title: Characterization of covalently modified deoxyribonucleosides formed from dibenz[a,j]anthracene in primary cultures of mouse keratinocytes.
abstract: Identification of various deoxyribonucleoside adducts formed in primary cultures of mouse keratinocytes exposed to dibenz[a,j]anthracene (DB[a,j]A) is presented. A preliminary analysis of the DNA adducts formed from 7-methyldibenz[a,j]anthracene (7MeDB[a,j]A) also is presented. Cultures of keratinocytes obtained from dorsal skins of female SENCAR mice were exposed to 0.5 microgram of tritium-labeled hydrocarbons/mL of medium for 24 h. The total DNA binding was 2.23 +/- 0.54 and 5.28 +/- 0.97 pmol of hydrocarbon/mg of DNA for DB[a,j]A and 7MeDB[a,j]A, respectively. These binding values represented the radioactivity associated with the modified deoxyribonucleosides separated from the normal deoxyribonucleosides on Sephadex LH-20 columns following enzymatic digestion of isolated DNA. Treatment of keratinocytes with DB[a,j]A produced adduct peaks corresponding to marker adducts derived from trans addition of both deoxyguanosine as well as deoxyadenosine residues to the (+) enantiomer of the anti-diol epoxide where the deoxyadenosine adducts were predominant. In addition, DNA adduct peaks corresponding to markers of trans and cis addition, respectively, of deoxyguanosine and deoxyadenosine to the (+)-syn-diol epoxide were also noted in these chromatograms. A major DNA adduct in cells exposed to DB[a,j]A was tentatively identified as resulting from the addition of deoxyadenosine to DB[a,j]A-5,6-oxide. Several other later eluting DNA adduct peaks, not corresponding to any of the marker adducts, were also present in these chromatograms. In comparison, when cells were exposed to the more biologically potent 7-methyl analogue, at least 12 DNA adduct peaks were consistently observed in HPLC chromatograms.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Department of Carcinogenesis, University of Texas M.D. Anderson Cancer Center, Smithville 78957.
authors.forename: R V
authors.initials: RV
authors.lastname: Nair
authors.forename: R D
authors.initials: RD
authors.lastname: Gill
authors.forename: A N
authors.initials: AN
authors.lastname: Nettikumara
authors.forename: W
authors.initials: W
authors.lastname: Baer-Dubowska
authors.forename: C
authors.initials: C
authors.lastname: Cortez
authors.forename: R G
authors.initials: RG
authors.lastname: Harvey
authors.forename: J
authors.initials: J
authors.lastname: DiGiovanni
mesh_terms: D000818:Animals; D001551:Benz(a)Anthracenes / Q000378:metabolism*; D002417:Cattle; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000378:metabolism*; D018736:DNA Adducts; D003853:Deoxyribonucleosides / Q000378:metabolism; D005260:Female; D015603:Keratinocytes / Q000378:metabolism*; D051379:Mice
chemical_list: D001551:Benz(a)Anthracenes; D018736:DNA Adducts; D003853:Deoxyribonucleosides; C071159:dibenz(a,j)anthracene-DNA adduct; C041515:dibenzo(aj)anthracene; C071158:7-methyldibenz(a,j)anthracene; D004247:DNA