Fig. 2

DTX-P7 suppresses tumor growth of quiescent/slowly proliferating A549/CD133⁺ cells via degradation of DYRK1A and subsequent cell cycle reentry. a Volume of xenograft tumor mass. A549/CD133⁺ tumor-bearing mice were randomized into receive intraperitoneal injection of vehicle control, 15 mg/kg DTX-P7, 30 mg/kg DTX-P7 or 15 mg/kg DTX once a week for 4 weeks (n = 7 mice/group). Data are represented by mean ± SEM. Arrows indicate the treatments. b Tumor tissues were dissected and weighed when the animals were euthanized in 4 weeks post treatment. c A549/CD133⁺ mock-sorted (untreated) or sorted into PKH26^high and PKH26^low populations were incubated for 72 h with 10 μM DTX or 10 μM DTX-P7 followed by cell viability assay. d–e A549/CD133⁺ cells were treated with vehicle control, DTX-P7, DTX or 17-AAG for 48 h followed by cell cycle analyses by propidium iodide. Panel e represents three independent experiments. f A549/CD133⁺ cells were treated with 0, 15, 30 nM DTX-P7 or 15 nM DTX for 48 h followed by total cell lysate preparation and Western blotting analysis. β-actin was used as a loading control. g Total lysate preparation and Western blotting analysis of tumor tissues. β-actin was used as a loading control. h DYRK1A was reduced by ubiquitination. A549/CD133⁺ cells were transfected with HA-Ubiquitin followed by treatment with vehicle control or 30 nM DTX-P7 for 24 h. The lysates were immunoprecipitated using an anti-DYRK1A antibody, followed by immunoblotting with an anti-HA antibody under denaturing conditions. *p < 0.05, **p < 0.01, versus control group