DNA Adductomics by Mass Tag Prelabeling

DNA adducts are damaged nucleotides in DNA as a consequence of its exposure to genotoxic agents or conditions. Measurement of multiple DNA adducts in a single procedure is referred to as “DNA adductomics”. In the leading analytical technique for this purpose, typically the following sequence of steps takes place starting with a biosample: 

- Isolate the DNA

- Digest it to deoxynucleosides enzymatically

- Remove the enzymes and inject into a UPLC-tandem mass spectrometer using CID conditions that release the sugar as a neutral

- Observe peaks for adducts as protonated nucleobases

While this method is highly successful as has been reviewed, it has some shortcomings, mainly: 

- Adduct sensitivity can vary widely for different adducts

- Though useful for bulky adducts, simultaneous detection of polar adducts is limited since they tend to elute in the early noise-intense region of reversed-phase liquid chromatography, much before most bulky adducts

P-postlabeling is a technique that has been widely employed for many years and can provide very high sensitivity. Its major disadvantages are that the yield of the labeling reaction is adduct dependent; it is difficult to incorporate internal standards, and it is not easy to establish the identity of a radioactive adduct spot.

 

 

Northeastern University researchers introduced a new technique for DNA adductomics they refer to as “Mass Tag Pre-labeling”. This name was selected since this method shares the feature of labeling with 32P-postlabeling. Also, there are two contrasts: labeling in this technique is done with a mass tag rather than a radiolabel, and the labeling is done prior to enzymatic digestion of the DNA to nucleotides. 

 

 

- Other mass spectrometry techniques only detect polar or nonpolar adducts at once

- Radiolabeling is nonspecific

- There is nowhere in the world currently where the people can send a sample of blood for a comprehensive DNA adductomics test

 

 

- Can be used in cell culture, animal, and clinical trials initially

- General use in clinical diagnostics as a cancer prevention test in the longer term

 

 

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