title: The apoptotic mechanism of action of the sphingosine kinase 1 selective inhibitor SKI-178 in human acute myeloid leukemia cell lines.
abstract: We previously developed SKI-178 (N'-[(1E)-1-(3,4-dimethoxyphenyl)ethylidene]-3-(4-methoxxyphenyl)-1H-pyrazole-5-carbohydrazide) as a novel sphingosine kinase-1 (SphK1) selective inhibitor and, herein, sought to determine the mechanism-of-action of SKI-178-induced cell death. Using human acute myeloid leukemia (AML) cell lines as a model, we present evidence that SKI-178 induces prolonged mitosis followed by apoptotic cell death through the intrinsic apoptotic cascade. Further examination of the mechanism of action of SKI-178 implicated c-Jun NH2-terminal kinase (JNK) and cyclin-dependent protein kinase 1 (CDK1) as critical factors required for SKI-178-induced apoptosis. In cell cycle synchronized human AML cell lines, we demonstrate that entry into mitosis is required for apoptotic induction by SKI-178 and that CDK1, not JNK, is required for SKI-178-induced apoptosis. We further demonstrate that the sustained activation of CDK1 during prolonged mitosis, mediated by SKI-178, leads to the simultaneous phosphorylation of the prosurvival Bcl-2 family members, Bcl-2 and Bcl-xl, as well as the phosphorylation and subsequent degradation of Mcl-1. Moreover, multidrug resistance mediated by multidrug-resistant protein1 and/or prosurvival Bcl-2 family member overexpression did not affect the sensitivity of AML cells to SKI-178. Taken together, these findings highlight the therapeutic potential of SKI-178 targeting SphK1 as a novel therapeutic agent for the treatment of AML, including multidrug-resistant/recurrent AML subtypes.
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Taryn E
authors.initials: TE
authors.lastname: Dick
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Jeremy A
authors.initials: JA
authors.lastname: Hengst
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Todd E
authors.initials: TE
authors.lastname: Fox
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Ashley L
authors.initials: AL
authors.lastname: Colledge
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Vijay P
authors.initials: VP
authors.lastname: Kale
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Shen-Shu
authors.initials: SS
authors.lastname: Sung
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Arun
authors.initials: A
authors.lastname: Sharma
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Shantu
authors.initials: S
authors.lastname: Amin
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Loughran
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Mark
authors.initials: M
authors.lastname: Kester
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia.
authors.forename: Hong-Gang
authors.initials: HG
authors.lastname: Wang
authors.affiliation: Department of Pharmacology (T.E.D., J.A.H., A.L.C., V.P.K., S.-S.S., A.S., S.A., H.-G.W., J.K.Y.) and The Jake Gittlen Laboratories for Cancer Research (T.E.D., J.A.H., A.L.C., V.P.K., J.K.Y.), The Pennsylvania State University College of Medicine, Hershey, Pennsylvania; and Department of Pharmacology (T.E.F., M.K.), and University of Virginia Cancer Center (T.P.L.), University of Virginia, Charlottesville, Virginia jky1@psu.edu.
authors.forename: Jong K
authors.initials: JK
authors.lastname: Yun
mesh_terms: D017209:Apoptosis / Q000187:drug effects / Q000502:physiology*; D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D018922:HL-60 Cells; D006801:Humans; D006834:Hydrazines / Q000494:pharmacology* / Q000627:therapeutic use; D015470:Leukemia, Myeloid, Acute / Q000188:drug therapy / Q000201:enzymology*; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D011720:Pyrazoles / Q000494:pharmacology* / Q000627:therapeutic use; D020298:U937 Cells; D000099157:Sphingosine Kinase
chemical_list: D006834:Hydrazines; D017853:Phosphotransferases (Alcohol Group Acceptor); D011720:Pyrazoles; D000099157:Sphingosine Kinase; C556358:N'-((1E)-1-(3,4-dimethoxyphenyl)ethylidene)-3-(4-methoxyphenyl)-1H-pyrazole-5-carbohydrazide