Radiation-induced molecular modulations in thyroid cells cultured under iodine-deficiency

High doses of radiation induce harmful effects on the cells but the effects of low doses of radiations are still unclear. Besides radiation, there are worldwide two billion people suffering from iodine deficiency and the latter is known to have many consequences such as endemic goiter, growth retardation and it is a risk factor for thyroid cancer. As both external radiation and iodine deficiency induce harmful effects on thyroid cells separately and that there are little knowledge available about their combined effects, the current study was undertaken to understand the basic mechanisms of thyroid cancer risks after low dose exposure to external radiations under iodine deficiency. One potential mechanism by which external radiation and iodine deficiency would merge their harmful effects is the increase of ROS production at a level that becomes deleterious enough to trigger tumor initiation. This study shows that irradiation and iodine deficiency induce molecular changes in the thyroid cells that lead to the activation of pro-survival pathways and apoptosis escape, two mechanisms characteristic of cancer cells. Thus irradiation and iodine deficiency may be considered as risk factors for thyroid cancer initiation. These findings are important for radioprotection regulation.