title: Long-term epigenetic therapy with oral zebularine has minimal side effects and prevents intestinal tumors in mice.
abstract: Recent successes in the application of epigenetic drugs for the treatment of myelodysplastic syndrome have raised questions on the safety of long-term administration of DNA methylation inhibitors. We treated preweaned cancer prone Apc(Min/+) (Min) mice continuously with the DNA methylation inhibitor zebularine in their drinking water to determine the effects of the drug on normal mouse development as well as cancer prevention. Zebularine caused a tissue-specific reduction in DNA methylation at B1 short interspersed nucleotide elements in the small and large intestines of female Min mice but not in other organs examined after chronic oral treatment. No significant difference in the average weights of mice was observed during the treatment. In addition, analysis of global gene expression of colonic epithelial cells from the females indicated that only 3% to 6% of the genes were affected in their expression. We did not detect toxicity and abnormalities from the histopathologic analysis of liver and intestinal tissues. Lastly, we tested whether prevention of tumorigenesis can be achieved with chronic oral administration of zebularine in Min mice. The average number of polyps in Min females decreased from 58 to 1, whereas the average polyp number remained unaffected in Min males possibly due to differential activity of aldehyde oxidase. Taken together, our results show for the first time that long-term oral administration of zebularine causes a gender-specific abrogation of intestinal tumors while causing a tissue-specific DNA demethylation. Importantly, prolonged treatment of mice with epigenetic drugs resulted in only minor developmental and histologic changes.
authors.affiliation: Department of Biochemistry and Molecular Biology, Keck School of Medicine, University of Southern California, Los Angeles, California 90033-9181, USA.
authors.forename: Christine B
authors.initials: CB
authors.lastname: Yoo
authors.forename: Jody C
authors.initials: JC
authors.lastname: Chuang
authors.forename: Hyang-Min
authors.initials: HM
authors.lastname: Byun
authors.forename: Gerda
authors.initials: G
authors.lastname: Egger
authors.forename: Allen S
authors.initials: AS
authors.lastname: Yang
authors.forename: Louis
authors.initials: L
authors.lastname: Dubeau
authors.forename: Tiffany
authors.initials: T
authors.lastname: Long
authors.forename: Peter W
authors.initials: PW
authors.lastname: Laird
authors.forename: Victor E
authors.initials: VE
authors.lastname: Marquez
authors.forename: Peter A
authors.initials: PA
authors.lastname: Jones
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000009:adverse effects / Q000494:pharmacology; D002277:Carcinoma / Q000235:genetics / Q000517:prevention & control*; D003562:Cytidine / Q000008:administration & dosage / Q000009:adverse effects / Q000031:analogs & derivatives* / Q000494:pharmacology; D019175:DNA Methylation / Q000187:drug effects; D044127:Epigenesis, Genetic / Q000187:drug effects*; D005260:Female; D020869:Gene Expression Profiling; D017491:Genes, APC; D007413:Intestinal Mucosa / Q000378:metabolism; D007414:Intestinal Neoplasms / Q000235:genetics / Q000517:prevention & control*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D009928:Organ Specificity / Q000187:drug effects; D012727:Sex Characteristics; D013997:Time Factors
chemical_list: D000964:Antimetabolites, Antineoplastic; D003562:Cytidine; C009131:pyrimidin-2-one beta-ribofuranoside