title: Motility, proliferation, and egress to the circulation of human AML cells are elastase dependent in NOD/SCID chimeric mice.
abstract: The role of the proteolytic enzyme elastase in motility and proliferation of leukemic human acute myeloblastic leukemia (AML) cells is currently unknown. We report a correlation between abnormally high levels of elastase in the blood of AML patients and the number of leukemic blast cells in the circulation. In AML cells, we observed expression of cell-surface elastase, which was regulated by the chemokine stromal cell-derived factor-1 (SDF-1). In vitro inhibition of elastase prevented SDF-1-induced cell polarization, podia formation, and reduced migration of human AML cells as well as their adhesion. Elastase inhibition also significantly impaired in vivo homing of most human AML cells to the bone marrow (BM) of nonobese diabetic-severe combined immunodeficient (NOD/SCID)/beta-2 microglobulin knock-out (B2m null) mice that underwent transplantation. Moreover, in vitro proliferation of AML cells was elastase dependent. In contrast, treatment with elastase inhibitor enhanced the proliferation rate of human cord blood CD34+ cells, including primitive CD34+/CD38- cells, and their in vivo homing. Finally, NOD/SCID mice previously engrafted with human AML cells and treated with elastase inhibitor had significantly reduced egress of leukemic cells into the circulation. Taken together, our data demonstrate that human AML cells constitutively secrete and express SDF-1-dependent cell-surface elastase, which regulates their migration and proliferation.
authors.affiliation: Weizmann Institute of Science, Department of Immunology, PO Box 26, Rehovot, 76100, Israel.
authors.forename: Sigal
authors.initials: S
authors.lastname: Tavor
authors.forename: Isabelle
authors.initials: I
authors.lastname: Petit
authors.forename: Svetlana
authors.initials: S
authors.lastname: Porozov
authors.forename: Polina
authors.initials: P
authors.lastname: Goichberg
authors.forename: Abraham
authors.initials: A
authors.lastname: Avigdor
authors.forename: Sari
authors.initials: S
authors.lastname: Sagiv
authors.forename: Arnon
authors.initials: A
authors.lastname: Nagler
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Naparstek
authors.forename: Tsvee
authors.initials: T
authors.lastname: Lapidot
mesh_terms: D000208:Acute Disease; D000818:Animals; D001769:Blood; D002465:Cell Movement; D016764:Cell Polarity; D049109:Cell Proliferation; D054377:Chemokine CXCL12; D019743:Chemokines, CXC / Q000502:physiology; D005312:Fetal Blood / Q000166:cytology; D006801:Humans; D007951:Leukemia, Myeloid / Q000201:enzymology* / Q000473:pathology*; D019272:Leukocyte Elastase / Q000502:physiology*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D009368:Neoplasm Transplantation; D011554:Pseudopodia; D014183:Transplantation, Heterologous
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D019743:Chemokines, CXC; C515256:Cxcl12 protein, mouse; D019272:Leukocyte Elastase