Abstract
Background
Gene silencing via promoter hypermethylation plays a crucial role in the pathogenesis of cancers. Neuronal pentraxin II (NPTX2) has been observed to be hypermethylated in pancreatic cancers. Methylation of NPTX2 might provide a novel diagnostic marker for pancreatic cancers.
Aim
The objective of this study is to investigate the abnormal patterns of DNA methylation of NPTX2 in pancreatic cancers, and its role in the transcriptional silencing of NPTX2.
Methods
NPTX2 expression was detected by reverse-transcription polymerase chain reaction (RT-PCR), and the methylation status of NPTX2 was assessed by methylation-specific polymerase chain reaction (MSP). Immunohistochemistry was used to examine the NPTX2 protein expression. The pancreatic cancer cell lines were treated with the DNA methyltransferase inhibitor, histone deacetylase inhibitors, either alone or in combination.
Results
The MSP analysis revealed that the promoter region of NPTX2 gene was largely unmethylated in normal pancreatic tissues, while NPTX2 was frequently hypermethylated in pancreatic cancer cells and in primary pancreatic carcinomas. Quantitative RT-PCR revealed that the mean mRNA expression level of NPTX2 in the pancreatic cancer tissues was significantly lower than that in the paired adjacent normal tissues (0.96 ± 0.91 vs. 2.78 ± 1.42, P < 0.001). Consistent with RT-PCR detection, treatment with 5Aza-dC resulted in different degrees of induction of NPTX2 protein in the various cancer cell lines.
Conclusion
We demonstrate that the NPTX2 protein is down-regulated in human primary pancreatic cancers and in pancreatic cancer cell lines. This study provides the first evidence that the down-regulation of NPTX2 tightly correlates with its promoter hypermethylation.
Similar content being viewed by others
References
Jones PA, Takai D. The role of DNA methylation in mammalian epigenetics. Science. 2001;293:1068–1070.
Sved J, Bird A. The expected equilibrium of the CpG dinucleotide in vertebrate genomes under a mutation model. Proc Natl Acad Sci USA. 1990;87:4692–4696.
Bonfils C, Beaulieu N, Chan E, Cotton-Montpetit J, MacLeod AR. Characterization of the human DNA methyltransferase splice variant Dnmt1b. J Bio Chem. 2000;275:10754–10760.
Maiumder S, Ghoshal K, Datta J, Smith DS, Bai S, Jacob ST. Ribosomal RNA gene transcription role of DNA methyltransferases in regulation of human. J Bio Chem. 2006;281:22062–22072.
Issa JP, Ottaviano YL, Celano P, Hamilton SR, Davidson NE, Baylin SB. Methylation of the oestrogen receptor CpG island links ageing and neoplasia in human colon. Nat Genet. 1994;7:536–540.
Laird PW. The power and the promise of DNA methylation markers. Nat Rev Cancer. 2003;3:253–266.
Karpf AR, Jones DA. Reactivating the expression of methylation silenced genes in human cancer. Oncogene. 2002;21:5496–5503.
Matsubayashi H, Canto M, Sato N, et al. DNA methylation alterations in the pancreatic juice of patients with suspected pancreatic disease. Cancer Res. 2006;66:1208–1217.
Sato N, Parker AR, Fukushima N, et al. Epigenetic inactivation of TFPI-2 as a common mechanism associated with growth and invasion of pancreatic ductal adenocarcinoma. Oncogene. 2005;24:850–858.
Komazaki T, Nagai H, Emi M, et al. Hypermethylation-associated inactivation of the SOCS-1 gene, a JAK/STAT inhibitor, in human pancreatic cancers. Jpn J Clin Oncol. 2004;34:191–194.
Ota N, Kawakami K, Okuda T, et al. Prognostic significance of p16 (INK4a) hypermethylation in non-small cell lung cancer is evident by quantitative DNA methylation analysis. Anticancer Res. 2006;26:3729–3732.
Jeong DH, Youm MY, Kim YN, et al. Promoter methylation of p16, DAPK, CDH1, and TIMP-3 genes in cervical cancer: correlation with clinicopathologic characteristics. Int J Gynecol Cancer. 2006;16:1234–1240.
Attri J, Srinivasan R, Majumdar S, Radotra BD, Wig J. Alterations of tumor suppressor gene p16INK4a in pancreatic ductal carcinoma. BMC Gastroenterol. 2005;5:22.
Ling ZQ, Li P, Ge MH, et al. Aberrant methylation of different DNA repair genes demonstrates distinct prognostic value for esophageal cancer. Dig Dis Sci. 2011;56:2992–3004.
Guo XQ, Wang SJ, Zhang LW, Wang XL, Zhang JH, Guo W. DNA methylation and loss of protein expression in esophageal squamous cell carcinogenesis of high-risk area. J Exp Clin Cancer Res. 2007;26:587–594.
Zhang L, Gao J, Li L, Li Z, Du Y, Gong Y. The neuronal pentraxin II gene (NPTX2) inhibit proliferation and invasion of pancreatic cancer cells in vitro. Mol Biol Rep. 2011;38:4903–4911.
Sato N, Fukushima N, Maitra A, et al. Discovery of novel targets for aberrant methylation in pancreatic carcinoma using high-throughput microarrays. Cancer Res. 2003;63:3735–3742.
Eads CA, Danenberg KD, Kawakami K, et al. MethyLight: a high-throughput assay to measure DNA methylation. Nucleic Acids Res. 2000;28:E32.
Meehan RR, Stancheva I. DNA methylation and control of gene expression in vertebrate development. Essays Biochem. 2001;37:59–70.
de Maat MF, van de Velde CJ, Umetani N, et al. Epigenetic silencing of cyclooxygenase-2 affects clinical outcome in gastric cancer. J Clin Oncol. 2007;25:4887–4894.
Sato N, Fukushima N, Chang R, Matsubayashi H, Goggins M. Differential and epigenetic gene expression profiling identifies frequent distribution of the RELN pathway in pancreatic cancers. Gastroenterology. 2006;130:548–565.
Mori Y, Cai K, Cheng Y, et al. A genome-wide search identifies epigenetic silencing of Somatostatin, Tachykinin-1, and 5 other genes in colon cancer. Gastroenterology. 2006;131:797–808.
Peng DF, Kanai Y, Sawada M, et al. DNA methylation of multi tumor-related genes in association with overexpression of DNA methytransferase 1 (DNMT1) during multistage carcinogenesis of the pancreas. Carcinogenesis. 2006;27:1160–1168.
Yang X, Phillips DL, Ferguson AT, Nelson WG, Herman JG, Davidson NE. Synergistic activation of functional estrogen receptor (ER)-alpha by DNA methyltransferase and histone deacetylase inhibition in human ER-alpha-negative breast cancer cells. Cancer Res. 2001;61:7025–7029.
Primeau M, Gagnon J, Momparler RL. Synergistic antineoplastic action of DNA methylation inhibitor 5-AZA-2′-deoxycytidine and histone deacetylase inhibitor depsipeptide on human breast carcinoma cells. Int J Cancer. 2003;103:177–184.
Xiong Y, Dowdy SC, Podratz KC, et al. Histone deacetylase inhibitors decrease DNA methyltransferase-3B messenger RNA stability and down-regulate de novo DNA methyltransferase activity in human endometrial cells. Cancer Res. 2005;65:2684–2689.
Ueki T, Toyota M, Sohn T, et al. Hypermethylation of multiple genes in pancreatic adenocarcinoma. Cancer Res. 2000;60:1835–1839.
Conflict of interest
None.
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Zhang, L., Gao, J., Li, Z. et al. Neuronal pentraxin II (NPTX2) Is Frequently Down-Regulated by Promoter Hypermethylation in Pancreatic Cancers. Dig Dis Sci 57, 2608–2614 (2012). https://doi.org/10.1007/s10620-012-2202-8
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s10620-012-2202-8