title: Shiga toxin glycosphingolipid receptor expression and toxin susceptibility of human pancreatic ductal adenocarcinomas of differing origin and differentiation.
abstract: Shiga toxins (Stxs) are composed of an enzymatically active A subunit (StxA) and a pentameric B subunit (StxB) that preferentially binds to the glycosphingolipid (GSL) globo\xadtriaosylceramide (Gb3Cer/CD77) and to a reduced extent to globotetraosylceramide (Gb4Cer). The identification of Gb3Cer as a tumor-associated GSL in human pancreatic cancer prompted us to investigate the expression of Gb3Cer and Gb4Cer in 15 human pancreatic ductal adenocarcinoma cell lines derived from primary tumors and liver, ascites, and lymph node metastases. Thin-layer chromatography overlay assays revealed the occurrence of Gb3Cer in all and of Gb4Cer in the majority of cell lines, which largely correlated with transcriptional expression analysis of Gb3Cer and Gb4Cer synthases. Prominent Gb3Cer and Gb4Cer lipoform heterogeneity was based on ceramides carrying predominantly C16:0 and C24:0/C24:1 fatty acids. Stx2-mediated cell injury ranged from extremely high sensitivity (CD(50) of 0.94 pg/ml) to high refractiveness (CD(50) of 5.8 μg/ml) and to virtual resistance portrayed by non-determinable CD(50) values even at the highest Stx2 concentration (10 μg/ml) applied. Importantly, Stx2-mediated cytotoxicity did not correlate with Gb3Cer expression (the preferential Stx receptor), suggesting that the GSL receptor content does not primarily determine cell sensitivity and that other, yet to be delineated, cellular factors might influence the responsiveness of cancer cells.
authors.affiliation: Institute for Hygiene, University of Münster, D-48149 Münster, Germany.
authors.forename: Wiebke
authors.initials: W
authors.lastname: Storck
authors.forename: Iris
authors.initials: I
authors.lastname: Meisen
authors.forename: Kathrin
authors.initials: K
authors.lastname: Gianmoena
authors.forename: Ina
authors.initials: I
authors.lastname: Pläger
authors.forename: Ivan U
authors.initials: IU
authors.lastname: Kouzel
authors.forename: Martina
authors.initials: M
authors.lastname: Bielaszewska
authors.forename: Jörg
authors.initials: J
authors.lastname: Haier
authors.forename: Michael
authors.initials: M
authors.lastname: Mormann
authors.forename: Hans-Ulrich
authors.initials: HU
authors.lastname: Humpf
authors.forename: Helge
authors.initials: H
authors.lastname: Karch
authors.forename: Johannes
authors.initials: J
authors.lastname: Müthing
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology / Q000556:secondary; D001201:Ascites / Q000473:pathology; D021441:Carcinoma, Pancreatic Ductal / Q000188:drug therapy / Q000235:genetics* / Q000473:pathology / Q000556:secondary; D045744:Cell Line, Tumor; D002470:Cell Survival / Q000187:drug effects*; D015972:Gene Expression Regulation, Neoplastic; D005915:Globosides / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D008113:Liver Neoplasms / Q000473:pathology; D008198:Lymph Nodes / Q000473:pathology; D022641:Shiga Toxin 2 / Q000302:isolation & purification / Q000494:pharmacology*; D054323:Shiga-Toxigenic Escherichia coli / Q000737:chemistry; D014281:Trihexosylceramides / Q000032:analysis / Q000235:genetics* / Q000378:metabolism
chemical_list: D005915:Globosides; D022641:Shiga Toxin 2; D014281:Trihexosylceramides; C024032:globotetraosylceramide; C018549:globotriaosylceramide