title: Chromosome loss caused by DNA fragmentation induced in main nuclei and micronuclei of human lymphoblastoid cells treated with colcemid.
abstract: Aneuploidy, a change in the number of chromosomes, plays an essential role in tumorigenesis. Our previous study demonstrated that a loss of a whole chromosome is induced in human lymphocytes by colcemid, a well-known aneugen. Here, to clarify the mechanism for colcemid-induced chromosome loss, we investigated the relationship between chromosome loss and DNA fragmentation in human lymphoblastoid cells treated with colcemid (an aneugen) compared with methyl methanesulfonate (MMS; a clastogen). We analyzed the number of fluorescence in situ hybridization (FISH) signals targeted for a whole chromosome 2 in cytokinesis-blocked binucleated TK6 cells and WTK-1 cells treated with colcemid and MMS, and concurrently detected DNA fragmentation by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Results revealed that DNA fragmentation occurred in 60% of all binucleated TK6 cells harboring colcemid-induced chromosome loss (30% of micronuclei and 30% of main nuclei). DNA fragmentation was observed in colcemid-induced micronuclei containing a whole chromosome but not in MMS-induced micronuclei containing chromosome fragments. In contrast, colcemid-induced nondisjunction had no effect on induction of DNA fragmentation, suggesting that DNA fragmentation was triggered by micronuclei containing a whole chromosome but not by micronuclei containing chromosome fragments or nondisjunction. In addition, the frequency of binucleated cells harboring chromosome loss with DNA fragmentation in micronuclei or main nuclei was higher in wild-type p53 TK6 cells than in mutated-p53 WTK-1 cells treated with colcemid. Taken together, these present and previous results suggest that colcemid-induced chromosome loss is caused by DNA fragmentation, which is triggered by a micronucleus with a whole chromosome and controlled by the p53-dependent pathway.
authors.affiliation: Drug Safety Research Laboratories, Astellas Pharma Inc., 2-1-6, Kashima, Yodogawa-ku, Osaka 532-8514, Japan; Laboratory of Radiation Biology, Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan.
authors.forename: Mika
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Drug Safety Research Laboratories, Astellas Pharma Inc., 2-1-6, Kashima, Yodogawa-ku, Osaka 532-8514, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Wakata
authors.affiliation: Drug Safety Research Laboratories, Astellas Pharma Inc., 2-1-6, Kashima, Yodogawa-ku, Osaka 532-8514, Japan.
authors.forename: Yoshinobu
authors.initials: Y
authors.lastname: Aoki
authors.affiliation: Drug Safety Research Laboratories, Astellas Pharma Inc., 2-1-6, Kashima, Yodogawa-ku, Osaka 532-8514, Japan.
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Miyamae
authors.affiliation: Laboratory of Radiation Biology, Department of Biological Science, Graduate School of Science, Osaka Prefecture University, 1-2, Gakuen-cho, Naka-ku, Sakai, Osaka 599-8570, Japan. Electronic address: kodama@riast.osakafu-u.ac.jp.
authors.forename: Seiji
authors.initials: S
authors.lastname: Kodama
mesh_terms: D000782:Aneuploidy; D002872:Chromosome Deletion; D002889:Chromosomes, Human, Pair 2; D053938:DNA Fragmentation / Q000187:drug effects*; D003703:Demecolcine / Q000494:pharmacology*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D020287:In Situ Nick-End Labeling; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D048629:Micronuclei, Chromosome-Defective / Q000187:drug effects*; D009153:Mutagens / Q000494:pharmacology*; D009630:Nondisjunction, Genetic; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
chemical_list: D009153:Mutagens; D016159:Tumor Suppressor Protein p53; D008741:Methyl Methanesulfonate; D003703:Demecolcine
keywords: Aneuploidy; Chromosome loss; DNA fragmentation; FISH; Micronucleus; TUNEL assay