title: Potentiation of paclitaxel-induced apoptosis by galectin-13 overexpression via activation of Ask-1-p38-MAP kinase and JNK/SAPK pathways and suppression of Akt and ERK1/2 activation in U-937 human macrophage cells.
abstract: Galectin-13 transcripts have been identified in several normal and malignant tissues, but the physiological function of galectin-13 is still poorly understood. Here, we present evidence for its possible role in promoting cell death in the U-937 human macrophage cell line. Transfection of U-937 human macrophages by a galectin-13 cDNA-containing mammalian expression vector increased the galectin-13 level and sensitized the cells to stress stimuli. Galectin-13 overexpression facilitated paclitaxel-induced cell death and nuclear translocation of apoptosis-inducing factor (AIF) and endonuclease-G without inducing mitochondrial cytochrome-c release or caspase-3 activation. Immunoblot and immunofluorescence data showed that overexpression of galectin-13 induced long-term activation of c-Jun N-terminal kinase (JNK) and p38-mitogen-activated protein kinase (MAPK) pathways, as well as activation of apoptosis signal-regulating kinase-1 (Ask-1) kinase while it suppressed paclitaxel-induced long-term activation of the phosphatidilylositol-3-kinase (PI-3K)-Akt and extracellular signal-regulated kinase (ERK1/2) cytoprotective pathways. In addition, pharmacological inhibition of JNK and p38-MAPK pathways protected the cells from paclitaxel-induced cell death. All this data indicate that galectin-13 overexpression promoted apoptosis presumably by activating the Ask-1 kinase-JNK and p38-MAPK pro-apoptotic pathways and by suppressing the PI-3K-Akt and ERK1/2 cytoprotective pathways.
authors.affiliation: Departments of Biochemistry and Medical Chemistry, University of Pécs, Pécs, Hungary.
authors.forename: Arpad
authors.initials: A
authors.lastname: Boronkai
authors.forename: Szabolcs
authors.initials: S
authors.lastname: Bellyei
authors.forename: Andras
authors.initials: A
authors.lastname: Szigeti
authors.forename: Eva
authors.initials: E
authors.lastname: Pozsgai
authors.forename: Zita
authors.initials: Z
authors.lastname: Bognar
authors.forename: Balazs
authors.initials: B
authors.lastname: Sumegi
authors.forename: Ferenc
authors.initials: F
authors.lastname: Gallyas
mesh_terms: D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D004789:Enzyme Activation; D037161:Galectins / Q000096:biosynthesis*; D006801:Humans; D015151:Immunoblotting; D048670:MAP Kinase Kinase 4 / Q000378:metabolism; D048848:MAP Kinase Kinase Kinase 5 / Q000378:metabolism; D020935:MAP Kinase Signaling System; D008264:Macrophages / Q000187:drug effects / Q000201:enzymology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D017239:Paclitaxel / Q000494:pharmacology*; D011257:Pregnancy Proteins / Q000096:biosynthesis*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D014162:Transfection; D020298:U937 Cells; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
chemical_list: D037161:Galectins; C038195:LGALS13 protein, human; D011257:Pregnancy Proteins; D051057:Proto-Oncogene Proteins c-akt; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D048848:MAP Kinase Kinase Kinase 5; D048670:MAP Kinase Kinase 4; D017239:Paclitaxel