title: Global functional analysis of nucleophosmin in Taxol response, cancer, chromatin regulation, and ribosomal DNA transcription.
abstract: Analysis of lung cancer response to chemotherapeutic agents showed the accumulation of a Taxol-induced protein that reacted with an anti-phospho-MEK1/2 antibody. Mass spectroscopy identified the protein as nucleophosmin/B23 (NPM), a multifunctional protein with diverse roles: ribosome biosynthesis, p53 regulation, nuclear-cytoplasmic shuttling, and centrosome duplication. Our work demonstrates that following cellular exposure to mitosis-arresting agents, NPM is phosphorylated and its chromatographic property is altered, suggesting changes in function during mitosis. To determine the functional relevance of NPM, its expression in tumor cells was reduced by siRNA. Cells with reduced NPM were treated with Taxol followed by microarray profiling accompanied by gene/protein pathway analyses. These studies demonstrate several expected and unexpected consequences of NPM depletion. The predominant downstream effectors of NPM are genes involved in cell proliferation, cancer, and the cell cycle. In congruence with its role in cancer, NPM is over-expressed in primary malignant lung cancer tissues. We also demonstrate a role for NPM in the expression of genes encoding SET (TAF1beta) and the histone methylase SET8. Additionally, we show that NPM is required for a previously unobserved G2/M upregulation of TAF1A, which encodes the rDNA transcription factor TAF(I)48. These results demonstrate multi-faceted functions of NPM that can affect cancer cells.
authors.affiliation: Curriculum in Genetics and Molecular Biology, Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA. dan.bergstralh@med.unc.edu
authors.forename: Daniel T
authors.initials: DT
authors.lastname: Bergstralh
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Conti
authors.forename: Chris B
authors.initials: CB
authors.lastname: Moore
authors.forename: W June
authors.initials: WJ
authors.lastname: Brickey
authors.forename: Debra J
authors.initials: DJ
authors.lastname: Taxman
authors.forename: Jenny P-Y
authors.initials: JP
authors.lastname: Ting
mesh_terms: D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D001483:Base Sequence; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002843:Chromatin / Q000187:drug effects / Q000235:genetics; D004273:DNA, Neoplasm / Q000235:genetics; D004275:DNA, Ribosomal / Q000235:genetics; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D048369:MAP Kinase Kinase 1 / Q000378:metabolism; D048370:MAP Kinase Kinase 2 / Q000378:metabolism; D008938:Mitosis / Q000187:drug effects / Q000235:genetics; D046912:Multiprotein Complexes; D009687:Nuclear Proteins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000090243:Nucleophosmin; D017239:Paclitaxel / Q000494:pharmacology*; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000235:genetics; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: D000972:Antineoplastic Agents, Phytogenic; D002843:Chromatin; D004273:DNA, Neoplasm; D004275:DNA, Ribosomal; D046912:Multiprotein Complexes; C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D034741:RNA, Small Interfering; D000090243:Nucleophosmin; C482128:MAP2K2 protein, human; D048369:MAP Kinase Kinase 1; D048370:MAP Kinase Kinase 2; C482125:MAP2K1 protein, human; D017239:Paclitaxel