Internal Tandem Duplication Mutations in FLT3 Gene Augment Chemotaxis to Cxcl12 Protein by Blocking the Down-regulation of the Rho-associated Kinase via the Cxcl12/Cxcr4 Signaling Axis*
Internal Tandem Duplication Mutations in FLT3 Gene Augment Chemotaxis to Cxcl12 Protein by Blocking the Down-regulation of the Rho-associated Kinase via the Cxcl12/Cxcr4 Signaling Axis*
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DOI：
10.1074/jbc.m114.568287
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发表时间：
2014-09
期刊：
影响因子：
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通讯作者：
Chie Onish;Satomi Mori-Kimachi;T. Hirade;Mariko Abe;T. Taketani;J. Suzumiya;T. Sugimoto;S. Yamaguchi;R. Kapur;S. Fukuda
中科院分区：
文献类型：
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作者：
Chie Onish;Satomi Mori-Kimachi;T. Hirade;Mariko Abe;T. Taketani;J. Suzumiya;T. Sugimoto;S. Yamaguchi;R. Kapur;S. Fukuda
背景：ITD-FLT 3突变诱导AML患者的难治性表型，并增强细胞向Cxcl 12的迁移。结果：ITD-FLT 3通过抑制Rho相关激酶的下调，促进细胞向Cxcl 12的迁移。结论：ITD-FLT 3通过调节Rho相关激酶的表达增强Cxcl 12诱导的细胞迁移。意义：Rho相关激酶可用于治疗ITD-FLT 3 + AML患者。Flt 3基因（ITD-FLT 3）的内部串联重复突变增强了细胞向趋化因子Cxcl 12的迁移，Cxcl 12在治疗保护性骨髓小生境中高度表达，为ITD-FLT 3+急性髓性白血病的不良预后提供了潜在的机制。我们的目的是研究ITD-FLT 3与增加细胞向Cxcl 12迁移的机制。对ITD-FLT 3+细胞中Cxcl 12调节基因表达的分类表明，ITD-FLT 3+细胞向Cxcl 12迁移的增强与Cxcl 12/Cxcr 4下游基因的差异表达相关，这些基因在功能上与ITD-FLT 3 −细胞中表达的基因不同，但与Cxcr 4表达水平无关。在这些差异调节基因中，Rock 1在向Cxcl 12迁移的ITD-FLT 3+细胞中的表达显著高于向Cxcl 12迁移的ITD-FLT 3 −细胞。在ITD-FLT 3 −细胞中，Rock 1表达和Mypt 1磷酸化短暂上调，但随后被Cxcl 12下调。相反，ITD-FLT 3的存在阻断了Cxcl 12诱导的Rock 1下调和早期Mypt 1去磷酸化。同样，FLT 3配体抵消了Cxcl 12诱导的ITD-FLT 3 −细胞中Rock 1的下调，这与细胞向Cxcl 12迁移的增强相一致。Rock 1拮抗剂或Rock 1 shRNA消除了ITD-FLT 3+细胞向Cxcl 12迁移的增强。我们的研究结果表明，ITD-FLT 3通过拮抗Rock 1表达的下调来增加细胞向Cxcl 12的迁移。这些发现表明，由ITD-FLT 3诱导的Rock 1表达和活性的异常调节可能增强急性髓性白血病细胞对治疗保护性骨髓小生境的趋化性，其中Cxcl 12大量表达。
Background: ITD-FLT3 mutations induce the refractory phenotype in patients with AML and enhance cell migration toward Cxcl12. Results: The enhanced cell migration toward Cxcl12 by ITD-FLT3 is mediated by inhibiting the down-regulation of Rho-associated kinase. Conclusion: ITD-FLT3 enhances Cxcl12-induced cell migration by modulating the expression of Rho-associated kinase. Significance: Rho-associated kinase may be therapeutically manipulated for the treatment of ITD-FLT3+ AML patients. Internal tandem duplication mutations in the Flt3 gene (ITD-FLT3) enhance cell migration toward the chemokine Cxcl12, which is highly expressed in the therapy-protective bone marrow niche, providing a potential mechanism underlying the poor prognosis of ITD-FLT3+ acute myeloid leukemia. We aimed to investigate the mechanisms linking ITD-FLT3 to increased cell migration toward Cxcl12. Classification of the expression of Cxcl12-regulated genes in ITD-FLT3+ cells demonstrated that the enhanced migration of ITD-FLT3+ cells toward Cxcl12 was associated with the differential expression of genes downstream of Cxcl12/Cxcr4, which are functionally distinct from those expressed in ITD-FLT3− cells but are independent of the Cxcr4 expression levels. Among these differentially regulated genes, the expression of Rock1 in the ITD-FLT3+ cells that migrated toward Cxcl12 was significantly higher than in ITD-FLT3− cells that migrated toward Cxcl12. In ITD-FLT3− cells, Rock1 expression and Mypt1 phosphorylation were transiently up-regulated but were subsequently down-regulated by Cxcl12. In contrast, the presence of ITD-FLT3 blocked the Cxcl12-induced down-regulation of Rock1 and early Mypt1 dephosphorylation. Likewise, the FLT3 ligand counteracted the Cxcl12-induced down-regulation of Rock1 in ITD-FLT3− cells, which coincided with enhanced cell migration toward Cxcl12. Rock1 antagonists or Rock1 shRNA abolished the enhanced migration of ITD-FLT3+ cells toward Cxcl12. Our findings demonstrate that ITD-FLT3 increases cell migration toward Cxcl12 by antagonizing the down-regulation of Rock1 expression. These findings suggest that the aberrant modulation of Rock1 expression and activity induced by ITD-FLT3 may enhance acute myeloid leukemia cell chemotaxis to the therapy-protective bone marrow niche, where Cxcl12 is abundantly expressed.