Inhibition of mammalian target of rapamycin signaling by 2-(Morpholin-1-yl) pyrimido[2,1-α]isoquinolin-4-one
Inhibition of mammalian target of rapamycin signaling by 2-(Morpholin-1-yl) pyrimido[2,1-α]isoquinolin-4-one
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DOI：
10.1074/jbc.m704741200
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发表时间：
2007-08-17
影响因子：
4.8
通讯作者：
Lin, Richard Z.
中科院分区：
文献类型：
--
作者：
Ballou, Lisa M.;Selinger, Elzbieta S.;Lin, Richard Z.
通过哺乳动物雷帕霉素靶蛋白（mTOR）的信号传导在许多人类肿瘤中被过度激活，包括与结节性硬化症（TSC）相关的错构瘤。几种小分子如LY 294002抑制mTOR激酶活性，但它们也在相似浓度下抑制磷脂酰肌醇3-激酶（PI 3 K）。化合物401是DNA依赖性蛋白激酶（DNA-PK）的合成抑制剂，其也在体外靶向mTOR而非PI 3 K（Griffin，R. J.，丰塔纳，G.，戈尔丁，B。T.，Guiard，S.，哈德卡斯尔岛R.，Leahy，J. J.，马丁，N.，理查森，C.，Rigoreau湖，Stockley，M.，和史密斯，G。C.（2005）J. Med. Chem. 48，569-585）。我们使用401来测试mTOR抑制的细胞效应，而没有对PI 3 K的复杂副作用。用401处理细胞阻断了由mTOR-Raptor和mTOR-Rictor复合物修饰的位点的磷酸化（分别为核糖体蛋白S6激酶1 Thr（389）和Akt Ser（473））。相比之下，没有直接抑制Akt Thr（308）磷酸化，这是依赖于PI 3 K。在缺乏DNA-PK的细胞中也观察到类似的效果。401对TSC 1（-/-）成纤维细胞的增殖有抑制作用，但对TSC 1（-/-）细胞有抵抗作用。与雷帕霉素相反，用401长期处理TSC 1（-/-）细胞并没有上调磷酸化Akt Ser（473）。由于Akt活性增加促进存活，这可以解释为什么在401而不是雷帕霉素存在下细胞凋亡水平增加。这些结果表明，mTOR激酶抑制剂可能比雷帕霉素更有效地控制TSC错构瘤和其他依赖于mTOR活性升高的肿瘤的生长。
Signaling through the mammalian target of rapamycin (mTOR) is hyperactivated in many human tumors, including hamartomas associated with tuberous sclerosis complex (TSC). Several small molecules such as LY294002 inhibit mTOR kinase activity, but they also inhibit phosphatidylinositol 3-kinase (PI3K) at similar concentrations. Compound 401 is a synthetic inhibitor of DNA-dependent protein kinase (DNA-PK) that also targets mTOR but not PI3K in vitro (Griffin, R. J., Fontana, G., Golding, B. T., Guiard, S., Hardcastle, I. R., Leahy, J. J., Martin, N., Richardson, C., Rigoreau, L., Stockley, M., and Smith, G. C. (2005) J. Med. Chem. 48, 569-585). We used 401 to test the cellular effect of mTOR inhibition without the complicating side effects on PI3K. Treatment of cells with 401 blocked the phosphorylation of sites modified by mTOR-Raptor and mTOR-Rictor complexes (ribosomal protein S6 kinase 1 Thr(389) and Akt Ser(473), respectively). By contrast, there was no direct inhibition of Akt Thr(308) phosphorylation, which is dependent on PI3K. Similar effects were also observed in cells that lack DNA-PK. The proliferation of TSC1(-/-) fibroblasts was inhibited in the presence of 401, but TSC1(-/-) cells were resistant. In contrast to rapamycin, long-term treatment of TSC1(-/-) cells with 401 did not up-regulate phospho-Akt Ser(473). Because increased Akt activity promotes survival, this may explain why the level of apoptosis was increased in the presence of 401 but not rapamycin. These results suggest that mTOR kinase inhibitors might be more effective than rapamycins in controlling the growth of TSC hamartomas and other tumors that depend on elevated mTOR activity.