Secreted Frizzled-related Protein 1 mRNA Research Articles

IL-13–induced STAT3-dependent signaling networks regulate esophageal epithelial proliferation in eosinophilic esophagitis

Basal zone hyperplasia (BZH) and dilated intercellular spaces (DISs) are thought to contribute to the clinical manifestations of eosinophilic esophagitis (EoE); however, the molecular pathways that drive BZH remain largely unexplored. We sought to define the role of IL-13-induced transcriptional programs in esophageal epithelial proliferation in EoE. We performed RNA sequencing, bioinformatics, Western blot, reverse transcriptase quantitative PCR, and histologic analyses on esophageal biopsies from healthy control and patients with EoE, primary esophageal cells derived from patients with EoE, and IL-13-stimulated esophageal epithelial keratinocytes grown at the air-liquid interface (EPC2-ALI). Genetic (shRNA) and pharmacologic (proteolysis-targeting chimera degrader) approaches and invivo model of IL-13-induced esophageal epithelial remodeling (Krt5-rtTA x tetO-IL-13Tg) were used to define the role of signal transducer and activator of transcription 3 (STAT3) and STAT6 and secreted frizzled-related protein 1 (SFRP1) in esophageal epithelial proliferation. RNA-sequencing analysis of esophageal biopsies (healthy control vs EoE) and EPC2-ALI revealed 82 common differentially expressed genes that were enriched for putative STAT3 target genes. Invitro and invivo analyses revealed a link between IL-13-induced STAT3 and STAT6 phosphorylation, SFRP1 mRNA expression, and esophageal epithelial proliferation. Invitro studies showed that IL-13-induced esophageal epithelial proliferation was STAT3-dependent and regulated by the STAT3 target SFRP1. SFRP1 mRNA is increased in esophageal biopsies from patients with active EoE compared with healthy controls or patients in remission and identifies an esophageal suprabasal epithelial cell subpopulation that uniquely expressed the core EoE proinflammatory transcriptome genes (CCL26, ALOX15, CAPN14, ANO1, and TNFAIP6). These studies identify SFRP1 as a key regulator of IL-13-induced and STAT3-dependent esophageal proliferation and BZH in EoE and link SFRP1+ esophageal epithelial cells with the proinflammatory and epithelial remodeling response in EoE.

Abstract LB111: Drug repurposing of niclosamide to regulate Wnt/beta-catenin signaling pathway through upregulating SFRP1 in colorectal cancer

Abstract Aim: This study investigated the inhibition of proliferation and invasiveness of colorectal cancer (CRC) by niclosamide via targeting the secreted Frizzled-related protein 1 (SFRP1) and the Wnt/beta-catenin signaling pathway. Background: CRC is the third most common cancer worldwide. Aberrant activation of various signaling pathways in CRC leads to its poor response to chemotherapy. Hyperactivation of Wnt/beta-catenin pathway is known to drive cell proliferation, invasion, and migration of CRC. Epigenetic silencing of extracellular Wnt inhibitors, such as secreted Frizzled-related proteins (SFRPs), has been shown to stabilize beta-catenin and subsequently activate the Wnt signaling pathway. Niclosamide is a clinically approved drug indicated for the treatment of tapeworm infections. We have recently reported the repurposing of niclosamide to potentiate chemotherapeutic drugs for treating CRC by STAT3 inhibition. Niclosamide was also reported to be a Wnt/beta-catenin inhibitor but the precise mechanism is not clear. Methods: The antiproliferative effect was assessed by MTT assay and colony formation assay. The mRNA level, protein expression, and methylation status of SFRP1, and sets of SFRP1 co-expressed genes in CRC were analyzed by the TCGA data portal. The mRNA expression of SFRP1 and CpG island methylator phenotype (CIMP) marker genes were measured by qRT-PCR. DNA methylation was analyzed by bisulfite genomic sequencing. Inhibition of Wnt/beta-catenin and its downstream targets were examined by Western blot analysis. Cell migration and invasion were investigated by wound healing and transwell chamber migration assay. The intracellular localization of beta-catenin was determined by immunofluorescence assay. Results: Niclosamide inhibited HCT116 cell proliferation and colony formation in a concentration-dependent manner. Compared with normal colon tissues, CRC expressed significantly lower level of SFRP1 mRNA. SFRP1 methylation was inversely correlated with its mRNA expression. The DNA-demethylating agent 5-azacytidine was shown to restore expression of SFRP1 and CIMP panel genes in HCT116 cells after 5-day treatment. However, SFRP1 mRNA level was only upregulated by 1-day niclosamide treatment, but not 3-day niclosamide treatment. The upregulation of SFRP1 by niclosamide was found not relevant to DNA demethylation according to bisulfite genomic sequencing data. Immunofluorescence and Western blotting analysis showed that the increased SFRP1 expression was accompanied by reduced expression and nuclear accumulation of beta-catenin. Moreover, a low concentration of niclosamide that has minimal effect on cell proliferation, was shown to significantly suppress migration and invasion of HCT116 cells. Conclusion: Niclosamide is a promising candidate for drug repurposing. It was shown to upregulate SFRP1 and subsequently suppress Wnt/beta-catenin signaling, thereby impairing CRC cell migration and invasion. Upregulation of SFRP1 by niclosamide was not dependent on DNA demethylation. Citation Format: Mia Mingxia Wu, Christy Wing Sum Tong, Vivi Wei Yan, Kenneth Kin-wah To. Drug repurposing of niclosamide to regulate Wnt/beta-catenin signaling pathway through upregulating SFRP1 in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr LB111.

MBD2 and EZH2 regulate the expression of SFRP1 without affecting its methylation status in a colorectal cancer cell line.

Secreted frizzled-related protein 1 (SFRP1), which is an extracellular inhibitor involved in Wnt signalling, is downregulated by promoter hypermethylation in the early stages of colorectal tumorigenesis. Polycomb (PCG) and methyl-CpG-binding domain (MBD) proteins that serve a role in epigenetic gene regulation. The aim of the present study was to determine the role of PCG and MBD proteins in the regulation of SFRP1 gene expression in colorectal cancer (CRC), specifically in CRC cell lines and the human embryo intestinal mucosa cell line CCC-HIE-2. The methylation status of the SFRP1 gene promoter were analysed using methylation-specific PCR (MSP), whereas SFRP1 mRNA expression was analysed using reverse transcription-quantitative PCR. The association between PCG and MBD proteins and the SFRP1 gene was assessed, where associated proteins were screened by chromatin immunoprecipitation and their expression were subsequently knocked down using RNA interference to determine their role in the regulation of SFRP1 gene expression. The SFRP1 promoter was demonstrated to be hypermethylated in CRC cell lines and partially methylated in the non-cancerous cell line CCC-HIE-2. SFRP1 mRNA expression was significantly lower in CRC cell lines compared with that of CCC-HIE-2 cells. The expression of PCGs enhancer of zeste homolog 2 (EZH2) and BMI1, along with MBD2, was indicated to be upregulated with SFRP1 methylation in HCT116 and SW480 cells. The SFRP1 promoter region was enriched with EZH2 in CCC-HIE-2 cells and enriched with EZH2 and MBD2 in SW480 cells, whereas none of the proteins examined were indicated on the SFRP1 promoter in HCT116 cells. The expression of SFRP1 was reactivated by MBD2 small interfering (si)RNA but not by EZH2 siRNA in SW480 cells, but combined MBD2 and EZH2 knockdown effectively restored SFRP1 gene expression without affecting the methylation status of the SFRP1 promoter. In conclusion, data from the present study revealed that MBD2 and EZH2 regulated SFRP1 expression without affecting the hypermethylation of SFRP1 in CRC cell lines. Instead, the regulation of SFRP1 expression may be through a distinct mechanism, which warrants further investigation.

Circulating methylated RUNX3 and SFRP1 genes as a noninvasive panel for early detection of colorectal cancer.

This study was conducted to assess the methylation status of runt-related transcription factor 3 (RUNX3) and secreted frizzled-related protein 1 (SFRP1) genes in paired tissue and serum samples of colorectal cancer (CRC), adenomatous, and control subjects and elucidate the association between methylation status on RUNX3 and SFRP1 mRNA expression. Methylation status of RUNX3 and SFRP1 in paired tissue and serum samples and RUNX3 and SFRP1 mRNA expression in tissue from 85 patients with CRC, 40 with adenoma, and 40 healthy controls were determined using methylation-specific PCR and reverse transcription PCR. The frequency RUNX3 and SFRP1 genes methylation was significantly higher in both tissues and serum of CRC patients and was significantly associated with absence of its corresponding mRNA expression. The concordance between tissue and serum methylation status was 94.4% for RUNX3 and 94.3% for SFRP1. Tissue RUNX3 methylation status detected CRC with 63.53% sensitivity and 80.00% specificity, while serum RUNX3 methylation status detected CRC with 60.00% sensitivity and 82.50% specificity. Tissue SFRP1 methylation status showed a sensitivity of 82.35% and specificity of 65.00%, while serum SFRP1 methylation status showed a sensitivity of 77.65% and specificity of 70.00% in detection of CRC. RUNX3/SFRP1/carcinoembryonic antigen (CEA) panel identified CRC with sensitivity of 89.41% in tissue and 84.71% in serum. Our results verified the reliability of using serum RUNX3 and SFRP1 methylation status as a noninvasive biomarker for diagnosis of CRC and that combined detection of RUNX3/SFRP1/CEA panel might be a promising strategy for early detection of CRC.

MiR-1180 from bone marrow-derived mesenchymal stem cells induces glycolysis and chemoresistance in ovarian cancer cells by upregulating the Wnt signaling pathway.

Bone marrow-derived mesenchymal stem cells (BM-MSCs) play an important role in cancer development and progression. However, the mechanism by which they enhance the chemoresistance of ovarian cancer is unknown. Conditioned media of BM-MSCs (BM-MSC-CM) were analyzed using a technique based on microRNA arrays. The most highly expressed microRNAs were selected for testing their effects on glycolysis and chemoresistance in SKOV3 and COC1 ovarian cancer cells. The targeted gene and related signaling pathway were investigated using in silico analysis and in vitro cancer cell models. Kaplan-Merier survival analysis was performed on a population of 59 patients enrolled to analyze the clinical significance of microRNA findings in the prognosis of ovarian cancer. MiR-1180 was the most abundant microRNA detected in BM-MSC-CM, which simultaneously induces glycolysis and chemoresistance (against cisplatin) in ovarian cancer cells. The secreted frizzled-related protein 1 (SFRP1) gene was identified as a major target of miR-1180. The overexpression of miR-1180 led to the activation of Wnt signaling and its downstream components, namely Wnt5a, β-catenin, c-Myc, and CyclinD1, which are responsible for glycolysis-induced chemoresistance. The miR-1180 level was inversely correlated with SFRP1 mRNA expression in ovarian cancer tissue. The overexpressed miR-1180 was associated with a poor prognosis for the long-term (96-month) survival of ovarian cancer patients. BM-MSCs enhance the chemoresistance of ovarian cancer by releasing miR-1180. The released miR-1180 activates the Wnt signaling pathway in cancer cells by targeting SFRP1. The enhanced Wnt signaling upregulates the glycolytic level (i.e. Warburg effect), which reinforces the chemoresistance property of ovarian cancer cells.

Methylation of secreted frizzled-related protein 1 (SFRP1) promoter downregulates Wnt/β-catenin activity in keloids.

Keloid, a benign skin disorder, forms during wound healing in genetically susceptible individuals. To better control keloid and understand the molecular mechanisms, this study screened gene hypermethylations of GEO database microarray data on keloids and identified the hypermethylation of the secreted frizzled related protein-1 (SFRP1) promoter. Subsequently, hypermethylation and mRNA and protein levels were assessed in 57 cases of keloid vs. normal skin tissues. Fibroblasts from tissues were isolated for the assessment of gene regulation in vitro. The methods used were bioinformatic analysis, lentiviral infection carrying SFRP1 cDNA, qRT-PCR, western blot, immunohistochemistry, luciferase reporter assay, methylation-specific PCR and methylated DNA immunoprecipitation-qPCR, ELISA, and/or 5-Aza-2'-deoxycytidine treatment. The data revealed that the SFRP1 promoter was hypermethylated in keloid tissues, compared with that in normal skin tissues. The SFRP1 promoter methylation contributed to the downregulation of SFRP1 mRNA and protein in keloid tissues and keloid fibroblasts. The 5-Aza treatment significantly upregulated SFRP1 mRNA and protein level in keloid fibroblasts. Furthermore, the knockdown of DNMT1 expression, and not the expression of DNMT3a or DMNT3b, was responsible for the hypermethylation of the SFRP1 promoter and upregulation of SFRP1 mRNA and protein in keloid fibroblasts. In addition, the infection of lentivirus carrying SFRP1 cDNA significantly inhibited the signaling activity of Wnt/β-catenin and the mRNA and protein expression of β-catenin and α-SMA in keloid fibroblasts. In summary, the lost SFRP1 expression-induced Wnt/β-catenin signaling due to the hypermethylation of the SFRP1 promoter could associate with keloid development, suggesting that SFRP1 might be a therapeutic target for keloid treatment.

Effects of supplementation with nondigestible carbohydrates on fecal calprotectin and on epigenetic regulation of SFRP1 expression in the large-bowel mucosa of healthy individuals ,

Background: Hyperactive Wnt signaling is frequently observed in colorectal cancer. Higher intakes of dietary fiber [nondigestible carbohydrates (NDCs)] and the fermentation product butyrate are protective against colorectal cancer and may exert their preventative effects via modulation of the Wnt pathway.Objectives: We investigated the effects of supplementing healthy individuals with 2 NDCs [resistant starch (RS) and polydextrose] on fecal calprotectin concentrations and Wnt pathway–related gene expression. In addition, we determined whether effects on secreted frizzled-related protein 1 (SFRP1) expression are mediated via the epigenetic mechanisms DNA methylation and microRNA expression.Design: In a randomized, double-blind, placebo-controlled trial (the Dietary Intervention, Stem cells and Colorectal Cancer (DISC) Study), 75 healthy participants were supplemented with RS and/or polydextrose or placebo for 50 d in a 2 × 2 factorial design. Pre- and postintervention stool samples and rectal mucosal biopsies were collected and used to quantify calprotectin and expression of 12 Wnt-related genes, respectively. The expression of 10 microRNAs predicted to target SFRP1 was also quantified by quantitative reverse transcriptase-polymerase chain reaction, and DNA methylation was quantified at 7 CpG sites within the SFRP1 promoter region by pyrosequencing.Results: NDC supplementation did not affect fecal calprotectin concentration. SFRP1 mRNA expression was reduced by both RS (P = 0.005) and polydextrose (P = 0.053). RS and polydextrose did not affect SFRP1 methylation or alter the expression of 10 microRNAs predicted to target SFRP1. There were no significant interactions between RS and polydextrose.Conclusions: RS and polydextrose supplementation did not affect fecal calprotectin concentrations. Downregulation of SFRP1 with RS and polydextrose could result in increased Wnt pathway activity. However, effects on Wnt pathway activity and downstream functional effects in the healthy large-bowel mucosa remain to be investigated. The DISC Study was registered at clinicaltrials.gov as NCT01214681.

MicroRNA-27a Promotes the Proliferation and Invasiveness of Colon Cancer Cells by Targeting SFRP1 through the Wnt/β-Catenin Signaling Pathway

This study aims to explore the effects of microRNA-27a (miR-27a) on the proliferation and invasiveness of colon cancer cells through the Secreted Frizzled-related protein 1 (SFRP1) and the Wnt/β-catenin signaling pathway. Colon cancer tissues and adjacent normal tissues from 125 colon cancer patients, together with the HCEpic, HCT-116, HT-29, SW480 and SW620 cell lines, were prepared for this study. The transfected HCT-116 cells were divided into the miR-27a mimics, miR-27a-NC, anti-miR-27a, blank, Lv-SFRP1, Lv-NC, and miR-27a mimics + Lv-SFRP1 groups. RT-qPCR was performed to detect the expressions of miR-27a and SFRP1 mRNA. A dual-luciferase reporter assay was conducted to examine the effect of miR-27a on SFRP1. Western blotting was used to measure the expressions of the SFRP1, β-catenin, GSK-3β, p-β-catenin, p-GSK-3β, c-Myc and cyclin D1 proteins. MTT, soft agar clone formation and Transwell chamber assays were performed to detect cell proliferation and invasion. Compared with normal tissues and cells, colon cancer tissues and cells demonstrated significantly higher expression of miR-27a, but lower expressions of SFRP1 mRNA and protein. MiR-27a negatively regulated the expression of SFRP1 mRNA. SFRP1 was also found to be a target gene of miR-27a. In the miR-27a mimic group, the proliferation and invasiveness of colon cancer cells were significantly increased, while the expressions of GSK-3 β and p-β-catenin were remarkably down-regulated; in contrast, the expressions of p-GSK-3β, -catenin, c-Myc and cyclin D1 were up-regulated. While the proliferation and invasiveness of colon cancer cells in the anti-miR-27a and Lv-SFRP1 groups were decreased, the expressions of GSK-3β and p-β-catenin were elevated, and the expressions of p-GSK-3β, β-catenin, c-Myc and cyclin D1 were decreased. These findings indicated that miR-27a could promote the proliferation and invasiveness of colon cancer cells by targeting SFRP1 through the Wnt/β-catenin signaling pathway.

Abstract A16: Different epigenetic mechanisms involved in the regulation of SFRP1 gene in prostate cancer

Abstract Among men, prostate cancer (PCa)[1] is the second most common cancer and the fifth cause of death worldwide [2]. Androgens play an important role in the development of the disease. For advanced PCa the standard therapy is androgen depletion. However, after 2 or 3 years a high percentage of patients become resistant to this therapy and castration resistant prostate cancer (CRPC) is developed. There is no successful treatment for CRPC, leading into death [3, 4]. Wingless pathway (WNT) is aberrantly activated in several cancer types and in PCa it is involved in AR activity modulation, promoting cancer development [5]. Secreted Frizzled Related Protein 1 (SFRP1) is commonly known as a WNT inhibitor and generally proposed as a tumor suppressor gene. SFRP1 can exert its tumor suppressor activity by inhibiting the AR transcriptional activity [6]. Usually in cancer, SFRP1 mRNA is down regulated and this is associated to increased DNA methylation at its promoter region [7]. In contrast, in PCa there are different reports suggesting SFRP1 repression in absence of DNA methylation [8]. In this work we aimed to investigate two different epigenetic mechanisms for SFRP1 silencing in PCa. For the in vitro model, we used normal prostate cells RWPE-1 and PCa cell lines: LNCaP, 22RV1 and PC3. We confirmed the correlation between mRNA expression loss and the increased DNA methylation of SFRP1 only in PC3 cells, but not in LNCaP and 22RV1, were instead of DNA methylation we found enrichment of H3K27me3, the Polycomb Repressive Complex 2 (PRC2) mark. To correlate this findings, we analyzed the expression of SFRP1 in fresh frozen tissue samples, 11 primary PCa, 10 Benign Prostatic Hyperplasia (BPH) and 4 normal prostates (NP). We found SFRP1 downregulation in all PCa and BPH samples compared to Normal Prostate, but DNA methylation was increased only in PCa but not in BPH, this suggests a novel repressive mechanism for SFRP1 independent of DNA methylation. To see if AR has a role in regulating mRNA SFRP1 expression, we silenced AR with a siRNA, but no SFRP1 expression levels were modified, so we concluded AR was not directly involved in SFRP1 regulation. All these data together suggest different repression mechanisms for SFRP1, one depending on DNA methylation and another one depending on H3K27me3 PRC2 repressive mechanism, Androgen receptor is not directly involved in SFRP1 downregulation, so other factors might be involved in SFRP1 expression loss in PCa.

Expression Patterns of the Wnt Pathway Inhibitors Dickkopf3 and Secreted Frizzled-Related Proteins 1 and 4 in Endometrial Endometrioid Adenocarcinoma: An NRG Oncology/Gynecologic Oncology Group Study.

The aim of the study was to determine the differential expression patterns of the wingless-type (Wnt) pathway inhibitors Dkk3 (Dickkopf 3), SFRP1 (secreted frizzled-related protein 1), and SFRP4 in normal müllerian tissue and endometrial endometrioid adenocarcinoma specimens. Messenger RNA (mRNA) and protein levels of the Wnt pathway inhibitors Dkk3, SFRP1, and SFRP4 were evaluated by real-time reverse transcription-polymerase chain reaction and Western blot analysis. A total of 87 human tissue specimens were obtained from 60 women who participated in Gynecologic Oncology Group protocol 210. Twenty-seven normal müllerian tissues, 32 early-stage, and 28 advanced-stage endometrial endometrioid cancer specimens were analyzed. Median age for this cohort was 60 years, with median body mass index of 32 kg/m. There was a difference in Dkk3 protein expression between normal müllerian tissues and primary endometrial endometrioid adenocarcinoma samples (P = 0.05). There was down-regulation of Dkk3, SFRP1, and SFRP4 mRNA expression in patients with high-grade disease (P = 0.08, 0.06, and 0.05, respectfully). Furthermore, a decrease in SFRP1 and SFPR4 mRNA expression was noted in patients with a diagnosis of locoregional and distant disease recurrence. Lastly, a trend toward decreased progression-free survival in patients with low Dkk3, SFRP1, and SFRP4 mRNA expression levels was noted. Wnt pathway inhibitor (Dkk3, sFRP1, and/or sFRP4) expression was down-regulated in patients with high-grade disease and was associated with locoregional and distant disease recurrence. Despite sample size (power) limitations, these results support previous preclinical studies and may suggest a therapeutic role for Wnt signaling in endometrial cancer.

Aging related methylation influences the gene expression of key control genes in colorectal cancer and adenoma

AIMTo analyze colorectal carcinogenesis and age-related DNA methylation alterations of gene sequences associated with epigenetic clock CpG sites.METHODSIn silico DNA methylation analysis of 353 epigenetic clock CpG sites published by Steve Horvath was performed using methylation array data for a set of 123 colonic tissue samples [64 colorectal cancer (CRC), 42 adenoma, 17 normal; GEO accession number: GSE48684]. Among the differentially methylated age-related genes, secreted frizzled related protein 1 (SFRP1) promoter methylation was further investigated in colonic tissue from 8 healthy adults, 19 normal children, 20 adenoma and 8 CRC patients using bisulfite-specific PCR followed by methylation-specific high resolution melting (MS-HRM) analysis. mRNA expression of age-related “epigenetic clock” genes was studied using Affymetrix HGU133 Plus2.0 whole transcriptome data of 153 colonic biopsy samples (49 healthy adult, 49 adenoma, 49 CRC, 6 healthy children) (GEO accession numbers: GSE37364, GSE10714, GSE4183, GSE37267). Whole promoter methylation analysis of genes showing inverse DNA methylation-gene expression data was performed on 30 colonic samples using methyl capture sequencing.RESULTSFifty-seven age-related CpG sites including hypermethylated PPP1R16B, SFRP1, SYNE1 and hypomethylated MGP, PIPOX were differentially methylated between CRC and normal tissues (P < 0.05, Δβ ≥ 10%). In the adenoma vs normal comparison, 70 CpG sites differed significantly, including hypermethylated DKK3, SDC2, SFRP1, SYNE1 and hypomethylated CEMIP, SPATA18 (P < 0.05, Δβ ≥ 10%). In MS-HRM analysis, the SFRP1 promoter region was significantly hypermethylated in CRC (55.0% ± 8.4 %) and adenoma tissue samples (49.9% ± 18.1%) compared to normal adult (5.2% ± 2.7%) and young (2.2% ± 0.7%) colonic tissue (P < 0.0001). DNA methylation of SFRP1 promoter was slightly, but significantly increased in healthy adults compared to normal young samples (P < 0.02). This correlated with significantly increased SFRP1 mRNA levels in children compared to normal adult samples (P < 0.05). In CRC tissue the mRNA expression of 117 age-related genes were changed, while in adenoma samples 102 genes showed differential expression compared with normal colonic tissue (P < 0.05, logFC > 0.5). The change of expression for several genes including SYNE1, CLEC3B, LTBP3 and SFRP1, followed the same pattern in aging and carcinogenesis, though not for all genes (e.g., MGP).CONCLUSIONSeveral age-related DNA methylation alterations can be observed during CRC development and progression affecting the mRNA expression of certain CRC- and adenoma-related key control genes.

Expression of secreted frizzled related protein 1, β-catenin and E-cadherin in colorectal carcinoma and its clinicopathological significances

To investigate the expression of secreted frizzled-related protein 1 (SFRP1), β-catenin and E-cadherin in colorectal carcinoma and its clinicopathological significance. The expression of SFRP1, β-catenin and E-cadherin mRNA and protein in tumor and pericancerous tissue samples from 60 cases of colorectal cancer was assayed by reverse-transcription PCR and immunohistochemistry, respectively. The correlation of their expression with clinicopathological factors of colorectal cancer was analyzed. In 52/60 cases the relative mRNA expression of SFRP1 in cancer tissue and pericancerous tissue was 0.4837±0.1532 and 0.7170 ±0.1830; for β-catenin was 0.9293± 0.3705 and 0.6469±0.3166; and for E-cadherin was 0.5556±0.2535 and 0.9422±0.2372 (P<0.01), respectively. SFRP1 mRNA expression was associated with lymphatic metastasis (P<0.05). The positive rate of SFRP1 in colorectal cancer was 31.67% (19/60), and was significantly lower than that in pericancerous colorectal mucosa (75.00%, 45/60). No relationship between SFRP1 protein expression and clinical pathology was found. Abnormal expression rates of β-catenin and E-cadherin in colorectal cancer were 75.00% (45/60) and 58.33% (35/60), respectively, which were significantly higher than that in pericancerous colorectal mucosa (1.67% and 6.67%), respectively. Abnormal β-catenin and E-cadherin expression was associated with tumor differentiation, lymphatic metastasis and Duke's staging. SFRP1 protein expression was negatively correlated with β-catenin and E-cadherin expression (r=-0.517, -0.442, Ps<0.01). Down-regulation of SFRP1 in colorectal cancer may cause abnormal Wnt signaling and induce abnormal β-catenin and E-cadherin expression, indicating that SFRP1 might be involved in the development and progression of colorectal cancer, and could be a novel therapeutic target for colorectal cancer.

Methylation and aberrant expression of the Wnt antagonist secreted Frizzled-related protein 1 in bladder cancer

The aims of this study were to determine the methylation and expression status of secreted Frizzled-related protein 1 (SFRP1) in bladder cancer, to explore the mechanisms involved and to study the role of SFRP1 in the pathogenesis of bladder cancer. SFRP1 mRNA was detected by reverse transcription PCR (RT-PCR). The DNA methylation status was determined by methylation-specific PCR and protein was detected using western blotting. The results of the present study demonstrated that SFRP1 was methylated in the bladder cancer cell lines T24 and 5637, but not in SCaBER cells. After treating T24 and 5637 cells with a demethylating agent, the cells expressed SFRP1 mRNA and protein. Among the 45 patients with bladder cancer, methylation of SFRP1 was detected in 28 patients (62.2%). Of the matched cancer-adjacent tissues, 6 (13.3%) were found to have methylated SFRP1. The result is statistically significant (P<0.01). In conclusion, SFRP1 is downregulated in certain bladder cancer patients as a consequence of methylation. SFRP1 methylation may be involved in the pathogenesis of bladder cancer via excessive activation of the Wnt signaling pathway.

Epigenetic Inactivation of the SFRP1 Gene in Esophageal Squamous Cell Carcinoma

The secreted frizzled-related protein 1 (SFRP1) gene, as a Wnt signaling modulator, is frequently inactivated by promoter methylation in many tumors including gastric cancer, breast cancer, oral squamous cell carcinoma, and esophageal adenocarcinoma. However, the role of SFRP1 in esophageal squamous cell carcinoma (ESCC) is not clear. In this study, we investigated the epigenetic inactivation of the SFRP1 gene in ESCC. Nine ESCC cell lines, two immortalized human esophageal epithelial cell lines, twenty ESCC tissues, and paired adjacent nontumor tissues were analyzed in the study. Methylation-specific polymerase chain reaction (PCR), bisulfite sequencing, reverse-transcription PCR, immunohistochemistry, and chromatin immunoprecipitation assay were used to detect SFRP1 promoter methylation, expression of the SFRP1 gene, and histone modification in the SFRP1 promoter region. The SFRP1 promoter was found to be highly methylated in 95% (19/20) of the ESCC tissues and in nine ESCC cell lines, compared with 65% (13/20) of the paired nontumor tissues. Moreover, we confirmed that complete methylation of the SFRP1 gene promoter was correlated with its greatly reduced expression level. After individual treatment with 5-aza-2'-deoxycytidine (DAC) and trichostatin A (TSA), the messenger RNA (mRNA) level of the SFRP1 gene was not obviously rescued in the EC9706 cell line. Combined incubation with DAC and TSA can, however, substantially increase the SFRP1 mRNA expression level in the EC9706 cell line. Chromatin immunoprecipitation assay showed that acetylated histone H3 and H4 were found in the SFRP1 promoter region. Promoter hypermethylation of SFRP1 is a frequent event in ESCC. Promoter methylation and histone acetylation may cooperatively regulate expression of the SFRP1 gene.

Hypermethylation and aberrant expression of Wnt antagonist secreted frizzled-related protein 1 in gastric cancer

To identify the methylation of secreted frizzled-related protein 1 (SFRP1) in gastric cancer and to investigate the aberrant expression of SFRP1 and its correlation with the clinical pathological features of patients. We determined SFRP1 methylation and SFRP1 mRNA expression in 3 gastric cancer cell lines SGC-7901, BGC-823, HGC-27, from 52 primary gastric cancer specimens and matched tumor adjacent tissue specimens by methylation-specific (MSP) PCR and RT-PCR respectively. Fisher's exact test was used to analyze the statistical association between clinical pathological data and aberrant expression of SFRP1. In 3 cancer cell lines, BGC-823 and HGC-27 had methylated SFRP1 and lost SFRP1 mRNA expression. After treatment of BGC-823 and HGC-27 with the demethylating agent, 5-aza-2'-deoxycytidine, SFRP1 was re-expressed. In 52 primary gastric cancer specimens and matched tumor adjacent tissue specimens, hypermethylation of SFRP1 was detected in 23 (44%) and 8 (15%) specimens respectively (chi(2) = 10.34, P < 0.01). Loss of SFRP1 expression was detected in 17(33%) and 6 (12%) specimens respectively (chi(2) = 6.75, P < 0.01). There was a significant correlation between SFRP1 hypermethylation and SFRP1 expression loss. SFRP1 expression was also correlated significantly with tumor stage and lymph node status, but not with patient sex, age and histological type. SFRP1 inactivation is a common and early event caused mainly by hypermethylation in gastric cancer. SFRP1 expression loss may be correlated with tumor metastasis in primary gastric cancer.

Epigenetic suppression of secreted frizzled related protein 1 (SFRP1) expression in human breast cancer

Expression of Secreted frizzled related protein 1 (SFRP1), a recently identified tumor suppressor gene encoding a WNT signaling antagonist, has been found to be frequently down-regulated in breast cancer and is associated with disease progression and poor prognosis. Here, we investigated the role of epigenetic silencing of SFRP1 in breast cancer cell lines and primary breast tumors. Through analyses by methylation-specific PCR and bisulfite sequencing, promoter methylation of SFRP1 was detected in 88% (7/8) of breast cancer cell lines, 17% (1/6) of grade 1 of ductal carcinoma in situ (DCIS), 69% (9/13) of grade 2 and 3 of DCIS, 68% (19/28) of invasive ductal carcinomas (IDC) and 33% (6/18) of lobular carcinomas but not in any (0/14) of normal mammoplasty specimens and mammary epithelial organoids examined. Real-time RT-PCR studies indicated that loss or down-regulation of SFRP1 expression in tumors is frequently associated with promoter hypermethylation. In addition, breast cancer cell lines with SFRP1 promoter hypermethylation re-expressed SFRP1 mRNA after treatment with 5-azaC, implying that DNA methylation is the predominant epigenetic mechanism for SFRP1 gene silencing. These findings suggest that frequent down-regulation of SFRP1 expression in breast cancer can be attributed, in large part, to aberrant promoter hypermethylation in conjunction with or without histone deacetylation. Based on the frequency of tumor-specific hypermethylation in this gene, SFRP1 could provide a valuable marker for breast cancer.

Loss of SFRP1 is associated with breast cancer progression and poor prognosis in early stage tumors

Aberrant activation of the Wnt signaling pathway plays an important role in the development of solid tumors such as breast and colon cancer. Secreted Frizzled-related protein 1 (SFRP1) is a negative regulator of the Wnt pathway. It has been described that SFRP1 mRNA is strongly down-regulated in breast cancer and a putative tumor suppressor function has been postulated. We have generated and characterized an SFRP1 specific antibody to analyze its expression on protein level and to investigate the association of SFRP1 expression with clinicopathological parameters and patient survival. Analysis of >2000 invasive breast tumors and 56 carcinoma in situ revealed similar frequencies of SFRP1 loss in these tumors (46% and 43% respectively). Therefore, we propose that loss of SFRP1 expression is an early event in breast tumorigenesis. SFRP1 expression was inversely correlated with tumor stage (p<0.001) but not with tumor grade (p=0.14) or lymph node status (p=0.84). Performing a multivariate analysis we could confirm the association between tumor stage and SFRP1 expression (p=0.029). In particular, loss of SFRP1 expression in early stage breast tumors (pT1) was associated with poor prognosis (p=0.04). In conclusion, expression of SFRP1 is commonly lost in breast cancer. SFRP1 expression might be useful as a novel prognostic marker in early stage breast cancer.

WNT pathway and mammary carcinogenesis: loss of expression of candidate tumor suppressor gene SFRP1 in most invasive carcinomas except of the medullary type.

Secreted Frizzled-related protein 1 (SFRP1) encodes a member of a protein family that contains a cysteine-rich domain similar to the WNT-binding site of Frizzled receptors and regulates the WNT pathway. The WNT pathway is frequently altered in human cancers. We have defined the pattern of SFRP1 mRNA expression in the progression of breast cancer. We show that SFRP1 is expressed in the epithelial component of normal breast, in the in situ component of ductal carcinomas and is lost in more than 80% of invasive breast carcinomas except the medullary type. Loss of SFRP1 expression is correlated with the presence of hormonal receptors. Conversely, the maintenance of SFRP1 in carcinomas is correlated with the presence of lymphoplasmocytic stroma. No significant association was observed between SFRP1 status and the level of apoptosis in tumoral cells.