Low dose radiation, inflammation, cancer and chemoprevention

Figures & data

Figure 1. Effects of Ionizing Radiation on Tumor Formation.

Figure 2. Schematic Illustration of Radiation Mechanisms That Might Contribute to Breast Cancer Development. Endoplasmic Reticulum stress (ER stress). Reactive Oxygen Species (ROS). Genes altered (IRE1 (the ribonuclease inositol-requiring protein-1), XBP1 (X-Box-binging protein), CHOP (the transcription factor C/EBP homologous protein).

Table 1. Effects of n-3 PUFAs in animals exposed to radiation.

Test Subject	Radiation Dose (Gy)	Type of Cells	Effects	References
Mice	12 Gy of X-ray Irradiation	Intestine	Survival Rate increased by	Sun et al. (2014)
Human	0, 2 or 4 Gy of X-ray Irradiation	Colorectal Cancer cells	DHA and to a lesser extent by EPA found to increase cell death, apoptosis and peroxide production after RT in LS174T and to a lesser extent in HT-29	Cai et al. (2014)
Human	4 Gy X-ray exposure	3 different human colorectal adenocarcinoma cell lines	Omega-3 PUFAs could be a potential candidates as nutritional adjuvants to enhance the efficacy of human colorectal cancer radiotherapy	Benais-Pont et al. (2006)
Human	1.9, 3.8,or 7.6 J/cm^2 of solar-simulated radiation (SSR)	applied to 3 skin sites of test subjects	Photo-immunosuppression appeared less in the omega-3 PUFA group than in the control group	Pilkington et al. (2013)
Rat	0–10 Gy Gamma-rays (137Cs γ-source, 1.5 Gy/min)	astrocytoma cells incubated in medium supplemented with GLA (Gamma Linolenic Acid), EPA, DHA, or OA (Oleic Acid)	GLA, EPA and DHA supplementation before, during, and after radiation therapy could enhance the radiation-induced cytotoxicity of rat astrocytoma cells	Vartak et al. (1997)

Table 2. Mechanisms of n-3 PUFAs in different types of cells exposed to radiation.

Cell Specification	EPA/DHA, omega3	No of Days/hours Omega-3 Dose Given	Mechanism	References
Intestine cells	2.82 g of EPA and 3.09 g of DHA	7 days	Tumor Necrosis factors TNF-alpha and IL-6 normalized	Sun et al. (2014)
LS174T and HT-29 CRC cells	20 or 50 micro-mol/L EPA or DHA	4 h	LS174T was found more sensitive to RT than HT-29.	Cai et al. (2014)
LS174T, CO112 and Caco-2 cells	30 to 100 micro-mol/L of Omega-3 PUFAs	3 days	omega-3 PUFAs induced a dose-dependent additive decrease in cancer cell survival after irradiation	Benais-Pont et al. (2006)
Skin cells of nickel-allergic women, 22–60 y old, with phototype I or II	5 g Omega-3 PUFA–containing lipid (70% EPA plus 10% DHA)	3 months	Oral Omega-3 PUFAs appear to reduce photo- immunosuppression in human skin, providing additional support for their chemo-preventive role	Pilkington et al. (2013)
36B10 rat astrocytoma cell	15–45 micro-mol/L GLA, EPA, or DHA	24 h	While GLA and DHA produced a medium cell-killing effect, EPA was extremely cytotoxic	Vartak et al. (1997)

Sun M, Pang L, Ju X, Sun H, Yu J, Zhao H, Yao W, Wei M. 2014. Attenuating effects of omega-3 fatty acids (Omegaven) on irradiation-induced intestinal injury in mice. Food Chem Toxicol. 64:275–280.

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Cai F, Sorg O, Granci V, Lecumberri E, Miralbell R, Dupertuis YM, Pichard C. 2014. Interaction of ω-3 polyunsaturated fatty acids with radiation therapy in two different colorectal cancer cell lines. Clin Nutr. 33:164–170.

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Benais-Pont G, Dupertuis YM, Kossovsky MP, Nouet P, Allal AS, Buchegger F, Pichard C. 2006. ω-3 Polyunsaturated fatty acids and ionizing radiation: combined cytotoxicity on human colorectal adenocarcinoma cells. Nutrition. 22:931–939.

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Pilkington SM, Massey KA, Bennett SP, Al-Aasswad NM, Roshdy K, Gibbs NK, Friedmann PS, Nicolaou A, Rhodes LE. 2013. Randomized controlled trial of oral omega-3 PUFA in solar-simulated radiation-induced suppression of human cutaneous immune responses. Am J Clin Nutr. 97:646–652.

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Vartak S, Robbins ME, Spector AA. 1997. Polyunsaturated fatty acids increase the sensitivity of 36B10 rat astrocytoma cells to radiation-induced cell kill. Lipids. 32:283–292.

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