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Hypoxia Reduces the Efficiency of Elisidepsin by Inhibiting Hydroxylation and Altering the Structure of Lipid Rafts
Department of Biophysics and Cell Biology, University of Debrecen, Nagyerdei krt. 98, Debrecen 4032, Hungary
Department of Biochemistry and Molecular Biology, University of Debrecen, Nagyerdei krt. 98, Debrecen 4032, Hungary
Cell Biology Department, PharmaMar, Avda de los Reyes 1, Pol. Ind. La Mina, Colmenar Viejo, Madrid 28770, Spain
MTA-DE Cell Biology and Signaling Research Group, University of Debrecen, Nagyerdei krt. 98, Debrecen 4032, Hungary
These authors contributed equally to this work.
* Author to whom correspondence should be addressed.
Received: 30 August 2013; in revised form: 26 October 2013 / Accepted: 5 November 2013 / Published: 2 December 2013
Abstract: The mechanism of action of elisidepsin (PM02734, Irvalec®) is assumed to involve membrane permeabilization via attacking lipid rafts and hydroxylated lipids. Here we investigate the role of hypoxia in the mechanism of action of elisidepsin. Culturing under hypoxic conditions increased the half-maximal inhibitory concentration and decreased the drug’s binding to almost all cell lines which was reversed by incubation of cells with 2-hydroxy palmitic acid. The expression of fatty acid 2-hydroxylase was strongly correlated with the efficiency of the drug and inversely correlated with the effect of hypoxia. Number and brightness analysis and fluorescence anisotropy experiments showed that hypoxia decreased the clustering of lipid rafts and altered the structure of the plasma membrane. Although the binding of elisidepsin to the membrane is non-cooperative, its membrane permeabilizing effect is characterized by a Hill coefficient of ~3.3. The latter finding is in agreement with elisidepsin-induced clusters of lipid raft-anchored GFP visualized by confocal microscopy. We propose that the concentration of elisidepsin needs to reach a critical level in the membrane above which elisidepsin induces the disruption of the cell membrane. Testing for tumor hypoxia or the density of hydroxylated lipids could be an interesting strategy to increase the efficiency of elisidepsin.
Keywords: elisidepsin; lipid rafts; hydroxylated lipids; fatty acid 2-hydroxylase; cooperative binding; membrane permeabilization
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MDPI and ACS Style
Király, A.; Váradi, T.; Hajdu, T.; Rühl, R.; Galmarini, C.M.; Szöllősi, J.; Nagy, P. Hypoxia Reduces the Efficiency of Elisidepsin by Inhibiting Hydroxylation and Altering the Structure of Lipid Rafts. Mar. Drugs 2013, 11, 4858-4875.
Király A, Váradi T, Hajdu T, Rühl R, Galmarini CM, Szöllősi J, Nagy P. Hypoxia Reduces the Efficiency of Elisidepsin by Inhibiting Hydroxylation and Altering the Structure of Lipid Rafts. Marine Drugs. 2013; 11(12):4858-4875.
Király, Anna; Váradi, Tímea; Hajdu, Tímea; Rühl, Ralph; Galmarini, Carlos M.; Szöllősi, János; Nagy, Peter. 2013. "Hypoxia Reduces the Efficiency of Elisidepsin by Inhibiting Hydroxylation and Altering the Structure of Lipid Rafts." Mar. Drugs 11, no. 12: 4858-4875.