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 May 2, 2016; First published March 28, 2016
Citation Information: J Clin Invest. 2016;126(5):1664-1678. https://doi.org/10.1172/JCI81516.
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Categories: 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 1

Hoxa9 and Meis1 cooperation in leukemogenesis: leukemic cell engraftment is supported by MEIS1.

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Hoxa9 and Meis1 cooperation in leukemogenesis: leukemic cell engraftmen...
(A) Comparison of the proliferation and colony-forming activities of H9M1 cells expressing (+) or lacking (–) Meis1. MEIS1 expression in H9M1 and HΔM cells was confirmed by Western blotting; blots are representative of 2 experiments. Cumulative numbers of H9M1 cells in liquid culture were counted. Means of the natural logarithm of cell numbers from 3 independent experiments are shown (*P < 0.05, 2-tailed Student’s t test). Colony numbers per 1,000 H9M1 cells in methylcellulose culture were measured, and representative culture plates are shown (3 experiments). (B) Leukemia-free survival of sublethally irradiated animals transplanted with 1 × 106 H9M1 cells are shown for H9M1 cells with (red line) or without (blue line) Meis1. (C) H9M1 cells in bone marrow 48 hours after transplantation were detected as an mKO-positive fraction by flow cytometry. A significant reduction of H9M1 cells in bone marrow was observed in animals transplanted with Meis1 KO cells. The number was restored by reintroduction of Meis1. Frequencies of mKO-positive cells in bone marrow are indicated as mean ± SEM of 3 independent experiments (**P < 0.01, 1-way ANOVA with Dunnett’s multiple comparison test). (D) Representative images of H9M1 cells in frozen bone marrow sections (3 experiments). DiO-stained H9M1 cells were detected, though they were absent in Meis1 KO mice, and were observed after Meis1 reintroduction into HΔM cells. Gr-1 is indicated by red fluoro-dye, and nuclei were counterstained with DAPI. Scale bar: 20 μm. (E) Engraftment activities were assessed by flow cytometry, which detected H9M1 or HΔM cells in bone marrow 2 weeks after transplantation as mKO-positive fractions. Data are representative of 3 independent experiments. (F) Coculture of H9M1 cells with OP9 cells. Cobblestone areas were established by H9M1 cells, but not by Meis1 KOs, and were restored by Meis1 reintroduction. Scale bar: 100 μm. Numbers of cobblestone areas (CFAs) are indicated as mean ± SEM of 3 independent experiments (**P < 0.01, 1-way ANOVA with Dunnett’s multiple comparison test).