title: Hyperfluidization-coupled membrane microdomain reorganization is linked to activation of the heat shock response in a murine melanoma cell line.
abstract: Targeting of the Hsp function in tumor cells is currently being assessed as potential anticancer therapy. An improved understanding of the molecular signals that trigger or attenuate the stress protein response is essential for advances to be made in this field. The present study provides evidence that the membrane fluidizer benzyl alcohol (BA), a documented nondenaturant, acts as a chaperone inducer in B16(F10) melanoma cells. It is demonstrated that this effect relies basically on heat shock transcription factor 1 (HSF1) activation. Under the conditions tested, the BA-induced Hsp response involves the up-regulation of a subset of hsp genes. It is shown that the same level of membrane fluidization (estimated in the core membrane region) attained with the closely analogous phenethyl alcohol (PhA) does not generate a stress protein signal. BA, at a concentration that activates heat shock genes, exerts a profound effect on the melting of raft-like cholesterol-sphingomyelin domains in vitro, whereas PhA, at a concentration equipotent with BA in membrane fluidization, has no such effect. Furthermore, through the in vivo labeling of melanoma cells with a fluorescein labeled probe that inserts into the cholesterol-rich membrane domains [fluorescein ester of polyethylene glycol-derivatized cholesterol (fPEG-Chol)], we found that, similarly to heat stress per se, BA, but not PhA, initiates profound alterations in the plasma membrane microdomain structure. We suggest that, apart from membrane hyperfluidization in the deep hydrophobic region, a distinct reorganization of cholesterol-rich microdomains may also be required for the generation and transmission of stress signals to activate hsp genes.
authors.affiliation: Institute of Biochemistry, Biological Research Center, Hungarian Academy of Sciences, P.O. Box 521, H-6701, Szeged, Hungary.
authors.forename: Eniko
authors.initials: E
authors.lastname: Nagy
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Balogi
authors.forename: Imre
authors.initials: I
authors.lastname: Gombos
authors.forename: Malin
authors.initials: M
authors.lastname: Akerfelt
authors.forename: Anders
authors.initials: A
authors.lastname: Björkbom
authors.forename: Gábor
authors.initials: G
authors.lastname: Balogh
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Török
authors.forename: Andriy
authors.initials: A
authors.lastname: Maslyanko
authors.forename: Anna
authors.initials: A
authors.lastname: Fiszer-Kierzkowska
authors.forename: Katarzyna
authors.initials: K
authors.lastname: Lisowska
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Slotte
authors.forename: Lea
authors.initials: L
authors.lastname: Sistonen
authors.forename: Ibolya
authors.initials: I
authors.lastname: Horváth
authors.forename: László
authors.initials: L
authors.lastname: Vígh
mesh_terms: D000818:Animals; D019905:Benzyl Alcohol / Q000494:pharmacology; D045744:Cell Line, Tumor; D004268:DNA-Binding Proteins / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D018840:HSP70 Heat-Shock Proteins / Q000235:genetics; D000076249:Heat Shock Transcription Factors; D018869:Heat-Shock Response; D006358:Hot Temperature; D008051:Lipid Bilayers / Q000378:metabolism; D008546:Melanoma, Experimental / Q000378:metabolism*; D008560:Membrane Fluidity; D021962:Membrane Microdomains / Q000502:physiology*; D051379:Mice; D010626:Phenylethyl Alcohol / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D014157:Transcription Factors / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; D018840:HSP70 Heat-Shock Proteins; D000076249:Heat Shock Transcription Factors; C490017:Hsf1 protein, mouse; D008051:Lipid Bilayers; D014157:Transcription Factors; D019905:Benzyl Alcohol; D010626:Phenylethyl Alcohol