In the past few decades, significant progresses have been achieved in the realm of DNA methylation. Methylation of DNA at the C5 position of cytosine to give 5-methyl-2′-deoxycytidine (5-mdC), is one of the best-characterized epigenetic modifications and has been implicated in numerous biological processes. 5-hydroxymethyl-2'-deoxycytidine (5-hmdC) is also involved in various biological processes, including cellular differentiation and epigenetic regulation. Recently, N6-methyl-2′- deoxyadenosine (m6dA) was found to be present in human genome, and it has been demonstrated that m6dA plays important regulatory roles in gene expression, chromatin configuration, stress response and tumorigenesis. Here, we developed a targeted quantitative analysis method using hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) to analyze the contents of these epigenetic modifications in tissues samples collected from 82 matched pairs of tumor and adjacent tissues. In this work, 5-mdC, 5-hmdC and m6dA were unambiguously identified and accurately quantified by using stable isotope dilution strategy. The results suggested there was no significant difference of m6dA between all tumor tissues and tumor-adjacent tissues. However, the contents of 5-mdC and 5-hmdC were markedly lower in genomic DNA of tumor tissues than tumor-adjacent tissues. We performed statistical analysis to evaluate the correlation of m6dA, 5-mdC and 5-hmdC in genomic DNA between tumor types. Furthermore, ROC analysis was performed and we found that m6dA was highly effective in the detection of lung cancer and pancreatic cancer. And 5-hmdC was appropriate for the detection of gastric cancer, hepatic cancer, esophagus cancer and breast cancer. These results may stimulate future investigations about the regulatory roles of these epigenetic modifications in the development of cancers.

Quantification of 5-methyl-2′-deoxycytidine, 5-hydroxymethyl-2′-deoxycytidine and N6-methyl-2′-deoxyadenosine in genomic DNA from cancer tissues by HILIC-MS/MS

Fall 2022 abstracts, posters, and presentations will launch in mid-September.

ACS Fall 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.