Magnetic resonance spectroscopy and fluorescence microscopy to investigate mobile lipids in sensitive, resistant and reverting K562 cells and their membranes.
The erythroleukaemic K562 cell line and its adriamycin resistant counterpart were used to study resistance, its reversion and their consequences on the levels and localisation of lipids detected in proton nuclear magnetic resonance (NMR) spectra. On whole cells, the mobile lipids giving rise to a NMR signal were significantly decreased in the resistant cells when compared to the sensitive ones; these lipids recovered partially in the reverting cells. According to the spinlattice relaxation times (T1), the lipids detected appeared to be in a similar environment in sensitive and reverting cells. In membrane-enriched fractions, mobile lipid levels were not significantly different in the sensitive and reverting cell lines but decreased in resistant ones. Moreover, lipid droplets stained with a fluorescent Nile red lipophilic probe showed the presence of highly fluorescent particles in the samples in which NMR detected high levels of mobile lipids. These results suggest the participation of cytosolic lipid droplets in NMR signals in drug sensitive and reverting cells and open the question of the relative roles of these droplets and of the membrane lipids in the lipid metabolic pathways associated with drug resistance in cancer cells.
Le Moyec
L
L
Laboratoire CSSB, UFR SMBH, 74 rue Marcel Cachin, 93017 Bobigny, France. lemoyec@smbh.smbh.univ-paris13.fr
Kawakami
M
M
Leray
G
G
Larue
V
V
Briane
D
D
Hantz
E
E
De Certaines
J
J
D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D005227:Fatty Acids / Q000032:analysis; D005456:Fluorescent Dyes; D006801:Humans; D020014:K562 Cells; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000032:analysis*; D008856:Microscopy, Fluorescence; D010078:Oxazines; D014407:Tumor Cells, Cultured
D005227:Fatty Acids; D005456:Fluorescent Dyes; D008563:Membrane Lipids; D010078:Oxazines; C044808:nile red