AI Insight
This study investigates how oxygen levels affect DNA damage patterns in the three-dimensional genome structure after high linear energy transfer (LET) radiation exposure. Researchers developed a computational model showing that clustered double-strand breaks within specific genome regions correlate with the oxygen enhancement ratio across different radiation types. Their findings suggest that high-LET radiation creates dense ionization patterns that produce abundant DNA lesions in critical genomic locations, explaining why oxygen has less effect on enhancing radiation damage at high LET compared to low LET.
Why it matters
This research provides a mechanistic explanation for how radiation therapy effectiveness varies with oxygen levels and radiation type, which could inform treatment planning for tumors with low oxygen regions. Understanding these patterns may help optimize radiation therapy strategies, particularly for heavy ion radiotherapy used in cancer treatment.
arXiv:2503.21837v3 Announce Type: replace
Abstract: The variation of the oxygen enhancement ratio (OER) across linear energy transfer (LET) currently lacks a comprehensive mechanistic interpretation and a mechanistic model. Our earlier research revealed a significant correlation between the distribution of double-strand breaks (DSBs) within 3D genome and radiation-induced cell death, which offers valuable insights into the oxygen effect. We propose a model where the reaction of oxygen is represented as the probability of inducing DNA strand breaks. Then it is integrated into a track-structure Monte Carlo simulation to investigate the impact of oxygen on the distribution of DSBs within 3D genome. Using the parameters from our previous study, we calculate the OER values related to cell survival. Results show that the incidence ratios of clustered DSBs within a single topologically associating domain (TAD) (case 2) and within frequently interacting TADs (case 3) under aerobic and hypoxic conditions align with the trend in the OER of cell survival across LET. Our OER curves exhibit good correspondence with experimental data. This study provides a potentially mechanistic explanation for changes in OER across LET. High-LET irradiation leads to dense ionization events, resulting in an overabundance of lesions that readily induce case 2 and case 3, which have substantially higher probabilities of cell killing than other damage patterns. This may contribute to the main mechanism governing the variation of OER for high LET. Our study further underscores the importance of the DSB distribution within 3D genome in the context of radiation-induced cell death.