PURPOSE: Radiotherapy is an effective cancer treatment, but a few patients suffer severe radiation toxicities in neighboring normal tissues. There is increasing evidence that the variable susceptibility to radiation toxicities is caused by the individual genetic predisposition, by subtle mutations, or polymorphisms in genes involved in cellular responses to ionizing radiation. Double-strand breaks (DSB) are the most deleterious form of radiation-induced DNA damage, and DSB repair deficiencies lead to pronounced radiosensitivity. Using a preclinical mouse model, the highly sensitive gammaH2AX-foci approach was tested to verify even subtle, genetically determined DSB repair deficiencies known to be associated with increased normal tissue radiosensitivity. EXPERIMENTAL DESIGN: By enumerating gammaH2AX-foci in blood lymphocytes and normal tissues (brain, lung, heart, and intestine), the induction and repair of DSBs after irradiation with therapeutic doses (0.1-2 Gy) was investigated in repair-proficient and repair-deficient mouse strains in vivo and blood samples irradiated ex vivo. RESULTS: gammaH2AX-foci analysis allowed to verify the different DSB repair deficiencies; even slight impairments caused by single polymorphisms were detected similarly in both blood lymphocytes and solid tissues, indicating that DSB repair measured in lymphocytes is valid for different and complex organs. Moreover, gammaH2AX-foci analysis of blood samples irradiated ex vivo was found to reflect repair kinetics measured in vivo and, thus, give reliable information about the individual DSB repair capacity. CONCLUSIONS: gammaH2AX analysis of blood and tissue samples allows to detect even minor genetically defined DSB repair deficiencies, affecting normal tissue radiosensitivity. Future studies will have to evaluate the clinical potential to identify patients more susceptible to radiation toxicities before radiotherapy.
PURPOSE: Radiotherapy is an effective cancer treatment, but a few patients suffer severe radiation toxicities in neighboring normal tissues. There is increasing evidence that the variable susceptibility to radiation toxicities is caused by the individual genetic predisposition, by subtle mutations, or polymorphisms in genes involved in cellular responses to ionizing radiation. Double-strand breaks (DSB) are the most deleterious form of radiation-induced DNA damage, and DSB repair deficiencies lead to pronounced radiosensitivity. Using a preclinical mouse model, the highly sensitive gammaH2AX-foci approach was tested to verify even subtle, genetically determined DSB repair deficiencies known to be associated with increased normal tissue radiosensitivity. EXPERIMENTAL DESIGN: By enumerating gammaH2AX-foci in blood lymphocytes and normal tissues (brain, lung, heart, and intestine), the induction and repair of DSBs after irradiation with therapeutic doses (0.1-2 Gy) was investigated in repair-proficient and repair-deficient mouse strains in vivo and blood samples irradiated ex vivo. RESULTS:gammaH2AX-foci analysis allowed to verify the different DSB repair deficiencies; even slight impairments caused by single polymorphisms were detected similarly in both blood lymphocytes and solid tissues, indicating that DSB repair measured in lymphocytes is valid for different and complex organs. Moreover, gammaH2AX-foci analysis of blood samples irradiated ex vivo was found to reflect repair kinetics measured in vivo and, thus, give reliable information about the individual DSB repair capacity. CONCLUSIONS:gammaH2AX analysis of blood and tissue samples allows to detect even minor genetically defined DSB repair deficiencies, affecting normal tissue radiosensitivity. Future studies will have to evaluate the clinical potential to identify patients more susceptible to radiation toxicities before radiotherapy.
Authors: M A Kuefner; S Grudzenski; J Hamann; S Achenbach; Michael Lell; K Anders; S A Schwab; L Häberle; M Löbrich; M Uder Journal: Eur Radiol Date: 2010-07-13 Impact factor: 5.315
Authors: Johanna Mirsch; Francesco Tommasino; Antonia Frohns; Sandro Conrad; Marco Durante; Michael Scholz; Thomas Friedrich; Markus Löbrich Journal: Proc Natl Acad Sci U S A Date: 2015-09-21 Impact factor: 11.205
Authors: Brandon J Baird; Jennifer S Dickey; Asako J Nakamura; Christophe E Redon; Palak Parekh; Yuri V Griko; Khaled Aziz; Alexandros G Georgakilas; William M Bonner; Olga A Martin Journal: Mutat Res Date: 2010-12-24 Impact factor: 2.433
Authors: Muhammad Jamal; Barbara H Rath; Eli S Williams; Kevin Camphausen; Philip J Tofilon Journal: Clin Cancer Res Date: 2010-10-29 Impact factor: 12.531
Authors: James C Knight; Caitríona Topping; Michael Mosley; Veerle Kersemans; Nadia Falzone; José M Fernández-Varea; Bart Cornelissen Journal: Eur J Nucl Med Mol Imaging Date: 2015-06-02 Impact factor: 9.236