FLT3-ITD transduces autonomous growth signals during its biosynthetic trafficking in acute myelogenous leukemia cells
FLT3-ITD transduces autonomous growth signals during its biosynthetic trafficking in acute myelogenous leukemia cells
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FLT3-ITD 在急性髓系白血病细胞的生物合成运输过程中转导自主生长信号
DOI：
10.1101/2021.01.01.424454
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发表时间：
2021
期刊：
影响因子：
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通讯作者：
Obata Yuuki
中科院分区：
文献类型：
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作者：
Yamawaki Kouhei;Shiina Isamu;Murata Takatsugu;Tateyama Satoru;Maekawa Yutarou;Niwa Mariko;Shimonaka Motoyuki;Okamoto Koji;Suzuki Toshihiro;Nishida Toshirou;Abe Ryo;Obata Yuuki
造血细胞中的fms样酪氨酸激酶3 （FLT3）在质膜上与其配体结合，然后转导生长信号。在30-40%的急性髓性白血病（AML）患者中发现flt3基因改变导致该激酶具有永久活性形式，如内部串联重复（ITD）和d835y替代。因此，针对FLT3突变体的分子靶向药物已被开发用于治疗AML。一些研究小组报道，与野生型FLT3 （FLT3-wt）相比，FLT3突变体保留在细胞器中，导致受体的PM定位水平较低。然而，突变体FLT3的精确亚细胞定位仍不清楚，致癌信号传导与错误定位之间的关系也未完全了解。在这项研究中，我们发现在白血病患者建立的细胞系中，内源性FLT3-ITD而不是FLT3-wt明显积聚在核周区域。我们的共免疫荧光实验表明，高尔基体标记与核周区共定位，表明AML细胞中FLT3-ITD主要定位在高尔基体区。FLT3-ITD以生物合成的方式运输到高尔基体，并以依赖于酪氨酸激酶活性的方式留在那里。酪氨酸激酶抑制剂，如quizartinib （AC220）和midostoin (PKC412)，可显著降低FLT3-ITD保留并增加突变体的PM水平。FLT3-ITD在其生物合成运输过程中激活下游内质网和高尔基体。我们的运输抑制剂治疗分析结果显示，内质网中的FLT3-ITD激活STAT5，而高尔基体中的FLT3-ITD可以激活AKT和ERK。我们提供的证据表明，在AML细胞中，FLT3-ITD信号在到达PM之前从早期分泌室发出。
FMS-like tyrosine kinase 3 (FLT3) in hematopoietic cells binds to its ligand at the plasma membrane (PM), then transduces growth signals.FLT3gene alterations that lead the kinase to assume its permanently active form, such asinternal tandem duplication (ITD)andD835Ysubstitution, are found in 30–40% of acute myelogenous leukemia (AML) patients. Thus, drugs for molecular targeting of FLT3 mutants have been developed for the treatment of AML. Several groups have reported that compared with wild-type FLT3 (FLT3-wt), FLT3 mutants are retained in organelles, resulting in low levels of PM localization of the receptor. However, the precise subcellular localization of mutant FLT3 remains unclear, and the relationship between oncogenic signaling and the mislocalization is not completely understood. In this study, we show that in cell lines established from leukemia patients, endogenous FLT3-ITD but not FLT3-wt clearly accumulates in the perinuclear region. Our co-immunofluorescence assays demonstrate that Golgi markers are co-localized with the perinuclear region, indicating that FLT3-ITD mainly localizes to the Golgi region in AML cells. FLT3-ITD biosynthetically traffics to the Golgi apparatus and remains there in a manner dependent on its tyrosine kinase activity. Tyrosine kinase inhibitors, such as quizartinib (AC220) and midostaurin (PKC412), markedly decrease FLT3-ITD retention and increase PM levels of the mutant. FLT3-ITD activates downstream in the endoplasmic reticulum (ER) and the Golgi apparatus during its biosynthetic trafficking. Results of our trafficking inhibitor treatment assays show that FLT3-ITD in the ER activates STAT5, whereas that in the Golgi can cause the activation of AKT and ERK. We provide evidence that FLT3-ITD signals from the early secretory compartments before reaching the PM in AML cells.