phosphorus-radioisotopes and 4-hydroxy-2-nonenal

Exocyclic etheno-DNA adducts are formed by the reaction of lipid peroxidation products, such as 4-hydroxy-2-nonenal (HNE) with DNA bases to yield 1,N (6)-etheno-2'-deoxyadenosine (εdA), 3,-N (4)-etheno-2'-deoxycytidine (εdC), and etheno-2'-deoxyguanosine. These adducts act as a driving force for many human malignancies and are elevated in the organs of cancer-prone patients suffering from chronic inflammation and infections. Here, we describe the ultrasensitive and specific techniques for the detection of εdA and εdC in tissue and white blood cell (WBC) DNA. This approach is based on -combined immunopurification by monoclonal antibodies and (32)P-postlabeling analysis. The detection limit is about five adducts per 10(10) parent nucleotides, requiring 5-10 μg of DNA. In addition, we describe techniques for immunohistochemical detection of εdA and εdC in tissue biopsies, and the approaches for the -analysis of εdA and εdC excreted in urine. The utility of these detection methods for human studies is based on: (1) high sensitivity and specificity, (2) low amounts of DNA required, (3) capability to detect "background" levels of etheno-DNA adducts in biopsies, WBC, and urine samples of healthy subjects, and (4) reliable monitoring of the disease-related increase of these substances in patients.The described methods are useful in diagnosis and monitoring of chronic degenerative diseases, including cancer, atherosclerosis, and neurodegenerative disorders.

Topics: Aldehydes; Animals; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; DNA; DNA Adducts; Fluorescence; Humans; Hydrolysis; Immunohistochemistry; Isotope Labeling; Leukocytes; Liver; Organ Specificity; Phosphorus Radioisotopes; Rats; Xenograft Model Antitumor Assays

The tumorigenicity of chloral hydrate (CH), trichloroacetic acid (TCA), trichloroethanol (TCE), malondialdehyde (MDA), crotonaldehyde, acrolein, and 4-hydroxy-2-nonenal (HNE) was tested in the B6C3F(1) neonatal mouse. Mice were administered i.p. injections of CH (1000, 2000, 2500, and 5000 nmol per animal), TCA (1000 and 2000 nmol), TCE (1000 and 2000 nmol), MDA (1500 and 3000 nmol), crotonaldehyde (1500 and 3000 nmol), acrolein (75 and 150 nmol), and HNE (750 and 1500 nmol) at 8 and 15 days of age. At 12 months, only male mice treated with the positive control chemicals, 4-aminobiphenyl (500 and 1000 nmol) and benzo[a]pyrene (150 and 300 nmol), had incidences of tumors in the liver significantly higher than the solvent control. Additional male mice were dosed as described above and their livers were excised at 24, 48 h, and 7 days after the final dose. Liver DNA was isolated and analyzed by 32P-postlabeling/high-performance liquid chromatography (HPLC) and HPLC/electrochemical detection for MDA-derived adduct (M(1)G) and 8-oxo-2'-deoxyguanosine (8-OHdG) formation, respectively. At 24 and 48 h after the final dose, CH- and TCA-treated mice exhibited significantly higher M(1)G levels than the controls. 8-OHdG formation was also induced by CH, TCA, and MDA. These results suggest that under these experimental conditions the B6C3F(1) neonatal mouse is not sensitive to carcinogens that induce an increase in endogenous DNA adduct formation through lipid peroxidation or oxidative stress.

Topics: Acrolein; Aldehydes; Animals; Animals, Newborn; Carcinogenicity Tests; Carcinogens; Chloral Hydrate; Chromatography, High Pressure Liquid; Crosses, Genetic; DNA; DNA Adducts; Electrochemistry; Ethylene Chlorohydrin; Female; Lipid Peroxidation; Liver; Liver Neoplasms, Experimental; Male; Malondialdehyde; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Microsomes, Liver; Phosphorus Radioisotopes; Trichloroacetic Acid

A (32)P-postlabeling method was developed for the sensitive detection of 1,N(2)-propanodeoxyguanosine adducts of the lipid peroxidation product trans-4-hydroxy-2-nonenal in vivo. The method development was based on the chemically synthesized HNE-1, N(2)-propanodeoxyguanosine adduct standard, which was characterized by NMR and mass spectra. The adducts were enriched by nuclease P1. They were subsequently reacted with [gamma-(32)P]ATP to give the respective 3'-5'-bisphosphates, which were two-directionally separated on PEI-cellulose TLC and quantitated by autoradiography. The medium labeling efficiency for the mixture of the two pairs of diastereomers was 27%, and the recovery of spiked amounts of adduct standard in the enzymatical procedure was about 80%. The method is applicable for the separation and quantitation of HNE-dGp-propano adducts in vivo. It was applied to DNA from colon and brain tissue of untreated Fischer 344 rats and humans. The determination of the limit of quantitation in DNA from rat colon by spiking of adduct standard revealed a sensitivity of <21 adducts/10(9) nucleotides. The analytical quantitation of 4-HNE-dGp-propano adducts resulted in adduct-levels per 10(9) normal nucleotides +/- the standard deviation of 223.32 +/- 79.84 in rat colon tissue, 90.37 +/- 11.94 in rat brain tissue, 378.44 +/- 52.42 in human colon tissue, and 185.15 +/- 6.48 in human brain tissue. The results clearly demonstrate the applicability of this method for the sensitive detection of endogenously formed 1,N(2)-propanodeoxyguanosine adducts of trans-4-hydroxy-2-nonenal, a specific marker for the lipid peroxidation process.

Topics: Adult; Aldehydes; Animals; Autoradiography; Biomarkers; Brain; Brain Chemistry; Chromatography, Thin Layer; Colon; Cross-Linking Reagents; Deoxyguanosine; DNA Adducts; Drug Stability; Female; Humans; Isotope Labeling; Lipid Peroxidation; Nucleotides; Phosphorus Radioisotopes; Rats; Rats, Inbred F344; Reference Standards; Sensitivity and Specificity; Single-Strand Specific DNA and RNA Endonucleases

4-Hydroxy-2-nonenal (HNE), a major electrophilic byproduct of lipid peroxidation, is mutagenic and cytotoxic. The two pairs of HNE-derived diastereomeric 1,N2-propanodeoxyguanosine 3'-monophosphate adducts were synthesized from reaction of HNE with 2'-deoxyguanosine 3'-monophosphate. After HPLC separation, these adducts were characterized by UV-visible absorption and negative ion electrospray ionization MS/MS analysis. To further characterize the structures, these adducts were dephosphorylated to the corresponding HNE-modified deoxyguanosine adducts and their HPLC retention times and UV spectra were compared with those of the synthetic standards prepared from reaction of HNE with 2'-deoxyguanosine. Separation of these adducts by 32P-postlabeling/HPLC was developed. Reaction of HNE with calf thymus DNA resulted in only one pair of diastereomeric adducts, with one adduct predominantly formed with a modification level of 1.2 +/- 0.5 adducts/10(7) nucleotides.

Topics: Aldehydes; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Cysteine Proteinase Inhibitors; Deoxyguanosine; DNA Adducts; Isotope Labeling; Magnetic Resonance Imaging; Molecular Conformation; Mutagens; Phosphorus Radioisotopes; Spectrophotometry, Ultraviolet; Stereoisomerism