title: Up-regulation of lactosylceramide synthase in MDR1 overexpressing human liver tumour cells.
abstract: HepG2 cells, stably transfected with MDR1 cDNA, encoding the P-glycoprotein multidrug resistance efflux pump, display an altered sphingolipid composition compared to control cells, stably transfected with empty vector. The MDR1 overexpressing cells display a approximately 3-fold increased level of lactosylceramide and an increased ganglioside mass. Both the mRNA and the activity of lactosylceramide synthase were increased in HepG2/MDR1 cells. In conclusion, the increased glycolipid content in MDR1-transfected HepG2 cells is caused by a transcriptional up-regulation of the enzyme lactosylceramide synthase.
authors.affiliation: University Medical Center Groningen, Department of Cell Biology, Section Membrane Cell Biology, A. Deusinglaan 1, Bldg 3215, 10th fl, 9713 AV Groningen, The Netherlands. c.a.hummel@med.umcg.nl
authors.forename: Ina
authors.initials: I
authors.lastname: Hummel
authors.forename: Karin
authors.initials: K
authors.lastname: Klappe
authors.forename: Jan Willem
authors.initials: JW
authors.lastname: Kok
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D005700:Galactosyltransferases / Q000096:biosynthesis* / Q000235:genetics; D005732:Gangliosides / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000201:enzymology* / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D014158:Transcription, Genetic; D015533:Transcriptional Activation; D014162:Transfection; D015854:Up-Regulation
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D005732:Gangliosides; D012333:RNA, Messenger; D005700:Galactosyltransferases; C039090:UDPgalactose-glucosylceramide galactosyltransferase