title: Nutritional lipid supply can control the heat shock response of B16 melanoma cells in culture.
abstract: The in vitro culture of cells offers an extremely valuable method for probing biochemical questions and many commonly-used protocols are available. For mammalian cells a source of lipid is usually provided in the serum component. In this study we examined the question as to whether the nature of the lipid could become limiting at high cell densities and, therefore, prospectively influence the metabolism and physiology of the cells themselves. When B16 mouse melanoma cells were cultured, we noted a marked decrease in the proportions of n-3 and n-6 polyunsaturated fatty acids (PUFAs) with increasing cell density. This was despite considerable quantities of these PUFAs still remaining in the culture medium and seemed to reflect the preferential uptake of unesterified PUFA rather than other lipid classes from the media. The reduction in B16 total PUFA was reflected in changes in about 70% of the molecular species of membrane phosphoglycerides which were analysed by mass spectrometry. The importance of this finding lies in the need for n-3 and n-6 PUFA in mammalian cells (which cannot synthesize their own). Although the cholesterol content of cells was unchanged the amount of cholesterol enrichment in membrane rafts (as assessed by fluorescence) was severely decreased, simultaneous with a reduced heat shock response following exposure to 42°C. These data emphasize the pivotal role of nutrient supply (in this case for PUFAs) in modifying responses to stress and highlight the need for the careful control of culture conditions when assessing cellular responses in vitro.
authors.affiliation: Institute of Biochemistry, Biological Research Centre, Hungarian Academy of Sciences, Szeged, Hungary.
authors.forename: Mária
authors.initials: M
authors.lastname: Péter
authors.forename: Gábor
authors.initials: G
authors.lastname: Balogh
authors.forename: Imre
authors.initials: I
authors.lastname: Gombos
authors.forename: Gerhard
authors.initials: G
authors.lastname: Liebisch
authors.forename: Ibolya
authors.initials: I
authors.lastname: Horváth
authors.forename: Zsolt
authors.initials: Z
authors.lastname: Török
authors.forename: Enikő
authors.initials: E
authors.lastname: Nagy
authors.forename: Andriy
authors.initials: A
authors.lastname: Maslyanko
authors.forename: Sándor
authors.initials: S
authors.lastname: Benkő
authors.forename: Gerd
authors.initials: G
authors.lastname: Schmitz
authors.forename: John L
authors.initials: JL
authors.lastname: Harwood
authors.forename: László
authors.initials: L
authors.lastname: Vígh
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D003470:Culture Media / Q000494:pharmacology; D005231:Fatty Acids, Unsaturated / Q000378:metabolism / Q000494:pharmacology*; D020404:Glycerophospholipids / Q000378:metabolism*; D018869:Heat-Shock Response / Q000187:drug effects*; D006358:Hot Temperature; D008545:Melanoma / Q000378:metabolism* / Q000473:pathology; D051379:Mice
chemical_list: D003470:Culture Media; D005231:Fatty Acids, Unsaturated; D020404:Glycerophospholipids