Coexpression of SFRP1 and WIF1 as a prognostic predictor of favorable outcomes in patients with colorectal carcinoma

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.

Prostate Cancer Secretome and Membrane Proteome from Pten Conditional Knockout Mice Identify Potential Biomarkers for Disease Progression

Prostate cancer (PCa) is the second most common cause of mortality among men. Tumor secretome is a promising strategy for understanding the biology of tumor cells and providing markers for disease progression and patient outcomes. Here, transcriptomic-based secretome analysis was performed on the PCa tumor transcriptome of Genetically Engineered Mouse Model (GEMM) Pb-Cre4/Pten^f/f mice to identify potentially secreted and membrane proteins—PSPs and PMPs. We combined a selection of transcripts from the GSE 94574 dataset and a list of protein-coding genes of the secretome and membrane proteome datasets using the Human Protein Atlas Secretome. Notably, nine deregulated PMPs and PSPs were identified in PCa (DMPK, PLN, KCNQ5, KCNQ4, MYOC, WIF1, BMP7, F3, and MUC1). We verified the gene expression patterns of Differentially Expressed Genes (DEGs) in normal and tumoral human samples using the GEPIA tool. DMPK, KCNQ4, and WIF1 targets were downregulated in PCa samples and in the GSE dataset. A significant association between shorter survival and KCNQ4, PLN, WIF1, and F3 expression was detected in the MSKCC dataset. We further identified six validated miRNAs (mmu-miR-6962-3p, mmu-miR- 6989-3p, mmu-miR-6998-3p, mmu-miR-5627-5p, mmu-miR-15a-3p, and mmu-miR-6922-3p) interactions that target MYOC, KCNQ5, MUC1, and F3. We have characterized the PCa secretome and membrane proteome and have spotted new dysregulated target candidates in PCa.

Quercetin potentiates 5-fluorouracil effects in human colon cancer cells through targeting the Wnt/β-catenin signalling pathway: the role of miR-27a

INTRODUCTION

5-fluorouracil (5-FU) is the most widely used chemotherapeutic drug in treating colorectal cancer. However, its toxicity to normal tissues and tumour resistance are the main hurdles to efficient cancer treatment. MiR27-a promotes the proliferation of colon cancer cells by stimulating the Wnt/β-catenin pathway. The present study was conducted to examine whether quercetin (Q) combined with 5-FU improves the anti-proliferative effect of 5-FU on HCT-116 and Caco-2 cell lines through detection of the miR-27a/Wnt/β-catenin signalling pathway.

MATERIAL AND METHODS

Cell viability in HCT-116 and Caco-2 cell lines following quercetin and 5-FU treatment alone and in combination for 48 hours was determined using the MTT assay. The flow cytometry, quantitative real-time polymerase chain reaction, and ELISA techniques were used.

RESULTS

Our results showed that combination of quercetin and 5-FU exhibited greater cytotoxic efficacy than did 5-FU alone. Co-administration of both drugs either in combination 1 (1 : 1 Q: 5-FU) or in combination 2 (1 : 0.5 Q: 5-FU) enhanced apoptosis in HCT-116 and Caco-2 cells compared with 5-FU alone and significantly inhibited the expression of miR-27a, leading to upregulation of secreted frizzled-related protein 1 and suppression of Wnt/β-catenin signalling, which was confirmed by a significant decrease in cyclin D1 expression.

CONCLUSIONS

Quercetin strongly enhanced 5-FU sensitivity via suppression of the miR-27a/Wnt/β-catenin signalling pathway in CRC, which advocates further research of this combination with the lower dose of 5-FU.

Toward Colorectal Cancer Biomarkers: The Role of Genetic Variation, Wnt Pathway, and Long Noncoding RNAs

Colorectal cancer (CRC) is the third leading cause of death worldwide, comprising nearly 8% of cancer-related deaths per year. In South Korea, for example, CRC is the second most common cancer in men, and third in women. This study reports on the association of CRC with genetic variations in long noncoding RNAs, activators, and inhibitors of a cell proliferation pathway. Five normal colon mucosa tissue samples and their matched five-stage IV CRC samples were evaluated (dataset Gene Expression Omnibus accession: GSE50760). We identified more than 5000 differentially expressed genes (DEGs). The Wnt pathway had the greatest portion of DEGs, including activators, inhibitors, and associated long noncoding RNAs (lncRNAs), suggesting the importance of Wnt pathway in CRC. The following genes were aberrantly expressed: WIF1, SFRP4, CD82, WNT2, WNT3, WNT5A, HOTAIR, CRNDE, and UCA1. Notably, HOTAIR is known to silence WIF1, and WIF1 inhibits the Wnt ligands to negatively regulate the pathway. The lncRNA CRNDE positively regulates WNT5A, while UCA1 positively regulates WNT2 and WNT3. We note that HOTAIR was unable to silence WIF1. CRNDE and UCA1 were found to be upregulated, which may explain the high expression of the WIF1 targets. Furthermore, 10 single-nucleotide polymorphisms (SNPs) were identified in five of the candidate genes above. A possible novel SNP in CD82, chr11:44619242T > C, was predicted to introduce a ZBTB7A binding site. These SNPs are hypothesized to contribute to aberrant and discrepant regulation of the Wnt pathway in a context of CRC pathogenesis. These findings collectively inform future research on diagnostics and therapeutics innovation in CRC.

Epigenetics of SFRP1: The Dual Roles in Human Cancers

Secreted frizzled-related protein 1 (SFRP1) is a gene that belongs to the secreted glycoprotein SFRP family. SFRP1 has been classified as a tumor suppressor gene due to the loss of expression in various human cancers, which is mainly attributed by epigenetic inactivation via DNA methylation or transcriptional silencing by microRNAs. Epigenetic silencing of SFRP1 may cause dysregulation of cell proliferation, migration, and invasion, which lead to cancer cells formation, disease progression, poor prognosis, and treatment resistance. Hence, restoration of SFRP1 expression via demethylating drugs or over-expression experiments opens the possibility for new cancer therapy approach. While the role of SFRP1 as a tumor suppressor gene is well-established, some studies also reported the possible oncogenic properties of SFRP1 in cancers. In this review, we discussed in great detail the dual roles of SFRP1 in cancers-as tumor suppressor and tumor promoter. The epigenetic regulation of SFRP1 expression will also be underscored with additional emphasis on the potentials of SFRP1 in modulating responses toward chemotherapeutic and epigenetic-modifying drugs, which may encourage the development of novel drugs for cancer treatment. We also present findings from clinical trials and patents involving SFRP1 to illustrate its clinical utility, extensiveness of each research area, and progression toward commercialization. Lastly, this review provides directions for future research to advance SFRP1 as a promising cancer biomarker.

Hypermethylated Promoters of Secreted Frizzled-Related Protein Genes are Associated with Colorectal Cancer

Colorectal cancer (CRC) is one of the leading causes of death worldwide. Aberrant DNA methylation has been recognized as one of the most common molecular alterations in CRC. The goal of this study was to investigate the diagnostic value of SFRP1 and SFRP2 methylation for CRC. A total of 80 pairs of CRC patients were recruited to test the association of SFRP1 and SFRP2 promotor methylation with CRC. Methylation assay was performed using quantitative methylation-specific polymerase chain reaction (qMSP) method. In this study, we found the methylation levels of SFRP1 and SFRP2 in CRC tumor tissues were significantly higher than those in the adjacent non-tumor tissues (SFRP1: P = 2E-5; SFRP2: P = 0.014). Further bioinformatics analysis of TCGA data confirmed the association of the two genes with CRC (SFRP1: P = 7E-21; SFRP2: P = 5E-24). Luciferase reporter gene assay showed that the recombinant plasmids with SFRP1 and SFRP2 fragments could significantly enhance promoter activity (SFRP1: P = 0.002; SFRP2: P = 0.004). In addition, SFRP1 and SFRP2 methylation were inversely correlated with the mRNA expression displayed by TCGA data mining (SFRP1: r = -0.432, P = 4E-11; SFRP2: r = -0.478, P = 1E-13). GEO data analysis indicated that SFRP1 and SFRP2 expression were increased in three CRC cell lines (COLO320, HCT116 and HT29) after 5'-AZA-deoxycytidine treatment, suggesting that DNA methylation played an important role in regulating gene expression of the two genes. Our results confirmed that promoter methylation of SFRP1 and SFRP2 contributed to the risk of CRC.

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

Background

Secreted 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 methods

We 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.

Results

The 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.

Conclusion

Our results demonstrate that SFRP1 suppresses cell proliferation, migration and invasion, and promotes apoptosis in CRC cells.

Correlation of Wnt antagonist sFPR1, Slug and β-catenin with prognosis and metastasis in colorectal carcinoma

sFPR1 plays an important role in colorectal carcinoma (CRC) tumorigenesis, Slug is also considered to be related to the development of CRC. However, the relationship between them and the mechanism of their involvement in CRC metastasis remain unknown. In this study, immunohistochemistry (IHC) was used to detect the expression of sFPR1, β-catenin, and Slug in 145 samples of CRC and corresponding surrounding "normal" mucosa tissues. Furthermore, clinicopathological features such as age, sex and so on were also collected retrospectively. Western blot and Transwell were used to detect proteins expression and migration capacity. In present study, the expression of sFPR1, Slug and β-catenin proteins were significantly correlated with lymph node metastasis and tumor-node-metastasis (TNM) stage of patients with CRC. sFPR1 expression showed a negative correlation with Slug and β-catenin. Kaplan-Meier analysis indicated that the postoperative 5-year OS of patients was related to the expression of sFPR1 and Slug, multivariate Cox regression analysis revealed that sFPR1 expression was an independent prognostic factor for CRC patients. Moreover, we found that the expression of slug and β-catenin could be regulated by sFPR1 in SW480 cells, and migration capacity of SW480 cells was suppressed with sFPR1 restoration. In summary, our data suggest that sFRP1, Slug and β-catenin are related to metastasis and prognosis in CRC. sFPR1 could mediate CRC metastasis by regulating the expression of Slug and β-catenin. Combined detection of these factors may be of significant value in predicting the metastasis and prognosis in CRC patients.

Upregulation of miR-543-3p promotes growth and stem cell-like phenotype in bladder cancer by activating the Wnt/β-catenin signaling pathway

The Wnt/β-catenin signaling pathway, which is strictly controlled by multiple negative regulators, has been reported commonly hyper activated and closely related to the progression of bladder cancer. However, how tumor cells override the negative regulatory effects to maintain constitutive activation of Wnt/β-catenin signaling is still unclear. In the current study, we demonstrated that upregulation of miR-543-3p in bladder cancer activated Wnt/β-catenin signaling by directly targeting Wnt inhibitory factor 1 (WIF1) and Dickkopf 1 (DKK1), which are important antagonist molecules of the Wnt/β-catenin pathway. Expression of miR-543-3p was upregulated in both bladder cancer tissues and cells, and positively correlated with high-grade bladder cancer. Furthermore, ectopic overexpression of miR-543-3p promoted proliferation and inhibited apoptosis in bladder cancer cells. Notably, overexpression of miR-543-3p enhanced, while silencing miR-543-3p reduced, stem cell-like phenotype of bladder cancer cells. Therefore, our results suggest that miR-543-3p plays a significant role in promoting proliferation and stem cell-like phenotype in bladder cancer, which might be a potential target for anti-bladder cancer therapy.

Antagonizing canonical Wnt signaling pathway by recombinant human sFRP4 purified from E. coli and its implications in cancer therapy

The Wnt signaling pathway plays a predominant role in aberrant proliferation in myriad of cancers. In non-cancerous cells, Wnts are blocked by the secreted frizzled-related proteins (sFRPs) that are generally downregulated in cancer cells. We have purified and characterized bacterially expressed glutathione S-transferase-tagged SFRP4 from a novel clone generated from human cell origin. Cervical cancer (HeLa) and lung cancer (A549) cells, in which Wnt and associated genes were found to be expressed, were treated with the purified recombinant sFRP4, which revealed a significant dose-dependent cell growth inhibition up to 40 %. The current investigation on functionality of this bacterially produced recombinant sFRP4 in arresting cancer cell proliferation is the first of its kind, where G2/M phase arrest and early apoptosis were evident. Increase in phosphorylated β-catenin in sFRP4 treatment indicated inhibition of Wnt pathway, which was further confirmed by downregulation of pro-proliferative genes, namely cyclin D1, c-myc, and survivin. Functional activity of recombinant sFRP4 was further exploited in co-therapy module with chemotherapeutic drugs to decipher molecular events. Collectively, our study on purified recombinant sFRP4 from bacterial host holds great promise in targeting Wnt signaling for exploring new strategies to combat cancer.

ImmuCo: a database of gene co-expression in immune cells

Current gene co-expression databases and correlation networks do not support cell-specific analysis. Gene co-expression and expression correlation are subtly different phenomena, although both are likely to be functionally significant. Here, we report a new database, ImmuCo (http://immuco.bjmu.edu.cn), which is a cell-specific database that contains information about gene co-expression in immune cells, identifying co-expression and correlation between any two genes. The strength of co-expression of queried genes is indicated by signal values and detection calls, whereas expression correlation and strength are reflected by Pearson correlation coefficients. A scatter plot of the signal values is provided to directly illustrate the extent of co-expression and correlation. In addition, the database allows the analysis of cell-specific gene expression profile across multiple experimental conditions and can generate a list of genes that are highly correlated with the queried genes. Currently, the database covers 18 human cell groups and 10 mouse cell groups, including 20 283 human genes and 20 963 mouse genes. More than 8.6 × 10⁸ and 7.4 × 10⁸ probe set combinations are provided for querying each human and mouse cell group, respectively. Sample applications support the distinctive advantages of the database.