Frequent epigenetic inactivation of secreted frizzled-related protein 2 (SFRP2) by promoter methylation in human gastric cancer

The role of secreted frizzled-related protein (SFRP) genes in gastric cancer remains largely unknown. We determined the frequency and functional significance of SFRPs hypermethylation in human gastric cancer. The expression and methylation status of four SFRP members (SFRP1, 2, 4, and 5) in primary gastric cancer samples was screened. The biological effects of SFRP were analysed by flow cytometry, cell viability assay and in vivo tumour growth in nude mice. Among the four SFRPs, only SFRP2 was significantly downregulated in gastric cancer as compared to adjacent non-cancer samples (P<0.01). Promoter hypermethylation of SFRP2 was detected in 73.3% primary gastric cancer tissues, 37.5% of samples showing intestinal metaplasia and 20% adjacent normal gastric tissues. Bisulphite DNA sequencing confirmed the densely methylated SFRP2 promoter region. Demethylation treatment restored the expression of SFRP2 in gastric cancer cell lines. Forced expression of SFRP2 induced cell apoptosis, inhibited proliferation of gastric cancer cells and suppressed tumour growth in vivo. Moreover, methylated SFRP2 was detected in 66.7% of serum samples from cancer patients but not in normal controls. In conclusion, epigenetic inactivation of SFRP2 is a common and early event contributing to gastric carcinogenesis and may be a potential biomarker for gastric cancer.

[1]  W. Leung,et al.  Detection of gene promoter hypermethylation in the tumor and serum of patients with gastric carcinoma. , 2002, Clinical cancer research : an official journal of the American Association for Cancer Research.

[2]  S. Nishizuka,et al.  Promoter methylation status of E-cadherin, hMLH1, and p16 genes in nonneoplastic gastric epithelia. , 2002, The American journal of pathology.

[3]  P. Polakis.  The many ways of Wnt in cancer. , 2007, Current opinion in genetics & development.

[4]  Takayuki Fukui,et al.  Transcriptional silencing of secreted frizzled related protein 1 (SFRP1) by promoter hypermethylation in non-small-cell lung cancer , 2005, Oncogene.

[5]  O. Madsen,et al.  Expression patterns of Wnts, Frizzleds, sFRPs, and misexpression in transgenic mice suggesting a role for Wnts in pancreas and foregut pattern formation , 2002, Developmental dynamics : an official publication of the American Association of Anatomists.

[6]  C. Marsit,et al.  Epigenetic inactivation of SFRP genes and TP53 alteration act jointly as markers of invasive bladder cancer. , 2005, Cancer research.

[7]  M. Ilyas,et al.  Wnt signalling and the mechanistic basis of tumour development , 2005, The Journal of pathology.

[8]  M. Mahadevappa,et al.  SARPs: a family of secreted apoptosis-related proteins. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[9]  H. Kirikoshi,et al.  Expression profiles of 10 members of Frizzled gene family in human gastric cancer. , 2001, International journal of oncology.

[10]  F. Chan,et al.  Alterations of frizzled (FzE3) and secreted frizzled related protein (hsFRP) expression in gastric cancer. , 2001, Life sciences.

[11]  D. Ahlquist,et al.  Aberrant methylation of secreted frizzled‐related protein genes in esophageal adenocarcinoma and Barrett's esophagus , 2005, International journal of cancer.

[12]  W. Leung,et al.  Effects of Helicobacter pylori Eradication on Methylation Status of E-Cadherin Gene in Noncancerous Stomach , 2006, Clinical Cancer Research.

[13]  Matty P. Weijenberg,et al.  A genomic screen for genes upregulated by demethylation and histone deacetylase inhibition in human colorectal cancer , 2002, Nature Genetics.

[14]  Jun Yu,et al.  Promoter hypermethylation of tumor‐related genes in gastric intestinal metaplasia of patients with and without gastric cancer , 2002, International journal of cancer.

[15]  G. Tamura.  Genetic and epigenetic alterations of tumor suppressor and tumor-related genes in gastric cancer. , 2002, Histology and histopathology.

[16]  F. Chan,et al.  Potential diagnostic and prognostic values of detecting promoter hypermethylation in the serum of patients with gastric cancer , 2005, British Journal of Cancer.

[17]  Wei Dong Chen,et al.  Epigenetic inactivation of SFRP genes allows constitutive WNT signaling in colorectal cancer , 2004, Nature Genetics.

[18]  J. Kim,et al.  Human secreted frizzled-related protein is down-regulated and induces apoptosis in human cervical cancer. , 2002, Experimental cell research.

[19]  C. Marsit,et al.  Epigenetic inactivation of the SFRP genes is associated with drinking, smoking and HPV in head and neck squamous cell carcinoma , 2006, International journal of cancer.

[20]  Jun Yu,et al.  Concurrent hypermethylation of multiple tumor‐related genes in gastric carcinoma and adjacent normal tissues , 2001, Cancer.

[21]  Robert Brown,et al.  Hypermethylation of 18S and 28S Ribosomal DNAs Predicts Progression-Free Survival in Patients with Ovarian Cancer , 2005, Clinical Cancer Research.

[22]  D. Ichikawa,et al.  Comparison of methylation‐specific polymerase chain reaction (MSP) with reverse transcriptase‐polymerase chain reaction (RT‐PCR) in peripheral blood of gastric cancer patients , 2004, Journal of surgical oncology.

[23]  P. Malfertheiner,et al.  Absence of cyclin D2 expression is associated with promoter hypermethylation in gastric cancer , 2003, British Journal of Cancer.

[24]  W. H. Kim,et al.  CpG island methylation in premalignant stages of gastric carcinoma. , 2001, Cancer research.