title: Aberrant promoter hypermethylation of the death-associated protein kinase gene is early and frequent in murine lung tumors induced by cigarette smoke and tobacco carcinogens.
abstract: Loss of expression of the death-associated protein (DAP)-kinase gene by aberrant promoter methylation may play an important role in cancer development and progression. The purpose of this investigation was to determine the commonality for inactivation of the DAP-kinase gene in adenocarcinomas induced in mice by chronic exposure to mainstream cigarette smoke, the tobacco carcinogens 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) and vinyl carbamate, and the occupational carcinogen methylene chloride. The timing for inactivation was also determined in alveolar hyperplasias that arise in lung cancer induced in the A/J mouse by NNK. The DAP-kinase gene was not expressed in three of five NNK-induced lung tumor-derived cell lines or in a spontaneously arising lung tumor-derived cell line. Treatment with 5-aza-2'-deoxycytidine restored expression; dense methylation throughout the DAP-kinase CpG island detected by bisulfite sequencing supported methylation as the inactivating event in these cell lines. Methylation-specific PCR detected inactivation of the DAP-kinase gene in 43% of tumors associated with cigarette smoke, a frequency similar to those reported in human non-small cell lung cancer. In addition, DAP-kinase methylation was detected in 52%, 60%, and 50% of tumors associated with NNK, vinyl carbamate, and methylene chloride, respectively. Methylation was observed at similar prevalence in both NNK-induced hyperplasias and adenocarcinomas (46% versus 52%), suggesting that inactivation of this gene is one pathway for tumor development in the mouse lung. Bisulfite sequencing of both premalignant and malignant lesions revealed dense methylation, substantiating that this gene is functionally inactivated at the earliest histological stages of adenocarcinoma development. This study is the first to use a murine model of cigarette smoke-induced lung cancer and demonstrate commonality for inactivation by promoter hypermethylation of a gene implicated in the development of this disease in humans.
authors.affiliation: Lung Cancer Program, Lovelace Respiratory Research Institute, Albuquerque, New Mexico 87108, USA.
authors.forename: Leah C
authors.initials: LC
authors.lastname: Pulling
authors.forename: Brian R
authors.initials: BR
authors.lastname: Vuillemenot
authors.forename: Julie A
authors.initials: JA
authors.lastname: Hutt
authors.forename: Theodora R
authors.initials: TR
authors.lastname: Devereux
authors.forename: Steven A
authors.initials: SA
authors.lastname: Belinsky
mesh_terms: D000818:Animals; D051017:Apoptosis Regulatory Proteins; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics*; D002273:Carcinogens / Q000633:toxicity*; D045744:Cell Line, Tumor; D018899:CpG Islands; D019175:DNA Methylation / Q000187:drug effects; D064550:Death-Associated Protein Kinases; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D020868:Gene Silencing / Q000187:drug effects; D006965:Hyperplasia; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000139:chemically induced / Q000209:etiology* / Q000235:genetics*; D008752:Methylene Chloride / Q000633:toxicity; D051379:Mice; D008805:Mice, Inbred A; D009602:Nitrosamines / Q000633:toxicity*; D011401:Promoter Regions, Genetic / Q000187:drug effects; D012907:Smoking / Q000009:adverse effects*; D014520:Urethane / Q000031:analogs & derivatives* / Q000633:toxicity
chemical_list: D051017:Apoptosis Regulatory Proteins; D002273:Carcinogens; D009602:Nitrosamines; D014520:Urethane; D008752:Methylene Chloride; C016583:4-(N-methyl-N-nitrosamino)-1-(3-pyridyl)-1-butanone; C017963:vinyl carbamate; D064550:Death-Associated Protein Kinases; D017871:Calcium-Calmodulin-Dependent Protein Kinases