Fig. 8

CP as an intracellular potentiator of radiation responses in GB cells. The manipulation of CP expression in GB lines impacts both cell survival and activation of DNA repair/damage machinery (γH2AX), together with the production of reactive oxygen species with more superoxide anion, more SOD1 synthesis and more cellular Fe²⁺ when intracellular CP is present at high levels. These observations reemphasized also the role of Fenton's reaction tightly involved in the production of ROS by GB cells which might be one of the major link between intracellular CP levels and GB cell responses/survival to radiation. Hence, “GB prepared cells” under-expressing CP and “GB adapter cells” that naturally down regulate CP survive better to radiations thus providing a role for CP in the radio-resistance/radio-sensitiveness balance of GB cells