Aberrant methylation of secreted frizzled‐related protein genes in esophageal adenocarcinoma and Barrett's esophagus

Abstract

Hypermethylation of secreted frizzled-related proteins (SFRP) genes frequently occurs with several cancers but has not been studied in esophageal adenocarcinoma or its precursor-Barrett's esophagus. To explore the role of SFRP methylation in the neoplastic progression of Barrett's esophagus and to evaluate methylated SFRP genes as biomarkers for Barrett's esophagus and cancer, methylation of SFRP genes was determined in esophageal adenocarcinomas, Barrett's esophagus and normal epithelia using methylation-specific PCR. Protein expression of SFRP genes was then assessed in these tissues by immunohistochemistry. The mRNA expression of SFRP genes was quantified by real-time reverse-transcription PCR in esophageal adenocarcinoma cell lines with and without demethylation by 5-aza-2 0 deoxycytidine and inhibition of deacetylation by trichostatin A treatment. Hypermethylation of SFRP1, 2, 4 and 5 was detected in 93%, 83%, 73% and 85% of 40 cancers; 81%, 89%, 78% and 73% of 37 Barrett's epithelia; 25%, 64%, 32% and 21% of 28 adjacent normal epithelia from Barrett's patients; and 10%, 67%, 0% and 13% of 30 normal esophagogastric epithelia from healthy individuals, respectively (p < 0.001 for SFRP1, 4 and 5; p < 0.05 for SFRP2). Protein expression of SFRP1, 2 and 4 was downregulated in 87%, 67% and 90% of cancers, and expression correlated inversely with grade and stage of cancers and with grade of dysplasia. Expression of SFRP2 and SFRP4 proteins was lower in cancers with corresponding gene methylation (p < 0.05). Demethylation treatment effectively re-expressed SFRP mRNA in cancer cell lines. Thus, hypermethylation of SFRP genes is a common early event in the evolution of esophageal adenocarcinoma, and methylation of SFRP1, 4 and 5 might serve as biomarkers for Barrett's neoplasia. Aberrant promoter methylation appears to functionally silence SFRP gene expression in esophageal adenocarcinoma. ' 2005 Wiley-Liss, Inc.Key words: DNA methylation; esophageal adenocarcinoma; Barrett's esophagus; secreted frizzed-related protein (SFRP); tumor markerThe incidence of esophageal adenocarcinoma is increasing at an alarming rate in western countries.1 Nearly all such cancers arise from Barrett's esophagus, a metaplastic condition in which intestinal-type epithelium replaces the normal squamous epithelium. 2The molecular mechanisms of this premalignant condition remain incompletely understood. Inactivation of tumor suppressor genes by promoter hypermethylation has been considered as a potentially important mechanism involved in the development of Barrett's esophagus.3 Several tumor suppressor genes, most notably p16, have been found to undergo epigenetic changes in Barrett's esophagus. [3][4][5][6] Aberrant promoter methylation of a new class of tumor suppressor genes, 7 secreted frizzled-related protein (SFRP) genes, has been described in colon and gastric cancers.8 SFRPs are secreted glycoproteins that work as inhibitive modulators of a putative tumorigenic pathway-the Wnt pathway, in which signals are transduced by Wnt ligands t...

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“…In humans, downregulation of Sfrp1, Sfrp2, Sfrp4, and Sfrp5 has been correlated with Barrett's esophagus (Zou et al 2005) a precancerous neoplasia where the esophageal epithelium is transformed into more posterior intestinal fates. Moreover, Sfrps are known to be tumor suppressors that are epigenetically inactivated in many cancers as they progress to aggressive carcinomas (Nojima et al 2007;Nomoto et al 2007).…”

Coincident expression of β-catenin and cyclin D1 in endometrial stromal tumors and related high-grade sarcomas

“…The primer pairs used in this study were the same as those previously described in the literature. 19 Bisulfite-treated human genomic DNA (Clonetech) and CpGenome Universal Methylated DNA (Chemicon, Temecula, CA, USA) were used as positive controls for unmethylation and methylation, respectively.…”

Secreted Frizzled-Related Protein 4 Regulates Two Wnt7a Signaling Pathways and Inhibits Proliferation in Endometrial Cancer Cells

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