title: Kynurenine Signaling Increases DNA Polymerase Kappa Expression and Promotes Genomic Instability in Glioblastoma Cells.
abstract: Overexpression of the translesion synthesis polymerase hpol κ in glioblastomas has been linked to poor patient prognosis; however, the mechanism promoting higher expression in these tumors remains unknown. We determined that activation of the aryl hydrocarbon receptor (AhR) pathway in glioblastoma cells leads to increased hpol κ mRNA and protein levels. We blocked nuclear translocation and DNA binding by AhR in glioblastoma cells using a small-molecule and observed decreased hpol κ expression. Pharmacological inhibition of tryptophan-2,3-dioxygenase (TDO), the enzyme largely responsible for activating AhR in glioblastoma, led to a decrease in the endogenous AhR agonist kynurenine and a corresponding decrease in hpol κ protein levels. Importantly, we discovered that inhibiting TDO activity, AhR signaling, or suppressing hpol κ expression with RNA interference led to decreased chromosomal damage in glioblastoma cells. Epistasis assays further supported the idea that TDO activity, activation of AhR signaling, and the resulting overexpression of hpol κ function primarily in the same pathway to increase endogenous DNA damage. These findings indicate that upregulation of hpol κ through glioblastoma-specific TDO activity and activation of AhR signaling likely contributes to the high levels of replication stress and genomic instability observed in these tumors.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: April C L
authors.initials: AC
authors.lastname: Bostian
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Leena
authors.initials: L
authors.lastname: Maddukuri
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Megan R
authors.initials: MR
authors.lastname: Reed
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Tatsiana
authors.initials: T
authors.lastname: Savenka
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Jessica H
authors.initials: JH
authors.lastname: Hartman
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Lauren
authors.initials: L
authors.lastname: Davis
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Dakota L
authors.initials: DL
authors.lastname: Pouncey
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Grover P
authors.initials: GP
authors.lastname: Miller
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences , Little Rock, Arkansas 72205-7199, United States.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Eoff
mesh_terms: D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology; D042822:Genomic Instability / Q000235:genetics*; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D007211:Indoles / Q000737:chemistry / Q000494:pharmacology; D007737:Kynurenine / Q000378:metabolism*; D015394:Molecular Structure; D011401:Promoter Regions, Genetic / Q000235:genetics*; D015398:Signal Transduction; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D000099270:Y-Family DNA Polymerases
chemical_list: D004259:DNA-Directed DNA Polymerase; D004791:Enzyme Inhibitors; D007211:Indoles; D007737:Kynurenine; C093792:TDO inhibitor LM10; C404302:POLK protein, human; D000099270:Y-Family DNA Polymerases