Mechanisms of enhanced cell killing at low doses: Implications for radiation risk
Our overall aim is to gather understanding of the mechanisms underlying low-dose hyperradiosensitivity (HRS) and induced radioresistance (IRR). There is now some direct evidence that this dose-dependent radiosensitivity phenomenon reflects changes in the amount, rate or type of DNA repair, rather than indirect mechanisms such as modulation of cell-cycle progression, growth characteristics or apoptosis. There is also indirect evidence that cell survival-related HRS/IRR in response to single doses might be a manifestation of the same underlying mechanism that determines the well-known adaptive response in the two-dose case, thus HRS can be removed by prior irradiation with both high- and low-LET radiations as well as a variety of other stress-inducing agents such as hydrogen peroxide and chemotherapeutic agents. Our goals in this project are therefore: (1) Identify which aspects of DNA repair (amount, rate and type) determine HRS/IRR, (2) Investigate the known link we have discovered between the extent of HRS/IRR and position in the cell cycle, focusing on changes in DNA structure and conformation which may modulate DNA repair, (3) Use the results from studies in (1) and (2) to distinguish, if necessary, between HRS/IRR and the adaptive response. The aim is to finally determine if these are separate or interlinked phenomena. Use the results from studies in (1), (2) and (3) to propose a mechanism to explain HRS/IRR.
- Research Organization:
- Gray Laboratory Cancer Research Trust, Mount Vernon Hospital, Northwood, United Kingdom (US)
- Sponsoring Organization:
- USDOE Office of Environmental Management (EM) (US)
- DOE Contract Number:
- FG07-99ER62878
- OSTI ID:
- 833481
- Report Number(s):
- EMSP-69981-2000; R&D Project: EMSP 69981; TRN: US200430%%1529
- Resource Relation:
- Other Information: PBD: 1 Jun 2000
- Country of Publication:
- United States
- Language:
- English
Similar Records
Transition in Survival From Low-Dose Hyper-Radiosensitivity to Increased Radioresistance Is Independent of Activation of ATM SER1981 Activity
ATM-Dependent Hyper-Radiosensitivity in Mammalian Cells Irradiated by Heavy Ions