Research IndicatorsGraph generated 28 February 2015 using data from PubMed using criteria.
Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic. Tag cloud generated 27 February, 2015 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).
OMIM, Johns Hopkin University
Referenced article focusing on the relationship between phenotype and genotype.
International Cancer Genome Consortium.
Summary of gene and mutations by cancer type from ICGC
Cancer Genome Anatomy Project, NCI
COSMIC, Sanger Institute
Somatic mutation information and related details
Search the Epigenomics database and view relevant gene tracks of samples.
Latest Publications: SFRP4 (cancer-related)
Brebi P, Hoffstetter R, Andana A, et al.Evaluation of ZAR1 and SFRP4 methylation status as potentials biomarkers for diagnosis in cervical cancer: exploratory study phase I.
Biomarkers. 2014; 19(3):181-8 [PubMed
] Related Publications
CONTEXT: Aberrant hypermethylation of promoter region of tumor suppressor genes could be used as cancer biomarkers.
OBJECTIVE: To test methylation status of ZAR1 and SFRP4 promoter regions as potentials biomarkers for diagnosis of preneoplastic and neoplastic lesions of cervix.
MATERIALS AND METHODS: Cytobrush samples were evaluated by Methylation specific PCR (MSP) and quantitative MSP (qMSP).
RESULTS: ZAR1 and SFRP4 methylation frequency increased as the grade of lesion increased and the differences between normal and cervical cancer (CC) are statistically significant (p < 0.0001). qMSP showed higher ZAR1 and SFRP4 methylation levels in cancer than normal epithelia (p < 0.001) and preneoplastics lesions (p < 0.01).
DISCUSSION: qMSP quantify methylation levels and have high sensitivity and specificity.
CONCLUSION: ZAR1 and SFRP4 qMSP could be used as potential biomarker for CC diagnosis.
Al-Shabanah OA, Hafez MM, Hassan ZK, et al.Methylation of SFRPs and APC genes in ovarian cancer infected with high risk human papillomavirus.
Asian Pac J Cancer Prev. 2014; 15(6):2719-25 [PubMed
] Related Publications
BACKGROUND: Secreted frizzled-related protein (SFRP) genes, new tumor suppressor genes, are negative regulators of the Wnt pathway whose alteration is associated with various tumors. In ovarian cancer, SFRPs genes promoter methylation can lead to gene inactivation. This study investigated mechanisms of SFRP and adenomatous polyposis coli (APC) genes silencing in ovarian cancer infected with high risk human papillomavirus.
MATERIALS AND METHODS: DNA was extracted from 200 formalin-fixed paraffin-embedded ovarian cancer and their normal adjacent tissues (NAT) and DNA methylation was detected by methylation specific PCR (MSP). High risk human papillomavirus (HPV) was detected by nested PCR with consensus primers to amplify a broad spectrum of HPV genotypes.
RESULTS: The percentages of SFRP and APC genes with methylation were significantly higher in ovarian cancer tissues infected with high risk HPV compared to NAT. The methylated studied genes were associated with suppression in their gene expression.
CONCLUSION: This finding highlights the possible role of the high risk HPV virus in ovarian carcinogenesis or in facilitating cancer progression by suppression of SFRP and APC genes via DNA methylation.
García-Baquero R, Puerta P, Beltran M, et al.Methylation of tumor suppressor genes in a novel panel predicts clinical outcome in paraffin-embedded bladder tumors.
Tumour Biol. 2014; 35(6):5777-86 [PubMed
] Related Publications
DNA methylation of tumor suppressor genes (TSGs) represents a frequent and early epigenetic event with potential applications for cancer detection and disease evolution. Our aim was to examine the stratification and prognostic biomarker role of the methylation of a novel panel of TSGs in bladder cancer. The methylation status of 18 TSGs was evaluated in bladder cancer cells (n=14) and paraffin-embedded primary bladder tumors (n=61), using a methylation-specific multiplex ligation-dependent probe amplification assay (MS-MLPA). Recurrence, progression, and disease-specific survival were analyzed using univariate and multivariate Cox models. PRDM2, HLTF, ID4, DLC1, BNIP3, H2AFX, CACNA1G, TGIF, and CACNA1A were discovered methylated in bladder cancer. The methylation of RUNX3 (p=0.026), TWIST1 (p=0.009), SFRP4 (p=0.002), and CCND2 (p=0.027) correlated to tumor stage. Univariate analyses indicated prognostic associations for recurrence (DLC1, SFRP5, H2AFX, CACNA1G), progression (DLC1, SFRP5, CACNA1G), disease-specific (PRDM2, DLC1, SFRP5, CACNA1G, and TIMP3), and overall survival (SFRP5 and TIMP3). In multivariate analyses, several TSGs remained as independent prognosticators for recurrence (SFRP5, H2AFX), progression (CACNA1G), and disease-specific survival (SFRP5). Thus, a novel set of TSGs was identified, frequently methylated in bladder cancer cells and tumors. TSG methylation allowed histopathologic and outcome stratification using paraffin-embedded tumors. This is clinically relevant by offering a strategy for the management of patients affected with uroepithelial neoplasias in pathology routine laboratories.
Saito T, Mitomi H, Imamhasan A, et al.Downregulation of sFRP-2 by epigenetic silencing activates the β-catenin/Wnt signaling pathway in esophageal basaloid squamous cell carcinoma.
Virchows Arch. 2014; 464(2):135-43 [PubMed
] Related Publications
Basaloid squamous cell carcinoma (BSCC) of the esophagus is a rare variant of typical squamous cell carcinoma (SCC) associated with poor survival. A characteristic feature is nuclear accumulation of β-catenin, without a mutation of the gene. We studied the methylation status of Wnt antagonist genes, such as secreted frizzled-related protein (sFRP) gene family members, Wnt inhibitory factor-1 (WIF-1), Dickkopf-1 (Dkk-1), and human Dapper protein-1 (HDPR-1), and alterations of the APC, Axin1, and Axin2 genes in 30 cases of esophageal BSCC. β-catenin and sFRP (sFRP-1, sFRP-2, sFRP-4, sFRP-5) protein expression was examined by immunohistochemistry. APC, Axin1, and Axin2 gene mutations were detected in 3, 2, and 2 cases, respectively, and 6 cases (20 %) harbored at least 1 alteration in these genes. Methylation of the sFRP-2 promoter region was observed in all cases, and methylation was frequent in sFRP-1 and sFRP-5, but infrequent in Dkk-1, WIF-1, sFRP-4, and HDPR-1. sFRP-2 expression was almost completely absent in 25 cases (83 %), consistent with the methylation status. Nuclear accumulation of β-catenin was observed in all cases. sFRP-5 expression was associated with a low nuclear β-catenin labeling index. These results show that sFRP-2 is a target gene of hypermethylation in esophageal BSCC and suggest that sFRP-2 might contribute to BSCC tumorigenesis through the Wnt/β-catenin signaling pathway.
Psyrri A, Kotoula V, Fountzilas E, et al.Prognostic significance of the Wnt pathway in squamous cell laryngeal cancer.
Oral Oncol. 2014; 50(4):298-305 [PubMed
] Related Publications
OBJECTIVES: We sought to determine the prognostic significance of the Wnt signaling pathway in operable squamous cell carcinoma of the larynx.
MATERIALS AND METHODS: In an annotated cohort of 289 operable laryngeal cancers we evaluated the prognostic impact of E-cadherin, P-cadherin and β-catenin protein expression with immunohistochemistry, as well as the mRNA expression of 7 key effectors of the Wnt pathway including secreted frizzled-related protein 4 (SFRP4), SNAI2 (SLUG) and WNT5A with qPCR (relative quantification [RQ]).
RESULTS: Using median immunoreactive scores as a pre-defined cut-off, patients whose tumors overexpressed both cytoplasmic E-cadherin and β-catenin experienced longer median OS as compared to those whose tumors overexpressed β-catenin only (median OS 124 vs. 72 months, p=0.0301) and patients whose tumors overexpressed both cytoplasmic and membranous E-cadherin experienced longer DFS as compared to those whose tumors overexpressed cytoplasmic E-cadherin only (median 118 vs. 91 months, p=0.0106). Upon hierarchical clustering of SFRP4, SNAI2 and WNT5A RQ values, profiles including co-expression of all 3 genes but also profiles with under-expression of SNAI2 and WNT5A were associated with worse outcome as compared to profiles not related to the Wnt pathway. In multivariate analysis, clustering was an independent predictor for DFS (p=0.0221) and OS (p=0.0077).
CONCLUSION: We identified gene expression profiles and IHC patterns associated with aberrant Wnt signaling conferring aggressive clinical behavior in operable squamous cell carcinoma of the larynx. Prospective validation of these results will determine whether targeting the Wnt pathway merits investigation in this disease.
Warrier S, Balu SK, Kumar AP, et al.Wnt antagonist, secreted frizzled-related protein 4 (sFRP4), increases chemotherapeutic response of glioma stem-like cells.
Oncol Res. 2013; 21(2):93-102 [PubMed
] Related Publications
Malignant gliomas have a highly tumorigenic subpopulation, termed cancer stem cells (CSCs), that drives tumor formation and proliferation. CSCs possess inherent resistance mechanisms against radiation- and chemotherapy-induced cancer cell death, enabling them to survive and initiate tumor recurrence. We examined the effect of secreted frizzled-related protein 4 (sFRP4), a Wnt signaling antagonist, in chemosensitizing the glioma cell line U138MG and glioma stem cells (GSCs) enriched from U138MG to chemotherapeutics. We found that sFRP4 alone and in combination with either doxorubicin or cisplatin induced apoptosis. Proliferation decreased substantially in GSC-enriched population as measured by MTT and BrdU assays. JC-1 and caspase-3 assays demonstrated that cell death was through the apoptotic pathway. sFRP4 treatment also decreased neurosphere formation and induced neuronal differentiation. Inhibition by sFRP4 was abolished by Wnt3a, indicating that sFRP4 acts through the frizzled receptor. Further indication that sFRP4 acts through the Wnt β-catenin pathway was provided by decrease in the β-catenin protein and decrease in the β-catenin-stimulated gene cyclin D1 upon sFRP4 induction. By real-time PCR, an increase in apoptotic markers Bax and p21, a decrease in pro-proliferative marker CycD1, and a decrease in the GSC marker CD133 were observed. These observations indicate that sFRP4 is able to sensitize glioma cells and stem cells to chemotherapeutics. We thus identified for the first time that sFRP4 could help to destroy cancer stem cells of glioma cell line, which would lead to effective treatment regimen to combat brain tumors.
Fox SA, Richards AK, Kusumah I, et al.Expression profile and function of Wnt signaling mechanisms in malignant mesothelioma cells.
Biochem Biophys Res Commun. 2013; 440(1):82-7 [PubMed
] Related Publications
Malignant mesothelioma (MM) is an uncommon and particularly aggressive cancer associated with asbestos exposure, which currently presents an intractable clinical challenge. Wnt signaling has been reported to play a role in the neoplastic properties of mesothelioma cells but has not been investigated in detail in this cancer. We surveyed expression of Wnts, their receptors, and other key molecules in this pathway in well established in vitro mesothelioma models in comparison with primary mesothelial cultures. We also tested the biological response of MM cell lines to exogenous Wnt and secreted regulators, as well as targeting β-catenin. We detected frequent expression of Wnt3 and Wnt5a, as well as Fzd 2, 4 and 6. The mRNA of Wnt4, Fzd3, sFRP4, APC and axin2 were downregulated in MM relative to mesothelial cells while LEF1 was overexpressed in MM. Functionally, we observed that Wnt3a stimulated MM proliferation while sFRP4 was inhibitory. Furthermore, directly targeting β-catenin expression could sensitise MM cells to cytotoxic drugs. These results provide evidence for altered expression of a number of Wnt/Fzd signaling molecules in MM. Modulation of Wnt signaling in MM may prove a means of targeting proliferation and drug resistance in this cancer.
Goeppert B, Konermann C, Schmidt CR, et al.Global alterations of DNA methylation in cholangiocarcinoma target the Wnt signaling pathway.
Hepatology. 2014; 59(2):544-54 [PubMed
] Related Publications
UNLABELLED: The molecular mechanisms underlying the genesis of cholangiocarcinomas (CCs) are poorly understood. Epigenetic changes such as aberrant hypermethylation and subsequent atypical gene expression are characteristic features of most human cancers. In CC, data regarding global methylation changes are lacking so far. We performed a genome-wide analysis for aberrant promoter methylation in human CCs. We profiled 10 intrahepatic and 8 extrahepatic CCs in comparison to non-neoplastic biliary tissue specimens, using methyl-CpG immunoprecipitation (MCIp) combined with whole-genome CpG island arrays. DNA methylation was confirmed by quantitative mass spectrometric analysis and functional relevance of promoter hypermethylation was shown in demethylation experiments of two CC cell lines using 5-aza-2'deoxycytidine (DAC) treatment. Immunohistochemical staining of tissue microarrays (TMAs) from 223 biliary tract cancers (BTCs) was used to analyze candidate gene expression at the protein level. Differentially methylated, promoter-associated regions were nonrandomly distributed and enriched for genes involved in cancer-related pathways including Wnt, transforming growth factor beta (TGF-β), and PI3K signaling pathways. In CC cell lines, silencing of genes involved in Wnt signaling, such as SOX17, WNT3A, DKK2, SFRP1, SFRP2, and SFRP4 was reversed after DAC administration. Candidate protein SFRP2 was substantially down-regulated in neoplastic tissues of all BTC subtypes as compared to normal tissues. A significant inverse correlation of SFRP2 protein expression and pT status was found in BTC patients.
CONCLUSION: We provide a comprehensive analysis to define the genome-wide methylation landscape of human CC. Several candidate genes of cancer-relevant signaling pathways were identified, and closer analysis of selected Wnt pathway genes confirmed the relevance of this pathway in CC. The presented global methylation data are the basis for future studies on epigenetic changes in cholangiocarcinogenesis.
Piltonen TT, Chen J, Erikson DW, et al.Mesenchymal stem/progenitors and other endometrial cell types from women with polycystic ovary syndrome (PCOS) display inflammatory and oncogenic potential.
J Clin Endocrinol Metab. 2013; 98(9):3765-75 [PubMed
] Free Access to Full Article Related Publications
CONTEXT: Endometrium in polycystic ovary syndrome (PCOS) presents altered gene expression indicating progesterone resistance and predisposing to reduced endometrial receptivity and endometrial cancer.
OBJECTIVE: We hypothesized that an altered endocrine/metabolic environment in PCOS may result in an endometrial "disease phenotype" affecting the gene expression of different endometrial cell populations, including stem cells and their differentiated progeny.
DESIGN AND SETTING: This was a prospective study conducted at an academic medical center.
PATIENTS AND MAIN OUTCOME MEASURES: Proliferative-phase endometrium was obtained from 6 overweight/obese PCOS (National Institutes of Health criteria) and 6 overweight/obese controls. Microarray analysis was performed on fluorescence-activated cell sorting-isolated endometrial epithelial cells (eEPs), endothelial cells, stromal fibroblasts (eSFs), and mesenchymal stem cells (eMSCs). Gene expression data were validated using microfluidic quantitative RT-PCR and immunohistochemistry.
RESULTS: The comparison between eEP(PCOS) and eEP(Ctrl) showed dysregulation of inflammatory genes and genes with oncogenic potential (CCL2, IL-6, ORM1, TNAIFP6, SFRP4, SPARC). eSF(PCOS) and eSF(Ctrl) showed up-regulation of inflammatory genes (C4A/B, CCL2, ICAM1, TNFAIP3). Similarly, in eMSC(PCOS) vs eMSC(Ctrl), the most up-regulated genes were related to inflammation and cancer (IL-8, ICAM1, SPRR3, LCN2). Immunohistochemistry scoring showed increased expression of CCL2 in eEP(PCOS) and eSF(PCOS) compared with eEP(Ctrl) and eSF(Ctrl) and IL-6 in eEP(PCOS) compared with eEP(Ctrl).
CONCLUSIONS: Isolated endometrial cell populations in women with PCOS showed altered gene expression revealing inflammation and prooncogenic changes, independent of body mass index, especially in eEP(PCOS) and eMSC(PCOS), compared with controls. The study reveals an endometrial disease phenotype in women with PCOS with potential negative effects on endometrial function and long-term health.
Páez D, Gerger A, Zhang W, et al.Association of common gene variants in the WNT/β-catenin pathway with colon cancer recurrence.
Pharmacogenomics J. 2014; 14(2):142-50 [PubMed
] Related Publications
Wnt/β-catenin signaling has a central role in the development and progression of most colon cancers (CCs). Germline variants in Wnt/β-catenin pathway genes may result in altered gene function and/or activity, thereby causing inter-individual differences in relation to tumor recurrence capacity and chemoresistance. We investigated germline polymorphisms in a comprehensive panel of Wnt/β-catenin pathway genes to predict time to tumor recurrence (TTR) in patients with stage III and high-risk stage II CC. A total of 234 patients treated with 5-fluorouracil-based chemotherapy were included in this study. Whole-blood samples were analyzed for putative functional germline polymorphisms in SFRP3, SFRP4, DKK2, DKK3, Axin2, APC, TCF7L2, WNT5B, CXXC4, NOTCH2 and GLI1 genes by PCR-based restriction fragment-length polymorphism or direct DNA sequencing. Polymorphisms with statistical significance were validated in an independent study cohort. The minor allele of WNT5B rs2010851 T>G was significantly associated with a shorter TTR (10.7 vs 4.9 years; hazard ratio: 2.48; 95% CI, 0.96-6.38; P=0.04) in high-risk stage II CC patients. This result remained significant in multivariate Cox's regression analysis. This study shows that the WNT5B germline variant rs2010851 was significantly identified as a stage-dependent prognostic marker for CC patients after 5-fluorouracil-based adjuvant therapy.
Huang X, Hao C, Shen X, et al.Differences in the transcriptional profiles of human cumulus cells isolated from MI and MII oocytes of patients with polycystic ovary syndrome.
Reproduction. 2013; 145(6):597-608 [PubMed
] Related Publications
Polycystic ovary syndrome (PCOS) is a common endocrine and metabolic disorder in women. The abnormalities of endocrine and intra-ovarian paracrine interactions may change the microenvironment for oocyte development during the folliculogenesis process and reduce the developmental competence of oocytes in PCOS patients who are suffering from anovulatory infertility and pregnancy loss. In this microenvironment, the cross talk between an oocyte and the surrounding cumulus cells (CCs) is critical for achieving oocyte competence. The aim of our study was to investigate the gene expression profiles of CCs obtained from PCOS patients undergoing IVF cycles in terms of oocyte maturation by using human Genome U133 Plus 2.0 microarrays. A total of 59 genes were differentially expressed in two CC groups. Most of these genes were identified to be involved in one or more of the following pathways: receptor interactions, calcium signaling, metabolism and biosynthesis, focal adhesion, melanogenesis, leukocyte transendothelial migration, Wnt signaling, and type 2 diabetes mellitus. According to the different expression levels in the microarrays and their putative functions, six differentially expressed genes (LHCGR, ANGPTL1, TNIK, GRIN2A, SFRP4, and SOCS3) were selected and analyzed by quantitative RT-PCR (qRT-PCR). The qRT-PCR results were consistent with the microarray data. Moreover, the molecular signatures (LHCGR, TNIK, and SOCS3) were associated with developmental potential from embryo to blastocyst stage and were proposed as biomarkers of embryo viability in PCOS patients. Our results may be clinically important as they offer a new potential strategy for competent oocyte/embryo selection in PCOS patients.
Aberrant Wnt signalling is implicated in numerous human cancers, and understanding the effects of modulation of pathway members may lead to the development of novel therapeutics. Expression of secreted frizzled related protein 4 (SFRP4), an extracellular modulator of the Wnt signalling pathway, is progressively lost in more aggressive ovarian cancer phenotypes. Here we show that recombinant SFRP4 (rSFRP4) treatment of a serous ovarian cancer cell line results in inhibition of β-catenin dependent Wnt signalling as measured by TOP/FOP Wnt reporter assay and decreased transcription of Wnt target genes, Axin2, CyclinD1 and Myc. In addition, rSFRP4 treatment significantly increased the ability of ovarian cancer cells to adhere to collagen and fibronectin, and decreased their ability to migrate across an inflicted wound. We conclude that these changes in cell behaviour may be mediated via mesenchymal to epithelial transition (MET), as rSFRP4 treatment also resulted in increased expression of the epithelial marker E-cadherin, and reduced expression of Vimentin and Twist. Combined, these results indicate that modulation of a single upstream gatekeeper of Wnt signalling can have effects on downstream Wnt signalling and ovarian cancer cell behaviour, as mediated through epithelial to mesenchymal plasticity (EMP). This raises the possibility that SFRP4 may be used both diagnostically and therapeutically in epithelial ovarian cancer.
Saran U, Arfuso F, Zeps N, Dharmarajan ASecreted frizzled-related protein 4 expression is positively associated with responsiveness to cisplatin of ovarian cancer cell lines in vitro and with lower tumour grade in mucinous ovarian cancers.
BMC Cell Biol. 2012; 13:25 [PubMed
] Free Access to Full Article Related Publications
BACKGROUND: Ovarian cancer is one of the most lethal malignancies in women, as it is frequently detected at an advanced stage, and cancers often become refractory to chemotherapy. Evidence suggests that dysregulation of pro-apoptotic genes plays a key role in the onset of chemoresistance. The secreted Frizzled-Related Protein (sFRP) family is pro-apoptotic and also a negative modulator of the Wnt signalling cascade. Studies have demonstrated that the re-expression of sFRPs, in particular sFRP4, is associated with a better prognosis, and that experimentally induced expression results in cell death.
RESULTS: In vitro experimental models determined that sFRP4 was differentially expressed in chemosensitive (A2780) and chemoresistant (A2780 ADR and A2780 Cis) ovarian cell lines, with chemosensitive cells expressing significantly higher levels of sFRP4. Transfection of the chemoresistant cell lines with sFRP4 significantly increased their sensitivity to chemotherapy. Conversely, silencing of sFRP4 expression in the chemosensitive cell line resulted in a corresponding increase in chemoresistance. Comparison of sFRP4 expression in tumour biopsies revealed a positive trend between sFRP4 expression and tumour grade, with mucinous cyst adenocarcinomas exhibiting significantly decreased sFRP4 levels compared to mucinous borderline tumours.
CONCLUSIONS: This study indicates a role for sFRP4 as a predictive marker of chemosensitivity in ovarian cancer and suggests that this pathway may be worth exploiting for novel therapies.
Pérez-Magán E, Campos-Martín Y, Mur P, et al.Genetic alterations associated with progression and recurrence in meningiomas.
J Neuropathol Exp Neurol. 2012; 71(10):882-93 [PubMed
] Related Publications
Meningiomas are the most common primary brain tumors; they arise from the coverings of the brain. Although meningiomas are generally benign, some are more clinically aggressive, as reflected by their histopathological features or by their unexpected recurrence. We hypothesized that recurrent histologically benign meningiomas might have genetic features in common with those showing a more aggressive histology. By comparing gene expression profiles associated with meningioma progression and recurrence in 128 tumor samples (i.e. 83 benign World Health Organization [WHO] Grade I, 37 atypical WHO Grade II, and 8 anaplastic WHO Grade III) from 121 patients, we identified a 49-gene signature of meningioma aggressivity. This signature classified the tumors into 2 groups showing different clinical and pathological behaviors. The signature was composed of genes involved in the cell cycle (TMEM30B, CKS2, and UCHL1) and other pathways previously described as being altered in meningiomas, that is, WNT (SFRP1 and SFRP4) and transforming growth factor-β pathways (LTBP2 and LMO4). Overall, gene downregulation was observed in advanced and recurrent samples versus benign and original ones. We propose that this gene repression may be caused by gene promoter hypermethylation, as in the case of UCHL1 and SFRP1, suggesting that this epigenetic event, together with loss of specific chromosomal regions, may play an important role in meningioma progression and recurrence.
Perry AS, O'Hurley G, Raheem OA, et al.Gene expression and epigenetic discovery screen reveal methylation of SFRP2 in prostate cancer.
Int J Cancer. 2013; 132(8):1771-80 [PubMed
] Related Publications
Aberrant activation of Wnts is common in human cancers, including prostate. Hypermethylation associated transcriptional silencing of Wnt antagonist genes SFRPs (Secreted Frizzled-Related Proteins) is a frequent oncogenic event. The significance of this is not known in prostate cancer. The objectives of our study were to (i) profile Wnt signaling related gene expression and (ii) investigate methylation of Wnt antagonist genes in prostate cancer. Using TaqMan Low Density Arrays, we identified 15 Wnt signaling related genes with significantly altered expression in prostate cancer; the majority of which were upregulated in tumors. Notably, histologically benign tissue from men with prostate cancer appeared more similar to tumor (r = 0.76) than to benign prostatic hyperplasia (BPH; r = 0.57, p < 0.001). Overall, the expression profile was highly similar between tumors of high (≥ 7) and low (≤ 6) Gleason scores. Pharmacological demethylation of PC-3 cells with 5-Aza-CdR reactivated 39 genes (≥ 2-fold); 40% of which inhibit Wnt signaling. Methylation frequencies in prostate cancer were 10% (2/20) (SFRP1), 64.86% (48/74) (SFRP2), 0% (0/20) (SFRP4) and 60% (12/20) (SFRP5). SFRP2 methylation was detected at significantly lower frequencies in high-grade prostatic intraepithelial neoplasia (HGPIN; 30%, (6/20), p = 0.0096), tumor adjacent benign areas (8.82%, (7/69), p < 0.0001) and BPH (11.43% (4/35), p < 0.0001). The quantitative level of SFRP2 methylation (normalized index of methylation) was also significantly higher in tumors (116) than in the other samples (HGPIN = 7.45, HB = 0.47, and BPH = 0.12). We show that SFRP2 hypermethylation is a common event in prostate cancer. SFRP2 methylation in combination with other epigenetic markers may be a useful biomarker of prostate cancer.
BACKGROUND: The Wnt/β-catenin signalling is aberrantly activated in primary B cell chronic lymphocytic leukaemia (CLL). Epigenetic silencing of pathway inhibitor genes may be a mechanism for its activation. In this study, we investigated systematically and quantitatively the methylation status of 12 Wnt/β-catenin pathway inhibitor genes - CDH1, DACT1, DKK1, DKK2, DKK3, DKK4, SFRP1, SFRP2, SFRP3, SFRP4, SFRP5 and WIF1 - in the cell lines EHEB and MEC-1 as well as patient samples.
METHODS: Quantification of DNA methylation was performed by means of bisulphite pyrosequencing and confirmed by bisulphite Sanger sequencing. Gene expression was analysed by qPCR using GAPDH as internal control. E-cadherin and β-catenin protein quantification was carried out by microsphere-based immunoassays. Methylation differences observed between the patient and control groups were tested using generalised least squares models.
RESULTS: For 10 genes, a higher methylation level was observed in tumour material. Only DKK4 exhibited similarly high methylation levels in both tumour and normal specimens, while DACT1 was always essentially unmethylated. However, also for these inhibitors, treatment of cells with the demethylating agent 5-aza-2´-deoxycytidine resulted in an induction of their expression, as shown by quantitative PCR, suggesting an indirect epigenetic control of activity. While the degree of demethylation and its transcriptional consequences differed between the genes, there was an overall high correlation of demethylation and increased activity. Protein expression studies revealed that no constitutive Wnt/β-catenin signalling occurred in the cell lines, which is in discrepancy with results from primary CLL. However, treatment with 5-aza-2´-deoxycytidine caused accumulation of β-catenin. Simultaneously, E-cadherin expression was strongly induced, leading to the formation of a complex with β-catenin and thus demonstrating its epigenetically regulated inhibition effect.
CONCLUSIONS: The results suggest an epigenetic silencing mechanism of the Wnt/β-catenin pathway inhibitor genes in CLL. Hypermethylation and silencing of functionally related genes may not be completely stochastic but result from the tumour epigenome reprogramming orchestrated by Polycomb-group repressive complexes. The data are of interest in the context of epigenetic-based therapy.
BACKGROUND: Activation of the Wnt signaling pathway is implicated in aberrant cellular proliferation in various cancers. In 40% of endometrioid ovarian cancers, constitutive activation of the pathway is due to oncogenic mutations in β-catenin or other inactivating mutations in key negative regulators. Secreted frizzled-related protein 4 (SFRP4) has been proposed to have inhibitory activity through binding and sequestering Wnt ligands.
METHODOLOGY/PRINCIPAL FINDINGS: We performed RT-qPCR and Western-blotting in primary cultures and ovarian cell lines for SFRP4 and its key downstream regulators activated β-catenin, β-catenin and GSK3β. SFRP4 was then examined by immunohistochemistry in a cohort of 721 patients and due to its proposed secretory function, in plasma, presenting the first ELISA for SFRP4. SFRP4 was most highly expressed in tubal epithelium and decreased with malignant transformation, both on RNA and on protein level, where it was even more profound in the membrane fraction (p<0.0001). SFRP4 was expressed on the protein level in all histotypes of ovarian cancer but was decreased from borderline tumors to cancers and with loss of cellular differentiation. Loss of membrane expression was an independent predictor of poor survival in ovarian cancer patients (p = 0.02 unadjusted; p = 0.089 adjusted), which increased the risk of a patient to die from this disease by the factor 1.8.
CONCLUSIONS/SIGNIFICANCE: Our results support a role for SFRP4 as a tumor suppressor gene in ovarian cancers via inhibition of the Wnt signaling pathway. This has not only predictive implications but could also facilitate a therapeutic role using epigenetic targets.
Shen JZ, Xu CB, Fu HY, et al.Methylation of secreted frizzled related protein gene in acute leukemia patients in China.
Asian Pac J Cancer Prev. 2011; 12(10):2617-21 [PubMed
] Related Publications
BACKGROUND: DNA methylation of CpG islands within the promoters of specific genes may play roles in tumor initiation and progression. It has been suggested such events may serve as critical check points.
METHODS: The present study analyzed the methylation status of CpG islands within the promoters of secreted frizzled-related proteins (SFRPs) in 87 acute leukemia (AL) patients, 20 normal controls, and four AL cell lines. 5-aza-2'- deoxycytidine (5-Aza-CdR), an inhibitor of DNA methylation, was employed to determine its effect on SFRP expression.
RESULT: Methylation of at least one SFRP promoter was observed in 69% of the AL patients analyzed. In addition, methylation of all four SFRP promoters was observed in Molt-4, Jurkat, HL60 and NB4 cells. In Jurkat cells, methylation levels of four SFRP promoters decreased in a dose-dependent manner upon treatment with 5-Aza-CdR, which coincided with increased mRNA expression. With increasing 5-Aza-CdR concentrations, the expression of DNA methyltransferases, DNMT3A and DNMT3B, significantly decreased in a dose-dependent manner.
CONCLUSION: The present study demonstrated that SFRP gene methylation may be involved in AL progression, with a possible epigenetic mechanism influencing Wnt signaling.
BACKGROUND: Aberrant activation of Wnt signalling through hypermethylation of Wnt inhibitor genes is involved in several human malignancies, including acute myeloid leukaemia (AML). It remains unclear whether hypermethylation of Wnt inhibitors is associated with molecular gene mutations in the development of AML.
METHODS: We investigated the association of the promoter hypermethylation of six Wnt inhibitors (Wif-1, SFRP1, SFRR2, SFRP4, SFRP5, and DKK1) with gene aberrations in the leukaemogenesis of 269 AML patients.
RESULTS: In total, 166 patients (61.7%) had hypermethylation of at least one Wnt inhibitor. The majority (68.5%) of patients with Wnt inhibitor hypermethylation had concurrent Class II gene mutations that affect transcription factors or cofactors. There was a close association of Wif-1 hypermethylation with t(15;17) (P=0.0005) and CEBPA mutation (P<0.0001), DKK1 hypermethylation with t(8;21) (P<0.0001) and ASXL1 mutation (P=0.0078), SFRP-1 hypermethylation with t(8;21) (P<0.0001), SFRP-2 hypermethylation with AML1/RUNX1 mutation (P=0.0012), and SFRP-5 hypermethylation with MLL/PTD (P=0.0505). On the other side, hypermethylation of Wnt inhibitors was always negatively associated with NPM1 mutation and FLT3/ITD.
CONCLUSION: There was distinct association between hypermethylation of individual Wnt inhibitors and specific gene aberrations, especially Class II mutations. The Wnt inhibitor hypermethylation might interact with genetic alterations in the leukaemogenesis.
Park SY, Kwon HJ, Choi Y, et al.Distinct patterns of promoter CpG island methylation of breast cancer subtypes are associated with stem cell phenotypes.
Mod Pathol. 2012; 25(2):185-96 [PubMed
] Related Publications
Although DNA methylation profiles in breast cancer have been connected to breast cancer molecular subtype, there have been no studies of the association of DNA methylation with stem cell phenotype. This study was designed to evaluate the promoter CpG island methylation of 15 genes in relation to breast cancer subtype, and to investigate whether the patterns of CpG island methylation in each subtype are associated with their cancer stem cell phenotype represented by CD44+/CD24- and ALDH1 expression. We performed MethyLight analysis of the methylation status of 15 promoter CpG island loci involved in breast cancer progression (APC, DLEC1, GRIN2B, GSTP1, HOXA1, HOXA10, IGF2, MT1G, RARB, RASSF1A, RUNX3, SCGB3A1, SFRP1, SFRP4, and TMEFF2) and determined cancer stem cell phenotype by CD44/CD24 and ALDH1 immunohistochemistry in 36 luminal A, 33 luminal B, 30 luminal-HER2, 40 HER2 enriched, and 40 basal-like subtypes of breast cancer. The number of CpG island loci methylated differed significantly between subtypes, and was highest in the luminal-HER2 subtype and lowest in the basal-like subtype. Methylation frequencies and levels in 12 of the 15 genes differed significantly between subtypes, and the basal-like subtype had significantly lower methylation frequencies and levels in nine of the genes than the other subtypes. CD44+/CD24- and ALDH1+ putative stem cell populations were most enriched in the basal-like subtype. Methylation of promoter CpG islands was significantly lower in CD44+/CD24-cell (+) tumors than in CD44+/CD24-cell (-) tumors, even within the basal-like subtype. ALDH1 (+) tumors were also less methylated than ALDH1 (-) tumors. Our findings showed that promoter CpG island methylation was different in relation to breast cancer subtype and stem cell phenotype of tumor, suggesting that breast cancers have distinct patterns of CpG island methylation according to molecular subtypes and these are associated with different stem cell phenotypes of the tumor.
Cheng CK, Li L, Cheng SH, et al.Secreted-frizzled related protein 1 is a transcriptional repression target of the t(8;21) fusion protein in acute myeloid leukemia.
Blood. 2011; 118(25):6638-48 [PubMed
] Related Publications
Secreted-frizzled related proteins (SFRPs) are modulators of the Wnt signaling pathway that is closely involved in normal and malignant hematopoiesis. Epigenetic deregulation of Wnt modulators leading to aberrant signaling has been reported in adult patients with acute myeloid leukemia (AML), but its occurrence in childhood patients with AML and the role of individual modulators are unclear. In this study, we examined SFRP1, SFRP2, SFRP4, and SFRP5 promoter methylation in 83 patients with AML (59 children and 24 adults) and found preferential SFRP1 methylation and mRNA down-regulation in the prognostically favorable subgroup of AML with t(8;21) translocation. Among the 4 genes, SFRP1 methylation independently predicted prolonged event-free and relapse-free survivals in childhood patients with nonacute promyelocytic leukemia with nonadverse cytogenetics. Mechanistically, we further demonstrated that RUNX1-ETO, the t(8;21) fusion product, specifically bound the SFRP1 promoter and repressed its transcription via a consensus RUNX binding site. In t(8;21)-leukemia cells, SFRP1 selectively inhibited canonical Wnt signaling and cellular proliferation that were associated with concomitant down-regulation of Wnt/β-catenin target genes, including CCND1 and MYC. Taken together, we identified SFRP1 as a transcriptional repression target of the t(8;21) fusion protein and demonstrated a novel mechanism of Wnt activation in a specific subtype of AML.
BACKGROUND: DNA methylation has been widely used in classification, early diagnosis, therapy and prediction of metastasis as well as recurrence of cervical cancer. DNMT methyltransferase 1 (DNMT1), which plays a significant role in maintaining DNA methylation status and regulating the expression of tumor suppressor genes. The aim of this research was to investigate the relationship between DNMT1 and abnormal methylation of tumor suppressor genes and malignant phenotype in cervical cancer.
METHODS: Levels of DNMT1 mRNA and protein were detected using qPCR and Western blot, respectively. Cell proliferation was analyzed by MTT and apoptosis was performed by Annexin V-FITC/PI double staining flow cytometry, respectively. MeDIP-qPCR and qPCR were performed to measure demethylation status and mRNA re-expression level of 7 tumor-suppressor genes (CCNA1, CHFR, FHIT, PAX1, PTEN, SFRP4, TSLC1) in Hela and Siha cells after silencing DNMT1.
RESULTS: The average expression levels of DNMT1 mRNA and protein in Hela and Siha cells were decreased significantly compared with control group. The flow cytometry and MTT results showed that Hela and Siha cells apoptosis rates and cell viabilities were 19.4 ± 2.90%, 25.7 ± 3.92% as well as 86.7 ± 3.12%, 84.16 ± 2.67% respectively 48 h after transfection (P < 0.01). Furthermore, the promoter methylation of five tumor suppressor genes was decreased with the increased mRNA expression after silencing DNMT1, whereas there were no significant changes in PTEN and FHIT genes in Hela cells, and CHFR and FHIT genes in Siha cells.
CONCLUSIONS: Our experimental results demonstrate that methylation status of DNMT1 can influence several important tumor suppressor genes activity in cervical tumorigenesis and may have the potential to become an effective target for treatment of cervical cancer.
van der Meide WF, Snellenberg S, Meijer CJ, et al.Promoter methylation analysis of WNT/β-catenin signaling pathway regulators to detect adenocarcinoma or its precursor lesion of the cervix.
Gynecol Oncol. 2011; 123(1):116-22 [PubMed
] Related Publications
OBJECTIVE: Cervical adenocarcinoma (AdCA) and adenocarcinoma in situ (ACIS) are frequently missed in cytology-based screening programs. Testing for high-risk human papillomavirus (hrHPV) improves their detection, but novel ACIS/AdCA specific biomarkers are needed to increase specificity for these lesions. Novel markers may be deduced from the WNT/β-catenin signaling pathway, which is aberrantly activated during cervical carcinogenesis.
METHODS: Promoter methylation of nine WNT-antagonists (APC, AXIN2, DKK3, SFRP2, SFRP4, SFRP5, SOX17, WIF1 and WNT5A) was evaluated by methylation-specific PCR (MSP) on a small series of cervical tissue specimens, including AdCA and SCC. To estimate the diagnostic potential of the genes most frequently methylated in AdCA an extended series of ACIS, AdCA, CIN3, SCC, and normal cervical tissue specimens (n=131) as well as 49 hrHPV-positive scrapings were analyzed by quantitative MSP (qMSP).
RESULTS: The frequency of DKK3 and SFRP2 methylation was significantly higher in AdCA compared to SCC, i.e. 82% vs. 18% (p<0.01) and 84% vs. 39% (p<0.01), respectively, while SOX17 methylation frequency was significantly higher in SCC than AdCA, i.e. 89% vs. 62% (p<0.05). Methylation of WIF1 was common in both AdCA (71%) and SCC (54%). Methylation frequencies ranged from 4% to 55% in precursor lesions and from 0% to 5% in normal biopsies. When tested on HPV-positive cervical scrapings, qMSP of the best ACIS/AdCA discriminator genes, i.e. DKK3 and SFRP2, detected all women with underlying ACIS/AdCA, compared to 3% of controls.
CONCLUSIONS: DKK3 and SFRP2 promoter methylation is highly indicative for the presence of ACIS/AdCA, thereby providing promising triage markers for HPV-positive women at risk of ACIS/AdCA.
Di Domenico M, Santoro A, Ricciardi C, et al.Epigenetic fingerprint in endometrial carcinogenesis: the hypothesis of a uterine field cancerization.
Cancer Biol Ther. 2011; 12(5):447-57 [PubMed
] Related Publications
Transcriptional silencing by CpG island hypermethylation plays a critical role in endometrial carcinogenesis. In a collection of benign, premalignant and malignant endometrial lesions, a methylation profile of a complete gene panel, such steroid receptors (ERα, PR), DNA mismatch repair (hMLH1), tumor-suppressor genes (CDKN2A/P16 and CDH1/E-CADHERIN) and WNT pathway inhibitors (SFRP1, SFRP2, SFRP4, SFRP5) was investigated in order to demonstrate their pathogenetic role in endometrial lesions. Our results indicate that gene hypermethylation may be an early event in endometrial endometrioid tumorigenesis. Particularly, ERα, PR, hMLH1, CDKN2A/P16, SFRP1, SFRP2 and SFRP5 revealed a promoter methylation status in endometrioid carcinoma, whereas SFRP4 showed demethylation in cancer. P53 immunostaining showed weak-focal protein expression level both in hyperplasic lesions and in endometrioid cancer. Non-endometrioid cancers showed very low levels of epigenetic methylations, but strong P53 protein positivity. Fisher exact test revealed a statistically significant association between hMLH1, CDKN2A/P16 and SFRP1 genes methylation and endometrioid carcinomas and between hMLH1 gene methylation and peritumoral endometrium (p < 0.05). Our data confirm that the methylation profile of the peritumoral endometrium is different from the altered molecular background of benign endometrial polyps and hyperplasias. Therefore, our findings suggest that the methylation of hMLH1, CDKN2A/P16 and SFRP1 may clearly distinguish between benign and malignant lesions. Finally, this study assessed that the use of an epigenetic fingerprint may improve the current diagnostic tools for a better clinical management of endometrial lesions.
Froeling FE, Feig C, Chelala C, et al.Retinoic acid-induced pancreatic stellate cell quiescence reduces paracrine Wnt-β-catenin signaling to slow tumor progression.
Gastroenterology. 2011; 141(4):1486-97, 1497.e1-14 [PubMed
] Related Publications
BACKGROUND & AIMS: Patients with pancreatic ductal adenocarcinoma are deficient in vitamin A, resulting in activation of pancreatic stellate cells (PSCs). We investigated whether restoration of retinol to PSCs restores their quiescence and affects adjacent cancer cells.
METHODS: PSCs and cancer cell lines (AsPc1 and Capan1) were exposed to doses and isoforms of retinoic acid (RA) in 2-dimensional and 3-dimensional culture conditions (physiomimetic organotypic culture). The effects of all-trans retinoic acid (ATRA) were studied in LSL-KrasG12D/+;LSL-Trp53R172H/+;Pdx-1-Cre mice, a model of human pancreatic ductal adenocarcinoma.
RESULTS: After incubation with ATRA, PSCs were quiescent and had altered expression of genes that regulate proliferation, morphology, and motility; genes that encode cytoskeletal proteins and cytokines; and genes that control other functions, irrespective of culture conditions or dosage. In the organotypic model, and in mice, ATRA induced quiescence of PSCs and thereby reduced cancer cell proliferation and translocation of β-catenin to the nucleus, increased cancer cell apoptosis, and altered tumor morphology. ATRA reduced the motility of PSCs, so these cells created a "wall" at the junction between the tumor and the matrix that prevented cancer cell invasion. Restoring secreted frizzled-related protein 4 (sFRP4) secretion to quiescent PSCs reduced Wnt-β-catenin signaling in cancer cells and their invasive ability. Human primary and metastatic pancreatic tumor tissues stained strongly for cancer cell nuclear β-catenin but had low levels of sFRP4 (in cancer cells and PSCs).
CONCLUSIONS: RA induces quiescence and reduces motility of PSCs, leading to reduced proliferation and increased apoptosis of surrounding pancreatic cancer cells. RA isoforms might be developed as therapeutic reagents for pancreatic cancer.
The role of DNA methylation of CpG islands in parathyroid tumorigenesis has not been analyzed in an unbiased, systematic fashion. DNA was isolated from normal and pathologic parathyroid tissues, bisulphite modified and analyzed using the Infinium HumanMethylation27 BeadChip. Distinct hierarchical clustering of genes with altered DNA methylation profiles in normal and pathologic parathyroid tissue was evident. Comparing normal parathyroid tissue with parathyroid adenomas, 367 genes were significantly altered, while 175 genes significantly differed when comparing parathyroid carcinomas and normal parathyroid tissues. A comparison between parathyroid adenomas and parathyroid carcinomas identified 263 genes with significantly distinct methylation levels. Results were confirmed for certain genes in a validation cohort of 40 parathyroid adenomas by methylation-specific PCR. Genes of known or putative importance in the development of parathyroid tumors showed significant and frequent hypermethylation. DNA hypermethylation of CDKN2B, CDKN2A, WT1, SFRP1, SFRP2, and SFRP4 was associated with reduced gene expression in both benign and malignant parathyroid tumors. Treatment with 5-aza-2'-deoxycytidine of primary cell cultures restores expression of hypermethylated genes in benign and malignant parathyroid tumors. In conclusion, the unbiased, genome-wide study of the parathyroid tumor DNA methylome identified a number of genes with altered DNA methylation patterns of putative importance to benign and malignant parathyroid tumorigenesis.
Guo Y, Guo W, Chen Z, et al.Hypermethylation and aberrant expression of Wnt-antagonist family genes in gastric cardia adenocarcinoma.
Neoplasma. 2011; 58(2):110-7 [PubMed
] Related Publications
The canonical Wnt signalling pathway plays a key role during embryogenesis and pathogenesis of various types of tumors. Recently, several studies have shown that the promoter hypermethylation of Wnt-antagonist genes, including sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1 and Dkk-3, have been certified to contribute to the tumorigenesis of several cancers. The aim of this study was to investigate the promoter methylation of Wnt-antagonist genes in gastric cardia adenocarcinoma (GCA) and corresponding adjacent non-cancerous tissues, and to establish the possible relationship between DNA methylation status and the pathogenesis of GCA. MSP, RT-PCR methods were applied respectively to examine the CpG methylation of the Wnt-antagonist genes and its mRNA expression in tumors and corresponding non-cancerous tissues, and immunohistochemistry method was used to determine protein expression of β-catenin(the key factor of the Wnt signalling pathway) and cyclin D1(the target gene of this pathway). The frequency of promoter methylation of sFRP-1, sFRP-2, sFRP-4, sFRP-5, Wif-1 and Dkk-3 genes in GCA tumor tissues were 78.7%(74/94), 76.6%(72/94), 70.2%(66/94), 77.1%(73/94), 61.7%(58/94) and 21.3%(20/94), respectively, which were significantly higher than those in adjacent non-cancerous tissues. Furthermore, the frequencies of silenced mRNA expression of these six genes in GCA tumor tissues were significantly higher than those in adjacent non-cancerous tissues. Methylation levels of these six genes were all correlated with loss of mRNA expression. The ectopic expression of β-catenin and cyclin D1 was significantly more frequent in GCA tumor tissues than that in adjacent non-cancerous tissues and correlated with each Wnt-antagonist genes hypermethylation status. Epigenetic silencing of Wnt-antagonist genes expression by promoter hypermethylation may play an important role in gastric cardia adenocarcinoma.
Park SY, Kwon HJ, Lee HE, et al.Promoter CpG island hypermethylation during breast cancer progression.
Virchows Arch. 2011; 458(1):73-84 [PubMed
] Related Publications
This study was designed to evaluate the changes in promoter CpG islands hypermethylation during breast cancer progression from pre-invasive lesions [flat epithelial atypia (FEA), atypical ductal hyperplasia (ADH), and ductal carcinoma in situ (DCIS)] to invasive ductal carcinoma (IDC). We performed MethyLight analysis for the methylation status of 57 promoter CpG island loci in 20 IDCs and their paired normal breast tissues. After selecting 15 CpG island loci showing breast cancer-specific DNA methylation, another set of normal breast tissue (n = 10), ADH/FEA (n = 30), DCIS (n = 35), and IDC (n = 30) of the breast were analyzed for these loci. We found six new methylation markers of breast cancer, namely DLEC1, GRIN2B, HOXA1, MT1G, SFRP4, and TMEFF2, in addition to APC, GSTP1, HOXA10, IGF2, RARB, RASSF1A, RUNX3, SCGB3A1 (HIN-1), and SFRP1. The number of methylated genes increased stepwise from normal breast to ADH/FEA and DCIS, while IDC did not differ from DCIS. Methylation levels and frequencies of APC, DLEC1, HOXA1, and RASSF1A promoter CpG islands were significantly higher in ADH/FEA than in normal breast tissue. GRIN2B, GSTP1, HOXA1, RARB, RUNX3, SFRP1, and TMEFF2 showed higher methylation levels and frequencies in DCIS than in ADH/FEA. DICS and IDC did not differ in the methylation levels or frequencies for most CpG island loci except SFRP1 and HOXA10. Our findings showed that promoter CpG island methylation changed significantly in pre-invasive lesions, and was similar in IDC and DCIS, suggesting that CpG island methylation of tumor-related genes is an early event in breast cancer progression.
Assessment of estrogen receptor (ER) expression by immunohistochemistry has yielded inconsistent results as a prognostic indicator in ovarian carcinoma. In breast and endometrial carcinomas, panels of estrogen-induced genes have shown improved prognostic capability over the use of ER immunohistochemistry alone. For both breast and endometrial cancers, overexpression of estrogen-induced genes is associated with better prognosis. We hypothesized that analysis of a panel of estrogen-induced genes can predict the outcome in ovarian carcinoma and potentially differentiate between tumors of varying hormonal responsiveness. From a cohort of 219 women undergoing ovarian cancer surgery from 2004 to 2007, 83 patients were selected for inclusion. All patients had advanced stage ovarian/primary peritoneal high-grade serous carcinoma and underwent primary surgical debulking, followed by adjuvant treatment with platinum and taxane agents. The expression of ERα and six genes known to be induced by estrogen in the female reproductive tract (namely EIG121, sFRP1, sFRP4, RALDH2, PR, and IGF-1) was measured using quantitative RT-PCR. Unsupervised cluster analyses were used to categorize patients as high or low gene expressors. Gene expression results were then compared with those for ER immunohistochemistry. Clusters were compared using χ(2) analyses, and Cox proportional hazards models were used to evaluate survival outcomes. The median follow-up time was 38.7 months (range: 1-68). A cluster defined by EIG121 and ERα segregated tumors into distinct groups of high and low gene expressors. Shorter overall survival (OS) was associated with high gene expression (HR 2.84 (1.11-7.30), P=0.03), even after adjustment for other covariates. No difference in ER immunohistochemistry expression was noted between gene clusters. In contrast to other hormonally driven cancers, high expression of ERα and the estrogen-induced gene EIG121 predicts shorter OS in patients with high-grade serous ovarian carcinoma. Such a biomarker panel may potentially be used to guide management with estrogen antagonists in this patient population.
BACKGROUND: Limited information is available regarding mechanisms by which miRNAs contribute to pulmonary carcinogenesis. The present study was undertaken to examine expression and function of miRNAs induced by cigarette smoke condensate (CSC) in normal human respiratory epithelia and lung cancer cells.
METHODOLOGY: Micro-array and quantitative RT-PCR (qRT-PCR) techniques were used to assess miRNA and host gene expression in cultured cells, and surgical specimens. Software-guided analysis, RNA cross-link immunoprecipitation (CLIP), 3' UTR luciferase reporter assays, qRT-PCR, focused super-arrays and western blot techniques were used to identify and confirm targets of miR-31. Chromatin immunoprecipitation (ChIP) techniques were used to evaluate histone marks and transcription factors within the LOC554202 promoter. Cell count and xenograft experiments were used to assess effects of miR-31 on proliferation and tumorigenicity of lung cancer cells.
RESULTS: CSC significantly increased miR-31 expression and activated LOC554202 in normal respiratory epithelia and lung cancer cells; miR-31 and LOC554202 expression persisted following discontinuation of CSC exposure. miR-31 and LOC554202 expression levels were significantly elevated in lung cancer specimens relative to adjacent normal lung tissues. CLIP and reporter assays demonstrated direct interaction of miR-31 with Dickkopf-1 (Dkk-1) and DACT-3. Over-expression of miR-31 markedly diminished Dkk-1 and DACT3 expression levels in normal respiratory epithelia and lung cancer cells. Knock-down of miR-31 increased Dkk-1 and DACT3 levels, and abrogated CSC-mediated decreases in Dkk-1 and DACT-3 expression. Furthermore, over-expression of miR-31 diminished SFRP1, SFRP4, and WIF-1, and increased Wnt-5a expression. CSC increased H3K4Me3, H3K9/14Ac and C/EBP-β levels within the LOC554202 promoter. Knock-down of C/EBP-β abrogated CSC-mediated activation of LOC554202. Over-expression of miR-31 significantly enhanced proliferation and tumorigenicity of lung cancer cells; knock-down of miR-31 inhibited growth of these cells.
CONCLUSIONS: Cigarette smoke induces expression of miR-31 targeting several antagonists of cancer stem cell signaling in normal respiratory epithelia and lung cancer cells. miR-31 functions as an oncomir during human pulmonary carcinogenesis.