title: Amsacrine-induced apoptosis of human leukemia U937 cells is mediated by the inhibition of AKT- and ERK-induced stabilization of MCL1.
abstract: Previous studies have attributed the anticancer activity of amsacrine to its inhibitory effect on topoisomerase II. However, 9-aminoacridine derivatives, which have the same structural scaffold as amsacrine, induce cancer cell apoptosis by altering the expression of BCL2 family proteins. Therefore, in the present study, we assessed whether BCL2 family proteins mediated the cytotoxic effects of amsacrine on human leukemia U937 cells. Amsacrine-induced apoptosis of U937 cells was characterized by caspase-9 and caspase-3 activation, increased intracellular Ca2+concentration, mitochondrial depolarization, and MCL1 down-regulation. Amsacrine induced MCL1 down-regulation by decreasing its stability. Further, amsacrine-treated U937 cells showed AKT degradation and Ca2+-mediated ERK inactivation. Blockade of ERK-mediated phosphorylation of MCL1 inhibited the effect of Pin1 on the stabilization of MCL1, and AKT degradation promoted GSK3β-mediated degradation of MCL1. Restoration of ERK phosphorylation and AKT expression abrogated amsacrine-induced MCL1 down-regulation. Moreover, MCL1 over-expression inhibited amsacrine-induced depolarization of mitochondria membrane and increased the viability of amsacrine-treated cells. Taken together, our data indicate that amsacrine abolishes ERK- and Pin1-mediated stabilization of MCL1 and promotes GSK3β-mediated degradation of MCL1, leading to activate mitochondria-mediated apoptosis pathway in U937 cells.
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan.
authors.forename: Yuan-Chin
authors.initials: YC
authors.lastname: Lee
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan.
authors.forename: Ying-Jung
authors.initials: YJ
authors.lastname: Chen
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan.
authors.forename: Chia-Hui
authors.initials: CH
authors.lastname: Huang
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University, Kaohsiung, 804, Taiwan. lschang@mail.nsysu.edu.tw.|Department of Biotechnology, Kaohsiung Medical University, Kaohsiung, 807, Taiwan. lschang@mail.nsysu.edu.tw.
authors.forename: Long-Sen
authors.initials: LS
authors.lastname: Chang
mesh_terms: D000677:Amsacrine / Q000494:pharmacology*; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D005047:Etoposide / Q000494:pharmacology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000037:antagonists & inhibitors* / Q000502:physiology; D000071679:Glycogen Synthase Kinase 3 beta / Q000378:metabolism; D006801:Humans; D048369:MAP Kinase Kinase 1 / Q000235:genetics / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects; D064549:Myeloid Cell Leukemia Sequence 1 Protein / Q000378:metabolism*; D000072340:NIMA-Interacting Peptidylprolyl Isomerase / Q000037:antagonists & inhibitors; D010766:Phosphorylation / Q000187:drug effects; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D011499:Protein Processing, Post-Translational / Q000187:drug effects; D055550:Protein Stability / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors* / Q000502:physiology; D017382:Reactive Oxygen Species / Q000378:metabolism; D011994:Recombinant Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D020298:U937 Cells
chemical_list: D000970:Antineoplastic Agents; C579095:MCL1 protein, human; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D000072340:NIMA-Interacting Peptidylprolyl Isomerase; D017382:Reactive Oxygen Species; D011994:Recombinant Proteins; D000677:Amsacrine; D005047:Etoposide; C494918:AKT1 protein, human; C000605506:GSK3B protein, human; D000071679:Glycogen Synthase Kinase 3 beta; D051057:Proto-Oncogene Proteins c-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D046988:Proteasome Endopeptidase Complex; C000606846:PIN1 protein, human; D002118:Calcium
keywords: AKT; Amsacrine; ERK; GSK3β; Leukemia cells; MCL1 stability