title: Epigenetic alterations in sperm DNA associated with testicular cancer treatment.
abstract: DNA methylation, a key component of the epigenome involved in regulating gene expression, is initially acquired in the germ line at millions of sites across the genome. Altered sperm methylation patterns are associated with infertility and transgenerational effects in humans and rodents. Testicular cancer is the most common form of cancer among men of reproductive age and has a high cure rate associated with chemotherapy treatment with bleomycin, etoposide, and cis-platinum (BEP). Although these drugs result in improved survival, they also affect the number and quality of germ cells. Our goal was to assess germ cell methylation patterns in a rodent model emulating the BEP treatment regimens used in human testicular cancer treatment. Animals were treated with control, or 0.3× (low) or 0.6× (high) dose of BEP, where a 1× dose is equivalent to human treatment regimens. Both dose-dependent and germ cell-dependent DNA methylation alterations were found at numerous loci throughout the genome. Of about 3000 loci tested, 42 loci were affected by BEP at the round spermatid stage of germ cell development, whereas 101 loci were affected in spermatozoa; 15 loci were consistently altered in spermatozoa of all high dose-treated rats. Both hyper- and hypomethylation were detected, suggesting either an interference with normal methylation patterning or abnormal repair of damaged patterns during spermatogenesis. The results indicate that a combination chemotherapy regimen used for testicular cancer treatment can result in altered DNA methylation patterns in spermatozoa and that some loci are more susceptible to damage than others.
authors.affiliation: Research Institute of the McGill University Health Centre at Montreal Children's Hospital, Montreal, Quebec H3Z 2Z3, Canada.
authors.forename: Donovan
authors.initials: D
authors.lastname: Chan
authors.forename: Géraldine
authors.initials: G
authors.lastname: Delbès
authors.forename: Mylène
authors.initials: M
authors.lastname: Landry
authors.forename: Bernard
authors.initials: B
authors.lastname: Robaire
authors.forename: Jacquetta M
authors.initials: JM
authors.lastname: Trasler
mesh_terms: D000818:Animals; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000633:toxicity*; D001761:Bleomycin / Q000633:toxicity; D002945:Cisplatin / Q000633:toxicity; D019175:DNA Methylation / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D044127:Epigenesis, Genetic / Q000187:drug effects*; D005047:Etoposide / Q000633:toxicity; D018392:Genomic Imprinting / Q000187:drug effects; D008297:Male; D051381:Rats; D011914:Rats, Inbred BN; D018570:Risk Assessment; D013091:Spermatogenesis / Q000187:drug effects* / Q000235:genetics; D013094:Spermatozoa / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D013736:Testicular Neoplasms / Q000188:drug therapy*
chemical_list: D001761:Bleomycin; D005047:Etoposide; D002945:Cisplatin