MEIS1-mediated transactivation of synaptotagmin-like 1 promotes CXCL12/CXCR4 signaling and leukemogenesis
Takashi Yokoyama, … , Ruud Delwel, Takuro Nakamura
Takashi Yokoyama, … , Ruud Delwel, Takuro Nakamura
Published March 28, 2016
Citation Information: J Clin Invest. 2016;126(5):1664-1678. https://doi.org/10.1172/JCI81516.
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Research Article Oncology

MEIS1-mediated transactivation of synaptotagmin-like 1 promotes CXCL12/CXCR4 signaling and leukemogenesis

Abstract

The TALE-class homeoprotein MEIS1 specifically collaborates with HOXA9 to drive myeloid leukemogenesis. Although MEIS1 alone has only a moderate effect on cell proliferation in vitro, it is essential for the development of HOXA9-induced leukemia in vivo. Here, using murine models of leukemogenesis, we have shown that MEIS1 promotes leukemic cell homing and engraftment in bone marrow and enhances cell-cell interactions and cytokine-mediated cell migration. We analyzed global DNA binding of MEIS1 in leukemic cells as well as gene expression alterations in MEIS1-deficent cells and identified synaptotagmin-like 1 (Sytl1, also known as Slp1) as the MEIS1 target gene that cooperates with Hoxa9 in leukemogenesis. Replacement of SYTL1 in MEIS1-deficent cells restored both cell migration and engraftment. Further analysis revealed that SYTL1 promotes cell migration via activation of the CXCL12/CXCR4 axis, as SYTL1 determines intracellular trafficking of CXCR4. Together, our results reveal that MEIS1, through induction of SYTL1, promotes leukemogenesis and supports leukemic cell homing and engraftment, facilitating interactions between leukemic cells and bone marrow stroma.

Authors

Takashi Yokoyama, Mayuka Nakatake, Takeshi Kuwata, Arnaud Couzinet, Ryo Goitsuka, Shuichi Tsutsumi, Hiroyuki Aburatani, Peter J.M. Valk, Ruud Delwel, Takuro Nakamura

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Figure 5

SYTL1 functions in human AML.

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SYTL1 functions in human AML. (A) SYTL1 silencing inhibits homing of RS...
(A) SYTL1 silencing inhibits homing of RS4;11 AML cells in NOD/SCID mice. Bone marrow samples were analyzed for the human CD45-positive fraction by flow cytometry (representative of 3 experiments). Data are compared between shSYTL1-treated (shSytl1 #4 and #5) and control shRNA (negative control) RS4;11 cells. Efficiencies of SYTL1 silencing were confirmed by RT-PCR. GAPDH, which was run on a separate gel, is shown as a loading control of cDNA. (B) SYTL1 silencing inhibits engraftment of RS4;11 AML cells in NOD/SCID mice. Bone marrow samples were analyzed for the human CD45-positive fraction by flow cytometry (n = 3). SYTL1 knockdown by shSYTL1 was confirmed by immunoblotting; blots are representative of 3 independent experiments. (A and B) Frequencies of human CD45-positive cells in bone marrow are indicated (mean ± SEM). (C) Survival curve of NOD/SCID mice transplanted with RS4;11 cells with shSYTL1 lentiviral vectors or empty vector. (D) Suppression of cell migration by SYTL1 knockdown. RS4;11 cells were transduced with lentiviral vectors bearing shSYTL1, and frequencies of cell migration were examined in the presence or absence of CXCL12. Data represent mean ± SEM of 3 independent experiments. (E) Pairwise correlations between gene expression profiles of 526 AML samples hybridized to the Affymetrix HGU 133Plus 2.0 GeneChips identified subsets with high SYTL1, HOXA9, HOXA7, and MEIS1 expression levels. The bar next to each sample indicates AML with the following genetic mutations in red: A: t(8;21), B: t(15;17), C: inv(16), D: CEBPA double mutation, E: CEBPA single mutation, F: NPM1 mutation, and G: 11q23 abnormalities/MLL fusions. Histograms next to the bar indicate expression levels of the following: 1: SYTL1, 2: HOXA9, 3: HOXA7, 4: MEIS1. Correlation coefficients were 0.33, 0.32, and 0.40 between SYTL1 and HOXA9, HOXA7, and MEIS1, respectively. An inset is enlarged to show two subsets of MLL-associated AML. I: BREhiEVI1lo, II: BREloEVI1hi. (A, B, and D) **P < 0.01, 1-way ANOVA with Dunnett’s multiple comparison test.