This study investigated the effect of using small interfering RNA (siRNA) to silence the wild-type FMS-like tyrosine kinase 3 (FLT3) gene in acute myeloid leukaemia (AML) cells, in vitro and in vivo. FLT3 siRNA was introduced into the human AML cell line, THP1, and into a THP1 xenograft tumour model in BALB/c nude mice. FLT3 siRNA effectively reduced both the mRNA and the protein levels of FLT3, arrested cells in G0/G1 phase, inhibited THP1 cell proliferation and increased apoptosis. Intraperitoneal injection of FLT3 siRNA suppressed tumour growth in BALB/c nude mice. FLT3 siRNA treatment also reduced cyclin D1 and Bcl-2 protein levels, and increased the nuclear level of silencing mediator for retinoic acid and thyroid hormone receptors protein both in vitro and in vivo. These data suggest that FLT3 siRNA is a strong inhibitor of FLT3 expression in vitro and in vivo, and may provide a new therapeutic target for AML.
LarsonRALe BeauMM: Therapy-related myeloid leukaemia: A model for leukemogenesis in humans. Chem Biol Interact2005; 153: 187–195.
2.
ZhaiXWChengFWLeeV: Improved survival outcome of childhood acute myeloid leukemia with intensified chemotherapy in Chinese children. Pediatr Hematol Oncol2011; 28: 269–278.
3.
ThomtonKALevisM: FLT3 mutation and acute myelogenous leukemia with leukostasis. N Engl J Med2007; 357: 1639.
4.
MeshinchiSArceciRJSandersJE: Role of allogeneic stem cell transplantation in FLT3/ITD-positive AML. Blood2006; 108: 400–401.
5.
CarowCELevensteinMKaufmannSH: Expression of the hematopoietic growth factor receptor FLT3 (STK-1/Flk2) in human leukemias. Blood1996; 87: 1089–1096.
6.
AdvaniAS: FLT3 and acute myelogenous leukemia: biology, clinical significance and therapeutic applications. Curr Pharm Des2005; 11: 3449–3457.
7.
BelsonMKingsleyBHolmesA: Risk factors for acute leukemia in children: A review. Environ Health Perspect2007; 115: 138–145.
8.
KottaridisPDGaleRELangabeerSE: Studies of FLT3 mutations in paired presentation and relapse samples from patients with acute myeloid leukemia: implications for the role of FLT3 mutations in leukemogenesis, minimal residual disease detection, and possible therapy with FLT3 inhibitors. Blood2002; 100: 2393–2398.
9.
ThiedeCSteudelCMohrB: Analysis of FLT3 activating mutations in 979 patients with acute myelogenous leukemia: association with FAB subtypes and identification of subgroups with poor prognosis. Blood2002; 99: 4326–4335.
10.
BrownPSmallD: FLT3 inhibitors: A paradigm for the development of targeted therapeutics for paediatric cancer. Eur J Cancer2004; 40: 707–724.
11.
GilesFJStopeckATSilvermanLR: SU5416, a small molecule tyrosine kinase receptor inhibitor, has biologic activity in patients with refractory acute myeloid leukemia or myelodysplastic syndromes. Blood2003; 102: 795–801.
12.
SmithBDLevisMBeranM: Single-agent CEP-701, a novel LT3 inhibitor, shows biologic and clinical activity in patients with relapsed or refractory acute myeloid leukemia. Blood2004; 103: 3669–3676.
13.
FischerTStoneRMDeangeloDJ: Phase IIB trial of oral midostaurin (PKC412), the FMS-like tyrosine kinase 3 receptor (FLT3) and multi-targeted kinase inhibitor, in patients with acute myeloid leukemia and high-risk myelodysplastic syndrome with either wild-type or mutated FLT3. J Clin Oncol2010; 28: 4339–4345.
14.
LivakKSchmittgenT: Analysis of relative gene expression data using real-time quantitative PCR and the 2-ΔΔCt method. Methods2001; 25: 402–408.
15.
Committee for the Update of the Guide for the Care and Use of Laboratory Animals: Guide for the Care and Use of Laboratory Animals (NIH publication number 85–23). Washington DC: National Institutes of Health, 1985.
16.
KitamuraTItohMNodaT: Combined effects of cyclooxygenase-1 and cyclooxygenase-2 selective inhibitors on intestinal tumorigenesis in adenomatous polyposis coli gene knockout mice. Int J Cancer2004; 109: 576–580.
17.
RosnetOMatteïMGMarchettoS: Isolation and chromosomal localization of a novel FMS-like tyrosine kinase gene. Genomics1991; 9: 380–385.
18.
MatthewsWJordanCTWiegandGW: A receptor tyrosine kinase specific to hematopoietic stem and progenitor cell-enriched populations. Cell1991; 65: 1143–1152.
19.
RosnetOSchifCPébusqueMJ: Human FLT3/FLK2 gene: cDNA cloning and expression in hematopoietic cells. Blood1993; 82: 1110–1119.
20.
LymanSDJamesLZapponeJ: Characterization of the protein encoded by the flt3 (flk2) receptor-like tyrosine kinase gene. Oncogene1993; 8: 815–822.
21.
MarocNRottapelRRosnetO: Biochemical characterization and analysis of the transforming potential of the FLT3/FLK2 receptor tyrosine kinase. Oncogene1993; 8: 909–918.
22.
BrazelCYDucceschiMHPytowskiB: The FLT3 tyrosine kinase receptor inhibits neural stem/progenitor cell proliferation and collaborates with NGF to promote neuronal survival. Mol Cell Neurosci2001; 18: 381–393.
23.
MittonKPSwainPKKhannaH: Interaction of retinal bZIP transcription factor NRL with Flt3-interacting zinc-finger protein Fiz1: possible role of Fiz1 as a transcriptional repressor. Hum Mol Genet2003; 12: 365–373.
24.
ParcellsBWIkedaAKWaldripT Simms: FMS-like tyrosine kinase 3 in normal hematopoiesis and acute myeloid leukemia. Stem Cells2006; 24: 1174–1184.
25.
KuchenbauerFKernWSchochC: Detailed analysis of FLT3 expression levels in acute myeloid leukemia. Haematologica2005; 90: 1617–1625.
ChoudharyCMüller-TidowCBerdelWE: Signal transduction of oncogenic Flt3. Int J Hematol2005; 82: 93–99.
29.
Sino-US Shanghai Leukemia Cooperative Group: FLT3 gene mutation and its prognostic implication in patients with acute leukemia. Zhonghua Xue Ye Xue Za Zhi2010; 31: 1–5 [in Chinese, English abstract].
30.
WhitmanSPMaharryKRadmacherMD: FLT3 internal tandem duplication associates with adverse outcome and gene- and microRNA-expression signatures in patients 60 years of age or older with primary cytogenetically normal acute myeloid leukemia: A Cancer and Leukemia Group B study. Blood2010; 116: 3622–3626.
31.
ChanPM: Differential signaling of Flt3 activating mutations in acute myeloid leukemia: A working model. Protein Cell2011; 2: 108–115.
32.
WaltersDKStoffregenEPHeinrichMC: RNAi-induced down-regulation of FLT3 expression in AML cell lines increases sensitivity to MLN518. Blood2005; 105: 2952–2954.
33.
FilleurSCourtinAAit-Si-AliS: SiRNA-mediated inhibition of vascular endothelial growth factor severely limits tumor resistance to antiangiogenic thrombospondin-1 and slows tumor vascularization and growth. Cancer Res2003; 63: 3919–3922.
34.
CantrelCZachowskiAGenyB: Overexpression of the anti-apoptotic protein Bcl-2 affects membrane lipid composition in HL-60 cells. Lipids2009; 44: 499–509.
35.
KorolevaOATomlinsonMParinyapongP: CycD1, a putative G1 cyclin from Antirrhinum majus, accelerates the cell cycle in cultured tobacco BY-2 cells by enhancing both G1/S entry and progression through S and G2 phases. Plant Cell2004; 16: 2364–2379.
36.
StanyaKJKaoHY: New insights into the functions and regulation of the transcriptional corepressors SMRT and N-CoR. Cell Div2009; 4: 7.
37.
EvanGIVousdenKH: Proliferation, cell cycle and apoptosis in cancer. Nature2001; 411: 342–348.
38.
JungKHKimJKNohJH: Targeted disruption of Nemo-like kinase inhibits tumor cell growth by simultaneous suppression of cyclin D1 and CDK2 in human hepatocellular carcinoma. J Cell Biochem2010; 110: 687–696.
39.
KimJKJungKHNohJH: Targeted disruption of S100P suppresses tumor cell growth by down-regulation of cyclin D1 and CDK2 in human hepatocellular carcinoma. Int J Oncol2009; 35: 1257–1264.
ReedJC: Bcl-2-family proteins and hematologic malignancies: history and future prospects. Blood2008; 111: 3322–3330.
42.
WenCMaFTWanWQ: Expression of CREB/Bcl-2 in bone marrow mononuclear cells of children with acute leukemia. Zhongguo Dang Dai Er Ke Za Zhi2010; 12: 177–180 [in Chinese, English abstract].
43.
GuenovaMLBalatzenkoGNNikolovaVR: An anti-apoptotic pattern correlates with multidrug resistance in acute myeloid leukemia patients: A comparative study of active caspase-3, cleaved PARPs, Bcl-2, survivin and MDR1 gene. Hematology2010; 15: 135–143.
44.
JepsenKRosenfeldMG: Biological roles and mechanistic actions of co-repressor complexes. J Cell Sci2002; 115: 689–698.
45.
TakahashiSMcConnellMJHarigaeH: The Flt3 internal tandem duplication mutant inhibits the function of transcriptional repressors by blocking interactions with SMRT. Blood2004; 103: 4650–4658.
