Cell & Molecular Biology Section, Pediatric Oncology Branch, Center for Cancer Research, National Cancer Institute, NIH, Bethesda, Maryland 20892, USA.
Clin Cancer Res. 2012 Jul 1;18(13):3603-15. doi: 10.1158/1078-0432.CCR-11-3321. Epub 2012 May 1.
Activation of Akt is a marker of decreased event-free or overall survival in neuroblastoma patients. MK-2206, a novel allosteric Akt inhibitor, is now tested in clinical trials in adult cancers. In this study, effect of MK-2206 on tumor growth and murine survival, alone or in combination, with etoposide or rapamycin was evaluated.
The anticell proliferation effect of MK-2206 was tested in eight neuroblastoma cell lines by MTS assay. Caspase-3/7 activity, cell-cycle analysis, and reactive oxygen species (ROS) production were determined. Effect of MK-2206 combined with etoposide or rapamycin was evaluated in vitro and in vivo. Akt phosphorylation was measured by Western blotting in neuroblastoma cells and tumors.
In vitro, MK-2206 treatment inhibited neuroblastoma cell proliferation, which was accompanied by a cell line selective G(1) arrest of cell cycle or production of ROS. A synergistic effect between MK-2206 and etoposide was detected in four tested neuroblastoma cell lines via caspase-dependent apoptosis, whereas increased inhibition of cell growth induced by combination of MK-2206 and rapamycin was mediated by ROS production. In vivo, MK-2206 alone decreased tumor growth and increased murine survival at dose that inhibited Akt phosphorylation in tumors. MK-2206, in combination with etoposide or rapamycin, caused a significant decrease in tumor growth and increase of murine survival compared with MK-2206 alone.
Akt inhibition by MK-2206 increased the efficacy of etoposide or rapamycin. Our study supports future clinical evaluation of MK-2206 in combination with conventional cytotoxic therapy or with rapamycin in high-risk neuroblastoma patients.
在神经母细胞瘤患者中，Akt 的激活是无事件生存或总生存降低的标志物。MK-2206 是一种新型的变构 Akt 抑制剂，目前正在成人癌症的临床试验中进行测试。在这项研究中，评估了 MK-2206 单独或与依托泊苷或雷帕霉素联合使用对肿瘤生长和小鼠存活的影响。
通过 MTS 测定法在八种神经母细胞瘤细胞系中测试 MK-2206 的抗细胞增殖作用。测定了 caspase-3/7 活性、细胞周期分析和活性氧 (ROS) 的产生。评估了 MK-2206 与依托泊苷或雷帕霉素联合使用的体外和体内效果。通过 Western blot 测定神经母细胞瘤细胞和肿瘤中的 Akt 磷酸化。
体外，MK-2206 处理抑制神经母细胞瘤细胞增殖，这伴随着细胞周期的细胞系选择性 G1 期阻滞或 ROS 的产生。在四种测试的神经母细胞瘤细胞系中，通过 caspase 依赖性凋亡检测到 MK-2206 与依托泊苷之间存在协同作用，而 MK-2206 与雷帕霉素联合使用引起的细胞生长抑制增加是通过 ROS 产生介导的。在体内，MK-2206 单独使用时可降低肿瘤生长并增加荷瘤小鼠的存活，而该剂量可抑制肿瘤中的 Akt 磷酸化。与 MK-2206 单独使用相比，MK-2206 与依托泊苷或雷帕霉素联合使用可显著降低肿瘤生长并增加小鼠存活。
MK-2206 抑制 Akt 增加了依托泊苷或雷帕霉素的疗效。我们的研究支持未来在高危神经母细胞瘤患者中对 MK-2206 联合常规细胞毒性疗法或与雷帕霉素进行临床评估。
