Aberrant methylation of the Wnt antagonist SFRP1 in breast cancer is associated with unfavourable prognosis

Abstract

The canonical Wnt signalling pathway plays a key role during embryogenesis and defects in this pathway have been implicated in the pathogenesis of various types of tumours, including breast cancer. The gene for secreted frizzled-related protein 1 (SFRP1) encodes a soluble Wnt antagonist and is located in a chromosomal region (8p22-p12) that is often deleted in breast cancer. In colon, lung, bladder and ovarian cancer SFRP1 expression is frequently inactivated by promoter methylation. We have previously shown that loss of SFRP1 protein expression is a common event in breast tumours that is associated with poor overall survival in patients with early breast cancer. To investigate the cause of SFRP1 loss in breast cancer, we performed mutation, methylation and expression analysis in human primary breast tumours and breast cell lines. No SFRP1 gene mutations were detected. However, promoter methylation of SFRP1 was frequently observed in both primary breast cancer (61%, n ¼ 130) and cell lines analysed by methylation-specific polymerase chain reaction (MSP). We found a tight correlation (Po0.001) between methylation and loss of SFRP1 expression in primary breast cancer tissue. SFRP1 expression was restored after treatment of tumour cell lines with the demethylating agent 5-aza-2 0 -deoxycytidine. Most interestingly, SFRP1 promoter methylation was an independent factor for adverse patient survival in Kaplan-Meier analysis. Our results indicate that promoter hypermethylation is the predominant mechanism of SFRP1 gene silencing in human breast cancer and that SFRP1 gene inactivation in breast cancer is associated with unfavourable prognosis.

Frequent epigenetic inactivation of Wnt antagonist genes in breast cancer

“…In primary breast tumours, methylation frequencies of SFRP1, SFRP2, SFRP5 and DKK1 were 40, 77, 71 and 19%, respectively. Although the frequency of SFRP1 methylation in our samples was somewhat lower than those reported by Lo et al (2006) and Veeck et al (2006), we also found that a substantial number of breast tumours harbour SFRP1 methylation. In addition, we found that SFRP2 and SFRP5 are methylated in both cultured breast cancer cells and primary breast cancers at quite high frequencies.…”

“…Using immunohistochemical analysis, Klopocki et al (2004) found that expression of SFRP1 protein was absent in 46% of invasive breast tumours and in 43% of carcinoma in situ. In addition, two groups recently reported frequent SFRP1 methylation in primary breast tumours (Lo et al, 2006;Veeck et al, 2006), and Bafico et al (2004) clearly demonstrated a novel autocrine mechanism leading to constitutive Wnt signalling in breast cancer, which could be suppressed by SFRP1 and DKK1. Taken together, these results suggest that loss of SFRP1 function is a key mechanism by which Wnt signalling is activated in breast cancer.…”

Macrophage migration inhibitory factor (MIF) promotes cell survival by activation of the Akt pathway and role for CSN5/JAB1 in the control of autocrine MIF activity

“…HeLa/HtTA8/8 cells stably expressing MIF under control of a Tet-off cassette were cultured and induced as described (Nguyen et al, 2003). The normal mammary epithelial cell line MCF-12A and the breast carcinoma cell lines MCF-7 (infiltrating ductal adenocarcinoma), MDA-MB-468 (infiltrating adenocarcinoma) and ZR-75-1 (infiltrating ductal carcinoma) were obtained from the Dahl lab (source ATCC) and were cultured as described previously (Veeck et al, 2006). Briefly, MCF-12A cells were cultured in MDEM medium containing 10% FCS and were additionally supplemented with 10 mg/ml insulin, 500 ng/ml hydrocortisone and 20 ng/ml epidermal growth factor (SigmaAldrich, Munich, Germany).…”

Involvement of genetic instability in the downregulation of sFRP1 in Chinese patients with hepatocellular carcinoma

“…Interestingly, sFRP1 functions as a negative regulator of the Wnt pathway and blocks the activation of the downstream target genes (Kawano and Kypta, 2003). Downregulation of the sFRP1 has been found in a variety of malignancies including colon (Caldwell et al, 2004), breast (Veeck et al, 2006), bladder (Stoehr et al, 2004), ovarian (Takada et al, 2004), and lung (Fukui et al, 2005) cancers. It has been reported that reconstitution of sFRP1 inhibits HCC growth in vitro and in vivo, and the sFRP1 restoration offers a potential therapeutic approach for treatment of HCC (Hu et al, 2009;Jiang et al, 2010).…”

“…Decrease in the sFRP1 expression due to promoter hypermethylation may result in the activation of the Wnt pathway and consequent tumor development. Interestingly, reduced expression of sFRP1 has been found in many malignancies, including colorectal (Caldwell et al, 2004;Suzuki et al, 2004), lung (Fukui et al, 2005), ovarian (Takada et al, 2004), breast (Veeck et al, 2006), esophageal (Zou et al, 2005;Clement et al, 2006), and liver (Shih et al, 2006) cancers.…”