In Vitro Cytotoxicity and In Vivo Efficacy, Pharmacokinetics, and Metabolism of 10074-G5, a Novel Small-Molecule Inhibitor of c-Myc/Max Dimerization
In Vitro Cytotoxicity and In Vivo Efficacy, Pharmacokinetics, and Metabolism of 10074-G5, a Novel Small-Molecule Inhibitor of c-Myc/Max Dimerization
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DOI：
10.1124/jpet.110.170555
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发表时间：
2010-12-01
影响因子：
3.5
通讯作者：
Eiseman, Julie L.
中科院分区：
文献类型：
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作者：
Clausen, Dana M.;Guo, Jianxia;Eiseman, Julie L.
c-Myc 癌蛋白在许多肿瘤中过度表达，对于维持转化细胞的增殖至关重要。为了发挥转录因子的作用，c-Myc 必须通过每个蛋白质中的基本螺旋-环-螺旋亮氨酸拉链蛋白 (bHLH-ZIP) 结构域与 Max 形成二聚体。小分子 7-硝基-N-(2-苯基苯基)-2,1,3-苯并恶二唑-4-胺 (10074-G5) 结合并扭曲 c-Myc 的 bHLH-ZIP 结构域，从而抑制 c-Myc/Max 异二聚体形成并抑制其转录活性。我们报告了 10074-G5 在人类异种移植小鼠中的体外细胞毒性和体内功效、药效学、药代动力学和代谢。在体外，10074-G5 抑制 Daudi Burkitt 淋巴瘤细胞的生长并破坏 c-Myc/Max 二聚化。 10074-G5 对连续 5 天静脉注射 20 mg/kg 10074-G5 的 C.B-17 SCID 小鼠 Daudi 异种移植物的生长没有影响。治疗后 2 或 24 小时未观察到 Daudi 异种移植物中 c-Myc/Max 二聚化的抑制。采用高效液相色谱-紫外法测定不同基质中10074-G5的浓度，并采用液相色谱/串联质谱法鉴定10074-G5的代谢物。 10074-G5 在接受 20 mg/kg 静脉注射治疗的小鼠中的血浆半衰期37分钟，血浆峰值浓度为58μM，比肿瘤峰值浓度高10倍。抗肿瘤活性的缺乏可能是由于10074-G5快速代谢为无活性代谢物造成的，导致10074-G5的肿瘤浓度不足以抑制c-Myc/Max二聚化。我们在小鼠体内鉴定出 10074-G5 代谢物将有助于设计新的、代谢更稳定的 c-Myc 小分子抑制剂。
The c-Myc oncoprotein is overexpressed in many tumors and is essential for maintaining the proliferation of transformed cells. To function as a transcription factor, c-Myc must dimerize with Max via the basic helix-loop-helix leucine zipper protein (bHLH-ZIP) domains in each protein. The small molecule 7-nitro-N-(2-phenylphenyl)-2,1,3-benzoxadiazol-4-amine (10074-G5) binds to and distorts the bHLH-ZIP domain of c-Myc, thereby inhibiting c-Myc/Max heterodimer formation and inhibiting its transcriptional activity. We report in vitro cytotoxicity and in vivo efficacy, pharmacodynamics, pharmacokinetics, and metabolism of 10074-G5 in human xenograft-bearing mice. In vitro, 10074-G5 inhibited the growth of Daudi Burkitt's lymphoma cells and disrupted c-Myc/Max dimerization. 10074-G5 had no effect on the growth of Daudi xenografts in C.B-17 SCID mice that were treated with 20 mg/kg 10074-G5 intravenously for 5 consecutive days. Inhibition of c-Myc/Max dimerization in Daudi xenografts was not seen 2 or 24 h after treatment. Concentrations of 10074-G5 in various matrices were determined by high-performance liquid chromatography-UV, and metabolites of 10074-G5 were identified by liquid chromatography/tandem mass spectrometry. The plasma half-life of 10074-G5 in mice treated with 20 mg/kg i.v. was 37 min, and peak plasma concentration was 58 mu M, which was 10-fold higher than peak tumor concentration. The lack of antitumor activity probably was caused by the rapid metabolism of 10074-G5 to inactive metabolites, resulting in tumor concentrations of 10074-G5 insufficient to inhibit c-Myc/Max dimerization. Our identification of 10074-G5 metabolites in mice will help design new, more metabolically stable small-molecule inhibitors of c-Myc.