Differential effects of the Akt inhibitor MK-2206 on migration and radiation sensitivity of glioblastoma cells
Differential effects of the Akt inhibitor MK-2206 on migration and radiation sensitivity of glioblastoma cells
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DOI：
10.1186/s12885-019-5517-4
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发表时间：
2019-04-03
期刊：
影响因子：
3.8
通讯作者：
Sukhorukov, Vladimir L.
中科院分区：
文献类型：
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作者：
Djuzenova, Cholpon S.;Fiedler, Vanessa;Sukhorukov, Vladimir L.
研究背景大多数肿瘤细胞存在Akt的异常激活，Akt的异常激活可导致肿瘤细胞存活率的增加和对肿瘤放疗的抵抗。因此，靶向Akt可能是放射增敏的有前途的策略。在这里，我们探索Akt抑制剂MK-2206单独和与双重PI 3 K和mTOR抑制剂PI-103组合对胶质母细胞瘤细胞辐射敏感性的影响。方法采用单细胞追踪和创伤愈合迁移试验、集落形成试验、Western印迹、流式细胞术和电旋转等方法，检测MK-2206和PI-103和/或辐射对细胞迁移、辐射敏感性、几种标志蛋白表达、DNA损伤、两例胶质母细胞瘤的细胞周期进程和质膜性质（DK-MG和SNB 19）细胞系，以前显示出明显不同的迁移行为和响应PI 3 K/mTOR抑制。2206强烈降低DK-MG的迁移，但仅适度降低SNB 19细胞的迁移。令人惊讶的是，MK-2206并没有引起放射增敏，但甚至增加了照射后的集落形成能力。此外，MK-2206没有增强PI-103的放射增敏作用。结果似乎与MK-2206处理细胞中p-Akt的强烈耗竭相矛盾。MK-2206处理的细胞的辐射抗性的可能原因可能未改变，或者在SNB 19细胞的情况下，与PI-103处理的样品中这些蛋白质的表达降低相比，甚至增加了p-mTOR和p-S6的水平。MK-2206不增强IR诱导的DNA损伤，不引起细胞周期畸变，也不引起细胞凋亡或过度自噬。结论MK-2206能有效抑制两种胶质母细胞瘤细胞株Akt的表达。然而，由于mTOR响应于PTEN突变细胞中Akt抑制的异常激活，需要仔细定义治疗窗口，或者应考虑Akt和mTOR抑制剂的组合。
BackgroundMost tumor cells show aberrantly activated Akt which leads to increased cell survival and resistance to cancer radiotherapy. Therefore, targeting Akt can be a promising strategy for radiosensitization. Here, we explore the impact of the Akt inhibitor MK-2206 alone and in combination with the dual PI3K and mTOR inhibitor PI-103 on the radiation sensitivity of glioblastoma cells. In addition, we examine migration of drug-treated cells.MethodsUsing single-cell tracking and wound healing migration tests, colony-forming assay, Western blotting, flow cytometry and electrorotation we examined the effects of MK-2206 and PI-103 and/or irradiation on the migration, radiation sensitivity, expression of several marker proteins, DNA damage, cell cycle progression and the plasma membrane properties in two glioblastoma (DK-MG and SNB19) cell lines, previously shown to differ markedly in their migratory behavior and response to PI3K/mTOR inhibition.ResultsWe found that MK-2206 strongly reduces the migration of DK-MG but only moderately reduces the migration of SNB19 cells. Surprisingly, MK-2206 did not cause radiosensitization, but even increased colony-forming ability after irradiation. Moreover, MK-2206 did not enhance the radiosensitizing effect of PI-103. The results appear to contradict the strong depletion of p-Akt in MK-2206-treated cells. Possible reasons for the radioresistance of MK-2206-treated cells could be unaltered or in case of SNB19 cells even increased levels of p-mTOR and p-S6, as compared to the reduced expression of these proteins in PI-103-treated samples. We also found that MK-2206 did not enhance IR-induced DNA damage, neither did it cause cell cycle distortion, nor apoptosis nor excessive autophagy.ConclusionsOur study provides proof that MK-2206 can effectively inhibit the expression of Akt in two glioblastoma cell lines. However, due to an aberrant activation of mTOR in response to Akt inhibition in PTEN mutated cells, the therapeutic window needs to be carefully defined, or a combination of Akt and mTOR inhibitors should be considered.