WIF1 is a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix

Abstract

Aberrant activation of the Wnt/b-catenin signaling axis is a prominent oncogenic mechanism in numerous cancers including cervical cancer. Wnt inhibitory factor-1 (WIF1) is a secreted protein that binds Wnt and antagonizes Wnt activity. While the WIF1 gene is characterized as a target for epigenetic silencing in some tumor types, WIF1 expression has not been examined in human cervical tissue and cervical cancer. Here, we show that WIF1 is unmethylated and its gene product is expressed in normal cervical epithelium and some cultured cervical tumor lines. In contrast, several cervical cancer lines contained dense CpG methylation within the WIF1 gene, and expression of both WIF1 transcript and protein was restored by culturing cells in the presence of the global DNA demethylating agent 5-aza-2#-deoxycytidine. Using single-molecule MAPit methylation footprinting, we observed differences in chromatin structure within the WIF1 promoter region between cell lines that express and those that do not express WIF1, consistent with transcriptional activity and repression, respectively. The WIF1 promoter was aberrantly methylated in $60% (10 of 17) high-grade highly undifferentiated squamous cell cervical tumors examined, whereas paired normal tissue showed significantly lower levels of CpG methylation. WIF1 protein was not detectable by immunohistochemistry in tumors with quantitatively high levels of WIF1 methylation. Of note, WIF1 protein was not detectable in two of the seven unmethylated cervical tumors examined, suggesting other mechanisms may contribute WIF1 repression. Our findings establish the WIF1 gene as a frequent target for epigenetic silencing in squamous cell carcinoma of the cervix. Background

Preferential epigenetic programming of estrogen response after in utero xenoestrogen (bisphenol‐A) exposure

“…Several genes that contribute to extracellular matrix remodeling, including Mmp10, Mmp3, Fbln, Krt7, and Muc1, can contribute to increased tumor invasion. Aberration to cell cycle regulators, such as the S100s, can cause unchecked growth, and changes to the regulation of cell signaling components Ret, Stat5a, Fzd10, Cxcl1, and Wif1 can lead to uncontrolled growth and differentiation (24,(34)(35)(36)(37). The abnormal response of these genes to E2 stimulation as a result of BPA treatment in utero is a particularly interesting link to the development of estrogen-sensitive cancers.…”

DNA methylation and nucleosome occupancy regulate the cancer germline antigen geneMAGEA11

“…Highly similar footprints, potentially related to binding of the TIC, have been observed by others. [57][58][59] This Life Technologies). The following primers were used: Outer PCR: 5'-GTGCTCACCT GGAGTCCAAA-3', Inner PCR: 5'-TTCTTCCTCT TGATGCTGGC-3'.…”

Rapid Deamination of Cyclobutane Pyrimidine Dimer Photoproducts at TCG Sites in a Translationally and Rotationally Positioned Nucleosome in Vivo

“…Because bisulfite sequencing is used, it also reports on the methylation status of CpG sites. Unlike hydroxyl radical footprinting, which produces an ensemble average of footprints, the MAPit methylation protection procedure can produce methylation footprints for individual protein and nucleosome arrangements and has been extensively used to study promoters and chromatin structure (35)(36)(37). In this procedure, nuclei are treated with M.CviPI methyltransferase, which methylates the cytosines of all accessible NGCN sites except for those that are blocked by nucleosomes and/or DNA-binding proteins.…”