Abstract
In order to measure simultaneously replicating DNA synthesis (RDS) and unscheduled DNA synthesis (UDS) in rat hepatocytes responding to exposure to carcinogens, a new method, namely the “cell culture insert DNA retention (CDR)” method, was developed. All CDR procedures for cell culture, digestion of cytoplasm and retention of DNA were performed on membranes attached to cell culture containers. Four subgroups of primary cultures of hepatocytes prepared from rats were exposed to a genotoxic or non‐genotoxic carcinogen with or without 10 mM hydroxyurea and incubated for 4 h with 10 μCi/ml [3H]thymidine. The membranes were then processed for both liquid scintillation and autoradiography. Among seven tested chemicals, three genotoxic agents, 3,2′‐dimethyl‐4‐aminobiphenyl, 2‐acetylaminofluorene and diethylnitrosamine, and two non‐genotoxic carcinogens, nafenopin and phenobarbital, induced RDS within 4 h after the exposure, indicating that these carcinogenic agents induce cell proliferation in non‐proliferating rat hepatocytes prior to the emergence of genotoxic changes. Several indices were devised to characterize the genotoxicity of the tested chemicals. The induction patterns obtained showed a wide variation in the individual characteristics of carcinogen‐induced genotoxicity and mitogenicity in the early phase of initiation. This is the first report of simultaneous measurement, by using a combination of autoradiography and liquid scintillation, of UDS and RDS induced in rat hepatocytes. The described CDR approach will be useful for risk assessment and characterization of carcinogenic and tumor‐promoting agents.
Keywords: Risk assessment, Characterization of genotoxicity and mitogenicity, UDS, RDS, Cell proliferation
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REFERENCE
- 1.Miller , D. M. , Miller , J. A. , Hirono , I. , Sugimura , T. and Takayama , S. “ Naturally Occurring Carcinogens‐mutagens and Modulators of Carcinogens ,” pp. 399 ( 1979. ). Jpn. Scientific Societies Press, Tokyo and University Park Press; , Baltimore . [Google Scholar]
- 2.Brown , J. P.A review of the genetic effects of naturally occurring flavonoids, anthraquinones and related compounds . Mutat. Res ., 243 – 277 ( 1980. ). [DOI] [PubMed] [Google Scholar]
- 3.Gold , L. S. , Slone , T. H. , Stern , B. R. , Manley , N. B. and Ames , B. N.Rodent carcinogens: setting priorities . Science , 258 , 261 – 265 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 4.Hirono , I.Edible plants containing naturally occurring carcinogens in Japan . Jpn. J. Cancer Res ., 84 , 997 – 1006 ( 1993. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Hiatt , H. H. , Watson , J. D. and Winsten , J. A. “ Origins of Human Cancer ” ( 1977. ). Cold Spring Harbor Press; , Cold Spring Harbor , NY . [Google Scholar]
- 6.Ames , B. N.Identifying environmental chemicals causing mutations and cancer . Science , 204 , 587 – 593 ( 1979. ). [DOI] [PubMed] [Google Scholar]
- 7.Henderson , B. E. , Ross , K. R. and Pike , M. C.Toward the primary prevention of cancer . Science , 254 , 1131 – 1138 ( 1991. ). [DOI] [PubMed] [Google Scholar]
- 8.Hayashi , Y.Overview of genotoxic carcinogens and non‐genotoxic carcinogens . Exp. Toxicol. Pathol ., 44 , 465 – 472 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 9.McCann , J. and Ames , B. N.Detection of carcinogens as mutagens in the Salmonella/microsome test: assay of 300 chemicals: discussion . Proc. Natl. Acad. Sci. USA , 73 , 950 – 954 ( 1976. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 10.Tennant , R. W. , Margolin , B. H. , Shelby , M. D. , Zeiber , E. , Haseman , J. K. , Spalding , J. , Caspary , W. , Resenick , M. , Stasiewicz , S. , Anderson , B. and Minor , R.Prediction of chemical carcinogenicity in rodents from in vitro genetic toxicity assays . Science , 236 , 933 – 941 ( 1987. ). [DOI] [PubMed] [Google Scholar]
- 11.Williams , G. M. , Mori , H. and McQueen , C. A.Structure‐activity relationships in the rat hepatocyte DNA‐repair test for 300 chemicals . Mutat. Res ., 221 , 263 – 286 ( 1989. ). [DOI] [PubMed] [Google Scholar]
- 12.Bissel , D. M. , Hammaker , L. E. and Meyer , U. A.Parenchymal cells from adult rat liver in nonproliferating monolayer culture. 1. Functional studies . J. Cell Biol ., 59 , 722 – 734 ( 1973. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 13.Bonney , R. J.Adult liver parenchymal cells in primary culture: characteristics and cell recognition standards . In vitro , 10 , 130 – 142 ( 1973. ). [DOI] [PubMed] [Google Scholar]
- 14.Laishes , B. A. and Williams , G. M.Conditions affecting primary cell culture of functional adult rat hepatocytes. 1. The effect of insulin . In vitro , 12 , 521 – 532 ( 1976. ). [DOI] [PubMed] [Google Scholar]
- 15.Lin , R. C. S. P.Primary culture of normal adult rat liver cells which maintain stable urea cycle enzymes . Biochem. Biophys. Res. Commun ., 64 , 725 – 734 ( 1975. ). [DOI] [PubMed] [Google Scholar]
- 16.Michalopoulos , G. and Pitot , H. C.Primary culture of parenchymal liver cells on collagen membranes . Exp. Cell Res ., 72 , 5135 – 5139 ( 1975. ). [DOI] [PubMed] [Google Scholar]
- 17.Fautz , R. , Foster , R. , Hechengeger , C. M. A. , Hertner , T. , Hude , W. , Kaufmann , G. , Madle , H. , Madle , S. , Miltenburger , H. G. , Müller , L. , Pool‐Zobel , B. L. , Puri , E. C. , Schmezer , P. , Seeberg , A. H. , Strobel , R. and Suter , W.Report of a comparative study of DNA damage and repair assays in primary rat hepatocytes with five coded chemicals . Mutat. Res ., 260 , 281 – 294 ( 1991. ). [DOI] [PubMed] [Google Scholar]
- 18.Williams , G. M.Detection of chemical carcinogens by unscheduled DNA synthesis in rat liver primary cell cultures . Cancer Res ., 37 , 1845 – 1851 ( 1977. ). [PubMed] [Google Scholar]
- 19.Mori , H. , Kawai , K. , Ohbayashi , F. , Tokuro , K. , Yamazaki , M. , Hamasaki , T. and Williams , G.Genotoxicity of a variety of mycotoxins in the hepatocyte primary culture/DNA repair test using rat and mouse hepatocytes . Cancer Res ., 44 , 2918 – 2923 ( 1984. ). [PubMed] [Google Scholar]
- 20.Mori , H. , Sugie , S. , Hirono , I. , Yamada , K. , Niwa , H. and Ojika , M.Genotoxicity of ptaquiloside, a bracken carcinogen, in the hepatocyte primary culture/DNA‐repair test . Mutat. Res ., 143 , 75 – 78 ( 1985. ). [DOI] [PubMed] [Google Scholar]
- 21.Mori , H. , Mori , Y. , Sugie , S. , Yoshimi , N. , Takahashi , M. , Ni‐i , H. , Yamazaki , H. , Toyoshi , K. and Williams , G. M.Genotoxicity of a variety of azobenzene and aminoazo‐benzene compounds in the hepatocyte/DNA repair test and the Salmonella/mutagenicity test . Cancer Res ., 46 , 1654 – 1658 ( 1986. ). [PubMed] [Google Scholar]
- 22.Mori , H. , Yoshimi , N. , Kinouchi , T. and Ohnishi , Y.Genotoxicity of a variety of nitrosoarenes and other nitro compounds in DNA‐repair tests with rat and mouse hepatocytes . Mutat. Res ., 190 , 159 – 167 ( 1987. ). [DOI] [PubMed] [Google Scholar]
- 23.Mori , H. , Yoshimi , N. , Iwata , H. , Tanaka , T. , Kawai , K. and Sankawa , U.Additional survey on genotoxicity of natural anthraquinones in the hepatocyte primary culture/DNA repair assay . J. Toxicol. Sci ., 13 , 161 – 166 ( 1988. ). [DOI] [PubMed] [Google Scholar]
- 24.Yoshimi , N. , Sugie , S. , Iwata , H. , Niwa , K. , Mori , H. , Hashida , C. and Shimizu , H.The genotoxicity of variety of aniline derivatives in a DNA repair test with primary culture rat hepatocytes . Mutat. Res ., 206 , 183 – 191 ( 1988. ). [DOI] [PubMed] [Google Scholar]
- 25.Mori , H. , Yoshimi , N. , Sugie , S. , Iwata , H. , Kawai , K. , Mashizu , N. and Shimizu , H.Genotoxicity of epoxy resin hardeners in the hepatocyte primary culture/DNA repair test . Mutat. Res ., 204 , 683 – 688 ( 1988. ). [DOI] [PubMed] [Google Scholar]
- 26.Mori , H. , Sugie , S. , Yoshimi , N. , Iwata , H. , Nishikawa , A. , Matsukubo , K. , Shimizu , H. and Hirono , I.Genotoxicity of a variety of hydrazine derivatives in the hepatocyte primary culture/DNA repair test using rat and mouse hepatocytes . Jpn. J. Cancer Res ., 79 , 204 – 211 ( 1988. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 27.Butterworth , B. E. , Smith‐Oliver , T. , Earle , L. , Loury , D. J. , Doolittle , D. J. , Working , P. K. , Cattley , R. C. , Jirtle , R. , Michalpoulos , G. and Strom , S.Use of primary cultures of human hepatocytes in toxicology studies . Cancer Res ., 49 , 1075 – 1084 ( 1989. ). [PubMed] [Google Scholar]
- 28.Mori , H. , Sugie , S. , Okumura , A. , Hara , A. , Kinouchi , T. , Kataoka , K. and Ohnishi , Y.Genotoxicity of pyrene oxide and 1‐nitropyrene oxides in hepatocyte primary culture/DNA repair test . Mutat. Res ., 262 , 233 – 238 ( 1991. ). [DOI] [PubMed] [Google Scholar]
- 29.Sugie , S. , Yoshimi , N. , Okumura , A. , Tanaka , T. and Mori , H.Modifying effects of benzyl isothiocyanate and benzyl thiocyanate on DNA synthesis in primary cultures of rat hepatocytes . Carcinogenesis , 14 , 281 – 283 ( 1993. ). [DOI] [PubMed] [Google Scholar]
- 30.Martin , C. N. , McDermid , A. C. and Garner , R. C.Testing of known carcinogens and noncarcinogens for their ability to induce unscheduled DNA synthesis in HeLa cells . Cancer Res ., 38 , 2621 – 2627 ( 1978. ). [PubMed] [Google Scholar]
- 31.Tsutui , T. , Suzuki , N. , Maizumi , I. I. and Barrett , J. C.Characterization of an unscheduled DNA synthesis assay with Syrian hamster embryo‐cells . Mutat. Res ., 129 , 111 – 117 ( 1984. ). [DOI] [PubMed] [Google Scholar]
- 32.Wang , S. , Lai , C. and Wang , C.Inhibitory effect of geniposide on aflatoxin B1‐induced DNA repair synthesis in primary cultured rat hepatocytes . Cancer Lett ., 65 , 133 – 137 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 33.Cohen , S. M. and Ellwein , L. B.Genetic errors, cell proliferation, and carcinogenesis . Cancer Res ., 51 , 6493 – 6505 ( 1991. ). [PubMed] [Google Scholar]
- 34.Cohen , S. M. and Ellwein , L. B.Cell proliferation in carcinogenesis . Science , 249 , 1007 – 1011 ( 1990. ). [DOI] [PubMed] [Google Scholar]
- 35.Henderson , B. E. , Ross , R. and Bernstein , L.Estrogens as a cause of human cancer: The Richard and Hinda Rosenthal Foundation Award Lecture . Cancer Res ., 48 , 246 – 253 ( 1988. ). [PubMed] [Google Scholar]
- 36.Butterworth , B. E. , Slaga , T. J. , Farland , W. and McClain , M. “ Chemically Induced Cell Proliferation: Implications for Risk Assessment ,” p. 547 ( 1988. ). Wiley‐Liss; , New York . [Google Scholar]
- 37.Ames , B. N. , Shigenaga , M. K. and Gold , L. S.DNA lesions, inducible DNA repair, and cell division: three key factors in mutagenesis and carcinogenesis . Environ. Health Perspect ., 101 ( Suppl. 5 ), 35 – 44 ( 1993. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 38.Ames , B. N. and Gold , L. S.Chemical carcinogenesis: too many rodent carcinogens . Proc. Natl. Acad. Sci. USA , 87 , 7772 – 7776 ( 1990. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 39.Morley , C. G. D. and Kingdon , H. S.Use of 3H‐thymidine for measurement of DNA synthesis in rat liver: a warning . Anal. Biochem ., 45 , 298 – 305 ( 1972. ). [DOI] [PubMed] [Google Scholar]
- 40.Michalopoulos , G. , Houck , K. A. , Dolan , M. L. and Luetteke , N. C.Control of hepatocyte replication by two serum factors . Cancer Res ., 44 , 4414 – 4419 ( 1984. ). [PubMed] [Google Scholar]
- 41.Manjeshwar , S. , Rao , P. M. , Rajalakshhmi , S. and Sarma , D. S. R.Inhibition of DNA synthesis by phenobarbital in primary cultures of hepatocytes from normal rat liver and from hepatic nodules . Carcinogenesis , 13 , 2287 – 2291 ( 1992. ). [DOI] [PubMed] [Google Scholar]
- 42.Hsia , M. T. S. , Kreamer , B. L. and Dolara , P.A rapid and simple method to quantitate chemically induced unscheduled DNA synthesis in freshly isolated rat hepatocytes facilitated by DNA retention of membrane filters . Mutat. Res ., 122 , 177 – 185 ( 1983. ). [DOI] [PubMed] [Google Scholar]
- 43.Loud , A. V.A quantitative stereological description of the ultrastructure of normal rat liver parenchymal cells . J. Cell Biol ., 37 , 27 – 46 ( 1968. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 44.Furihata , C.Development and application of in vivo short‐term assay system for evaluation of environmental mutagens and carcinogens . Environ. Mutag. Res. Commun ., 11 , 1 – 12 ( 1989. ). [Google Scholar]
- 45.Ohsawa , K. , Furihata , C. , Mori , M. and Ikui , E.Ability of N‐methyl‐N'‐nitro‐N‐nitrosoguanidine, 4‐nitroquinoline 1‐oxide, dimethylnitrosamine, and NaCl to induce unscheduled DNA synthesis, stimulate replicative DNA synthesis, and produce DNA single‐strand breaks in pyloric mucosa of rat stomach . Mutat. Res ., 287 , 307 – 319 ( 1993. ). [DOI] [PubMed] [Google Scholar]
- 46.Sawada , N.Hepatocytes from old rats retain responsiveness of c‐myc expression to EGF in primay culture but do not enter S phase . Exp. Cell Res ., 181 , 584 – 588 ( 1989. ). [DOI] [PubMed] [Google Scholar]
- 47.Ikeda , T. , Sawada , N. , Fujinaga , K. , Minase , T. and Mori , M.c‐H‐ras gene is expressed at the G1 phase in primary cultures of hepatocytes . Exp. Cell Res ., 185 , 292 – 296 ( 1989. ). [DOI] [PubMed] [Google Scholar]
- 48.Kaufmann , W. K. , Rice , J. M. , MacKenzie , A. , Smith , G. J. , Wenk , M. L. , Devor , D. , Qaquish , B. F. and Kaufman , D. G.Proliferation of carcinogen‐damaged hepatocytes during cell‐cycle‐dependent initiation of hepatocarcinogenesis in the rat . Carcinogenesis , 12 , 1587 – 1593 ( 1991. ). [DOI] [PubMed] [Google Scholar]
- 49.Kokkinakis , D. M. and Subbarao , V.The significance of DNA damage, its repair and cell proliferation during carcinogen treatment in the initiation of pancreas cancer in the hamster model . Cancer Res ., 53 , 2790 – 2795 ( 1993. ). [PubMed] [Google Scholar]
- 50. St. Clair , W. H. , Dwarakanath , B. S. , Zhang , H. and Wheeler , K. T.Influence of proliferation on DNA repair rates in liver . Exp. Cell Res ., 197 , 323 – 325 ( 1991. ). [DOI] [PubMed] [Google Scholar]
- 51.Jutras , D. , Marion , M. and Denizeau , F.The effects of putative DNA repair inhibitors on DNA adduct levels and unscheduled DNA synthesis in rat hepatocytes exposed to 2‐acetylaminofluorene . Mutat. Res ., 216 , 35 – 42 ( 1989. ). [DOI] [PubMed] [Google Scholar]
- 52.LeDoux , S. , Thangada , M. , Bohr , V. A. and Wilson , G. L.Heterogeneous repair of methylnitrosourea‐induced alkali‐labile sites in different DNA sequences . Cancer Res ., 51 , 775 – 779 ( 1991. ). [PubMed] [Google Scholar]
- 53.Mironov , N. M. , Bleicher , F. and Martel‐Planche Montessano , R.Nonrandom distribution of O6‐methyl‐guanine in H‐ras gene sequence from DNA modified with N‐methyl‐N‐nitrosourea . Mutat. Res ., 288 , 197 – 205 ( 1993. ). [DOI] [PubMed] [Google Scholar]
- 54.El‐Deiry , W. S. , Tokino , T. , Velculescu , V. E. , Levy , D. B. , Parsons , R. , Trent , J. M. , Lin , D. , Mercer , W. E. , Kinzler , K. W. and Vogelstein , B.WAF1, a potential mediator of p53 tumor suppression . Cell , 75 , 817 – 825 ( 1993. ). [DOI] [PubMed] [Google Scholar]
- 55.Xiong , Y. , Hannon , G. J. , Zhang , H. , Casso , D. , Kobayashi , R. and Beach , D.p21 is a universal inhibitor of cyclin kinases . Nature , 366 , 701 – 704 ( 1993. ). [DOI] [PubMed] [Google Scholar]
- 56.Keler , T. , Barker , C. S. and Sorof , S.Specific growth stimulation by linoleic acid in hepatoma cell lines transfected with the target protein of a liver carcinogen . Proc. Natl. Acad. Sci. USA , 89 , 4830 – 4834 ( 1992. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 57.Khan , S. H. and Sorof , S.Preferential binding of growth inhibitory prostaglandins by the target protein of a carcinogen . Proc. Natl. Acad. Sci. USA , 87 , 9401 – 9405 ( 1990. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
- 58.Vinores , S. A. , Churey , J. J. , Haller , J. M. , Schnabel , S. J. , Custer , R. P. and Sorof , S.Normal liver chromatin contains a firmly bound and larger protein related to the principal cytosolic target polypeptide of a hepatic carcinogen . Proc. Natl. Acad. Sci. USA , 81 , 2092 – 2096 ( 1984. ). [DOI] [PMC free article] [PubMed] [Google Scholar]
