¹Department of Biochemistry & Molecular Biology, UF-Shands Cancer Center Program in Cancer Genetics, Epigenetics and Tumor Virology and Genetics Institute, College of Medicine, University of Florida, Gainesville, FL, USA

Correspondence: Dr KD Robertson, Department of Biochemistry & Molecular Biology, UF-Shands Cancer Center Program in Cancer Genetics, Epigenetics and Tumor Virology and Genetics Institute, College of Medicine, University of Florida, Box 100245, 1600 S.W. Archer Road, Gainesville, FL 32610, USA. E-mail: keithr@ufl.edu

Received 22 June 2006; Revised 31 August 2006; Accepted 1 September 2006; Published online 9 October 2006.

Abstract

Lung cancer is the leading cause of cancer-related deaths in the United States due, in large part, to the lack of early detection methods. Lung cancer arises from a complex series of genetic and epigenetic changes leading to uncontrolled cell growth and metastasis. Unlike genetic changes, epigenetic changes, such as DNA methylation and histone acetylation, are reversible with currently available pharmaceuticals and are early events in lung tumorigenesis detectable by non-invasive methods. In order to better understand how epigenetic changes contribute to lung cancer, and to identify new disease biomarkers, we combined pharmacologic inhibition of DNA methylation and histone deacetylation in non-small cell lung cancer (NSCLC) cell lines, with genome-wide expression profiling. Of the more than 200 genes upregulated by these treatments, three of these, neuronatin, metallothionein 3 and cystatin E/M, were frequently hypermethylated and transcriptionally downregulated in NSCLC cell lines and tumors. Interestingly, four other genes, cylindromatosis, CD9, activating transcription factor 3 and oxytocin receptor, were dominantly regulated by histone deacetylation and were also frequently downregulated in lung tumors. The majority of these genes also suppressed NSCLC growth in culture when ectopically expressed. This study therefore reveals new putative NSCLC growth regulatory genes and epigenetic disease biomarkers that may enhance early detection strategies and serve as therapeutic targets.