Phenothiazines induce PP2A-mediated apoptosis in T cell acute lymphoblastic leukemia
Phenothiazines induce PP2A-mediated apoptosis in T cell acute lymphoblastic leukemia
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DOI：
10.1172/jci65093
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发表时间：
2014-02-01
影响因子：
15.9
通讯作者：
Aster, Jon C.
中科院分区：
文献类型：
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作者：
Gutierrez, Alejandro;Pan, Li;Aster, Jon C.
T细胞急性淋巴细胞白血病（T-ALL）是一种侵袭性癌症，通常与NOTCH 1的激活突变和MYC的失调有关。在这里，我们进行了2次互补筛选，以鉴定FDA批准的药物和具有抗T-ALL活性的药物样小分子。我们开发了一种斑马鱼系统来筛选小分子对MYC过表达胸腺细胞的毒性活性，并使用人类T-ALL细胞系筛选与Notch抑制剂协同作用的小分子。我们在两个筛选中鉴定了抗精神病药物奋乃静，因为其能够诱导鱼类、小鼠和人类T-ALL细胞的凋亡。使用配体亲和色谱结合质谱，我们确定了蛋白磷酸酶2A（PP 2A）作为奋乃静的目标。用奋乃静处理的T-ALL细胞系表现出多种PP 2A底物的快速去磷酸化和随后的凋亡。此外，特异性PP 2A亚基的shRNA敲低减弱了奋乃静的活性，表明PP 2A介导了药物的抗白血病活性。最后，用奋乃静处理的人T-ALL在体外和体内表现出抑制的细胞生长和PP 2A靶点的去磷酸化。我们的研究结果提供了一个机械的解释反复识别吩噻嗪类药物具有抗癌作用。此外，这些数据表明，在T-ALL和其他癌症中由过度磷酸化的PP 2A底物驱动的药理学PP 2A活化具有治疗潜力。
T cell acute lymphoblastic leukemia (T-ALL) is an aggressive cancer that is frequently associated with activating mutations in NOTCH1 and dysregulation of MYC. Here, we performed 2 complementary screens to identify FDA-approved drugs and drug-like small molecules with activity against T-ALL. We developed a zebrafish system to screen small molecules for toxic activity toward MYC-overexpressing thymocytes and used a human T-ALL cell line to screen for small molecules that synergize with Notch inhibitors. We identified the antipsychotic drug perphenazine in both screens due to its ability to induce apoptosis in fish, mouse, and human T-ALL cells. Using ligand-affinity chromatography coupled with mass spectrometry, we identified protein phosphatase 2A (PP2A) as a perphenazine target. T-ALL cell lines treated with perphenazine exhibited rapid dephosphorylation of multiple PP2A substrates and subsequent apoptosis. Moreover, shRNA knockdown of specific PP2A subunits attenuated perphenazine activity, indicating that PP2A mediates the drug's antileukemic activity. Finally, human T-ALLs treated with perphenazine exhibited suppressed cell growth and dephosphorylation of PP2A targets in vitro and in vivo. Our findings provide a mechanistic explanation for the recurring identification of phenothiazines as a class of drugs with anticancer effects. Furthermore, these data suggest that pharmacologic PP2A activation in T-ALL and other cancers driven by hyperphosphorylated PP2A substrates has therapeutic potential.