Figure 6

Induction of p53-signaling by IFN-α and AZT in HTLV-1-infected cells. A. Intracellular phosphorylated p53 levels in ILT-Hod and ILT-#29 cells were evaluated by flow cytomertry 3 and 4 days after incubation, respectively, in the absence (black line) or presence of IFN-α (3000 IU/ml) alone (blue line), or IFN-α/AZT (10 μM) (red line). The closed histograms indicate cells stained with control antibody. B. ILT-Hod and ILT-#29 were treated with IFN-α and/or AZT for 4 days and mRNA expression of BAX (closed bar) and p21 (open bar) was evaluated by quantitative RT-PCR. Results are standardized with the copy number of GAPDH mRNA, and the relative values are indicated as means and SD of duplicate samples. *p < 0.05, **p ≤ 0.01. C. ILT-Hod and ILT-#29 cells were cultured with or without IFN-α/AZT in the presence or absence of a p53-inhibitor (Pifithrin-α p-Nitro Cyclic, 1 μM) for 3 days and 5 days, respectively, then the cells were analyzed for the cell cycle by flow cytometry following 7AAD-staining. The proportions of apoptotic cell fractions (pre G0/G1) were indicated below each histogram.