Antagonism of SET using OP449 enhances the efficacy of tyrosine kinase inhibitors and overcomes drug resistance in myeloid leukemia.
Antagonism of SET using OP449 enhances the efficacy of tyrosine kinase inhibitors and overcomes drug resistance in myeloid leukemia.
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DOI：
10.1158/1078-0432.ccr-13-2575
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发表时间：
2014-04-15
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影响因子：
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通讯作者：
Druker BJ
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文献类型：
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作者：
Agarwal A;MacKenzie RJ;Pippa R;Eide CA;Oddo J;Tyner JW;Sears R;Vitek MP;Odero MD;Christensen DJ;Druker BJ
SET 癌蛋白是蛋白磷酸酶 2A (PP2A) 的有效抑制剂，在白血病中过度表达。我们使用 OP449（一种特异性的细胞穿透肽，拮抗 SET 对 PP2A 的抑制作用）评估了 SET 拮抗作用在慢性粒细胞白血病 (CML) 和急性粒细胞白血病 (AML) 细胞系、小鼠白血病模型和主要患者样本中的功效。使用增殖、凋亡和结肠形成测定法测量 OP449 在 CML 和 AML 细胞系和原代样品中的体外细胞毒性和特异性。通过免疫印迹和 PP2A 测定评估 OP449 的靶标抑制功效。在人 HL-60 异种移植小鼠模型中测量了 OP449 的体内抗肿瘤功效。我们观察到 OP449 抑制 CML 细胞的生长，包括来自急变期疾病患者和携带高度耐药 BCR-ABL1 突变的患者的细胞。 OP449 和 ABL1 酪氨酸激酶抑制剂联合治疗对 K562 细胞和原代 CD34+ CML 细胞的细胞毒性显着增强。 OP449 处理后 SET 蛋白水平保持不变，但 BCR-ABL1 介导的下游信号传导因 BCR-ABL1、STAT5 和 AKT 等关键信号分子的降解而受到显着抑制。同样，单独使用 OP449 或与相应激酶抑制剂联合治疗后，AML 细胞系和具有各种遗传病变的原发性患者样本显示细胞生长受到抑制。最后，OP449 降低了人类白血病细胞异种移植小鼠的肿瘤负荷。我们展示了一种新的 SET 拮抗治疗范例，使用 OP449 与酪氨酸激酶抑制剂联合治疗 CML 和 AML。
The SET oncoprotein, a potent inhibitor of the protein phosphatase 2A (PP2A), is overexpressed in leukemia. We evaluated the efficacy of SET antagonism in chronic myeloid leukemia (CML) and acute myeloid leukemia (AML) cell lines, a murine leukemia model, and primary patient samples using OP449, a specific, cell-penetrating peptide that antagonizes SET's inhibition of PP2A. In vitro cytotoxicity and specificity of OP449 in CML and AML cell lines and primary samples were measured using proliferation, apoptosis and colonogenic assays. Efficacy of target inhibition by OP449 is evaluated by immunoblotting and PP2A assay. In vivo antitumor efficacy of OP449 was measured in human HL-60 xenografted murine model. We observed that OP449 inhibited growth of CML cells including those from patients with blastic phase disease and patients harboring highly drug-resistant BCR-ABL1 mutations. Combined treatment with OP449 and ABL1 tyrosine kinase inhibitors was significantly more cytotoxic to K562 cells and primary CD34+ CML cells. SET protein levels remained unchanged with OP449 treatment, but BCR-ABL1-mediated downstream signaling was significantly inhibited with the degradation of key signaling molecules such as BCR-ABL1, STAT5, and AKT. Similarly, AML cell lines and primary patient samples with various genetic lesions showed inhibition of cell growth after treatment with OP449 alone or in combination with respective kinase inhibitors. Finally, OP449 reduced the tumor burden of mice xenografted with human leukemia cells. We demonstrate a novel therapeutic paradigm of SET antagonism using OP449 in combination with tyrosine kinase inhibitors for the treatment of CML and AML.