title: Methylation of Wnt7a is modulated by DNMT1 and cigarette smoke condensate in non-small cell lung cancer.
abstract: Wnt7a is known to be a tumor suppressor that is lost in NSCLC, but no mechanism of loss has been established. Methylation of promoter regions has been established as a common mechanism of loss of tumor suppressor expression in NSCLC. We previously demonstrated that loss of Wnt7a in non-transformed lung epithelial cell lines led to increased cell growth, altered 3-D culture growth, and increased migration. The Wnt7a promoter has a higher percentage of methylation in NSCLC tumor tissue compared to matched normal lung tissue and methylation of the promoter region leads to decreased activity. We treated H157 and H1299 NSCLC cell lines with 5-Aza-2'-deoxycytidine and detected loss of Wnt7a promoter methylation, increased Wnt7a expression, and increased activity of the Wnt7a lung signaling pathway. When DNMT1 expression was knocked down by shRNA, expression of Wnt7a increased and methylation decreased. Together these data suggest that in NSCLC, Wnt7a is lost by methylation in a subset of tumors and that this methylation is maintained by DNMT1. Restoration of Wnt7a expression through demethylation could be an important therapeutic approach in the treatment of NSCLC.
authors.affiliation: Department of Medicine, University of Colorado School of Medicine, Aurora, Colorado, United States of America. Meredith.tennis@gmail.com
authors.forename: Meredith A
authors.initials: MA
authors.lastname: Tennis
authors.forename: Michelle M
authors.initials: MM
authors.lastname: Vanscoyk
authors.forename: Lora A
authors.initials: LA
authors.lastname: Wilson
authors.forename: Nicole
authors.initials: N
authors.lastname: Kelley
authors.forename: Robert A
authors.initials: RA
authors.lastname: Winn
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D002289:Carcinoma, Non-Small-Cell Lung / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism*; D019175:DNA Methylation / Q000187:drug effects*; D000077209:Decitabine; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008168:Lung / Q000473:pathology; D008175:Lung Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D010641:Phenotype; D011401:Promoter Regions, Genetic / Q000187:drug effects / Q000235:genetics; D012906:Smoke / Q000009:adverse effects*; D012907:Smoking / Q000009:adverse effects*; D051153:Wnt Proteins / Q000235:genetics*
chemical_list: D012906:Smoke; C092778:WNT7A protein, human; D051153:Wnt Proteins; D000077209:Decitabine; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; D001374:Azacitidine