title: Tumor suppressor p16INK4a--modulator of glycomic profile and galectin-1 expression to increase susceptibility to carbohydrate-dependent induction of anoikis in pancreatic carcinoma cells.
abstract: Expression of the tumor suppressor p16(INK4a) after stable transfection can restore the susceptibility of epithelial tumor cells to anoikis. This property is linked to increases in the expression and cell-surface presence of the fibronectin receptor. Considering its glycan chains as pivotal signals, we assumed an effect of p16(INK4a) on glycosylation. To test this hypothesis for human Capan-1 pancreatic carcinoma cells, we combined microarray for selected glycosyltransferase genes with 2D chromatographic glycan profiling and plant lectin binding. Major differences between p16-positive and control cells were detected. They concerned expression of beta1,4-galactosyltransferases (down-regulation of beta1,4-galactosyltransferases-I/V and up-regulation of beta1,4-galactosyltransferase-IV) as well as decreased alpha2,3-sialylation of O-glycans and alpha2,6-sialylation of N-glycans. The changes are compatible with increased beta(1)-integrin maturation, subunit assembly and binding activity of the alpha(5)beta(1)-integrin. Of further functional relevance in line with our hypothesis, we revealed differential reactivity towards endogenous lectins, especially galectin-1. As a result of reduced sialylation, the cells' capacity to bind galectin-1 was enhanced. In parallel, the level of transcription of the galectin-1 gene increased conspicuously in p16(INK4a)-positive cells, and even figured prominently in a microarray on 1996 tumor-associated genes and in proteomic analysis. The cells therefore gain optimal responsiveness. The correlation between genetically modulated galectin-1 levels and anoikis rates in engineered transfectants inferred functional significance. To connect these findings to the fibronectin receptor, galectin-1 was shown to be co-immunoprecipitated. We conclude that p16(INK4a) orchestrates distinct aspects of glycosylation that are relevant for integrin maturation and reactivity to an endogenous effector as well as the effector's expression. This mechanism establishes a new aspect of p16(INK4a) functionality.
authors.affiliation: Institute of Physiological Chemistry, Faculty of Veterinary Medicine, Ludwig-Maximilians-University Munich, Germany. Sabine.Andre@lmu.de
authors.forename: Sabine
authors.initials: S
authors.lastname: André
authors.forename: Hugo
authors.initials: H
authors.lastname: Sanchez-Ruderisch
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Nakagawa
authors.forename: Malte
authors.initials: M
authors.lastname: Buchholz
authors.forename: Jürgen
authors.initials: J
authors.lastname: Kopitz
authors.forename: Pia
authors.initials: P
authors.lastname: Forberich
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Kemmner
authors.forename: Corina
authors.initials: C
authors.lastname: Böck
authors.forename: Kisaburo
authors.initials: K
authors.lastname: Deguchi
authors.forename: Katharia M
authors.initials: KM
authors.lastname: Detjen
authors.forename: Bertram
authors.initials: B
authors.lastname: Wiedenmann
authors.forename: Magnus
authors.initials: M
authors.lastname: von Knebel Doeberitz
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Gress
authors.forename: Shin-Ichiro
authors.initials: S
authors.lastname: Nishimura
authors.forename: Stefan
authors.initials: S
authors.lastname: Rosewicz
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Gabius
mesh_terms: D023102:Anoikis; D002462:Cell Membrane / Q000378:metabolism; D002845:Chromatography; D019941:Cyclin-Dependent Kinase Inhibitor p16 / Q000502:physiology*; D037483:Galectin 1 / Q000096:biosynthesis*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D006031:Glycosylation; D006801:Humans; D037102:Lectins / Q000737:chemistry; D020411:Oligonucleotide Array Sequence Analysis; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000378:metabolism*; D040901:Proteomics; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D019941:Cyclin-Dependent Kinase Inhibitor p16; D037483:Galectin 1; D037102:Lectins; D012333:RNA, Messenger