Concurrent MEK and autophagy inhibition is required to restore cell death associated danger-signalling in Vemurafenib-resistant melanoma cells
Concurrent MEK and autophagy inhibition is required to restore cell death associated danger-signalling in Vemurafenib-resistant melanoma cells
复制标题
DOI：
10.1016/j.bcp.2014.12.003
复制
发表时间：
2015-02-01
影响因子：
5.8
通讯作者：
Agostinis, P.
中科院分区：
文献类型：
--
作者：
Martin, S.;Dudek-Peric, A. M.;Agostinis, P.
Vemurafenib（PLX 4032）是BRAF（V600 E）的抑制剂，已证明具有显著的临床抗黑色素瘤作用。然而，由于多种分子机制，包括通过MEK的MAPK再活化，大多数治疗的患者产生耐药性。诱导癌细胞死亡模式与β-信号传导相关，导致关键损伤相关分子模式（DAMP）（例如钙网蛋白（CRT）和热休克蛋白-90（HSP 90））从垂死细胞的表面动员，这对于治疗成功至关重要。细胞死亡和凋亡信号都受到自噬的调节，自噬是黑色素瘤进展过程中刺激的一种关键适应机制。然而，MAPK抑制诱导的黑色素瘤细胞死亡是否与MAPK信号传导相关，以及这些机制对自噬的依赖性，尚未被仔细研究。使用一组同基因PLX 4032敏感和耐药黑色素瘤细胞系，我们表明，PLX 4032诱导的药物敏感细胞中的半胱天冬酶依赖性细胞死亡和DAMP暴露，但在耐药细胞中未能做到这一点，显示出MEK活性增强MEK抑制剂U 0126处理使PLX 4032抗性细胞致敏死亡，并重新建立了它们的ERK信号传导能力。只有暴露死亡诱导的信号的黑色素瘤细胞被吞噬并诱导DC成熟。尽管PLX 4032抗性黑色素瘤细胞显示出更高的基础和药物诱导的自噬，但通过ATG 5敲低或通过破坏自噬不足以重建其PLX 4032敏感性。有趣的是，在通过U 0126阻断MEK超活化后，自噬消除在PLX 4032抗性细胞中促进细胞死亡和外-CRT/外-HSP 90方面特别有效。因此，MEK抑制剂与自噬阻断剂的组合可能代表了一种新的治疗方案，以增加Vemurafenib抗性转移性黑素瘤中的细胞死亡和外-CRT-信号传导。(C)2015 Elsevier Inc. All rights reserved.
Vemurafenib (PLX4032), an inhibitor of BRAF(V600E), has demonstrated significant clinical anti-melanoma effects. However, the majority of treated patients develop resistance, due to a variety of molecular mechanisms including MAPK reactivation through MEK. The induction of a cancer cell death modality associated with danger-signalling resulting in surface mobilization of crucial damage-associated-molecular-patterns (DAMPs), e.g. calreticulin (CRT) and heat shock protein-90 (HSP90), from dying cells, is emerging to be crucial for therapeutic success. Both cell death and danger-signalling are modulated by autophagy, a key adaptation mechanism stimulated during melanoma progression. However, whether melanoma cell death induced by MAPK inhibition is associated with danger-signalling, and the reliance of these mechanisms on autophagy, has not yet been scrutinized.Using a panel of isogenic PLX4032-sensitive and resistant melanoma cell lines we show that PLX4032-induced caspase-dependent cell death and DAMPs exposure in the drug-sensitive cells, but failed to do so in the drug-resistant cells, displaying heightened MEK activation. MEK inhibitor, U0126, treatment sensitized PLX4032-resistant cells to death and re-established their danger-signalling capacity. Only melanoma cells exposing death-induced danger-signals were phagocytosed and induced DC maturation. Although the PLX4032-resistant melanoma cells displayed higher basal and drug-induced autophagy, compromising autophagy, pharmacologically or by ATG5 knockdown, was insufficient to re-establish their PLX4032 sensitivity. Interestingly, autophagy abrogation was particularly efficacious in boosting cell death and ecto-CRT/ecto-HSP90 in PLX4032-resistant cells upon blockage of MEK hyper-activation by U0126.Thus combination of MEK inhibitors with autophagy blockers may represent a novel treatment regime to increase both cell death and danger-signalling in Vemurafenib-resistant metastatic melanoma. (C) 2015 Elsevier Inc. All rights reserved.