Details

Autor(en) / Beteiligte

• Shao, Chunbo
• Tan, Marietta
• Bishop, Justin A.
• Vikani, Ami R.
• Ha, Patrick K.

Titel

Abstract 5017: DNA methylation array screening in salivary gland adenoid cystic carcinoma

Ist Teil von

• Cancer research (Chicago, Ill.), 2012-04, Vol.72 (8_Supplement), p.5017-5017

Erscheinungsjahr

2012

Link zum Volltext

Quelle

EZB Free E-Journals

Beschreibungen/Notizen

• Abstract Objective: DNA methylation alterations, with either gain or loss of CpG methylation in the promoter region, can alter the expression of tumor suppressor genes or oncogenes. This contributes to the tumorigenesis of human cancers, including salivary adenoid cystic carcinoma (ACC). In this study, we used a DNA methylation array (Illumina HumanMethylation27 BeadChip, San Diego, CA) to screen for novel oncogene and tumor suppressor gene (TSG) candidates under the control of promoter methylation in ACC. Methods: The Illumina HumanMethylation27 BeadChip Array was used to analyze the DNA methylation patterns of ∼14.000 genes at 27,578 CpG sites in 21 ACC and 13 normal salivary gland tissues. With our basic screening algorithm, we narrowed the list down to ∼100 tumor suppressor gene candidates (hypermethylated in tumor) and oncogene candidates (hypomethylated in tumor). Next, the differential methylation levels in the promoter region of candidates were validated by bisulfite genomic sequencing in four primary ACC and four normal salivary gland tissues. Candidate genes that showed differential methylation were then confirmed by analyzing gene re-expression in seven cell lines treated with 5-Aza deoxycytidine, a global demethylating agent. Furthermore, the expression levels of the candidate genes were examined by quantitative reverse transcription PCR (qRT-PCR) in a separate ACC cohort. Lastly, the DNA methylation levels of promising candidate genes were validated by quantitative methylation specific PCR (qMSP) in a larger ACC cohort. Results: With the methylation array, we initially identified 28 oncogene candidates which displayed relative hypomethylation and 64 TSG candidates that showed relative hypermethylation in ACC compared to normal tissues. After the above mentioned additional validation steps were performed, we settled on two promising candidates, PDE9A and TP53TG3, that were significantly hypomethylated and overexpressed in primary ACC tumors compared to normal salivary gland tissue. Furthermore, the expression of PDE9A and TP53TG3 demonstrated consistent upregulation after 5-aza-cytidine treatment of cancer cell lines, suggesting that promoter methylation does play in a role in controlling gene expression. Conclusions: The Illumina HumanMethylation27 BeadChip array is a reliable and efficient tool for analyzing global gene methylation. It is useful in screening for novel oncogene and TSG candidates controlled by promoter methylation in salivary gland ACC. PDE9A and TP53TG3 were identified as promising novel oncogene candidates in salivary gland ACC. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 5017. doi:1538-7445.AM2012-5017