title: Identification of early gene expression changes in primary cultured neurons treated with topoisomerase I poisons.
abstract: Topoisomerase 1 (TOP1) poisons like camptothecin (CPT) are currently used in cancer chemotherapy but these compounds can have damaging, off-target effects on neurons leading to cognitive, sensory and motor deficits. To understand the molecular basis for the enhanced sensitivity of neurons to CPT, we examined the effects of compounds that inhibit TOP1-CPT, actinomycin D (ActD) and β-lapachone (β-Lap)-on primary cultured rat motor (MN) and cortical (CN) neurons as well as fibroblasts. Neuronal cells expressed higher levels of Top1 mRNA than fibroblasts but transcript levels are reduced in all cell types after treatment with CPT. Microarray analysis was performed to identify differentially regulated transcripts in MNs in response to a brief exposure to CPT. Pathway analysis of the differentially expressed transcripts revealed activation of ERK and JNK signaling cascades in CPT-treated MNs. Immediate-early genes like Fos, Egr-1 and Gadd45b were upregulated in CPT-treated MNs. Fos mRNA levels were elevated in all cell types treated with CPT; Egr-1, Gadd45b and Dyrk3 transcript levels, however, increased in CPT-treated MNs and CNs but decreased in CPT-treated fibroblasts. These transcripts may represent new targets for the development of therapeutic agents that mitigate the off-target effects of chemotherapy on the nervous system.
authors.affiliation: Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Sharyn L
authors.initials: SL
authors.lastname: Rossi
authors.affiliation: Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA.
authors.forename: Casey J
authors.initials: CJ
authors.lastname: Lumpkin
authors.affiliation: Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Ashlee W
authors.initials: AW
authors.lastname: Harris
authors.affiliation: Biomolecular Core Laboratory, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Holbrook
authors.affiliation: Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA.
authors.forename: Cinsley
authors.initials: C
authors.lastname: Gentillon
authors.affiliation: Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Bioinformatics Core Facility, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, USA.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: McCahan
authors.affiliation: Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA.
authors.forename: Wenlan
authors.initials: W
authors.lastname: Wang
authors.affiliation: Center for Applied Clinical Genomics, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Center for Pediatric Research, Nemours Biomedical Research, Nemours Alfred I. duPont Hospital for Children, Wilmington, DE, USA; Department of Biological Sciences, University of Delaware, Newark, DE, USA; Department of Pediatrics, Thomas Jefferson University, Philadelphia, PA, USA. Electronic address: butchbach@nemoursresearch.org.
authors.forename: Matthew E R
authors.initials: MER
authors.lastname: Butchbach
mesh_terms: D000818:Animals; D000943:Antigens, Differentiation / Q000378:metabolism; D000970:Antineoplastic Agents / Q000737:chemistry; D002166:Camptothecin / Q000737:chemistry; D002478:Cells, Cultured; D004264:DNA Topoisomerases, Type I / Q000378:metabolism; D051767:Early Growth Response Protein 2 / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism; D005786:Gene Expression Regulation; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D059004:Topoisomerase I Inhibitors / Q000737:chemistry*; D000097642:GADD45 Proteins
chemical_list: D000943:Antigens, Differentiation; D000970:Antineoplastic Agents; D002166:Camptothecin; D004264:DNA Topoisomerases, Type I; D051767:Early Growth Response Protein 2; D017346:Protein Serine-Threonine Kinases; D011505:Protein-Tyrosine Kinases; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D059004:Topoisomerase I Inhibitors; C497328:Egr2 protein, rat; C508094:Gadd45b protein, rat; D000097642:GADD45 Proteins; C000619954:DYRK3 protein, rat
keywords: Actinomycin D; Camptothecin; Cortical neuron; DNA damage response; Dyrk3; Immediate early gene; Microarray; Motor neuron; β-lapachone