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 3

Sytl1 is a MEIS1 transcriptional target in leukemogenesis.

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Sytl1 is a MEIS1 transcriptional target in leukemogenesis. (A) Schemati...
(A) Schematic diagram for target gene identification. (B) Sytl1 cooperated with Hoxa9 in leukemogenesis. Kaplan-Meier survival curves for recipient mice transplanted with Hoxa9-, Sytl1-, Hoxa9/Sytl1-, or Hoxa9/Meis1-transduced bone marrow cells. **P = 0.015, log-rank test. (C) ChIP-Seq analysis showed a MEIS1-binding peak 2 kb upstream of Sytl1. (D) Downregulation of Sytl1 by Meis1 KO in H9M1 cells. Representative gels of RT-PCR (3 experiments) and Q-RT-PCR (3 experiments) for Sytl1 mRNA expression and immunoblotting for the SYTL1 protein using α-SYTL1 in H9M1 (3 experiments). Immunoblotting for GAPDH and HA-MEIS1 proteins was performed on separate gels. Mean values of relative Sytl1 mRNA expression were normalized to Gapdh mRNA (**P < 0.01, 1-way ANOVA with Dunnett’s multiple comparison test). (E) Sytl1 expression was upregulated by Meis1 overexpression in 32Dcl3 cells. Sytl1 mRNA expression relative to Gapdh mRNA based upon Q-RT-PCR (n = 3, **P < 0.01, 2-tailed Student’s t test). (F) Luciferase reporter assay. A 2-kb fragment upstream of Sytl1 was introduced upstream of the luciferase cDNA. The mutant clone was created by introducing TGACAG to TGTTAG mutations into 3 putative MEIS1-binding sequences (MBS). Relative luciferase activities are shown in the presence or absence of MEIS1. Data represent mean ± SEM of 3 independent experiments (**P < 0.01, 2-tailed Student’s t test).