*Discovery Services, †Genomics Center, WuXi AppTec Co., Ltd., Shanghai, China;‡Pfizer Oncology Research Unit, San Diego, California; and §Department of Pathology, Shanghai Cancer Center, Fudan University, Shanghai, China.
J Thorac Oncol. 2014 Mar;9(3):285-94. doi: 10.1097/JTO.0000000000000087.
The aim of this study was to identify anaplastic lymphoma kinase (ALK) rearrangements in lung cancer patient-derived xenograft (PDX) models and to explore their responses to crizotinib.
Screening of 99 lung cancer PDX models by the NanoString ALK fusion assay identified two ALK-rearranged non-small-cell lung cancer (NSCLC) tumors, including one harboring a previously known echinoderm microtubule-associated protein-like 4 (EML4)-ALK fusion and another containing an unknown ALK fusion variant. Expression array, RNA-Seq, reverse transcription polymerase chain reaction, and direct sequencing were then conducted to confirm the rearrangements and to identify the novel fusion partner in the xenograft and/or the primary patient tumor. Finally, pharmacological studies were performed in PDX models to evaluate their responses to ALK inhibitor crizotinib.
Two ALK-rearranged NSCLC PDX models were identified: one carried a well-known EML4-ALK variant 3a/b and the other harbored a novel huntingtin interacting protein 1 (HIP1)-ALK fusion gene. Exon 28 of the HIP1 gene located on chromosome 7 was fused to exon 20 of the ALK gene located on chromosome 2. Both cases were clinically diagnosed as squamous cell carcinoma. Compared with the other lung cancer PDX models, both ALK-rearranged models displayed elevated ALK mRNA expression. Furthermore, in vivo efficacy studies demonstrated that, similar to the EML4-ALK-positive model, the HIP1-ALK-containing PDX model was sensitive to treatment with crizotinib.
Discovery of HIP1 as a fusion partner of ALK in NSCLC is a novel finding. In addition, the HIP1-ALK-rearranged tumor is sensitive to treatment with crizotinib in vivo, implicating HIP1-ALKas an oncogenic driver of lung tumorigenesis. Collectively, our results indicate that HIP1-ALK-positive NSCLC may benefit from clinical applications of crizotinib.
本研究旨在鉴定肺癌患者来源异种移植（PDX）模型中的间变性淋巴瘤激酶（ALK）重排，并探索其对克唑替尼的反应。
通过 NanoString ALK 融合检测法筛选 99 个肺癌 PDX 模型，鉴定出两个 ALK 重排的非小细胞肺癌（NSCLC）肿瘤，其中一个含有先前已知的棘皮动物微管相关蛋白样 4（EML4）-ALK 融合，另一个含有未知的 ALK 融合变异体。然后进行表达谱、RNA-Seq、反转录聚合酶链反应和直接测序，以确认重排，并鉴定异种移植和/或原始患者肿瘤中的新融合伙伴。最后，在 PDX 模型中进行药物学研究，以评估它们对 ALK 抑制剂克唑替尼的反应。
鉴定出两个 ALK 重排的 NSCLC PDX 模型：一个携带已知的 EML4-ALK 变体 3a/b，另一个携带新的亨廷顿相互作用蛋白 1（HIP1）-ALK 融合基因。HIP1 基因的外显子 28 位于染色体 7 上，与位于染色体 2 上的 ALK 基因的外显子 20 融合。两种情况均被临床诊断为鳞状细胞癌。与其他肺癌 PDX 模型相比，两种 ALK 重排模型的 ALK mRNA 表达均升高。此外，体内疗效研究表明，与 EML4-ALK 阳性模型相似，HIP1-ALK 阳性 PDX 模型对克唑替尼的治疗敏感。
在 NSCLC 中发现 HIP1 作为 ALK 的融合伙伴是一个新发现。此外，HIP1-ALK 重排肿瘤在体内对克唑替尼治疗敏感，提示 HIP1-ALK 是肺肿瘤发生的致癌驱动因素。综上所述，我们的结果表明，HIP1-ALK 阳性 NSCLC 可能受益于克唑替尼的临床应用。
