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. 2021 Mar 2;94(1119):20201191. doi: 10.1259/bjr.20201191

Figure 4.

Figure 4.

PI3K inhibition enhances radiotherapy treatment in 2D and 3D OAC models. (a) Cells were treated with GDC-0941 or vehicle control for 18 h and exposed to 2 Gy irradiation. The effect of GDC-0941 as a single agent and in combination with 2 Gy irradiation was assessed using the clonogenic assay. The surviving fraction was calculated relative to the 0 Gy DMSO control. (b–d) OE33, OE19, and SK-GT-4 spheroid models were generated as noted in Methods and materials and treated with 1 µM GDC-0941 or DMSO for 21 days in combination with a total of 5 × 2 Gy irradiation fractions or mock irradiated for the first 5 days. Spheroids were imaged using the GelCount instrument (Oxford Optronix), and spheroid size determined using ImageJ (NIH). Spheroid area is shown relative to day 0. Error bars represent mean ± SEM. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. (e) Schematic of the effect of GDC-0941 treatment of the PI3K-AKT signalling pathway. DMSO, dimethyl sulfoxide; SEM, standard error of the mean.