Gene Summary

Gene:SMAD5; SMAD family member 5
Aliases: DWFC, JV5-1, MADH5
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:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:mothers against decapentaplegic homolog 5
Source:NCBIAccessed: 01 September, 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 01 September 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 01 September, 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: SMAD5 (cancer-related)

Li F, Xu Y, Liu RL
SAMD5 mRNA was overexpressed in prostate cancer and can predict biochemical recurrence after radical prostatectomy.
Int Urol Nephrol. 2019; 51(3):443-451 [PubMed] Related Publications
PURPOSE: To identify a novel biomarker that can predict biochemical recurrence (BCR) after radical prostatectomy.
METHODS: The gene expression profile of SAMD5 in prostate cancer was explored based on the oncomine database and The Cancer Genomic Atlas (TCGA). The follow-up information and clinical pathologic variables were extracted from the following cohort study: TCGA_prostate carcinoma. And then, survival analysis was conducted using the Kaplan-Meier plot and Cox's proportional hazard regression model. Furthermore, another independent cohort study: Taylor prostate, was also acquired to validate the predictive effect of SAMD5 on BCR. In addition, the expression profile of SAMD5 in other cancer types was investigated using TCGA dataset.
RESULTS: SAMD5 mRNA was shown to be up-regulated in multiple microarray datasets of prostate cancer with the strict statistic criteria: p < 0.01 and fold change ≥ 2. In TCGA_PCa cohort study, high expression of SAMD5 was a risk factor for patients on post-operative BCR (HR 2.181, 95%CI 1.199-3.966, p = 0.011) and this predictive ability was independent of Gleason score and pathologic T stage (HR 2.018, 95%CI 1.102-3.698, p = 0.023). In another validating cohort study, the statistic trend was similar, and the pooled analysis by combining the two cohort study further confirmed its prognostic effect.
CONCLUSION: SAMD5 mRNA was overexpressed in prostate cancer and had powerful prognostic ability on predicting post-operative BCR, independent of Gleason score and pathologic T stage. Its high expression was associated with poor prognosis after RP.

Cafri G, Yossef R, Pasetto A, et al.
Memory T cells targeting oncogenic mutations detected in peripheral blood of epithelial cancer patients.
Nat Commun. 2019; 10(1):449 [PubMed] Free Access to Full Article Related Publications
T cells targeting shared oncogenic mutations can induce durable tumor regression in epithelial cancer patients. Such T cells can be detected in tumor infiltrating lymphocytes, but whether such cells can be detected in the peripheral blood of patients with the common metastatic epithelial cancer patients is unknown. Using a highly sensitive in vitro stimulation and cell enrichment of peripheral memory T cells from six metastatic cancer patients, we identified and isolated CD4

Yang C, Shao T, Zhang H, et al.
MiR-425 expression profiling in acute myeloid leukemia might guide the treatment choice between allogeneic transplantation and chemotherapy.
J Transl Med. 2018; 16(1):267 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Acute myeloid leukemia (AML) is a highly heterogeneous disease. MicroRNAs function as important biomarkers in the clinical prognosis of AML.
METHODS: This study identified miR-425 as a prognostic factor in AML by screening the TCGA dataset. A total of 162 patients with AML were enrolled for the study and divided into chemotherapy and allogeneic hematopoietic stem cell transplantation (allo-HSCT) groups.
RESULTS: In the chemotherapy group, patients with high miR-425 expression had significantly longer overall survival (OS) and event-free survival (EFS) compared with patients with low miR-425 expression. In multivariate analyses, high miR-425 expression remained independently predictive of a better OS (HR = 0.502, P = 0.005) and EFS (HR = 0.432, P = 0.001) compared with patients with low miR-425 expression. Then, all patients were divided into two groups based on the median expression levels of miR-425. Notably, the patients undergoing allo-HSCT had significantly better OS (HR = 0.302, P < 0.0001) and EFS (HR = 0.379, P < 0.0001) compared with patients treated with chemotherapy in the low-miR-425-expression group. Mechanistically, high miR-425 expression levels were associated with a profile significantly involved in regulating cellular metabolism. Among these genes, MAP3K5, SMAD2, and SMAD5 were predicted targets of miR-425.
CONCLUSIONS: The expression of miR-425 may be useful in identifying patients in need of strategies to select the optimal therapy between chemotherapy and allo-HSCT treatment regimens. Patients with low miR-425 expression may consider early allo-HSCT.

Zhang Q, Gan H, Song W, et al.
MicroRNA-145 promotes esophageal cancer cells proliferation and metastasis by targeting SMAD5.
Scand J Gastroenterol. 2018 Jun - Jul; 53(7):769-776 [PubMed] Related Publications
OBJECTIVE: To clarify the relative expression and molecular function of microRNA (miR)-145 in esophageal cancer and understand its mechanistic involvement in this disease.
MATERIAL AND METHODS: The relative expression of miR-145 in clinical samples was analyzed using the public GSE43732 dataset. The prognostic analysis with respect to miR-145 expression was performed with Kaplan-Meier plot. Cell viability was measured by MTT assay and the anchorage-independent growth was evaluated by soft agar assay. The migration and invasion of esophageal cancer cells were measured using transwell chamber. The regulatory effect of miR-145 on SMAD5 was determined by dual-luciferase reporter assay. The endogenous SMAD5 protein was measured by Western blot.
RESULTS: We demonstrated high expression of miR-145 associated with late stage and unfavorable prognosis of esophageal cancer. Ectopic expression of miR-145 mimic significantly stimulated cell proliferation and anchorage-independent growth. Furthermore, high level of miR-145 significantly promoted both migration and invasion in vitro. Notably, we identified SMAD5 as direct target of miR-145, the suppressed expression of which consequently led to increased cell proliferation and migration/invasion.
CONCLUSION: Our study uncovered the crucial role of miR-145/SMAD5 in esophageal cancer and highlighted its target potential for diagnostic and therapeutic purpose.

Wang M, Sun J, Xu B, et al.
Functional Characterization of MicroRNA-27a-3p Expression in Human Polycystic Ovary Syndrome.
Endocrinology. 2018; 159(1):297-309 [PubMed] Related Publications
The goal of this study was to characterize the function of microRNA-27a-3p (miR-27a-3p) in polycystic ovary syndrome (PCOS). miR-27a-3p expression was analyzed in excised granulosa cells (GCs) from 21 patients with PCOS and 12 normal patients undergoing in vitro fertilization cycle treatments and in 17 nontreated cuneiform ovarian resection PCOS samples and 13 control ovarian samples from patients without PCOS. We found that the expression of miR-27a-3p was significantly increased in both excised GCs and the ovaries of patients with PCOS compared with the controls. Insulin treatment of the human granulosa-like tumor cell line (KGN) resulted in decreased downregulated expression of miR-27a-3p, and this effect appeared to be mediated by signal transducer and activator of transcription STAT1 and STAT3. The overexpression of miR-27a-3p in KGN cells inhibited SMAD5, which in turn decreased cell proliferation and promoted cell apoptosis. After KGN cells were stimulated with insulin for 48 hours, there was increased expression of SMAD5 protein and decreased apoptosis. Additionally, knockdown/overexpression of SMAD5 in KGN cells reduced/increased cell number and promoted/inhibited cell apoptosis. Insulin-stimulated primary GCs isolated from patients with PCOS, in contrast to normal GCs or KGN cells, did not exhibit decreased miR-27a-3p expression. The differences in the expression levels in KGN cells and human PCOS GCs are likely explained by increased miR-27a-3p expression in the GCs caused by insulin resistance in PCOS. Taken together, our data provided evidence for a functional role of miR-27a-3p in the GCs' dysfunction that occurs in patients with PCOS.

Souza TM, van den Beucken T, Kleinjans JCS, Jennen DGJ
Inferring transcription factor activity from microarray data reveals novel targets for toxicological investigations.
Toxicology. 2017; 389:101-107 [PubMed] Related Publications
Transcription factors (TFs) are important modulators of the inducible portion of the transcriptome, and therefore relevant in the context of exposure to exogenous compounds. Current approaches to predict the activity of TFs in biological systems are usually restricted to a few entities at a time due to low-throughput techniques targeting a limited fraction of annotated human TFs. Therefore, high-throughput alternatives may help to identify new targets of mechanistic and predictive value in toxicological investigations. In this study, we inferred the activity multiple TFs using publicly available microarray data from primary human hepatocytes exposed to hundreds of chemicals and evaluated these molecular profiles using multiple correspondence analysis. Our results demonstrate that the lowest dose and latest exposure time (24h) in a subset of chemicals generates a signature indicative of carcinogenicity possibly due to DNA-damaging properties. Furthermore, profiles from the earliest exposure time (2h) and highest dose creates clusters of chemicals implicated in the development of diverse forms of drug-induced liver injury (DILI). Both approaches yielded a number of TFs with similar activity across groups of chemicals, including TFs known in toxicological responses such as AhR, NFE2L2 (Nrf2), NF-κB and PPARG. FOXM1, IRF1 and E2F4 were some of the TFs identified that may be relevant in genotoxic carcinogenesis. SMADs (SMAD1, SMAD2, SMAD5) and KLF5 were identified as some of potentially new TFs whose inferred activities were linked to acute and progressive outcomes in DILI. In conclusion this study offers a novel mechanistic approach targeting TF activity during chemical exposure.

Chiba T, Ishisaki A, Kyakumoto S, et al.
Transforming growth factor-β1 suppresses bone morphogenetic protein-2-induced mesenchymal-epithelial transition in HSC-4 human oral squamous cell carcinoma cells via Smad1/5/9 pathway suppression.
Oncol Rep. 2017; 37(2):713-720 [PubMed] Free Access to Full Article Related Publications
Squamous cell carcinoma is the most common cancer in the oral cavity. We previously demonstrated that transforming growth factor-β1 (TGF-β1) promotes the epithelial-mesenchymal transition (EMT) of human oral squamous cell carcinoma (hOSCC) cells; however, it remains to be clarified whether the TGF-β superfamily member bone morphogenetic protein (BMP) affects this process in hOSCC cells. Here, we examined the independent and collective effects of TGF-β1 and BMP-2 on EMT and mesenchymal‑epithelial transition (MET) in a panel of four hOSCC cell lines. Notably, we found that HSC-4 cells were the most responsive to BMP-2 stimulation, which resulted in the upregulation of Smad1/5/9 target genes such as the MET inducers ID1 and cytokeratin 9 (CK9). Furthermore, BMP-2 downregulated the mesenchymal marker N-cadherin and the EMT inducer Snail, but upregulated epithelial CK9 expression, indicating that BMP-2 prefers to induce MET rather than EMT. Moreover, TGF-β1 dampened BMP-2-induced epithelial gene expression by inhibiting Smad1/5/9 expression and phosphorylation. Functional analysis revealed that TGF-β1 and BMP-2 significantly enhanced HSC-4 cell migration and proliferation, respectively. Collectively, these data suggest that TGF-β positively regulates hOSCC invasion in the primary tumor, whereas BMP-2 facilitates cancer cell colonization at secondary metastatic sites. Thus, the invasive and metastatic characteristics of hOSCC appear to be reciprocally regulated by BMP and TGF-β.

Du C, Pan P, Jiang Y, et al.
Microarray data analysis to identify crucial genes regulated by CEBPB in human SNB19 glioma cells.
World J Surg Oncol. 2016; 14(1):258 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Glioma is one of the most common primary malignancies in the brain or spine. The transcription factor (TF) CCAAT/enhancer binding protein beta (CEBPB) is important for maintaining the tumor initiating capacity and invasion ability. To investigate the regulation mechanism of CEBPB in glioma, microarray data GSE47352 was analyzed.
METHODS: GSE47352 was downloaded from Gene Expression Omnibus, including three samples of SNB19 human glioma cells transduced with non-target control small hairpin RNA (shRNA) lentiviral vectors for 72 h (normal glioma cells) and three samples of SNB19 human glioma cells transduced with CEBPB shRNA lentiviral vectors for 72 h (CEBPB-silenced glioma cells). The differentially expressed genes (DEGs) were screened using limma package and then annotated. Afterwards, the Database for Annotation, Visualization, and Integrated Discovery (DAVID) software was applied to perform enrichment analysis for the DEGs. Furthermore, the protein-protein interaction (PPI) network and transcriptional regulatory network were constructed using Cytoscape software.
RESULTS: Total 529 DEGs were identified in the normal glioma cells compared with the CEBPB-silenced glioma cells, including 336 up-regulated and 193 down-regulated genes. The significantly enriched pathways included chemokine signaling pathway (which involved CCL2), focal adhesion (which involved THBS1 and THBS2), TGF-beta signaling pathway (which involved THBS1, THBS2, SMAD5, and SMAD6) and chronic myeloid leukemia (which involved TGFBR2 and CCND1). In the PPI network, CCND1 (degree = 29) and CCL2 (degree = 12) were hub nodes. Additionally, CEBPB and TCF12 might function in glioma through targeting others (CEBPB → TCF12, CEBPB → TGFBR2, and TCF12 → TGFBR2).
CONCLUSIONS: CEBPB might act in glioma by regulating CCL2, CCND1, THBS1, THBS2, SMAD5, SMAD6, TGFBR2, and TCF12.

Sayagués JM, Corchete LA, Gutiérrez ML, et al.
Genomic characterization of liver metastases from colorectal cancer patients.
Oncotarget. 2016; 7(45):72908-72922 [PubMed] Free Access to Full Article Related Publications
Metastatic dissemination is the most frequent cause of death of sporadic colorectal cancer (sCRC) patients. Genomic abnormalities which are potentially characteristic of such advanced stages of the disease are complex and so far, they have been poorly described and only partially understood. We evaluated the molecular heterogeneity of sCRC tumors based on simultaneous assessment of the overall GEP of both coding mRNA and non-coding RNA genes in primary sCRC tumor samples from 23 consecutive patients and their paired liver metastases. Liver metastases from the sCRC patients analyzed, systematically showed deregulated transcripts of those genes identified as also deregulated in their paired primary colorectal carcinomas. However, some transcripts were found to be specifically deregulated in liver metastases (vs. non-tumoral colorectal tissues) while expressed at normal levels in their primary tumors, reflecting either an increased genomic instability of metastatic cells or theiradaption to the liver microenvironment. Newly deregulated metastatic transcripts included overexpression of APOA1, HRG, UGT2B4, RBP4 and ADH4 mRNAS and the miR-3180-3p, miR-3197, miR-3178, miR-4793 and miR-4440 miRNAs, together with decreased expression of the IGKV1-39, IGKC, IGKV1-27, FABP4 and MYLK mRNAS and the miR-363, miR-1, miR-143, miR-27b and miR-28-5p miRNAs. Canonical pathways found to be specifically deregulated in liver metastatic samples included multiple genes related with intercellular adhesion and the metastatic processes (e.g., IGF1R, PIK3CA, PTEN and EGFR), endocytosis (e.g., the PDGFRA, SMAD2, ERBB3, PML and FGFR2), and the cell cycle (e.g., SMAD2, CCND2, E2F5 and MYC). Our results also highlighted the activation of genes associated with the TGFβ signaling pathway, -e.g. RHOA, SMAD2, SMAD4, SMAD5, SMAD6, BMPR1A, SMAD7 and MYC-, which thereby emerge as candidate genes to play an important role in CRC tumor metastasis.

Gregoire JM, Fleury L, Salazar-Cardozo C, et al.
Identification of epigenetic factors regulating the mesenchyme to epithelium transition by RNA interference screening in breast cancer cells.
BMC Cancer. 2016; 16:700 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: In breast cancer, the epithelial to mesenchyme transition (EMT) is associated to tumour dissemination, drug resistance and high relapse risks. It is partly controlled by epigenetic modifications such as histone acetylation and methylation. The identification of genes involved in these reversible modifications represents an interesting therapeutic strategy to fight metastatic disease by inducing mesenchymal cell differentiation to an epithelial phenotype.
METHODS: We designed a siRNA library based on chromatin modification-related to functional domains and screened it in the mesenchymal breast cancer cell line MDA-MB-231. The mesenchyme to epithelium transition (MET) activation was studied by following human E-CADHERIN (E-CAD) induction, a specific MET marker, and cell morphology. Candidate genes were validated by studying the expression of several differential marker genes and their impact on cell migration.
RESULTS: The screen led to the identification of 70 gene candidates among which some are described to be, directly or indirectly, involved in EMT like ZEB1, G9a, SMAD5 and SMARCD3. We also identified the DOT1L as involved in EMT regulation in MDA-MB-231. Moreover, for the first time, KAT5 gene was linked to the maintenance of the mesenchymal phenotype.
CONCLUSIONS: A multi-parametric RNAi screening approach was developed to identify new EMT regulators such as KAT5 in the triple negative breast cancer cell line MDA-MB-231.

Attar-Schneider O, Drucker L, Gottfried M
Migration and epithelial-to-mesenchymal transition of lung cancer can be targeted via translation initiation factors eIF4E and eIF4GI.
Lab Invest. 2016; 96(9):1004-15 [PubMed] Related Publications
Metastasis underlies cancer morbidity and accounts for disease progression and significant death rates generally and in non-small cell lung cancer (NSCLC) particularly. Therefore, it is critically important to understand the molecular events that regulate metastasis. Accumulating data portray a central role for protein synthesis, particularly translation initiation (TI) factors eIF4E and eIF4G in tumorigenesis and patients' survival. We have published that eIF4E/eIF4GI activities and consequently NSCLC cell migration are modulated by bone-marrow mesenchymal stem cell secretomes, suggesting a role for TI in metastasis. Here, we aimed to expand our understanding of the TI factors significance to NSCLC characteristics, particularly epithelial-to-mesenchymal transition (EMT) and migration, supportive of metastasis. In a model of NSCLC cell lines (H1299, H460), we inhibited eIF4E/eIF4GI's expressions (siRNA, ribavirin) and assessed NSCLC cell lines' migration (scratch), differentiation (EMT, immunoblotting), and expression of select microRNAs (qPCR). Initially, we determined an overexpression of several TI factors (eIF4E, eIF4GI, eIF4B, and DHX29) and their respective targets in NSCLC compared with normal lung samples (70-350%↑, P<0.05). Knockdown (KD) of eIF4E/eIF4GI in NSCLC cell lines (70%↓, P<0.05) also manifested in decreased target levels (ERα, SMAD5, NFkB, CyclinD1, c-MYC, and HIF1α) (20-50%↓, P<0.05). eIF4E/eIF4GI KD also attenuated cell migration (60-75%↓, P<0.05), EMT promoters (15-90%↓, P<0.05), and enhanced EMT suppressors (30-380%↑, P<0.05). The importance of eIF4E KD to NSCLC phenotype was further corroborated with its inhibitor, ribavirin. Changes in expression of essential microRNAs implicated in NSCLC cell migration concluded the study (20-100%, P<0.05). In summary, targeting eIF4E/eIF4GI reduces migration and EMT, both essential for metastasis, thereby underscoring the potential of TI targeting in NSCLC therapy, especially the already clinically employed agents (ribavirin/4EGI). Comparison of these findings with previously reported effects of eIF4E/eIF4GI KD in multiple myeloma suggests a collective role for these TI factors in cancer progression.

Ke J, Lou J, Chen X, et al.
Identification of a functional variant for colorectal cancer risk mapping to chromosome 5q31.1.
Oncotarget. 2016; 7(23):35199-207 [PubMed] Free Access to Full Article Related Publications
Genome-wide association studies (GWASs) have established chromosome 5q31.1 as a risk locus for colorectal cancer (CRC). We previously identified a potentially regulatory single nucleotide polymorphism (SNP) rs17716310 within 5q31.1. Now, we extended our study with another independent Chinese population, functional assays and analyses of TCGA (The Cancer Genome Atlas) data. Significant associations between rs17716310 and CRC risk were found in Present Study including 1075 CRC cases and 1999 controls (additive model: OR = 1.149, 95% CI = 1.027-1.286, P = 0.016), and in Combined Study including 1766 cases and 2708 controls (additive model: OR = 1.145, 95% CI = 1.045-1.254, P = 0.004). Dual luciferase reporter gene assays indicated that the variant C allele obviously increased transcriptional activity. Using TCGA datasets, we indicated rs17716310 as a cis expression quantitative trait locus (eQTL) for the gene SMAD5, whose expression was significantly higher in CRC tissues. These findings suggested that the functional polymorphism rs17716310 A > C might be a genetic modifier for CRC, promoting the expression of SMAD5 that belonged to the transforming growth factor beta (TGF-β) signaling pathway.

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.

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