title: Doublecortin induces mitotic microtubule catastrophe and inhibits glioma cell invasion.
abstract: Doublecortin (DCX) is a microtubule (MT) binding protein that induces growth arrest at the G2-M phase of cell cycle in glioma and suppresses tumor xenograft in immunocompromised hosts. DCX expression was found in neuronal cells, but lacking in glioma cells. We tested the hypothesis that DCX inhibits glioma U87 cell mitosis and invasion. Our data showed that DCX synthesizing U87 cells underwent mitotic MT spindle catastrophe in a neurabin II dependent pathway. Synthesis of both DCX and neurabin II were required to induce apoptosis in U87 and human embryonic kidney 293T cells. In DCX expressing U87 cells, association of phosphorylated DCX with protein phosphatase-1 (PP1) in the cytosol disrupted the interaction between kinesin-13 and PP1 in the nucleus and yielded spontaneously active kinesin-13. The activated kinesin-13 caused mitotic MT catastrophe in spindle checkpoint. Phosphorylated-DCX induced depolymerization of actin filaments in U87 cells, down-regulated matrix metalloproteinases-2 and -9, and inhibited glioma U87 cell invasion in a neurabin II dependent pathway. Thus, localization of the DCX-neurabin II-PP1 complex in the cytosol of U87 tumor cells inhibited PP1 phosphatase activities leading to anti-glioma effects via (1) mitotic MT spindle catastrophe that blocks mitosis and (2) depolymerization of actin that inhibits glioma cell invasion.
authors.affiliation: Department of Neurology, Henry Ford Health System, Detroit, Michigan, USA.
authors.forename: Manoranjan
authors.initials: M
authors.lastname: Santra
authors.forename: Sutapa
authors.initials: S
authors.lastname: Santra
authors.forename: Cindi
authors.initials: C
authors.lastname: Roberts
authors.forename: Rui Lan
authors.initials: RL
authors.lastname: Zhang
authors.forename: Michael
authors.initials: M
authors.lastname: Chopp
mesh_terms: D008841:Actin Cytoskeleton; D000328:Adult; D000704:Analysis of Variance; D000818:Animals; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D002465:Cell Movement; D049109:Cell Proliferation; D002478:Cells, Cultured; D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D005434:Flow Cytometry; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D020287:In Situ Nick-End Labeling / Q000379:methods; D016547:Kinesins / Q000378:metabolism; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D051379:Mice; D008819:Mice, Nude; D008840:Microfilament Proteins / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000235:genetics / Q000378:metabolism*; D008938:Mitosis / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009457:Neuroglia / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D054645:Protein Phosphatase 1 / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D051381:Rats; D008941:Spindle Apparatus / Q000502:physiology*; D014162:Transfection / Q000379:methods; D014407:Tumor Cells, Cultured; D055815:Young Adult; D000099273:Neurabins
chemical_list: D000089622:Doublecortin Domain Proteins; D000089662:Doublecortin Protein; D016547:Kinesins; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9; D008840:Microfilament Proteins; D008869:Microtubule-Associated Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D054645:Protein Phosphatase 1; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D000099273:Neurabins; C000714328:DCX protein, human; C000714847:Dcx protein, mouse; C000714848:Dcx protein, rat