title: Unlike pancreatic cancer cells pancreatic cancer associated fibroblasts display minimal gene induction after 5-aza-2'-deoxycytidine.
abstract: OBJECTIVE
  Cancer associated stromal fibroblasts (CAFs) undergo transcriptional and phenotypic changes that contribute to tumor progression, but the mechanisms responsible for these changes are not well understood. Aberrant DNA methylation is an important cause of transcriptional alterations in cancer cells but it is not known how important DNA methylation alterations are to CAF behavior.
  
  
  METHODS
  We used Affymetrix exon arrays to compare genes induced by the DNA methylation inhibitor 5-aza-dC in cultured pancreatic cancer associated fibroblasts, pancreatic control fibroblasts and pancreatic cancer cell lines.
  
  
  RESULTS
  We found that pancreatic CAFs and control pancreatic fibroblasts were less responsive to 5-aza-dC-mediated gene reactivation than pancreatic cancer cells (mean+/-SD of genes induced ≥ 5-fold was 9 ± 10 genes in 10 pancreatic CAF cultures, 17 ± 14 genes in 3 control pancreatic fibroblast cultures, and 134 ± 85 genes in 4 pancreatic cancer cell lines). We examined differentially expressed genes between CAFs and control fibroblasts for candidate methylated genes and identified the disintegrin and metalloprotease, ADAM12 as hypomethylated and overexpressed in pancreatic CAF lines and overexpressed in fibroblasts adjacent to primary pancreatic adenocarcinomas.
  
  
  CONCLUSIONS
  Compared to pancreatic cancer cells, few genes are reactivated by DNMT1 inhibition in pancreatic CAFs suggesting these cells do not harbor many functionally important alterations in DNA methylation. CAFs may also not be very responsive to therapeutic targeting with DNA methylation inhibitors.
authors.affiliation: Department of Pathology, The Sol Goldman Pancreatic Cancer Research Center, The John Hopkins Medical Institutions, Baltimore, Maryland, United States of America.
authors.forename: Jun
authors.initials: J
authors.lastname: Yu
authors.forename: Kimberly
authors.initials: K
authors.lastname: Walter
authors.forename: Noriyuki
authors.initials: N
authors.lastname: Omura
authors.forename: Seung-Mo
authors.initials: SM
authors.lastname: Hong
authors.forename: Angela
authors.initials: A
authors.lastname: Young
authors.forename: Ang
authors.initials: A
authors.lastname: Li
authors.forename: Audrey
authors.initials: A
authors.lastname: Vincent
authors.forename: Michael
authors.initials: M
authors.lastname: Goggins
mesh_terms: D051722:ADAM Proteins / Q000235:genetics / Q000378:metabolism; D000072199:ADAM12 Protein; D001374:Azacitidine / Q000494:pharmacology*; D001483:Base Sequence; D015153:Blotting, Western; D045744:Cell Line, Tumor; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology*; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects*; D052138:Genes, Neoplasm / Q000235:genetics; D056726:Genetic Association Studies; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008875:Middle Aged; D008969:Molecular Sequence Data; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D008565:Membrane Proteins; D012333:RNA, Messenger; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; D051722:ADAM Proteins; D000072199:ADAM12 Protein; C000606480:ADAM12 protein, human; D001374:Azacitidine