Inhibition of Akt inhibits growth of glioblastoma and glioblastoma stem-like cells.
Inhibition of Akt inhibits growth of glioblastoma and glioblastoma stem-like cells.
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DOI：
10.1158/1535-7163.mct-08-0680
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发表时间：
2009-02
影响因子：
5.7
通讯作者：
Riggins GJ
中科院分区：
文献类型：
--
作者：
Gallia GL;Tyler BM;Hann CL;Siu IM;Giranda VL;Vescovi AL;Brem H;Riggins GJ
Akt 通路是许多人类恶性肿瘤（包括多形性胶质母细胞瘤 (GBM)）中常见激活的信号级联反应。该通路可以通过许多上游改变来激活，包括 EGFR 的基因组扩增、PTEN 缺失或 PIK3CA 突变。在这项研究中，我们在同基因细胞培养系统中筛选了 PI3K/Akt 小分子抑制剂，该系统具有继发于 PIK3CA 突变的激活的 Akt 通路。一种小分子 A-443654 对具有突变表型的细胞表现出最大的选择性抑制作用。基于这些发现，该抑制剂针对一组 GBM 细胞系进行了体外筛选。所有测试的细胞系均对 A-443654 敏感，平均 IC50 约为 150 nM。 A-443654 的类似物在阻断 Akt 结合的区域被甲基化，活性平均降低了 36 倍。 Caspase 测定和双流式细胞术分析证明了细胞死亡的凋亡机制。 A-443654 在大鼠 GBM 颅内模型中进行了进一步测试。与对照动物相比，用含有 A-443654 的聚合物进行颅内治疗的动物的存活率显着延长；当同时或以延迟方式植入含有 A-443654 的聚合物时，动物的存活时间分别比对照组长 79% 和 43%。与传统培养的 GBM 细胞系相比，这种小分子还可以抑制 GBM 干细胞样细胞，具有相似的功效。这些结果表明，局部递送 Akt 小分子抑制剂可有效对抗实验性颅内神经胶质瘤，且未观察到对干细胞条件下生长的 GBM 细胞的耐药性。
A commonly activated signaling cascade in many human malignancies including glioblastoma multiforme (GBM) is the Akt pathway. This pathway can be activated via numerous upstream alterations including genomic amplification of EGFR, PTEN deletion, or PIK3CA mutations. In this study, we screened PI3K/Akt small molecule inhibitors in an isogenic cell culture system with an activated Akt pathway secondary to a PIK3CA mutation. One small molecule, A-443654, demonstrated the greatest selective inhibition of cells with the mutant phenotype. Based on these findings, this inhibitor was screened in vitro against a panel of GBM cell lines. All cell lines tested were sensitive to A-443654 with a mean IC50 of approximately 150 nM. An analogue of A-443654, methylated at a region that blocks Akt binding, decreased activity by an average of 36 fold. Caspase assays and dual flow cytometric analysis demonstrated an apoptotic mechanism of cell death. A-443654 was further tested in a rat intracranial model of GBM. Animals treated intracranially with polymers containing A-443654 had significantly extended survival compared to control animals; animals survived 79% and 43% longer than controls when A-443654-containing polymers were implanted simultaneously or in a delayed fashion, respectively. This small molecule also inhibited GBM stem-like cells with similar efficacy compared to traditionally cultured GBM cell lines. These results suggest that local delivery of an Akt small molecule inhibitor is effective against experimental intracranial glioma, with no observed resistance to GBM cells grown in stem cell conditions.