title: Disruption of spindle checkpoint function in rats following 28 days of repeated administration of renal carcinogens.
abstract: We previously reported that 28-day exposure to hepatocarcinogens that facilitate cell proliferation specifically alters the expression of G1/S checkpoint-related genes and proteins, induces aberrant early expression of ubiquitin D (UBD) at the G2 phase, and increases apoptosis in the rat liver, indicating G1/S and spindle checkpoint dysfunction. The present study aimed to determine the time of onset of carcinogen-specific cell-cycle disruption after repeated administration of renal carcinogens for up to 28 days. Rats were orally administered the renal carcinogens nitrofurantoin (NFT), 1-amino-2,4-dibromoantraquinone (ADAQ), and 1,2,3-trichloropropane (TCP) or the non-carcinogenic renal toxicants 1-chloro-2-propanol, triamterene, and carboxin for 3, 7 or 28 days. Both immunohistochemical single-molecule analysis and real-time RT-PCR analysis revealed that carcinogen-specific expression changes were not observed after 28 days of administration. However, the renal carcinogens ADAQ and TCP specifically reduced the number of cells expressing phosphorylated-histone H3 at Ser10 in both UBD(+) cells and proliferating cells, suggestive of insufficient UBD expression at the M phase and early transition of proliferating cells from the M phase, without increasing apoptosis, after 28 days of administration. In contrast, NFT, which has marginal carcinogenic potential, did not induce such cellular responses. These results suggest that it may take 28 days to induce spindle checkpoint dysfunction by renal carcinogens; however, induction of apoptosis may not be essential. Thus, induction of spindle checkpoint dysfunction may be dependent on carcinogenic potential of carcinogen examined, and marginal carcinogens may not exert sufficient responses even after 28 days of administration.
authors.affiliation: Laboratory of Veterinary Pathology, Tokyo University of Agriculture and Technology.
authors.forename: Masayuki
authors.initials: M
authors.lastname: Kimura
authors.forename: Sayaka
authors.initials: S
authors.lastname: Mizukami
authors.forename: Yousuke
authors.initials: Y
authors.lastname: Watanabe
authors.forename: Yasuko
authors.initials: Y
authors.lastname: Hasegawa-Baba
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Onda
authors.forename: Toshinori
authors.initials: T
authors.lastname: Yoshida
authors.forename: Makoto
authors.initials: M
authors.lastname: Shibutani
mesh_terms: D000818:Animals; D000880:Anthraquinones / Q000008:administration & dosage* / Q000633:toxicity*; D001835:Body Weight / Q000187:drug effects; D002261:Carboxin / Q000008:administration & dosage / Q000633:toxicity; D049109:Cell Proliferation / Q000187:drug effects; D002728:Chlorohydrins / Q000008:administration & dosage / Q000633:toxicity; D006657:Histones / Q000378:metabolism; D007668:Kidney / Q000166:cytology* / Q000187:drug effects; D059566:M Phase Cell Cycle Checkpoints / Q000187:drug effects*; D008297:Male; D009582:Nitrofurantoin / Q000008:administration & dosage* / Q000633:toxicity*; D009929:Organ Size / Q000187:drug effects; D011407:Propane / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000633:toxicity; D011916:Rats, Inbred F344; D013997:Time Factors; D014223:Triamterene / Q000008:administration & dosage / Q000633:toxicity; D014452:Ubiquitins / Q000378:metabolism
chemical_list: D000880:Anthraquinones; D002728:Chlorohydrins; D006657:Histones; C109184:UBD protein, human; D014452:Ubiquitins; C009536:1,2,3-trichloropropane; D002261:Carboxin; D009582:Nitrofurantoin; C047777:1-amino-2,4-dibromoanthraquinone; D011407:Propane; D014223:Triamterene; C015750:1-chloro-2-propanol