Current and Future Methodology for Quantitation and Site-Specific Mapping the Location of DNA Adducts.

Gunnar Boysen,Intawat Nookaew

doi:10.3390/toxics10020045

Gunnar Boysen, Intawat Nookaew

Open Access

https://doi.org/10.3390/toxics10020045

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Abstract

Formation of DNA adducts is a key event for a genotoxic mode of action, and their presence is often used as a surrogate for mutation and increased cancer risk. Interest in DNA adducts are twofold: first, to demonstrate exposure, and second, to link DNA adduct location to subsequent mutations or altered gene regulation. Methods have been established to quantitate DNA adducts with high chemical specificity and to visualize the location of DNA adducts, and elegant bio-analytical methods have been devised utilizing enzymes, various chemistries, and molecular biology methods. Traditionally, these highly specific methods cannot be combined, and the results are incomparable. Initially developed for single-molecule DNA sequencing, nanopore-type technologies are expected to enable simultaneous quantitation and location of DNA adducts across the genome. Herein, we briefly summarize the current methodologies for state-of-the-art quantitation of DNA adduct levels and mapping of DNA adducts and describe novel single-molecule DNA sequencing technologies to achieve both measures. Emerging technologies are expected to soon provide a comprehensive picture of the exposome and identify gene regions susceptible to DNA adduct formation.

Highlights

DNA is a very stable molecule for storing biological information, it is under relentless attack by reactive compounds of endogenous and exogenous origin that covalently bind to DNA, forming so called DNA adducts [1]
When the goal is to understand the exposome, mass spectrometry-based adductomics is the method of choice
Detection and quantitation of DNA adducts derived from a mixture of pollutants in the target tissue will unambiguously demonstrate, with high chemical specificity, that the subject has been exposed and that the toxicant has reached the tissue of concern

Summary

Introduction

DNA is a very stable molecule for storing biological information, it is under relentless attack by reactive compounds of endogenous and exogenous origin that covalently bind to DNA, forming so called DNA adducts [1]. The ability of a compound to form DNA adducts, directly or after metabolic activation, is considered a critical event in chemical carcinogenesis [11] and a key event for the genotoxic mode of action of toxicants [12,13]. The binding to DNA has been widely used as biomarker of exposure in molecular epidemiology studies to link exposure to adverse health outcomes [14,15,16]. Formation and stability of specific promutagenic DNA adducts has been established in vitro, in cell cultures, animal experiments, and molecular epidemiology studies [5,6,17]. Especially in mass spectrometry, allows for ‘omics’ type monitoring of DNA adducts, DNA adductomics, and is expected to provide unprecedented insight into the total exposome [18,19,20,21]

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Discussion

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