Influence of chronic low-dose/dose-rate high-LET irradiation from radium-226 in a human colorectal carcinoma cell line
- Radiation Sciences Program, School of Graduate and Postdoctoral Studies, McMaster University, Hamilton, ON (Canada)
- Department of Biology, McMaster University, Hamilton, ON (Canada)
Purpose: To evaluate potential damages of chronic environmentally relevant low-dose/dose-rate high-LET irradiation from a naturally occurring alpha-emitting radionuclide (radium-226, {sup 226}Ra) on a human colorectal carcinoma HCT116 p53{sup +/+} cell line. Methods: Clonogenic survival assays and mitochondrial membrane potential (MMP) measurement with a sensitive fluorescent MMP probe JC-1 were performed in HCT116 p53{sup +/+} cells chronically exposure to low doses/dose rates of {sup 226}Ra with high-LET. Comparisons were made with the human non-transformed keratinocyte HaCaT cell line and acute low-dose direct low-LET gamma radiation. Results and conclusion: The chronic low-dose/dose-rate alpha radiation (CLD/DRAR) did not reduce the clonogenic survival of HCT116 p53{sup +/+} cells over the period of 70 days of exposure. Only one significant reduction in the HCT116 p53{sup +/+} cells’ clonogenic survival was when cells were grown with 10,000 mBq/mL {sup 226}Ra for 40 days and progeny cells were clonogenically assessed in the presence of 10,000 mBq/mL {sup 226}Ra. The cumulative doses that cells received during this period ranged from 0.05 to 46.2 mGy. The mitochondrial membrane potential (MMP) dropped initially in both HCT116 p53{sup +/+} and HaCaT cells in response to CLD/DRAR. The MMP in HCT116 p53{sup +/+} cells recovered more quickly at all dose points than and that in HaCaT cells until the end of the exposure period. The highest dose rate of 0.66 mGy/day depolarized the HaCaT's mitochondria more consistently during the exposure period. The faster recovery status of the MMP in HCT116 p53{sup +/+} cells than that in HaCaT cells was also observed after exposure to acute low-dose gamma rays. Overall, it was found that CLD/DRAR had little impact on the MMP of human colorectal cancer and keratinocyte cell lines. - Highlights: • Human colorectal carcinoma HCT116 p53{sup +/+} and keratinocyte HaCaT cells were exposed to chronic low-dose/dose-rate alpha radiation (CLD/DRAR). • Unlike the HaCaT cells, HCT116 p53{sup +/+} cells’ clonogenic survival and mitochondrial membrane potential (MMP) changed little upon CLD/DRAR. • Upon the mitochondrial membrane depolarization response induced by CLD/DRAR, HaCaT cells were more sensitive than HCT116 p53{sup +/+}. • Gamma radiation depolarized the mitochondria of both HaCaT and HCT116 p53{sup +/+} in a dose-dependent manner. • The MMP in HCT116 p53{sup +/+} could recover more quickly than that in HaCaT cells after an acute low-dose gamma irradiation challenge.
- OSTI ID:
- 22708017
- Journal Information:
- Environmental Research, Vol. 156; Other Information: Copyright (c) 2017 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0013-9351
- Country of Publication:
- United States
- Language:
- English
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