Aberrant methylation of LINE-1, SLIT2, MAL and IGFBP7 in non-small cell lung cancer

MAKOTO SUZUKI, KENJI SHIRAISHI, AYAMI EGUCHI, KOEI IKEDA, TAKESHI MORI, KENTARO YOSHIMOTO, YASUOMI OHBA, TATSUYA YAMADA, TAKAAKI ITO, YOSHIFUMI BABA, HIDEO BABA
2013 Oncology Reports  
Genome-wide DNA hypomethylation and gene hypermethylation play important roles in instability and carcino genesis. Methylation in long interspersed nucleotide element 1 (LINE-1) is a good indicator of the global DNA methylation level within a cell. Slit homolog 2 (SLIT2), myelin and lymphocyte protein gene (MAL) and insulin-like growth factor binding protein 7 (IGFBP7) are known to be hypermethylated in various malignancies. The aim of the present study was to assess the precise methylation
more » ... ls of LINE-1, SLIT2, MAL and IGFBP7 in non-small cell lung cancer (NSCLC) using a pyrosequencing assay. Methylation of all regions was examined in 56 primary NSCLCs using a pyrosequencing assay. Changes in mRNA expression levels of SLIT2, MAL and IGFBP7 were measured before and after treatment with a demethylating agent. Methylation of these genes was also examined in 9 lung cancer cell lines using RT-PCR and a pyrosequencing assay. Frequencies of hypomethylation of LINE-1 and hypermethylation of SLIT2, MAL and IGFBP7, defined by predetermined cut off values, were 55, 64, 46 and 54% in NSCLCs, respectively and exhibited tumor-specific features. The hypermethylation of all genes was well correlated with changes in expression. The methylation level and frequency of MAL were significantly higher in smokers and in patients without EGFR mutations. Through accurate measurement of methylation levels using pyrosequencing, hypomethylation of LINE-1 and hypermethylation of SLIT2, MAL and IGFBP7 were frequently detected in NSCLCs and associated with various clinical features. Analysis of the methylation profiles of these genes may, therefore, provide novel opportunities for the therapy of NSCLCs. Abbreviations: LINE-1, long interspersed nucleotide element 1; SLIT2, slit homolog 2; MAL, myelin and lymphocyte protein gene; IGFBP7, insulin-like growth factor binding protein 7; NSCLC, non-small cell lung cancer
doi:10.3892/or.2013.2266 pmid:23381221 pmcid:PMC3621652 fatcat:mzr3gk6fjbgnxl7bnkeokbw53a