title: Pim-1 kinase phosphorylates and stabilizes 130 kDa FLT3 and promotes aberrant STAT5 signaling in acute myeloid leukemia with FLT3 internal tandem duplication.
abstract: The type III receptor tyrosine kinase fms-like tyrosine kinase 3 (FLT3) is expressed on both normal hematopoietic stem cells and acute myeloid leukemia (AML) cells and regulates their proliferation. Internal tandem duplication (ITD) mutation of FLT3 is present in a third of AML cases, results in constitutive activation and aberrant signaling of FLT3, and is associated with adverse treatment outcomes. While wild-type (WT) FLT3 is predominantly a 150 kDa complex glycosylated cell surface protein, FLT3-ITD is partially retained in the endoplasmic reticulum as a 130 kDa underglycosylated species associated with the chaperones calnexin and heat shock protein (HSP) 90, and mediates aberrant STAT5 signaling, which upregulates the oncogenic serine/threonine kinase Pim-1. FLT3 contains a Pim-1 substrate consensus serine phosphorylation site, and we hypothesized that it might be a Pim-1 substrate. Pim-1 was indeed found to directly interact with and serine-phosphorylate FLT3. Pim-1 inhibition decreased the expression and half-life of 130 kDa FLT3, with partial abrogation by proteasome inhibition, in association with decreased FLT3 binding to calnexin and HSP90, and increased 150 kDa FLT3 expression and half-life, with abrogation by inhibition of glycosylation. These findings were consistent with Pim-1 stabilizing FLT3-ITD as a 130 kDa species associated with calnexin and HSP90 and inhibiting its glycosylation to form the 150 kDa species. Pim-1 knockdown effects were similar. Pim-1 inhibition also decreased phosphorylation of FLT3 at tyrosine 591 and of STAT5, and expression of Pim-1 itself, consistent with inhibition of the FLT3-ITD-STAT5 signaling pathway. Finally, Pim-1 inhibition synergized with FLT3 inhibition in inducing apoptosis of FLT3-ITD cells. This is, to our knowledge, the first demonstration of a role of Pim-1 in a positive feedback loop promoting aberrant signaling in malignant cells.
authors.affiliation: Greenebaum Cancer Center, University of Maryland, Baltimore, Maryland, United States of America.
authors.forename: Karthika
authors.initials: K
authors.lastname: Natarajan
authors.forename: Yingqiu
authors.initials: Y
authors.lastname: Xie
authors.forename: Mehmet
authors.initials: M
authors.lastname: Burcu
authors.forename: Douglas E
authors.initials: DE
authors.lastname: Linn
authors.forename: Yun
authors.initials: Y
authors.lastname: Qiu
authors.forename: Maria R
authors.initials: MR
authors.lastname: Baer
mesh_terms: D000818:Animals; D017209:Apoptosis; D037281:Calnexin / Q000378:metabolism; D002460:Cell Line; D049109:Cell Proliferation; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006031:Glycosylation; D006360:Heat-Shock Proteins / Q000378:metabolism; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000378:metabolism*; D051379:Mice; D009154:Mutation; D010766:Phosphorylation; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D051573:Proto-Oncogene Proteins c-pim-1 / Q000378:metabolism*; D050799:STAT5 Transcription Factor / Q000378:metabolism*; D012694:Serine / Q000378:metabolism; D015398:Signal Transduction; D014443:Tyrosine / Q000378:metabolism; D051941:fms-Like Tyrosine Kinase 3 / Q000378:metabolism*
chemical_list: D006360:Heat-Shock Proteins; D050799:STAT5 Transcription Factor; D037281:Calnexin; D014443:Tyrosine; D012694:Serine; C497970:FLT3 protein, human; D051941:fms-Like Tyrosine Kinase 3; D051573:Proto-Oncogene Proteins c-pim-1; D046988:Proteasome Endopeptidase Complex
references.citation: Mol Cancer Res. 2005 Mar;3(3):170-81
references.pmid: 15798097
references.citation: Cell. 1984 May;37(1):141-50
references.pmid: 6327049
references.citation: J Clin Oncol. 2010 Apr 10;28(11):1856-62
references.pmid: 20212254
references.citation: J Mol Biol. 2013 Jan 23;425(2):411-23
references.pmid: 23142567
references.citation: Mol Cancer Res. 2007 Sep;5(9):909-22
references.pmid: 17855660
references.citation: Cancer Res. 2008 Sep 15;68(18):7409-18
references.pmid: 18794129
references.citation: Annu Rev Biochem. 2011;80:825-58
references.pmid: 21391816
references.citation: Proc Natl Acad Sci U S A. 2008 Sep 16;105(37):13889-94
references.pmid: 18784362
references.citation: FEBS Lett. 2004 Jul 30;571(1-3):43-9
references.pmid: 15280015
references.citation: Blood. 2005 Feb 15;105(4):1759-67
references.pmid: 15498859
references.citation: Proc Natl Acad Sci U S A. 2007 Jun 19;104(25):10470-5
references.pmid: 17563366
references.citation: Br J Haematol. 2007 Sep;138(5):603-15
references.pmid: 17686054
references.citation: J Biol Chem. 2008 Feb 8;283(6):3349-3356
references.pmid: 18056989
references.citation: Mol Pharmacol. 2010 Aug;78(2):310-8
references.pmid: 20460432
references.citation: Blood. 2009 Apr 9;113(15):3568-76
references.pmid: 19204327
references.citation: Mol Cancer Ther. 2007 Jan;6(1):163-72
references.pmid: 17218638
references.citation: Leukemia. 2003 Jan;17(1):120-4
references.pmid: 12529668
references.citation: Blood. 2006 Aug 15;108(4):1339-45
references.pmid: 16627759
references.citation: EMBO J. 1991 Mar;10(3):655-64
references.pmid: 1825810
references.citation: Cancer Res. 2004 May 15;64(10):3645-52
references.pmid: 15150124
references.citation: Curr Opin Hematol. 2011 Mar;18(2):71-6
references.pmid: 21245757
references.citation: Oncogene. 2008 Aug 14;27(35):4809-19
references.pmid: 18438430
references.citation: Biochem Cell Biol. 1997;75(2):153-62
references.pmid: 9250363
references.citation: Mol Cell Biol. 2005 May;25(9):3690-703
references.pmid: 15831474
references.citation: Br J Haematol. 2006 Sep;134(5):500-9
references.pmid: 16869825
references.citation: J Biol Chem. 2005 Feb 18;280(7):6130-7
references.pmid: 15525646
references.citation: Blood. 2009 Oct 1;114(14):2984-92
references.pmid: 19654408
references.citation: Leukemia. 2002 Aug;16(8):1535-40
references.pmid: 12145695
references.citation: Leuk Res. 2012 Feb;36(2):224-31
references.pmid: 21802138
references.citation: Blood. 2011 Jul 21;118(3):693-702
references.pmid: 21628411
references.citation: J Clin Oncol. 2010 Oct 1;28(28):4339-45
references.pmid: 20733134
references.citation: Proc Natl Acad Sci U S A. 2002 Feb 19;99(4):2175-80
references.pmid: 11854514
references.citation: Blood. 2011 Mar 24;117(12):3294-301
references.pmid: 21270442
references.citation: J Biol Chem. 1999 Jun 25;274(26):18659-66
references.pmid: 10373478
references.citation: Mol Cell Biol. 2004 Jul;24(13):6104-15
references.pmid: 15199164
references.citation: J Exp Med. 2009 Aug 31;206(9):1957-70
references.pmid: 19687226
references.citation: Blood. 2002 Sep 1;100(5):1532-42
references.pmid: 12176867
references.citation: Blood. 2012 Feb 16;119(7):1791-2
references.pmid: 22343664
references.citation: J Biol Chem. 2005 Dec 16;280(50):41675-82
references.pmid: 16227208
references.citation: Cancer Res. 2008 Jul 1;68(13):5076-85
references.pmid: 18593906
references.citation: J Cell Biochem. 2008 Nov 1;105(4):1048-58
references.pmid: 18767071
references.citation: Cancer Res. 2006 Apr 1;66(7):3828-35
references.pmid: 16585210
references.citation: Blood. 2002 Jan 1;99(1):310-8
references.pmid: 11756186
references.citation: Prog Nucleic Acid Res Mol Biol. 2003;73:107-36
references.pmid: 12882516
references.citation: Mol Cell. 2009 Oct 23;36(2):326-39
references.pmid: 19854140
references.citation: Int J Biochem Cell Biol. 2006 Mar;38(3):430-43
references.pmid: 16356754
references.citation: Clin Cancer Res. 2009 Jul 1;15(13):4263-9
references.pmid: 19549778
references.citation: J Biol Chem. 2011 Sep 2;286(35):30263-30273
references.pmid: 21768087