Figure 2. Etoposide-induced mitochondrial biogenesis is ATM-dependent.

a. Activation of ATM and AMPK were determined by Western blotting using specific antibodies against phosphorylated ATM at Ser1981 and phosphorylated AMPK at Thr172. α-tubulin was used as loading controls. HeLa cells were treated with 10 µM etoposide for 16 hrs. b–c. HeLa cells transfected with ATM siRNA or non-specific siRNA (NS siRNA) were treated with etoposide for 16 hrs. The mtDNA content was determined by quantitative real-time PCR (b). Phosphorylated AMPK at Thr172 was monitored by Western blotting (c). d. ATM siRNA and NS siRNA HeLa cells were treated with etoposide for 16 hrs. RNA was then isolated and the NRF-1 mRNA level was determined using RT-PCR.