title: Acute hypersensitivity of pluripotent testicular cancer-derived embryonal carcinoma to low-dose 5-aza deoxycytidine is associated with global DNA Damage-associated p53 activation, anti-pluripotency and DNA demethylation.
abstract: Human embryonal carcinoma (EC) cells are the stem cells of nonseminoma testicular germ cells tumors (TGCTs) and share remarkable similarities to human embryonic stem (ES) cells. In prior work we found that EC cells are hypersensitive to low nanomolar doses of 5-aza deoxycytidine (5-aza) and that this hypersensitivity partially depended on unusually high levels of the DNA methyltransferase, DNMT3B. We show here that low-dose 5-aza treatment results in DNA damage and induction of p53 in NT2/D1 cells. In addition, low-dose 5-aza results in global and gene specific promoter DNA hypomethylation. Low-dose 5-aza induces a p53 transcriptional signature distinct from that induced with cisplatin in NT2/D1 cells and also uniquely downregulates genes associated with pluripotency including NANOG, SOX2, GDF3 and Myc target genes. Changes in the p53 and pluripotency signatures with 5-aza were to a large extent dependent on high levels of DNMT3B. In contrast to the majority of p53 target genes upregulated by 5-aza that did not show DNA hypomethylation, several other genes induced with 5-aza had corresponding decreases in promoter methylation. These genes include RIN1, SOX15, GPER, and TLR4 and are novel candidate tumors suppressors in TGCTs. Our studies suggest that the hypersensitivity of NT2/D1 cells to low-dose 5-aza is multifactorial and involves the combined activation of p53 targets, repression of pluripotency genes, and activation of genes repressed by DNA methylation. Low-dose 5-aza therapy may be a general strategy to treat those tumors that are sustained by cells with embryonic stem-like properties.GEO NUMBER FOR THE MICROARRAY DATA: GSE42647.
authors.affiliation: Department of Pharmacology and Toxicology, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire, United States of America.
authors.forename: Bijesh K
authors.initials: BK
authors.lastname: Biswal
authors.forename: Maroun J
authors.initials: MJ
authors.lastname: Beyrouthy
authors.forename: Mary P
authors.initials: MP
authors.lastname: Hever-Jardine
authors.forename: David
authors.initials: D
authors.lastname: Armstrong
authors.forename: Craig R
authors.initials: CR
authors.lastname: Tomlinson
authors.forename: Brock C
authors.initials: BC
authors.lastname: Christensen
authors.forename: Carmen J
authors.initials: CJ
authors.lastname: Marsit
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Spinella
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology / Q000627:therapeutic use*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001374:Azacitidine / Q000031:analogs & derivatives* / Q000494:pharmacology / Q000627:therapeutic use; D018236:Carcinoma, Embryonal / Q000188:drug therapy* / Q000235:genetics; D045744:Cell Line, Tumor; D004249:DNA Damage / Q000187:drug effects* / Q000235:genetics; D019175:DNA Methylation / Q000187:drug effects*; D000077209:Decitabine; D015536:Down-Regulation / Q000187:drug effects / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D008297:Male; D013736:Testicular Neoplasms / Q000188:drug therapy* / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D000964:Antimetabolites, Antineoplastic; D016159:Tumor Suppressor Protein p53; D000077209:Decitabine; D001374:Azacitidine