突变型FMS样酪氨酸激酶-3的选择性降解依赖于BIM介导的热休克蛋白耗竭

Selective degradation of mutant FMS-like tyrosine kinase-3 requires BIM-dependent depletion of heat shock proteins

LEUKEMIA

影响因子:13.4

分区:医学1区 Top / 血液学1区肿瘤学2区

发表日期:2024 Dec

作者: Melisa Halilovic, Mohamed Abdelsalam, Joanna Zabkiewicz, Michelle Lazenby, Caroline Alvares, Matthias Schmidt, Walburgis Brenner, Sara Najafi, Ina Oehme, Christoph Hieber, Yanira Zeyn, Matthias Bros, Wolfgang Sippl, Oliver H Krämer

DOI: 10.1038/s41375-024-02405-5

摘要

FMS样酪氨酸激酶-3（FLT3-ITD）内部串联重复突变在急性髓性白血病（AML）中常见。诱导突变FLT3蛋白酶体降解的蛋白质降解靶向嵌合体（PROTACs）作为一种创新的药理学策略逐渐出现。控制靶向蛋白降解的分子机制超越了泛素-蛋白酶体系统，目前已知唯一的FLT3降解剂类型是PROTACs。我们报道，基于Hippel-Lindau（VHL）泛素连接酶的FLT3 PROTAC MA49（melotinib-49）和疏水性标签分子MA50（halotinib-50）可以在内质网相关的肿瘤性FLT3-ITD中有效降解FLT3-ITD，但不影响野生型FLT3。纳摩尔浓度的MA49和MA50可诱导携带FLT3-ITD的人类白血病细胞系及原代AML细胞凋亡（p < 0.05-0.0001），而不影响原代造血干细胞、分化的免疫细胞、FLT3野生型细胞、视网膜细胞和c-KIT依赖细胞。在斑马鱼模型中验证了MA49对FLT3-ITD阳性白血病细胞的体内活性。降解剂导致FLT3-ITD丧失涉及促凋亡的BH3-蛋白BIM，并引发一种先前未被发现的降解剂诱导的蛋白折叠伴侣蛋白耗竭。HSP90和HSP110的表达水平与AML患者生存率降低显著相关（p < 0.1），HSP90、HSP110与FLT3在原代AML细胞中的表达呈正相关（p < 0.01）。HSP90抑制剂可阻止降解剂引发的FLT3-ITD消除，建立了机制性反馈回路。

Abstract

Internal tandem duplications in the FMS-like tyrosine kinase-3 (FLT3-ITD) are common mutations in acute myeloid leukemia (AML). Proteolysis-targeting chimeras (PROTACs) that induce proteasomal degradation of mutated FLT3 emerge as innovative pharmacological approach. Molecular mechanisms that control targeted proteolysis beyond the ubiquitin-proteasome-system are undefined and PROTACs are the only known type of FLT3 degraders. We report that the von-Hippel-Lindau ubiquitin-ligase based FLT3 PROTAC MA49 (melotinib-49) and the FLT3 hydrophobic tagging molecule MA50 (halotinib-50) reduce endoplasmic reticulum-associated, oncogenic FLT3-ITD but spare FLT3. Nanomolar doses of MA49 and MA50 induce apoptosis of human leukemic cell lines and primary AML blasts with FLT3-ITD (p < 0.05-0.0001), but not of primary hematopoietic stem cells and differentiated immune cells, FLT3 wild-type cells, retinal cells, and c-KIT-dependent cells. In vivo activity of MA49 against FLT3-ITD-positive leukemia cells is verified in a Danio rerio model. The degrader-induced loss of FLT3-ITD involves the pro-apoptotic BH3-only protein BIM and a previously unidentified degrader-induced depletion of protein-folding chaperones. The expression levels of HSP90 and HSP110 correlate with reduced AML patient survival (p < 0.1) and HSP90, HSP110, and BIM are linked to the expression of FLT3 in primary AML cells (p < 0.01). HSP90 suppresses degrader-induced FLT3-ITD elimination and thereby establishes a mechanistically defined feed-back circuit.