title: Knockdown of NPM1 by RNA interference inhibits cells proliferation and induces apoptosis in leukemic cell line.
abstract: Nucleophosmin (NPM1) is an abundant and ubiquitously expressed phosphoprotein that is known to influence solid tumors progression. However, little is known about the role of NPM1 in leukemia. Here, we knocked down the NPM1 expression by RNA interference to investigate the role of NPM1 in leukemic cells proliferation and apoptosis. The interference vector pNPM1-shRNA was constructed and transfected into the human leukemic K562 cell line. The expression levels of NPM1 mRNA and protein were detected by quantitative real-time PCR and Western blot, respectively. Cells proliferation potential in vitro was assessed by methyl thiazolyl tetrazolium (MTT) and colony formation assays. Flow cytometry was used to detect the distribution of cell cycle. Cellular apoptosis was reflected by the relative activities of caspase-3 and caspase-8. The results showed that the expression levels of NPM1 mRNA and protein in K562 cells were significantly reduced after pNPM1-shRNA transfection. The cells growth was significantly inhibited in a time-dependent manner and the number of colonies was significantly reduced in the pNPM1-shRNA transfected cells. Meanwhile, the percentage of cells in G1 phase in the K562/pNPM1-shRNA cells was significantly increased. In addition, there were higher relative activities of caspase-3/8 in the pNPM1-shRNA transfected cells. These results indicate that down-regulation of NPM1 expression inhibits leukemic cells proliferation, blocks cell cycle progression and induces cellular apoptosis. It may implicate a potential target for leukemia gene therapy.
authors.affiliation: Key Laboratory of Laboratory Medical Diagnostics, Ministry of Education, Department of Laboratory Medicine, Chongqing Medical University, Chongqing 400016, China.
authors.forename: Feng-Xian
authors.initials: FX
authors.lastname: Qin
authors.forename: Hui-Yuan
authors.initials: HY
authors.lastname: Shao
authors.forename: Xian-Chun
authors.initials: XC
authors.lastname: Chen
authors.forename: Shi
authors.initials: S
authors.lastname: Tan
authors.forename: Hui-Juan
authors.initials: HJ
authors.lastname: Zhang
authors.forename: Zong-Yu
authors.initials: ZY
authors.lastname: Miao
authors.forename: Li
authors.initials: L
authors.lastname: Wang
authors.lastname: Hui-Chen
authors.forename: Ling
authors.initials: L
authors.lastname: Zhang
mesh_terms: D017209:Apoptosis / Q000235:genetics / Q000502:physiology*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005434:Flow Cytometry; D006801:Humans; D007938:Leukemia / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism*; D000090243:Nucleophosmin; D034622:RNA Interference / Q000502:physiology
chemical_list: C000716967:NPM1 protein, human; D009687:Nuclear Proteins; D000090243:Nucleophosmin