Center for Medical Genetics, Ghent University Hospital, Ghent, Belgium.
Department of Pediatric Oncology and Haematology, University Children's Hospital Essen, Germany.
Clin Cancer Res. 2015 Jul 15;21(14):3327-39. doi: 10.1158/1078-0432.CCR-14-2024. Epub 2015 Mar 24.
Activating ALK mutations are present in almost 10% of primary neuroblastomas and mark patients for treatment with small-molecule ALK inhibitors in clinical trials. However, recent studies have shown that multiple mechanisms drive resistance to these molecular therapies. We anticipated that detailed mapping of the oncogenic ALK-driven signaling in neuroblastoma can aid to identify potential fragile nodes as additional targets for combination therapies.
To achieve this goal, transcriptome profiling was performed in neuroblastoma cell lines with the ALK(F1174L) or ALK(R1275Q) hotspot mutations, ALK amplification, or wild-type ALK following pharmacologic inhibition of ALK using four different compounds. Next, we performed cross-species genomic analyses to identify commonly transcriptionally perturbed genes in MYCN/ALK(F1174L) double transgenic versus MYCN transgenic mouse tumors as compared with the mutant ALK-driven transcriptome in human neuroblastomas.
A 77-gene ALK signature was established and successfully validated in primary neuroblastoma samples, in a neuroblastoma cell line with ALK(F1174L) and ALK(R1275Q) regulable overexpression constructs and in other ALKomas. In addition to the previously established PI3K/AKT/mTOR, MAPK/ERK, and MYC/MYCN signaling branches, we identified that mutant ALK drives a strong upregulation of MAPK negative feedback regulators and upregulates RET and RET-driven sympathetic neuronal markers of the cholinergic lineage.
We provide important novel insights into the transcriptional consequences and the complexity of mutant ALK signaling in this aggressive pediatric tumor. The negative feedback loop of MAPK pathway inhibitors may affect novel ALK inhibition therapies, whereas mutant ALK induced RET signaling can offer novel opportunities for testing ALK-RET oriented molecular combination therapies.
ALK 激活突变存在于近 10%的原发性神经母细胞瘤中，并标志着这些患者适合在临床试验中接受小分子 ALK 抑制剂治疗。然而，最近的研究表明，多种机制会导致对这些分子疗法的耐药性。我们预计，对神经母细胞瘤中致癌性 ALK 驱动信号的详细研究将有助于确定潜在的脆弱节点，作为联合治疗的额外靶点。
为了实现这一目标，我们对具有 ALK(F1174L)或 ALK(R1275Q)热点突变、ALK 扩增或野生型 ALK 的神经母细胞瘤细胞系，在使用四种不同化合物抑制 ALK 后，进行了转录组谱分析。接下来，我们进行了跨物种基因组分析，以确定与人类神经母细胞瘤中突变型 ALK 驱动的转录组相比，在 MYCN/ALK(F1174L)双转基因小鼠肿瘤与 MYCN 转基因小鼠肿瘤中共同转录失调的基因。
建立了一个由 77 个基因组成的 ALK 特征，并在原发性神经母细胞瘤样本、具有 ALK(F1174L)和 ALK(R1275Q)可调节过表达构建体的神经母细胞瘤细胞系以及其他 ALK 瘤中成功验证。除了先前建立的 PI3K/AKT/mTOR、MAPK/ERK 和 MYC/MYCN 信号通路分支外，我们还发现突变型 ALK 会强烈上调 MAPK 负反馈调节剂，并上调 RET 和 RET 驱动的胆碱能谱系交感神经元标记物。
我们提供了关于这种侵袭性儿科肿瘤中突变型 ALK 信号的转录后果和复杂性的重要新见解。MAPK 通路抑制剂的负反馈回路可能会影响新型 ALK 抑制治疗，而突变型 ALK 诱导的 RET 信号可能为测试 ALK-RET 定向的分子联合治疗提供新的机会。
