Telomerase activity is regulated at the level of transcription by a PI3K-dependent pathway in HTLV-I cell lines. (A) 1185 cells were treated with LY29 (10 μM), AKT II (20 μM), LY29 (10 μM)/AKT II (20 μM), or DMSO (solvent control) for 4 hours, followed by analysis of hTERT RNA expression by quantitative real-time PCR. GAPDH expression was used as a control. The expression level in 1185 cells treated with DMSO was defined as 1.0. Results are representative of 3 independent experiments and standard deviations are indicated by error bars. (B-D) 1185 cells were treated with LY29 (10 μM), AKT II (20 μM), LY29/AKT II (10 μM/20 μM), or DMSO (solvent control) for 48 hours, followed by TRAP analysis for telomerase activity (B), FACS analysis for cell cycle (C), or FACS analysis for apoptosis (D). TPGs were calculated as the percent-age of activity compared with DMSO control (100%). (E) 1185 cells were grown with or without IL-2 for 4 hours followed by Western blot analysis. Nuclear extracts were probed with anti–NF-κB RelA/p65, and cytoplasmic extracts with anti–IκB-α.