PI3K inhibition induced by Ly-294002 decreases the telomerase activity (Fig. 4) and dephosphorylates AKT in both sham-irradiated CB193 and T98G, suggesting that telomerase activity could be regulated by PI3K and AKT phosphorylation in glioblastomas, as in many cell types (47,49). Here, AKT1 is linked to glioblastoma.