作者: Maertens, Johan ; Gielen, Olga ; Vandersmissen, Charlien ; Cools, Jan ; Jacobs, Kris ; Provost, Sarah ; Govaerts, Inge ; Segers, Heidi ; Nittner, David ; Prieto, Cristina ; De Keersmaecker, Kim ; Boeckx, Nancy

Abstract:

Background:

T cell acute lymphoblastic leukemia (T-ALL) is a high-risk subtype that comprises 10–15% of childhood and 20–25% of adult ALL cases. Over 70% of T-ALL patients harbor activating mutations in the NOTCH1 signaling pathway and are predicted to be sensitive to gamma-secretase inhibitors. We have recently demonstrated that selective inhibition of PSEN1-containing gamma-secretase complexes can overcome the dose-limiting toxicity associated with broad gamma-secretase inhibitors. In this study, we developed combination treatment strategies with the PSEN1-selective gamma-secretase inhibitor MRK-560 and other targeted agents (kinase inhibitors ruxolitinib and imatinib; XPO-1 inhibitor KPT-8602/eltanexor) for the treatment of T-ALL.

Methods:

We treated T-ALL cell lines in vitro and T-ALL patient-derived xenograft (PDX) models in vivo with MRK-560 alone or in combination with other targeted inhibitors (ruxolitinib, imatinib or KPT-8602/eltanexor). We determined effects on proliferation of the cell lines and leukemia development and survival in the PDX models.

Results:

All NOTCH1-signaling-dependent T-ALL cell lines were sensitive to MRK-560 and its combination with ruxolitinib or imatinib in JAK1- or ABL1-dependent cell lines synergistically inhibited leukemia proliferation. We also observed strong synergy between MRK-560 and KPT-8602 (eltanexor) in all NOTCH1-dependent T-ALL cell lines. Such synergy was also observed in vivo in a variety of T-ALL PDX models with NOTCH1 or FBXW7 mutations. Combination treatment significantly reduced leukemic infiltration in vivo and resulted in a survival benefit when compared to single treatment groups.We did not observe weight loss or goblet cell hyperplasia in single drug or combination treated mice when compared to control.

Conclusions:

These data demonstrate that the antileukemic effect of PSEN1-selective gamma-secretase inhibition can be synergistically enhanced by the addition of other targeted inhibitors. The combination of MRK-560 with KPT-8602 is a highly effective treatment combination, which circumvents the need for the identification of additional mutations and provides a clear survival benefit in vivo. These promising preclinical data warrant further development of combination treatment strategies for T-ALL based on PSEN1-selective gamma-secretase inhibition.

2015-11-25·Journal of medicinal chemistry1区 · 医学

Discovery of a Novel, Potent Spirocyclic Series of γ-Secretase Inhibitors

1区 · 医学

Article

作者: Josien, Hubert B. ; Li, Hongmei ; Xu, Ruo ; Clader, John W. ; Lee, Julie ; Wu, Wen-Lian ; Pissarnitski, Dmitri A. ; Terracina, Giuseppe ; Hyde, Lynn ; Burnett, Duane A. ; Song, Lixin ; Parker, Eric M. ; Zhang, Lili ; Zhao, Zhiqiang

In the present paper, we described the design, synthesis, SAR, and biological profile of a novel spirocyclic sulfone series of γ-secretase inhibitors (GSIs) related to MRK-560. We utilized an additional spirocyclic ring system to stabilize the active chair conformation of the parent γ-secretase inhibitors. The resulting series is devoid of the CYP2C9 inhibition liability of MRK-560. A few representative analogs were assessed in a nontransgenic animal model of Alzheimer's disease (AD), demonstrating reduction of amyloid-β (Aβ) in the CNS after acute oral dosing. A spirocyclic phosphonate was identified as the optimal ring system for both potency and pharmacokinetics. Compared to GSIs studied in the clinic, representative spirocyclic phosphonate 18a(-) features improved selectivity for the inhibition of the PS-1 isoform of γ-secretase (33-fold vs PS-2), which may alleviate the adverse effect profile of the clinical GSIs.

2015-08-03·The International journal of neuroscience4区 · 医学

Quantitative assessment of Aβ peptide in brain, cerebrospinal fluid and plasma following oral administration of γ-secretase inhibitor MRK-560 in rats

4区 · 医学

Article

作者: James C Hershey ; Guoxin Wu ; Zhenhua Wu ; Sang Na

The β-amyloid peptides (Aβ) are thought to play a critical role in the pathophysiology of Alzheimer's disease. One therapeutic strategy aimed to reduce or eliminate the production of Aβ peptides is inhibition of the γ-secretase enzyme, which cleaves amyloid precursor protein to form Aβ peptides. We studied the in vivo effects of the potent, orally bioavailable and brain penetrant γ-secretase inhibitor (GSI), MRK-560, on both Aβx-40 and Aβx-42 in multiple compartments (plasma, the brain and cerebrospinal fluid) of rat. Although there were differences in the time course and magnitude of the changes, the results showed that MRK-560 caused marked inhibition of both Aβx-40 and Aβx-42 in all three compartments. We identified good correlations between plasma Aβx-40 versus brain Aβx-40 (r = 0.84), and plasma Aβx-40 versus CSF Aβx-40 (r = 0.85), indicating that these pools of Aβ are related dynamically. These results suggest that central Aβ changes that occur following acute dosing with MRK-560 can be predicted based on plasma Aβ changes and could thus serve as a useful biomarker to help accelerate decision-making during early clinical development.

项与 MRK-560 相关的新闻（医药）

2022-10-25

·生物制品圈

施一公团队再突破！新研究或有助于开发靶向γ-分泌酶药物

导读：抑制γ分泌酶活性是阿尔茨海默病（AD）的潜在治疗策略。MRK-560是一种选择性抑制剂，对PS1的效力高于PS2，PS2是γ分泌酶催化亚基的两种亚型，尽管如此，其潜在机制仍然难以捉摸。2022年10月22日，西湖大学施一公及清华大学周瑞共同通讯在线发布了研究论文。该研究报道了含有和不含MRK-560的PS1和PS2的γ-分泌酶复合物的冷冻电子显微镜结构，总体分辨率为2.9-3.4 Å。MRK-560占据PS1的底物结合位点，但在PS2中不可见。结构比较发现，PS1中的Thr281和Leu282是MRK-560亚型依赖性敏感性的决定因素，PS1和PS2之间的交换实验证实了这一点。通过揭示早老素的亚型选择性抑制机制，该研究工作可能有助于未来靶向γ-分泌酶的药物的发现。https://www-nature-com.libproxy1.nus.edu.sg/articles/s41467-022-33817-5抑制γ-分泌酶活性策略显示严重副作用 01 γ-分泌酶复合物可切割多种I型跨膜蛋白，以淀粉样前体蛋白(APP)和Notch蛋白为例。APP最初被β-分泌酶切割产生羧基端99残基片段，称为APP- C99，然后被γ-分泌酶连续切割，释放出不同长度的APP胞内结构域(AICD)和β-淀粉样肽(Aβ)。相对较长的Aβ容易在大脑中形成低聚物和淀粉样斑块。淀粉样斑块的积累是AD的一个标志。抑制γ-分泌酶活性已被用于AD的治疗。然而，到目前为止，这一策略尚未显示出益处；更糟糕的是，在临床试验中观察到严重的副作用。副作用可能部分归因于非特异性抑制γ-分泌酶对其他底物的切割，特别是Notch，它在发育和细胞命运的决定中起着至关重要的作用。在Notch上选择性抑制APP的γ-分泌酶切割被认为可以减轻副作用。然而，APP和Notch以类似的方式结合γ-分泌酶，使底物选择性γ-分泌酶抑制剂(GSIs)的设计复杂化。MRK-560与PS1之间存在优先关联 02MRK-560 是一种用于 PS1 和 PS2 的同种型选择性抑制剂，为了验证MRK-560的抑制作用，研究团队使用纯化的PS1或PS2复合物重建了体外裂解测定。Aβ40（不同长度的 Aβs 中的主要裂解产物）和 AICD（其裂解反映了γ分泌酶的内肽酶活性）的产生分别用 AlphaLISA 和蛋白质印迹进行测量。与先前的研究一致，MRK-560显示出对PS1复合物的更有效抑制。集成电路PS1或PS2复合物的MRK-560估计分别为33±2 nM或173±24 nM。在200 nM MRK-560存在下，PS1复合物产生的AICD被完全抑制。相比之下，即使在存在10μM MRK-560的情况下，PS2复合物产生的AICD仍然可以检测到。在MRK-560结合时，与无配体状态相比，PS1经历了实质性的构象变化。与其他报告的 GSI 类似MRK-560结合诱导两条β的形成和PAL环的运动。TM6之后的胞质序列折叠到TM6a，TM6a通过柔性连接子连接到TM6并向抑制剂结合位点弯曲。PS2M采用与apo复合物几乎相同的构象，缺乏抗平行β片和TM6a的延伸特征。平行结构分析表明，与PS2相比，MRK-560与PS1之间存在优先关联。接下来，研究人员检查了结构以确定MRK-560同种型选择性的分子基础。MRK-560与PS1的Asp385，Leu432和Leu282形成三个氢键（H键）。其中，Asp385是PS1的催化残基之一，Leu432先于PAL基序，Leu282位于PS1的TM6a和β1之间的中间回路。MRK-560的二氟苄基（DFB）和三氟甲磺酰胺（TFMS）基团与Val272，Thr281，Lys380，Gly382，Ala431和Pro433相互作用，氯苯基（CP）基团与Val379，Leu381，Leu418，Thr421，Leu422和Ala434的侧链相互作用。为了研究这两个残基是否负责对MRK-560的亚型依赖性敏感性，研究人员生成了PS1和PS2变体，在这两个位置交换了残基，并检查了它们对MRK-560抑制的反应。共生成了六个变体，包括PS1中的Thr281 / Leu282与PS2中的Pro287 / Ile288的单残差交换和双残留物交换。在体外裂解测定中检查MRK-560对六种含有PS1 / PS2突变体的复合物的反应，每种复合物纯化至均一性。研究意义 03 研究表明，MRK-560会减少大脑中Aβ的产生。重要的是，它不会在野生型小鼠模型中诱发Notch相关的副作用。在这项工作中，研究人员测定了MRK-560处理过的PS1/PS2复合物的冷冻电镜结构，以阐明MRK-560亚型特异性的分子基础。MRK-560占据PS1的底物结合位点，但在PS2中不可见。结构比较发现，PS1中的Thr281和Leu282是MRK-560亚型依赖性敏感性的决定因素，PS1和PS2之间的交换实验证实了这一点。通过揭示早老素的亚型选择性抑制机制，该研究工作可能有助于未来靶向γ-分泌酶的药物的发现。参考资料：https://www-nature-com.libproxy1.nus.edu.sg/articles/s41467-022-33817-5

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