Inhibition of Mutant GNAQ Signaling in Uveal Melanoma Induces AMPK-Dependent Autophagic Cell Death
Inhibition of Mutant GNAQ Signaling in Uveal Melanoma Induces AMPK-Dependent Autophagic Cell Death
复制标题
DOI：
10.1158/1535-7163.mct-12-1020
复制
发表时间：
2013-05-01
影响因子：
5.7
通讯作者：
Schwartz, Gary K.
中科院分区：
文献类型：
--
作者：
Ambrosini, Grazia;Musi, Elgilda;Schwartz, Gary K.
在80%的葡萄膜黑色素瘤中发现了GNAQ和GNA11基因的致癌突变。这些突变导致RAF/MEK信号通路的激活，最终导致ERK1/2丝裂原活化蛋白激酶的刺激。在这项研究中，使用siRNA策略，我们发现突变体GNAQ同时向MEK和AKT发出信号，并且MEK抑制剂selumetinib （AZD6244）和AKT抑制剂MK2206联合抑制这些途径诱导了细胞活力的协同降低。这种效应是基因型依赖性的，因为自噬标记物beclin1和LC3在gnaq突变细胞中被诱导，而凋亡是braf突变细胞的细胞死亡机制，没有突变的细胞发生细胞周期阻滞。抑制MEK/ATK通路可诱导gnaq突变细胞中amp活化蛋白激酶（AMPK）的激活。siRNA对AMPK的下调或化合物C对其的抑制并不能使细胞免于自噬，而是细胞凋亡，这表明AMPK是突变GNAQ信号的关键调节因子，是自噬和凋亡之间的开关。此外，这种联合治疗在抑制异种移植小鼠模型中的肿瘤生长方面是有效的。这些发现表明，抑制MEK和AKT可能是葡萄膜黑色素瘤患者靶向治疗的一种有希望的方法。(c) 2013年AACR。
Oncogenic mutations in GNAQ and GNA11 genes are found in 80% of uveal melanoma. These mutations result in the activation of the RAF/MEK signaling pathway culminating in the stimulation of ERK1/2 mitogen-activated protein kinases. In this study, using a siRNA strategy, we show that mutant GNAQ signals to both MEK and AKT, and that combined inhibition of these pathways with the MEK inhibitor selumetinib (AZD6244) and the AKT inhibitor MK2206 induced a synergistic decrease in cell viability. This effect was genotype dependent as autophagic markers like beclin1 and LC3 were induced in GNAQ-mutant cells, whereas apoptosis was the mechanism of cell death of BRAF-mutant cells, and cells without either mutation underwent cell-cycle arrest. The inhibition of MEK/ATK pathways induced activation of AMP-activated protein kinase (AMPK) in the GNAQ-mutant cells. The downregulation of AMPK by siRNA or its inhibition with compound C did not rescue the cells from autophagy, rather they died by apoptosis, defining AMPK as a key regulator of mutant GNAQ signaling and a switch between autophagy and apoptosis. Furthermore, this combination treatment was effective in inhibiting tumor growth in xenograft mouse models. These findings suggest that inhibition of MEK and AKT may represent a promising approach for targeted therapy of patients with uveal melanoma. (c) 2013 AACR.