Analysis of 1H NMR-detectable mobile lipid domains for assessment of apoptosis induced by inhibitors of DNA synthesis and replication

Cell membrane rearrangements coincident with apoptosis may contribute to the increase in the ratio of methylene (CH2 at 1.3 ppm) to methyl (CH3 at 0.9 ppm) resonance signal intensity as observed by proton nuclear magnetic resonance (H-1 NMR). We studied CH2 and CH3 resonances in cultured cell lines treated with etoposide and fludarabine or bioflavonoid quercetin. Etoposide treatment (10 mu M, 18 h) resulted in 3.3 fold increase of the CH2/CH3 signal intensity ratio and 6.4 fold decrease in choline signal of MT4 cells. Incubation of Namalwa cells with fludarabine (3 mu M, 72 h) increased the CH2/CH3 signal intensity ratio by 2.4 fold and choline resonance intensity was unchanged. Quercetin treatment (30 mu M, 1.5 month) increased CH2/CH3 ratio by 2.1 fold. Necrotic cell death upon ethanol (20%) or DMSO (30%) treatment did not change the CH2/CH3 signal intensity ratio. H-1 NMR-based study of mobile lipid domains is sensitive for detection of early engagement into apoptosis. (C) 2004 International Federation for Cell Biology. Published by Elsevier Ltd. All rights reserved.