Basal and treatment-induced activation of AKT mediates resistance to cell death by AZD6244 (ARRY-142886) in Braf-mutant human cutaneous melanoma cells.
Basal and treatment-induced activation of AKT mediates resistance to cell death by AZD6244 (ARRY-142886) in Braf-mutant human cutaneous melanoma cells.
复制标题
DOI：
10.1158/0008-5472.can-10-0902
复制
发表时间：
2010-11-01
期刊：
影响因子：
11.2
通讯作者：
Davies MA
中科院分区：
文献类型：
--
作者：
Gopal YN;Deng W;Woodman SE;Komurov K;Ram P;Smith PD;Davies MA
大多数黑色素瘤表现出RAS-RAF-MEK-MAPK通路的组成性激活。AZD 6244是一种选择性MEK 1/2抑制剂，可显著降低肿瘤P-MAPK水平，但在黑色素瘤患者中几乎没有临床反应。对AZD 6244耐药决定因素的进一步了解可能会改善患者选择和有效的组合方法。在总共14个Braf突变体和3个野生型人皮肤黑色素瘤细胞系中测试了AZD 6244对细胞生长和存活的影响。通过反相蛋白阵列（RPPA）分析定量评估Braf突变细胞系中的磷蛋白水平，显示P-MEK或P-MAPK水平与AZD 6244敏感性之间无显著相关性，但PI 3 K-AKT途径中的活化特异性标志物与耐药性相关。我们还鉴定了没有PI 3 K-AKT途径的基础活化的抗性细胞系。RPPA表征信号通路的时间依赖性变化显示，AZD 6244在敏感和耐药Braf突变细胞系中产生持久和有效的P-MAPK抑制，但几个耐药细胞系显示AZD 6244诱导AKT激活。相反，敏感细胞系显示AZD 6244处理诱导的PTEN蛋白和mRNA表达上调。抑制AKT、TORC 1/2或IGF 1 R可阻断AZD 6244诱导的AKT激活，并导致AZD 6244协同细胞杀伤。这些发现确定了基础和治疗诱导的PI 3 K-AKT通路调节作为Braf突变皮肤黑色素瘤细胞中AZD 6244敏感性的关键调节因子，AZD 6244在敏感细胞中对PTEN表达的新调节，并为患者提出了新的组合方法。
The majority of melanomas demonstrate constitutive activation of the RAS-RAF-MEK-MAPK pathway. AZD6244 is a selective MEK1/2 inhibitor which markedly reduces tumor P-MAPK levels, but it produced few clinical responses in melanoma patients. An improved understanding of the determinants of resistance to AZD6244 may lead to improved patient selection and effective combinatorial approaches. The effects of AZD6244 on cell growth and survival were tested in a total of 14 Braf-mutant and 3 wild-type human cutaneous melanoma cell lines. Quantitative assessment of phospho-protein levels in the Braf-mutant cell lines by reverse phase protein array (RPPA) analysis showed no significant association between P-MEK or P-MAPK levels and AZD6244 sensitivity, but activation-specific markers in the PI3K-AKT pathway correlated with resistance. We also identified resistant cell lines without basal activation of the PI3K-AKT pathway. RPPA characterization of the time-dependent changes in signaling pathways revealed that AZD6244 produced durable and potent inhibition of P-MAPK in sensitive and resistant Braf-mutant cell lines, but several resistant lines demonstrated AZD6244-induced activation of AKT. In contrast, sensitive cell lines demonstrated AZD6244 treatment-induced upregulation of PTEN protein and mRNA expression. Inhibition of AKT, TORC1/2, or IGF1R blocked AZD6244-induced activation of AKT and resulted in synergistic cell killing with AZD6244. These findings identify basal and treatment-induced regulation of the PI3K-AKT pathway as a critical regulator of AZD6244 sensitivity in Braf-mutant cutaneous melanoma cells, the novel regulation of PTEN expression by AZD6244 in sensitive cells, and suggest new combinatorial approaches for patients.