Neuroendocrinology. 2018;106(4):335-351. doi: 10.1159/000481887. Epub 2017 Oct 2.
Glycogen synthase kinase 3α/β (GSK3α/β) is a serine/threonine kinase that plays a critical role in cancer.
In this study, we evaluated the effects of the specific GSK3α/β inhibitor AR-A014418 in vitro to gain novel insights into GSK3α/β signaling in neuroendocrine tumors (NETs).
Human NET cell lines (BON1, QGP1, H727, and GOT1) were treated with different concentrations of AR-A014418 alone and in combination with lovastatin, everolimus, 5-fluorouracil (5-FU), and γ-irradiation.
AR-A014418 significantly dose- and time-dependently decreased cell viability in all 4 NET cell lines through inhibition of epithelial growth factor receptor and mTORC1/p70S6K signaling, as well as cyclin D3 downregulation and induction of pChk1. In all cell lines tested, FACS analysis showed an AR-A014418-induced increase in the sub-G1 phase, reflecting cell death. Apoptosis induction was observed in H727, GOT1 and QGP1 cells, but not in BON1 cells. Furthermore, significant antimigratory effects upon GSK3α/β inhibition were found and were associated with β-catenin downregulation in all cell lines tested. Compensatory upregulation of pAkt and pERK in response to GSK3α/β inhibition was prevented by combining AR-A014418 with the ERK and Akt inhibitor lovastatin. Accordingly, the lovastatin/AR-A014418 combination was synergistic in BON1 and QGP1 cells. Moreover, AR-A014418 displayed promising chemosensitizing effects on 5-FU in QGP1 and slight radiosensitizing properties in BON1 and QGP1 cells.
Our data provide new insights into the role of GSK3α/β in NETs and suggest that GSK3α/β inhibition could be a novel therapeutic option in NETs, especially in combination with lovastatin or 5-FU, depending on tumor entity.
糖原合成酶激酶 3α/β（GSK3α/β）是一种丝氨酸/苏氨酸激酶，在癌症中起着关键作用。
本研究评估了特异性 GSK3α/β 抑制剂 AR-A014418 在体外对神经内分泌肿瘤（NETs）中 GSK3α/β 信号的影响，以期获得新的见解。
人 NET 细胞系（BON1、QGP1、H727 和 GOT1）单独或与洛伐他汀、依维莫司、5-氟尿嘧啶（5-FU）和γ-辐射联合使用不同浓度的 AR-A014418 进行处理。
AR-A014418 通过抑制表皮生长因子受体和 mTORC1/p70S6K 信号通路以及下调细胞周期蛋白 D3和诱导 pChk1，显著地剂量和时间依赖性地降低了所有 4 种 NET 细胞系的细胞活力。在所有测试的细胞系中，FACS 分析显示 AR-A014418 诱导的亚 G1 期增加，反映细胞死亡。在 H727、GOT1 和 QGP1 细胞中观察到凋亡诱导，但在 BON1 细胞中未观察到。此外，在所有测试的细胞系中发现了 GSK3α/β 抑制后的明显抗迁移作用，与β-连环蛋白下调有关。通过将 AR-A014418 与 ERK 和 Akt 抑制剂洛伐他汀联合使用，可以防止 GSK3α/β 抑制后 pAkt 和 pERK 的代偿性上调。因此，洛伐他汀/AR-A014418 联合在 BON1 和 QGP1 细胞中具有协同作用。此外，AR-A014418 在 QGP1 中显示出对 5-FU 的有前途的化疗增敏作用，并且在 BON1 和 QGP1 细胞中具有轻微的放射增敏作用。
我们的数据提供了 GSK3α/β 在 NETs 中的作用的新见解，并表明 GSK3α/β 抑制可能是 NETs 的一种新的治疗选择，特别是与洛伐他汀或 5-FU 联合使用，具体取决于肿瘤实体。
