Inhibition of USP9X induces apoptosis in FLT3-ITD-positive AML cells cooperatively by inhibiting the mutant kinase through aggresomal translocation and inducing oxidative stress
Inhibition of USP9X induces apoptosis in FLT3-ITD-positive AML cells cooperatively by inhibiting the mutant kinase through aggresomal translocation and inducing oxidative stress
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DOI：
10.1016/j.canlet.2019.03.046
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发表时间：
2019-01-01
期刊：
影响因子：
9.7
通讯作者：
Miura, Osamu
中科院分区：
文献类型：
--
作者：
Akiyama, Hiroki;Umezawa, Yoshihiro;Miura, Osamu
FLT 3-ITD和FLT 3-TKD是急性髓细胞白血病（AML）中最常见的突变，前者与预后不良相关。在这里，我们发现去泛素化酶USP 9 X通过其抑制剂WP 1130或EOAI 3402143（G9）的抑制优先诱导由这些突变激酶转化的细胞的凋亡，包括FLT 3-ITD阳性AML细胞系MV 4 -11和原代AML细胞。在机制上，WP 1130诱导突变激酶的侵袭性易位，特别是处于其活化和自磷酸化构象的FLT 3-ITD，以阻断下游信号传导事件，这通过USP 9 X的敲低而加剧。此外，USP 9 X与FLT 3-ITD物理结合以抑制其K63连接的多聚泛素化，而FLT 3-ITD通过泛素/蛋白酶体途径诱导USP 9 X的酪氨酸磷酸化和降解。WP 1130或G9还诱导氧化应激，以刺激应激相关的MAP激酶途径和DNA损伤反应，与抑制FLT 3-ITD信号传导合作激活线粒体介导的内在细胞凋亡途径，该途径通过BH 3模拟物协同增强，并通过Bcl-xL或Mcl-1的过表达来预防。因此，USP 9 X代表了治疗耐药性FLT 3-ITD阳性AML的新疗法的有希望的靶标。
FLT3-ITD and FLT3-TKD are the most frequent mutations in acute myeloid leukemia (AML) with the former associated with a poor prognosis. Here we show that inhibition of the deubiquitinase USP9X by its inhibitor WP1130 or EOAI3402143 (G9) induces apoptosis preferentially in cells transformed by these mutant kinases, including FLT3-ITD-positive AML cell line MV4-11 and primary AML cells. Mechanistically, WP1130 induced aggresomal translocation of the mutant kinases, particularly FLT3-ITD in its activated and autophosphorylated conformation, to block the downstream signaling events, which was aggravated by knock down of USP9X. Moreover, USP9X physically associated with FLT3-ITD to inhibit its K63-linked polyubiquitination, while FLT3-ITD induced tyrosine phosphorylation and degradation of USP9X through the ubiquitin/proteasome pathway. WP1130 or G9 also induced oxidative stress to stimulate stress-related MAP kinase pathways and DNA damage responses to activate in cooperation with inhibition of FLT3-ITD signaling the intrinsic mitochondria-mediated apoptotic pathway, which was synergistically enhanced by BH3 mimetics and prevented by overexpression of Bcl-xL or Mcl-1. Thus, USP9X represents a promising target for novel therapies against therapy-resistant FLT3-ITD-positive AML.