Figure 4. Senolytic therapy with ABT-737 prevents IR-enhanced tumor growth. (A) Experimental schema: Ten week old C57Bl/6NCr mice (n = 10 per condition) were exposed to no irradiation (0 Gy) or 6Gyx5 thoracic IR. Mice were treated with ABT-737 (75 mg/kg/day) or vehicle for 5 days during week 4 and week 7. Nine days after drug discontinuation, 5 × 105 B16F0 cells were injected intravenously via the lateral tail vein. Lung tissue was collected 9 days after tumor inoculation. (B) SA-β-Galactosidase positive cells were counted in lung tissue collected at 8 weeks in mice that did not receive tumor injection. (C) Representative images and graph of lung tumor nodule counts. (D) Size of tumor foci in the lung, scale bar 80 μm, §: indicates p < 0.05 compared to 0 Gy, Vehicle. *: indicates p < 0.05 compared to 6Gyx5, Vehicle.