Linking somatic mutations in cancer to the electronic properties of DNA

Abstract

Oxidative stress, generated by both endogenous and exogenous agents, can cause DNA lesions that, if not repaired, accumulate as somatic mutations and can contribute to cancer initiation. Here, we explored this problem through the lens of DNA electronic properties, quantified by the vertical ionization potential (vIP) of nucleobase motifs, which reflects their susceptibility to oxidation. We analyzed genome-wide experimental data on oxidative DNA damage and found that the highest damage levels occur in regions with low vIP values, supporting a causal link between them. The analysis of cancer mutational signatures and their annotated aetiologies revealed strong anticorrelations between mutation frequency and vIP values, particularly in cancers driven by oxidative DNA damage, such as lung cancer. We further computed anticorrelations between vIP values and the frequencies of mutated motifs across coding and non-coding regions and across different mutation types, observing the strongest anticorrelations for silent mutations, consistent with their reduced selective pressure. Moreover, similar anticorrelations were observed for somatic mutations in cancer and normal tissues, as well as for germline mutations, suggesting that they arise from similar mutagenesis processes. This work clarifies how oxidative damage, DNA electronic properties and carcinogenesis are related and help identify genomic regions more prone to mutations.