title: Implications of targeted genomic disruption of β-catenin in BxPC-3 pancreatic adenocarcinoma cells.
abstract: Pancreatic adenocarcinoma (PA) is among the most aggressive human tumors with an overall 5-year survival rate of <5% and available treatments are only minimal effective. WNT/β-catenin signaling has been identified as one of 12 core signaling pathways that are commonly mutated in PA. To obtain more insight into the role of WNT/β-catenin signaling in PA we established human PA cell lines that are deficient of the central canonical WNT signaling protein β-catenin by using zinc-finger nuclease (ZFN) mediated targeted genomic disruption in the β-catenin gene (CTNNB1). Five individual CTNNB1 gene disrupted clones (BxPC3ΔCTNNB1) were established from a BxPC-3 founder cell line. Despite the complete absence of β-catenin, all clones displayed normal cell cycle distribution profiles, overall normal morphology and no elevated levels of apoptosis although increased doubling times were observed in three of the five BxPC3ΔCTNNB1 clones. This confirms that WNT/β-catenin signaling is not mandatory for long term cell growth and survival in BxPC-3 cells. Despite a normal morphology of the β-catenin deficient cell lines, quantitative proteomic analysis combined with pathway analysis showed a significant down regulation of proteins implied in cell adhesion combined with an up-regulation of plakoglobin. Treatment of BxPC3ΔCTNNB1 cell lines with siRNA for plakoglobin induced morphological changes compatible with a deficiency in the formation of functional cell to cell contacts. In addition, a re-localization of E-cadherin from membranous in untreated to accumulation in cytoplasmatic puncta in plakoglobin siRNA treated BxPC3ΔCTNNB1 cells was observed. In conclusion we describe in β-catenin deficient BxPC-3 cells a rescue function for plakoglobin on cell to cell contacts and maintaining the localization of E-cadherin at the cellular surface, but not on canonical WNT signaling as measured by TFC/LEF mediated transcription.
authors.affiliation: Unit for Cell Signaling, Cancer Stem Cell Innovation Centre (SFI-CAST), Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Petter Angell
authors.initials: PA
authors.lastname: Olsen
authors.affiliation: Unit for Cell Signaling, Cancer Stem Cell Innovation Centre (SFI-CAST), Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Nina Therese
authors.initials: NT
authors.lastname: Solberg
authors.affiliation: Unit for Cell Signaling, Cancer Stem Cell Innovation Centre (SFI-CAST), Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Kaja
authors.initials: K
authors.lastname: Lund
authors.affiliation: Department of Chemistry, University of Oslo, Oslo, Norway.
authors.forename: Tore
authors.initials: T
authors.lastname: Vehus
authors.affiliation: Unit for Cell Signaling, Cancer Stem Cell Innovation Centre (SFI-CAST), Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Monika
authors.initials: M
authors.lastname: Gelazauskaite
authors.affiliation: Department of Chemistry, University of Oslo, Oslo, Norway.
authors.forename: Steven Ray
authors.initials: SR
authors.lastname: Wilson
authors.affiliation: Unit for Cell Signaling, Cancer Stem Cell Innovation Centre (SFI-CAST), Oslo University Hospital-Rikshospitalet, Oslo, Norway.
authors.forename: Stefan
authors.initials: S
authors.lastname: Krauss
mesh_terms: D000230:Adenocarcinoma / Q000235:genetics* / Q000473:pathology; D022005:Adherens Junctions / Q000378:metabolism; D017209:Apoptosis / Q000235:genetics; D001483:Base Sequence; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004705:Endocytosis; D004722:Endoribonucleases / Q000378:metabolism; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D063990:Gene Ontology; D018390:Gene Targeting; D015894:Genome, Human; D006801:Humans; D007553:Isotope Labeling; D008969:Molecular Sequence Data; D050505:Mutant Proteins / Q000378:metabolism; D010190:Pancreatic Neoplasms / Q000235:genetics* / Q000473:pathology; D021381:Protein Transport; D051820:TCF Transcription Factors / Q000378:metabolism; D015533:Transcriptional Activation / Q000235:genetics; D051178:alpha Catenin / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism*; D051185:gamma Catenin / Q000378:metabolism
chemical_list: D015820:Cadherins; D050505:Mutant Proteins; D051820:TCF Transcription Factors; D051178:alpha Catenin; D051176:beta Catenin; D051185:gamma Catenin; D004722:Endoribonucleases