Cell Survival and DNA Damage in Normal Prostate Cells Irradiated Out-of-Field.

Hdl Handle:
http://hdl.handle.net/10147/335975
Title:
Cell Survival and DNA Damage in Normal Prostate Cells Irradiated Out-of-Field.
Authors:
Shields, L
Affiliation:
a  Medical Physics Department, St. Luke's Hospital, Highfield Road, Rathgar, Dublin 6, Ireland;
Citation:
Cell Survival and DNA Damage in Normal Prostate Cells Irradiated Out-of-Field. 2014: Radiat. Res.
Journal:
Radiation research
Issue Date:
31-Oct-2014
URI:
http://hdl.handle.net/10147/335975
DOI:
10.1667/RR13777.1
PubMed ID:
25361398
Abstract:
Interest in out-of-field radiation dose has been increasing with the introduction of new techniques, such as volumetric modulated arc therapy (VMAT). These new techniques offer superior conformity of high-dose regions to the target compared to conventional techniques, however more normal tissue is exposed to low-dose radiation with VMAT. There is a potential increase in radiobiological effectiveness associated with lower energy photons delivered during VMAT as normal cells are exposed to a temporal change in incident photon energy spectrum. During VMAT deliveries, normal cells can be exposed to the primary radiation beam, as well as to transmission and scatter radiation. The impact of low-dose radiation, radiation-induced bystander effect and change in energy spectrum on normal cells are not well understood. The current study examined cell survival and DNA damage in normal prostate cells after exposure to out-of-field radiation both with and without the transfer of bystander factors. The effect of a change in energy spectrum out-of-field compared to in-field was also investigated. Prostate cancer (LNCaP) and normal prostate (PNT1A) cells were placed in-field and out-of-field, respectively, with the PNT1A cells being located 1 cm from the field edge when in-field cells were being irradiated with 2 Gy. Clonogenic and γ-H2AX assays were performed postirradiation to examine cell survival and DNA damage. The assays were repeated when bystander factors from the LNCaP cells were transferred to the PNT1A cells and also when the PNT1A cells were irradiated in-field to a different energy spectrum. An average out-of-field dose of 10.8 ± 4.2 cGy produced a significant reduction in colony volume and increase in the number of γ-H2AX foci/cell in the PNT1A cells compared to the sham-irradiated control cells. An adaptive response was observed in the PNT1A cells having first received a low out-of-field dose and then the bystander factors. The PNT1A cells showed a significant increase in γ-H2AX foci formation when 20 cGy irradiated in-field with a different energy spectrum compared to out-of-field. However, no significant difference in cell survival or colony volume was observed whether the PNT1A cells were irradiated in-field or out-of-field. Out-of-field radiation dose alone can have a damaging effect on the proliferation of PNT1A cells when a clinically relevant dose of 2 Gy is delivered in in-field. Out-of-field radiation with the transfer of bystander factors induces an adaptive response in the PNT1A cells.
ISSN:
1938-5404
Ethical Approval:
N/A

Full metadata record

DC FieldValue Language
dc.contributor.authorShields, Len_GB
dc.date.accessioned2014-11-21T14:48:35Z-
dc.date.available2014-11-21T14:48:35Z-
dc.date.issued2014-10-31-
dc.identifier.citationCell Survival and DNA Damage in Normal Prostate Cells Irradiated Out-of-Field. 2014: Radiat. Res.-
dc.identifier.issn1938-5404-
dc.identifier.pmid25361398-
dc.identifier.doi10.1667/RR13777.1-
dc.identifier.urihttp://hdl.handle.net/10147/335975-
dc.description.abstractInterest in out-of-field radiation dose has been increasing with the introduction of new techniques, such as volumetric modulated arc therapy (VMAT). These new techniques offer superior conformity of high-dose regions to the target compared to conventional techniques, however more normal tissue is exposed to low-dose radiation with VMAT. There is a potential increase in radiobiological effectiveness associated with lower energy photons delivered during VMAT as normal cells are exposed to a temporal change in incident photon energy spectrum. During VMAT deliveries, normal cells can be exposed to the primary radiation beam, as well as to transmission and scatter radiation. The impact of low-dose radiation, radiation-induced bystander effect and change in energy spectrum on normal cells are not well understood. The current study examined cell survival and DNA damage in normal prostate cells after exposure to out-of-field radiation both with and without the transfer of bystander factors. The effect of a change in energy spectrum out-of-field compared to in-field was also investigated. Prostate cancer (LNCaP) and normal prostate (PNT1A) cells were placed in-field and out-of-field, respectively, with the PNT1A cells being located 1 cm from the field edge when in-field cells were being irradiated with 2 Gy. Clonogenic and γ-H2AX assays were performed postirradiation to examine cell survival and DNA damage. The assays were repeated when bystander factors from the LNCaP cells were transferred to the PNT1A cells and also when the PNT1A cells were irradiated in-field to a different energy spectrum. An average out-of-field dose of 10.8 ± 4.2 cGy produced a significant reduction in colony volume and increase in the number of γ-H2AX foci/cell in the PNT1A cells compared to the sham-irradiated control cells. An adaptive response was observed in the PNT1A cells having first received a low out-of-field dose and then the bystander factors. The PNT1A cells showed a significant increase in γ-H2AX foci formation when 20 cGy irradiated in-field with a different energy spectrum compared to out-of-field. However, no significant difference in cell survival or colony volume was observed whether the PNT1A cells were irradiated in-field or out-of-field. Out-of-field radiation dose alone can have a damaging effect on the proliferation of PNT1A cells when a clinically relevant dose of 2 Gy is delivered in in-field. Out-of-field radiation with the transfer of bystander factors induces an adaptive response in the PNT1A cells.-
dc.languageENG-
dc.rightsArchived with thanks to Radiation researchen_GB
dc.titleCell Survival and DNA Damage in Normal Prostate Cells Irradiated Out-of-Field.en_GB
dc.contributor.departmenta  Medical Physics Department, St. Luke's Hospital, Highfield Road, Rathgar, Dublin 6, Ireland;en_GB
dc.identifier.journalRadiation research-
dc.type.qualificationlevelN/Aen
cr.approval.ethicalN/Aen
dc.description.fundingNo fundingen
dc.description.provinceLeinsteren
dc.description.peer-reviewpeer-reviewen

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