title: Inhibition of mixed-lineage kinase (MLK) activity during G2-phase disrupts microtubule formation and mitotic progression in HeLa cells.
abstract: The mixed-lineage kinases (MLK) are serine/threonine protein kinases that regulate mitogen-activated protein (MAP) kinase signaling pathways in response to extracellular signals. Recent studies indicate that MLK activity may promote neuronal cell death through activation of the c-Jun NH2-terminal kinase (JNK) family of MAP kinases. Thus, inhibitors of MLK activity may be clinically useful for delaying the progression of neurodegenerative diseases, such as Parkinson's. In proliferating non-neuronal cells, MLK may have the opposite effect of promoting cell proliferation. In the current studies we examined the requirement for MLK proteins in regulating cell proliferation by examining MLK function during G2 and M-phase of the cell cycle. The MLK inhibitor CEP-11004 prevented HeLa cell proliferation by delaying mitotic progression. Closer examination revealed that HeLa cells treated with CEP-11004 during G2-phase entered mitosis similar to untreated G2-phase cells. However, CEP-11004 treated cells failed to properly exit mitosis and arrested in a pro-metaphase state. Partial reversal of the CEP-11004 induced mitotic arrest could be achieved by overexpression of exogenous MLK3. The effects of CEP-11004 treatment on mitotic events included the inhibition of histone H3 phosphorylation during prophase and prior to nuclear envelope breakdown and the formation of aberrant mitotic spindles. These data indicate that MLK3 might be a unique target to selectively inhibit transformed cell proliferation by disrupting mitotic spindle formation resulting in mitotic arrest.
authors.affiliation: Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy Baltimore, Maryland, USA.
authors.forename: Hyukjin
authors.initials: H
authors.lastname: Cha
authors.forename: Surabhi
authors.initials: S
authors.lastname: Dangi
authors.forename: Carolyn E
authors.initials: CE
authors.lastname: Machamer
authors.forename: Paul
authors.initials: P
authors.lastname: Shapiro
mesh_terms: D000818:Animals; D002227:Carbazoles / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D016195:G2 Phase / Q000187:drug effects / Q000502:physiology*; D006367:HeLa Cells; D006657:Histones / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D020930:MAP Kinase Kinase Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051379:Mice; D008870:Microtubules / Q000187:drug effects / Q000378:metabolism*; D008938:Mitosis / Q000187:drug effects / Q000502:physiology*; D041681:NIH 3T3 Cells; D010766:Phosphorylation; D017346:Protein Serine-Threonine Kinases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D008941:Spindle Apparatus / Q000378:metabolism; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11
chemical_list: D002227:Carbazoles; D004791:Enzyme Inhibitors; D006657:Histones; D007211:Indoles; D020930:MAP Kinase Kinase Kinases; D017346:Protein Serine-Threonine Kinases; D000097767:Mitogen-Activated Protein Kinase Kinase Kinase 11; C469298:CEP-11004