title: Impact of exogenous lysolipids on sensitive and multidrug resistant K562 cells: 1H NMR studies.
abstract: The ability of lysolipids to enter into a membrane bi-layer and disturb the membrane structure was used to study the behavior of K562 erythroleukemic cells, K562 wild type (K562wt) as well as the multidrug resistant cells K562adr. Both types of cells, when analyzed by proton NMR spectroscopy exhibit the high resolution signals assigned to so-called "mobile lipid" signals, which, in most cases, are located outside the lipid bi-layer as lipid droplets. In order to perform these studies, the K562wt and K562adr cells were treated for 48h with lysophosphatidylcholine oleoyl (LPC18), lysophosphatidylcholine palmitoyl (LPC16) and L-alpha-lysophosphatidyslerine (LPS). After evaluating toxicity of lysolipids, proton NMR of whole treated cells was used to analyze the mobile lipid content. Nile red staining and fluorescence microscopy were used to detect the presence of intracellular lipid droplets. Membrane lipid asymmetry perturbation was estimated by annexin V staining with use of flow cytometry. Using fluorescence spectroscopy the functioning of P-glycoprotein (P-gp) responsible for multidrug resistance was also evaluated after the treatment with lysolipids. Lysolipids were found to be more toxic for K562wt than for K562adr cells. LPS and LPC16 produced an increased of a mobile lipid NMR signal and amount of lipid droplets in K562wt cells only. LPC18, with the lowest toxicity, has shown more intense effects on NMR spectra with a large increase of lipid NMR signal without changes in lipid droplet staining. The functioning of the P-gp pump and membrane asymmetry were not modified by any of the lysolipids used.
authors.affiliation: LPBC-CSSB, UMR CNRS 7033, UFR SMBH, 74 rue Marcel Cachin, 93017 Bobigny, France.
authors.forename: Mounir
authors.initials: M
authors.lastname: Traïkia
authors.forename: Carole
authors.initials: C
authors.lastname: Marbeuf-Gueye
authors.forename: Edith
authors.initials: E
authors.lastname: Hantz
authors.forename: Laurence
authors.initials: L
authors.lastname: Le Moyec
mesh_terms: D049109:Cell Proliferation / Q000187:drug effects; D004351:Drug Resistance; D005434:Flow Cytometry; D005456:Fluorescent Dyes; D006801:Humans; D020128:Inhibitory Concentration 50; D020014:K562 Cells / Q000187:drug effects* / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000633:toxicity*; D008246:Lysophospholipids / Q000633:toxicity*; D009682:Magnetic Resonance Spectroscopy; D008563:Membrane Lipids / Q000378:metabolism*; D010078:Oxazines
chemical_list: D005456:Fluorescent Dyes; D008244:Lysophosphatidylcholines; D008246:Lysophospholipids; D008563:Membrane Lipids; D010078:Oxazines; C025059:lysophosphatidylserine; C006065:We 201; C082823:1-oleoyl lysophosphatidylcholine; C044808:nile red