GZD824 Inhibits GCN2 and Sensitizes Cancer Cells to Amino Acid Starvation Stress
GZD824 Inhibits GCN2 and Sensitizes Cancer Cells to Amino Acid Starvation Stress
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DOI：
10.1124/molpharm.120.000070
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发表时间：
2020-12-01
影响因子：
3.6
通讯作者：
Tomida, Akihiro
中科院分区：
文献类型：
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作者：
Kato, Yu;Kunimasa, Kazuhiro;Tomida, Akihiro
真核起始因子2 α (eIF2 α)激酶一般控制非去抑制2 （GCN2）通过激活诱导激活转录因子4 （ATF4）的综合应激反应，驱动细胞适应氨基酸限制。在这里，我们发现了一种多激酶抑制剂GZD824，我们使用基于细胞的ATF4免疫染色试验确定了它，可以抑制癌细胞中的GCN2途径。事实上，GZD824在氨基酸饥饿胁迫下抑制GCN2激活、eIF2 α磷酸化和ATF4诱导。然而，在较低的非抑制性浓度下，GZD824在非应激条件下以依赖gcn2的方式刺激eIF2 α磷酸化和ATF4表达。可以想象，这种双重特性源于对GCN2的直接作用，在无细胞GCN2激酶试验中也观察到，并且选择性GCN2抑制剂也具有这种特性。与GCN2通路抑制一致，GZD824使某些癌细胞对氨基酸饥饿应激敏感，类似于ATF4敲除。这些结果确定了GZD824是一种多激酶GCN2抑制剂，并可能增强其作为正在开发的药物的效用。gzd824作为一种直接的一般控制非抑制2 （GCN2）抑制剂，在氨基酸限制时抑制综合应激反应的激活，而在较低的非抑制性浓度下却矛盾地刺激这种应激信号通路。我们在此确定的药理学活性将为使用GZD824阐明GCN2的调控机制以及评估GCN2激活转录因子4途径作为癌症治疗靶点的潜力提供基础。
Eukaryotic initiation factor 2 alpha (eIF2 alpha) kinase general control nonderepressible 2 (GCN2) drives cellular adaptation to amino acid limitation by activating the integrated stress response that induces activating transcription factor 4 (ATF4). Here, we found that a multikinase inhibitor, GZD824, which we identified using a cell-based assay with ATF4 immunostaining, inhibited the GCN2 pathway in cancer cells. Indeed, GZD824 suppressed GCN2 activation, eIF2 alpha phosphorylation, and ATF4 induction during amino acid starvation stress. However, at lower nonsuppressive concentrations, GZD824 paradoxically stimulated eIF2 alpha phosphorylation and ATF4 expression in a GCN2-dependent manner under unstressed conditions. Such dual properties conceivably arose from a direct effect on GCN2, as also observed in a cell-free GCN2 kinase assay and shared by a selective GCN2 inhibitor. Consistent with the GCN2 pathway inhibition, GZD824 sensitized certain cancer cells to amino acid starvation stress similarly to ATF4 knockdown. These results establish GZD824 as a multikinase GCN2 inhibitor and may enhance its utility as a drug under development.SIGNIFICANCE STATEMENTGZD824, as a direct general control nonderepressible 2 (GCN2) inhibitor, suppresses activation of the integrated stress response during amino acid limitation, whereas it paradoxically stimulates this stress-signaling pathway at lower nonsuppressive concentrations. The pharmacological activity we identify herein will provide the basis for the use of GZD824 to elucidate the regulatory mechanisms of GCN2 and to evaluate the potential of the GCN2-activating transcription factor 4 pathway as a target for cancer therapy.