Overexpression Of sFRP1 Research Articles

Tumour necrosis factor α regulates the miR-27a-3p-Sfrp1 axis in a mouse model of osteoporosis.

Osteoporosis is a metabolic bone disease that involves gradual loss of bone density and mass, thus resulting in increased fragility and risk of fracture. Inflammatory cytokines, such as tumour necrosis factor α (TNF-α), inhibit osteogenic differentiation of bone marrow mesenchymal stem cells (BMSCs), and several microRNAs are implicated in osteoporosis development. This study aimed to explore the correlation between TNF-α treatment and miR-27a-3p expression in BMSC osteogenesis and further understand their roles in osteoporosis. An osteoporosis animal model was established using ovariectomized (OVX) mice. Compared with Sham mice, the OVX mice had a significantly elevated level of serum TNF-α and decreased level of bone miR-27a-3p, and in vitro TNF-α treatment inhibited miR-27a-3p expression in BMSCs. In addition, miR-27a-3p promoted osteogenic differentiation of mouse BMSCs in vitro, as evidenced by alkaline phosphatase staining and Alizarin Red-S staining, as well as enhanced expression of the osteogenic markers Runx2 and Osterix. Subsequent bioinformatics analysis combined with experimental validation identified secreted frizzled-related protein 1 (Sfrp1) as a downstream target of miR-27a-3p. Sfrp1 overexpression significantly inhibited the osteogenic differentiation of BMSCs in vitro and additional TNF-α treatment augmented this inhibition. Moreover, Sfrp1 overexpression abrogated the promotive effect of miR-27a-3p on the osteogenic differentiation of BMSCs. Furthermore, the miR-27a-3p-Sfrp1 axis was found to exert its regulatory function in BMSC osteogenic differentiation via regulating Wnt3a-β-catenin signalling. In summary, this study revealed that TNF-α regulated a novel miR-27a-3p-Sfrp1 axis in osteogenic differentiation of BMSCs. The data provide new insights into the development of novel therapeutic strategies for osteoporosis.

H3K27me3 Inactivates SFRP1 to Promote Cell Proliferation via Wnt/β-Catenin Signaling Pathway in Esophageal Squamous Cell Carcinoma.

Histone methylations are generally considered to play an important role in multiple cancers by regulating cancer-related genes. This study aims to investigate the effects of H3K27me3-mediated inactivation of tumor suppressor gene SFRP1 and its function in esophageal squamous cell carcinoma (ESCC). We performed ChIP-seq on H3K27me3-enriched genomic DNA fragments in ESCC cells to screen out tumor suppressor genes that may be regulated by H3K27me3. ChIP-qPCR and Western blot were employed to explore the regulating mechanisms between H3K27me3 and SFRP1. Expression level of SFRP1 was assessed by quantitative real-time polymerase chain reaction (q-PCR) in 29 pairs of ESCC surgical samples. SFRP1 function in ESCC cells were detected by cell proliferation assay, colony formation assay and wound-healing assay. Our results indicated that H3K27me3 was widely distributed in the genome of ESCC cells. Specifically, we found that H3K27me3 deposited on the upstream region of SFRP1 promoter and inactivated SFRP1 expression. Furthermore, we found SFRP1 was significantly down-regulated in ESCC tissues compared with the adjacent non-tumor tissues, and SFRP1 expression was significantly associated with TNM stage and lymph node metastasis. In vitro cell-based assay indicated that over-expression of SFRP1 significantly suppressed cell proliferation and negatively correlated with the expression of β-catenin in the nucleus. Our study revealed a previously unrecognized finding that H3K27me3-mediated SFRP1 inhibit the cell proliferation of ESCC through inactivation of Wnt/β-catenin signaling pathway.

Identification of tumorigenic risk genes in human placenta-derived mesenchymal stem cells treated with 3-methylcholanthrene

Mesenchymal stem cells (MSCs) capable of tumour topotaxis have been served as cellular vehicles to deliver anti-tumour agents. As cellular components of the tumour microenvironment, MSCs also affect tumour progression. However, the tumour transformation-related genes of MSCs remain unclear since either tumorigenic or tumour suppressor effects within these cells have been researched. Hence, we aimed to identify potential biomarkers indicative of tumorigenic risk by RNA-seq analysis of human placenta tissue-derived MSCs (hPTMSCs) exposed to the carcinogenic agent, 3-methylcholanthrene (3-MC). Twenty-nine tumour transformation-related genes and three pluripotency-related genes were appraised as differentially expressed genes (DEGs) in hPTMSCs. Overexpression of sfrp1 led to reduced cell viability, migration, and colony formation in A549. In contrast, the overexpression of ptgs2 exerted the opposite effect. These results indicate that A549 cells with high ptgs2 expression but low sfrp1 expression may have a more potential tumorigenic capacity. Taken together, this study suggests that ptgs2 and sfrp1 may be tumorigenic risk genes.

Lcz696 Alleviates Myocardial Fibrosis After Myocardial Infarction Through the sFRP-1/Wnt/β-Catenin Signaling Pathway.

Background: Lcz696 (ARNI, angiotensin receptor–neprilysin inhibitor; sacubitril/valsartan) shows an inhibitory effect on fibrosis after myocardial infarction (MI). However, the underlying signaling mechanisms are poorly understood. The Wnt/β-catenin signaling pathway is activated after MI and participates in the process of myocardial fibrosis. Here, we aimed to assess the efficacy of ARNI for alleviating myocardial fibrosis after MI and hypothesized that ARNI alleviates myocardial fibrosis by inhibiting the Wnt/β-catenin signaling pathway and overexpressing sFRP-1, an inhibitor of the Wnt/β-catenin signaling pathway.Methods: Mice randomized at 1 week post-MI were administered lcz696 (60 mg/kg, n = 21), valsartan (30 mg/kg, n = 19), or corn oil (n = 13) orally for 4 weeks, while the sham-operated group received vehicle (corn oil, n = 19). Cardiac function and extent of myocardial fibrosis were measured. Western blotting and quantitative real-time polymerase chain reaction were used to detect the expression of Wnt/β-catenin pathway-related proteins. Furthermore, primary myocardial fibroblasts were stimulated with angiotensin II (Ang II) and cultured with lcz696 and the sFRP-1 inhibitor way316606 to detect the expression of Wnt/β-catenin pathway proteins.Results: Both lcz696 and valsartan alleviated myocardial fibrosis and improved cardiac function, but lcz696 had superior efficiency compared to valsartan. Furthermore, β-catenin expression was inhibited and sFRP-1 was overexpressed after drug treatment, which could be significantly improved by lcz696 in mice. In addition, lcz696 inhibited β-catenin expression in AngII-stimulated myocardial fibroblasts, and β-catenin expression increased after the inhibition of sFRP-1.Conclusion: ARNI alleviated cardiac fibrosis and cardiac remodeling by inhibiting the Wnt/β-catenin signaling pathway. In addition, ARNI can lead to overexpression of sFRP-1, which is an inhibitor of the Wnt/β-catenin signaling pathway. These results indicate a new therapeutic target of ARNI to improve myocardial fibrosis and prevent myocardial remodeling.

Sfrp1 protects against acute myocardial ischemia (AMI) injury in aged mice by inhibiting the Wnt/\u03b2-catenin signaling pathway

BackgroundAged patients suffering from acute myocardial ischemia (AMI) exhibit an increased mortality rate and worse prognosis, and a more effective treatment is currently in need. In the present study, we investigated potent targets related to Wnt/β-catenin pathway deregulation for AMI injury treatment.MethodsIn the present study, AAV-Sfrp1 was transduced into the myocardium of aged mice, and an AMI model was established in these aged mice to study the effect and molecular mechanism of Sfrp1 overexpression on AMI-induced injury.ResultsThe results showed that Sfrp1 was successfully overexpressed in the myocardium of aged mice and remarkably reduced Wnt/β-catenin pathway activity in aged mice after AMI, effectively reducing the degree of myocardial fibrosis, inhibiting cardiomyocyte apoptosis, and improving cardiac function. We revealed that the exogenous introduction of Sfrp1 could be considered a promising strategy for improving post-AMI injury in aged mice by inhibiting Wnt/β-catenin pathway activity.ConclusionsIn conclusion, the Wnt/β-catenin pathway potentially represents a key target in AMI in aged mice. Sfrp1 might be used as a small molecule gene therapy drug to improve heart function, reduce the degree of myocardial fibrosis, inhibit cardiomyocyte apoptosis and reduce AMI injury in aged mice by inhibiting the Wnt/β-catenin pathway, thereby effectively protecting aged hearts from AMI injury.

SFRP1 protects H9c2 cardiac myoblasts from doxorubicin-induced apoptosis by inhibiting the Wnt/PCP-JNK pathway.

Doxorubicin (Dox) is an effective chemotherapy drug against a wide range of cancers, including both hematological and solid tumors. However, the serious cardiotoxic effect restricted its clinical application. We previously have illuminated the protective role of canonical Wnt/β-catenin signaling in Dox-induced cardiotoxicity. Secreted frizzled-related protein 1 (sFRP1) is one of the endogenous inhibitors of both canonical and noncanonical Wnt signaling. In this study, we investigated the relationship between sFRP1 and noncanonical Wnt/PCP-JNK (Wnt/planar cell polarity-c-Jun N-terminal kinase) pathway in Dox-induced cardiotoxicity in vitro and in vivo. We showed that treatment of H9c2 cardiac myoblasts with Dox (1 μM) time-dependently suppressed cell viability accompanied by significantly decreased sFRP1 protein level and increased Wnt/PCP-JNK signaling. Pretreatment with SP600125, the Wnt/PCP-JNK signaling inhibitor, attenuated Dox-induced apoptosis of H9c2 cells. Overexpression of sFRP1 protected H9c2 cells from Dox-induced apoptosis by inhibiting the Wnt/PCP-JNK pathway. After intraperitoneal injection of a cumulative dose of 15 mg/kg Dox, rats displayed significant cardiac dysfunction; their heart showed inhibited Wnt/β-catenin signaling and activated Wnt/PCP-JNK signaling. These results suggest that sFRP1 may be a novel target for Dox-induced cardiotoxicity.

SFRP1 inhibited the epithelial ovarian cancer through inhibiting Wnt/β-catenin signaling.

Epithelial ovarian cancer is the most malignant gynecologic neoplasm accounting for 90% of the ovarian cancer patients. Researchers proved that epigenetic alterations could disrupt gene expression as often as genetic alterations. Secreted frizzed related protein (SFRP1), a Wnt antagonist, exerts a significant effect on ovarian cancer. The aim of this research was to investigate the effects and the mechanism of action of SFRP1 on epithelial ovarian cancer. Clinical specimens (including fallopian tubes epithelium from 60 epithelial ovarian cancer patients' and 20 healthy subjects who were undergoing surgical treatments), transgenic mice (overexpressing SFRP1 gene), and 4 epithelial ovarian cancer cell lines (including OVCAR4, SKOV3, COV644, TOV21G) were used in this study. Overexpression of SFRP1 in cells was carried out on OVCAR4 cells by transfection using Lipofectamine 2000. Gene transcription was analyzed by qRT-PCR. The methylation of SFRP1 gene was quantified by methylation-specific PCR. The level of protein expression was measured by Western blot or immunohistochemistry analysis. Cell proliferation was analyzed by CCK8 methods. The ability of cell migration and invasion were measured by wound healing assay and transwell assay. Abnormal expression level and hypermethylation status of SFRP1 were found in clinical epithelial ovarian cancer samples and cell lines. We observed that SFRP1 knockdown could promote proliferation, migration and invasion abilities of epithelial ovarian cancer cells. Additionally, we discovered a potential inhibitory effect of SFRP1 on Wnt/β-catenin signaling pathway in epithelial ovarian cancer cells. Furthermore, the anti-tumor effect of SFRP1 was tested in SFRP1 transgenic mice. SFRP1 inhibited epithelial ovarian cancer through inhibiting Wnt/β-catenin pathway, suggesting that SFRP1 could be considered as a potential therapeutic target in epithelial ovarian cancer.

RETRACTED: Silencing of Long Non-coding RNA HOTTIP Reduces Inflammation in Rheumatoid Arthritis by Demethylation of SFRP1

Accumulating evidence suggests long non-coding RNAs (lncRNAs) play crucial roles in the pathogenesis of rheumatoid arthritis (RA). Here, we aimed to define the role of HOXA transcript at the distal tip (HOTTIP) in RA pathogenesis in relation to SFRP1 methylation and Wnt signaling pathway. HOTTIP was found highly expressed, and SFRP1 was hypermethylated in RA synovial fibroblasts (RASFs). Next, gain- or loss-of-function experiments were conducted in RASFs to explore the effects of HOTTIP on the biological behaviors of RASFs. Silencing of HOTTIP or overexpression of SFRP1 inhibited RASF proliferation, invasion, and migration, while enhancing apoptosis. The relationship among HOTTIP, SFRP1, and Dnmt3b was determined using methylation-specific PCR (MSP), bisulfite sequencing PCR (BSP), RNA pull-down, RNA immunoprecipitation (RIP), and chromatin immunoprecipitation (ChIP) assays. The regulatory mechanisms of HOTTIP/Dnmt3b/SFRP1 were explored by altering their expression in RASFs. It was noted that HOTTIP could induce SFRP1 promoter methylation through recruitment of Dnmt3b and activate the Wnt signaling pathway. Finally, a rat RA model was established in order to evaluate the in vivo effects of HOTTIP and SFRP1, which suggested that HOTTIP silencing or SFRP1 elevation inhibited the progression of RA in vivo. Our key findings demonstrate the anti-inflammatory ability of HOTTIP silencing in RA through SFRP1 promoter demethylation. These findings support HOTTIP as a candidate anti-arthritis target.

Elevated levels of Secreted-Frizzled-Related-Protein 1 contribute to Alzheimer's disease pathogenesis.

The deposition of aggregated amyloid-β peptides derived from the pro-amyloidogenic processing of the amyloid precurson protein (APP) into characteristic amyloid plaques (APs) is distinctive to Alzheimer's disease (AD). Alternative APP processing via the metalloprotease ADAM10 prevents amyloid-β formation. We tested whether downregulation of ADAM10 activity by its secreted endogenous inhibitor secreted-frizzled-related protein 1 (SFRP1) is a common trait of sporadic AD. We demonstrate that SFRP1 is significantly increased in the brain and cerebrospinal fluid of patients with AD, accumulates in APs and binds to amyloid-β, hindering amyloid-β protofibril formation. Sfrp1 overexpression in an AD-like mouse model anticipates the appearance of APs and dystrophic neurites, whereas its genetic inactivation or the infusion of α-SFRP1-neutralizing antibodies favors non-amyloidogenic APP processing. Decreased Sfrp1 function lowers AP accumulation, improves AD-related histopathological traits and prevents long-term potentiation loss and cognitive deficits. Our study unveils SFRP1 as a crucial player in AD pathogenesis and a promising AD therapeutic target.

SFRP1 exerts effects on gastric cancer cells through GSK3β/Rac1‑mediated restraint of TGFβ/Smad3 signaling.

Secreted frizzled-related protein 1 (sFRP1) is an inhibitor of canonical Wnt signaling; however, previous studies have determined a tumor-promoting function of sFRP1 in a number of different cancer types. A previous study demonstrated that sFRP1 overexpression was associated with an aggressive phenotype and the activation of transforming growth factor β (TGFβ) signaling. sFRP1 overexpression and sFRP1 knockdown cell models were established. Immunoblotting was conducted to examine the protein levels of the associated molecules. Immunofluorescence staining followed by confocal microscopy was performed to visualize the cytoskeleton alterations and subcellular localization of key proteins. sFRP1 overexpression restored glycogen synthase kinase 3β (GSK3β) activity, which activated Rac family small GTPase 1 (Rac1). GSK3β and Rac1 mediated the effect of sFRP1 on the positive regulation of cell growth and migration/invasion. Inhibition of GSK3β or Rac1 abolished the regulation of sFRP1 on TGFβ/SMAD family member 3 (Smad3) signaling and the aggressive phenotype; however, GSK3β or Rac1 overexpression increased cell migration/invasion and restrained Smad3 activity by preventing its nuclear translocation and limiting its transcriptional activity. The present study demonstrated a tumor-promoting function of sFRP1-overexpression by selectively activating TGFβ signaling in gastric cancer cells. GSK3β and Rac1 serve an important function in mediating the sFRP1-induced malignant alterations and signaling changes.

SFRP1 has a biphasic effect on doxorubicin-induced cardiotoxicity in a cellular location-dependent manner in NRCMs and Rats.

Doxorubicin (Dox) is an effective anticancer drug, however, its clinical application is restricted by the life-threatening cardiotoxic effects. Secreted Frizzled-related protein 1 (sFRP1) has been reported to participate in both the cancer and cardiovascular diseases and was one of the differential expression genes in normal hearts compared with Dox-treated hearts. Thus, it is important to reveal the potential role of sFRP1 in Dox-induced cardiotoxicity. Here, we show that sFRP1 has a biphasic effect on Dox-induced cardiotoxicity in a location-dependent manner. The secretion of sFRP1 was significantly increased in Dox-treated neonatal rat cardiomyocytes (NRCMs) (1µM) and SD rats (5mg/kg/injection at day 1, 5, and 9, i.p.). Adding the anti-sFRP1 antibody (0.5µg/ml) and inhibiting sFRP1 secretion by caffeine (5mM) both relieved Dox-induced cardiotoxicity through activating Wnt/β-catenin signaling, whereas increasing the secretion of sFRP1 by heparin (100µg/ml) had the opposite effect. The intracellular level of sFRP1 was significantly decreased after Dox treatment both in vitro and in vivo. Knockdown of sFRP1 by sgRNA aggravated Dox-induced cardiotoxicity, while moderate overexpression of sFRP1 by Ad-sFRP1 exhibited protective effect. Besides, poly(ADP-ribosyl) polymerase-1 (PARP1) was screened as an interacting partner of sFRP1 in NRCMs by mass spectrometry. Our results suggested that the intracellular sFRP1 protected NRCMs from Dox-induced cardiotoxicity by interacting with PARP1. Thus, our results provide a novel evidence that sFRP1 has a biphasic effect on Dox-induced cardiotoxicity. In addition, the oversecretion of sFRP1 might be used as a biomarker to indicate the occurrence of cardiotoxicity induced by Dox treatment.

Effects of secreted frizzled-related protein 1 on proliferation, migration, invasion, and apoptosis of colorectal cancer cells

BackgroundSecreted frizzled-related protein 1 (SFRP1) is a member of the SFRPs family that modulates the Wnt signal transduction pathway. Recent studies have showed down-regulation of SFRP1 expression in colorectal cancer (CRC). We aimed to evaluate the effect of SFRP1 on the proliferation, migration, invasion and apoptosis of CRC cells in vitro.Materials and methodsWe used real-time fluorescence quantification (RT-PCR) and Western blotting to detect SFRP1 expression in CRC, pericarcinomatous tissues and CRC cell lines. We assessed the influence of overexpression and knockdown of SFRP1 on CRC cell proliferation, migration, invasion, and apoptosis, Western blotting was used to evaluate protein levels of Wnt, β-catenin, and apoptosis-related proteins.ResultsThe expression of SFRP1 was significantly decreased in CRC tissues. Among the six CRC cell lines (sw-480, sw1116, caco-2, ht-29, colo-205, and hct-116), RT-PCR revealed that sw1116 cells had the lowest expression of SFRP1, while caco-2 cells had the highest SFRP1 expression. SFRP1 overexpression in sw1116 cells significantly suppressed cell proliferation while SFRP1 knockdown in caco-2 cells significantly increase the cell proliferation. In addition, overexpression of SFRP1 in sw1116 cells remarkedly suppressed cell migration and invasion, whereas knockdown of SFRP1 in caco-2 cells resulted in significant enhancement of migration and invasion. Furthermore, SFRP1 overexpression in sw1116 cells promoted cell apoptosis. Western blotting showed that SFRP1 overexpression significantly decreased the protein levels of Wnt, β-catenin and apoptosis-related proteins, including MMP2, MMP9, Twist, CDK1, TGF, and Bcl2.ConclusionOur results demonstrate that SFRP1 suppresses cell proliferation, migration and invasion, and promotes apoptosis in CRC cells.

Secreted frizzled-related protein 1 overexpression in gastric cancer: Relationship with radiological findings of dual-energy spectral CT and PET-CT

We explored the role of secreted frizzled-related protein 1 (sFRP1) overexpression in gastric cancer and its relationship with radiological findings from dual-energy spectral CT(DEsCT) and positron emission tomography/computed tomography (PET/CT). We established mouse metastatic models using the SGC-7901/sFRP1 gastric cancer cell line. A control group was established using the SGC-7901/vector cell line. The models were then scanned with dual-energy spectral CT and PET-CT. Subsequent analysis, including immunohistochemistry and Transferase-mediated deoxyuridine triphosphate-biotin nick end labelling (TUNEL), was performed to confirm the role of sFRP1. Transwell chamber and angiogenesis assays were conducted to verify the effect of sFRP1 in vitro. We found that the control group showed negative radiological performance with successful implantation. Concurrently, the treated group showed visible lesions, a higher FDG uptake and increasing enhancement. The immunological and histological analysis confirmed the positive radiological performance with larger size, increasing proliferation, more microvessels and less apoptosis. The angiogenic up-regulation of sFRP1 overexpression were further verified with in vitro cell models. This preliminary study demonstrates that sFRP1 overexpression in gastric cancer cells leads to increased cell proliferation and angiogenesis, which may, in turn, contribute to positive PET/CT and CT performances.

MiR-1-3p Suppresses the Proliferation, Invasion and Migration of Bladder Cancer Cells by Up-Regulating SFRP1 Expression

Bladder cancer is of compelling morbidity and mortality due to its high recurrence rate. Little development has been made in the last decades in the therapy methods. Thus, the mechanism of its growth and invasiveness involving novel molecular targets are needed. Our research objective is to confirm the hypothesis that miR-1-3p suppresses the proliferation, invasion and migration of bladder cancer cells. The expression levels of miR-1-3p and SFRP1 were evaluated using RT-qPCR in bladder cancer tissues and cells as well as in normal tissues and cells. J82 cell lines were selected as experiment subjects due to their low expression levels of miR-1-3p. Plasmids carrying miR-1-3p mimics, miR-1-3p inhibitors and SFRP1 were transfected into the J82 cell lines. Subsequently, the protein expression of SFRP1 was detected using Western Blot analysis, and cell proliferation, apoptosis, invasion and migration ability was measured using MTT, the flow cytometry, the Transwell test and wound healing assays, respectively Results: Bladder cancer tissues and cells exhibited significant decrease in the expression of miR-1-3p and SFRP1 compared to normal tissues and cells, and human bladder cancer cell line J82 exhibited the most significant decrease in these expressions (P < 0.05). MiR-1-3p up-regulates SFRP1 expression in bladder cancer cells, and the over-expression of miR-1-3p can suppress the proliferation, invasion and migration ability of bladder cancer cells. This mechanism is similar to the effect of SFRP1 over-expression on bladder cancer cells. MiR-1-3p suppresses the proliferation, invasion and migration of bladder cancer cells by up-regulating SFRP1 expression.

Excess placental secreted frizzled-related protein 1 in maternal smokers impairs fetal growth

Maternal cigarette smoking during pregnancy remains one of the most common and preventable causes of fetal growth restriction (FGR), a condition in which a fetus is unable to achieve its genetically determined potential size. Even though epidemiologic evidence clearly links maternal cigarette smoking with FGR, insight into the molecular mechanisms of cigarette smoke-induced FGR is lacking. Here, we performed transcriptional profiling of placentas obtained from smoking mothers who delivered growth-restricted infants and identified secreted frizzled-related protein 1 (sFRP1), an extracellular antagonist of endogenous WNT signaling, as a candidate molecule. sFRP1 mRNA and protein levels were markedly upregulated (~10-fold) in placentas from smoking mothers compared with those from nonsmokers. In pregnant mice, adenovirus-mediated overexpression of sFRP1 led to FGR, increased karyorrhexis in the junctional zone, and decreased proliferation of labyrinthine trophoblasts. Consistent with our hypothesis that placental WNT signaling is suppressed in maternal smokers, we found that exposure to carbon monoxide analogs led to reduced WNT signaling, increased SFRP1 mRNA expression, and decreased cellular proliferation in a trophoblast cell line. Moreover, administration of carbon monoxide analogs to pregnant mice in late gestation led to FGR. In summary, our results indicate that the increased placental expression of sFRP1 seen in smokers impairs fetal growth by inhibiting WNT signaling and trophoblast proliferation.

MiR-27a regulates Wnt/beta-catenin signaling through targeting SFRP1 in glioma.

Glioma is one of the most common intracranial tumors, and the prognosis is poor, although more and more treatments are employed. Wnt/beta-catenin signaling has been reported to be associated with glioma. SFRP1 acts as an antagonist and inhibits Wnt signaling by binding to Wnt molecules. In the present study, we aimed to investigate miRNA-27a as an antineoplastic factor that inhibits the Wnt/beta-catenin pathway by binding to the SFRP1 3'-UTR in glioma in vitro. We first showed that the expression of miR-27a was elevated in both glioma samples and cell lines. Furthermore, downregulation of miR-27a induced growth inhibition, cycle arrest, and apoptosis, and suppressed invasion/migration in glioma cell lines. Quantitative real-time PCR, western blot, and luciferase assay analysis showed that SFRP1 is a direct target of miR-27a. Overexpression of SFRP1 inhibited the malignancy of glioma cell lines. Our investigation showed that downregulation of miR-27a suppressed beta-catenin/TCF-4 transcription activity by targeting SFRP1. Our findings identify a role for miR-27a in glioma cell viability, cycle, apoptosis, and invasion/migration after activation of Wnt/beta-catenin signaling through SFRP1.

MiR-27a Targets sFRP1 in hFOB Cells to Regulate Proliferation, Apoptosis and Differentiation

MicroRNAs (miRNAs) play a key role in the regulation of almost all the physiological and pathological processes, including bone metabolism. Recent studies have suggested that miR-27 might play a key role in osteoblast differentiation and bone formation. Increasing evidence indicates that the canonical Wnt signaling pathway contributes to different stages of bone formation. In this study, we identify miR-27a can promote osteoblast differentiation by repressing a new target, secreted frizzled-related proteins 1 (sFRP1) expression at the transcriptional level. Here, 21 candidate targets of miR-27a involved in canonical Wnt/β-catenin signaling were predicted, and a significant decrease in sFRP1 luciferase activity was observed both in 293T and MG63 cells co-transfected with the matched luciferase reporter constructs and miR-27a mimic. Furthermore, the presence of exogenous miR-27a significantly decreased sFRP1 mRNA and protein expression in hFOB1.19 cells during both proliferation and osteogenic differentiation. The over-expression of miR-27a or knockdown sFRP1 significantly increased the percentage of apoptotic hFOBs, the percentage of cells in the G2-M phase of the cell cycle and the expression of key osteoblastic markers, including ALP, SPP1, RUNX2 and ALP activity. Over-expression of miR-27a or knockdown of endogenous sFRP1 led to an accumulation of β-catenin in hFOBs. In the present study, we demonstrate that miR-27a induced gene silencing effect is a vital mechanism contributing to bone metabolism in hFOB cells in vitro, which is partly affected by the post-transcriptional regulation of sFRP1, during osteoblast proliferation, apoptosis and differentiation.

A5.12 SFRPS in cartilage biology: more than just WNT antagonists

Background and Objectives Wnts play an important role in cartilage development, homeostasis and degeneration. Therefore, exploring the therapeutic potential of factors that can modulate Wnts is of great interest. Secreted...

Epigenetic silencing ofSFRP1andSFRP5by hepatitis B virus X protein enhances hepatoma cell tumorigenicity through Wnt signaling pathway

Secreted frizzled-related proteins (SFRPs) are antagonists of the Wnt signaling pathway whose epigenetic downregulation have been shown to be involved in hepatocarcinogenesis. However, dysregulation of SFRPs induced by hepatitis B virus (HBV) X protein (HBx) has never been studied in HBV-related hepatocellular carcinoma (HBV-HCC). In this study, we sought to determine the clinical significance and underlying mechanism of HBx-induced SFRPs dysregulation in hepatoma cells and HBV-HCC patients. Our results showed that SFRP1 and SFRP5 expression were dramatically decreased by HBx in hepatoma cells. The repressed expression in hepatoma cells was partially rescued by a DNA methylation inhibitor and synergistically increased by a combination treatment with a histone deacetyltransferases inhibitor. In addition, we identified that SFRP1 and SFRP5 promoters were hypermethylated in both HBx-expressing hepatoma cells and HBV-HCC tissues. Downregulation of SFRP1 and SFRP5 in HBV-HCC tissues was significantly correlated with overexpression of DNA methyltransferase 1 (DNMT1) and poor tumor differentiation. HBx facilitated the binding of DNMT1 and DNMT3A to SFRP1 and SFRP5 promoters, and resulted in epigenetic silencing of SFRP1 and SFRP5. Moreover, overexpression of SFRP1, SFRP5 or RNA interference mediated silencing of DNMT1 inactivated the Wnt signaling pathway and decreased the expression levels of Wnt target genes c-Myc and CyclinD1, thus impeding HCC growth in vitro and in vivo, and regressing HBx-induced epithelial-mesenchymal transition (EMT). Our findings strongly suggest that epigenetic silencing of SFRP1 and SFRP5 by HBx allows constitutive activation of Wnt signaling pathway and hence contributes to hepatocarcinogenesis.

High levels of secreted frizzled-related protein 1 correlate with poor prognosis and promote tumourigenesis in gastric cancer

BackgroundSecreted frizzled-related protein 1 (sFRP1), Wnt signalling regulator, can positively or negatively regulate tumourigenesis and progression. We sought to determine the clinical relevance and the role of sFRP1 in gastric cancer development and progression. MethodsWe investigated the sFRP1 protein expression levels and its clinicopathological correlations using 85 cases of human gastric samples with survival information (JWCI cohort). mRNA levels of sFRP1 and coexpressed genes were analysed using 131-sample cDNA microarray data (Ruijin cohort). The effects of sFRP1 alteration were investigated using cell proliferation, colony formation, migration, and invasion and xenograft models. ResultsWe show that sFRP1 is overexpressed in some human cancers and is significantly associated with lymph node metastasis and decreased overall survival in gastric cancer patients. Using gastric cancer cell models, we demonstrate that sFRP1 overexpression is correlated with the activation of TGFβ (transforming growth factor-beta) signalling pathway and thereby induces cell proliferation, epithelial–mesenchymal transition (EMT), and invasion. Conversely, sFRP1 knockdown shows the opposite effects. Furthermore, sFRP1 overexpression promotes tumourigenesis and metastasis in a xenograft model. ConclusionOur studies demonstrate that sFRP1 is a biomarker for aggressive subgroups of human gastric cancer and a prognostic biomarker for patients with poor survival. Our data provide insight into a crosstalk between Wnt and TGFβ pathways which underlies gastric cancer development and progression.