title: Membrane type sialidase inhibits the megakaryocytic differentiation of human leukemia K562 cells.
abstract: The membrane type sialidase (Neu3) has been suggested to participate in cell growth, migration and differentiation. To determine whether a Neu3 is able to modulate megakaryocytic differentiation of K562 cells, we studied the functional significance of human Neu3 induced by phorbol 12-myristate 13-acetate (PMA). Northern blot and reverse transcription-polymerase chain reaction (RT-PCR) indicated that the induction of hST3Gal V, which synthesizes ganglioside GM3 and reduction of Neu3 by PMA, are linked for the expression of differentiation marker protein, CD41b surface antigen. To elucidate the mechanism underlying the down-regulation of the CD41b surface antigen expression when Neu3 gene is expressed in PMA-treated cells, we characterized the Neu3-mediated signaling pathway. Neu3 overexpression inhibited the PMA-induced ERK1/2 and p38 MAPK phosphorylation in the K562 cells. Down-regulation of expression of CD41b surface antigen was dependent on expression of Neu3 gene. However, a Neu3 inhibitor Neu5Ac2en induced morphological changes, showing megakaryocytic differentiation of K562 cells, with expression of CD41b surface antigen, while a specific glucosylceramide synthase inhibitor PDMP inhibited megakaryocytic differentiation of K562 cells. The molecular mechanisms involved in Neu3-involved inhibition of CD41b surface antigen expression in K562 cells have been suggested: the Neu3 degrades membrane sialic acids and the resulting signaling pathway of the PKC/ERKs/p38 MAPK is down-regulated, causing a decrease in CD41b surface antigen expression and inhibition of megakaryocytic differentiation of K562 cells.
authors.affiliation: Molecular and Cellular Glycobiology Unit, Department of Biological Science, Sungkyunkwan University, Chunchun-Dong 300, Suwon, Kyunggi-Do 440-746, South Korea.
authors.forename: Un-Ho
authors.initials: UH
authors.lastname: Jin
authors.forename: Ki-Tae
authors.initials: KT
authors.lastname: Ha
authors.forename: Kyung-Woon
authors.initials: KW
authors.lastname: Kim
authors.forename: Young-Chae
authors.initials: YC
authors.lastname: Chang
authors.forename: Young-Coon
authors.initials: YC
authors.lastname: Lee
authors.forename: Jeong-Heon
authors.initials: JH
authors.lastname: Ko
authors.forename: Cheorl-Ho
authors.initials: CH
authors.lastname: Kim
mesh_terms: D015152:Blotting, Northern; D015153:Blotting, Western; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology*; D002462:Cell Membrane / Q000378:metabolism; D048430:Cell Shape / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D005679:G(M3) Ganglioside / Q000378:metabolism; D015973:Gene Expression Regulation, Leukemic / Q000187:drug effects; D005964:Glucosyltransferases / Q000037:antagonists & inhibitors; D006801:Humans; D039421:Integrin alpha2 / Q000235:genetics; D020014:K562 Cells; D008533:Megakaryocytes / Q000166:cytology*; D008954:Models, Biological; D009025:Morpholines / Q000494:pharmacology; D019158:N-Acetylneuraminic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D009439:Neuraminidase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D011493:Protein Kinase C / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012799:Sialyltransferases / Q000235:genetics; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D005679:G(M3) Ganglioside; C056564:ITGA2B protein, human; D039421:Integrin alpha2; D009025:Morpholines; C036137:2-deoxy-2,3-dehydro-N-acetylneuraminic acid; C033110:RV 538; D005964:Glucosyltransferases; C023246:ceramide glucosyltransferase; D012799:Sialyltransferases; C021343:haematoside synthetase; D011493:Protein Kinase C; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C465436:Neu3 protein, human; D009439:Neuraminidase; D019158:N-Acetylneuraminic Acid; D013755:Tetradecanoylphorbol Acetate