title: Aminopeptidase-N/CD13 is a potential proapoptotic target in human myeloid tumor cells.
abstract: The transmembrane metalloprotease aminopeptidase-N (APN)/CD13 is overexpressed in various solid and hematological malignancies in humans, including acute myeloid leukemia (AML) and is thought to influence tumor progression. Here, we investigated the contribution of APN/CD13 to the regulation of growth and survival processes in AML cells in vitro. Anti-CD13 monoclonal antibodies MY7 and SJ1D1 (which do not inhibit APN activity) and WM15 (an APN-blocking antibody) inhibited the growth of the AML cell line U937 and induced apoptosis, as evidenced by cell accumulation in the sub-G(1) phase, DNA fragmentation, and phosphatidylserine externalization. Isotype-matched IgG1 and the APN/CD13 enzymatic inhibitors bestatin and 2',3-dinitroflavone-8-acetic acid, were ineffective. Internalization of CD13-MY7 complex into cells was followed by mitochondrial membrane depolarization, Bcl-2 and Mcl-1 down-regulation, Bax up-regulation, caspase-9, caspase-8, and caspase-3 activation, and cleavage of the caspase substrate PARP-1. The broad-spectrum caspase inhibitor Z-VAD-fmk and the caspase-9- and caspase-8-specific inhibitors significantly attenuated apoptosis. CD13 ligation also induced apoptosis and PARP-1 cleavage in primary AML blasts, whereas normal blood cells were not affected. Overall, these data provide new evidence that CD13 can serve as a target for inducing caspase-dependent apoptosis in AML (independently of its APN activity). These findings may have implications for tumor biology and treatment.
authors.affiliation: Centre de Recherche des Cordeliers, Institut National de la Santé et de la Recherche Médicale (INSERM) U872, Paris, France.
authors.forename: Marion
authors.initials: M
authors.lastname: Piedfer
authors.forename: Daniel
authors.initials: D
authors.lastname: Dauzonne
authors.forename: Ruoping
authors.initials: R
authors.lastname: Tang
authors.forename: Juliette
authors.initials: J
authors.lastname: N'Guyen
authors.forename: Christian
authors.initials: C
authors.lastname: Billard
authors.forename: Brigitte
authors.initials: B
authors.lastname: Bauvois
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D018826:CD13 Antigens / Q000037:antagonists & inhibitors* / Q000276:immunology / Q000502:physiology; D020169:Caspases / Q000378:metabolism; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D015470:Leukemia, Myeloid, Acute / Q000201:enzymology* / Q000473:pathology* / Q000628:therapy; D048369:MAP Kinase Kinase 1 / Q000037:antagonists & inhibitors; D008297:Male; D053078:Membrane Potential, Mitochondrial; D008875:Middle Aged; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D000081082:Phosphoinositide-3 Kinase Inhibitors; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases / Q000378:metabolism; D011480:Protease Inhibitors / Q000494:pharmacology; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D020298:U937 Cells; D055815:Young Adult; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; C494826:BAX protein, human; D004791:Enzyme Inhibitors; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011480:Protease Inhibitors; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; C499320:PARP1 protein, human; D000071137:Poly (ADP-Ribose) Polymerase-1; D011065:Poly(ADP-ribose) Polymerases; D051057:Proto-Oncogene Proteins c-akt; D048369:MAP Kinase Kinase 1; C482125:MAP2K1 protein, human; D018826:CD13 Antigens; D020169:Caspases