title: Keratin23 (KRT23) knockdown decreases proliferation and affects the DNA damage response of colon cancer cells.
abstract: Keratin 23 (KRT23) is strongly expressed in colon adenocarcinomas but absent in normal colon mucosa. Array based methylation profiling of 40 colon samples showed that the promoter of KRT23 was methylated in normal colon mucosa, while hypomethylated in most adenocarcinomas. Promoter methylation correlated with absent expression, while increased KRT23 expression in tumor samples correlated with promoter hypomethylation, as confirmed by bisulfite sequencing. Demethylation induced KRT23 expression in vitro. Expression profiling of shRNA mediated stable KRT23 knockdown in colon cancer cell lines showed that KRT23 depletion affected molecules of the cell cycle and DNA replication, recombination and repair. In vitro analyses confirmed that KRT23 depletion significantly decreased the cellular proliferation of SW948 and LS1034 cells and markedly decreased the expression of genes involved in DNA damage response, mainly molecules of the double strand break repair homologous recombination pathway. KRT23 knockdown decreased the transcript and protein expression of key molecules as e.g. MRE11A, E2F1, RAD51 and BRCA1. Knockdown of KRT23 rendered colon cancer cells more sensitive to irradiation and reduced proliferation of the KRT23 depleted cells compared to irradiated control cells.
authors.affiliation: Department of Molecular Medicine MOMA, Aarhus University Hospital, Skejby, Aarhus N, Denmark.
authors.forename: Karin
authors.initials: K
authors.lastname: Birkenkamp-Demtröder
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Hahn
authors.forename: Francisco
authors.initials: F
authors.lastname: Mansilla
authors.forename: Kasper
authors.initials: K
authors.lastname: Thorsen
authors.forename: Abdelouahid
authors.initials: A
authors.lastname: Maghnouj
authors.forename: Rikke
authors.initials: R
authors.lastname: Christensen
authors.forename: Bodil
authors.initials: B
authors.lastname: Øster
authors.forename: Torben Falck
authors.initials: TF
authors.lastname: Ørntoft
mesh_terms: D001483:Base Sequence; D015153:Blotting, Western; D002453:Cell Cycle / Q000235:genetics; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002470:Cell Survival / Q000235:genetics / Q000528:radiation effects; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004249:DNA Damage; D019175:DNA Methylation; D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005720:Gamma Rays; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D045325:HCT116 Cells; D057809:HEK293 Cells; D006801:Humans; D053530:Keratins, Type I / Q000235:genetics* / Q000378:metabolism; D000076228:MRE11 Homologue Protein; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D020411:Oligonucleotide Array Sequence Analysis; D034622:RNA Interference; D051135:Rad51 Recombinase / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D059467:Transcriptome / Q000235:genetics
chemical_list: D004268:DNA-Binding Proteins; C420247:KRT23 protein, human; D053530:Keratins, Type I; C121766:MRE11 protein, human; D051135:Rad51 Recombinase; D000076228:MRE11 Homologue Protein
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