The long-term goal of this proposal is to understand the chemistry of the key reactive intermediates that mediate the biological effects of mutagenic and carcinogenic nitrosamines and the effects of nitrosamine and reactive intermediate structure that impact their biological activity. Nitrosamines are a large class of structurally diverse carcinogens to which there is significant human exposure. Classically, the deleterious effects of nitrosamines have been ascribed to metabolic activation by P450 enzymes that yield unstable alpha-hydroxynitrosamines that decompose to diazoic acids. These yield diazonium ions and carbocations that alkylate DNA, ultimately producing mutations. This is well established for methyl and ethyl-substituted compounds, but in contrast the activity of more complex nitrosamines may be only partly or poorly described by the classical pathway. This proposal seeks to: a) delineate the non classical aqueous chemistry of more complex alpha-hydroxynitroamines; and b) to determine the extent of formation and biological implications, with respect to human polymerase interactions and human mutagenesis, of branched alkyl group adducts of DNA. There are 5 specific aims: 1) synthesis and study of the aqueous chemistry of alpha hydroxynitrosamines and related derivatives of N-nitrosomorpholine, nitrosonornicotine, and nitrosoanabasine; 2) quantitation of the formation of isopropyl adducts of A, G and T bases from reactions with DNA of isopropyl cations derived from the iso-propyl or n-propyl diazonium ions; 3) synthesis of isopropylated exocyclic oxygen and nitrogen DNA base phosphoramidites and incorporation into synthetic oligonucleotides containing adducts at defined positions; 4) analysis of coding and extension opposite the adducts by human DNA polymerases; and 5) determination of the frequency and spectrum of mutations in human fibroblasts arising from the adducted oligos, by means of the shuttle plasmid pLS189.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA052881-13
Application #
6512690
Study Section
Special Emphasis Panel (ZRG1-RAD (01))
Program Officer
Johnson, Ronald L
Project Start
1990-08-08
Project End
2006-03-31
Budget Start
2002-04-01
Budget End
2003-03-31
Support Year
13
Fiscal Year
2002
Total Cost
$391,554
Indirect Cost
Name
University of Maryland Balt CO Campus
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
City
Baltimore
State
MD
Country
United States
Zip Code
21250
Koissi, Niangoran; Fishbein, James C (2013) Trapping of a cross-link formed by a major purine adduct of a metabolite of the carcinogen N-nitrosomorpholine by inorganic and biological reductants. Chem Res Toxicol 26:732-40
Koissi, Niangoran; Shah, Niti H; Ginevan, Brandon et al. (2012) Lactone metabolite common to the carcinogens dioxane, diethylene glycol, and N-nitrosomorpholine: aqueous chemistry and failure to mediate liver carcinogenesis in the F344 rat. Chem Res Toxicol 25:1022-8
Pence, Matthew G; Blans, Patrick; Zink, Charles N et al. (2011) Bypass of Nýý-ethylguanine by human DNA polymerase ýý. DNA Repair (Amst) 10:56-64
Zink, Charles N; Soissons, Nicolas; Fishbein, James C (2010) Products of the direct reaction of the diazonium ion of a metabolite of the carcinogen N-nitrosomorpholine with purines of nucleosides and DNA. Chem Res Toxicol 23:1223-33
Holland, Ryan; Navamal, Mettachit; Velayutham, Murugesan et al. (2009) Hydrogen peroxide is a second messenger in phase 2 enzyme induction by cancer chemopreventive dithiolethiones. Chem Res Toxicol 22:1427-34
Pence, Matthew G; Blans, Patrick; Zink, Charles N et al. (2009) Lesion bypass of N2-ethylguanine by human DNA polymerase iota. J Biol Chem 284:1732-40
Upton, Dana C; Wang, Xueying; Blans, Patrick et al. (2006) Mutagenesis by exocyclic alkylamino purine adducts in Escherichia coli. Mutat Res 599:1-10
Zink, Charles N; Kim, Hyun-Joong; Fishbein, James C (2006) Synthesis and aqueous chemistry of alpha-acetoxy-N-nitrosomorpholine: reactive intermediates and products. J Org Chem 71:202-9
Perrino, Fred W; Harvey, Scott; Blans, Patrick et al. (2005) Polymerization past the N2-isopropylguanine and the N6-isopropyladenine DNA lesions with the translesion synthesis DNA polymerases eta and iota and the replicative DNA polymerase alpha. Chem Res Toxicol 18:1451-61
Blans, Patrick; Fishbein, James C (2004) Determinants of selectivity in alkylation of nucleosides and DNA by secondary diazonium ions: evidence for, and consequences of, a preassociation mechanism. Chem Res Toxicol 17:1531-9

Showing the most recent 10 out of 13 publications