FIGURE 1 from Temporary Knockdown of p53 During Focal Limb Irradiation Increases the Development of Sarcomas

Temporary reduction in p53 expression during irradiation increases sarcomagenesis. A, Schematic showing mice fed dox diet for 10 days to drive expression of shRNA to knockdown p53, irradiated with 30 or 40 Gy to the hind limb, returned to normal chow, and followed for sarcoma development and normal tissue injury in the radiation field. B, Kaplan–Meier curves show radiation-induced sarcoma-free survival of control and p53KD mice irradiated with 30 or 40 Gy to the hind limb. P value is from a log-rank test. C, Representative images of a H&E-stained radiation-induced sarcoma subtypes and table with the number of tumors from each subtype. D, Quantitation and representative IHC images of mouse muscle tissue from control and p53KD mice 4 hours after 30 Gy irradiation stained with antibodies recognizing cleaved caspase 3. The number of positive cells per tissue section is graphed. E, Representative flow cytometry dot plots of GFP+ muscle satellite cells isolated from unirradiated (left) and irradiated (right) limbs from control (top) or p53KD (bottom) mice. F, The relative ratio of GFP+ cells in the irradiated limb (30 Gy) over the unirradiated limb is graphed (±SEM). Each dot represents one mouse. P value is from a t test. G, Schematic showing that cells with functional p53 undergo apoptosis or cell-cycle arrest and repair after irradiation, while damaged cells with impaired p53 function are protected from cell death and persist. Figure generated using BioRender.