title: Nek3 kinase regulates prolactin-mediated cytoskeletal reorganization and motility of breast cancer cells.
abstract: Prolactin (PRL) stimulates the cytoskeletal re-organization and motility of breast cancer cells. During PRL receptor signaling, Vav2 becomes phosphorylated and activated, an event regulated by the serine/threonine kinase Nek3. Given the regulatory role of Vav2, the function of Nek3 in PRL-mediated motility and invasion was examined. Overexpression of Nek3 in Chinese hamster ovary transfectants potentiated cytoskeletal re-organization in response to PRL. In contrast, downregulation of Nek3 expression by small-interfering RNA (siRNA) attenuated PRL-mediated cytoskeletal reorganization, activation of GTPase Rac1, cell migration and invasion of T47D cells. In addition, PRL stimulation induced an interaction between Nek3 and paxillin and significantly increased paxillin serine phosphorylation, whereas Nek3 siRNA-transfected cells showed a marked reduction in paxillin phosphorylation. Analysis of breast tissue microarrays also demonstrated a significant up-regulation of Nek3 expression in malignant versus normal specimens. These data suggest that Nek3 contributes to PRL-mediated breast cancer motility through mechanisms involving Rac1 activation and paxillin phosphorylation.
authors.affiliation: Department of Molecular Pharmacology and Chemistry, Memorial Sloan Kettering Cancer Center, New York, NY, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Miller
authors.forename: G
authors.initials: G
authors.lastname: Antico
authors.forename: P N
authors.initials: PN
authors.lastname: Raghunath
authors.forename: J E
authors.initials: JE
authors.lastname: Tomaszewski
authors.forename: C V
authors.initials: CV
authors.lastname: Clevenger
mesh_terms: D000818:Animals; D001943:Breast Neoplasms / Q000201:enzymology / Q000473:pathology*; D016466:CHO Cells; D045744:Cell Line, Tumor; D002465:Cell Movement; D006224:Cricetinae; D003412:Cricetulus; D003599:Cytoskeleton / Q000187:drug effects / Q000648:ultrastructure*; D005260:Female; D006801:Humans; D000072379:NIMA-Related Kinases; D009361:Neoplasm Invasiveness; D051419:Paxillin / Q000378:metabolism; D010766:Phosphorylation; D011388:Prolactin / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D051567:Proto-Oncogene Proteins c-vav / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D012694:Serine / Q000378:metabolism; D014162:Transfection; D020830:rac1 GTP-Binding Protein / Q000378:metabolism
chemical_list: D051419:Paxillin; D051567:Proto-Oncogene Proteins c-vav; D034741:RNA, Small Interfering; C093651:VAV2 protein, human; D012694:Serine; D011388:Prolactin; C486224:NEK3 protein, human; D000072379:NIMA-Related Kinases; D017346:Protein Serine-Threonine Kinases; D020830:rac1 GTP-Binding Protein