DNA methylation profiling revealed prometer hypermethylation-induced silencing of p16, DDAH2 and DUSP1 in primary oral squamous cell carcinoma

Khor, G.H. and Froemming, G.R.A. and Zain, R.B. and Abraham, M.T. and Omar, E. and Tan, S.K. and Tan, A.C. (2013) DNA methylation profiling revealed prometer hypermethylation-induced silencing of p16, DDAH2 and DUSP1 in primary oral squamous cell carcinoma. International Journal of Medical Sciences, 10 (12). pp. 1727-1739. ISSN 1449-1907

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Abstract

Background: Hypermethylation in promoter regions of genes might lead to altered gene functions and result in malignant cellular transformation. Thus, biomarker identification for hypermethylated genes would be very useful for early diagnosis, prognosis, and therapeutic treatment of oral squamous cell carcinoma (OSCC). The objectives of this study were to screen and validate differentially hypermethylated genes in OSCC and correlate the hypermethylation-induced genes with demographic, clinocopathological characteristics and survival rate of OSCC. Methods: DNA methylation profiling was utilized to screen the differentially hypermethylated genes in OSCC. Three selected differentially-hypermethylated genes of p16, DDAH2 and DUSP1 were further validated for methylation status and protein expression. The correlation between demographic, clinicopathological characteristics, and survival rate of OSCC patients with hypermethylation of p16, DDAH2 and DUSP1 genes were analysed in the study. Results: Methylation profiling demonstrated 33 promoter hypermethylated genes in OSCC. The differentially-hypermethylated genes of p16, DDAH2 and DUSP1 revealed positivity of 78%, 80% and 88% in methylation-specific polymerase chain reaction and 24% and 22% of immunoreactivity in DDAH2 and DUSP1 genes, respectively. Promoter hypermethylation of p16 gene was found significantly associated with tumour site of buccal, gum, tongue and lip (P=0.001). In addition, DDAH2 methylation level was correlated significantly with patients' age (P=0.050). In this study, overall five-year survival rate was 38.1% for OSCC patients and was influenced by sex difference. Conclusions: The study has identified 33 promoter hypermethylated genes that were significantly silenced in OSCC, which might be involved in an important mechanism in oral carcinogenesis. Our approaches revealed signature candidates of differentially hypermethylated genes of DDAH2 and DUSP1 which can be further developed as potential biomarkers for OSCC as diagnostic, prognostic and therapeutic targets in the future.

Item Type: Article
Additional Information: Corresponding author: Kwai Lin Thong, Institute of Biological Science, Faculty of Science, University of Malaya, 50603, Kuala Lumpur, Malaysia. E-mail: thongkl@um.edu.my. Tel: +603-79674437 Fax: +603-79675908 Or Goot Heah Khor, Centre of Studies for Preclinical Science, Faculty of Dentistry, Universiti Teknologi MARA, 40450. Shah Alam, Selangor, Malaysia. E-mail: gootheah@salam.uitm.edu.my Tel: +603-55435814 Fax: +603-55435803. --- © Ivyspring International Publisher. This is an open-access article distributed under the terms of the Creative Commons License (http://creativecommons.org/ licenses/by-nc-nd/3.0/). Reproduction is permitted for personal, noncommercial use, provided that the article is in whole, unmodified, and properly cited.
Uncontrolled Keywords: DNA methylation profiling; promoter hypermethylation; Oral Squamous Cell Carcinoma; DDAH2; DUSP1; protein expression
Subjects: R Medicine > RK Dentistry
Divisions: Faculty of Dentistry > Dept of Oral Pathology & Oral Medicine & Periodontology
Depositing User: Mr Ahmad Azwan Azman
Date Deposited: 24 Jan 2014 02:51
Last Modified: 24 Jan 2014 02:51
URI: http://eprints.um.edu.my/id/eprint/9127

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