Figure 5

bpV(HOpic) confers radio-protection by activating AKT signaling. (A) NIH-3T3 and Raw 264.7 cells were treated with bpV(HOpic) for indicated timepoints and AKT activation was assessed from whole cell lysate immunoblotting for pAKT and AKT protein levels. (B) Effect of bpV(HOpic) pretreatment on the status of AKT signaling in irradiated NIH-3T3 cells. Cells were treated with 100 nmol/L bpV(HOpic) and/or 2.5 μM Akt inhibitor MK-2206 1 h before 4 Gy irradiation. At 1 h post-irradiation, cells were harvested, and whole-cell lysates were subjected to immunoblotting, and densitometry analysis for pAKT/AKT levels (C) Pharmacological inhibition of AKT signaling reverses bpV(HOpic) conferred radioresistance in NIH-3T3 cells. Cell pretreated with AKT inhibitor, MK-2206, were subjected to IR-exposure upon bpV(Hopic) treatment. Cell counts were taken at indicative timepoints for each group. (D) Genetic inhibition of AKT signaling reverses bpV(HOpic) conferred radioresistance in NIH-3T3 cells. Cells expressing scrambled or AKT siRNA were treated with 100 nmol/L bpV(HOpic) before 4 Gy IR exposure, and cell counts were done at indicated timepionts. Inset immunoblot represents the status of AKT signaling at the time of IR exposure. Error bars are mean ± SD (n = 4) from two independent experiments. *p < 0.05; **p < 0.01.