TPEN Induces Apoptosis Independently of Zinc Chelator Activity in a Model of Acute Lymphoblastic Leukemia and Ex Vivo Acute Leukemia Cells through Oxidative Stress and Mitochondria Caspase-3- and AIF-Dependent Pathways

Figure 1

TPEN induces chromatin condensation and DNA fragmentation in Jurkat cells in a concentration-dependent fashion. Representative fluorescent photomicrography showing untreated (−TPEN) cells with normal nuclei (asterisk), or treated cells (+TPEN, 3 μM) with condensed chromatin (arrows, stage I nuclei morphology) and DNA fragmentation (arrowheads, stage II nuclei morphology) analyzed by either AO/EB ((a), (b)) (ex. 450–490 nm, em. 515 nm), Hoechst staining ((a′), (b′)) (ex. 354 nm, em. 442 nm), or merge image ((a′′), (b′′)). (c) The percentage of positive AO/EB/Hoechst staining of Jurkat cells treated with increasing TPEN concentrations with normal, stage I, and stage II nuclei morphology are expressed as a mean percentage ± S.D. from three independent experiments. Magnification ((a), (b)) 800x. Photomicrographs shown in (a)-(b) and Figures 2(a), 4(a)–4(f), 6(a)–6(f) and 7(a)–7(d) were taken using a Zeiss (Axiostart 50) microscope equipped with a Canon PowerShot G5 digital camera. Fiji (Fiji-win32) image processing package was used for composite image ((a′′)-(b′′)).