneous signals from multiple extracellular ligands and must integrate and interpret them to respond appropriately. Here we investigate the interplay between pathways downstream of two transforming growth factor β (TGF-β) superfamily members, bone morphogenetic protein (BMP) and TGF-β. We show that in multiple cell lines, TGF-β potently inhibits BMP-induced transcription at the level of both BMP-responsive reporter genes and endogenous BMP target genes. This inhibitory effect requires the TGF-β type I receptor ALK5 and is independent of new protein synthesis. Strikingly, we show that Smad3 is required for TGF-β's inhibitory effects, whereas Smad2 is not. We go on to demonstrate that TGF-β induces the formation of complexes comprising phosphorylated Smad1/5 and Smad3, which bind to BMP-responsive elements in vitro and in vivo and mediate TGF-β-induced transcriptional repression. Furthermore, loss of Smad3 confers on TGF-β the ability to induce transcription via BMP-responsive elements. Our results therefore suggest that not only is Smad3 important for mediating TGF-β's inhibitory effects on BMP signaling but it also plays a critical role in restricting the transcriptional output in response to TGF-β.

Wahdan-Alaswad RS, Bane KL, Song K, et al.
Inhibition of mTORC1 kinase activates Smads 1 and 5 but not Smad8 in human prostate cancer cells, mediating cytostatic response to rapamycin.
Mol Cancer Res. 2012; 10(6):821-33 [PubMed] Free Access to Full Article Related Publications
Although hyperactivated mTOR is well recognized as being pivotal to prostate cancer growth and progression, the underlying mechanisms by which it promotes such responses remain incompletely understood. Here, we show that rapamycin activates Smads 1 and 5 in human prostate cancer cells and tissues through blocking mTORC1 kinase. Small hairpin RNA-based gene silencing and gene overexpression approaches reveal that Smads 1 and 5 mediate, whereas Smad8 represses, rapamycin-induced cell death and expression of the bone morphogenetic protein (BMP) transcriptional target Id1 in human prostate cancer cell lines. Moreover, such phospho-Smad1/5-mediated rapamycin responses were blocked by LDN-193189 (a BMPRI kinase inhibitor) or Noggin (a BMP antagonist) in LNCaP prostate cancer cells. Likewise, the mTOR kinase inhibitors Ku-0063794 and WYE-354 each enhanced phosphorylation of Smad1/5. Intriguingly, silencing raptor alone enhanced, whereas silencing rictor repressed, the phosphorylation of Smad1/5, indicating that mTORC1 represses, whereas mTORC2 activates, BMP signaling. Immunohistochemical analysis showed increased levels of phospho-Smad1/5 concomitant with suppression of phospho-S6 and survivin levels in PC3 human prostate cancer xenografts in athymic mice administered rapamycin (intraperitoneally, 5 mg/kg/d, 2-6 days). Moreover, we show that compared with prostate tumor tissue from untreated patients, levels of phospho-Smad1/5 were significantly elevated in the prostate tumor tissue of patients with high-risk prostate cancer who received 8 weeks of the rapalog everolimus as part of a neoadjuvant clinical trial before undergoing local definitive therapy by radical prostatectomy. Taken together, our data implicate Smads 1, 5 and 8 as potential prognostic markers and therapeutic targets for mTOR inhibition therapy of prostate cancer.

Lichner Z, Mejia-Guerrero S, Ignacak M, et al.
Pleiotropic action of renal cell carcinoma-dysregulated miRNAs on hypoxia-related signaling pathways.
Am J Pathol. 2012; 180(4):1675-87 [PubMed] Related Publications
The von Hippel-Lindau (VHL) gene is lost in ≈ 70% of all renal cell carcinomas (RCCs); however, increasing evidence supports the involvement of alternative mechanisms in the regulation of VHL expression, including suppression by microRNAs (miRNAs). miRNAs are small, noncoding RNA molecules that regulate gene expression through binding to target mRNAs. In this study, we found that miRNAs, which are dysregulated in cases of RCC, can target multiple members of RCC-related signaling pathways. Importantly, both VHL and the hypoxia-inducible factor 1-α gene are experimentally validated and are likely direct targets of miR-17-5p and miR-224, as shown by both luciferase assay and Western blot analysis. We found a negative correlation between miR-17-5p and its two predicted targets, VEGF-A and EGLN3, and between miR-224 and its targets SMAD4 and SMAD5 in RCC specimens, suggesting that downstream signaling pathways are also modulated by clear cell RCC-dysregulated miRs. Results from our bioinformatics analysis show that a single miRNA molecule can target multiple components of the same pathway and that multiple miRNAs can target the same molecule. Our results also indicate that miRNAs represent a mechanism for the inactivation of VHL in cases of RCC and can elucidate a new dimension in cancer pathogenesis. As such, miRNAs exemplify new potential therapeutic targets with a significant effect on both tumor growth and metastatic potential.

Fellenberg J, Saehr H, Lehner B, Depeweg D
A microRNA signature differentiates between giant cell tumor derived neoplastic stromal cells and mesenchymal stem cells.
Cancer Lett. 2012; 321(2):162-8 [PubMed] Related Publications
Giant cell tumor (GCT) derived stromal cells (GCTSCs) have been identified as the neoplastic cell population of GCTs. Within these stromal cells a subpopulation has been identified that shares several features with mesenchymal stem cells (MSCs) indicating that these neoplastic cells develop from MSCs. Although spontaneous transformations of MSC have already been observed in vitro and in vivo the underlying molecular mechanisms are poorly understood. As microRNAs are crucially involved in tumorigenesis and the modulation of stem cell fate and behavior, they represent promising candidates for the regulation of this process. Therefore, the aim of this study was the comparative analysis of the microRNA expression profiles of GCTSCs and MSCs in order to identify differentially expressed microRNAs and their target genes. We could identify a microRNA signature consisting of 26 differentially expressed microRNAs that perfectly separates these two cell types. One of the microRNAs with the most pronounced differences in expression levels was miR-224. We could confirm the already known regulation of the apoptosis inhibitor API5 by miR-224 and could further identify three novel miR-224 target genes (SMAD5, SLMAP, H3.3B). The involvement of these genes in the regulation of apoptosis resistance, proliferation, differentiation and the regulation of gene transcription suggests pivotal roles of these genes in the neoplastic transformation of MSCs during GCT development.

Wu S, Lin Y, Xu D, et al.
MiR-135a functions as a selective killer of malignant glioma.
Oncogene. 2012; 31(34):3866-74 [PubMed] Related Publications
Glioma is the most common and fatal primary brain tumor. Thus far, therapeutic strategies to efficiently and specifically antagonize glioma are limited and poorly developed. Here we report that glia-enriched miR-135a, a microRNA that is dramatically downregulated in malignant glioma and correlated with the pathological grading, is capable of inducing mitochondria-dependent apoptosis of malignant glioma by regulating various genes including STAT6, SMAD5 and BMPR2, as well as affecting the signaling pathway downstream. Moreover, this lethal effect is selectively towards malignant glioma cells, but not neurons and glial cells, through a novel mechanism. Our findings suggest an important role of miR-135a in glioma etiology and provide a potential candidate for malignant glioma therapy.

Shola DT, Wang H, Wahdan-Alaswad R, Danielpour D
Hic-5 controls BMP4 responses in prostate cancer cells through interacting with Smads 1, 5 and 8.
Oncogene. 2012; 31(19):2480-90 [PubMed] Free Access to Full Article Related Publications
Hydrogen peroxide-inducible clone-5 (Hic-5, or androgen receptor-associated protein 55) is a transforming growth factor-β-inducible LIM protein whose deregulation is implicated in the progression of prostate cancer. Here, we report that Hic-5 binds to Smads 1, 5 and 8, and represses bone morphogenetic protein (BMP) signaling responses. Myc-Hic-5 but not Myc-paxillin was specifically immunoprecipitated with anti-FLAG IgG1 from lysates of HEK293 co-transfected with either Myc-Hic-5 or Myc-paxillin and FLAG-tagged Smads 1, 5 or 8. We showed that such interactions require the LIM3 domain of Hic-5 and the MH2 domain of those Smads. Anti-Hic-5 antibody specifically pulled down endogenous Smad1 in both the PC3 human prostate cell line and primary cultures of rat prostate fibroblasts, supporting that Hic-5 binds to Smad1 at the endogenous level. Bacterially expressed glutathione S-transferase (GST)-Smads 1, 5 or 8, but not GST alone, pulled down in vitro transcribed and translated Hic-5, implicating that Hic-5 binds directly to Smads 1, 5 and 8. Significantly, using Hic-5 small hairpin RNA silencing and overexpression systems, we show that Hic-5 (at both the endogenous and exogenous levels) represses the ability of BMP4 to induce expression of the inhibitor of differentiation-1 (Id1; a downstream target gene of BMP), activate the Id1 gene promoter and induce apoptosis in human and rat prostate epithelial cells. Moreover, silencing of Hic-5 in PC3 cells as well as in the WPMY-1 human prostate stroma cell line greatly enhances the levels of endogenous phospho-Smad1/5/8. Finally, we provide fluorescent microscopic imaging to support that Smad1 and Hic-5 mutually interact also at the level of their nuclear export mechanisms. Collectively, these results provide the first evidence for a physical and mutual functional interaction between Hic-5 and the BMP signaling pathway.

Scollen S, Luccarini C, Baynes C, et al.
TGF-β signaling pathway and breast cancer susceptibility.
Cancer Epidemiol Biomarkers Prev. 2011; 20(6):1112-9 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: TGF-β acts as a suppressor of primary tumor initiation but has been implicated as a promoter of the later malignant stages. Here associations with risk of invasive breast cancer are assessed for single-nucleotide polymorphisms (SNP) tagging 17 genes in the canonical TGF-β ALK5/SMADs 2&3 and ALK1/SMADs 1&5 signaling pathways: LTBP1, LTBP2, LTBP4, TGFB1, TGFB2, TGFB3, TGFBR1(ALK5), ALK1, TGFBR2, Endoglin, SMAD1, SMAD2, SMAD3, SMAD4, SMAD5, SMAD6, and SMAD7 [Approved Human Gene Nomenclature Committee gene names: ACVRL1 (for ALK1) and ENG (for Endoglin)].
METHODS: Three-hundred-fifty-four tag SNPs (minor allele frequency > 0.05) were selected for genotyping in a staged study design using 6,703 cases and 6,840 controls from the Studies of Epidemiology and Risk Factors in Cancer Heredity (SEARCH) study. Significant associations were meta-analyzed with data from the NCI Polish Breast Cancer Study (PBCS; 1,966 cases and 2,347 controls) and published data from the Breast Cancer Association Consortium (BCAC).
RESULTS: Associations of three SNPs, tagging TGFB1 (rs1982073), TGFBR1 (rs10512263), and TGFBR2 (rs4522809), were detected in SEARCH; however, associations became weaker in meta-analyses including data from PBCS and BCAC. Tumor subtype analyses indicated that the TGFB1 rs1982073 association may be confined to increased risk of developing progesterone receptor negative (PR(-)) tumors [1.18 (95% CI: 1.09-1.28), 4.1 × 10(-5) (P value for heterogeneity of ORs by PR status = 2.3 × 10(-4))]. There was no evidence for breast cancer risk associations with SNPs in the endothelial-specific pathway utilizing ALK1/SMADs 1&5 that promotes angiogenesis.
CONCLUSION: Common variation in the TGF-β ALK5/SMADs 2&3 signaling pathway, which initiates signaling at the cell surface to inhibit cell proliferation, might be related to risk of specific tumor subtypes.
IMPACT: The subtype specific associations require very large studies to be confirmed.

Bakkebø M, Huse K, Hilden VI, et al.
TGF-β-induced growth inhibition in B-cell lymphoma correlates with Smad1/5 signalling and constitutively active p38 MAPK.
BMC Immunol. 2010; 11:57 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Cytokines of the transforming growth factor β (TGF-β) superfamily exert effects on proliferation, apoptosis and differentiation in various cell types. Cancer cells frequently acquire resistance to the anti-proliferative signals of TGF-β, which can be due to mutations in proteins of the signalling cascade. We compared the TGF-β-related signalling properties in B-cell lymphoma cell lines that were sensitive or resistant to TGF-β-induced anti-proliferative effects.
RESULTS: TGF-β sensitive cell lines expressed higher cell surface levels of the activin receptor-like kinase 5 (Alk-5), a TGF-β receptor type 1. The expression levels of the other TGF-β and bone morphogenetic protein receptors were comparable in the different cell lines. TGF-β-induced phosphorylation of Smad2 was similar in TGF-β sensitive and resistant cell lines. In contrast, activation of Smad1/5 was restricted to cells that were sensitive to growth inhibition by TGF-β. Moreover, with activin A we detected limited anti-proliferative effects, strong phosphorylation of Smad2, but no Smad1/5 phosphorylation. Up-regulation of the TGF-β target genes Id1 and Pai-1 was identified in the TGF-β sensitive cell lines. Constitutive phosphorylation of MAPK p38 was restricted to the TGF-β sensitive cell lines. Inhibition of p38 MAPK led to reduced sensitivity to TGF-β.
CONCLUSIONS: We suggest that phosphorylation of Smad1/5 is important for the anti-proliferative effects of TGF-β in B-cell lymphoma. Alk-5 was highly expressed in the sensitive cell lines, and might be important for signalling through Smad1/5. Our results indicate a role for p38 MAPK in the regulation of TGF-β-induced anti-proliferative effects.

Su D, Peng X, Zhu S, et al.
Role of p38 MAPK pathway in BMP4-mediated Smad-dependent premature senescence in lung cancer cells.
Biochem J. 2011; 433(2):333-43 [PubMed] Related Publications
BMP4 (bone morphogenetic protein 4) is a multifunctional cytokine known to exert its biological effects through a variety of signalling pathways. The diverse function of BMP4 appears to be due to multiple pathways activated by BMP4 itself. Our previous studies have demonstrated that BMP4 is able to drive lung cancer cells into a process of premature senescence; however, the signalling pathways, as well their interplays and roles associated with this process, are not well understood. To address these questions, in the present study we investigated the signalling and molecular mechanisms underlying the BMP4-induced senescence, and our data demonstrated that p38 MAPK (mitogen-activated protein kinase) and Smad pathways were necessary for this process. Meanwhile, the ERK1/2 (extracellular-signal-regulated kinase 1/2) pathway, which is required for senescence, was not activated by BMP4 in the lung cancer cell line NCI-H460. We also showed that the BMP4-responsive R-Smads (receptor-regulated Smads), i.e. Smad1 and Smad5, were necessary for the up-regulation of p16(INK)⁴(a) and p21(WAF)¹(/cip)¹ and for the induction of premature senescence. Furthermore, we found that activation of the p38 MAPK pathway by BMP4 was essential for the full activation of transcription potential of Smad1/5. Overall, the results of the present study implicate a complex co-operation between p38 MAPK and Smad pathways in BMP4-mediated premature senescence.

Rai D, Kim SW, McKeller MR, et al.
Targeting of SMAD5 links microRNA-155 to the TGF-beta pathway and lymphomagenesis.
Proc Natl Acad Sci U S A. 2010; 107(7):3111-6 [PubMed] Free Access to Full Article Related Publications
The mechanisms by which microRNA dysfunction contributes to the pathogenesis of diffuse large B cell lymphoma (DLBCL) are not well established. The identification of the genes and pathways directly targeted by these small regulatory RNAs is a critical step to advance this field. Using unbiased genome-wide approaches in DLBCL, we discovered that the oncogenic microRNA-155 (miR-155) directly targets the bone morphogenetic protein (BMP)-responsive transcriptional factor SMAD5. Surprisingly, we found that in DLBCL a noncanonical signaling module linking TGF-beta1 signals to SMAD5 is also active. In agreement with these data, miR-155 overexpression rendered DLBCLs resistant to the growth-inhibitory effects of both TGF-beta1 and BMPs, via defective induction of p21 and impaired cell cycle arrest. In confirmatory experiments, RNAi-based SMAD5 knockdown recapitulated in vitro and in vivo the effects miR-155 overexpression. Furthermore, in primary DLBCLs, miR-155 overexpression inhibited SMAD5 expression and disrupted its activity, as defined by individual and global analyses of its transcriptional targets. Together, our data helped explain miR-155 function, highlighted a hitherto unappreciated role of SMAD5 in lymphoma biology, and defined a unique mechanism used by cancer cells to escape TGF-beta's growth-inhibitory effects.

Liu S, Tian Z, Yin F, et al.
Expression and functional roles of Smad1 and BMPR-IB in glioma development.
Cancer Invest. 2009; 27(7):734-40 [PubMed] Related Publications
Here we report the negative correlation of phosphorylation of Smad1 and BMPR-IB expression with the development of human glioma. Western blot analysis showed that expression of both phospho-Smad1/5/8 and BMPR-IB were decreased in malignant glioma tissues compared with normal brain tissues. Kaplan-Meier survival curves revealed that lower expression ratio of phospho-Smad1/5/8 to Smad1 expression significantly correlates with poor patient survival. Transient transfection of BMPR-IB activates Smad1 signaling and induces differentiation and apoptosis of U251 and U87 glioblastoma cells. The effects could be blocked by cotransfection of Smad6. These results might provide new molecular marker and target for glioma diagnosis and therapy.

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