DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks
Charged-particle radiotherapy (CPRT) utilizing low and high linear energy transfer (low-/high-LET) ionizing radiation (IR) is a promising cancer treatment modality having unique physical energy deposition properties. CPRT enables focused delivery of a desired dose to the tumor, thus achieving a bett...
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-02-01
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| Series: | Molecules |
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| Online Access: | https://www.mdpi.com/1420-3049/27/5/1540 |
| _version_ | 1797474407116963840 |
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| author | Veronika Mladenova Emil Mladenov Martin Stuschke George Iliakis |
| author_facet | Veronika Mladenova Emil Mladenov Martin Stuschke George Iliakis |
| author_sort | Veronika Mladenova |
| collection | DOAJ |
| description | Charged-particle radiotherapy (CPRT) utilizing low and high linear energy transfer (low-/high-LET) ionizing radiation (IR) is a promising cancer treatment modality having unique physical energy deposition properties. CPRT enables focused delivery of a desired dose to the tumor, thus achieving a better tumor control and reduced normal tissue toxicity. It increases the overall radiation tolerance and the chances of survival for the patient. Further improvements in CPRT are expected from a better understanding of the mechanisms governing the biological effects of IR and their dependence on LET. There is increasing evidence that high-LET IR induces more complex and even clustered DNA double-strand breaks (DSBs) that are extremely consequential to cellular homeostasis, and which represent a considerable threat to genomic integrity. However, from the perspective of cancer management, the same DSB characteristics underpin the expected therapeutic benefit and are central to the rationale guiding current efforts for increased implementation of heavy ions (HI) in radiotherapy. Here, we review the specific cellular DNA damage responses (DDR) elicited by high-LET IR and compare them to those of low-LET IR. We emphasize differences in the forms of DSBs induced and their impact on DDR. Moreover, we analyze how the distinct initial forms of DSBs modulate the interplay between DSB repair pathways through the activation of DNA end resection. We postulate that at complex DSBs and DSB clusters, increased DNA end resection orchestrates an increased engagement of resection-dependent repair pathways. Furthermore, we summarize evidence that after exposure to high-LET IR, error-prone processes outcompete high fidelity homologous recombination (HR) through mechanisms that remain to be elucidated. Finally, we review the high-LET dependence of specific DDR-related post-translational modifications and the induction of apoptosis in cancer cells. We believe that in-depth characterization of the biological effects that are specific to high-LET IR will help to establish predictive and prognostic signatures for use in future individualized therapeutic strategies, and will enhance the prospects for the development of effective countermeasures for improved radiation protection during space travel. |
| first_indexed | 2024-03-09T20:30:35Z |
| format | Article |
| id | doaj.art-e68f8efbbbdb4fa28d888d7ba132c287 |
| institution | Directory Open Access Journal |
| issn | 1420-3049 |
| language | English |
| last_indexed | 2024-03-09T20:30:35Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Molecules |
| spelling | doaj.art-e68f8efbbbdb4fa28d888d7ba132c2872023-11-23T23:25:57ZengMDPI AGMolecules1420-30492022-02-01275154010.3390/molecules27051540DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin BreaksVeronika Mladenova0Emil Mladenov1Martin Stuschke2George Iliakis3Clinic and Polyclinic for Radiation Therapy, Medical School, University of Duisburg-Essen, 45122 Essen, GermanyClinic and Polyclinic for Radiation Therapy, Medical School, University of Duisburg-Essen, 45122 Essen, GermanyClinic and Polyclinic for Radiation Therapy, Medical School, University of Duisburg-Essen, 45122 Essen, GermanyClinic and Polyclinic for Radiation Therapy, Medical School, University of Duisburg-Essen, 45122 Essen, GermanyCharged-particle radiotherapy (CPRT) utilizing low and high linear energy transfer (low-/high-LET) ionizing radiation (IR) is a promising cancer treatment modality having unique physical energy deposition properties. CPRT enables focused delivery of a desired dose to the tumor, thus achieving a better tumor control and reduced normal tissue toxicity. It increases the overall radiation tolerance and the chances of survival for the patient. Further improvements in CPRT are expected from a better understanding of the mechanisms governing the biological effects of IR and their dependence on LET. There is increasing evidence that high-LET IR induces more complex and even clustered DNA double-strand breaks (DSBs) that are extremely consequential to cellular homeostasis, and which represent a considerable threat to genomic integrity. However, from the perspective of cancer management, the same DSB characteristics underpin the expected therapeutic benefit and are central to the rationale guiding current efforts for increased implementation of heavy ions (HI) in radiotherapy. Here, we review the specific cellular DNA damage responses (DDR) elicited by high-LET IR and compare them to those of low-LET IR. We emphasize differences in the forms of DSBs induced and their impact on DDR. Moreover, we analyze how the distinct initial forms of DSBs modulate the interplay between DSB repair pathways through the activation of DNA end resection. We postulate that at complex DSBs and DSB clusters, increased DNA end resection orchestrates an increased engagement of resection-dependent repair pathways. Furthermore, we summarize evidence that after exposure to high-LET IR, error-prone processes outcompete high fidelity homologous recombination (HR) through mechanisms that remain to be elucidated. Finally, we review the high-LET dependence of specific DDR-related post-translational modifications and the induction of apoptosis in cancer cells. We believe that in-depth characterization of the biological effects that are specific to high-LET IR will help to establish predictive and prognostic signatures for use in future individualized therapeutic strategies, and will enhance the prospects for the development of effective countermeasures for improved radiation protection during space travel.https://www.mdpi.com/1420-3049/27/5/1540ionizing radiationhigh-LET ionizing radiationcharged-particle radiotherapydouble-strand breaksDNA damage responsecomplex double-strand breaks |
| spellingShingle | Veronika Mladenova Emil Mladenov Martin Stuschke George Iliakis DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks Molecules ionizing radiation high-LET ionizing radiation charged-particle radiotherapy double-strand breaks DNA damage response complex double-strand breaks |
| title | DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks |
| title_full | DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks |
| title_fullStr | DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks |
| title_full_unstemmed | DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks |
| title_short | DNA Damage Clustering after Ionizing Radiation and Consequences in the Processing of Chromatin Breaks |
| title_sort | dna damage clustering after ionizing radiation and consequences in the processing of chromatin breaks |
| topic | ionizing radiation high-LET ionizing radiation charged-particle radiotherapy double-strand breaks DNA damage response complex double-strand breaks |
| url | https://www.mdpi.com/1420-3049/27/5/1540 |
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