title: Integrated analysis of genome-wide methylation and gene expression shows epigenetic regulation of CYP11B2 in aldosteronomas.
abstract: BACKGROUND
  Differential methylation of CpG regions is the best-defined mechanism of epigenetic regulation of gene expression.
  
  
  OBJECTIVE
  Our objective was to determine whether any changes in methylation are associated with aldosteronomas.
  
  
  METHODS
  We performed integrated genome-wide methylation and gene expression profiling in aldosteronomas (n = 25) as compared with normal adrenal cortical tissue (n = 10) and nonfunctioning adrenocortical tumors (n = 13). To determine the effect of demethylation on gene expression of CYP11B2, the H295R cell line was used.
  
  
  RESULTS
  The methylome of aldosteronomas, normal adrenal cortex, and nonfunctioning adrenocortical tumors was distinct, with hypomethylation of aldosteronomas. Integrated analysis of gene expression and methylation status showed that 53 of 60 genes were hypermethylated and downregulated, or hypomethylated and upregulated, in aldosteronomas. Of these, 3 genes that regulate steroidogenic signals and synthesis in adrenocortical cells were differentially methylated: AVPR1α and PRKCA were downregulated and hypermethylated, and CYP11B2 was upregulated and hypomethylated. Demethylation treatment resulted in upregulation of these genes, with direct hypomethylation of CpG sites associated with the genes. The CpG island in the promoter region of CYP11B2 was hypomethylated in aldosteronomas but not in blood DNA from the same patients (P = .0004).
  
  
  CONCLUSIONS
  Altered methylation in aldosteronomas is associated with dysregulated expression of genes involved in steroid biosynthesis. Aldosteronomas are hypomethylated, and CYP11B2 is overexpressed and hypomethylated in these tumors.
authors.affiliation: Endocrine Oncology (B.H., M.J., L.Z., E.K.) and Genetics (Y.W., P.G.M.) Branches, National Cancer Institute, and Section on Endocrinology and Genetics (P.X., F.R.F, C.A.S.), Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892.
authors.forename: Brandi
authors.initials: B
authors.lastname: Howard
authors.forename: Yonghong
authors.initials: Y
authors.lastname: Wang
authors.forename: Paraskevi
authors.initials: P
authors.lastname: Xekouki
authors.forename: Fabio R
authors.initials: FR
authors.lastname: Faucz
authors.forename: Meenu
authors.initials: M
authors.lastname: Jain
authors.forename: Lisa
authors.initials: L
authors.lastname: Zhang
authors.forename: Paul G
authors.initials: PG
authors.lastname: Meltzer
authors.forename: Constantine A
authors.initials: CA
authors.lastname: Stratakis
authors.forename: Electron
authors.initials: E
authors.lastname: Kebebew
mesh_terms: D000306:Adrenal Cortex Neoplasms / Q000235:genetics* / Q000378:metabolism; D018246:Adrenocortical Adenoma / Q000235:genetics* / Q000378:metabolism; D000328:Adult; D000368:Aged; D000450:Aldosterone / Q000378:metabolism; D018899:CpG Islands / Q000235:genetics; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D006929:Hyperaldosteronism / Q000235:genetics; D008297:Male; D008875:Middle Aged; D018511:Systems Integration; D055815:Young Adult
chemical_list: D000450:Aldosterone; D019405:Cytochrome P-450 CYP11B2